From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 7384183A18 for ; Wed, 8 May 2024 13:46:36 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1715175996; cv=none; b=afulsFXLeCB4ahQgPKNTqTCTQBiKBI8E5c3U1wrd0U47H+SCvgswYrlzlACNB01/2TwpTF39xzkjX8OoJQ/uGt5GRw8FeqS9jXyomQxXikpCy57qDLBMprGBx93s4JXv4wtCfotieHdrse8S/cF/nTRTfY06JVQOp+oyPrSLcoM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1715175996; c=relaxed/simple; bh=GdixQsgXvC6tXH8Ww9zrCzm6z3xMTX7yN34V5Eukft0=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=abmJyPHhDpoFH3MJ51OMn4LlbjCkwLtfaf/CdwemFQrTvvYayqb+O0G9pEfF0UCUTAUvIF7PMkLDiY0RO+jqj5TZDv8LDNiK4TTEc8KlQjagn08wjgvfsLA98YGgv3tDulLFUo8Iiy3cFo6fWuMd6VQH8ZM9aBHHxwKtKgMlVzk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=aCT7PrIt; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="aCT7PrIt" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7647DC113CC; Wed, 8 May 2024 13:46:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1715175996; bh=GdixQsgXvC6tXH8Ww9zrCzm6z3xMTX7yN34V5Eukft0=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=aCT7PrItNGdOtULlPqF/Ai9WyjvuHJafdOVxGm6edf6ZkZKQFYkC9wWMaEWBIAKG1 9zpzYrUBtODocSAdR2KMBBGhMmShz8i0hvww8BMYqUsWBOS5xL6uIJIS7MHO8IF2pi 1p9jFETanG7vXm6wNS8tzRQyHMMf1nAK14mXVXs2x5Lcj5/d0Ni5yVjzLzy5UGGC0i theifWkUsTiGFbrlDzZe9ksP84zh1b3/ZhwgSqx3Lve65vb/rhofji/geUGyNjJGpK Y+6Ia5RX6/WaeSUcOkWoE4K1JViSE691AgJyLDSixDAU5el5ap6wH272eUWuZVW8j+ b0TPdO9dtEuGA== Date: Wed, 8 May 2024 14:46:32 +0100 From: Simon Horman To: Eric Dumazet Cc: "David S . Miller" , Jakub Kicinski , Paolo Abeni , David Ahern , netdev@vger.kernel.org, eric.dumazet@gmail.com Subject: Re: [PATCH net] ipv6: fib6_rules: avoid possible NULL dereference in fib6_rule_action() Message-ID: <20240508134632.GF1736038@kernel.org> References: <20240507163145.835254-1-edumazet@google.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240507163145.835254-1-edumazet@google.com> On Tue, May 07, 2024 at 04:31:45PM +0000, Eric Dumazet wrote: > syzbot is able to trigger the following crash [1], > caused by unsafe ip6_dst_idev() use. > > Indeed ip6_dst_idev() can return NULL, and must always be checked. > > [1] > > Oops: general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN PTI > KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007] > CPU: 0 PID: 31648 Comm: syz-executor.0 Not tainted 6.9.0-rc4-next-20240417-syzkaller #0 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024 > RIP: 0010:__fib6_rule_action net/ipv6/fib6_rules.c:237 [inline] > RIP: 0010:fib6_rule_action+0x241/0x7b0 net/ipv6/fib6_rules.c:267 > Code: 02 00 00 49 8d 9f d8 00 00 00 48 89 d8 48 c1 e8 03 42 80 3c 20 00 74 08 48 89 df e8 f9 32 bf f7 48 8b 1b 48 89 d8 48 c1 e8 03 <42> 80 3c 20 00 74 08 48 89 df e8 e0 32 bf f7 4c 8b 03 48 89 ef 4c > RSP: 0018:ffffc9000fc1f2f0 EFLAGS: 00010246 > RAX: 0000000000000000 RBX: 0000000000000000 RCX: 1a772f98c8186700 > RDX: 0000000000000003 RSI: ffffffff8bcac4e0 RDI: ffffffff8c1f9760 > RBP: ffff8880673fb980 R08: ffffffff8fac15ef R09: 1ffffffff1f582bd > R10: dffffc0000000000 R11: fffffbfff1f582be R12: dffffc0000000000 > R13: 0000000000000080 R14: ffff888076509000 R15: ffff88807a029a00 > FS: 00007f55e82ca6c0(0000) GS:ffff8880b9400000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 0000001b31d23000 CR3: 0000000022b66000 CR4: 00000000003506f0 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > Call Trace: > > fib_rules_lookup+0x62c/0xdb0 net/core/fib_rules.c:317 > fib6_rule_lookup+0x1fd/0x790 net/ipv6/fib6_rules.c:108 > ip6_route_output_flags_noref net/ipv6/route.c:2637 [inline] > ip6_route_output_flags+0x38e/0x610 net/ipv6/route.c:2649 > ip6_route_output include/net/ip6_route.h:93 [inline] > ip6_dst_lookup_tail+0x189/0x11a0 net/ipv6/ip6_output.c:1120 > ip6_dst_lookup_flow+0xb9/0x180 net/ipv6/ip6_output.c:1250 > sctp_v6_get_dst+0x792/0x1e20 net/sctp/ipv6.c:326 > sctp_transport_route+0x12c/0x2e0 net/sctp/transport.c:455 > sctp_assoc_add_peer+0x614/0x15c0 net/sctp/associola.c:662 > sctp_connect_new_asoc+0x31d/0x6c0 net/sctp/socket.c:1099 > __sctp_connect+0x66d/0xe30 net/sctp/socket.c:1197 > 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: 5e5f3f0f8013 ("[IPV6] ADDRCONF: Convert ipv6_get_saddr() to ipv6_dev_get_saddr().") > Signed-off-by: Eric Dumazet Reviewed-by: Simon Horman