From: David Ahern <dsahern@kernel.org>
To: Eric Dumazet <edumazet@google.com>,
"David S . Miller" <davem@davemloft.net>,
Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>
Cc: netdev@vger.kernel.org, eric.dumazet@gmail.com
Subject: Re: [PATCH net] ipv6: fib6_rules: avoid possible NULL dereference in fib6_rule_action()
Date: Wed, 8 May 2024 09:02:53 -0600 [thread overview]
Message-ID: <ce6e18fb-5d5f-46cd-b7fe-16982a41cda8@kernel.org> (raw)
In-Reply-To: <20240507163145.835254-1-edumazet@google.com>
On 5/7/24 10:31 AM, 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:
> <TASK>
> 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 <edumazet@google.com>
> ---
> net/ipv6/fib6_rules.c | 6 +++++-
> 1 file changed, 5 insertions(+), 1 deletion(-)
>
Reviewed-by: David Ahern <dsahern@kernel.org>
next prev parent reply other threads:[~2024-05-08 15:02 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-05-07 16:31 [PATCH net] ipv6: fib6_rules: avoid possible NULL dereference in fib6_rule_action() Eric Dumazet
2024-05-08 13:46 ` Simon Horman
2024-05-08 15:02 ` David Ahern [this message]
2024-05-09 2:00 ` patchwork-bot+netdevbpf
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