From nobody Tue Jun 23 05:03:32 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 366DDC433EF for ; Thu, 10 Mar 2022 14:24:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240471AbiCJOZT (ORCPT ); Thu, 10 Mar 2022 09:25:19 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55754 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241727AbiCJOVM (ORCPT ); Thu, 10 Mar 2022 09:21:12 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 59A775FBC; Thu, 10 Mar 2022 06:20:10 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id E6CFA61D02; Thu, 10 Mar 2022 14:20:09 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id D6873C340E8; Thu, 10 Mar 2022 14:20:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1646922009; bh=mSc6PRGfJhS8fiw4SnlPOu1Av93ntIA6/0VNlY/8NbE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=XjmULAcfMaCYfMSfgHprCBrOm7MHyvKxDDHGNvLXAFUNZlJfQpp/VfwsPY+5NSXSU By5g9GW91sZtTkCB72gHEWvJgCswMsRW3WQysrnx9O+wb4tpN1XtKGmU99JgtL4q3m yslPCOCJIj3H0SUaIUxdojLtfUv3gjZNtUXV44ls= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Borislav Petkov , Anthony Steinhauser , Frank van der Linden Subject: [PATCH 4.14 01/31] x86/speculation: Merge one test in spectre_v2_user_select_mitigation() Date: Thu, 10 Mar 2022 15:18:14 +0100 Message-Id: <20220310140807.570546096@linuxfoundation.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220310140807.524313448@linuxfoundation.org> References: <20220310140807.524313448@linuxfoundation.org> User-Agent: quilt/0.66 X-stable: review X-Patchwork-Hint: ignore MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: Borislav Petkov commit a5ce9f2bb665d1d2b31f139a02dbaa2dfbb62fa6 upstream. Merge the test whether the CPU supports STIBP into the test which determines whether STIBP is required. Thus try to simplify what is already an insane logic. Remove a superfluous newline in a comment, while at it. Signed-off-by: Borislav Petkov Cc: Anthony Steinhauser Link: https://lkml.kernel.org/r/20200615065806.GB14668@zn.tnic [fllinden@amazon.com: fixed contextual conflict (comment) for 4.14] Signed-off-by: Frank van der Linden Signed-off-by: Greg Kroah-Hartman Tested-by: Guenter Roeck Tested-by: Linux Kernel Functional Testing --- arch/x86/kernel/cpu/bugs.c | 13 ++++--------- 1 file changed, 4 insertions(+), 9 deletions(-) --- a/arch/x86/kernel/cpu/bugs.c +++ b/arch/x86/kernel/cpu/bugs.c @@ -756,10 +756,12 @@ spectre_v2_user_select_mitigation(enum s } =20 /* - * If enhanced IBRS is enabled or SMT impossible, STIBP is not + * If no STIBP, enhanced IBRS is enabled or SMT impossible, STIBP is not * required. */ - if (!smt_possible || spectre_v2_enabled =3D=3D SPECTRE_V2_IBRS_ENHANCED) + if (!boot_cpu_has(X86_FEATURE_STIBP) || + !smt_possible || + spectre_v2_enabled =3D=3D SPECTRE_V2_IBRS_ENHANCED) return; =20 /* @@ -771,12 +773,6 @@ spectre_v2_user_select_mitigation(enum s boot_cpu_has(X86_FEATURE_AMD_STIBP_ALWAYS_ON)) mode =3D SPECTRE_V2_USER_STRICT_PREFERRED; =20 - /* - * If STIBP is not available, clear the STIBP mode. - */ - if (!boot_cpu_has(X86_FEATURE_STIBP)) - mode =3D SPECTRE_V2_USER_NONE; - spectre_v2_user_stibp =3D mode; =20 set_mode: @@ -1255,7 +1251,6 @@ static int ib_prctl_set(struct task_stru if (spectre_v2_user_ibpb =3D=3D SPECTRE_V2_USER_NONE && spectre_v2_user_stibp =3D=3D SPECTRE_V2_USER_NONE) return 0; - /* * With strict mode for both IBPB and STIBP, the instruction * code paths avoid checking this task flag and instead, From nobody Tue Jun 23 05:03:32 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id A62E7C433EF for ; Thu, 10 Mar 2022 14:25:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243658AbiCJO0t (ORCPT ); Thu, 10 Mar 2022 09:26:49 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56852 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243430AbiCJOWB (ORCPT ); Thu, 10 Mar 2022 09:22:01 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 450DFB91D3; Thu, 10 Mar 2022 06:20:46 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id C898561CEE; Thu, 10 Mar 2022 14:20:45 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id D4B4AC340E8; Thu, 10 Mar 2022 14:20:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1646922045; bh=hqtcupg/S7vlWPIHEZ3+ea8d0QaSg8jJW+0Mknfouuk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=0zHTI+Ab6mTNQ5eY6g+XQ3k+Nk2EFgAlADBY+Liip4Y3+nKkMWd3JwWV/c5ebaWny 4Q13qUDRkZ/Ledrg/lSBKGL+Cmm1UTRg/UsHjIJWB9xTOQQrYE1GUfQGQBj0VcJcGO EUmCPP2gNmKIU6M0UptSSWvkrT2L9+J3GQ1lNHJw= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, "Peter Zijlstra (Intel)" , Borislav Petkov , Josh Poimboeuf , Alexei Starovoitov , Frank van der Linden Subject: [PATCH 4.14 02/31] x86,bugs: Unconditionally allow spectre_v2=retpoline,amd Date: Thu, 10 Mar 2022 15:18:15 +0100 Message-Id: <20220310140807.600031247@linuxfoundation.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220310140807.524313448@linuxfoundation.org> References: <20220310140807.524313448@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: Peter Zijlstra commit f8a66d608a3e471e1202778c2a36cbdc96bae73b upstream. Currently Linux prevents usage of retpoline,amd on !AMD hardware, this is unfriendly and gets in the way of testing. Remove this restriction. Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Borislav Petkov Acked-by: Josh Poimboeuf Tested-by: Alexei Starovoitov Link: https://lore.kernel.org/r/20211026120310.487348118@infradead.org [fllinden@amazon.com: backported to 4.14 (no Hygon in 4.14)] Signed-off-by: Frank van der Linden Signed-off-by: Greg Kroah-Hartman Tested-by: Guenter Roeck Tested-by: Linux Kernel Functional Testing --- arch/x86/kernel/cpu/bugs.c | 6 ------ 1 file changed, 6 deletions(-) --- a/arch/x86/kernel/cpu/bugs.c +++ b/arch/x86/kernel/cpu/bugs.c @@ -839,12 +839,6 @@ static enum spectre_v2_mitigation_cmd __ return SPECTRE_V2_CMD_AUTO; } =20 - if (cmd =3D=3D SPECTRE_V2_CMD_RETPOLINE_AMD && - boot_cpu_data.x86_vendor !=3D X86_VENDOR_AMD) { - pr_err("retpoline,amd selected but CPU is not AMD. Switching to AUTO sel= ect\n"); - return SPECTRE_V2_CMD_AUTO; - } - spec_v2_print_cond(mitigation_options[i].option, mitigation_options[i].secure); return cmd; From nobody Tue Jun 23 05:03:32 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 74B98C433F5 for ; Thu, 10 Mar 2022 14:26:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243649AbiCJO1h (ORCPT ); Thu, 10 Mar 2022 09:27:37 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56852 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243342AbiCJOZA (ORCPT ); Thu, 10 Mar 2022 09:25:00 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0AD6515C9E5; Thu, 10 Mar 2022 06:21:34 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id B86AFB8267B; Thu, 10 Mar 2022 14:21:20 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id F185EC36AE3; Thu, 10 Mar 2022 14:21:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1646922079; bh=yHBwrv2aWD/9H1DZRrYgDaAP2sk5Lz5EFwkKNbq0IRo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=mvvsHoyH1pbyQYhXL0/jIa/SJfhbvONAPUII3SRxnMT+Bdij4u/QO7Hl5WlIJ+fDW RZHfaIkxVwOvHifJNOumcgJE8vI4HOABaxJO1qObA2bhNj8YyIKZzEfkJbOYlXUbtl IYGAjD1aJGh3wpnaDkAcICh19G+2vtpHkVjr7NTE= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Josh Poimboeuf , "Peter Zijlstra (Intel)" , Borislav Petkov , Thomas Gleixner , Frank van der Linden Subject: [PATCH 4.14 03/31] x86/speculation: Rename RETPOLINE_AMD to RETPOLINE_LFENCE Date: Thu, 10 Mar 2022 15:18:16 +0100 Message-Id: <20220310140807.628938039@linuxfoundation.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220310140807.524313448@linuxfoundation.org> References: <20220310140807.524313448@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: "Peter Zijlstra (Intel)" commit d45476d9832409371537013ebdd8dc1a7781f97a upstream. The RETPOLINE_AMD name is unfortunate since it isn't necessarily AMD only, in fact Hygon also uses it. Furthermore it will likely be sufficient for some Intel processors. Therefore rename the thing to RETPOLINE_LFENCE to better describe what it is. Add the spectre_v2=3Dretpoline,lfence option as an alias to spectre_v2=3Dretpoline,amd to preserve existing setups. However, the output of /sys/devices/system/cpu/vulnerabilities/spectre_v2 will be changed. [ bp: Fix typos, massage. ] Co-developed-by: Josh Poimboeuf Signed-off-by: Josh Poimboeuf Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Borislav Petkov Reviewed-by: Thomas Gleixner [fllinden@amazon.com: backported to 4.14] Signed-off-by: Frank van der Linden Signed-off-by: Greg Kroah-Hartman Tested-by: Guenter Roeck Tested-by: Linux Kernel Functional Testing --- arch/x86/include/asm/cpufeatures.h | 2 +- arch/x86/include/asm/nospec-branch.h | 12 ++++++------ arch/x86/kernel/cpu/bugs.c | 29 ++++++++++++++++++--------= --- tools/arch/x86/include/asm/cpufeatures.h | 2 +- 4 files changed, 26 insertions(+), 19 deletions(-) --- a/arch/x86/include/asm/cpufeatures.h +++ b/arch/x86/include/asm/cpufeatures.h @@ -203,7 +203,7 @@ #define X86_FEATURE_SME ( 7*32+10) /* AMD Secure Memory Encryption */ #define X86_FEATURE_PTI ( 7*32+11) /* Kernel Page Table Isolation enable= d */ #define X86_FEATURE_RETPOLINE ( 7*32+12) /* "" Generic Retpoline mitigati= on for Spectre variant 2 */ -#define X86_FEATURE_RETPOLINE_AMD ( 7*32+13) /* "" AMD Retpoline mitigatio= n for Spectre variant 2 */ +#define X86_FEATURE_RETPOLINE_LFENCE ( 7*32+13) /* "" Use LFENCE for Spect= re variant 2 */ #define X86_FEATURE_INTEL_PPIN ( 7*32+14) /* Intel Processor Inventory Nu= mber */ #define X86_FEATURE_CDP_L2 ( 7*32+15) /* Code and Data Prioritization L2 = */ #define X86_FEATURE_MSR_SPEC_CTRL ( 7*32+16) /* "" MSR SPEC_CTRL is implem= ented */ --- a/arch/x86/include/asm/nospec-branch.h +++ b/arch/x86/include/asm/nospec-branch.h @@ -119,7 +119,7 @@ ANNOTATE_NOSPEC_ALTERNATIVE ALTERNATIVE_2 __stringify(ANNOTATE_RETPOLINE_SAFE; jmp *\reg), \ __stringify(RETPOLINE_JMP \reg), X86_FEATURE_RETPOLINE, \ - __stringify(lfence; ANNOTATE_RETPOLINE_SAFE; jmp *\reg), X86_FEATURE_RET= POLINE_AMD + __stringify(lfence; ANNOTATE_RETPOLINE_SAFE; jmp *\reg), X86_FEATURE_RET= POLINE_LFENCE #else jmp *\reg #endif @@ -130,7 +130,7 @@ ANNOTATE_NOSPEC_ALTERNATIVE ALTERNATIVE_2 __stringify(ANNOTATE_RETPOLINE_SAFE; call *\reg), \ __stringify(RETPOLINE_CALL \reg), X86_FEATURE_RETPOLINE,\ - __stringify(lfence; ANNOTATE_RETPOLINE_SAFE; call *\reg), X86_FEATURE_RE= TPOLINE_AMD + __stringify(lfence; ANNOTATE_RETPOLINE_SAFE; call *\reg), X86_FEATURE_RE= TPOLINE_LFENCE #else call *\reg #endif @@ -181,7 +181,7 @@ "lfence;\n" \ ANNOTATE_RETPOLINE_SAFE \ "call *%[thunk_target]\n", \ - X86_FEATURE_RETPOLINE_AMD) + X86_FEATURE_RETPOLINE_LFENCE) # define THUNK_TARGET(addr) [thunk_target] "r" (addr) =20 #else /* CONFIG_X86_32 */ @@ -211,7 +211,7 @@ "lfence;\n" \ ANNOTATE_RETPOLINE_SAFE \ "call *%[thunk_target]\n", \ - X86_FEATURE_RETPOLINE_AMD) + X86_FEATURE_RETPOLINE_LFENCE) =20 # define THUNK_TARGET(addr) [thunk_target] "rm" (addr) #endif @@ -223,8 +223,8 @@ /* The Spectre V2 mitigation variants */ enum spectre_v2_mitigation { SPECTRE_V2_NONE, - SPECTRE_V2_RETPOLINE_GENERIC, - SPECTRE_V2_RETPOLINE_AMD, + SPECTRE_V2_RETPOLINE, + SPECTRE_V2_LFENCE, SPECTRE_V2_IBRS_ENHANCED, }; =20 --- a/arch/x86/kernel/cpu/bugs.c +++ b/arch/x86/kernel/cpu/bugs.c @@ -621,7 +621,7 @@ enum spectre_v2_mitigation_cmd { SPECTRE_V2_CMD_FORCE, SPECTRE_V2_CMD_RETPOLINE, SPECTRE_V2_CMD_RETPOLINE_GENERIC, - SPECTRE_V2_CMD_RETPOLINE_AMD, + SPECTRE_V2_CMD_RETPOLINE_LFENCE, }; =20 enum spectre_v2_user_cmd { @@ -781,8 +781,8 @@ set_mode: =20 static const char * const spectre_v2_strings[] =3D { [SPECTRE_V2_NONE] =3D "Vulnerable", - [SPECTRE_V2_RETPOLINE_GENERIC] =3D "Mitigation: Full generic retpoline", - [SPECTRE_V2_RETPOLINE_AMD] =3D "Mitigation: Full AMD retpoline", + [SPECTRE_V2_RETPOLINE] =3D "Mitigation: Retpolines", + [SPECTRE_V2_LFENCE] =3D "Mitigation: LFENCE", [SPECTRE_V2_IBRS_ENHANCED] =3D "Mitigation: Enhanced IBRS", }; =20 @@ -794,7 +794,8 @@ static const struct { { "off", SPECTRE_V2_CMD_NONE, false }, { "on", SPECTRE_V2_CMD_FORCE, true }, { "retpoline", SPECTRE_V2_CMD_RETPOLINE, false }, - { "retpoline,amd", SPECTRE_V2_CMD_RETPOLINE_AMD, false }, + { "retpoline,amd", SPECTRE_V2_CMD_RETPOLINE_LFENCE, false }, + { "retpoline,lfence", SPECTRE_V2_CMD_RETPOLINE_LFENCE, false }, { "retpoline,generic", SPECTRE_V2_CMD_RETPOLINE_GENERIC, false }, { "auto", SPECTRE_V2_CMD_AUTO, false }, }; @@ -832,13 +833,19 @@ static enum spectre_v2_mitigation_cmd __ } =20 if ((cmd =3D=3D SPECTRE_V2_CMD_RETPOLINE || - cmd =3D=3D SPECTRE_V2_CMD_RETPOLINE_AMD || + cmd =3D=3D SPECTRE_V2_CMD_RETPOLINE_LFENCE || cmd =3D=3D SPECTRE_V2_CMD_RETPOLINE_GENERIC) && !IS_ENABLED(CONFIG_RETPOLINE)) { pr_err("%s selected but not compiled in. Switching to AUTO select\n", mi= tigation_options[i].option); return SPECTRE_V2_CMD_AUTO; } =20 + if ((cmd =3D=3D SPECTRE_V2_CMD_RETPOLINE_LFENCE) && + !boot_cpu_has(X86_FEATURE_LFENCE_RDTSC)) { + pr_err("%s selected, but CPU doesn't have a serializing LFENCE. Switchin= g to AUTO select\n", mitigation_options[i].option); + return SPECTRE_V2_CMD_AUTO; + } + spec_v2_print_cond(mitigation_options[i].option, mitigation_options[i].secure); return cmd; @@ -873,9 +880,9 @@ static void __init spectre_v2_select_mit if (IS_ENABLED(CONFIG_RETPOLINE)) goto retpoline_auto; break; - case SPECTRE_V2_CMD_RETPOLINE_AMD: + case SPECTRE_V2_CMD_RETPOLINE_LFENCE: if (IS_ENABLED(CONFIG_RETPOLINE)) - goto retpoline_amd; + goto retpoline_lfence; break; case SPECTRE_V2_CMD_RETPOLINE_GENERIC: if (IS_ENABLED(CONFIG_RETPOLINE)) @@ -891,17 +898,17 @@ static void __init spectre_v2_select_mit =20 retpoline_auto: if (boot_cpu_data.x86_vendor =3D=3D X86_VENDOR_AMD) { - retpoline_amd: + retpoline_lfence: if (!boot_cpu_has(X86_FEATURE_LFENCE_RDTSC)) { pr_err("Spectre mitigation: LFENCE not serializing, switching to generi= c retpoline\n"); goto retpoline_generic; } - mode =3D SPECTRE_V2_RETPOLINE_AMD; - setup_force_cpu_cap(X86_FEATURE_RETPOLINE_AMD); + mode =3D SPECTRE_V2_LFENCE; + setup_force_cpu_cap(X86_FEATURE_RETPOLINE_LFENCE); setup_force_cpu_cap(X86_FEATURE_RETPOLINE); } else { retpoline_generic: - mode =3D SPECTRE_V2_RETPOLINE_GENERIC; + mode =3D SPECTRE_V2_RETPOLINE; setup_force_cpu_cap(X86_FEATURE_RETPOLINE); } =20 --- a/tools/arch/x86/include/asm/cpufeatures.h +++ b/tools/arch/x86/include/asm/cpufeatures.h @@ -203,7 +203,7 @@ #define X86_FEATURE_SME ( 7*32+10) /* AMD Secure Memory Encryption */ #define X86_FEATURE_PTI ( 7*32+11) /* Kernel Page Table Isolation enable= d */ #define X86_FEATURE_RETPOLINE ( 7*32+12) /* "" Generic Retpoline mitigati= on for Spectre variant 2 */ -#define X86_FEATURE_RETPOLINE_AMD ( 7*32+13) /* "" AMD Retpoline mitigatio= n for Spectre variant 2 */ +#define X86_FEATURE_RETPOLINE_LFENCE ( 7*32+13) /* "" Use LFENCEs for Spec= tre variant 2 */ #define X86_FEATURE_INTEL_PPIN ( 7*32+14) /* Intel Processor Inventory Nu= mber */ =20 #define X86_FEATURE_MSR_SPEC_CTRL ( 7*32+16) /* "" MSR SPEC_CTRL is implem= ented */ From nobody Tue Jun 23 05:03:32 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0D952C433F5 for ; Thu, 10 Mar 2022 14:30:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243740AbiCJO1q (ORCPT ); Thu, 10 Mar 2022 09:27:46 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59034 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243598AbiCJOZD (ORCPT ); Thu, 10 Mar 2022 09:25:03 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 99A38160FD8; Thu, 10 Mar 2022 06:21:42 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id BF2DE61CFF; Thu, 10 Mar 2022 14:21:28 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id CB30BC340F3; Thu, 10 Mar 2022 14:21:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1646922088; bh=QYvbKUkSTXQCvEqdV0YhKZqOQ4aZn3ZVypCIaknyD24=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=FKuaHOwxyk2LQ+I2r8alJow9ivvhu8LMbkyqfdPB/jtHMzzWcTx0kJFQ0yvShPdyP Kfda6y5lHB8Tz84fslacn9eWB4XmvjTkn8FYaBCPFUKXypArocUPJrnFFuqNwUiPDR +9NEANwLAxCQPhO+6xvnjz0rM/tSjFDVOxBIziFI= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Josh Poimboeuf , "Peter Zijlstra (Intel)" , Borislav Petkov , Patrick Colp , Thomas Gleixner , Frank van der Linden Subject: [PATCH 4.14 04/31] x86/speculation: Add eIBRS + Retpoline options Date: Thu, 10 Mar 2022 15:18:17 +0100 Message-Id: <20220310140807.658264053@linuxfoundation.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220310140807.524313448@linuxfoundation.org> References: <20220310140807.524313448@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: Peter Zijlstra commit 1e19da8522c81bf46b335f84137165741e0d82b7 upstream. Thanks to the chaps at VUsec it is now clear that eIBRS is not sufficient, therefore allow enabling of retpolines along with eIBRS. Add spectre_v2=3Deibrs, spectre_v2=3Deibrs,lfence and spectre_v2=3Deibrs,retpoline options to explicitly pick your preferred means of mitigation. Since there's new mitigations there's also user visible changes in /sys/devices/system/cpu/vulnerabilities/spectre_v2 to reflect these new mitigations. [ bp: Massage commit message, trim error messages, do more precise eIBRS mode checking. ] Co-developed-by: Josh Poimboeuf Signed-off-by: Josh Poimboeuf Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Borislav Petkov Reviewed-by: Patrick Colp Reviewed-by: Thomas Gleixner [fllinden@amazon.com: backported to 4.14 (no Hygon)] Signed-off-by: Frank van der Linden Signed-off-by: Greg Kroah-Hartman Tested-by: Guenter Roeck Tested-by: Linux Kernel Functional Testing --- arch/x86/include/asm/nospec-branch.h | 4 - arch/x86/kernel/cpu/bugs.c | 131 +++++++++++++++++++++++++-----= ----- 2 files changed, 98 insertions(+), 37 deletions(-) --- a/arch/x86/include/asm/nospec-branch.h +++ b/arch/x86/include/asm/nospec-branch.h @@ -225,7 +225,9 @@ enum spectre_v2_mitigation { SPECTRE_V2_NONE, SPECTRE_V2_RETPOLINE, SPECTRE_V2_LFENCE, - SPECTRE_V2_IBRS_ENHANCED, + SPECTRE_V2_EIBRS, + SPECTRE_V2_EIBRS_RETPOLINE, + SPECTRE_V2_EIBRS_LFENCE, }; =20 /* The indirect branch speculation control variants */ --- a/arch/x86/kernel/cpu/bugs.c +++ b/arch/x86/kernel/cpu/bugs.c @@ -622,6 +622,9 @@ enum spectre_v2_mitigation_cmd { SPECTRE_V2_CMD_RETPOLINE, SPECTRE_V2_CMD_RETPOLINE_GENERIC, SPECTRE_V2_CMD_RETPOLINE_LFENCE, + SPECTRE_V2_CMD_EIBRS, + SPECTRE_V2_CMD_EIBRS_RETPOLINE, + SPECTRE_V2_CMD_EIBRS_LFENCE, }; =20 enum spectre_v2_user_cmd { @@ -694,6 +697,13 @@ spectre_v2_parse_user_cmdline(enum spect return SPECTRE_V2_USER_CMD_AUTO; } =20 +static inline bool spectre_v2_in_eibrs_mode(enum spectre_v2_mitigation mod= e) +{ + return (mode =3D=3D SPECTRE_V2_EIBRS || + mode =3D=3D SPECTRE_V2_EIBRS_RETPOLINE || + mode =3D=3D SPECTRE_V2_EIBRS_LFENCE); +} + static void __init spectre_v2_user_select_mitigation(enum spectre_v2_mitigation_cmd v2_cmd) { @@ -761,7 +771,7 @@ spectre_v2_user_select_mitigation(enum s */ if (!boot_cpu_has(X86_FEATURE_STIBP) || !smt_possible || - spectre_v2_enabled =3D=3D SPECTRE_V2_IBRS_ENHANCED) + spectre_v2_in_eibrs_mode(spectre_v2_enabled)) return; =20 /* @@ -783,7 +793,9 @@ static const char * const spectre_v2_str [SPECTRE_V2_NONE] =3D "Vulnerable", [SPECTRE_V2_RETPOLINE] =3D "Mitigation: Retpolines", [SPECTRE_V2_LFENCE] =3D "Mitigation: LFENCE", - [SPECTRE_V2_IBRS_ENHANCED] =3D "Mitigation: Enhanced IBRS", + [SPECTRE_V2_EIBRS] =3D "Mitigation: Enhanced IBRS", + [SPECTRE_V2_EIBRS_LFENCE] =3D "Mitigation: Enhanced IBRS + LFENCE", + [SPECTRE_V2_EIBRS_RETPOLINE] =3D "Mitigation: Enhanced IBRS + Retpolines= ", }; =20 static const struct { @@ -797,6 +809,9 @@ static const struct { { "retpoline,amd", SPECTRE_V2_CMD_RETPOLINE_LFENCE, false }, { "retpoline,lfence", SPECTRE_V2_CMD_RETPOLINE_LFENCE, false }, { "retpoline,generic", SPECTRE_V2_CMD_RETPOLINE_GENERIC, false }, + { "eibrs", SPECTRE_V2_CMD_EIBRS, false }, + { "eibrs,lfence", SPECTRE_V2_CMD_EIBRS_LFENCE, false }, + { "eibrs,retpoline", SPECTRE_V2_CMD_EIBRS_RETPOLINE, false }, { "auto", SPECTRE_V2_CMD_AUTO, false }, }; =20 @@ -834,15 +849,29 @@ static enum spectre_v2_mitigation_cmd __ =20 if ((cmd =3D=3D SPECTRE_V2_CMD_RETPOLINE || cmd =3D=3D SPECTRE_V2_CMD_RETPOLINE_LFENCE || - cmd =3D=3D SPECTRE_V2_CMD_RETPOLINE_GENERIC) && + cmd =3D=3D SPECTRE_V2_CMD_RETPOLINE_GENERIC || + cmd =3D=3D SPECTRE_V2_CMD_EIBRS_LFENCE || + cmd =3D=3D SPECTRE_V2_CMD_EIBRS_RETPOLINE) && !IS_ENABLED(CONFIG_RETPOLINE)) { - pr_err("%s selected but not compiled in. Switching to AUTO select\n", mi= tigation_options[i].option); + pr_err("%s selected but not compiled in. Switching to AUTO select\n", + mitigation_options[i].option); + return SPECTRE_V2_CMD_AUTO; + } + + if ((cmd =3D=3D SPECTRE_V2_CMD_EIBRS || + cmd =3D=3D SPECTRE_V2_CMD_EIBRS_LFENCE || + cmd =3D=3D SPECTRE_V2_CMD_EIBRS_RETPOLINE) && + !boot_cpu_has(X86_FEATURE_IBRS_ENHANCED)) { + pr_err("%s selected but CPU doesn't have eIBRS. Switching to AUTO select= \n", + mitigation_options[i].option); return SPECTRE_V2_CMD_AUTO; } =20 - if ((cmd =3D=3D SPECTRE_V2_CMD_RETPOLINE_LFENCE) && + if ((cmd =3D=3D SPECTRE_V2_CMD_RETPOLINE_LFENCE || + cmd =3D=3D SPECTRE_V2_CMD_EIBRS_LFENCE) && !boot_cpu_has(X86_FEATURE_LFENCE_RDTSC)) { - pr_err("%s selected, but CPU doesn't have a serializing LFENCE. Switchin= g to AUTO select\n", mitigation_options[i].option); + pr_err("%s selected, but CPU doesn't have a serializing LFENCE. Switchin= g to AUTO select\n", + mitigation_options[i].option); return SPECTRE_V2_CMD_AUTO; } =20 @@ -851,6 +880,24 @@ static enum spectre_v2_mitigation_cmd __ return cmd; } =20 +static enum spectre_v2_mitigation __init spectre_v2_select_retpoline(void) +{ + if (!IS_ENABLED(CONFIG_RETPOLINE)) { + pr_err("Kernel not compiled with retpoline; no mitigation available!"); + return SPECTRE_V2_NONE; + } + + if (boot_cpu_data.x86_vendor =3D=3D X86_VENDOR_AMD) { + if (!boot_cpu_has(X86_FEATURE_LFENCE_RDTSC)) { + pr_err("LFENCE not serializing, switching to generic retpoline\n"); + return SPECTRE_V2_RETPOLINE; + } + return SPECTRE_V2_LFENCE; + } + + return SPECTRE_V2_RETPOLINE; +} + static void __init spectre_v2_select_mitigation(void) { enum spectre_v2_mitigation_cmd cmd =3D spectre_v2_parse_cmdline(); @@ -871,48 +918,60 @@ static void __init spectre_v2_select_mit case SPECTRE_V2_CMD_FORCE: case SPECTRE_V2_CMD_AUTO: if (boot_cpu_has(X86_FEATURE_IBRS_ENHANCED)) { - mode =3D SPECTRE_V2_IBRS_ENHANCED; - /* Force it so VMEXIT will restore correctly */ - x86_spec_ctrl_base |=3D SPEC_CTRL_IBRS; - wrmsrl(MSR_IA32_SPEC_CTRL, x86_spec_ctrl_base); - goto specv2_set_mode; + mode =3D SPECTRE_V2_EIBRS; + break; } - if (IS_ENABLED(CONFIG_RETPOLINE)) - goto retpoline_auto; + + mode =3D spectre_v2_select_retpoline(); break; + case SPECTRE_V2_CMD_RETPOLINE_LFENCE: - if (IS_ENABLED(CONFIG_RETPOLINE)) - goto retpoline_lfence; + mode =3D SPECTRE_V2_LFENCE; break; + case SPECTRE_V2_CMD_RETPOLINE_GENERIC: - if (IS_ENABLED(CONFIG_RETPOLINE)) - goto retpoline_generic; + mode =3D SPECTRE_V2_RETPOLINE; break; + case SPECTRE_V2_CMD_RETPOLINE: - if (IS_ENABLED(CONFIG_RETPOLINE)) - goto retpoline_auto; + mode =3D spectre_v2_select_retpoline(); + break; + + case SPECTRE_V2_CMD_EIBRS: + mode =3D SPECTRE_V2_EIBRS; + break; + + case SPECTRE_V2_CMD_EIBRS_LFENCE: + mode =3D SPECTRE_V2_EIBRS_LFENCE; + break; + + case SPECTRE_V2_CMD_EIBRS_RETPOLINE: + mode =3D SPECTRE_V2_EIBRS_RETPOLINE; break; } - pr_err("Spectre mitigation: kernel not compiled with retpoline; no mitiga= tion available!"); - return; =20 -retpoline_auto: - if (boot_cpu_data.x86_vendor =3D=3D X86_VENDOR_AMD) { - retpoline_lfence: - if (!boot_cpu_has(X86_FEATURE_LFENCE_RDTSC)) { - pr_err("Spectre mitigation: LFENCE not serializing, switching to generi= c retpoline\n"); - goto retpoline_generic; - } - mode =3D SPECTRE_V2_LFENCE; + if (spectre_v2_in_eibrs_mode(mode)) { + /* Force it so VMEXIT will restore correctly */ + x86_spec_ctrl_base |=3D SPEC_CTRL_IBRS; + wrmsrl(MSR_IA32_SPEC_CTRL, x86_spec_ctrl_base); + } + + switch (mode) { + case SPECTRE_V2_NONE: + case SPECTRE_V2_EIBRS: + break; + + case SPECTRE_V2_LFENCE: + case SPECTRE_V2_EIBRS_LFENCE: setup_force_cpu_cap(X86_FEATURE_RETPOLINE_LFENCE); + /* fallthrough */ + + case SPECTRE_V2_RETPOLINE: + case SPECTRE_V2_EIBRS_RETPOLINE: setup_force_cpu_cap(X86_FEATURE_RETPOLINE); - } else { - retpoline_generic: - mode =3D SPECTRE_V2_RETPOLINE; - setup_force_cpu_cap(X86_FEATURE_RETPOLINE); + break; } =20 -specv2_set_mode: spectre_v2_enabled =3D mode; pr_info("%s\n", spectre_v2_strings[mode]); =20 @@ -938,7 +997,7 @@ specv2_set_mode: * the CPU supports Enhanced IBRS, kernel might un-intentionally not * enable IBRS around firmware calls. */ - if (boot_cpu_has(X86_FEATURE_IBRS) && mode !=3D SPECTRE_V2_IBRS_ENHANCED)= { + if (boot_cpu_has(X86_FEATURE_IBRS) && !spectre_v2_in_eibrs_mode(mode)) { setup_force_cpu_cap(X86_FEATURE_USE_IBRS_FW); pr_info("Enabling Restricted Speculation for firmware calls\n"); } @@ -1596,7 +1655,7 @@ static ssize_t tsx_async_abort_show_stat =20 static char *stibp_state(void) { - if (spectre_v2_enabled =3D=3D SPECTRE_V2_IBRS_ENHANCED) + if (spectre_v2_in_eibrs_mode(spectre_v2_enabled)) return ""; =20 switch (spectre_v2_user_stibp) { From nobody Tue Jun 23 05:03:32 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0DD7AC433F5 for ; Thu, 10 Mar 2022 14:30:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243847AbiCJO1x (ORCPT ); Thu, 10 Mar 2022 09:27:53 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58596 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243589AbiCJOZN (ORCPT ); Thu, 10 Mar 2022 09:25:13 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 130BB1617F2; Thu, 10 Mar 2022 06:21:49 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 4A1BAB8267D; Thu, 10 Mar 2022 14:21:32 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 95B3CC340E8; Thu, 10 Mar 2022 14:21:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1646922091; bh=EbrEZQ50EN7O9KAn4zxvfpRaHNZyBkM467lX/zI6ot8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ss8lsf10FJuo4DvZEPhXp1ZTGsSxcDoJFA7Hodb+9Mj/qqvIMRMX6+hHxEmtZmLCg 3/lIvLZ5MNfe8nrJaQXVHywDIUEAJ5hFh0hBn4waT1es+8fOIS5qEupVBOZmCc7KYB nOaYot3QrqE+SW8LziS/fGdzW9sDp9Sd6cEevoQ4= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, "Peter Zijlstra (Intel)" , Borislav Petkov , Thomas Gleixner , Frank van der Linden Subject: [PATCH 4.14 05/31] Documentation/hw-vuln: Update spectre doc Date: Thu, 10 Mar 2022 15:18:18 +0100 Message-Id: <20220310140807.688038300@linuxfoundation.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220310140807.524313448@linuxfoundation.org> References: <20220310140807.524313448@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: Peter Zijlstra commit 5ad3eb1132453b9795ce5fd4572b1c18b292cca9 upstream. Update the doc with the new fun. [ bp: Massage commit message. ] Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Borislav Petkov Reviewed-by: Thomas Gleixner [fllinden@amazon.com: backported to 4.14] Signed-off-by: Frank van der Linden Signed-off-by: Greg Kroah-Hartman Tested-by: Guenter Roeck Tested-by: Linux Kernel Functional Testing --- Documentation/admin-guide/hw-vuln/spectre.rst | 42 ++++++++++++++++---= ----- Documentation/admin-guide/kernel-parameters.txt | 8 +++- 2 files changed, 35 insertions(+), 15 deletions(-) --- a/Documentation/admin-guide/hw-vuln/spectre.rst +++ b/Documentation/admin-guide/hw-vuln/spectre.rst @@ -131,6 +131,19 @@ steer its indirect branch speculations t speculative execution's side effects left in level 1 cache to infer the victim's data. =20 +Yet another variant 2 attack vector is for the attacker to poison the +Branch History Buffer (BHB) to speculatively steer an indirect branch +to a specific Branch Target Buffer (BTB) entry, even if the entry isn't +associated with the source address of the indirect branch. Specifically, +the BHB might be shared across privilege levels even in the presence of +Enhanced IBRS. + +Currently the only known real-world BHB attack vector is via +unprivileged eBPF. Therefore, it's highly recommended to not enable +unprivileged eBPF, especially when eIBRS is used (without retpolines). +For a full mitigation against BHB attacks, it's recommended to use +retpolines (or eIBRS combined with retpolines). + Attack scenarios ---------------- =20 @@ -364,13 +377,15 @@ The possible values in this file are: =20 - Kernel status: =20 - =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D - 'Not affected' The processor is not vulnerable - 'Vulnerable' Vulnerable, no mitigation - 'Mitigation: Full generic retpoline' Software-focused mitigation - 'Mitigation: Full AMD retpoline' AMD-specific software mitigation - 'Mitigation: Enhanced IBRS' Hardware-focused mitigation - =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D + =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D =3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D + 'Not affected' The processor is not vulnerable + 'Mitigation: None' Vulnerable, no mitigation + 'Mitigation: Retpolines' Use Retpoline thunks + 'Mitigation: LFENCE' Use LFENCE instructions + 'Mitigation: Enhanced IBRS' Hardware-focused mitigation + 'Mitigation: Enhanced IBRS + Retpolines' Hardware-focused + Retpolines + 'Mitigation: Enhanced IBRS + LFENCE' Hardware-focused + LFENCE + =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D =3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D =20 - Firmware status: Show if Indirect Branch Restricted Speculation (IBRS)= is used to protect against Spectre variant 2 attacks when calling firmwar= e (x86 only). @@ -584,12 +599,13 @@ kernel command line. =20 Specific mitigations can also be selected manually: =20 - retpoline - replace indirect branches - retpoline,generic - google's original retpoline - retpoline,amd - AMD-specific minimal thunk + retpoline auto pick between generic,lfence + retpoline,generic Retpolines + retpoline,lfence LFENCE; indirect branch + retpoline,amd alias for retpoline,lfence + eibrs enhanced IBRS + eibrs,retpoline enhanced IBRS + Retpolines + eibrs,lfence enhanced IBRS + LFENCE =20 Not specifying this option is equivalent to spectre_v2=3Dauto. --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -4150,8 +4150,12 @@ Specific mitigations can also be selected manually: =20 retpoline - replace indirect branches - retpoline,generic - google's original retpoline - retpoline,amd - AMD-specific minimal thunk + retpoline,generic - Retpolines + retpoline,lfence - LFENCE; indirect branch + retpoline,amd - alias for retpoline,lfence + eibrs - enhanced IBRS + eibrs,retpoline - enhanced IBRS + Retpolines + eibrs,lfence - enhanced IBRS + LFENCE =20 Not specifying this option is equivalent to spectre_v2=3Dauto. From nobody Tue Jun 23 05:03:32 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 30AD3C433EF for ; Thu, 10 Mar 2022 14:30:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243963AbiCJO2H (ORCPT ); Thu, 10 Mar 2022 09:28:07 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57430 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243767AbiCJOZO (ORCPT ); Thu, 10 Mar 2022 09:25:14 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CEAAE15F35C; Thu, 10 Mar 2022 06:21:52 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 1EAC2B81E9E; Thu, 10 Mar 2022 14:21:35 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 64B9AC340E8; Thu, 10 Mar 2022 14:21:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1646922093; bh=mLE+SPjQEGdARUuUNecvyRHyXE7Tph/DLQD0FBJQkBs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ZmWE/9Zaywc8aTisGDYg2T4SglFd4W18oeO24EmCwUI8ju/f17FjP73nUUU9aMBwv UHFDv7SiY7QTmNLyovzfdbVhkeWHQ2itQnR8nsd56wvuAqBMUAQoUgA8P/zDAejA40 gzVXn8wdwSUrDWX2k/gU/CqhcEip0XYWfUUi6quU= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Josh Poimboeuf , Borislav Petkov , Thomas Gleixner , Frank van der Linden Subject: [PATCH 4.14 06/31] x86/speculation: Include unprivileged eBPF status in Spectre v2 mitigation reporting Date: Thu, 10 Mar 2022 15:18:19 +0100 Message-Id: <20220310140807.717540592@linuxfoundation.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220310140807.524313448@linuxfoundation.org> References: <20220310140807.524313448@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: Josh Poimboeuf commit 44a3918c8245ab10c6c9719dd12e7a8d291980d8 upstream. With unprivileged eBPF enabled, eIBRS (without retpoline) is vulnerable to Spectre v2 BHB-based attacks. When both are enabled, print a warning message and report it in the 'spectre_v2' sysfs vulnerabilities file. Signed-off-by: Josh Poimboeuf Signed-off-by: Borislav Petkov Reviewed-by: Thomas Gleixner [fllinden@amazon.com: backported to 4.14] Signed-off-by: Frank van der Linden Signed-off-by: Greg Kroah-Hartman Tested-by: Guenter Roeck Tested-by: Linux Kernel Functional Testing --- arch/x86/kernel/cpu/bugs.c | 35 +++++++++++++++++++++++++++++------ include/linux/bpf.h | 11 +++++++++++ kernel/sysctl.c | 8 ++++++++ 3 files changed, 48 insertions(+), 6 deletions(-) --- a/arch/x86/kernel/cpu/bugs.c +++ b/arch/x86/kernel/cpu/bugs.c @@ -31,6 +31,7 @@ #include #include #include +#include =20 #include "cpu.h" =20 @@ -607,6 +608,16 @@ static inline const char *spectre_v2_mod static inline const char *spectre_v2_module_string(void) { return ""; } #endif =20 +#define SPECTRE_V2_EIBRS_EBPF_MSG "WARNING: Unprivileged eBPF is enabled w= ith eIBRS on, data leaks possible via Spectre v2 BHB attacks!\n" + +#ifdef CONFIG_BPF_SYSCALL +void unpriv_ebpf_notify(int new_state) +{ + if (spectre_v2_enabled =3D=3D SPECTRE_V2_EIBRS && !new_state) + pr_err(SPECTRE_V2_EIBRS_EBPF_MSG); +} +#endif + static inline bool match_option(const char *arg, int arglen, const char *o= pt) { int len =3D strlen(opt); @@ -950,6 +961,9 @@ static void __init spectre_v2_select_mit break; } =20 + if (mode =3D=3D SPECTRE_V2_EIBRS && unprivileged_ebpf_enabled()) + pr_err(SPECTRE_V2_EIBRS_EBPF_MSG); + if (spectre_v2_in_eibrs_mode(mode)) { /* Force it so VMEXIT will restore correctly */ x86_spec_ctrl_base |=3D SPEC_CTRL_IBRS; @@ -1685,6 +1699,20 @@ static char *ibpb_state(void) return ""; } =20 +static ssize_t spectre_v2_show_state(char *buf) +{ + if (spectre_v2_enabled =3D=3D SPECTRE_V2_EIBRS && unprivileged_ebpf_enabl= ed()) + return sprintf(buf, "Vulnerable: Unprivileged eBPF enabled\n"); + + return sprintf(buf, "%s%s%s%s%s%s\n", + spectre_v2_strings[spectre_v2_enabled], + ibpb_state(), + boot_cpu_has(X86_FEATURE_USE_IBRS_FW) ? ", IBRS_FW" : "", + stibp_state(), + boot_cpu_has(X86_FEATURE_RSB_CTXSW) ? ", RSB filling" : "", + spectre_v2_module_string()); +} + static ssize_t srbds_show_state(char *buf) { return sprintf(buf, "%s\n", srbds_strings[srbds_mitigation]); @@ -1707,12 +1735,7 @@ static ssize_t cpu_show_common(struct de return sprintf(buf, "%s\n", spectre_v1_strings[spectre_v1_mitigation]); =20 case X86_BUG_SPECTRE_V2: - return sprintf(buf, "%s%s%s%s%s%s\n", spectre_v2_strings[spectre_v2_enab= led], - ibpb_state(), - boot_cpu_has(X86_FEATURE_USE_IBRS_FW) ? ", IBRS_FW" : "", - stibp_state(), - boot_cpu_has(X86_FEATURE_RSB_CTXSW) ? ", RSB filling" : "", - spectre_v2_module_string()); + return spectre_v2_show_state(buf); =20 case X86_BUG_SPEC_STORE_BYPASS: return sprintf(buf, "%s\n", ssb_strings[ssb_mode]); --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -337,6 +337,11 @@ static inline int bpf_map_attr_numa_node attr->numa_node : NUMA_NO_NODE; } =20 +static inline bool unprivileged_ebpf_enabled(void) +{ + return !sysctl_unprivileged_bpf_disabled; +} + #else static inline struct bpf_prog *bpf_prog_get(u32 ufd) { @@ -400,6 +405,12 @@ static inline void __dev_map_insert_ctx( static inline void __dev_map_flush(struct bpf_map *map) { } + +static inline bool unprivileged_ebpf_enabled(void) +{ + return false; +} + #endif /* CONFIG_BPF_SYSCALL */ =20 #if defined(CONFIG_STREAM_PARSER) && defined(CONFIG_BPF_SYSCALL) --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -243,6 +243,11 @@ static int sysrq_sysctl_handler(struct c #endif =20 #ifdef CONFIG_BPF_SYSCALL + +void __weak unpriv_ebpf_notify(int new_state) +{ +} + static int bpf_unpriv_handler(struct ctl_table *table, int write, void *buffer, size_t *lenp, loff_t *ppos) { @@ -260,6 +265,9 @@ static int bpf_unpriv_handler(struct ctl return -EPERM; *(int *)table->data =3D unpriv_enable; } + + unpriv_ebpf_notify(unpriv_enable); + return ret; } #endif From nobody Tue Jun 23 05:03:32 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4674FC4332F for ; Thu, 10 Mar 2022 14:30:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S244009AbiCJO2K (ORCPT ); Thu, 10 Mar 2022 09:28:10 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58462 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243507AbiCJOZV (ORCPT ); Thu, 10 Mar 2022 09:25:21 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D6D37163D6F; Thu, 10 Mar 2022 06:21:57 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 0BA19B82615; Thu, 10 Mar 2022 14:21:38 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 49BE8C340E8; Thu, 10 Mar 2022 14:21:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1646922096; bh=rSTOUX5LUvBCX6WBogDAqooyuvYNrP66hsRf3uWRExc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=etQWfusepoaDPgs89qzff3MGdp9mz4jVA1Y+e28o8VcM2+eX8I0jenvb6A2BG0R+j e6mNIviKxr4tav9YAmVdxF1rqUonLB8R4eCTsLAX0ZvU6Y2WPmtRkcOqTVhYF7a1oC 1ky7JlIi4rvkwOfkmmE5Cc4jLk1o45SC+nzTakMk= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Kim Phillips , Borislav Petkov Subject: [PATCH 4.14 07/31] x86/speculation: Use generic retpoline by default on AMD Date: Thu, 10 Mar 2022 15:18:20 +0100 Message-Id: <20220310140807.747262309@linuxfoundation.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220310140807.524313448@linuxfoundation.org> References: <20220310140807.524313448@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: Kim Phillips commit 244d00b5dd4755f8df892c86cab35fb2cfd4f14b upstream. AMD retpoline may be susceptible to speculation. The speculation execution window for an incorrect indirect branch prediction using LFENCE/JMP sequence may potentially be large enough to allow exploitation using Spectre V2. By default, don't use retpoline,lfence on AMD. Instead, use the generic retpoline. Signed-off-by: Kim Phillips Signed-off-by: Borislav Petkov Signed-off-by: Greg Kroah-Hartman Tested-by: Guenter Roeck Tested-by: Linux Kernel Functional Testing --- arch/x86/kernel/cpu/bugs.c | 8 -------- 1 file changed, 8 deletions(-) --- a/arch/x86/kernel/cpu/bugs.c +++ b/arch/x86/kernel/cpu/bugs.c @@ -898,14 +898,6 @@ static enum spectre_v2_mitigation __init return SPECTRE_V2_NONE; } =20 - if (boot_cpu_data.x86_vendor =3D=3D X86_VENDOR_AMD) { - if (!boot_cpu_has(X86_FEATURE_LFENCE_RDTSC)) { - pr_err("LFENCE not serializing, switching to generic retpoline\n"); - return SPECTRE_V2_RETPOLINE; - } - return SPECTRE_V2_LFENCE; - } - return SPECTRE_V2_RETPOLINE; } From nobody Tue Jun 23 05:03:32 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id D49D7C41535 for ; Thu, 10 Mar 2022 14:30:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S244300AbiCJO2p (ORCPT ); Thu, 10 Mar 2022 09:28:45 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58502 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243449AbiCJOZ3 (ORCPT ); Thu, 10 Mar 2022 09:25:29 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 27E8B164D1E; Thu, 10 Mar 2022 06:22:00 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 7613461CF0; Thu, 10 Mar 2022 14:21:40 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5A44EC340E8; Thu, 10 Mar 2022 14:21:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1646922099; bh=wBLb1JgeLGCmIlJRSZ+nBqsfFArPm7x3PghLmULm8JI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=x8qjqkDInkyjbcI6kLsrI+zQI5413+4DWpE86yK4s0a7FcqXFrzwchyyT3zMBuEUo mDrX26qFA5povs9YpPSSfzIB6rUR1EiZ46Wny9OloGx+pzjuLhJ8KuQt+hMYbwLYvX wxVaPyt2+BJBLr66vwDv890RmoY1Bwn/S5KyB0M0= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Kim Phillips , Borislav Petkov Subject: [PATCH 4.14 08/31] x86/speculation: Update link to AMD speculation whitepaper Date: Thu, 10 Mar 2022 15:18:21 +0100 Message-Id: <20220310140807.776338487@linuxfoundation.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220310140807.524313448@linuxfoundation.org> References: <20220310140807.524313448@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: Kim Phillips commit e9b6013a7ce31535b04b02ba99babefe8a8599fa upstream. Update the link to the "Software Techniques for Managing Speculation on AMD Processors" whitepaper. Signed-off-by: Kim Phillips Signed-off-by: Borislav Petkov Signed-off-by: Greg Kroah-Hartman Tested-by: Guenter Roeck Tested-by: Linux Kernel Functional Testing --- Documentation/admin-guide/hw-vuln/spectre.rst | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) --- a/Documentation/admin-guide/hw-vuln/spectre.rst +++ b/Documentation/admin-guide/hw-vuln/spectre.rst @@ -60,8 +60,8 @@ privileged data touched during the specu Spectre variant 1 attacks take advantage of speculative execution of conditional branches, while Spectre variant 2 attacks use speculative execution of indirect branches to leak privileged memory. -See :ref:`[1] ` :ref:`[5] ` :ref:`[7] ` -:ref:`[10] ` :ref:`[11] `. +See :ref:`[1] ` :ref:`[5] ` :ref:`[6] ` +:ref:`[7] ` :ref:`[10] ` :ref:`[11] `. =20 Spectre variant 1 (Bounds Check Bypass) --------------------------------------- @@ -746,7 +746,7 @@ AMD white papers: =20 .. _spec_ref6: =20 -[6] `Software techniques for managing speculation on AMD processors `_. +[6] `Software techniques for managing speculation on AMD processors `_. =20 ARM white papers: From nobody Tue Jun 23 05:03:32 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 22D0AC433FE for ; Thu, 10 Mar 2022 14:30:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243914AbiCJO17 (ORCPT ); Thu, 10 Mar 2022 09:27:59 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57090 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243617AbiCJOZK (ORCPT ); Thu, 10 Mar 2022 09:25:10 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C54001617C8; Thu, 10 Mar 2022 06:21:46 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 66AF7B825F3; Thu, 10 Mar 2022 14:21:44 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6076EC340EB; Thu, 10 Mar 2022 14:21:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1646922103; bh=XLsp/kinIQTkJ2i0QRtYM3XMnLfGdTKwwzZbbZDHJbM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=UQMS9H0lNn7Y17O2AZ6n4HEDbtXCe+9D9sPU/fSYWSiN2XbdB4838/w2+tTPA2U8z yv/q0HI2yXc9ZjIdRCaHvuD211n9VT/K0rAlXtVv0zNCt7NjueasyTJNb8shsQPZF4 C+p4frdbHN0MDjb6uGzqj86WmEevvRUDd5M6CaLc= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Josh Poimboeuf , Borislav Petkov Subject: [PATCH 4.14 09/31] x86/speculation: Warn about Spectre v2 LFENCE mitigation Date: Thu, 10 Mar 2022 15:18:22 +0100 Message-Id: <20220310140807.805336017@linuxfoundation.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220310140807.524313448@linuxfoundation.org> References: <20220310140807.524313448@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: Josh Poimboeuf commit eafd987d4a82c7bb5aa12f0e3b4f8f3dea93e678 upstream. With: f8a66d608a3e ("x86,bugs: Unconditionally allow spectre_v2=3Dretpoline,amd= ") it became possible to enable the LFENCE "retpoline" on Intel. However, Intel doesn't recommend it, as it has some weaknesses compared to retpoline. Now AMD doesn't recommend it either. It can still be left available as a cmdline option. It's faster than retpoline but is weaker in certain scenarios -- particularly SMT, but even non-SMT may be vulnerable in some cases. So just unconditionally warn if the user requests it on the cmdline. [ bp: Massage commit message. ] Signed-off-by: Josh Poimboeuf Signed-off-by: Borislav Petkov Signed-off-by: Greg Kroah-Hartman Tested-by: Guenter Roeck Tested-by: Linux Kernel Functional Testing --- arch/x86/kernel/cpu/bugs.c | 5 +++++ 1 file changed, 5 insertions(+) --- a/arch/x86/kernel/cpu/bugs.c +++ b/arch/x86/kernel/cpu/bugs.c @@ -608,6 +608,7 @@ static inline const char *spectre_v2_mod static inline const char *spectre_v2_module_string(void) { return ""; } #endif =20 +#define SPECTRE_V2_LFENCE_MSG "WARNING: LFENCE mitigation is not recommend= ed for this CPU, data leaks possible!\n" #define SPECTRE_V2_EIBRS_EBPF_MSG "WARNING: Unprivileged eBPF is enabled w= ith eIBRS on, data leaks possible via Spectre v2 BHB attacks!\n" =20 #ifdef CONFIG_BPF_SYSCALL @@ -929,6 +930,7 @@ static void __init spectre_v2_select_mit break; =20 case SPECTRE_V2_CMD_RETPOLINE_LFENCE: + pr_err(SPECTRE_V2_LFENCE_MSG); mode =3D SPECTRE_V2_LFENCE; break; =20 @@ -1693,6 +1695,9 @@ static char *ibpb_state(void) =20 static ssize_t spectre_v2_show_state(char *buf) { + if (spectre_v2_enabled =3D=3D SPECTRE_V2_LFENCE) + return sprintf(buf, "Vulnerable: LFENCE\n"); + if (spectre_v2_enabled =3D=3D SPECTRE_V2_EIBRS && unprivileged_ebpf_enabl= ed()) return sprintf(buf, "Vulnerable: Unprivileged eBPF enabled\n"); From nobody Tue Jun 23 05:03:32 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 55B69C433F5 for ; Thu, 10 Mar 2022 14:24:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243339AbiCJOZX (ORCPT ); Thu, 10 Mar 2022 09:25:23 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56794 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243011AbiCJOVZ (ORCPT ); Thu, 10 Mar 2022 09:21:25 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C066DB18BF; Thu, 10 Mar 2022 06:20:15 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 42D9DB825A7; Thu, 10 Mar 2022 14:20:14 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id A8B49C340E8; Thu, 10 Mar 2022 14:20:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1646922013; bh=V0cfzmqwopV1PivZZMWmBcTS6Z2GRxflX2Jvc901+co=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=wSgybXwWOs0ZpUwGTlUCGVpuDGEBpCFLx8uAycHkRYgh2I3xS6g8QU4XzjWfBZDHY EGJgjTSncdAuopF4LzLDjLyUufkPffLMMtz6+pMx4SYYr0VjkLkZ0V5oND/szCAVoa trwhyXinn3g4rPgTWNFSJyAw60nWP6pFuNVGH1yI= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Alyssa Milburn , Josh Poimboeuf , Borislav Petkov Subject: [PATCH 4.14 10/31] x86/speculation: Warn about eIBRS + LFENCE + Unprivileged eBPF + SMT Date: Thu, 10 Mar 2022 15:18:23 +0100 Message-Id: <20220310140807.834122671@linuxfoundation.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220310140807.524313448@linuxfoundation.org> References: <20220310140807.524313448@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: Josh Poimboeuf commit 0de05d056afdb00eca8c7bbb0c79a3438daf700c upstream. The commit 44a3918c8245 ("x86/speculation: Include unprivileged eBPF status in Spec= tre v2 mitigation reporting") added a warning for the "eIBRS + unprivileged eBPF" combination, which has been shown to be vulnerable against Spectre v2 BHB-based attacks. However, there's no warning about the "eIBRS + LFENCE retpoline + unprivileged eBPF" combo. The LFENCE adds more protection by shortening the speculation window after a mispredicted branch. That makes an attack significantly more difficult, even with unprivileged eBPF. So at least for now the logic doesn't warn about that combination. But if you then add SMT into the mix, the SMT attack angle weakens the effectiveness of the LFENCE considerably. So extend the "eIBRS + unprivileged eBPF" warning to also include the "eIBRS + LFENCE + unprivileged eBPF + SMT" case. [ bp: Massage commit message. ] Suggested-by: Alyssa Milburn Signed-off-by: Josh Poimboeuf Signed-off-by: Borislav Petkov Signed-off-by: Greg Kroah-Hartman Tested-by: Guenter Roeck Tested-by: Linux Kernel Functional Testing --- arch/x86/kernel/cpu/bugs.c | 27 +++++++++++++++++++++++++-- 1 file changed, 25 insertions(+), 2 deletions(-) --- a/arch/x86/kernel/cpu/bugs.c +++ b/arch/x86/kernel/cpu/bugs.c @@ -610,12 +610,27 @@ static inline const char *spectre_v2_mod =20 #define SPECTRE_V2_LFENCE_MSG "WARNING: LFENCE mitigation is not recommend= ed for this CPU, data leaks possible!\n" #define SPECTRE_V2_EIBRS_EBPF_MSG "WARNING: Unprivileged eBPF is enabled w= ith eIBRS on, data leaks possible via Spectre v2 BHB attacks!\n" +#define SPECTRE_V2_EIBRS_LFENCE_EBPF_SMT_MSG "WARNING: Unprivileged eBPF i= s enabled with eIBRS+LFENCE mitigation and SMT, data leaks possible via Spe= ctre v2 BHB attacks!\n" =20 #ifdef CONFIG_BPF_SYSCALL void unpriv_ebpf_notify(int new_state) { - if (spectre_v2_enabled =3D=3D SPECTRE_V2_EIBRS && !new_state) + if (new_state) + return; + + /* Unprivileged eBPF is enabled */ + + switch (spectre_v2_enabled) { + case SPECTRE_V2_EIBRS: pr_err(SPECTRE_V2_EIBRS_EBPF_MSG); + break; + case SPECTRE_V2_EIBRS_LFENCE: + if (sched_smt_active()) + pr_err(SPECTRE_V2_EIBRS_LFENCE_EBPF_SMT_MSG); + break; + default: + break; + } } #endif =20 @@ -1075,6 +1090,10 @@ void arch_smt_update(void) { mutex_lock(&spec_ctrl_mutex); =20 + if (sched_smt_active() && unprivileged_ebpf_enabled() && + spectre_v2_enabled =3D=3D SPECTRE_V2_EIBRS_LFENCE) + pr_warn_once(SPECTRE_V2_EIBRS_LFENCE_EBPF_SMT_MSG); + switch (spectre_v2_user_stibp) { case SPECTRE_V2_USER_NONE: break; @@ -1699,7 +1718,11 @@ static ssize_t spectre_v2_show_state(cha return sprintf(buf, "Vulnerable: LFENCE\n"); =20 if (spectre_v2_enabled =3D=3D SPECTRE_V2_EIBRS && unprivileged_ebpf_enabl= ed()) - return sprintf(buf, "Vulnerable: Unprivileged eBPF enabled\n"); + return sprintf(buf, "Vulnerable: eIBRS with unprivileged eBPF\n"); + + if (sched_smt_active() && unprivileged_ebpf_enabled() && + spectre_v2_enabled =3D=3D SPECTRE_V2_EIBRS_LFENCE) + return sprintf(buf, "Vulnerable: eIBRS+LFENCE with unprivileged eBPF and= SMT\n"); =20 return sprintf(buf, "%s%s%s%s%s%s\n", spectre_v2_strings[spectre_v2_enabled], From nobody Tue Jun 23 05:03:32 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7B66CC433EF for ; Thu, 10 Mar 2022 14:24:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238694AbiCJOZ0 (ORCPT ); Thu, 10 Mar 2022 09:25:26 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56794 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243243AbiCJOVb (ORCPT ); Thu, 10 Mar 2022 09:21:31 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E831EB239C; Thu, 10 Mar 2022 06:20:19 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 8961FB81E9E; Thu, 10 Mar 2022 14:20:18 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id C686FC36AE3; Thu, 10 Mar 2022 14:20:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1646922017; bh=O/puTpS0vTBgPhZGErm9BWdP2JhT+u4Mnv+wuMe7TjM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=UkNtOStwV5/f3BnfOSlwjyvXzSwxbS0T8xWbCAIb7DAeUyNH6Dn1XJb6X3cx6/2/t 6rktkbIgEMR/RGbolPN0cHvnGYP1GLhK5/W4poDPMnxV1q2t6vb5oTphze6dv8Nu5X t1qE0Xs61204FRez85b95G5o07tC0GsN5+VGS5Kc= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Steven Price , Will Deacon , Marc Zyngier Subject: [PATCH 4.14 11/31] arm/arm64: Provide a wrapper for SMCCC 1.1 calls Date: Thu, 10 Mar 2022 15:18:24 +0100 Message-Id: <20220310140807.862784506@linuxfoundation.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220310140807.524313448@linuxfoundation.org> References: <20220310140807.524313448@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: Steven Price commit 541625ac47ce9d0835efaee0fcbaa251b0000a37 upstream. SMCCC 1.1 calls may use either HVC or SMC depending on the PSCI conduit. Rather than coding this in every call site, provide a macro which uses the correct instruction. The macro also handles the case where no conduit is configured/available returning a not supported error in res, along with returning the conduit used for the call. This allow us to remove some duplicated code and will be useful later when adding paravirtualized time hypervisor calls. Signed-off-by: Steven Price Acked-by: Will Deacon Signed-off-by: Marc Zyngier Signed-off-by: Greg Kroah-Hartman Tested-by: Guenter Roeck Tested-by: Linux Kernel Functional Testing --- include/linux/arm-smccc.h | 58 +++++++++++++++++++++++++++++++++++++++++= +++++ 1 file changed, 58 insertions(+) --- a/include/linux/arm-smccc.h +++ b/include/linux/arm-smccc.h @@ -311,5 +311,63 @@ asmlinkage void __arm_smccc_hvc(unsigned #define SMCCC_RET_NOT_SUPPORTED -1 #define SMCCC_RET_NOT_REQUIRED -2 =20 +/* + * Like arm_smccc_1_1* but always returns SMCCC_RET_NOT_SUPPORTED. + * Used when the SMCCC conduit is not defined. The empty asm statement + * avoids compiler warnings about unused variables. + */ +#define __fail_smccc_1_1(...) \ + do { \ + __declare_args(__count_args(__VA_ARGS__), __VA_ARGS__); \ + asm ("" __constraints(__count_args(__VA_ARGS__))); \ + if (___res) \ + ___res->a0 =3D SMCCC_RET_NOT_SUPPORTED; \ + } while (0) + +/* + * arm_smccc_1_1_invoke() - make an SMCCC v1.1 compliant call + * + * This is a variadic macro taking one to eight source arguments, and + * an optional return structure. + * + * @a0-a7: arguments passed in registers 0 to 7 + * @res: result values from registers 0 to 3 + * + * This macro will make either an HVC call or an SMC call depending on the + * current SMCCC conduit. If no valid conduit is available then -1 + * (SMCCC_RET_NOT_SUPPORTED) is returned in @res.a0 (if supplied). + * + * The return value also provides the conduit that was used. + */ +#define arm_smccc_1_1_invoke(...) ({ \ + int method =3D arm_smccc_1_1_get_conduit(); \ + switch (method) { \ + case SMCCC_CONDUIT_HVC: \ + arm_smccc_1_1_hvc(__VA_ARGS__); \ + break; \ + case SMCCC_CONDUIT_SMC: \ + arm_smccc_1_1_smc(__VA_ARGS__); \ + break; \ + default: \ + __fail_smccc_1_1(__VA_ARGS__); \ + method =3D SMCCC_CONDUIT_NONE; \ + break; \ + } \ + method; \ + }) + +/* Paravirtualised time calls (defined by ARM DEN0057A) */ +#define ARM_SMCCC_HV_PV_TIME_FEATURES \ + ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, \ + ARM_SMCCC_SMC_64, \ + ARM_SMCCC_OWNER_STANDARD_HYP, \ + 0x20) + +#define ARM_SMCCC_HV_PV_TIME_ST \ + ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, \ + ARM_SMCCC_SMC_64, \ + ARM_SMCCC_OWNER_STANDARD_HYP, \ + 0x21) + #endif /*__ASSEMBLY__*/ #endif /*__LINUX_ARM_SMCCC_H*/ From nobody Tue Jun 23 05:03:32 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id D7D22C433F5 for ; Thu, 10 Mar 2022 14:24:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243505AbiCJOZc (ORCPT ); Thu, 10 Mar 2022 09:25:32 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57316 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243253AbiCJOVb (ORCPT ); Thu, 10 Mar 2022 09:21:31 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 053A1B6D3A; Thu, 10 Mar 2022 06:20:21 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 94F9D61CFD; Thu, 10 Mar 2022 14:20:20 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 945DFC36AE2; Thu, 10 Mar 2022 14:20:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1646922020; bh=hgyMPXKpyrjFSr7gjjGkb1FgtZRbJo9afPZLy+xNAuM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=vCKvCEYUngvrSFjzT3tQ/u9yt9b5sZRCx2DeoxiESKXAN3DjI8w36OBBeRY5MmJkC aOLkZly8C4pGCH9LuO5npMNsQwUbs+3YPnyfoei3ucr38CDys/JWoNCPYW58oFL5UC lTBu9DTXjy9fy7/84FqqPzbWFuQUrpUo680vUJDk= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Mark Rutland , Lorenzo Pieralisi , Will Deacon , Catalin Marinas Subject: [PATCH 4.14 12/31] arm/arm64: smccc/psci: add arm_smccc_1_1_get_conduit() Date: Thu, 10 Mar 2022 15:18:25 +0100 Message-Id: <20220310140807.892834978@linuxfoundation.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220310140807.524313448@linuxfoundation.org> References: <20220310140807.524313448@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: Mark Rutland commit 6b7fe77c334ae59fed9500140e08f4f896b36871 upstream. SMCCC callers are currently amassing a collection of enums for the SMCCC conduit, and are having to dig into the PSCI driver's internals in order to figure out what to do. Let's clean this up, with common SMCCC_CONDUIT_* definitions, and an arm_smccc_1_1_get_conduit() helper that abstracts the PSCI driver's internal state. We can kill off the PSCI_CONDUIT_* definitions once we've migrated users over to the new interface. Signed-off-by: Mark Rutland Acked-by: Lorenzo Pieralisi Acked-by: Will Deacon Signed-off-by: Catalin Marinas Signed-off-by: Greg Kroah-Hartman Tested-by: Guenter Roeck Tested-by: Linux Kernel Functional Testing --- drivers/firmware/psci.c | 15 +++++++++++++++ include/linux/arm-smccc.h | 16 ++++++++++++++++ 2 files changed, 31 insertions(+) --- a/drivers/firmware/psci.c +++ b/drivers/firmware/psci.c @@ -64,6 +64,21 @@ struct psci_operations psci_ops =3D { .smccc_version =3D SMCCC_VERSION_1_0, }; =20 +enum arm_smccc_conduit arm_smccc_1_1_get_conduit(void) +{ + if (psci_ops.smccc_version < SMCCC_VERSION_1_1) + return SMCCC_CONDUIT_NONE; + + switch (psci_ops.conduit) { + case PSCI_CONDUIT_SMC: + return SMCCC_CONDUIT_SMC; + case PSCI_CONDUIT_HVC: + return SMCCC_CONDUIT_HVC; + default: + return SMCCC_CONDUIT_NONE; + } +} + typedef unsigned long (psci_fn)(unsigned long, unsigned long, unsigned long, unsigned long); static psci_fn *invoke_psci_fn; --- a/include/linux/arm-smccc.h +++ b/include/linux/arm-smccc.h @@ -89,6 +89,22 @@ =20 #include #include + +enum arm_smccc_conduit { + SMCCC_CONDUIT_NONE, + SMCCC_CONDUIT_SMC, + SMCCC_CONDUIT_HVC, +}; + +/** + * arm_smccc_1_1_get_conduit() + * + * Returns the conduit to be used for SMCCCv1.1 or later. + * + * When SMCCCv1.1 is not present, returns SMCCC_CONDUIT_NONE. + */ +enum arm_smccc_conduit arm_smccc_1_1_get_conduit(void); + /** * struct arm_smccc_res - Result from SMC/HVC call * @a0-a3 result values from registers 0 to 3 From nobody Tue Jun 23 05:03:32 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id D2EEDC433F5 for ; Thu, 10 Mar 2022 14:24:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241866AbiCJOZk (ORCPT ); Thu, 10 Mar 2022 09:25:40 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57360 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243297AbiCJOVg (ORCPT ); Thu, 10 Mar 2022 09:21:36 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id ECF5AB82EA; Thu, 10 Mar 2022 06:20:24 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id B820461D00; Thu, 10 Mar 2022 14:20:23 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id CAF20C340E8; Thu, 10 Mar 2022 14:20:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1646922023; bh=zgbSskZyek2/0aDBCozaP6two+Rc50gvBX0vhr4LEkY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=mbi6AsDz/FAYckidzRymjXTeL3j644b8aBcUWCuwB1ktjhJYYpby8FRpDtv9Pzivc NTINFjUnzzyTg+oWyQtAeJ+px1GnTp6tuRxGmDWAipxtp+CKRjzfNe48Q/qA5HnMng 7+PsGtRj/FOb4kQjD0bSrg7D401dDLevoqxYeuW0= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Catalin Marinas , "Russell King (Oracle)" Subject: [PATCH 4.14 13/31] ARM: report Spectre v2 status through sysfs Date: Thu, 10 Mar 2022 15:18:26 +0100 Message-Id: <20220310140807.922008715@linuxfoundation.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220310140807.524313448@linuxfoundation.org> References: <20220310140807.524313448@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: "Russell King (Oracle)" commit 9dd78194a3722fa6712192cdd4f7032d45112a9a upstream. As per other architectures, add support for reporting the Spectre vulnerability status via sysfs CPU. Acked-by: Catalin Marinas Signed-off-by: Russell King (Oracle) [ preserve res variable and add SMCCC_ARCH_WORKAROUND_RET_UNAFFECTED - greg= kh ] Signed-off-by: Greg Kroah-Hartman Tested-by: Guenter Roeck Tested-by: Linux Kernel Functional Testing --- arch/arm/include/asm/spectre.h | 28 ++++++++ arch/arm/kernel/Makefile | 2=20 arch/arm/kernel/spectre.c | 54 +++++++++++++++++ arch/arm/mm/Kconfig | 1=20 arch/arm/mm/proc-v7-bugs.c | 130 +++++++++++++++++++++++++++++++-----= ----- 5 files changed, 184 insertions(+), 31 deletions(-) create mode 100644 arch/arm/include/asm/spectre.h create mode 100644 arch/arm/kernel/spectre.c --- /dev/null +++ b/arch/arm/include/asm/spectre.h @@ -0,0 +1,28 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ + +#ifndef __ASM_SPECTRE_H +#define __ASM_SPECTRE_H + +enum { + SPECTRE_UNAFFECTED, + SPECTRE_MITIGATED, + SPECTRE_VULNERABLE, +}; + +enum { + __SPECTRE_V2_METHOD_BPIALL, + __SPECTRE_V2_METHOD_ICIALLU, + __SPECTRE_V2_METHOD_SMC, + __SPECTRE_V2_METHOD_HVC, +}; + +enum { + SPECTRE_V2_METHOD_BPIALL =3D BIT(__SPECTRE_V2_METHOD_BPIALL), + SPECTRE_V2_METHOD_ICIALLU =3D BIT(__SPECTRE_V2_METHOD_ICIALLU), + SPECTRE_V2_METHOD_SMC =3D BIT(__SPECTRE_V2_METHOD_SMC), + SPECTRE_V2_METHOD_HVC =3D BIT(__SPECTRE_V2_METHOD_HVC), +}; + +void spectre_v2_update_state(unsigned int state, unsigned int methods); + +#endif --- a/arch/arm/kernel/Makefile +++ b/arch/arm/kernel/Makefile @@ -101,4 +101,6 @@ endif =20 obj-$(CONFIG_HAVE_ARM_SMCCC) +=3D smccc-call.o =20 +obj-$(CONFIG_GENERIC_CPU_VULNERABILITIES) +=3D spectre.o + extra-y :=3D $(head-y) vmlinux.lds --- /dev/null +++ b/arch/arm/kernel/spectre.c @@ -0,0 +1,54 @@ +// SPDX-License-Identifier: GPL-2.0-only +#include +#include + +#include + +ssize_t cpu_show_spectre_v1(struct device *dev, struct device_attribute *a= ttr, + char *buf) +{ + return sprintf(buf, "Mitigation: __user pointer sanitization\n"); +} + +static unsigned int spectre_v2_state; +static unsigned int spectre_v2_methods; + +void spectre_v2_update_state(unsigned int state, unsigned int method) +{ + if (state > spectre_v2_state) + spectre_v2_state =3D state; + spectre_v2_methods |=3D method; +} + +ssize_t cpu_show_spectre_v2(struct device *dev, struct device_attribute *a= ttr, + char *buf) +{ + const char *method; + + if (spectre_v2_state =3D=3D SPECTRE_UNAFFECTED) + return sprintf(buf, "%s\n", "Not affected"); + + if (spectre_v2_state !=3D SPECTRE_MITIGATED) + return sprintf(buf, "%s\n", "Vulnerable"); + + switch (spectre_v2_methods) { + case SPECTRE_V2_METHOD_BPIALL: + method =3D "Branch predictor hardening"; + break; + + case SPECTRE_V2_METHOD_ICIALLU: + method =3D "I-cache invalidation"; + break; + + case SPECTRE_V2_METHOD_SMC: + case SPECTRE_V2_METHOD_HVC: + method =3D "Firmware call"; + break; + + default: + method =3D "Multiple mitigations"; + break; + } + + return sprintf(buf, "Mitigation: %s\n", method); +} --- a/arch/arm/mm/Kconfig +++ b/arch/arm/mm/Kconfig @@ -829,6 +829,7 @@ config CPU_BPREDICT_DISABLE =20 config CPU_SPECTRE bool + select GENERIC_CPU_VULNERABILITIES =20 config HARDEN_BRANCH_PREDICTOR bool "Harden the branch predictor against aliasing attacks" if EXPERT --- a/arch/arm/mm/proc-v7-bugs.c +++ b/arch/arm/mm/proc-v7-bugs.c @@ -7,8 +7,36 @@ #include #include #include +#include #include =20 +#ifdef CONFIG_ARM_PSCI +#define SMCCC_ARCH_WORKAROUND_RET_UNAFFECTED 1 +static int __maybe_unused spectre_v2_get_cpu_fw_mitigation_state(void) +{ + struct arm_smccc_res res; + + arm_smccc_1_1_invoke(ARM_SMCCC_ARCH_FEATURES_FUNC_ID, + ARM_SMCCC_ARCH_WORKAROUND_1, &res); + + switch ((int)res.a0) { + case SMCCC_RET_SUCCESS: + return SPECTRE_MITIGATED; + + case SMCCC_ARCH_WORKAROUND_RET_UNAFFECTED: + return SPECTRE_UNAFFECTED; + + default: + return SPECTRE_VULNERABLE; + } +} +#else +static int __maybe_unused spectre_v2_get_cpu_fw_mitigation_state(void) +{ + return SPECTRE_VULNERABLE; +} +#endif + #ifdef CONFIG_HARDEN_BRANCH_PREDICTOR DEFINE_PER_CPU(harden_branch_predictor_fn_t, harden_branch_predictor_fn); =20 @@ -37,13 +65,60 @@ static void __maybe_unused call_hvc_arch arm_smccc_1_1_hvc(ARM_SMCCC_ARCH_WORKAROUND_1, NULL); } =20 -static void cpu_v7_spectre_init(void) +static unsigned int spectre_v2_install_workaround(unsigned int method) { const char *spectre_v2_method =3D NULL; int cpu =3D smp_processor_id(); =20 if (per_cpu(harden_branch_predictor_fn, cpu)) - return; + return SPECTRE_MITIGATED; + + switch (method) { + case SPECTRE_V2_METHOD_BPIALL: + per_cpu(harden_branch_predictor_fn, cpu) =3D + harden_branch_predictor_bpiall; + spectre_v2_method =3D "BPIALL"; + break; + + case SPECTRE_V2_METHOD_ICIALLU: + per_cpu(harden_branch_predictor_fn, cpu) =3D + harden_branch_predictor_iciallu; + spectre_v2_method =3D "ICIALLU"; + break; + + case SPECTRE_V2_METHOD_HVC: + per_cpu(harden_branch_predictor_fn, cpu) =3D + call_hvc_arch_workaround_1; + cpu_do_switch_mm =3D cpu_v7_hvc_switch_mm; + spectre_v2_method =3D "hypervisor"; + break; + + case SPECTRE_V2_METHOD_SMC: + per_cpu(harden_branch_predictor_fn, cpu) =3D + call_smc_arch_workaround_1; + cpu_do_switch_mm =3D cpu_v7_smc_switch_mm; + spectre_v2_method =3D "firmware"; + break; + } + + if (spectre_v2_method) + pr_info("CPU%u: Spectre v2: using %s workaround\n", + smp_processor_id(), spectre_v2_method); + + return SPECTRE_MITIGATED; +} +#else +static unsigned int spectre_v2_install_workaround(unsigned int method) +{ + pr_info("CPU%u: Spectre V2: workarounds disabled by configuration\n"); + + return SPECTRE_VULNERABLE; +} +#endif + +static void cpu_v7_spectre_v2_init(void) +{ + unsigned int state, method =3D 0; =20 switch (read_cpuid_part()) { case ARM_CPU_PART_CORTEX_A8: @@ -52,29 +127,32 @@ static void cpu_v7_spectre_init(void) case ARM_CPU_PART_CORTEX_A17: case ARM_CPU_PART_CORTEX_A73: case ARM_CPU_PART_CORTEX_A75: - per_cpu(harden_branch_predictor_fn, cpu) =3D - harden_branch_predictor_bpiall; - spectre_v2_method =3D "BPIALL"; + state =3D SPECTRE_MITIGATED; + method =3D SPECTRE_V2_METHOD_BPIALL; break; =20 case ARM_CPU_PART_CORTEX_A15: case ARM_CPU_PART_BRAHMA_B15: - per_cpu(harden_branch_predictor_fn, cpu) =3D - harden_branch_predictor_iciallu; - spectre_v2_method =3D "ICIALLU"; + state =3D SPECTRE_MITIGATED; + method =3D SPECTRE_V2_METHOD_ICIALLU; break; =20 -#ifdef CONFIG_ARM_PSCI default: /* Other ARM CPUs require no workaround */ - if (read_cpuid_implementor() =3D=3D ARM_CPU_IMP_ARM) + if (read_cpuid_implementor() =3D=3D ARM_CPU_IMP_ARM) { + state =3D SPECTRE_UNAFFECTED; break; + } /* fallthrough */ - /* Cortex A57/A72 require firmware workaround */ + /* Cortex A57/A72 require firmware workaround */ case ARM_CPU_PART_CORTEX_A57: case ARM_CPU_PART_CORTEX_A72: { struct arm_smccc_res res; =20 + state =3D spectre_v2_get_cpu_fw_mitigation_state(); + if (state !=3D SPECTRE_MITIGATED) + break; + if (psci_ops.smccc_version =3D=3D SMCCC_VERSION_1_0) break; =20 @@ -84,10 +162,7 @@ static void cpu_v7_spectre_init(void) ARM_SMCCC_ARCH_WORKAROUND_1, &res); if ((int)res.a0 !=3D 0) break; - per_cpu(harden_branch_predictor_fn, cpu) =3D - call_hvc_arch_workaround_1; - cpu_do_switch_mm =3D cpu_v7_hvc_switch_mm; - spectre_v2_method =3D "hypervisor"; + method =3D SPECTRE_V2_METHOD_HVC; break; =20 case PSCI_CONDUIT_SMC: @@ -95,28 +170,21 @@ static void cpu_v7_spectre_init(void) ARM_SMCCC_ARCH_WORKAROUND_1, &res); if ((int)res.a0 !=3D 0) break; - per_cpu(harden_branch_predictor_fn, cpu) =3D - call_smc_arch_workaround_1; - cpu_do_switch_mm =3D cpu_v7_smc_switch_mm; - spectre_v2_method =3D "firmware"; + method =3D SPECTRE_V2_METHOD_SMC; break; =20 default: + state =3D SPECTRE_VULNERABLE; break; } } -#endif } =20 - if (spectre_v2_method) - pr_info("CPU%u: Spectre v2: using %s workaround\n", - smp_processor_id(), spectre_v2_method); -} -#else -static void cpu_v7_spectre_init(void) -{ + if (state =3D=3D SPECTRE_MITIGATED) + state =3D spectre_v2_install_workaround(method); + + spectre_v2_update_state(state, method); } -#endif =20 static __maybe_unused bool cpu_v7_check_auxcr_set(bool *warned, u32 mask, const char *msg) @@ -146,16 +214,16 @@ static bool check_spectre_auxcr(bool *wa void cpu_v7_ca8_ibe(void) { if (check_spectre_auxcr(this_cpu_ptr(&spectre_warned), BIT(6))) - cpu_v7_spectre_init(); + cpu_v7_spectre_v2_init(); } =20 void cpu_v7_ca15_ibe(void) { if (check_spectre_auxcr(this_cpu_ptr(&spectre_warned), BIT(0))) - cpu_v7_spectre_init(); + cpu_v7_spectre_v2_init(); } =20 void cpu_v7_bugs_init(void) { - cpu_v7_spectre_init(); + cpu_v7_spectre_v2_init(); } From nobody Tue Jun 23 05:03:32 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id AAACBC433EF for ; Thu, 10 Mar 2022 14:24:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241948AbiCJOZs (ORCPT ); Thu, 10 Mar 2022 09:25:48 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58412 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243324AbiCJOVn (ORCPT ); Thu, 10 Mar 2022 09:21:43 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BEEB7BECCE; Thu, 10 Mar 2022 06:20:29 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id E9DB8B825F3; Thu, 10 Mar 2022 14:20:27 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5CB3FC340E8; Thu, 10 Mar 2022 14:20:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1646922026; bh=Yry5MStUl6kJVX6ddF24JcfhvBWe69QvcUTxAvEtDK8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=c/cDdQM34iD/PaueVPmwm4+HsjaLaUD5HhWRJx9tLixkzftFe7E5k0lQYHBSupcfL JwkyRRULYgK3zQz4n6rrQ3j95BJr0Pl70EToxiGvZb4J0uuT+G2XPKfa+mKrKXthIC 6tJdG2sbeUFUTUn1sEqlGOIIWO6MVR273QooOaZo= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Catalin Marinas , "Russell King (Oracle)" Subject: [PATCH 4.14 14/31] ARM: early traps initialisation Date: Thu, 10 Mar 2022 15:18:27 +0100 Message-Id: <20220310140807.951770903@linuxfoundation.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220310140807.524313448@linuxfoundation.org> References: <20220310140807.524313448@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: "Russell King (Oracle)" commit 04e91b7324760a377a725e218b5ee783826d30f5 upstream. Provide a couple of helpers to copy the vectors and stubs, and also to flush the copied vectors and stubs. Acked-by: Catalin Marinas Signed-off-by: Russell King (Oracle) Signed-off-by: Greg Kroah-Hartman Tested-by: Guenter Roeck Tested-by: Linux Kernel Functional Testing --- arch/arm/kernel/traps.c | 27 +++++++++++++++++++++------ 1 file changed, 21 insertions(+), 6 deletions(-) --- a/arch/arm/kernel/traps.c +++ b/arch/arm/kernel/traps.c @@ -820,10 +820,22 @@ static inline void __init kuser_init(voi } #endif =20 +#ifndef CONFIG_CPU_V7M +static void copy_from_lma(void *vma, void *lma_start, void *lma_end) +{ + memcpy(vma, lma_start, lma_end - lma_start); +} + +static void flush_vectors(void *vma, size_t offset, size_t size) +{ + unsigned long start =3D (unsigned long)vma + offset; + unsigned long end =3D start + size; + + flush_icache_range(start, end); +} + void __init early_trap_init(void *vectors_base) { -#ifndef CONFIG_CPU_V7M - unsigned long vectors =3D (unsigned long)vectors_base; extern char __stubs_start[], __stubs_end[]; extern char __vectors_start[], __vectors_end[]; unsigned i; @@ -844,17 +856,20 @@ void __init early_trap_init(void *vector * into the vector page, mapped at 0xffff0000, and ensure these * are visible to the instruction stream. */ - memcpy((void *)vectors, __vectors_start, __vectors_end - __vectors_start); - memcpy((void *)vectors + 0x1000, __stubs_start, __stubs_end - __stubs_sta= rt); + copy_from_lma(vectors_base, __vectors_start, __vectors_end); + copy_from_lma(vectors_base + 0x1000, __stubs_start, __stubs_end); =20 kuser_init(vectors_base); =20 - flush_icache_range(vectors, vectors + PAGE_SIZE * 2); + flush_vectors(vectors_base, 0, PAGE_SIZE * 2); +} #else /* ifndef CONFIG_CPU_V7M */ +void __init early_trap_init(void *vectors_base) +{ /* * on V7-M there is no need to copy the vector table to a dedicated * memory area. The address is configurable and so a table in the kernel * image can be used. */ -#endif } +#endif From nobody Tue Jun 23 05:03:32 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id C5D66C433FE for ; Thu, 10 Mar 2022 14:24:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241585AbiCJOZw (ORCPT ); Thu, 10 Mar 2022 09:25:52 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57780 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243369AbiCJOVp (ORCPT ); Thu, 10 Mar 2022 09:21:45 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5D2D0B250C; Thu, 10 Mar 2022 06:20:32 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id EEEF2B82670; Thu, 10 Mar 2022 14:20:30 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3E5AAC340EB; Thu, 10 Mar 2022 14:20:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1646922029; bh=Yd5n5DSjjVDG87tEbvo0EgJLSt9bMab9/62XTFXxw2s=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=UYAulTbk672MnC19J11fdrM8FQFV8jUTHRWv0OsphYQoUPGskJ24NLcCQ3fWeZxG6 e8Y5Z+nfhWqm8JEMWoKJ7ORRkQ8QfH9eI2JEVT6lCGbBnakYdRbj4CwvW7Rs3+2zpR 7tWbdayWaYneJPGwufqh85FNTaN+XRs9z8E8j650= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Catalin Marinas , "Russell King (Oracle)" Subject: [PATCH 4.14 15/31] ARM: use LOADADDR() to get load address of sections Date: Thu, 10 Mar 2022 15:18:28 +0100 Message-Id: <20220310140807.979965576@linuxfoundation.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220310140807.524313448@linuxfoundation.org> References: <20220310140807.524313448@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: "Russell King (Oracle)" commit 8d9d651ff2270a632e9dc497b142db31e8911315 upstream. Use the linker's LOADADDR() macro to get the load address of the sections, and provide a macro to set the start and end symbols. Acked-by: Catalin Marinas Signed-off-by: Russell King (Oracle) Signed-off-by: Greg Kroah-Hartman Tested-by: Guenter Roeck Tested-by: Linux Kernel Functional Testing --- arch/arm/kernel/vmlinux-xip.lds.S | 19 ++++++++++++------- arch/arm/kernel/vmlinux.lds.S | 19 ++++++++++++------- 2 files changed, 24 insertions(+), 14 deletions(-) --- a/arch/arm/kernel/vmlinux-xip.lds.S +++ b/arch/arm/kernel/vmlinux-xip.lds.S @@ -13,6 +13,11 @@ #include #include =20 +/* Set start/end symbol names to the LMA for the section */ +#define ARM_LMA(sym, section) \ + sym##_start =3D LOADADDR(section); \ + sym##_end =3D LOADADDR(section) + SIZEOF(section) + #define PROC_INFO \ . =3D ALIGN(4); \ VMLINUX_SYMBOL(__proc_info_begin) =3D .; \ @@ -149,19 +154,19 @@ SECTIONS * The vectors and stubs are relocatable code, and the * only thing that matters is their relative offsets */ - __vectors_start =3D .; + __vectors_lma =3D .; .vectors 0xffff0000 : AT(__vectors_start) { *(.vectors) } - . =3D __vectors_start + SIZEOF(.vectors); - __vectors_end =3D .; + ARM_LMA(__vectors, .vectors); + . =3D __vectors_lma + SIZEOF(.vectors); =20 - __stubs_start =3D .; - .stubs ADDR(.vectors) + 0x1000 : AT(__stubs_start) { + __stubs_lma =3D .; + .stubs ADDR(.vectors) + 0x1000 : AT(__stubs_lma) { *(.stubs) } - . =3D __stubs_start + SIZEOF(.stubs); - __stubs_end =3D .; + ARM_LMA(__stubs, .stubs); + . =3D __stubs_lma + SIZEOF(.stubs); =20 PROVIDE(vector_fiq_offset =3D vector_fiq - ADDR(.vectors)); =20 --- a/arch/arm/kernel/vmlinux.lds.S +++ b/arch/arm/kernel/vmlinux.lds.S @@ -15,6 +15,11 @@ #include #include =20 +/* Set start/end symbol names to the LMA for the section */ +#define ARM_LMA(sym, section) \ + sym##_start =3D LOADADDR(section); \ + sym##_end =3D LOADADDR(section) + SIZEOF(section) + #define PROC_INFO \ . =3D ALIGN(4); \ VMLINUX_SYMBOL(__proc_info_begin) =3D .; \ @@ -170,19 +175,19 @@ SECTIONS * The vectors and stubs are relocatable code, and the * only thing that matters is their relative offsets */ - __vectors_start =3D .; + __vectors_lma =3D .; .vectors 0xffff0000 : AT(__vectors_start) { *(.vectors) } - . =3D __vectors_start + SIZEOF(.vectors); - __vectors_end =3D .; + ARM_LMA(__vectors, .vectors); + . =3D __vectors_lma + SIZEOF(.vectors); =20 - __stubs_start =3D .; - .stubs ADDR(.vectors) + 0x1000 : AT(__stubs_start) { + __stubs_lma =3D .; + .stubs ADDR(.vectors) + 0x1000 : AT(__stubs_lma) { *(.stubs) } - . =3D __stubs_start + SIZEOF(.stubs); - __stubs_end =3D .; + ARM_LMA(__stubs, .stubs); + . =3D __stubs_lma + SIZEOF(.stubs); =20 PROVIDE(vector_fiq_offset =3D vector_fiq - ADDR(.vectors)); From nobody Tue Jun 23 05:03:32 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id A09FFC433EF for ; Thu, 10 Mar 2022 14:24:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240137AbiCJOZ4 (ORCPT ); Thu, 10 Mar 2022 09:25:56 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58596 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243408AbiCJOVs (ORCPT ); Thu, 10 Mar 2022 09:21:48 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A692EB561C; Thu, 10 Mar 2022 06:20:36 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 3AC5FB82678; Thu, 10 Mar 2022 14:20:34 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6CED9C340E8; Thu, 10 Mar 2022 14:20:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1646922032; bh=zaaG9f1LUsZJAVT1xkSrbI0gFHTParhDn5YvSeBVte0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Q4cnsS7HBRl4wlQdGQpQ27juWkNDt50dHDzqacgVgFiygsP0eOJR+X9cByKCJcmdB +0i5iXidAc69xr3JFcYsVcNeFWbSUklG9/NobEWMzXJ37d7hl3O8hOwyeNAO4an190 TcjJum+IdgkdeBCnrTJRzYwPxFxZ0D6TauMs4328= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Catalin Marinas , "Russell King (Oracle)" Subject: [PATCH 4.14 16/31] ARM: Spectre-BHB workaround Date: Thu, 10 Mar 2022 15:18:29 +0100 Message-Id: <20220310140808.008882877@linuxfoundation.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220310140807.524313448@linuxfoundation.org> References: <20220310140807.524313448@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: "Russell King (Oracle)" commit b9baf5c8c5c356757f4f9d8180b5e9d234065bc3 upstream. Workaround the Spectre BHB issues for Cortex-A15, Cortex-A57, Cortex-A72, Cortex-A73 and Cortex-A75. We also include Brahma B15 as well to be safe, which is affected by Spectre V2 in the same ways as Cortex-A15. Reviewed-by: Catalin Marinas Signed-off-by: Russell King (Oracle) [changes due to lack of SYSTEM_FREEING_INITMEM - gregkh] Signed-off-by: Greg Kroah-Hartman Tested-by: Guenter Roeck Tested-by: Linux Kernel Functional Testing --- arch/arm/include/asm/assembler.h | 10 ++++ arch/arm/include/asm/spectre.h | 4 + arch/arm/kernel/entry-armv.S | 79 +++++++++++++++++++++++++++++++++= ++--- arch/arm/kernel/entry-common.S | 24 +++++++++++ arch/arm/kernel/spectre.c | 4 + arch/arm/kernel/traps.c | 38 ++++++++++++++++++ arch/arm/kernel/vmlinux-xip.lds.S | 18 +++++++- arch/arm/kernel/vmlinux.lds.S | 18 +++++++- arch/arm/mm/Kconfig | 10 ++++ arch/arm/mm/proc-v7-bugs.c | 76 +++++++++++++++++++++++++++++++++= +++ 10 files changed, 269 insertions(+), 12 deletions(-) --- a/arch/arm/include/asm/assembler.h +++ b/arch/arm/include/asm/assembler.h @@ -110,6 +110,16 @@ .endm #endif =20 +#if __LINUX_ARM_ARCH__ < 7 + .macro dsb, args + mcr p15, 0, r0, c7, c10, 4 + .endm + + .macro isb, args + mcr p15, 0, r0, c7, r5, 4 + .endm +#endif + .macro asm_trace_hardirqs_off, save=3D1 #if defined(CONFIG_TRACE_IRQFLAGS) .if \save --- a/arch/arm/include/asm/spectre.h +++ b/arch/arm/include/asm/spectre.h @@ -14,6 +14,7 @@ enum { __SPECTRE_V2_METHOD_ICIALLU, __SPECTRE_V2_METHOD_SMC, __SPECTRE_V2_METHOD_HVC, + __SPECTRE_V2_METHOD_LOOP8, }; =20 enum { @@ -21,8 +22,11 @@ enum { SPECTRE_V2_METHOD_ICIALLU =3D BIT(__SPECTRE_V2_METHOD_ICIALLU), SPECTRE_V2_METHOD_SMC =3D BIT(__SPECTRE_V2_METHOD_SMC), SPECTRE_V2_METHOD_HVC =3D BIT(__SPECTRE_V2_METHOD_HVC), + SPECTRE_V2_METHOD_LOOP8 =3D BIT(__SPECTRE_V2_METHOD_LOOP8), }; =20 void spectre_v2_update_state(unsigned int state, unsigned int methods); =20 +int spectre_bhb_update_vectors(unsigned int method); + #endif --- a/arch/arm/kernel/entry-armv.S +++ b/arch/arm/kernel/entry-armv.S @@ -1033,12 +1033,11 @@ vector_\name: sub lr, lr, #\correction .endif =20 - @ - @ Save r0, lr_ (parent PC) and spsr_ - @ (parent CPSR) - @ + @ Save r0, lr_ (parent PC) stmia sp, {r0, lr} @ save r0, lr - mrs lr, spsr + + @ Save spsr_ (parent CPSR) +2: mrs lr, spsr str lr, [sp, #8] @ save spsr =20 @ @@ -1059,6 +1058,44 @@ vector_\name: movs pc, lr @ branch to handler in SVC mode ENDPROC(vector_\name) =20 +#ifdef CONFIG_HARDEN_BRANCH_HISTORY + .subsection 1 + .align 5 +vector_bhb_loop8_\name: + .if \correction + sub lr, lr, #\correction + .endif + + @ Save r0, lr_ (parent PC) + stmia sp, {r0, lr} + + @ bhb workaround + mov r0, #8 +1: b . + 4 + subs r0, r0, #1 + bne 1b + dsb + isb + b 2b +ENDPROC(vector_bhb_loop8_\name) + +vector_bhb_bpiall_\name: + .if \correction + sub lr, lr, #\correction + .endif + + @ Save r0, lr_ (parent PC) + stmia sp, {r0, lr} + + @ bhb workaround + mcr p15, 0, r0, c7, c5, 6 @ BPIALL + @ isb not needed due to "movs pc, lr" in the vector stub + @ which gives a "context synchronisation". + b 2b +ENDPROC(vector_bhb_bpiall_\name) + .previous +#endif + .align 2 @ handler addresses follow this label 1: @@ -1067,6 +1104,10 @@ ENDPROC(vector_\name) .section .stubs, "ax", %progbits @ This must be the first word .word vector_swi +#ifdef CONFIG_HARDEN_BRANCH_HISTORY + .word vector_bhb_loop8_swi + .word vector_bhb_bpiall_swi +#endif =20 vector_rst: ARM( swi SYS_ERROR0 ) @@ -1181,8 +1222,10 @@ vector_addrexcptn: * FIQ "NMI" handler *------------------------------------------------------------------------= ----- * Handle a FIQ using the SVC stack allowing FIQ act like NMI on x86 - * systems. + * systems. This must be the last vector stub, so lets place it in its own + * subsection. */ + .subsection 2 vector_stub fiq, FIQ_MODE, 4 =20 .long __fiq_usr @ 0 (USR_26 / USR_32) @@ -1215,6 +1258,30 @@ vector_addrexcptn: W(b) vector_irq W(b) vector_fiq =20 +#ifdef CONFIG_HARDEN_BRANCH_HISTORY + .section .vectors.bhb.loop8, "ax", %progbits +.L__vectors_bhb_loop8_start: + W(b) vector_rst + W(b) vector_bhb_loop8_und + W(ldr) pc, .L__vectors_bhb_loop8_start + 0x1004 + W(b) vector_bhb_loop8_pabt + W(b) vector_bhb_loop8_dabt + W(b) vector_addrexcptn + W(b) vector_bhb_loop8_irq + W(b) vector_bhb_loop8_fiq + + .section .vectors.bhb.bpiall, "ax", %progbits +.L__vectors_bhb_bpiall_start: + W(b) vector_rst + W(b) vector_bhb_bpiall_und + W(ldr) pc, .L__vectors_bhb_bpiall_start + 0x1008 + W(b) vector_bhb_bpiall_pabt + W(b) vector_bhb_bpiall_dabt + W(b) vector_addrexcptn + W(b) vector_bhb_bpiall_irq + W(b) vector_bhb_bpiall_fiq +#endif + .data .align 2 =20 --- a/arch/arm/kernel/entry-common.S +++ b/arch/arm/kernel/entry-common.S @@ -152,12 +152,36 @@ ENDPROC(ret_from_fork) */ =20 .align 5 +#ifdef CONFIG_HARDEN_BRANCH_HISTORY +ENTRY(vector_bhb_loop8_swi) + sub sp, sp, #PT_REGS_SIZE + stmia sp, {r0 - r12} + mov r8, #8 +1: b 2f +2: subs r8, r8, #1 + bne 1b + dsb + isb + b 3f +ENDPROC(vector_bhb_loop8_swi) + + .align 5 +ENTRY(vector_bhb_bpiall_swi) + sub sp, sp, #PT_REGS_SIZE + stmia sp, {r0 - r12} + mcr p15, 0, r8, c7, c5, 6 @ BPIALL + isb + b 3f +ENDPROC(vector_bhb_bpiall_swi) +#endif + .align 5 ENTRY(vector_swi) #ifdef CONFIG_CPU_V7M v7m_exception_entry #else sub sp, sp, #PT_REGS_SIZE stmia sp, {r0 - r12} @ Calling r0 - r12 +3: ARM( add r8, sp, #S_PC ) ARM( stmdb r8, {sp, lr}^ ) @ Calling sp, lr THUMB( mov r8, sp ) --- a/arch/arm/kernel/spectre.c +++ b/arch/arm/kernel/spectre.c @@ -45,6 +45,10 @@ ssize_t cpu_show_spectre_v2(struct devic method =3D "Firmware call"; break; =20 + case SPECTRE_V2_METHOD_LOOP8: + method =3D "History overwrite"; + break; + default: method =3D "Multiple mitigations"; break; --- a/arch/arm/kernel/traps.c +++ b/arch/arm/kernel/traps.c @@ -33,6 +33,7 @@ #include #include #include +#include #include #include #include @@ -834,6 +835,43 @@ static void flush_vectors(void *vma, siz flush_icache_range(start, end); } =20 +#ifdef CONFIG_HARDEN_BRANCH_HISTORY +int spectre_bhb_update_vectors(unsigned int method) +{ + extern char __vectors_bhb_bpiall_start[], __vectors_bhb_bpiall_end[]; + extern char __vectors_bhb_loop8_start[], __vectors_bhb_loop8_end[]; + void *vec_start, *vec_end; + + if (system_state > SYSTEM_SCHEDULING) { + pr_err("CPU%u: Spectre BHB workaround too late - system vulnerable\n", + smp_processor_id()); + return SPECTRE_VULNERABLE; + } + + switch (method) { + case SPECTRE_V2_METHOD_LOOP8: + vec_start =3D __vectors_bhb_loop8_start; + vec_end =3D __vectors_bhb_loop8_end; + break; + + case SPECTRE_V2_METHOD_BPIALL: + vec_start =3D __vectors_bhb_bpiall_start; + vec_end =3D __vectors_bhb_bpiall_end; + break; + + default: + pr_err("CPU%u: unknown Spectre BHB state %d\n", + smp_processor_id(), method); + return SPECTRE_VULNERABLE; + } + + copy_from_lma(vectors_page, vec_start, vec_end); + flush_vectors(vectors_page, 0, vec_end - vec_start); + + return SPECTRE_MITIGATED; +} +#endif + void __init early_trap_init(void *vectors_base) { extern char __stubs_start[], __stubs_end[]; --- a/arch/arm/kernel/vmlinux-xip.lds.S +++ b/arch/arm/kernel/vmlinux-xip.lds.S @@ -155,11 +155,23 @@ SECTIONS * only thing that matters is their relative offsets */ __vectors_lma =3D .; - .vectors 0xffff0000 : AT(__vectors_start) { - *(.vectors) + OVERLAY 0xffff0000 : NOCROSSREFS AT(__vectors_lma) { + .vectors { + *(.vectors) + } + .vectors.bhb.loop8 { + *(.vectors.bhb.loop8) + } + .vectors.bhb.bpiall { + *(.vectors.bhb.bpiall) + } } ARM_LMA(__vectors, .vectors); - . =3D __vectors_lma + SIZEOF(.vectors); + ARM_LMA(__vectors_bhb_loop8, .vectors.bhb.loop8); + ARM_LMA(__vectors_bhb_bpiall, .vectors.bhb.bpiall); + . =3D __vectors_lma + SIZEOF(.vectors) + + SIZEOF(.vectors.bhb.loop8) + + SIZEOF(.vectors.bhb.bpiall); =20 __stubs_lma =3D .; .stubs ADDR(.vectors) + 0x1000 : AT(__stubs_lma) { --- a/arch/arm/kernel/vmlinux.lds.S +++ b/arch/arm/kernel/vmlinux.lds.S @@ -176,11 +176,23 @@ SECTIONS * only thing that matters is their relative offsets */ __vectors_lma =3D .; - .vectors 0xffff0000 : AT(__vectors_start) { - *(.vectors) + OVERLAY 0xffff0000 : NOCROSSREFS AT(__vectors_lma) { + .vectors { + *(.vectors) + } + .vectors.bhb.loop8 { + *(.vectors.bhb.loop8) + } + .vectors.bhb.bpiall { + *(.vectors.bhb.bpiall) + } } ARM_LMA(__vectors, .vectors); - . =3D __vectors_lma + SIZEOF(.vectors); + ARM_LMA(__vectors_bhb_loop8, .vectors.bhb.loop8); + ARM_LMA(__vectors_bhb_bpiall, .vectors.bhb.bpiall); + . =3D __vectors_lma + SIZEOF(.vectors) + + SIZEOF(.vectors.bhb.loop8) + + SIZEOF(.vectors.bhb.bpiall); =20 __stubs_lma =3D .; .stubs ADDR(.vectors) + 0x1000 : AT(__stubs_lma) { --- a/arch/arm/mm/Kconfig +++ b/arch/arm/mm/Kconfig @@ -850,6 +850,16 @@ config HARDEN_BRANCH_PREDICTOR =20 If unsure, say Y. =20 +config HARDEN_BRANCH_HISTORY + bool "Harden Spectre style attacks against branch history" if EXPERT + depends on CPU_SPECTRE + default y + help + Speculation attacks against some high-performance processors can + make use of branch history to influence future speculation. When + taking an exception, a sequence of branches overwrites the branch + history, or branch history is invalidated. + config TLS_REG_EMUL bool select NEED_KUSER_HELPERS --- a/arch/arm/mm/proc-v7-bugs.c +++ b/arch/arm/mm/proc-v7-bugs.c @@ -186,6 +186,81 @@ static void cpu_v7_spectre_v2_init(void) spectre_v2_update_state(state, method); } =20 +#ifdef CONFIG_HARDEN_BRANCH_HISTORY +static int spectre_bhb_method; + +static const char *spectre_bhb_method_name(int method) +{ + switch (method) { + case SPECTRE_V2_METHOD_LOOP8: + return "loop"; + + case SPECTRE_V2_METHOD_BPIALL: + return "BPIALL"; + + default: + return "unknown"; + } +} + +static int spectre_bhb_install_workaround(int method) +{ + if (spectre_bhb_method !=3D method) { + if (spectre_bhb_method) { + pr_err("CPU%u: Spectre BHB: method disagreement, system vulnerable\n", + smp_processor_id()); + + return SPECTRE_VULNERABLE; + } + + if (spectre_bhb_update_vectors(method) =3D=3D SPECTRE_VULNERABLE) + return SPECTRE_VULNERABLE; + + spectre_bhb_method =3D method; + } + + pr_info("CPU%u: Spectre BHB: using %s workaround\n", + smp_processor_id(), spectre_bhb_method_name(method)); + + return SPECTRE_MITIGATED; +} +#else +static int spectre_bhb_install_workaround(int method) +{ + return SPECTRE_VULNERABLE; +} +#endif + +static void cpu_v7_spectre_bhb_init(void) +{ + unsigned int state, method =3D 0; + + switch (read_cpuid_part()) { + case ARM_CPU_PART_CORTEX_A15: + case ARM_CPU_PART_BRAHMA_B15: + case ARM_CPU_PART_CORTEX_A57: + case ARM_CPU_PART_CORTEX_A72: + state =3D SPECTRE_MITIGATED; + method =3D SPECTRE_V2_METHOD_LOOP8; + break; + + case ARM_CPU_PART_CORTEX_A73: + case ARM_CPU_PART_CORTEX_A75: + state =3D SPECTRE_MITIGATED; + method =3D SPECTRE_V2_METHOD_BPIALL; + break; + + default: + state =3D SPECTRE_UNAFFECTED; + break; + } + + if (state =3D=3D SPECTRE_MITIGATED) + state =3D spectre_bhb_install_workaround(method); + + spectre_v2_update_state(state, method); +} + static __maybe_unused bool cpu_v7_check_auxcr_set(bool *warned, u32 mask, const char *msg) { @@ -226,4 +301,5 @@ void cpu_v7_ca15_ibe(void) void cpu_v7_bugs_init(void) { cpu_v7_spectre_v2_init(); + cpu_v7_spectre_bhb_init(); } From nobody Tue Jun 23 05:03:32 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id C3D03C433F5 for ; Thu, 10 Mar 2022 14:25:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241627AbiCJO0H (ORCPT ); Thu, 10 Mar 2022 09:26:07 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57432 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243421AbiCJOVs (ORCPT ); Thu, 10 Mar 2022 09:21:48 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 54815C2E70; Thu, 10 Mar 2022 06:20:37 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id B468E61CEE; Thu, 10 Mar 2022 14:20:36 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id C8D44C340E8; Thu, 10 Mar 2022 14:20:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1646922036; bh=YYTxn4Nwrg6CuOgCloYwoSlfT43YKOmCi0fRD30gcL8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Nmxam5bhJ2y52W/77Kw+i70hjxKmbZjpAvNVkpQy95eyrYTBoM8RS8JMkmgaD9H3M QYuoDZ1tRPqexHw2BdRnMaX1n7KGYRbOv0gMcPkOsqXhVT32CrA6l6i0Lv0MvrGmYi dKxIGP2gw0It7v9Nx5EwP32AvY3JmFDtLGY0qbDM= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, "Russell King (Oracle)" Subject: [PATCH 4.14 17/31] ARM: include unprivileged BPF status in Spectre V2 reporting Date: Thu, 10 Mar 2022 15:18:30 +0100 Message-Id: <20220310140808.037993536@linuxfoundation.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220310140807.524313448@linuxfoundation.org> References: <20220310140807.524313448@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: Russell King (Oracle) commit 25875aa71dfefd1959f07e626c4d285b88b27ac2 upstream. The mitigations for Spectre-BHB are only applied when an exception is taken, but when unprivileged BPF is enabled, userspace can load BPF programs that can be used to exploit the problem. When unprivileged BPF is enabled, report the vulnerable status via the spectre_v2 sysfs file. Signed-off-by: Russell King (Oracle) Signed-off-by: Greg Kroah-Hartman Tested-by: Guenter Roeck Tested-by: Linux Kernel Functional Testing --- arch/arm/kernel/spectre.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) --- a/arch/arm/kernel/spectre.c +++ b/arch/arm/kernel/spectre.c @@ -1,9 +1,19 @@ // SPDX-License-Identifier: GPL-2.0-only +#include #include #include =20 #include =20 +static bool _unprivileged_ebpf_enabled(void) +{ +#ifdef CONFIG_BPF_SYSCALL + return !sysctl_unprivileged_bpf_disabled; +#else + return false +#endif +} + ssize_t cpu_show_spectre_v1(struct device *dev, struct device_attribute *a= ttr, char *buf) { @@ -31,6 +41,9 @@ ssize_t cpu_show_spectre_v2(struct devic if (spectre_v2_state !=3D SPECTRE_MITIGATED) return sprintf(buf, "%s\n", "Vulnerable"); =20 + if (_unprivileged_ebpf_enabled()) + return sprintf(buf, "Vulnerable: Unprivileged eBPF enabled\n"); + switch (spectre_v2_methods) { case SPECTRE_V2_METHOD_BPIALL: method =3D "Branch predictor hardening"; From nobody Tue Jun 23 05:03:32 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id BB68BC4332F for ; Thu, 10 Mar 2022 14:25:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242810AbiCJO0Q (ORCPT ); Thu, 10 Mar 2022 09:26:16 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59036 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243299AbiCJOV6 (ORCPT ); Thu, 10 Mar 2022 09:21:58 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id F3341B4585; Thu, 10 Mar 2022 06:20:41 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 7DDDEB825F3; Thu, 10 Mar 2022 14:20:40 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id C6ED2C340E8; Thu, 10 Mar 2022 14:20:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1646922039; bh=dBM59trElM9mKdvh5X3TAf3lhidiLDUO/YzmBUoNg2U=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=WAMimDajIseW2eD/R1WNxzdhMSrjAyVl2qFZDpWKS1AC9re5MgFIhtr26jbyt2Lfv 1/9L7ESn2b9+tsG1F5jw8jop1A+iWvNKAEKX6zecL9u/1Xyj+QCwZZKnip6IH/UnGr w7ragcqIfaYKox8Y0UKhQMk6nVirBNGg+ediEmD8= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Emmanuel Gil Peyrot , Nathan Chancellor , Linus Torvalds Subject: [PATCH 4.14 18/31] ARM: fix build error when BPF_SYSCALL is disabled Date: Thu, 10 Mar 2022 15:18:31 +0100 Message-Id: <20220310140808.067420708@linuxfoundation.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220310140807.524313448@linuxfoundation.org> References: <20220310140807.524313448@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: Emmanuel Gil Peyrot commit 330f4c53d3c2d8b11d86ec03a964b86dc81452f5 upstream. It was missing a semicolon. Signed-off-by: Emmanuel Gil Peyrot Reviewed-by: Nathan Chancellor Fixes: 25875aa71dfe ("ARM: include unprivileged BPF status in Spectre V2 re= porting"). Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman Tested-by: Guenter Roeck Tested-by: Linux Kernel Functional Testing --- arch/arm/kernel/spectre.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/arch/arm/kernel/spectre.c +++ b/arch/arm/kernel/spectre.c @@ -10,7 +10,7 @@ static bool _unprivileged_ebpf_enabled(v #ifdef CONFIG_BPF_SYSCALL return !sysctl_unprivileged_bpf_disabled; #else - return false + return false; #endif } From nobody Tue Jun 23 05:03:32 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id DC00CC433F5 for ; Thu, 10 Mar 2022 14:25:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243508AbiCJO0Y (ORCPT ); Thu, 10 Mar 2022 09:26:24 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58490 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243330AbiCJOV7 (ORCPT ); Thu, 10 Mar 2022 09:21:59 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 10780EFFBB; Thu, 10 Mar 2022 06:20:43 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 9E67461CF0; Thu, 10 Mar 2022 14:20:42 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 95677C340E8; Thu, 10 Mar 2022 14:20:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1646922042; bh=+KiLqnFc/JOlPhhx2sGptnR9bGJ54+ME3X2f13TPR5Y=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=BSS3kEEVPWJMysWc+16R1ooY0Yk9CY8tJv+9JLJJnpr+CVyNkwWyi5lf98ExeVoYp YzY0nOZsQxsGAwSSQFfTZvX/7tkIN5M0Dt4asXClg6L0Y++E/l50ZgA2mFjEZyp1b3 4HOKo5gk1Z9p3meHzsiewQ8ainfWu2Bn72fAvhjU= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, kernel test robot , "Russell King (Oracle)" , Catalin Marinas , Linus Torvalds Subject: [PATCH 4.14 19/31] ARM: fix co-processor register typo Date: Thu, 10 Mar 2022 15:18:32 +0100 Message-Id: <20220310140808.096982909@linuxfoundation.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220310140807.524313448@linuxfoundation.org> References: <20220310140807.524313448@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: Russell King (Oracle) commit 33970b031dc4653cc9dc80f2886976706c4c8ef1 upstream. In the recent Spectre BHB patches, there was a typo that is only exposed in certain configurations: mcr p15,0,XX,c7,r5,4 should have been mcr p15,0,XX,c7,c5,4 Reported-by: kernel test robot Fixes: b9baf5c8c5c3 ("ARM: Spectre-BHB workaround") Signed-off-by: Russell King (Oracle) Acked-by: Catalin Marinas Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman Tested-by: Guenter Roeck Tested-by: Linux Kernel Functional Testing --- arch/arm/include/asm/assembler.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/arch/arm/include/asm/assembler.h +++ b/arch/arm/include/asm/assembler.h @@ -116,7 +116,7 @@ .endm =20 .macro isb, args - mcr p15, 0, r0, c7, r5, 4 + mcr p15, 0, r0, c7, c5, 4 .endm #endif From nobody Tue Jun 23 05:03:32 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id D9C31C4332F for ; Thu, 10 Mar 2022 14:26:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243622AbiCJO06 (ORCPT ); Thu, 10 Mar 2022 09:26:58 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57432 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243453AbiCJOWc (ORCPT ); Thu, 10 Mar 2022 09:22:32 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 309A4C7D5D; Thu, 10 Mar 2022 06:20:51 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id AFAB3B82670; Thu, 10 Mar 2022 14:20:49 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id EF85DC36AE2; Thu, 10 Mar 2022 14:20:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1646922048; bh=rOdRjlfGIZYD+n0lj7b5O9mgjt15QtnR/meCRGGomIc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=R2kvQ9em39uUuTgitlhEvRGpuKDwqmwJmXWjaDa3qdb2X/kDQ+VWRHV/RL4QrbgN0 YXMJoScWpONubm5AVaaGrTNAPqklEGVk9uvY63Jdexlla8IYppMGbX0MYbetzY14aY zNO2uwFO8tXsshxnMtsrG/TdprTcBo1feMba54OA= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Nathan Chancellor , Linus Torvalds Subject: [PATCH 4.14 20/31] ARM: Do not use NOCROSSREFS directive with ld.lld Date: Thu, 10 Mar 2022 15:18:33 +0100 Message-Id: <20220310140808.125761504@linuxfoundation.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220310140807.524313448@linuxfoundation.org> References: <20220310140807.524313448@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: Nathan Chancellor commit 36168e387fa7d0f1fe0cd5cf76c8cea7aee714fa upstream. ld.lld does not support the NOCROSSREFS directive at the moment, which breaks the build after commit b9baf5c8c5c3 ("ARM: Spectre-BHB workaround"): ld.lld: error: ./arch/arm/kernel/vmlinux.lds:34: AT expected, but got NOC= ROSSREFS Support for this directive will eventually be implemented, at which point a version check can be added. To avoid breaking the build in the meantime, just define NOCROSSREFS to nothing when using ld.lld, with a link to the issue for tracking. Cc: stable@vger.kernel.org Fixes: b9baf5c8c5c3 ("ARM: Spectre-BHB workaround") Link: https://github.com/ClangBuiltLinux/linux/issues/1609 Signed-off-by: Nathan Chancellor Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman Tested-by: Guenter Roeck Tested-by: Linux Kernel Functional Testing --- arch/arm/kernel/vmlinux-xip.lds.S | 8 ++++++++ arch/arm/kernel/vmlinux.lds.S | 8 ++++++++ 2 files changed, 16 insertions(+) --- a/arch/arm/kernel/vmlinux-xip.lds.S +++ b/arch/arm/kernel/vmlinux-xip.lds.S @@ -13,6 +13,14 @@ #include #include =20 +/* + * ld.lld does not support NOCROSSREFS: + * https://github.com/ClangBuiltLinux/linux/issues/1609 + */ +#ifdef CONFIG_LD_IS_LLD +#define NOCROSSREFS +#endif + /* Set start/end symbol names to the LMA for the section */ #define ARM_LMA(sym, section) \ sym##_start =3D LOADADDR(section); \ --- a/arch/arm/kernel/vmlinux.lds.S +++ b/arch/arm/kernel/vmlinux.lds.S @@ -15,6 +15,14 @@ #include #include =20 +/* + * ld.lld does not support NOCROSSREFS: + * https://github.com/ClangBuiltLinux/linux/issues/1609 + */ +#ifdef CONFIG_LD_IS_LLD +#define NOCROSSREFS +#endif + /* Set start/end symbol names to the LMA for the section */ #define ARM_LMA(sym, section) \ sym##_start =3D LOADADDR(section); \ From nobody Tue Jun 23 05:03:32 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9F755C433EF for ; Thu, 10 Mar 2022 14:25:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243522AbiCJO0h (ORCPT ); Thu, 10 Mar 2022 09:26:37 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59020 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243464AbiCJOWn (ORCPT ); Thu, 10 Mar 2022 09:22:43 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 034B4150405; Thu, 10 Mar 2022 06:20:53 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 8203961CFF; Thu, 10 Mar 2022 14:20:52 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4796CC36AFA; Thu, 10 Mar 2022 14:20:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1646922051; bh=xj+QdKUrjDDFGwApWZ1l3iJAR6528yj7oSQnmuWft5c=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=AWb06PBKrVLK88WItDC1xqqzyv9KFokfR818sFONlLPjDwoH+n7qqDE4EXkcD0WX0 RtoV0MYWgMg/Rpdh9E9stLTqEnzOrluRMz9HPvyE7AxDiAU1CEATkYjVyybg7xoYka AcQZR+zPug4yRn5i4sQ67A24koLgv/EcopiIEpCw= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, kernel test robot , "Russell King (Oracle)" , Linus Torvalds Subject: [PATCH 4.14 21/31] ARM: fix build warning in proc-v7-bugs.c Date: Thu, 10 Mar 2022 15:18:34 +0100 Message-Id: <20220310140808.155501261@linuxfoundation.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220310140807.524313448@linuxfoundation.org> References: <20220310140807.524313448@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: Russell King (Oracle) commit b1a384d2cbccb1eb3f84765020d25e2c1929706e upstream. The kernel test robot discovered that building without HARDEN_BRANCH_PREDICTOR issues a warning due to a missing argument to pr_info(). Add the missing argument. Reported-by: kernel test robot Fixes: 9dd78194a372 ("ARM: report Spectre v2 status through sysfs") Signed-off-by: Russell King (Oracle) Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman Tested-by: Guenter Roeck Tested-by: Linux Kernel Functional Testing --- arch/arm/mm/proc-v7-bugs.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/arch/arm/mm/proc-v7-bugs.c +++ b/arch/arm/mm/proc-v7-bugs.c @@ -110,7 +110,8 @@ static unsigned int spectre_v2_install_w #else static unsigned int spectre_v2_install_workaround(unsigned int method) { - pr_info("CPU%u: Spectre V2: workarounds disabled by configuration\n"); + pr_info("CPU%u: Spectre V2: workarounds disabled by configuration\n", + smp_processor_id()); =20 return SPECTRE_VULNERABLE; } From nobody Tue Jun 23 05:03:32 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 35697C433EF for ; Thu, 10 Mar 2022 14:25:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243460AbiCJO0o (ORCPT ); Thu, 10 Mar 2022 09:26:44 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58554 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243569AbiCJOXD (ORCPT ); Thu, 10 Mar 2022 09:23:03 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E39AB154719; Thu, 10 Mar 2022 06:20:57 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 77869B8267A; Thu, 10 Mar 2022 14:20:56 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id B0D41C340E8; Thu, 10 Mar 2022 14:20:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1646922055; bh=vzSF9NLTj2CC/EtyDWRBsEmCrp/t8LoHmGjSgMq5smc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ZvEFQsLis5YjMNjKeX1shlXk+0fhDGbiqpiqPfyarkJOkOvJuT9mL8FVySm+M/ROd Xcu6eVLHo6QXUK5dzfzxjvEx/spQb1i0II9xDqsVl6Qxmr8uRz5wS+1IMjvoc+j0E5 erQLvOUHdbk5htCBKelphdxvApXDvxT9LBNcNTdY= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Demi Marie Obenour , Juergen Gross , Jan Beulich Subject: [PATCH 4.14 22/31] xen/xenbus: dont let xenbus_grant_ring() remove grants in error case Date: Thu, 10 Mar 2022 15:18:35 +0100 Message-Id: <20220310140808.186042536@linuxfoundation.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220310140807.524313448@linuxfoundation.org> References: <20220310140807.524313448@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: Juergen Gross Commit 3777ea7bac3113005b7180e6b9dadf16d19a5827 upstream. Letting xenbus_grant_ring() tear down grants in the error case is problematic, as the other side could already have used these grants. Calling gnttab_end_foreign_access_ref() without checking success is resulting in an unclear situation for any caller of xenbus_grant_ring() as in the error case the memory pages of the ring page might be partially mapped. Freeing them would risk unwanted foreign access to them, while not freeing them would leak memory. In order to remove the need to undo any gnttab_grant_foreign_access() calls, use gnttab_alloc_grant_references() to make sure no further error can occur in the loop granting access to the ring pages. It should be noted that this way of handling removes leaking of grant entries in the error case, too. This is CVE-2022-23040 / part of XSA-396. Reported-by: Demi Marie Obenour Signed-off-by: Juergen Gross Reviewed-by: Jan Beulich Signed-off-by: Greg Kroah-Hartman Tested-by: Guenter Roeck Tested-by: Linux Kernel Functional Testing --- drivers/xen/xenbus/xenbus_client.c | 24 +++++++++++------------- 1 file changed, 11 insertions(+), 13 deletions(-) --- a/drivers/xen/xenbus/xenbus_client.c +++ b/drivers/xen/xenbus/xenbus_client.c @@ -368,7 +368,14 @@ int xenbus_grant_ring(struct xenbus_devi unsigned int nr_pages, grant_ref_t *grefs) { int err; - int i, j; + unsigned int i; + grant_ref_t gref_head; + + err =3D gnttab_alloc_grant_references(nr_pages, &gref_head); + if (err) { + xenbus_dev_fatal(dev, err, "granting access to ring page"); + return err; + } =20 for (i =3D 0; i < nr_pages; i++) { unsigned long gfn; @@ -378,23 +385,14 @@ int xenbus_grant_ring(struct xenbus_devi else gfn =3D virt_to_gfn(vaddr); =20 - err =3D gnttab_grant_foreign_access(dev->otherend_id, gfn, 0); - if (err < 0) { - xenbus_dev_fatal(dev, err, - "granting access to ring page"); - goto fail; - } - grefs[i] =3D err; + grefs[i] =3D gnttab_claim_grant_reference(&gref_head); + gnttab_grant_foreign_access_ref(grefs[i], dev->otherend_id, + gfn, 0); =20 vaddr =3D vaddr + XEN_PAGE_SIZE; } =20 return 0; - -fail: - for (j =3D 0; j < i; j++) - gnttab_end_foreign_access_ref(grefs[j], 0); - return err; } EXPORT_SYMBOL_GPL(xenbus_grant_ring); From nobody Tue Jun 23 05:03:32 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 32C89C433FE for ; Thu, 10 Mar 2022 14:26:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243730AbiCJO1D (ORCPT ); Thu, 10 Mar 2022 09:27:03 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58452 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243637AbiCJOXI (ORCPT ); Thu, 10 Mar 2022 09:23:08 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 49F91154735; Thu, 10 Mar 2022 06:21:01 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id A6BB1B82678; Thu, 10 Mar 2022 14:20:59 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id E4C76C36AF7; Thu, 10 Mar 2022 14:20:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1646922058; bh=4sRvDsU0YzxJTpWFP0plNUR7N8iCGw3geGeUgJ8shXI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=boqfHfUIWlKEI+wj+pPx22k07efwQZQiwuCMyQFGjGCPrlJ5/IQVbqATuL5gU3XDG A/EBJSANxkapwLdF42kRolDHggWQrnedKCXLHButKbN//ZfqJBUoyQ26U67+2veT22 99xtW8TQK4aNPzel6Dr1MlGbGGyDO4HREcKqWn4g= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Demi Marie Obenour , Juergen Gross , Jan Beulich Subject: [PATCH 4.14 23/31] xen/grant-table: add gnttab_try_end_foreign_access() Date: Thu, 10 Mar 2022 15:18:36 +0100 Message-Id: <20220310140808.215242873@linuxfoundation.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220310140807.524313448@linuxfoundation.org> References: <20220310140807.524313448@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: Juergen Gross Commit 6b1775f26a2da2b05a6dc8ec2b5d14e9a4701a1a upstream. Add a new grant table function gnttab_try_end_foreign_access(), which will remove and free a grant if it is not in use. Its main use case is to either free a grant if it is no longer in use, or to take some other action if it is still in use. This other action can be an error exit, or (e.g. in the case of blkfront persistent grant feature) some special handling. This is CVE-2022-23036, CVE-2022-23038 / part of XSA-396. Reported-by: Demi Marie Obenour Signed-off-by: Juergen Gross Reviewed-by: Jan Beulich Signed-off-by: Greg Kroah-Hartman Tested-by: Guenter Roeck Tested-by: Linux Kernel Functional Testing --- drivers/xen/grant-table.c | 14 ++++++++++++-- include/xen/grant_table.h | 12 ++++++++++++ 2 files changed, 24 insertions(+), 2 deletions(-) --- a/drivers/xen/grant-table.c +++ b/drivers/xen/grant-table.c @@ -378,11 +378,21 @@ static void gnttab_add_deferred(grant_re what, ref, page ? page_to_pfn(page) : -1); } =20 +int gnttab_try_end_foreign_access(grant_ref_t ref) +{ + int ret =3D _gnttab_end_foreign_access_ref(ref, 0); + + if (ret) + put_free_entry(ref); + + return ret; +} +EXPORT_SYMBOL_GPL(gnttab_try_end_foreign_access); + void gnttab_end_foreign_access(grant_ref_t ref, int readonly, unsigned long page) { - if (gnttab_end_foreign_access_ref(ref, readonly)) { - put_free_entry(ref); + if (gnttab_try_end_foreign_access(ref)) { if (page !=3D 0) put_page(virt_to_page(page)); } else --- a/include/xen/grant_table.h +++ b/include/xen/grant_table.h @@ -97,10 +97,22 @@ int gnttab_end_foreign_access_ref(grant_ * access has been ended, free the given page too. Access will be ended * immediately iff the grant entry is not in use, otherwise it will happen * some time later. page may be 0, in which case no freeing will occur. + * Note that the granted page might still be accessed (read or write) by t= he + * other side after gnttab_end_foreign_access() returns, so even if page w= as + * specified as 0 it is not allowed to just reuse the page for other + * purposes immediately. */ void gnttab_end_foreign_access(grant_ref_t ref, int readonly, unsigned long page); =20 +/* + * End access through the given grant reference, iff the grant entry is + * no longer in use. In case of success ending foreign access, the + * grant reference is deallocated. + * Return 1 if the grant entry was freed, 0 if it is still in use. + */ +int gnttab_try_end_foreign_access(grant_ref_t ref); + int gnttab_grant_foreign_transfer(domid_t domid, unsigned long pfn); =20 unsigned long gnttab_end_foreign_transfer_ref(grant_ref_t ref); From nobody Tue Jun 23 05:03:32 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id A6B58C433F5 for ; Thu, 10 Mar 2022 14:25:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243673AbiCJO0y (ORCPT ); Thu, 10 Mar 2022 09:26:54 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58500 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243686AbiCJOXK (ORCPT ); Thu, 10 Mar 2022 09:23:10 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4B88C155C21; Thu, 10 Mar 2022 06:21:05 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id EEDA861CEF; Thu, 10 Mar 2022 14:21:01 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 003A4C340E8; Thu, 10 Mar 2022 14:21:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1646922061; bh=6kpmxXJFJ49SxE+RUHrRRV+RS/FfFJH6KtFJsVXrJYg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=E5ETBFMkEd6R4NxQZ4TCwvDjeksBsVq/FhiTldkRqIhTVGgG1wEGBO0w7jG4+WERQ KbLtgg2Nf4AITgsPo3o15rUy1WWcr/+xHX7ZEbelHu3KGwMGBQyWy5on/Sz5H/zcRp ElYi5ZlWEvTUq82sDVfbz4t4qVoTTvI++NTzMLTA= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Demi Marie Obenour , Juergen Gross , =?UTF-8?q?Roger=20Pau=20Monn=C3=A9?= Subject: [PATCH 4.14 24/31] xen/blkfront: dont use gnttab_query_foreign_access() for mapped status Date: Thu, 10 Mar 2022 15:18:37 +0100 Message-Id: <20220310140808.245040489@linuxfoundation.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220310140807.524313448@linuxfoundation.org> References: <20220310140807.524313448@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Juergen Gross Commit abf1fd5919d6238ee3bc5eb4a9b6c3947caa6638 upstream. It isn't enough to check whether a grant is still being in use by calling gnttab_query_foreign_access(), as a mapping could be realized by the other side just after having called that function. In case the call was done in preparation of revoking a grant it is better to do so via gnttab_end_foreign_access_ref() and check the success of that operation instead. For the ring allocation use alloc_pages_exact() in order to avoid high order pages in case of a multi-page ring. If a grant wasn't unmapped by the backend without persistent grants being used, set the device state to "error". This is CVE-2022-23036 / part of XSA-396. Reported-by: Demi Marie Obenour Signed-off-by: Juergen Gross Reviewed-by: Roger Pau Monn=C3=A9 Signed-off-by: Greg Kroah-Hartman Tested-by: Guenter Roeck Tested-by: Linux Kernel Functional Testing --- drivers/block/xen-blkfront.c | 67 +++++++++++++++++++++++++-------------= ----- 1 file changed, 39 insertions(+), 28 deletions(-) --- a/drivers/block/xen-blkfront.c +++ b/drivers/block/xen-blkfront.c @@ -1278,17 +1278,16 @@ static void blkif_free_ring(struct blkfr list_for_each_entry_safe(persistent_gnt, n, &rinfo->grants, node) { list_del(&persistent_gnt->node); - if (persistent_gnt->gref !=3D GRANT_INVALID_REF) { - gnttab_end_foreign_access(persistent_gnt->gref, - 0, 0UL); - rinfo->persistent_gnts_c--; - } + if (persistent_gnt->gref =3D=3D GRANT_INVALID_REF || + !gnttab_try_end_foreign_access(persistent_gnt->gref)) + continue; + + rinfo->persistent_gnts_c--; if (info->feature_persistent) __free_page(persistent_gnt->page); kfree(persistent_gnt); } } - BUG_ON(rinfo->persistent_gnts_c !=3D 0); =20 for (i =3D 0; i < BLK_RING_SIZE(info); i++) { /* @@ -1345,7 +1344,8 @@ free_shadow: rinfo->ring_ref[i] =3D GRANT_INVALID_REF; } } - free_pages((unsigned long)rinfo->ring.sring, get_order(info->nr_ring_page= s * XEN_PAGE_SIZE)); + free_pages_exact(rinfo->ring.sring, + info->nr_ring_pages * XEN_PAGE_SIZE); rinfo->ring.sring =3D NULL; =20 if (rinfo->irq) @@ -1429,9 +1429,15 @@ static int blkif_get_final_status(enum b return BLKIF_RSP_OKAY; } =20 -static bool blkif_completion(unsigned long *id, - struct blkfront_ring_info *rinfo, - struct blkif_response *bret) +/* + * Return values: + * 1 response processed. + * 0 missing further responses. + * -1 error while processing. + */ +static int blkif_completion(unsigned long *id, + struct blkfront_ring_info *rinfo, + struct blkif_response *bret) { int i =3D 0; struct scatterlist *sg; @@ -1505,42 +1511,43 @@ static bool blkif_completion(unsigned lo } /* Add the persistent grant into the list of free grants */ for (i =3D 0; i < num_grant; i++) { - if (gnttab_query_foreign_access(s->grants_used[i]->gref)) { + if (!gnttab_try_end_foreign_access(s->grants_used[i]->gref)) { /* * If the grant is still mapped by the backend (the * backend has chosen to make this grant persistent) * we add it at the head of the list, so it will be * reused first. */ - if (!info->feature_persistent) - pr_alert_ratelimited("backed has not unmapped grant: %u\n", - s->grants_used[i]->gref); + if (!info->feature_persistent) { + pr_alert("backed has not unmapped grant: %u\n", + s->grants_used[i]->gref); + return -1; + } list_add(&s->grants_used[i]->node, &rinfo->grants); rinfo->persistent_gnts_c++; } else { /* - * If the grant is not mapped by the backend we end the - * foreign access and add it to the tail of the list, - * so it will not be picked again unless we run out of - * persistent grants. + * If the grant is not mapped by the backend we add it + * to the tail of the list, so it will not be picked + * again unless we run out of persistent grants. */ - gnttab_end_foreign_access(s->grants_used[i]->gref, 0, 0UL); s->grants_used[i]->gref =3D GRANT_INVALID_REF; list_add_tail(&s->grants_used[i]->node, &rinfo->grants); } } if (s->req.operation =3D=3D BLKIF_OP_INDIRECT) { for (i =3D 0; i < INDIRECT_GREFS(num_grant); i++) { - if (gnttab_query_foreign_access(s->indirect_grants[i]->gref)) { - if (!info->feature_persistent) - pr_alert_ratelimited("backed has not unmapped grant: %u\n", - s->indirect_grants[i]->gref); + if (!gnttab_try_end_foreign_access(s->indirect_grants[i]->gref)) { + if (!info->feature_persistent) { + pr_alert("backed has not unmapped grant: %u\n", + s->indirect_grants[i]->gref); + return -1; + } list_add(&s->indirect_grants[i]->node, &rinfo->grants); rinfo->persistent_gnts_c++; } else { struct page *indirect_page; =20 - gnttab_end_foreign_access(s->indirect_grants[i]->gref, 0, 0UL); /* * Add the used indirect page back to the list of * available pages for indirect grefs. @@ -1621,12 +1628,17 @@ static irqreturn_t blkif_interrupt(int i } =20 if (bret.operation !=3D BLKIF_OP_DISCARD) { + int ret; + /* * We may need to wait for an extra response if the * I/O request is split in 2 */ - if (!blkif_completion(&id, rinfo, &bret)) + ret =3D blkif_completion(&id, rinfo, &bret); + if (!ret) continue; + if (unlikely(ret < 0)) + goto err; } =20 if (add_id_to_freelist(rinfo, id)) { @@ -1732,8 +1744,7 @@ static int setup_blkring(struct xenbus_d for (i =3D 0; i < info->nr_ring_pages; i++) rinfo->ring_ref[i] =3D GRANT_INVALID_REF; =20 - sring =3D (struct blkif_sring *)__get_free_pages(GFP_NOIO | __GFP_HIGH, - get_order(ring_size)); + sring =3D alloc_pages_exact(ring_size, GFP_NOIO); if (!sring) { xenbus_dev_fatal(dev, -ENOMEM, "allocating shared ring"); return -ENOMEM; @@ -1743,7 +1754,7 @@ static int setup_blkring(struct xenbus_d =20 err =3D xenbus_grant_ring(dev, rinfo->ring.sring, info->nr_ring_pages, gr= ef); if (err < 0) { - free_pages((unsigned long)sring, get_order(ring_size)); + free_pages_exact(sring, ring_size); rinfo->ring.sring =3D NULL; goto fail; } From nobody Tue Jun 23 05:03:32 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 117BBC433EF for ; Thu, 10 Mar 2022 14:26:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243761AbiCJO1H (ORCPT ); Thu, 10 Mar 2022 09:27:07 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57426 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243726AbiCJOXM (ORCPT ); Thu, 10 Mar 2022 09:23:12 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8C8FB15696D; Thu, 10 Mar 2022 06:21:11 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id D42F861CEE; Thu, 10 Mar 2022 14:21:04 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id E2745C340E8; Thu, 10 Mar 2022 14:21:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1646922064; bh=mFLGwyxL60zb3gvRg16qJDVO+v5CSOIO6jNpfVxbb6s=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=PJAKjfVkjsZfZZiVuAOg3K3VrBA1x2fb3tN1yyeKlBuMI8sApwgYFyQbvDpVE33h1 CNf+iI/LnpD5AHQHwW3oYT1CFboOf3BpVZBmthFzv586zcb/mi7zdHEYzFDeYLa6c8 Op/9DolmISjWO0AckpvsytDb9PXN+Jg3Vb6cQYRs= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Demi Marie Obenour , Juergen Gross , Jan Beulich Subject: [PATCH 4.14 25/31] xen/netfront: dont use gnttab_query_foreign_access() for mapped status Date: Thu, 10 Mar 2022 15:18:38 +0100 Message-Id: <20220310140808.274494842@linuxfoundation.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220310140807.524313448@linuxfoundation.org> References: <20220310140807.524313448@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: Juergen Gross Commit 31185df7e2b1d2fa1de4900247a12d7b9c7087eb upstream. It isn't enough to check whether a grant is still being in use by calling gnttab_query_foreign_access(), as a mapping could be realized by the other side just after having called that function. In case the call was done in preparation of revoking a grant it is better to do so via gnttab_end_foreign_access_ref() and check the success of that operation instead. This is CVE-2022-23037 / part of XSA-396. Reported-by: Demi Marie Obenour Signed-off-by: Juergen Gross Reviewed-by: Jan Beulich Signed-off-by: Greg Kroah-Hartman Tested-by: Guenter Roeck Tested-by: Linux Kernel Functional Testing --- drivers/net/xen-netfront.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) --- a/drivers/net/xen-netfront.c +++ b/drivers/net/xen-netfront.c @@ -414,14 +414,12 @@ static bool xennet_tx_buf_gc(struct netf queue->tx_link[id] =3D TX_LINK_NONE; skb =3D queue->tx_skbs[id]; queue->tx_skbs[id] =3D NULL; - if (unlikely(gnttab_query_foreign_access( - queue->grant_tx_ref[id]) !=3D 0)) { + if (unlikely(!gnttab_end_foreign_access_ref( + queue->grant_tx_ref[id], GNTMAP_readonly))) { dev_alert(dev, "Grant still in use by backend domain\n"); goto err; } - gnttab_end_foreign_access_ref( - queue->grant_tx_ref[id], GNTMAP_readonly); gnttab_release_grant_reference( &queue->gref_tx_head, queue->grant_tx_ref[id]); queue->grant_tx_ref[id] =3D GRANT_INVALID_REF; From nobody Tue Jun 23 05:03:32 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id DC797C433EF for ; Thu, 10 Mar 2022 14:26:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243782AbiCJO1T (ORCPT ); Thu, 10 Mar 2022 09:27:19 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58460 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243446AbiCJOXT (ORCPT ); Thu, 10 Mar 2022 09:23:19 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B8C0BC0848; Thu, 10 Mar 2022 06:21:19 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id F166861B1F; Thu, 10 Mar 2022 14:21:08 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id D1F9EC340F3; Thu, 10 Mar 2022 14:21:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1646922068; bh=a//jtcByFiHXOCJ+/M4jiKQWdvoAGv/83F2/7HhgSnI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=NyYIpXODMGCgB8IrRaQr0BmaGqjxx6PXsVLObvVw7npUvhLAzOLVGdXb9PRtFvple zkIgRJ4956kfGlpKeWPfE7UBlUZh17NCDhk7T0FGS37wLPHQbOHJhezUBEEEvQJghl yfwE7c5Up2PaX9SrFqv7+x9PlNzi3QNb+H1ZdW5s= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Demi Marie Obenour , Juergen Gross , Jan Beulich Subject: [PATCH 4.14 26/31] xen/scsifront: dont use gnttab_query_foreign_access() for mapped status Date: Thu, 10 Mar 2022 15:18:39 +0100 Message-Id: <20220310140808.303290685@linuxfoundation.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220310140807.524313448@linuxfoundation.org> References: <20220310140807.524313448@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: Juergen Gross Commit 33172ab50a53578a95691310f49567c9266968b0 upstream. It isn't enough to check whether a grant is still being in use by calling gnttab_query_foreign_access(), as a mapping could be realized by the other side just after having called that function. In case the call was done in preparation of revoking a grant it is better to do so via gnttab_try_end_foreign_access() and check the success of that operation instead. This is CVE-2022-23038 / part of XSA-396. Reported-by: Demi Marie Obenour Signed-off-by: Juergen Gross Reviewed-by: Jan Beulich Signed-off-by: Greg Kroah-Hartman Tested-by: Guenter Roeck Tested-by: Linux Kernel Functional Testing --- drivers/scsi/xen-scsifront.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) --- a/drivers/scsi/xen-scsifront.c +++ b/drivers/scsi/xen-scsifront.c @@ -233,12 +233,11 @@ static void scsifront_gnttab_done(struct return; =20 for (i =3D 0; i < shadow->nr_grants; i++) { - if (unlikely(gnttab_query_foreign_access(shadow->gref[i]))) { + if (unlikely(!gnttab_try_end_foreign_access(shadow->gref[i]))) { shost_printk(KERN_ALERT, info->host, KBUILD_MODNAME "grant still in use by backend\n"); BUG(); } - gnttab_end_foreign_access(shadow->gref[i], 0, 0UL); } =20 kfree(shadow->sg); From nobody Tue Jun 23 05:03:32 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 09FABC433EF for ; Thu, 10 Mar 2022 14:26:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243769AbiCJO1M (ORCPT ); Thu, 10 Mar 2022 09:27:12 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57432 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243746AbiCJOXN (ORCPT ); Thu, 10 Mar 2022 09:23:13 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2D1D6158794; Thu, 10 Mar 2022 06:21:14 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 4C674B825A7; Thu, 10 Mar 2022 14:21:12 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9EAE7C340F5; Thu, 10 Mar 2022 14:21:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1646922071; bh=T/mHRVpyB/klvNBKNmoZm1usKzPz4/NT8r60/gXuNsc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=qh1+6HPJAwpLhZerrbYE5m4qhqcGDTakEcjsqBkHe0q82f0z1fq6BLoKBZhoFEjS8 yLjkqWNQX++iiTK6BGcsJurTEWUDHKexZufLWE8LQ8K+cs9d6bzs3hkTpY1asyo7yR aVYj+A5V41h76buxqJEeIgwviYXsNjos5rNceGtk= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Demi Marie Obenour , Juergen Gross , Jan Beulich Subject: [PATCH 4.14 27/31] xen/gntalloc: dont use gnttab_query_foreign_access() Date: Thu, 10 Mar 2022 15:18:40 +0100 Message-Id: <20220310140808.332010211@linuxfoundation.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220310140807.524313448@linuxfoundation.org> References: <20220310140807.524313448@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: Juergen Gross Commit d3b6372c5881cb54925212abb62c521df8ba4809 upstream. Using gnttab_query_foreign_access() is unsafe, as it is racy by design. The use case in the gntalloc driver is not needed at all. While at it replace the call of gnttab_end_foreign_access_ref() with a call of gnttab_end_foreign_access(), which is what is really wanted there. In case the grant wasn't used due to an allocation failure, just free the grant via gnttab_free_grant_reference(). This is CVE-2022-23039 / part of XSA-396. Reported-by: Demi Marie Obenour Signed-off-by: Juergen Gross Reviewed-by: Jan Beulich Signed-off-by: Greg Kroah-Hartman Tested-by: Guenter Roeck Tested-by: Linux Kernel Functional Testing --- drivers/xen/gntalloc.c | 25 +++++++------------------ 1 file changed, 7 insertions(+), 18 deletions(-) --- a/drivers/xen/gntalloc.c +++ b/drivers/xen/gntalloc.c @@ -169,20 +169,14 @@ undo: __del_gref(gref); } =20 - /* It's possible for the target domain to map the just-allocated grant - * references by blindly guessing their IDs; if this is done, then - * __del_gref will leave them in the queue_gref list. They need to be - * added to the global list so that we can free them when they are no - * longer referenced. - */ - if (unlikely(!list_empty(&queue_gref))) - list_splice_tail(&queue_gref, &gref_list); mutex_unlock(&gref_mutex); return rc; } =20 static void __del_gref(struct gntalloc_gref *gref) { + unsigned long addr; + if (gref->notify.flags & UNMAP_NOTIFY_CLEAR_BYTE) { uint8_t *tmp =3D kmap(gref->page); tmp[gref->notify.pgoff] =3D 0; @@ -196,21 +190,16 @@ static void __del_gref(struct gntalloc_g gref->notify.flags =3D 0; =20 if (gref->gref_id) { - if (gnttab_query_foreign_access(gref->gref_id)) - return; - - if (!gnttab_end_foreign_access_ref(gref->gref_id, 0)) - return; - - gnttab_free_grant_reference(gref->gref_id); + if (gref->page) { + addr =3D (unsigned long)page_to_virt(gref->page); + gnttab_end_foreign_access(gref->gref_id, 0, addr); + } else + gnttab_free_grant_reference(gref->gref_id); } =20 gref_size--; list_del(&gref->next_gref); =20 - if (gref->page) - __free_page(gref->page); - kfree(gref); } From nobody Tue Jun 23 05:03:32 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 432DDC433EF for ; Thu, 10 Mar 2022 14:26:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243789AbiCJO1Z (ORCPT ); Thu, 10 Mar 2022 09:27:25 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57432 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243558AbiCJOYR (ORCPT ); Thu, 10 Mar 2022 09:24:17 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0241F15AF17; Thu, 10 Mar 2022 06:21:27 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 31893B8254A; Thu, 10 Mar 2022 14:21:15 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8996EC340E8; Thu, 10 Mar 2022 14:21:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1646922073; bh=homSW79ERgDC4wOvioAVB6uYm3zjRaRoNQR6qFezAr0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=XCvN8tt0HgQ6QLqTMLPC0/TaWWpdNWKPvj/1aQlfTOzjaAAnP2+5B8U1A2/pWAUz7 MvCR6wN8NG5Nz0YppkCG9TVQad83IjxjDCir+dO6F4OH/3pG0UYoFmjYtxBIXk4prt eeBVke3nK4g3AYuHKFHr29h3uaMZcEWmSkUqgHYU= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Juergen Gross , Jan Beulich Subject: [PATCH 4.14 28/31] xen: remove gnttab_query_foreign_access() Date: Thu, 10 Mar 2022 15:18:41 +0100 Message-Id: <20220310140808.360509359@linuxfoundation.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220310140807.524313448@linuxfoundation.org> References: <20220310140807.524313448@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: Juergen Gross Commit 1dbd11ca75fe664d3e54607547771d021f531f59 upstream. Remove gnttab_query_foreign_access(), as it is unused and unsafe to use. All previous use cases assumed a grant would not be in use after gnttab_query_foreign_access() returned 0. This information is useless in best case, as it only refers to a situation in the past, which could have changed already. Signed-off-by: Juergen Gross Reviewed-by: Jan Beulich Signed-off-by: Greg Kroah-Hartman Tested-by: Guenter Roeck Tested-by: Linux Kernel Functional Testing --- drivers/xen/grant-table.c | 19 ------------------- include/xen/grant_table.h | 2 -- 2 files changed, 21 deletions(-) --- a/drivers/xen/grant-table.c +++ b/drivers/xen/grant-table.c @@ -114,13 +114,6 @@ struct gnttab_ops { * return the frame. */ unsigned long (*end_foreign_transfer_ref)(grant_ref_t ref); - /* - * Query the status of a grant entry. Ref parameter is reference of - * queried grant entry, return value is the status of queried entry. - * Detailed status(writing/reading) can be gotten from the return value - * by bit operations. - */ - int (*query_foreign_access)(grant_ref_t ref); }; =20 struct unmap_refs_callback_data { @@ -255,17 +248,6 @@ int gnttab_grant_foreign_access(domid_t } EXPORT_SYMBOL_GPL(gnttab_grant_foreign_access); =20 -static int gnttab_query_foreign_access_v1(grant_ref_t ref) -{ - return gnttab_shared.v1[ref].flags & (GTF_reading|GTF_writing); -} - -int gnttab_query_foreign_access(grant_ref_t ref) -{ - return gnttab_interface->query_foreign_access(ref); -} -EXPORT_SYMBOL_GPL(gnttab_query_foreign_access); - static int gnttab_end_foreign_access_ref_v1(grant_ref_t ref, int readonly) { u16 flags, nflags; @@ -1029,7 +1011,6 @@ static const struct gnttab_ops gnttab_v1 .update_entry =3D gnttab_update_entry_v1, .end_foreign_access_ref =3D gnttab_end_foreign_access_ref_v1, .end_foreign_transfer_ref =3D gnttab_end_foreign_transfer_ref_v1, - .query_foreign_access =3D gnttab_query_foreign_access_v1, }; =20 static void gnttab_request_version(void) --- a/include/xen/grant_table.h +++ b/include/xen/grant_table.h @@ -118,8 +118,6 @@ int gnttab_grant_foreign_transfer(domid_ unsigned long gnttab_end_foreign_transfer_ref(grant_ref_t ref); unsigned long gnttab_end_foreign_transfer(grant_ref_t ref); =20 -int gnttab_query_foreign_access(grant_ref_t ref); - /* * operations on reserved batches of grant references */ From nobody Tue Jun 23 05:03:32 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8F424C4332F for ; Thu, 10 Mar 2022 14:26:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243686AbiCJO12 (ORCPT ); Thu, 10 Mar 2022 09:27:28 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58470 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243672AbiCJOYt (ORCPT ); Thu, 10 Mar 2022 09:24:49 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 12F1515C188; Thu, 10 Mar 2022 06:21:31 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id F0593B82676; Thu, 10 Mar 2022 14:21:17 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 43856C340EB; Thu, 10 Mar 2022 14:21:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1646922076; bh=Rf8d3UZKqR31JRCPZ7eaY38GzuetOV+dpywHxUuB33c=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=jg2cw7RRVcC+aiSn+SqHZmAdmWbcAgoyEdxB0nNwzHJW4SqNqVsSfeQAn2Vl+fa5I IVoF2Lmrcc5KnH6kzolq9NdvhUyqbHSdn/+553cE0FYG3+1Mtlemfo4Wqchukn+j+H 3htezVYUtfNkx0hKPnSzDihW+sr0ZsgQ5BIlVbHw= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Simon Gaiser , Juergen Gross , Jan Beulich Subject: [PATCH 4.14 29/31] xen/9p: use alloc/free_pages_exact() Date: Thu, 10 Mar 2022 15:18:42 +0100 Message-Id: <20220310140808.390344695@linuxfoundation.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220310140807.524313448@linuxfoundation.org> References: <20220310140807.524313448@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: Juergen Gross Commit 5cadd4bb1d7fc9ab201ac14620d1a478357e4ebd upstream. Instead of __get_free_pages() and free_pages() use alloc_pages_exact() and free_pages_exact(). This is in preparation of a change of gnttab_end_foreign_access() which will prohibit use of high-order pages. By using the local variable "order" instead of ring->intf->ring_order in the error path of xen_9pfs_front_alloc_dataring() another bug is fixed, as the error path can be entered before ring->intf->ring_order is being set. By using alloc_pages_exact() the size in bytes is specified for the allocation, which fixes another bug for the case of order < (PAGE_SHIFT - XEN_PAGE_SHIFT). This is part of CVE-2022-23041 / XSA-396. Reported-by: Simon Gaiser Signed-off-by: Juergen Gross Reviewed-by: Jan Beulich Signed-off-by: Greg Kroah-Hartman Tested-by: Guenter Roeck Tested-by: Linux Kernel Functional Testing --- net/9p/trans_xen.c | 14 ++++++-------- 1 file changed, 6 insertions(+), 8 deletions(-) --- a/net/9p/trans_xen.c +++ b/net/9p/trans_xen.c @@ -301,9 +301,9 @@ static void xen_9pfs_front_free(struct x ref =3D priv->rings[i].intf->ref[j]; gnttab_end_foreign_access(ref, 0, 0); } - free_pages((unsigned long)priv->rings[i].data.in, - XEN_9PFS_RING_ORDER - - (PAGE_SHIFT - XEN_PAGE_SHIFT)); + free_pages_exact(priv->rings[i].data.in, + 1UL << (XEN_9PFS_RING_ORDER + + XEN_PAGE_SHIFT)); } gnttab_end_foreign_access(priv->rings[i].ref, 0, 0); free_page((unsigned long)priv->rings[i].intf); @@ -341,8 +341,8 @@ static int xen_9pfs_front_alloc_dataring if (ret < 0) goto out; ring->ref =3D ret; - bytes =3D (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, - XEN_9PFS_RING_ORDER - (PAGE_SHIFT - XEN_PAGE_SHIFT)); + bytes =3D alloc_pages_exact(1UL << (XEN_9PFS_RING_ORDER + XEN_PAGE_SHIFT), + GFP_KERNEL | __GFP_ZERO); if (!bytes) { ret =3D -ENOMEM; goto out; @@ -373,9 +373,7 @@ out: if (bytes) { for (i--; i >=3D 0; i--) gnttab_end_foreign_access(ring->intf->ref[i], 0, 0); - free_pages((unsigned long)bytes, - XEN_9PFS_RING_ORDER - - (PAGE_SHIFT - XEN_PAGE_SHIFT)); + free_pages_exact(bytes, 1UL << (XEN_9PFS_RING_ORDER + XEN_PAGE_SHIFT)); } gnttab_end_foreign_access(ring->ref, 0, 0); free_page((unsigned long)ring->intf); From nobody Tue Jun 23 05:03:32 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id F33C8C433EF for ; Thu, 10 Mar 2022 14:26:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243681AbiCJO1m (ORCPT ); Thu, 10 Mar 2022 09:27:42 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58610 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243712AbiCJOZC (ORCPT ); Thu, 10 Mar 2022 09:25:02 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 537B015F373; Thu, 10 Mar 2022 06:21:38 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 931D6B82678; Thu, 10 Mar 2022 14:21:23 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id D72F1C340EB; Thu, 10 Mar 2022 14:21:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1646922082; bh=WMBsDGoFwKsBC3UgmdydLX9aTvQjG9Z/G7T0quQ9LAM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Zb7Ot0ZLD3/IpdTGiL2I+T+bKCl54QkryaeFAiyaihphbFHL8BsHpmCe+amaPMRlx RBMCQSmEJFZKiuR9xeIxdH3KtgsHnPU4KEXBF+lpAx72u3pwGSbQ5DleqgtQxEv4pG vz8LAFF/ZckAtWtQgmKVKm33XycdbABeWz765yAo= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Simon Gaiser , Juergen Gross , Jan Beulich Subject: [PATCH 4.14 30/31] xen/gnttab: fix gnttab_end_foreign_access() without page specified Date: Thu, 10 Mar 2022 15:18:43 +0100 Message-Id: <20220310140808.419605112@linuxfoundation.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220310140807.524313448@linuxfoundation.org> References: <20220310140807.524313448@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: Juergen Gross Commit 42baefac638f06314298087394b982ead9ec444b upstream. gnttab_end_foreign_access() is used to free a grant reference and optionally to free the associated page. In case the grant is still in use by the other side processing is being deferred. This leads to a problem in case no page to be freed is specified by the caller: the caller doesn't know that the page is still mapped by the other side and thus should not be used for other purposes. The correct way to handle this situation is to take an additional reference to the granted page in case handling is being deferred and to drop that reference when the grant reference could be freed finally. This requires that there are no users of gnttab_end_foreign_access() left directly repurposing the granted page after the call, as this might result in clobbered data or information leaks via the not yet freed grant reference. This is part of CVE-2022-23041 / XSA-396. Reported-by: Simon Gaiser Signed-off-by: Juergen Gross Reviewed-by: Jan Beulich Signed-off-by: Greg Kroah-Hartman Tested-by: Guenter Roeck Tested-by: Linux Kernel Functional Testing --- drivers/xen/grant-table.c | 30 +++++++++++++++++++++++------- include/xen/grant_table.h | 7 ++++++- 2 files changed, 29 insertions(+), 8 deletions(-) --- a/drivers/xen/grant-table.c +++ b/drivers/xen/grant-table.c @@ -114,6 +114,10 @@ struct gnttab_ops { * return the frame. */ unsigned long (*end_foreign_transfer_ref)(grant_ref_t ref); + /* + * Read the frame number related to a given grant reference. + */ + unsigned long (*read_frame)(grant_ref_t ref); }; =20 struct unmap_refs_callback_data { @@ -278,6 +282,11 @@ int gnttab_end_foreign_access_ref(grant_ } EXPORT_SYMBOL_GPL(gnttab_end_foreign_access_ref); =20 +static unsigned long gnttab_read_frame_v1(grant_ref_t ref) +{ + return gnttab_shared.v1[ref].frame; +} + struct deferred_entry { struct list_head list; grant_ref_t ref; @@ -307,12 +316,9 @@ static void gnttab_handle_deferred(unsig spin_unlock_irqrestore(&gnttab_list_lock, flags); if (_gnttab_end_foreign_access_ref(entry->ref, entry->ro)) { put_free_entry(entry->ref); - if (entry->page) { - pr_debug("freeing g.e. %#x (pfn %#lx)\n", - entry->ref, page_to_pfn(entry->page)); - put_page(entry->page); - } else - pr_info("freeing g.e. %#x\n", entry->ref); + pr_debug("freeing g.e. %#x (pfn %#lx)\n", + entry->ref, page_to_pfn(entry->page)); + put_page(entry->page); kfree(entry); entry =3D NULL; } else { @@ -337,9 +343,18 @@ static void gnttab_handle_deferred(unsig static void gnttab_add_deferred(grant_ref_t ref, bool readonly, struct page *page) { - struct deferred_entry *entry =3D kmalloc(sizeof(*entry), GFP_ATOMIC); + struct deferred_entry *entry; + gfp_t gfp =3D (in_atomic() || irqs_disabled()) ? GFP_ATOMIC : GFP_KERNEL; const char *what =3D KERN_WARNING "leaking"; =20 + entry =3D kmalloc(sizeof(*entry), gfp); + if (!page) { + unsigned long gfn =3D gnttab_interface->read_frame(ref); + + page =3D pfn_to_page(gfn_to_pfn(gfn)); + get_page(page); + } + if (entry) { unsigned long flags; =20 @@ -1011,6 +1026,7 @@ static const struct gnttab_ops gnttab_v1 .update_entry =3D gnttab_update_entry_v1, .end_foreign_access_ref =3D gnttab_end_foreign_access_ref_v1, .end_foreign_transfer_ref =3D gnttab_end_foreign_transfer_ref_v1, + .read_frame =3D gnttab_read_frame_v1, }; =20 static void gnttab_request_version(void) --- a/include/xen/grant_table.h +++ b/include/xen/grant_table.h @@ -100,7 +100,12 @@ int gnttab_end_foreign_access_ref(grant_ * Note that the granted page might still be accessed (read or write) by t= he * other side after gnttab_end_foreign_access() returns, so even if page w= as * specified as 0 it is not allowed to just reuse the page for other - * purposes immediately. + * purposes immediately. gnttab_end_foreign_access() will take an addition= al + * reference to the granted page in this case, which is dropped only after + * the grant is no longer in use. + * This requires that multi page allocations for areas subject to + * gnttab_end_foreign_access() are done via alloc_pages_exact() (and freei= ng + * via free_pages_exact()) in order to avoid high order pages. */ void gnttab_end_foreign_access(grant_ref_t ref, int readonly, unsigned long page); From nobody Tue Jun 23 05:03:32 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4B0B0C433EF for ; Thu, 10 Mar 2022 14:26:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243633AbiCJO1d (ORCPT ); Thu, 10 Mar 2022 09:27:33 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59034 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243614AbiCJOY1 (ORCPT ); Thu, 10 Mar 2022 09:24:27 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C66B015B987; Thu, 10 Mar 2022 06:21:28 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 9A96AB825F3; Thu, 10 Mar 2022 14:21:26 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id EA4B2C340EB; Thu, 10 Mar 2022 14:21:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1646922085; bh=1FnLQ0yxm0hkWZ8SMoKBS8VcDsHIwTu4gSbaHuCNTJI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Q/8VpjkgOH+eGOhdALlAInI5M6e6BFLK5so/2egbXX3IpJ35ZbsJQTgt+d83xwpG/ HJphT/DlHujIzo86EXlZinrWjbaDBcU3S4UrLLeisWIi7mnynmeWWaJgKLMh2mnLUB L56XD2sEAUMs5es42lVG35bW3KI/rundAQF4h+Tw= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Demi Marie Obenour , Juergen Gross , Jan Beulich Subject: [PATCH 4.14 31/31] xen/netfront: react properly to failing gnttab_end_foreign_access_ref() Date: Thu, 10 Mar 2022 15:18:44 +0100 Message-Id: <20220310140808.447773285@linuxfoundation.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220310140807.524313448@linuxfoundation.org> References: <20220310140807.524313448@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: Juergen Gross Commit 66e3531b33ee51dad17c463b4d9c9f52e341503d upstream. When calling gnttab_end_foreign_access_ref() the returned value must be tested and the reaction to that value should be appropriate. In case of failure in xennet_get_responses() the reaction should not be to crash the system, but to disable the network device. The calls in setup_netfront() can be replaced by calls of gnttab_end_foreign_access(). While at it avoid double free of ring pages and grant references via xennet_disconnect_backend() in this case. This is CVE-2022-23042 / part of XSA-396. Reported-by: Demi Marie Obenour Signed-off-by: Juergen Gross Reviewed-by: Jan Beulich Signed-off-by: Greg Kroah-Hartman Tested-by: Guenter Roeck Tested-by: Linux Kernel Functional Testing --- drivers/net/xen-netfront.c | 48 +++++++++++++++++++++++++++++-----------= ----- 1 file changed, 31 insertions(+), 17 deletions(-) --- a/drivers/net/xen-netfront.c +++ b/drivers/net/xen-netfront.c @@ -839,7 +839,6 @@ static int xennet_get_responses(struct n int max =3D XEN_NETIF_NR_SLOTS_MIN + (rx->status <=3D RX_COPY_THRESHOLD); int slots =3D 1; int err =3D 0; - unsigned long ret; =20 if (rx->flags & XEN_NETRXF_extra_info) { err =3D xennet_get_extras(queue, extras, rp); @@ -870,8 +869,13 @@ static int xennet_get_responses(struct n goto next; } =20 - ret =3D gnttab_end_foreign_access_ref(ref, 0); - BUG_ON(!ret); + if (!gnttab_end_foreign_access_ref(ref, 0)) { + dev_alert(dev, + "Grant still in use by backend domain\n"); + queue->info->broken =3D true; + dev_alert(dev, "Disabled for further use\n"); + return -EINVAL; + } =20 gnttab_release_grant_reference(&queue->gref_rx_head, ref); =20 @@ -1075,6 +1079,10 @@ static int xennet_poll(struct napi_struc err =3D xennet_get_responses(queue, &rinfo, rp, &tmpq); =20 if (unlikely(err)) { + if (queue->info->broken) { + spin_unlock(&queue->rx_lock); + return 0; + } err: while ((skb =3D __skb_dequeue(&tmpq))) __skb_queue_tail(&errq, skb); @@ -1652,7 +1660,7 @@ static int setup_netfront(struct xenbus_ struct netfront_queue *queue, unsigned int feature_split_evtchn) { struct xen_netif_tx_sring *txs; - struct xen_netif_rx_sring *rxs; + struct xen_netif_rx_sring *rxs =3D NULL; grant_ref_t gref; int err; =20 @@ -1672,21 +1680,21 @@ static int setup_netfront(struct xenbus_ =20 err =3D xenbus_grant_ring(dev, txs, 1, &gref); if (err < 0) - goto grant_tx_ring_fail; + goto fail; queue->tx_ring_ref =3D gref; =20 rxs =3D (struct xen_netif_rx_sring *)get_zeroed_page(GFP_NOIO | __GFP_HIG= H); if (!rxs) { err =3D -ENOMEM; xenbus_dev_fatal(dev, err, "allocating rx ring page"); - goto alloc_rx_ring_fail; + goto fail; } SHARED_RING_INIT(rxs); FRONT_RING_INIT(&queue->rx, rxs, XEN_PAGE_SIZE); =20 err =3D xenbus_grant_ring(dev, rxs, 1, &gref); if (err < 0) - goto grant_rx_ring_fail; + goto fail; queue->rx_ring_ref =3D gref; =20 if (feature_split_evtchn) @@ -1699,22 +1707,28 @@ static int setup_netfront(struct xenbus_ err =3D setup_netfront_single(queue); =20 if (err) - goto alloc_evtchn_fail; + goto fail; =20 return 0; =20 /* If we fail to setup netfront, it is safe to just revoke access to * granted pages because backend is not accessing it at this point. */ -alloc_evtchn_fail: - gnttab_end_foreign_access_ref(queue->rx_ring_ref, 0); -grant_rx_ring_fail: - free_page((unsigned long)rxs); -alloc_rx_ring_fail: - gnttab_end_foreign_access_ref(queue->tx_ring_ref, 0); -grant_tx_ring_fail: - free_page((unsigned long)txs); -fail: + fail: + if (queue->rx_ring_ref !=3D GRANT_INVALID_REF) { + gnttab_end_foreign_access(queue->rx_ring_ref, 0, + (unsigned long)rxs); + queue->rx_ring_ref =3D GRANT_INVALID_REF; + } else { + free_page((unsigned long)rxs); + } + if (queue->tx_ring_ref !=3D GRANT_INVALID_REF) { + gnttab_end_foreign_access(queue->tx_ring_ref, 0, + (unsigned long)txs); + queue->tx_ring_ref =3D GRANT_INVALID_REF; + } else { + free_page((unsigned long)txs); + } return err; }