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authorDan Carpenter <dan.carpenter@oracle.com>2013-08-15 15:52:57 +0300
committerDavid S. Miller <davem@davemloft.net>2013-08-15 14:51:23 -0700
commit15718ea0d844e4816dbd95d57a8a0e3e264ba90e (patch)
tree1cd9c06a746d5e7173bfbe07ed84058c47ec4736
parentd1fcc172570fa4de69c60bdabe1e1ccfcfe80c26 (diff)
downloadlinux-15718ea0d844e4816dbd95d57a8a0e3e264ba90e.tar.gz
tun: signedness bug in tun_get_user()
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>
-rw-r--r--drivers/net/tun.c6
1 files changed, 4 insertions, 2 deletions
diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index 5a8ee1cf090a..71af122edf2d 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -1074,8 +1074,9 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
u32 rxhash;
if (!(tun->flags & TUN_NO_PI)) {
- if ((len -= sizeof(pi)) < 0)
+ if (len < sizeof(pi))
return -EINVAL;
+ len -= sizeof(pi);
if (memcpy_fromiovecend((void *)&pi, iv, 0, sizeof(pi)))
return -EFAULT;
@@ -1083,8 +1084,9 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
}
if (tun->flags & TUN_VNET_HDR) {
- if ((len -= tun->vnet_hdr_sz) < 0)
+ if (len < tun->vnet_hdr_sz)
return -EINVAL;
+ len -= tun->vnet_hdr_sz;
if (memcpy_fromiovecend((void *)&gso, iv, offset, sizeof(gso)))
return -EFAULT;