From nobody Mon Sep 22 04:32:31 2025 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 94AFEECAAD5 for ; Mon, 29 Aug 2022 11:03:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229710AbiH2LDu (ORCPT ); Mon, 29 Aug 2022 07:03:50 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42902 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229997AbiH2LCk (ORCPT ); Mon, 29 Aug 2022 07:02:40 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C3A9661D7E; Mon, 29 Aug 2022 04:02:23 -0700 (PDT) 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 18178B80EC8; Mon, 29 Aug 2022 11:02:22 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 76B67C433D6; Mon, 29 Aug 2022 11:02:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1661770940; bh=HSivPwEJNBD0H6WSrupOZVMQuBQR22Uv3zE+0MRH/yI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=u0kpHE0We/Gb0LK7m3+hEY0/GcSJARk9x8E09m5ni2SeW7hLkIMM6+WKzsj9OEqey Lh18zEANf2HHWuQiBLWJljsa5CgvGbiKlgVJjcE8hYolugbIIHAFC1qZ32VWbSVhs0 41FlqqvsB26Q/7FmTMOLuABSwIewFbeVmFysKDxA= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Steffen Klassert , Daniel Borkmann , Nikolay Aleksandrov , Sasha Levin Subject: [PATCH 5.15 029/136] xfrm: policy: fix metadata dst->dev xmit null pointer dereference Date: Mon, 29 Aug 2022 12:58:16 +0200 Message-Id: <20220829105805.769776893@linuxfoundation.org> X-Mailer: git-send-email 2.37.2 In-Reply-To: <20220829105804.609007228@linuxfoundation.org> References: <20220829105804.609007228@linuxfoundation.org> User-Agent: quilt/0.67 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: Nikolay Aleksandrov [ Upstream commit 17ecd4a4db4783392edd4944f5e8268205083f70 ] When we try to transmit an skb with metadata_dst attached (i.e. dst->dev =3D=3D NULL) through xfrm interface we can hit a null pointer dereference[1] in xfrmi_xmit2() -> xfrm_lookup_with_ifid() due to the check for a loopback skb device when there's no policy which dereferences dst->dev unconditionally. Not having dst->dev can be interepreted as it not being a loopback device, so just add a check for a null dst_orig->dev. With this fix xfrm interface's Tx error counters go up as usual. [1] net-next calltrace captured via netconsole: BUG: kernel NULL pointer dereference, address: 00000000000000c0 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 0 P4D 0 Oops: 0000 [#1] PREEMPT SMP CPU: 1 PID: 7231 Comm: ping Kdump: loaded Not tainted 5.19.0+ #24 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.0-1.fc36 04= /01/2014 RIP: 0010:xfrm_lookup_with_ifid+0x5eb/0xa60 Code: 8d 74 24 38 e8 26 a4 37 00 48 89 c1 e9 12 fc ff ff 49 63 ed 41 83 f= d be 0f 85 be 01 00 00 41 be ff ff ff ff 45 31 ed 48 8b 03 80 c0 00 00= 00 08 75 0f 41 80 bc 24 19 0d 00 00 01 0f 84 1e 02 RSP: 0018:ffffb0db82c679f0 EFLAGS: 00010246 RAX: 0000000000000000 RBX: ffffd0db7fcad430 RCX: ffffb0db82c67a10 RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffb0db82c67a80 RBP: ffffb0db82c67a80 R08: ffffb0db82c67a14 R09: 0000000000000000 R10: 0000000000000000 R11: ffff8fa449667dc8 R12: ffffffff966db880 R13: 0000000000000000 R14: 00000000ffffffff R15: 0000000000000000 FS: 00007ff35c83f000(0000) GS:ffff8fa478480000(0000) knlGS:0000000000000= 000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00000000000000c0 CR3: 000000001ebb7000 CR4: 0000000000350ee0 Call Trace: xfrmi_xmit+0xde/0x460 ? tcf_bpf_act+0x13d/0x2a0 dev_hard_start_xmit+0x72/0x1e0 __dev_queue_xmit+0x251/0xd30 ip_finish_output2+0x140/0x550 ip_push_pending_frames+0x56/0x80 raw_sendmsg+0x663/0x10a0 ? try_charge_memcg+0x3fd/0x7a0 ? __mod_memcg_lruvec_state+0x93/0x110 ? sock_sendmsg+0x30/0x40 sock_sendmsg+0x30/0x40 __sys_sendto+0xeb/0x130 ? handle_mm_fault+0xae/0x280 ? do_user_addr_fault+0x1e7/0x680 ? kvm_read_and_reset_apf_flags+0x3b/0x50 __x64_sys_sendto+0x20/0x30 do_syscall_64+0x34/0x80 entry_SYSCALL_64_after_hwframe+0x46/0xb0 RIP: 0033:0x7ff35cac1366 Code: eb 0b 00 f7 d8 64 89 02 48 c7 c0 ff ff ff ff eb b8 0f 1f 00 41 89 c= a 64 8b 04 25 18 00 00 00 85 c0 75 11 b8 2c 00 00 00 0f 05 <48> 3d 00 f0 ff= ff 77 72 c3 90 55 48 83 ec 30 44 89 4c 24 2c 4c 89 RSP: 002b:00007fff738e4028 EFLAGS: 00000246 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 00007fff738e57b0 RCX: 00007ff35cac1366 RDX: 0000000000000040 RSI: 0000557164e4b450 RDI: 0000000000000003 RBP: 0000557164e4b450 R08: 00007fff738e7a2c R09: 0000000000000010 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000040 R13: 00007fff738e5770 R14: 00007fff738e4030 R15: 0000001d00000001 Modules linked in: netconsole veth br_netfilter bridge bonding virtio_net= [last unloaded: netconsole] CR2: 00000000000000c0 CC: Steffen Klassert CC: Daniel Borkmann Fixes: 2d151d39073a ("xfrm: Add possibility to set the default to block if = we have no policy") Signed-off-by: Nikolay Aleksandrov Signed-off-by: Steffen Klassert Signed-off-by: Sasha Levin --- net/xfrm/xfrm_policy.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c index 036d7de164914..ba58b963f4827 100644 --- a/net/xfrm/xfrm_policy.c +++ b/net/xfrm/xfrm_policy.c @@ -3162,7 +3162,7 @@ struct dst_entry *xfrm_lookup_with_ifid(struct net *n= et, return dst; =20 nopol: - if (!(dst_orig->dev->flags & IFF_LOOPBACK) && + if ((!dst_orig->dev || !(dst_orig->dev->flags & IFF_LOOPBACK)) && net->xfrm.policy_default[dir] =3D=3D XFRM_USERPOLICY_BLOCK) { err =3D -EPERM; goto error; --=20 2.35.1