7.2-stable review patch. If anyone has any objections, please let me know. ------------------ From: Michal Luczaj [ Upstream commit 4f6ac74fa594a918d41255c941256e1d51592d3b ] Handle the TCP_ESTABLISHED -> TCP_CLOSING transition on OP_RST, which can race with the connect loop. Immediately break and return 0 on ESTABLISHED/CLOSING. The return value of connect() should reflect what happened up to the point the connection was established or failed. Events that occur afterwards must not affect it. E.g. even if OP_RW has already set sk_err, connect() should still return 0, not ENOBUFS because of it. Adapt the inaccurate comment above signal_pending(). Resetting a socket that is still present in connected_table can lead to memory corruption. The reporter noted lost transports for in-flight skbs, and I have reproduced crashes caused by re-insertion into connected_table. list_add double add: new=, prev=, next=. kernel BUG at lib/list_debug.c:35! Oops: invalid opcode: 0000 [#1] SMP KASAN NOPTI Workqueue: vsock-loopback vsock_loopback_work RIP: 0010:__list_add_valid_or_report+0x11f/0x130 Call Trace: vsock_insert_connected.cold+0xe/0x13 virtio_transport_recv_pkt+0x10e9/0x1460 vsock_loopback_work+0x305/0x480 process_one_work+0xe4c/0x1560 worker_thread+0x4f1/0xd60 kthread+0x36e/0x470 ret_from_fork+0x47b/0x6b0 ret_from_fork_asm+0x1a/0x30 This fix is supplementary to commit 002541ef650b ("vsock: Ignore signal/timeout on connect() if already established"). Details under Link. Fixes: d021c344051a ("VSOCK: Introduce VM Sockets") Reported-by: Hyunwoo Kim Link: https://lore.kernel.org/netdev/anzT1fREOSyHT99k@v4bel/ Signed-off-by: Michal Luczaj Reviewed-by: Stefano Garzarella Link: https://patch.msgid.link/20261005-vsock-connect-reset-closing-v4-1-15d41cfda3ed@rbox.co Signed-off-by: Paolo Abeni Signed-off-by: Sasha Levin --- net/vmw_vsock/af_vsock.c | 17 ++++++++--------- 1 file changed, 8 insertions(+), 9 deletions(-) diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c index f271a095996c9..db62ee41f1061 100644 --- a/net/vmw_vsock/af_vsock.c +++ b/net/vmw_vsock/af_vsock.c @@ -1809,23 +1809,22 @@ static int vsock_connect(struct socket *sock, struct sockaddr_unsized *addr, timeout = schedule_timeout(timeout); lock_sock(sk); - /* Connection established. Whatever happens to socket once we - * release it, that's not connect()'s concern. No need to go + /* Connection was established. Whatever happens to socket once + * we release it, that's not connect()'s concern. No need to go * into signal and timeout handling. Call it a day. * * Note that allowing to "reset" an already established socket * here is racy and insecure. */ - if (sk->sk_state == TCP_ESTABLISHED) - break; + if (sk->sk_state == TCP_ESTABLISHED || + sk->sk_state == TCP_CLOSING) { + err = 0; + goto out_wait; + } /* If connection was _not_ established and a signal/timeout came * to be, we want the socket's state reset. User space may want - * to retry. - * - * sk_state != TCP_ESTABLISHED implies that socket is not on - * vsock_connected_table. We keep the binding and the transport - * assigned. + * to retry, so we keep the binding and the transport assigned. */ if (signal_pending(current) || timeout == 0) { err = timeout == 0 ? -ETIMEDOUT : sock_intr_errno(timeout); -- 2.53.0