From: Matthieu Baerts <matttbe@kernel.org>
To: "Cen Zhang (Microsoft)" <blbllhy@gmail.com>,
edumazet@google.com, ncardwell@google.com, davem@davemloft.net,
kuba@kernel.org, pabeni@redhat.com
Cc: kuniyu@google.com, horms@kernel.org, martineau@kernel.org,
geliang@kernel.org, yhs@fb.com, kafai@fb.com, andriin@fb.com,
ast@kernel.org, netdev@vger.kernel.org, mptcp@lists.linux.dev,
bpf@vger.kernel.org, linux-kernel@vger.kernel.org,
AutonomousCodeSecurity@microsoft.com, xmei5@asu.edu,
tgopinath@linux.microsoft.com, kys@microsoft.com,
stable@vger.kernel.org
Subject: Re: [PATCH net v3 2/2] tcp: fix use-after-free in do_tcp_getsockopt(TCP_CC_INFO)
Date: Fri, 28 Aug 2026 11:42:04 +0200 [thread overview]
Message-ID: <782901a4-1c5a-4d9b-9baa-c8e6c31bf971@kernel.org> (raw)
In-Reply-To: <65fd3816ed5d541d9edd4bf4fcf97104a2cf907a.1787870710.git.blbllhy@gmail.com>
On 28/08/2026 01:55, Cen Zhang (Microsoft) wrote:
> From: "Cen Zhang (Microsoft Security FORGE Labs)" <blbllhy@gmail.com>
>
> do_tcp_getsockopt() reads icsk->icsk_ca_ops and dereferences the
> get_info function pointer without rcu_read_lock(). With BPF struct_ops
> congestion control, ca_ops can point to dynamically allocated memory
> that is freed concurrently, resulting in a use-after-free when the
> kernel dereferences or calls through the stale pointer.
>
> BUG: KASAN: slab-use-after-free in do_tcp_getsockopt+0x2037/0x23e0
> Read of size 8 at addr ffff888013701258 by task exploit/149
> do_tcp_getsockopt+0x2037/0x23e0 (net/ipv4/tcp.c:4564)
> tcp_getsockopt+0x91/0xf0
> __sys_getsockopt+0xf7/0x170
>
> Fix this by wrapping the ca_ops load and get_info call within
> rcu_read_lock()/rcu_read_unlock(), and using READ_ONCE() to load
> the icsk_ca_ops pointer.
Reviewed-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Cheers,
Matt
--
Sponsored by the NGI0 Core fund.
prev parent reply other threads:[~2026-08-28 9:42 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-08-27 23:55 [PATCH net v3 0/2] tcp: fix use-after-free in do_tcp_getsockopt() Cen Zhang (Microsoft)
2026-08-27 23:55 ` [PATCH net v3 1/2] tcp: fix use-after-free in do_tcp_getsockopt(TCP_CONGESTION) Cen Zhang (Microsoft)
2026-08-28 3:26 ` Jiayuan Chen
2026-08-28 9:41 ` Matthieu Baerts
2026-08-28 12:38 ` Breno Leitao
2026-08-28 13:02 ` Cen Zhang (Microsoft)
2026-08-28 14:17 ` Breno Leitao
2026-08-28 23:55 ` sashiko-bot
2026-08-27 23:55 ` [PATCH net v3 2/2] tcp: fix use-after-free in do_tcp_getsockopt(TCP_CC_INFO) Cen Zhang (Microsoft)
2026-08-28 3:14 ` Jiayuan Chen
2026-08-28 9:42 ` Matthieu Baerts [this message]
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