From patchwork Fri Jul 5 21:17:41 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Vinicius Peixoto X-Patchwork-Id: 1957451 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@legolas.ozlabs.org Authentication-Results: legolas.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=lists.ubuntu.com (client-ip=185.125.189.65; helo=lists.ubuntu.com; envelope-from=kernel-team-bounces@lists.ubuntu.com; receiver=patchwork.ozlabs.org) Received: from lists.ubuntu.com (lists.ubuntu.com [185.125.189.65]) (using TLSv1.2 with cipher ECDHE-ECDSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by legolas.ozlabs.org (Postfix) with ESMTPS id 4WG5w00YW5z1xr3 for ; Sat, 6 Jul 2024 07:18:07 +1000 (AEST) Received: from localhost ([127.0.0.1] helo=lists.ubuntu.com) by lists.ubuntu.com with esmtp (Exim 4.86_2) (envelope-from ) id 1sPqJb-0004MX-1O; Fri, 05 Jul 2024 21:17:59 +0000 Received: from smtp-relay-internal-1.internal ([10.131.114.114] helo=smtp-relay-internal-1.canonical.com) by lists.ubuntu.com with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.86_2) (envelope-from ) id 1sPqJZ-0004MH-9a for kernel-team@lists.ubuntu.com; Fri, 05 Jul 2024 21:17:57 +0000 Received: from mail-io1-f72.google.com (mail-io1-f72.google.com [209.85.166.72]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by smtp-relay-internal-1.canonical.com (Postfix) with ESMTPS id 1309D3F0D2 for ; Fri, 5 Jul 2024 21:17:57 +0000 (UTC) Received: by mail-io1-f72.google.com with SMTP id ca18e2360f4ac-7f3c9b72aebso243277639f.3 for ; Fri, 05 Jul 2024 14:17:57 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1720214275; x=1720819075; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=fV70werK5hdgnoreFdtfDrW87b6m2C+D3AdFka6HgM4=; b=mQIORSLqsgu1SMgP6mJ7kjj3dtQ12hMgHupf6gW1nyyhOkqN2JOlqtU1lroEe6PThw xZnpA4AEeXL7KRoTtjfikVMg+zFFi3rJdxNKD9weHjbv7XZgCJtofWFKwJ0iK2eRytsO IzyLYYz7IKcR1+BemlFbBKOWLE9kR0EvQcwE0ae7uX3mmSH5kSOKhJ2tlnuVDht+yYNd Filv2nf6I7VlaK5QqS8aFzv0ZLvx79npDMlibjwfTZH1I0Pv2iiVhc0up/8jseHFNIJZ Of29hq16WplW0STedY4oh64/jS6gd0PgkOAn6zCvsqeB2MGlXA4yleXG2Jrz11y1DXCb gAVg== X-Gm-Message-State: AOJu0YyVsBysit5hRbY+3Whw3kE5upinEMcYZAK76w5oBzYpbygn5YAH PfXWPY5VTljJT5XUmhMKol23tLH2f8AZkO6RLWrkZE79eLaNsNCRuc01SMMM6qOikWw63/sAb+y 6JosvXbr25QuUAYMZGHZKdKm9n4M8eR4/JOe64c0XUx1ybzxFcEv4KlrFo5H+qEBfpKGjK8I6qS EN/OVUAxtBczQ7 X-Received: by 2002:a05:6e02:170c:b0:383:8ec6:6d0e with SMTP id e9e14a558f8ab-38398a018e7mr74774735ab.8.1720214275428; Fri, 05 Jul 2024 14:17:55 -0700 (PDT) X-Google-Smtp-Source: AGHT+IHJwpAyLFSg4ce5bSXHK4FoK302GTOiOc0osD2U2ksEwjqdNbyl19G0O8Ey/Cy/e+Idvd5wRw== X-Received: by 2002:a05:6e02:170c:b0:383:8ec6:6d0e with SMTP id e9e14a558f8ab-38398a018e7mr74774575ab.8.1720214275082; Fri, 05 Jul 2024 14:17:55 -0700 (PDT) Received: from canonical.com ([2801:8a:c811:1:9001:2cf:62b6:a60]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-7080498a3besm14488921b3a.196.2024.07.05.14.17.53 for (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 05 Jul 2024 14:17:54 -0700 (PDT) From: Vinicius Peixoto To: kernel-team@lists.ubuntu.com Subject: [SRU][J/F][PATCH 1/1] ipv6: prevent NULL dereference in ip6_output() Date: Fri, 5 Jul 2024 18:17:41 -0300 Message-ID: <20240705211741.9334-2-vinicius.peixoto@canonical.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20240705211741.9334-1-vinicius.peixoto@canonical.com> References: <20240705211741.9334-1-vinicius.peixoto@canonical.com> MIME-Version: 1.0 X-BeenThere: kernel-team@lists.ubuntu.com X-Mailman-Version: 2.1.20 Precedence: list List-Id: Kernel team discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: kernel-team-bounces@lists.ubuntu.com Sender: "kernel-team" From: Eric Dumazet According to syzbot, there is a chance that ip6_dst_idev() returns NULL in ip6_output(). Most places in IPv6 stack deal with a NULL idev just fine, but not here. syzbot reported: general protection fault, probably for non-canonical address 0xdffffc00000000bc: 0000 [#1] PREEMPT SMP KASAN PTI KASAN: null-ptr-deref in range [0x00000000000005e0-0x00000000000005e7] CPU: 0 PID: 9775 Comm: syz-executor.4 Not tainted 6.9.0-rc5-syzkaller-00157-g6a30653b604a #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024 RIP: 0010:ip6_output+0x231/0x3f0 net/ipv6/ip6_output.c:237 Code: 3c 1e 00 49 89 df 74 08 4c 89 ef e8 19 58 db f7 48 8b 44 24 20 49 89 45 00 49 89 c5 48 8d 9d e0 05 00 00 48 89 d8 48 c1 e8 03 <42> 0f b6 04 38 84 c0 4c 8b 74 24 28 0f 85 61 01 00 00 8b 1b 31 ff RSP: 0018:ffffc9000927f0d8 EFLAGS: 00010202 RAX: 00000000000000bc RBX: 00000000000005e0 RCX: 0000000000040000 RDX: ffffc900131f9000 RSI: 0000000000004f47 RDI: 0000000000004f48 RBP: 0000000000000000 R08: ffffffff8a1f0b9a R09: 1ffffffff1f51fad R10: dffffc0000000000 R11: fffffbfff1f51fae R12: ffff8880293ec8c0 R13: ffff88805d7fc000 R14: 1ffff1100527d91a R15: dffffc0000000000 FS: 00007f135c6856c0(0000) GS:ffff8880b9400000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000020000080 CR3: 0000000064096000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: NF_HOOK include/linux/netfilter.h:314 [inline] ip6_xmit+0xefe/0x17f0 net/ipv6/ip6_output.c:358 sctp_v6_xmit+0x9f2/0x13f0 net/sctp/ipv6.c:248 sctp_packet_transmit+0x26ad/0x2ca0 net/sctp/output.c:653 sctp_packet_singleton+0x22c/0x320 net/sctp/outqueue.c:783 sctp_outq_flush_ctrl net/sctp/outqueue.c:914 [inline] sctp_outq_flush+0x6d5/0x3e20 net/sctp/outqueue.c:1212 sctp_side_effects net/sctp/sm_sideeffect.c:1198 [inline] sctp_do_sm+0x59cc/0x60c0 net/sctp/sm_sideeffect.c:1169 sctp_primitive_ASSOCIATE+0x95/0xc0 net/sctp/primitive.c:73 __sctp_connect+0x9cd/0xe30 net/sctp/socket.c:1234 sctp_connect net/sctp/socket.c:4819 [inline] sctp_inet_connect+0x149/0x1f0 net/sctp/socket.c:4834 __sys_connect_file net/socket.c:2048 [inline] __sys_connect+0x2df/0x310 net/socket.c:2065 __do_sys_connect net/socket.c:2075 [inline] __se_sys_connect net/socket.c:2072 [inline] __x64_sys_connect+0x7a/0x90 net/socket.c:2072 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf5/0x240 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f Fixes: 778d80be5269 ("ipv6: Add disable_ipv6 sysctl to disable IPv6 operaion on specific interface.") Reported-by: syzbot Signed-off-by: Eric Dumazet Reviewed-by: Larysa Zaremba Link: https://lore.kernel.org/r/20240507161842.773961-1-edumazet@google.com Signed-off-by: Jakub Kicinski CVE-2024-36901 (backported from commit 4db783d68b9b39a411a96096c10828ff5dfada7a) [vpeixoto: upstream commit 5e187189ec32 ("net: ip: add skb drop reasons for ip egress path)" does not exist in this kernel and makes a superfluous change that introduces a context conflict at the `kfree_skb` call.] Signed-off-by: Vinicius Peixoto --- net/ipv6/ip6_output.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c index 3b1efab423b8b..e72b47bf8af97 100644 --- a/net/ipv6/ip6_output.c +++ b/net/ipv6/ip6_output.c @@ -221,7 +221,7 @@ int ip6_output(struct net *net, struct sock *sk, struct sk_buff *skb) skb->protocol = htons(ETH_P_IPV6); skb->dev = dev; - if (unlikely(idev->cnf.disable_ipv6)) { + if (unlikely(!idev || READ_ONCE(idev->cnf.disable_ipv6))) { IP6_INC_STATS(net, idev, IPSTATS_MIB_OUTDISCARDS); kfree_skb(skb); return 0;