| From 0ad529d9fd2bfa3fc619552a8d2fb2f2ef0bce2e Mon Sep 17 00:00:00 2001 |
| From: Paolo Abeni <pabeni@redhat.com> |
| Date: Tue, 20 Jun 2023 18:24:19 +0200 |
| Subject: mptcp: fix possible divide by zero in recvmsg() |
| |
| From: Paolo Abeni <pabeni@redhat.com> |
| |
| commit 0ad529d9fd2bfa3fc619552a8d2fb2f2ef0bce2e upstream. |
| |
| Christoph reported a divide by zero bug in mptcp_recvmsg(): |
| |
| divide error: 0000 [#1] PREEMPT SMP |
| CPU: 1 PID: 19978 Comm: syz-executor.6 Not tainted 6.4.0-rc2-gffcc7899081b #20 |
| Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.11.0-2.el7 04/01/2014 |
| RIP: 0010:__tcp_select_window+0x30e/0x420 net/ipv4/tcp_output.c:3018 |
| Code: 11 ff 0f b7 cd c1 e9 0c b8 ff ff ff ff d3 e0 89 c1 f7 d1 01 cb 21 c3 eb 17 e8 2e 83 11 ff 31 db eb 0e e8 25 83 11 ff 89 d8 99 <f7> 7c 24 04 29 d3 65 48 8b 04 25 28 00 00 00 48 3b 44 24 10 75 60 |
| RSP: 0018:ffffc90000a07a18 EFLAGS: 00010246 |
| RAX: 000000000000ffd7 RBX: 000000000000ffd7 RCX: 0000000000040000 |
| RDX: 0000000000000000 RSI: 000000000003ffff RDI: 0000000000040000 |
| RBP: 000000000000ffd7 R08: ffffffff820cf297 R09: 0000000000000001 |
| R10: 0000000000000000 R11: ffffffff8103d1a0 R12: 0000000000003f00 |
| R13: 0000000000300000 R14: ffff888101cf3540 R15: 0000000000180000 |
| FS: 00007f9af4c09640(0000) GS:ffff88813bd00000(0000) knlGS:0000000000000000 |
| CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 |
| CR2: 0000001b33824000 CR3: 000000012f241001 CR4: 0000000000170ee0 |
| Call Trace: |
| <TASK> |
| __tcp_cleanup_rbuf+0x138/0x1d0 net/ipv4/tcp.c:1611 |
| mptcp_recvmsg+0xcb8/0xdd0 net/mptcp/protocol.c:2034 |
| inet_recvmsg+0x127/0x1f0 net/ipv4/af_inet.c:861 |
| ____sys_recvmsg+0x269/0x2b0 net/socket.c:1019 |
| ___sys_recvmsg+0xe6/0x260 net/socket.c:2764 |
| do_recvmmsg+0x1a5/0x470 net/socket.c:2858 |
| __do_sys_recvmmsg net/socket.c:2937 [inline] |
| __se_sys_recvmmsg net/socket.c:2953 [inline] |
| __x64_sys_recvmmsg+0xa6/0x130 net/socket.c:2953 |
| do_syscall_x64 arch/x86/entry/common.c:50 [inline] |
| do_syscall_64+0x47/0xa0 arch/x86/entry/common.c:80 |
| entry_SYSCALL_64_after_hwframe+0x72/0xdc |
| RIP: 0033:0x7f9af58fc6a9 |
| Code: 5c c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 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 8b 0d 4f 37 0d 00 f7 d8 64 89 01 48 |
| RSP: 002b:00007f9af4c08cd8 EFLAGS: 00000246 ORIG_RAX: 000000000000012b |
| RAX: ffffffffffffffda RBX: 00000000006bc050 RCX: 00007f9af58fc6a9 |
| RDX: 0000000000000001 RSI: 0000000020000140 RDI: 0000000000000004 |
| RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 |
| R10: 0000000000000f00 R11: 0000000000000246 R12: 00000000006bc05c |
| R13: fffffffffffffea8 R14: 00000000006bc050 R15: 000000000001fe40 |
| </TASK> |
| |
| mptcp_recvmsg is allowed to release the msk socket lock when |
| blocking, and before re-acquiring it another thread could have |
| switched the sock to TCP_LISTEN status - with a prior |
| connect(AF_UNSPEC) - also clearing icsk_ack.rcv_mss. |
| |
| Address the issue preventing the disconnect if some other process is |
| concurrently performing a blocking syscall on the same socket, alike |
| commit 4faeee0cf8a5 ("tcp: deny tcp_disconnect() when threads are waiting"). |
| |
| Fixes: a6b118febbab ("mptcp: add receive buffer auto-tuning") |
| Cc: stable@vger.kernel.org |
| Reported-by: Christoph Paasch <cpaasch@apple.com> |
| Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/404 |
| Signed-off-by: Paolo Abeni <pabeni@redhat.com> |
| Tested-by: Christoph Paasch <cpaasch@apple.com> |
| Reviewed-by: Matthieu Baerts <matthieu.baerts@tessares.net> |
| Signed-off-by: Matthieu Baerts <matthieu.baerts@tessares.net> |
| Signed-off-by: Jakub Kicinski <kuba@kernel.org> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| --- |
| net/mptcp/protocol.c | 7 +++++++ |
| 1 file changed, 7 insertions(+) |
| |
| --- a/net/mptcp/protocol.c |
| +++ b/net/mptcp/protocol.c |
| @@ -3060,6 +3060,12 @@ static int mptcp_disconnect(struct sock |
| { |
| struct mptcp_sock *msk = mptcp_sk(sk); |
| |
| + /* Deny disconnect if other threads are blocked in sk_wait_event() |
| + * or inet_wait_for_connect(). |
| + */ |
| + if (sk->sk_wait_pending) |
| + return -EBUSY; |
| + |
| /* We are on the fastopen error path. We can't call straight into the |
| * subflows cleanup code due to lock nesting (we are already under |
| * msk->firstsocket lock). |
| @@ -3126,6 +3132,7 @@ struct sock *mptcp_sk_clone_init(const s |
| inet_sk(nsk)->pinet6 = mptcp_inet6_sk(nsk); |
| #endif |
| |
| + nsk->sk_wait_pending = 0; |
| __mptcp_init_sock(nsk); |
| |
| msk = mptcp_sk(nsk); |
