[PATCH 3.16 184/366] vhost_net: validate sock before trying to put its fd

Ben Hutchings
2018-11-12T06:04:20Z

From: Jason Wang <jasowang@redhat.com>

commit b8f1f65882f07913157c44673af7ec0b308d03eb upstream.

Sock will be NULL if we pass -1 to vhost_net_set_backend(), but when
we meet errors during ubuf allocation, the code does not check for
NULL before calling sockfd_put(), this will lead NULL
dereferencing. Fixing by checking sock pointer before.

Fixes: bab632d69ee4 ("vhost: vhost TX zero-copy support")
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
drivers/vhost/net.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

--- a/drivers/vhost/net.c
+++ b/drivers/vhost/net.c
@@ -983,7 +983,8 @@ err_used:
if (ubufs)
vhost_net_ubuf_put_wait_and_free(ubufs);
err_ubufs:
- sockfd_put(sock);
+ if (sock)
+ sockfd_put(sock);
err_vq:
mutex_unlock(&vq->mutex);