From: Jason Wang <jasowang@redhat.com>
Date: Thu, 21 Jun 2018 05:11:31 +0000 (+0800)
Subject: vhost_net: validate sock before trying to put its fd
X-Git-Tag: v4.18-rc3~40^2~15
X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=commitdiff_plain;h=b8f1f65882f07913157c44673af7ec0b308d03eb;p=linux.git

vhost_net: validate sock before trying to put its fd

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>
---

diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
index 686dc670fd29..29756d88799b 100644
--- a/drivers/vhost/net.c
+++ b/drivers/vhost/net.c
@@ -1226,7 +1226,8 @@ static long vhost_net_set_backend(struct vhost_net *n, unsigned index, int fd)
 	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);
 err: