tun: signedness bug in tun_get_user()
[ Upstream commit 15718ea0d844e4816dbd95d57a8a0e3e264ba90e ]
The recent fix d9bf5f1309 "tun: compare with 0 instead of total_len" is
not totally correct. Because "len" and "sizeof()" are size_t type, that
means they are never less than zero.
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index 92213b3..d25f929 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -615,8 +615,9 @@
int offset = 0;
if (!(tun->flags & TUN_NO_PI)) {
- if ((len -= sizeof(pi)) > count)
+ if (len < sizeof(pi))
return -EINVAL;
+ len -= sizeof(pi);
if (memcpy_fromiovecend((void *)&pi, iv, 0, sizeof(pi)))
return -EFAULT;
@@ -624,8 +625,9 @@
}
if (tun->flags & TUN_VNET_HDR) {
- if ((len -= tun->vnet_hdr_sz) > count)
+ if (len < tun->vnet_hdr_sz)
return -EINVAL;
+ len -= tun->vnet_hdr_sz;
if (memcpy_fromiovecend((void *)&gso, iv, offset, sizeof(gso)))
return -EFAULT;