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=1794520669; b=MhWCU1mhwUSc0xNV6ymZh54nDyEJq/gvqJ2vCNkoxtGel1sz2SWc8O4vAOLoP1+Dz0Uy NgM4L0hoyVF3h72o2pgYfS8jmQp6fuUd1nalxoawFRIuBkOQPKbNf3K0m/ipTuRbdQiAr u3jR+s3htAULskeJnGsaRTLvdYbc4nMsgOaS6it7hEHzjsQTfUUdpa4GUwwTzNRHATO71 yTLLSRFzhBbOKxgyOWcccabHEnf5YlL1CfhGW0jpUkef8/5nSWzIi4Wu1pgLRI6V1tAI+ 8RRPaCV7HzQLy4pKBWWDxoBd8FadIk8avYVht+1GPFalRoHdicbKAfHnEIiXzCpzAkA== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794520669; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:MIME-Version:Content-Transfer-Encoding; bh=YIcAatM9lLgopjMYOpAidm6KFqZNJ7St4aXap4jyYYI=; b=CgLgRXfuNLFZJdCMxMfpx6ViItI0PGQWDYbxcfUOxn5ehf2J5jpTpFTf8kVAfWQUEu2M GfmWXGmWY1218MAm/5s/anUTYy3QKv7kiXoPz5bl2VTGS/eTqd98TVoPONfmNMnD+bMjq L+ByUSSWX8f+MH4EtTxlwRFmXjxTdOSsj47lkVjKUzxE86tFrK2roynlBHOs6ysbS/+A2 ylwb3tohBYisncO5axNjedPuDCtM+MCM5Wq4S1M7LZQCkjWnDKrQHn9ptJNS+IFxd6Aau 0J5OscSW2GByVdXEbVzVkffFIW5wxwjBH4lvCudMUqZDk/JCD4SomiaMfDelXeR9MGQ== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=T6LOEh56; 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 6718D606A31C for ; Thu, 12 Nov 2026 21:57:49 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=T6LOEh56 Received: by smtp.kernel.org (Postfix) with ESMTPSA id 583A41F000C4; Thu, 12 Nov 2026 21:57:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794520668; bh=YIcAatM9lLgopjMYOpAidm6KFqZNJ7St4aXap4jyYYI=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=T6LOEh56YVH834FEfLKaO5TVzqoenYRpdAbNtDgt8cQQDiTQTpDZr0skuRuF/gh1Z uqaDgDyBJUSFZ+0OHlt1dIEHgSNqPTpb1O8zo/8Ep2R6OK8DZqRuV51Du7u1JJg5J7 tK6vutLrUqfOp+uQMHTy6fVhdCJ7Ct31cyGDI6I2YAcCYux7n7dQRjrzurqJwb5UMK WaUki+78/VSYFvd3cLTn7vqNIhRMBs5mOZAILOeOhnxx9m3S67myFhUVr3xtLFZi0u /SMU6e4uwjdEK3pv/2LK3aRunEFGWPegfAWKUJMpIXbXHKM0L2bJ0jR0UZaGa1Bz9y IuKp0ig9ZEnbQ== From: Sasha Levin To: stable@vger.kernel.org Cc: Kyle Zeng , "Matthieu Baerts (NGI0)" , Paolo Abeni , Sasha Levin Subject: [PATCH 5.15.y] mptcp: pm: kernel: use RCU to free endpoint listeners Date: Thu, 12 Nov 2026 16:57:46 -0500 Message-ID: <20261112215659.3919615-1-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20261109202450-failed-5.15-49b09ae0bf57@kernel.org> References: <20261109202450-failed-5.15-49b09ae0bf57@kernel.org> X-Mailing-List: stable@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Kyle Zeng [ Upstream commit 49b09ae0bf57b4230187d4cdd0a370558e44a6e8 ] mptcp_pm_nl_create_listen_socket() starts the TCP listener directly instead of going through mptcp_listen(). It consequently misses setting SOCK_RCU_FREE on the parent MPTCP socket. tcp_child_process() can invoke the listener's subflow_data_ready() callback without holding the MPTCP parent lock or a reference to the parent. An authenticated MP_JOIN racing with endpoint teardown can therefore access the parent after its last reference has been dropped. The ADD_ADDR error path can also close an already published listener. Set SOCK_RCU_FREE before __inet_listen_sk() publishes the TCP listener, matching mptcp_listen(). This protects the parent on every subsequent close path, including a failed endpoint addition. Fixes: 1729cf186d8a ("mptcp: create the listening socket for new port") Cc: stable@vger.kernel.org Signed-off-by: Kyle Zeng Reviewed-by: Matthieu Baerts (NGI0) Link: https://patch.msgid.link/20261030042255.74216-1-kylebot@openai.com Signed-off-by: Paolo Abeni [ sashal: adjusted context to insert the flag before kernel_listen() instead of __inet_listen_sk() ] Signed-off-by: Sasha Levin --- net/mptcp/pm_netlink.c | 1 + 1 file changed, 1 insertion(+) diff --git a/net/mptcp/pm_netlink.c b/net/mptcp/pm_netlink.c index e912615e008f3..b748558fd27eb 100644 --- a/net/mptcp/pm_netlink.c +++ b/net/mptcp/pm_netlink.c @@ -1111,6 +1111,7 @@ static int mptcp_pm_nl_create_listen_socket(struct sock *sk, goto out; } + sock_set_flag(newsk, SOCK_RCU_FREE); WRITE_ONCE(mptcp_subflow_ctx(ssock->sk)->pm_listener, true); err = kernel_listen(ssock, backlog); if (err) { -- 2.53.0