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 58097191F92 for ; Mon, 20 Oct 2025 15:44:20 +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=1760975060; cv=none; b=UXh7Lc8IF51E2BmXl9JNfL8BAXhongl1zoilWtTWOpilQYZow2T2JI2lODNETriyr9TypgErWDA8lRQ8b/qTY66Asx3L8Tqq7SqRqinljiMmg51UGlOMyqSiRIFxqCfv53k97uBqPJhyOAIrSuPhprkTTW6vlI/3j3ZT0FRVVdE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760975060; c=relaxed/simple; bh=LkvrscrIBp06mopZAl9cfw1ZExmnu5oyZTd/waLUHQw=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=NPNynJUuFQt3XcgSBtOyPS7If88vGQnGJKzHpPU9hw6x5T3/DPKg8oGNxQAlclJmCobAEwKUA7QIl1jxsHe8ejmd5Z3u3RIxIDjXidYDVWKDjH4hIR87NJ5AOyDqjCfA5AX2X0EZ9R/zXeFvydtJCezXLap89XrbOyGyV2MuzPE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=na8Bjarr; 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="na8Bjarr" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2CE34C4CEF9; Mon, 20 Oct 2025 15:44:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1760975059; bh=LkvrscrIBp06mopZAl9cfw1ZExmnu5oyZTd/waLUHQw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=na8BjarrUoXJdXHh0u2aOwPxxz/4lCYEIzl/uUjMykRLOBnGu+S5/Jy9BPxgQNcGc 5V+IskeMEXHHbxzYej9bV5zq3A78U2Xd9RgX6xAkKp8DxMRVUop3FM7xB3THcwRfBL B/cwpDA3EKfLfbkgAmL6+cLn3JSybPRp8AA/DXJO8zd4O8GEo2UM1LxIkq8nB80r/f iPWFPcJCzcAIw90eb0oqi9DcovuMf1HX7tKUSc3L0Q4w31vdTInz4iBnH82Rb6S9ac c5icu9bX9LqAY/omt61ZglvRG9ydAk47RR8pms5LnoMPVImK78l4ZybUyt5xkld5iV 5yJPpJzTQXNmA== From: Sasha Levin To: stable@vger.kernel.org Cc: Kuniyuki Iwashima , "Matthieu Baerts (NGI0)" , Eric Dumazet , Jakub Kicinski , Sasha Levin Subject: [PATCH 6.12.y 7/8] mptcp: Use __sk_dst_get() and dst_dev_rcu() in mptcp_active_enable(). Date: Mon, 20 Oct 2025 11:44:08 -0400 Message-ID: <20251020154409.1823664-7-sashal@kernel.org> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20251020154409.1823664-1-sashal@kernel.org> References: <2025101604-chamber-playhouse-5278@gregkh> <20251020154409.1823664-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Kuniyuki Iwashima [ Upstream commit 893c49a78d9f85e4b8081b908fb7c407d018106a ] mptcp_active_enable() is called from subflow_finish_connect(), which is icsk->icsk_af_ops->sk_rx_dst_set() and it's not always under RCU. Using sk_dst_get(sk)->dev could trigger UAF. Let's use __sk_dst_get() and dst_dev_rcu(). Fixes: 27069e7cb3d1 ("mptcp: disable active MPTCP in case of blackhole") Signed-off-by: Kuniyuki Iwashima Reviewed-by: Matthieu Baerts (NGI0) Reviewed-by: Eric Dumazet Link: https://patch.msgid.link/20250916214758.650211-8-kuniyu@google.com Signed-off-by: Jakub Kicinski Stable-dep-of: 833d4313bc1e ("mptcp: reset blackhole on success with non-loopback ifaces") Signed-off-by: Sasha Levin --- net/mptcp/ctrl.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) diff --git a/net/mptcp/ctrl.c b/net/mptcp/ctrl.c index 6a97d11bda7e2..9e1f61b02a66e 100644 --- a/net/mptcp/ctrl.c +++ b/net/mptcp/ctrl.c @@ -381,12 +381,15 @@ void mptcp_active_enable(struct sock *sk) struct mptcp_pernet *pernet = mptcp_get_pernet(sock_net(sk)); if (atomic_read(&pernet->active_disable_times)) { - struct dst_entry *dst = sk_dst_get(sk); + struct net_device *dev; + struct dst_entry *dst; - if (dst && dst->dev && (dst->dev->flags & IFF_LOOPBACK)) + rcu_read_lock(); + dst = __sk_dst_get(sk); + dev = dst ? dst_dev_rcu(dst) : NULL; + if (dev && (dev->flags & IFF_LOOPBACK)) atomic_set(&pernet->active_disable_times, 0); - - dst_release(dst); + rcu_read_unlock(); } } -- 2.51.0