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 EE95563B8 for ; Mon, 20 Feb 2023 13:57:24 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 75283C433EF; Mon, 20 Feb 2023 13:57:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1676901444; bh=UKI7qk1JBJixYFVxGWD0KILYZS8i/mygS2GNMpIlC+k=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=RDIPqBGdzbtvQ7DKGHsBfvfrdSgcXm3QlkW8aooCjBwpsUG7aXAemM/RdcCUFe0Am ruAUBe5/ahLfZUnXDaoGxDiBU8M9Q3lhYGswWD6SZ2dRwyDJkj6Mg5U3DpGGRQMhrG C/lh2MlBa67jaX0mw3IJdMb/ranGGfaPM8GF2HT0= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Paolo Abeni , Matthieu Baerts , "David S. Miller" , Sasha Levin Subject: [PATCH 6.1 002/118] mptcp: fix locking for setsockopt corner-case Date: Mon, 20 Feb 2023 14:35:18 +0100 Message-Id: <20230220133600.497450353@linuxfoundation.org> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230220133600.368809650@linuxfoundation.org> References: <20230220133600.368809650@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Paolo Abeni [ Upstream commit 21e43569685de4ad773fb060c11a15f3fd5e7ac4 ] We need to call the __mptcp_nmpc_socket(), and later subflow socket access under the msk socket lock, or e.g. a racing connect() could change the socket status under the hood, with unexpected results. Fixes: 54635bd04701 ("mptcp: add TCP_FASTOPEN_CONNECT socket option") Cc: stable@vger.kernel.org Signed-off-by: Paolo Abeni Reviewed-by: Matthieu Baerts Signed-off-by: Matthieu Baerts Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- net/mptcp/sockopt.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/net/mptcp/sockopt.c b/net/mptcp/sockopt.c index 8d3b09d75c3ae..696ba398d699a 100644 --- a/net/mptcp/sockopt.c +++ b/net/mptcp/sockopt.c @@ -772,14 +772,21 @@ static int mptcp_setsockopt_sol_tcp_defer(struct mptcp_sock *msk, sockptr_t optv static int mptcp_setsockopt_first_sf_only(struct mptcp_sock *msk, int level, int optname, sockptr_t optval, unsigned int optlen) { + struct sock *sk = (struct sock *)msk; struct socket *sock; + int ret = -EINVAL; /* Limit to first subflow, before the connection establishment */ + lock_sock(sk); sock = __mptcp_nmpc_socket(msk); if (!sock) - return -EINVAL; + goto unlock; - return tcp_setsockopt(sock->sk, level, optname, optval, optlen); + ret = tcp_setsockopt(sock->sk, level, optname, optval, optlen); + +unlock: + release_sock(sk); + return ret; } static int mptcp_setsockopt_sol_tcp(struct mptcp_sock *msk, int optname, -- 2.39.0