From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793209424; b=IGkg02rXlxPmm38VZhRf6Touyoq+NhiARw8XngDGiL+H6v4deKQaxH+EYypEXW5EuP09 l6UUMzSyAcpnBR6IvmNR7l1SXc5P32PESv57vuq18EHB4Lm7blo6dYx3Y2FxTx63EY6P7 E1p01QlLfvY6BDlignw4X+3Jffv5hdEkUFJCij7dUR19nhW/k7a2wkTmk/pV7S2brWUDm TAKxmtfj6/4yUG70fFxi6VcaHSbV+6m5TOHqFB1SzX/pJUOq+Nrg+AlbovDDZ0svrD3wt muXGNM3fEo4vwP2DqNv7pyY+kLmf2fazErf508NI2C8qXxx4RcLhTtYnIjdXPy9XVqg== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793209424; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:User-Agent:X-stable:X-Patchwork-Hint: MIME-Version:Content-Transfer-Encoding; bh=oRz83AL2Elqme3APEbng+cTZMFjRq3F/o1XQ+C+KFXo=; b=TA7ZCaZ9ScMNfdElUxZ8f77ocz6BWwXIvUAIDywJAiTRRacQ27GOxqfmhCvl//eay6rV cIQKEoiDATu5UMy6XKVeMbZ8XB47RGr2xBFDXFZKl7mu/jdf0OG1rK3rRf2b5krxgEl5X I+6OKDRehcH5Q6U/Rz6aVYMxD7X8J7PuAtrJCpONjPBT34sM663A1+3cEtunN4PS2U4Co pD1On4fnpjOZ6vViWrgXdgHmDx25zkGdz6zudG8RqfrWEMkO3CyIvjWS3vRMWRuA+66eW lfyFiOI3z7zO8k+Oe5YNOuT0lPtO/cnwnl2PyuUX/bH9PVnV2pQ4E/hvP3Dp2Y9Pj+g== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b="0Ppa/2hZ"; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E5733606A31C; Wed, 28 Oct 2026 17:43:43 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=0Ppa/2hZ Received: by smtp.kernel.org (Postfix) with ESMTPSA id 123C01F01825; Wed, 28 Oct 2026 17:43:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1793209423; bh=oRz83AL2Elqme3APEbng+cTZMFjRq3F/o1XQ+C+KFXo=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=0Ppa/2hZn6LUzL60Xr1n9TGvjjRgyg29f39qeKsST2Ldj9djta7Pd/A2C5Opu6lUW b7oz8pv7p+UrxDuDcreNICcUZE01flgEJdU+8E3hCtgFTL0tXiV/+Z5nyw+p5/sCfx MR7DVJAtbw9DJC6qTa3G3Mo2hpluf2RYGnKRg7aM= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Eric Dumazet , AutonomousCodeSecurity@microsoft.com, "Cen Zhang (Microsoft Security FORGE Labs)" , Jiayuan Chen , "Matthieu Baerts (NGI0)" , Jakub Kicinski Subject: [PATCH 5.10 464/516] tcp: fix use-after-free in do_tcp_getsockopt(TCP_CC_INFO) Date: Wed, 28 Oct 2026 18:00:16 +0100 Message-ID: <20261028170014.472340244@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261028170003.522232767@linuxfoundation.org> References: <20261028170003.522232767@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore X-Mailing-List: patches@lists.linux.dev List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.10-stable review patch. If anyone has any objections, please let me know. ------------------ From: Cen Zhang (Microsoft Security FORGE Labs) commit 385e474086c2e7e29e2dded690be40dc273e20ee upstream. 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. Fixes: 0baf26b0fcd7 ("bpf: tcp: Support tcp_congestion_ops in bpf") Suggested-by: Eric Dumazet Cc: AutonomousCodeSecurity@microsoft.com Cc: stable@vger.kernel.org Reviewed-by: Eric Dumazet Signed-off-by: Cen Zhang (Microsoft Security FORGE Labs) Reviewed-by: Jiayuan Chen Reviewed-by: Matthieu Baerts (NGI0) Link: https://patch.msgid.link/65fd3816ed5d541d9edd4bf4fcf97104a2cf907a.1787870710.git.blbllhy@gmail.com Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman --- net/ipv4/tcp.c | 4 +++- net/ipv4/tcp_dctcp.c | 2 +- 2 files changed, 4 insertions(+), 2 deletions(-) --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -3818,9 +3818,11 @@ static int do_tcp_getsockopt(struct sock if (get_user(len, optlen)) return -EFAULT; - ca_ops = icsk->icsk_ca_ops; + rcu_read_lock(); + ca_ops = READ_ONCE(icsk->icsk_ca_ops); if (ca_ops && ca_ops->get_info) sz = ca_ops->get_info(sk, ~0U, &attr, &info); + rcu_read_unlock(); len = min_t(unsigned int, len, sz); if (put_user(len, optlen)) --- a/net/ipv4/tcp_dctcp.c +++ b/net/ipv4/tcp_dctcp.c @@ -201,7 +201,7 @@ static size_t dctcp_get_info(struct sock if (ext & (1 << (INET_DIAG_DCTCPINFO - 1)) || ext & (1 << (INET_DIAG_VEGASINFO - 1))) { memset(&info->dctcp, 0, sizeof(info->dctcp)); - if (inet_csk(sk)->icsk_ca_ops != &dctcp_reno) { + if (READ_ONCE(inet_csk(sk)->icsk_ca_ops) != &dctcp_reno) { info->dctcp.dctcp_enabled = 1; info->dctcp.dctcp_ce_state = (u16) ca->ce_state; info->dctcp.dctcp_alpha = ca->dctcp_alpha;