From nobody Thu Dec 26 13:13:09 2024 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (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 7185B1E3DF4 for ; Fri, 8 Nov 2024 10:59:00 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.133.124 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1731063543; cv=none; b=ZIOtD1G5UTCrgaJgNMVmJur3OpK3EVLIKUzy/8PPA5r8KL5wAcP/x7AYTupZwLGpPI72fWBER33+tWE1W4vMmqZ6DutALXvj57gQrYqfdECuCw2Ym4BDGIvl7J9Qha38/bYcn0Ettue9DzoXGXFzU4+m+Ei75zmG3ZtULHmq5hw= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1731063543; c=relaxed/simple; bh=6VS9VnfuAk+K1Eyqmm/TKciO4GfKZaTxogfw7UAMIbo=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=a7Fw+IMiq+RjDvXz8iYlgcAAGl0YFGTQNNU7nIMg9L3RyQX1oTLg4yE00pWKNkZiz6nYipQTe0GZq5mIwab/qz6A7Ag/+fZ/4LXN0mrEKnz3Znwzb4Gcwm7Hpl1SQsR76cwtRIHWioQm+ThC2AKXJCUMadZUPpmgxt9DzCFgXoQ= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=hVJNzxv1; arc=none smtp.client-ip=170.10.133.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="hVJNzxv1" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1731063539; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=2+LpEpuygvE4o5DXZ4E6E2ItXbhagPjPDPiUxWLNwM4=; b=hVJNzxv1WMnLEnHo8d+A30pSC9iTcW/NIsd1QSQwCoqDPTA6esrmTRTNXtLxzQRefjty2P xBrRmm2/qFkD92yyxEvHCt9Me8A7ZeIJuJumFu0YuwgoBtAqL3UHBXnrddLHlDolqgX7ij gMt/ly+iMSokss/aZKWzPzGDMYSN1KM= Received: from mx-prod-mc-03.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-156-SJ_edObnN1mfNy-JatN0xw-1; Fri, 08 Nov 2024 05:58:53 -0500 X-MC-Unique: SJ_edObnN1mfNy-JatN0xw-1 X-Mimecast-MFC-AGG-ID: SJ_edObnN1mfNy-JatN0xw Received: from mx-prod-int-04.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-04.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.40]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id A4F931955EAC; Fri, 8 Nov 2024 10:58:51 +0000 (UTC) Received: from gerbillo.redhat.com (unknown [10.39.193.90]) by mx-prod-int-04.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id A9BD61956054; Fri, 8 Nov 2024 10:58:48 +0000 (UTC) From: Paolo Abeni To: netdev@vger.kernel.org Cc: Matthieu Baerts , Mat Martineau , Geliang Tang , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Simon Horman , mptcp@lists.linux.dev Subject: [PATCH net 1/2] mptcp: error out earlier on disconnect Date: Fri, 8 Nov 2024 11:58:16 +0100 Message-ID: <8c82ecf71662ecbc47bf390f9905de70884c9f2d.1731060874.git.pabeni@redhat.com> In-Reply-To: References: Precedence: bulk X-Mailing-List: mptcp@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 3.0 on 10.30.177.40 Content-Type: text/plain; charset="utf-8" Eric reported a division by zero splat in the MPTCP protocol: Oops: divide error: 0000 [#1] PREEMPT SMP KASAN PTI CPU: 1 UID: 0 PID: 6094 Comm: syz-executor317 Not tainted 6.12.0-rc5-syzkaller-00291-g05b92660cdfe #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 RIP: 0010:__tcp_select_window+0x5b4/0x1310 net/ipv4/tcp_output.c:3163 Code: f6 44 01 e3 89 df e8 9b 75 09 f8 44 39 f3 0f 8d 11 ff ff ff e8 0d 74 09 f8 45 89 f4 e9 04 ff ff ff e8 00 74 09 f8 44 89 f0 99 7c 24 14 41 29 d6 45 89 f4 e9 ec fe ff ff e8 e8 73 09 f8 48 89 RSP: 0018:ffffc900041f7930 EFLAGS: 00010293 RAX: 0000000000017e67 RBX: 0000000000017e67 RCX: ffffffff8983314b RDX: 0000000000000000 RSI: ffffffff898331b0 RDI: 0000000000000004 RBP: 00000000005d6000 R08: 0000000000000004 R09: 0000000000017e67 R10: 0000000000003e80 R11: 0000000000000000 R12: 0000000000003e80 R13: ffff888031d9b440 R14: 0000000000017e67 R15: 00000000002eb000 FS: 00007feb5d7f16c0(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007feb5d8adbb8 CR3: 0000000074e4c000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __tcp_cleanup_rbuf+0x3e7/0x4b0 net/ipv4/tcp.c:1493 mptcp_rcv_space_adjust net/mptcp/protocol.c:2085 [inline] mptcp_recvmsg+0x2156/0x2600 net/mptcp/protocol.c:2289 inet_recvmsg+0x469/0x6a0 net/ipv4/af_inet.c:885 sock_recvmsg_nosec net/socket.c:1051 [inline] sock_recvmsg+0x1b2/0x250 net/socket.c:1073 __sys_recvfrom+0x1a5/0x2e0 net/socket.c:2265 __do_sys_recvfrom net/socket.c:2283 [inline] __se_sys_recvfrom net/socket.c:2279 [inline] __x64_sys_recvfrom+0xe0/0x1c0 net/socket.c:2279 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7feb5d857559 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 51 18 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007feb5d7f1208 EFLAGS: 00000246 ORIG_RAX: 000000000000002d RAX: ffffffffffffffda RBX: 00007feb5d8e1318 RCX: 00007feb5d857559 RDX: 000000800000000e RSI: 0000000000000000 RDI: 0000000000000003 RBP: 00007feb5d8e1310 R08: 0000000000000000 R09: ffffffff81000000 R10: 0000000000000100 R11: 0000000000000246 R12: 00007feb5d8e131c R13: 00007feb5d8ae074 R14: 000000800000000e R15: 00000000fffffdef and provided a nice reproducer. The root cause is the current bad handling of racing disconnect. After the blamed commit below, sk_wait_data() can return (with error) with the underlying socket disconnected and a zero rcv_mss. Catch the error and return without performing any additional operations on the current socket. Reported-by: Eric Dumazet Fixes: 419ce133ab92 ("tcp: allow again tcp_disconnect() when threads are wa= iting") Signed-off-by: Paolo Abeni Reviewed-by: Matthieu Baerts (NGI0) --- net/mptcp/protocol.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-) diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c index d263091659e0..95a5a3da3944 100644 --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -2205,7 +2205,7 @@ static int mptcp_recvmsg(struct sock *sk, struct msgh= dr *msg, size_t len, cmsg_flags =3D MPTCP_CMSG_INQ; =20 while (copied < len) { - int bytes_read; + int err, bytes_read; =20 bytes_read =3D __mptcp_recvmsg_mskq(msk, msg, len - copied, flags, &tss,= &cmsg_flags); if (unlikely(bytes_read < 0)) { @@ -2267,9 +2267,16 @@ static int mptcp_recvmsg(struct sock *sk, struct msg= hdr *msg, size_t len, } =20 pr_debug("block timeout %ld\n", timeo); - sk_wait_data(sk, &timeo, NULL); + mptcp_rcv_space_adjust(msk, copied); + err =3D sk_wait_data(sk, &timeo, NULL); + if (err < 0) { + err =3D copied ? : err; + goto out_err; + } } =20 + mptcp_rcv_space_adjust(msk, copied); + out_err: if (cmsg_flags && copied >=3D 0) { if (cmsg_flags & MPTCP_CMSG_TS) @@ -2285,8 +2292,6 @@ static int mptcp_recvmsg(struct sock *sk, struct msgh= dr *msg, size_t len, pr_debug("msk=3D%p rx queue empty=3D%d:%d copied=3D%d\n", msk, skb_queue_empty_lockless(&sk->sk_receive_queue), skb_queue_empty(&msk->receive_queue), copied); - if (!(flags & MSG_PEEK)) - mptcp_rcv_space_adjust(msk, copied); =20 release_sock(sk); return copied; --=20 2.45.2 From nobody Thu Dec 26 13:13:09 2024 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (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 415CD1E3DF9 for ; Fri, 8 Nov 2024 10:59:00 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1731063542; cv=none; b=h8YhRX5cLFbK+ZdVr6arrjbrCprGcjdiMpxoPPiKzqxyHePXamy3gJbvakSmX2jv4b8/uWee56DIhx4v5J8GIEdVpW1+aBfl2eotlgImkyRRw5QsG8AQF+KL7J3SwJB7cXtzCamuKcr6kLT5bD+6jPp1FRsJvDlACnIVNDp4Dnc= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1731063542; c=relaxed/simple; bh=HnlIv0shPYlrmFHUiRovfXGGOpfl3wKy7+j8e+K5FkI=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=qlvPPycYYBSn6DbOWLNtiutRrpRGPDmxDu6SbZ37zjnXO6/TzjpXZfn4O1C/t4SJPx6icq1Mx390myirOXOfqZhDzSA3//OYKVRop2WgRTe76hq8BflpNbXunriVTWF8vN/pM4/c2yIZRc+An9UqfRO8Pbwqoxi88yJ3QvlMpns= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=TNPHwcZ2; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="TNPHwcZ2" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1731063540; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=iR/x+dH77F1MdZ4GlNiB8vuIlGOSlBv4jBLCMBeFDpU=; b=TNPHwcZ2HHeq6jH1E5W0gMRQGCXDDSex7iPt1PI/DvtQ7zn1fMZ/ayUXk5huGo+molVEtn 4vXKcnaVZZQyJNvbPvbgNsB06a7zCSmcqkKjSE1W6G2/MRf6RoB3y0u2YSRhVhbnlL0POH BB0duBZ2Nt7SvUlziewe5B3AAlnz4+0= Received: from mx-prod-mc-02.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-499-8HrvlfFJOmyBmB4juogIgw-1; Fri, 08 Nov 2024 05:58:56 -0500 X-MC-Unique: 8HrvlfFJOmyBmB4juogIgw-1 X-Mimecast-MFC-AGG-ID: 8HrvlfFJOmyBmB4juogIgw Received: from mx-prod-int-04.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-04.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.40]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-02.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 1DFD21944DF3; Fri, 8 Nov 2024 10:58:55 +0000 (UTC) Received: from gerbillo.redhat.com (unknown [10.39.193.90]) by mx-prod-int-04.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 2B9641956054; Fri, 8 Nov 2024 10:58:51 +0000 (UTC) From: Paolo Abeni To: netdev@vger.kernel.org Cc: Matthieu Baerts , Mat Martineau , Geliang Tang , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Simon Horman , mptcp@lists.linux.dev Subject: [PATCH net 2/2] mptcp: cope racing subflow creation in mptcp_rcv_space_adjust Date: Fri, 8 Nov 2024 11:58:17 +0100 Message-ID: <02374660836e1b52afc91966b7535c8c5f7bafb0.1731060874.git.pabeni@redhat.com> In-Reply-To: References: Precedence: bulk X-Mailing-List: mptcp@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 3.0 on 10.30.177.40 Content-Type: text/plain; charset="utf-8" Additional active subflows - i.e. created by the in kernel path manager - are included into the subflow list before starting the 3whs. A racing recvmsg() spooling data received on an already established subflow would unconditionally call tcp_cleanup_rbuf() on all the current subflows, potentially hitting a divide by zero error on the newly created ones. Explicitly check that the subflow is in a suitable state before invoking tcp_cleanup_rbuf(). Fixes: c76c6956566f ("mptcp: call tcp_cleanup_rbuf on subflows") Signed-off-by: Paolo Abeni Reviewed-by: Matthieu Baerts (NGI0) --- net/mptcp/protocol.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c index 95a5a3da3944..48d480982b78 100644 --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -2082,7 +2082,8 @@ static void mptcp_rcv_space_adjust(struct mptcp_sock = *msk, int copied) slow =3D lock_sock_fast(ssk); WRITE_ONCE(ssk->sk_rcvbuf, rcvbuf); WRITE_ONCE(tcp_sk(ssk)->window_clamp, window_clamp); - tcp_cleanup_rbuf(ssk, 1); + if (tcp_can_send_ack(ssk)) + tcp_cleanup_rbuf(ssk, 1); unlock_sock_fast(ssk, slow); } } --=20 2.45.2