From nobody Sun Feb 8 04:13:04 2026 Received: from thorn.bewilderbeest.net (thorn.bewilderbeest.net [71.19.156.171]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 982C91DFD9; Thu, 8 Feb 2024 01:26:35 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=71.19.156.171 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1707355597; cv=none; b=fCSdHHTF6NyoPPAVnXbCH2M1nn/F3HDIRMclelOx+W1hQhLZ8i3cb2/lHOXtdyz0DoTjYiZp8GFiUmbvbTcaZdt0k/SaRke7qRkZ0PYu/eqMvmyqK/UyJwOP2iDVVvixrv6vbBVSHYFbZvhhLk7x08goPeOylcf/xY5PWP0PPL4= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1707355597; c=relaxed/simple; bh=ug8BB4J+brYFbiC3nrhWpCBaYptY56PfygpljvCrZgg=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=tl9EQyMf4IymLttnFhW7XVTmjZdSzIbc/H/+zNFm79BSOTbJf89M0r9393UsAd1I2kz5eL6InIQL/o1yWDLvGuBxJI8ZT4dQkzvYK2/Gj4OFgqHkJ4ygOAz4dlM4KR2ijpDw9YlkM1LMGGcKpPv/MpO90dun8NI8Z3X+nE+xFBY= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=bewilderbeest.net; spf=pass smtp.mailfrom=bewilderbeest.net; dkim=pass (1024-bit key) header.d=bewilderbeest.net header.i=@bewilderbeest.net header.b=ONjRy3aH; arc=none smtp.client-ip=71.19.156.171 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=bewilderbeest.net Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=bewilderbeest.net Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=bewilderbeest.net header.i=@bewilderbeest.net header.b="ONjRy3aH" Received: from hatter.bewilderbeest.net (unknown [IPv6:2602:61:712b:6300::2]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) (Authenticated sender: zev) by thorn.bewilderbeest.net (Postfix) with ESMTPSA id ED594D98; Wed, 7 Feb 2024 17:26:28 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bewilderbeest.net; s=thorn; t=1707355589; bh=3HS5yhO/DTt8/grju8Sqzw88K9FEC/162WIjUF71ihQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ONjRy3aHpvhgvdr/qZopPFDDk9gJT0Cc5cn1ptSvy4EpaL5K7ZCgYTwrWu+Pty3Wb FZJfZ784SCOysGyooOeqod7rgLZS9cjuzJ3WNFHtv5+CQyU9dcdZEKM4TWtPfJaG3N eFGWY8+D/ROgtTNbHFzNbcJwhr2E3vXpCERbyNMI= From: Zev Weiss To: Helge Deller , linux-parisc@vger.kernel.org, Florent Revest Cc: Zev Weiss , "James E.J. Bottomley" , "Mike Rapoport (IBM)" , Rick Edgecombe , "Borislav Petkov (AMD)" , Andrew Morton , Yang Shi , Stefan Roesch , Oleg Nesterov , David Hildenbrand , Josh Triplett , Ondrej Mosnacek , Miguel Ojeda , openbmc@lists.ozlabs.org, linux-kernel@vger.kernel.org, Sam James , stable@vger.kernel.org Subject: [PATCH 1/2] prctl: Generalize PR_SET_MDWE support check to be per-arch Date: Wed, 7 Feb 2024 17:26:19 -0800 Message-ID: <20240208012620.32604-5-zev@bewilderbeest.net> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20240208012620.32604-4-zev@bewilderbeest.net> References: <20240208012620.32604-4-zev@bewilderbeest.net> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" There exist systems other than PARISC where MDWE may not be feasible to support; rather than cluttering up the generic code with additional arch-specific logic let's add a generic function for checking MDWE support and allow each arch to override it as needed. Signed-off-by: Zev Weiss Cc: # v6.3+ --- arch/parisc/include/asm/mman.h | 14 ++++++++++++++ include/linux/mman.h | 8 ++++++++ kernel/sys.c | 7 +++++-- 3 files changed, 27 insertions(+), 2 deletions(-) create mode 100644 arch/parisc/include/asm/mman.h diff --git a/arch/parisc/include/asm/mman.h b/arch/parisc/include/asm/mman.h new file mode 100644 index 000000000000..47c5a1991d10 --- /dev/null +++ b/arch/parisc/include/asm/mman.h @@ -0,0 +1,14 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __ASM_MMAN_H__ +#define __ASM_MMAN_H__ + +#include + +/* PARISC cannot allow mdwe as it needs writable stacks */ +static inline bool arch_memory_deny_write_exec_supported(void) +{ + return false; +} +#define arch_memory_deny_write_exec_supported arch_memory_deny_write_exec_= supported + +#endif /* __ASM_MMAN_H__ */ diff --git a/include/linux/mman.h b/include/linux/mman.h index dc7048824be8..bcb201ab7a41 100644 --- a/include/linux/mman.h +++ b/include/linux/mman.h @@ -162,6 +162,14 @@ calc_vm_flag_bits(unsigned long flags) =20 unsigned long vm_commit_limit(void); =20 +#ifndef arch_memory_deny_write_exec_supported +static inline bool arch_memory_deny_write_exec_supported(void) +{ + return true; +} +#define arch_memory_deny_write_exec_supported arch_memory_deny_write_exec_= supported +#endif + /* * Denies creating a writable executable mapping or gaining executable per= missions. * diff --git a/kernel/sys.c b/kernel/sys.c index e219fcfa112d..8d4bd24fa555 100644 --- a/kernel/sys.c +++ b/kernel/sys.c @@ -2394,8 +2394,11 @@ static inline int prctl_set_mdwe(unsigned long bits,= unsigned long arg3, if (bits & PR_MDWE_NO_INHERIT && !(bits & PR_MDWE_REFUSE_EXEC_GAIN)) return -EINVAL; =20 - /* PARISC cannot allow mdwe as it needs writable stacks */ - if (IS_ENABLED(CONFIG_PARISC)) + /* + * EOPNOTSUPP might be more appropriate here in principle, but + * existing userspace depends on EINVAL specifically. + */ + if (!arch_memory_deny_write_exec_supported()) return -EINVAL; =20 current_bits =3D get_current_mdwe(); --=20 2.43.0 From nobody Sun Feb 8 04:13:04 2026 Received: from thorn.bewilderbeest.net (thorn.bewilderbeest.net [71.19.156.171]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 982781DFC9; Thu, 8 Feb 2024 01:26:35 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=71.19.156.171 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1707355597; cv=none; b=td1B8pyCURM0Bs9/QwDOuvLIEmpImmlLO57zsx4T6QYfIN9psv0sdW5vVs1PjeVSpXUiEAndZir8gqgTrH2IQMYVzut1b9AMEd7bEEuYG5IdVvGPWiaDA1wbA1oI2im+ljmBVu4dI7QagZJJ+vBzQkmiGeCTUkADeuK3wyP+Tmk= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1707355597; c=relaxed/simple; bh=OLe7cAlE7GWmn6Aw0nOYxdFDKvQ+HmBGQMrUtAdT8nM=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=pbYAdsZJd353StdQ1d4jrmMrmbILiRlVyOfRBYvrgl2tk/aHp3PBMEjQnwOCvfOp2eJvzw8m0VsLtmM/Oy4IHgnTpynlq7Xc/glLkCCyM6fJOm9IUUWat9XZYqSenohIru6SY/hjUfcK7xYw7GEDEYLMPRdv1KRHZxWI4+w5eq4= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=bewilderbeest.net; spf=pass smtp.mailfrom=bewilderbeest.net; dkim=pass (1024-bit key) header.d=bewilderbeest.net header.i=@bewilderbeest.net header.b=WE/8Lz4f; arc=none smtp.client-ip=71.19.156.171 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=bewilderbeest.net Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=bewilderbeest.net Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=bewilderbeest.net header.i=@bewilderbeest.net header.b="WE/8Lz4f" Received: from hatter.bewilderbeest.net (unknown [IPv6:2602:61:712b:6300::2]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) (Authenticated sender: zev) by thorn.bewilderbeest.net (Postfix) with ESMTPSA id 90C25DD9; Wed, 7 Feb 2024 17:26:29 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bewilderbeest.net; s=thorn; t=1707355589; bh=jCfZxrSPfJRHCvrnkx78xqXBFO8QXL5lwiLPbS+xTAw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=WE/8Lz4fbNW5hsXgLypZFn60E7qq3727+grkoIAgUAZO+kPRV+GimPEAfRtWnfs8N BHEObsnhOydmXdgmSyMAojdnhwMYrIFvSnPrwMl8MGW8gyVf330s4rIozE0T5/dEE9 47SLwGlLubpXFlRqB6hCTSQk3VHSnmIl2CW0Z4oQ= From: Zev Weiss To: Russell King , linux-arm-kernel@lists.infradead.org Cc: Zev Weiss , openbmc@lists.ozlabs.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: [PATCH 2/2] ARM: prctl: Reject PR_SET_MDWE on pre-ARMv6 Date: Wed, 7 Feb 2024 17:26:20 -0800 Message-ID: <20240208012620.32604-6-zev@bewilderbeest.net> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20240208012620.32604-4-zev@bewilderbeest.net> References: <20240208012620.32604-4-zev@bewilderbeest.net> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" On v5 and lower CPUs we can't provide MDWE protection, so ensure we fail any attempt to enable it via prctl(PR_SET_MDWE). Previously such an attempt would misleadingly succeed, leading to any subsequent mmap(PROT_READ|PROT_WRITE) or execve() failing unconditionally (the latter somewhat violently via force_fatal_sig(SIGSEGV) due to READ_IMPLIES_EXEC). Signed-off-by: Zev Weiss Cc: # v6.3+ --- arch/arm/include/asm/mman.h | 14 ++++++++++++++ 1 file changed, 14 insertions(+) create mode 100644 arch/arm/include/asm/mman.h diff --git a/arch/arm/include/asm/mman.h b/arch/arm/include/asm/mman.h new file mode 100644 index 000000000000..2189e507c8e0 --- /dev/null +++ b/arch/arm/include/asm/mman.h @@ -0,0 +1,14 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __ASM_MMAN_H__ +#define __ASM_MMAN_H__ + +#include +#include + +static inline bool arch_memory_deny_write_exec_supported(void) +{ + return cpu_architecture() >=3D CPU_ARCH_ARMv6; +} +#define arch_memory_deny_write_exec_supported arch_memory_deny_write_exec_= supported + +#endif /* __ASM_MMAN_H__ */ --=20 2.43.0