tap: free skb if flags error

[ Upstream commit 61d78537843e676e7f56ac6db333db0c0529b892 ]

tap_recvmsg() supports accepting skb by msg_control after
commit 3b4ba04acca8 ("tap: support receiving skb from msg_control"),
the skb if presented should be freed within the function, otherwise
it would be leaked.

Signed-off-by: Wei Xu <wexu@redhat.com>
Reported-by: Matthew Rosato <mjrosato@linux.vnet.ibm.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/net/tap.c b/drivers/net/tap.c
index 6c0c84c33e1fb62f259881de910934470b6a8929..e4c6c78fab3b34efc16a262c6a588f5021cb5a45 100644 (file)
--- a/drivers/net/tap.c
+++ b/drivers/net/tap.c
@@ -829,8 +829,11 @@ static ssize_t tap_do_read(struct tap_queue *q,
        DEFINE_WAIT(wait);
        ssize_t ret = 0;
 
-       if (!iov_iter_count(to))
+       if (!iov_iter_count(to)) {
+               if (skb)
+                       kfree_skb(skb);
                return 0;
+       }
 
        if (skb)
                goto put;
@@ -1154,11 +1157,14 @@ static int tap_recvmsg(struct socket *sock, struct msghdr *m,
                       size_t total_len, int flags)
 {
        struct tap_queue *q = container_of(sock, struct tap_queue, sock);
+       struct sk_buff *skb = m->msg_control;
        int ret;
-       if (flags & ~(MSG_DONTWAIT|MSG_TRUNC))
+       if (flags & ~(MSG_DONTWAIT|MSG_TRUNC)) {
+               if (skb)
+                       kfree_skb(skb);
                return -EINVAL;
-       ret = tap_do_read(q, &m->msg_iter, flags & MSG_DONTWAIT,
-                         m->msg_control);
+       }
+       ret = tap_do_read(q, &m->msg_iter, flags & MSG_DONTWAIT, skb);
        if (ret > total_len) {
                m->msg_flags |= MSG_TRUNC;
                ret = flags & MSG_TRUNC ? ret : total_len;