Signal delivery during connect() may result in a disconnect of an already TCP_ESTABLISHED socket. Problem is that such established socket might have been placed in a sockmap before the connection was closed. We end up with a SS_UNCONNECTED vsock in a sockmap. And this, combined with the ability to reassign (unconnected) vsock's transport to NULL, breaks the sockmap contract. As manifested by WARN_ON_ONCE.
connect / state = SS_CONNECTED / sock_map_update_elem if signal_pending state = SS_UNCONNECTED
connect transport = NULL vsock_bpf_recvmsg WARN_ON_ONCE(!vsk->transport)
Ensure the socket does not stay in sockmap.
WARNING: CPU: 8 PID: 1228 at net/vmw_vsock/vsock_bpf.c:97 vsock_bpf_recvmsg+0xb43/0xe00 CPU: 8 UID: 0 PID: 1228 Comm: a.out Not tainted 6.14.0-rc5+ RIP: 0010:vsock_bpf_recvmsg+0xb43/0xe00 sock_recvmsg+0x1b2/0x220 __sys_recvfrom+0x190/0x270 __x64_sys_recvfrom+0xdc/0x1b0 do_syscall_64+0x93/0x1b0 entry_SYSCALL_64_after_hwframe+0x76/0x7e
Fixes: 634f1a7110b4 ("vsock: support sockmap") Reviewed-by: Stefano Garzarella sgarzare@redhat.com Signed-off-by: Michal Luczaj mhal@rbox.co --- net/vmw_vsock/af_vsock.c | 10 +++++++++- net/vmw_vsock/vsock_bpf.c | 1 + 2 files changed, 10 insertions(+), 1 deletion(-)
diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c index 7e3db87ae4333cf63327ec105ca99253569bb9fe..81b1b8e9c946a646778367ab78ca180cef75ef72 100644 --- a/net/vmw_vsock/af_vsock.c +++ b/net/vmw_vsock/af_vsock.c @@ -1579,7 +1579,15 @@ static int vsock_connect(struct socket *sock, struct sockaddr *addr,
if (signal_pending(current)) { err = sock_intr_errno(timeout); - sk->sk_state = sk->sk_state == TCP_ESTABLISHED ? TCP_CLOSING : TCP_CLOSE; + if (sk->sk_state == TCP_ESTABLISHED) { + /* Might have raced with a sockmap update. */ + if (sk->sk_prot->unhash) + sk->sk_prot->unhash(sk); + + sk->sk_state = TCP_CLOSING; + } else { + sk->sk_state = TCP_CLOSE; + } sock->state = SS_UNCONNECTED; vsock_transport_cancel_pkt(vsk); vsock_remove_connected(vsk); diff --git a/net/vmw_vsock/vsock_bpf.c b/net/vmw_vsock/vsock_bpf.c index 07b96d56f3a577af71021b1b8132743554996c4f..c68fdaf09046b68254dac3ea70ffbe73dfa45cef 100644 --- a/net/vmw_vsock/vsock_bpf.c +++ b/net/vmw_vsock/vsock_bpf.c @@ -127,6 +127,7 @@ static void vsock_bpf_rebuild_protos(struct proto *prot, const struct proto *bas { *prot = *base; prot->close = sock_map_close; + prot->unhash = sock_map_unhash; prot->recvmsg = vsock_bpf_recvmsg; prot->sock_is_readable = sk_msg_is_readable; }