diff options
| author | Paolo Abeni <pabeni@redhat.com> | 2020-06-29 22:26:25 +0200 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2020-06-29 17:29:38 -0700 |
| commit | 8a05661b2b266b6dc45af255b3037b00ef31d85d (patch) | |
| tree | d718dfc00e260081387271c1911143a6e4dda717 /net | |
| parent | 76660afbb7a1ac6bef0be34c4c6e76d7e07b74d7 (diff) | |
| download | linux-8a05661b2b266b6dc45af255b3037b00ef31d85d.tar.bz2 | |
mptcp: close poll() races
mptcp_poll always return POLLOUT for unblocking
connect(), ensure that the socket is a suitable
state.
The MPTCP_DATA_READY bit is never cleared on accept:
ensure we don't leave mptcp_accept() with an empty
accept queue and such bit set.
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Davide Caratti <dcaratti@redhat.com>
Reviewed-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
| -rw-r--r-- | net/mptcp/protocol.c | 25 |
1 files changed, 20 insertions, 5 deletions
diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c index f2b2bd37e371..28ec26d97f96 100644 --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -1841,6 +1841,7 @@ static int mptcp_stream_accept(struct socket *sock, struct socket *newsock, if (!ssock) goto unlock_fail; + clear_bit(MPTCP_DATA_READY, &msk->flags); sock_hold(ssock->sk); release_sock(sock->sk); @@ -1861,6 +1862,8 @@ static int mptcp_stream_accept(struct socket *sock, struct socket *newsock, } } + if (inet_csk_listen_poll(ssock->sk)) + set_bit(MPTCP_DATA_READY, &msk->flags); sock_put(ssock->sk); return err; @@ -1869,21 +1872,33 @@ unlock_fail: return -EINVAL; } +static __poll_t mptcp_check_readable(struct mptcp_sock *msk) +{ + return test_bit(MPTCP_DATA_READY, &msk->flags) ? EPOLLIN | EPOLLRDNORM : + 0; +} + static __poll_t mptcp_poll(struct file *file, struct socket *sock, struct poll_table_struct *wait) { struct sock *sk = sock->sk; struct mptcp_sock *msk; __poll_t mask = 0; + int state; msk = mptcp_sk(sk); sock_poll_wait(file, sock, wait); - if (test_bit(MPTCP_DATA_READY, &msk->flags)) - mask = EPOLLIN | EPOLLRDNORM; - if (sk_stream_is_writeable(sk) && - test_bit(MPTCP_SEND_SPACE, &msk->flags)) - mask |= EPOLLOUT | EPOLLWRNORM; + state = inet_sk_state_load(sk); + if (state == TCP_LISTEN) + return mptcp_check_readable(msk); + + if (state != TCP_SYN_SENT && state != TCP_SYN_RECV) { + mask |= mptcp_check_readable(msk); + if (sk_stream_is_writeable(sk) && + test_bit(MPTCP_SEND_SPACE, &msk->flags)) + mask |= EPOLLOUT | EPOLLWRNORM; + } if (sk->sk_shutdown & RCV_SHUTDOWN) mask |= EPOLLIN | EPOLLRDNORM | EPOLLRDHUP; |