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 9396381AC1; Mon, 8 Apr 2024 13:24:24 +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=1712582664; cv=none; b=jzEEBtLOEgZKA3uF1IRIoVUiiDR2a7cyT7C2DkjbLKmw4GrIqwL9njsAW6VzIqRm6l0dBN6Dbnu3+TQM4anmv8SSwtpv1pIco8hlq/iQLaUK5QEnrQbFh4JL6OnNxIm/28St7UWdaw4bi3ejuffv9fiUmjUDdFC+6Dk2DU05agk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712582664; c=relaxed/simple; bh=SKd3VH/u8CmEqyypMLdf3FftggQGYyZIPKZEWBbfdYY=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=tAGHkj/3ZIQgO3Ta2WYZgViRoDhquRGaF3L8TdfNjDYOHbtUcLmevBOuo9HuQ5rWkAoSrmpt0zu5MAsJ7FOu34i46rKKsniF03PfoOuPYFXVpq/8NCKl04JK06XU9ZA7Mmv0tbFXIkmF9aHxYhjI5Omy44+Iwf01DARNWk7rkXc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=d8TauiRp; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="d8TauiRp" Received: by smtp.kernel.org (Postfix) with ESMTPSA id CC66FC433C7; Mon, 8 Apr 2024 13:24:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1712582664; bh=SKd3VH/u8CmEqyypMLdf3FftggQGYyZIPKZEWBbfdYY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=d8TauiRpJelVCreV4JlQif73mL6xrtyyw81ogBRefOZjgwkCStiAJZzVA504RyXKh +xmEvjNeLfnOYvp8PftAGMi5g35jXr5Gj/+Qqf4kLnOMgkh5/uiPW5Bf5G8TzwOx6c TveqHziYuPG2E1du7NApEIISsop55TMJv0AaFR2g= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Alexei Starovoitov , Paolo Abeni , Mat Martineau , "Matthieu Baerts (NGI0)" , Jakub Kicinski Subject: [PATCH 6.8 094/273] mptcp: prevent BPF accessing lowat from a subflow socket. Date: Mon, 8 Apr 2024 14:56:09 +0200 Message-ID: <20240408125312.219734618@linuxfoundation.org> X-Mailer: git-send-email 2.44.0 In-Reply-To: <20240408125309.280181634@linuxfoundation.org> References: <20240408125309.280181634@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.8-stable review patch. If anyone has any objections, please let me know. ------------------ From: Paolo Abeni commit fcf4692fa39e86a590c14a4af2de704e1d20a3b5 upstream. Alexei reported the following splat: WARNING: CPU: 32 PID: 3276 at net/mptcp/subflow.c:1430 subflow_data_ready+0x147/0x1c0 Modules linked in: dummy bpf_testmod(O) [last unloaded: bpf_test_no_cfi(O)] CPU: 32 PID: 3276 Comm: test_progs Tainted: GO 6.8.0-12873-g2c43c33bfd23 Call Trace: mptcp_set_rcvlowat+0x79/0x1d0 sk_setsockopt+0x6c0/0x1540 __bpf_setsockopt+0x6f/0x90 bpf_sock_ops_setsockopt+0x3c/0x90 bpf_prog_509ce5db2c7f9981_bpf_test_sockopt_int+0xb4/0x11b bpf_prog_dce07e362d941d2b_bpf_test_socket_sockopt+0x12b/0x132 bpf_prog_348c9b5faaf10092_skops_sockopt+0x954/0xe86 __cgroup_bpf_run_filter_sock_ops+0xbc/0x250 tcp_connect+0x879/0x1160 tcp_v6_connect+0x50c/0x870 mptcp_connect+0x129/0x280 __inet_stream_connect+0xce/0x370 inet_stream_connect+0x36/0x50 bpf_trampoline_6442491565+0x49/0xef inet_stream_connect+0x5/0x50 __sys_connect+0x63/0x90 __x64_sys_connect+0x14/0x20 The root cause of the issue is that bpf allows accessing mptcp-level proto_ops from a tcp subflow scope. Fix the issue detecting the problematic call and preventing any action. Reported-by: Alexei Starovoitov Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/482 Fixes: 5684ab1a0eff ("mptcp: give rcvlowat some love") Signed-off-by: Paolo Abeni Reviewed-by: Mat Martineau Reviewed-by: Matthieu Baerts (NGI0) Link: https://lore.kernel.org/r/d8cb7d8476d66cb0812a6e29cd1e626869d9d53e.1711738080.git.pabeni@redhat.com Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman --- net/mptcp/sockopt.c | 4 ++++ 1 file changed, 4 insertions(+) --- a/net/mptcp/sockopt.c +++ b/net/mptcp/sockopt.c @@ -1500,6 +1500,10 @@ int mptcp_set_rcvlowat(struct sock *sk, struct mptcp_subflow_context *subflow; int space, cap; + /* bpf can land here with a wrong sk type */ + if (sk->sk_protocol == IPPROTO_TCP) + return -EINVAL; + if (sk->sk_userlocks & SOCK_RCVBUF_LOCK) cap = sk->sk_rcvbuf >> 1; else