diff options
| author | Alexander Popov <alex.popov@linux.com> | 2021-02-01 11:47:19 +0300 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2021-02-01 19:54:30 -0800 |
| commit | c518adafa39f37858697ac9309c6cf1805581446 (patch) | |
| tree | 3210f168d0994023031222b8cce28bc546e3137a /net | |
| parent | 938e0fcd3253efdef8924714158911286d08cfe1 (diff) | |
| download | linux-c518adafa39f37858697ac9309c6cf1805581446.tar.bz2 | |
vsock: fix the race conditions in multi-transport support
There are multiple similar bugs implicitly introduced by the
commit c0cfa2d8a788fcf4 ("vsock: add multi-transports support") and
commit 6a2c0962105ae8ce ("vsock: prevent transport modules unloading").
The bug pattern:
[1] vsock_sock.transport pointer is copied to a local variable,
[2] lock_sock() is called,
[3] the local variable is used.
VSOCK multi-transport support introduced the race condition:
vsock_sock.transport value may change between [1] and [2].
Let's copy vsock_sock.transport pointer to local variables after
the lock_sock() call.
Fixes: c0cfa2d8a788fcf4 ("vsock: add multi-transports support")
Signed-off-by: Alexander Popov <alex.popov@linux.com>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Reviewed-by: Jorgen Hansen <jhansen@vmware.com>
Link: https://lore.kernel.org/r/20210201084719.2257066-1-alex.popov@linux.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net')
| -rw-r--r-- | net/vmw_vsock/af_vsock.c | 17 |
1 files changed, 12 insertions, 5 deletions
diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c index b12d3a322242..6894f21dc147 100644 --- a/net/vmw_vsock/af_vsock.c +++ b/net/vmw_vsock/af_vsock.c @@ -1014,9 +1014,12 @@ static __poll_t vsock_poll(struct file *file, struct socket *sock, mask |= EPOLLOUT | EPOLLWRNORM | EPOLLWRBAND; } else if (sock->type == SOCK_STREAM) { - const struct vsock_transport *transport = vsk->transport; + const struct vsock_transport *transport; + lock_sock(sk); + transport = vsk->transport; + /* Listening sockets that have connections in their accept * queue can be read. */ @@ -1099,10 +1102,11 @@ static int vsock_dgram_sendmsg(struct socket *sock, struct msghdr *msg, err = 0; sk = sock->sk; vsk = vsock_sk(sk); - transport = vsk->transport; lock_sock(sk); + transport = vsk->transport; + err = vsock_auto_bind(vsk); if (err) goto out; @@ -1561,10 +1565,11 @@ static int vsock_stream_setsockopt(struct socket *sock, err = 0; sk = sock->sk; vsk = vsock_sk(sk); - transport = vsk->transport; lock_sock(sk); + transport = vsk->transport; + switch (optname) { case SO_VM_SOCKETS_BUFFER_SIZE: COPY_IN(val); @@ -1697,7 +1702,6 @@ static int vsock_stream_sendmsg(struct socket *sock, struct msghdr *msg, sk = sock->sk; vsk = vsock_sk(sk); - transport = vsk->transport; total_written = 0; err = 0; @@ -1706,6 +1710,8 @@ static int vsock_stream_sendmsg(struct socket *sock, struct msghdr *msg, lock_sock(sk); + transport = vsk->transport; + /* Callers should not provide a destination with stream sockets. */ if (msg->msg_namelen) { err = sk->sk_state == TCP_ESTABLISHED ? -EISCONN : -EOPNOTSUPP; @@ -1840,11 +1846,12 @@ vsock_stream_recvmsg(struct socket *sock, struct msghdr *msg, size_t len, sk = sock->sk; vsk = vsock_sk(sk); - transport = vsk->transport; err = 0; lock_sock(sk); + transport = vsk->transport; + if (!transport || sk->sk_state != TCP_ESTABLISHED) { /* Recvmsg is supposed to return 0 if a peer performs an * orderly shutdown. Differentiate between that case and when a |