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 8FEF781751; Wed, 7 Aug 2024 15:11:56 +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=1723043516; cv=none; b=F9DbDbLLweDuLoGjC3EIDEmKKl0eMcHKi5T1m8TNW78EUT+nkDK4dcmuWhUnqLz8jMWOEH1md+mNAZ7/sXorYiPb+AwNuNf/3q/z2josukYBrWOd6CoRLxo5a6Kx+pHhGgPS2h1d/aSqfsH4Uxjl6ds0MoOKUAl5HaKnEJdkyOc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723043516; c=relaxed/simple; bh=cEWZEMKdC+tbpPlRnq/TsyEr0gvxDo+HrfshmYM34hI=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=esjspgWBTLsoUivw7qfCYlXY0ip+jvOhTx9UX/D6FIloQ4EXUiOS+Mi3u+zCVujZ+g5kNt79JSX/1n2XePPFDkClWj2TAxSC1KVWRm8yY7RvgyrvY7vB5DRKhSzcd2WYCrAy4LQjcLtHAkSyy9dKWMfRvwIRqMSN9B+7/6dBd7Q= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=XsxB9rCe; 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="XsxB9rCe" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 22A8FC32781; Wed, 7 Aug 2024 15:11:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1723043516; bh=cEWZEMKdC+tbpPlRnq/TsyEr0gvxDo+HrfshmYM34hI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=XsxB9rCew8oS+V3j+dYG7/iPBAuuWMGZGxw1TZggwA9Db0eQDVlV/gJ5VLeiBd4Fr pcvBdYA0VNVIO9JgC57fY6iTkYXbhRNtNPHNdQ1vEAmbBcQGs2kdKWym1y3HR2SODh AjnDco56VwpJxpd3/e2Ma7+hVODW5M6O0MvVvnlU= 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 6.6 121/121] mptcp: prevent BPF accessing lowat from a subflow socket. Date: Wed, 7 Aug 2024 17:00:53 +0200 Message-ID: <20240807150023.359740508@linuxfoundation.org> X-Mailer: git-send-email 2.46.0 In-Reply-To: <20240807150019.412911622@linuxfoundation.org> References: <20240807150019.412911622@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.6-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 @@ -1538,6 +1538,10 @@ 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