| From | Ben Hutchings <> | Date | Mon, 21 Oct 2013 09:46:28 +0100 | Subject | [PATCH 3.2 008/149] tun: signedness bug in tun_get_user() |
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3.2.52-rc1 review patch. If anyone has any objections, please let me know.
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From: Dan Carpenter <dan.carpenter@oracle.com>
[ 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: Ben Hutchings <ben@decadent.org.uk> --- drivers/net/tun.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/drivers/net/tun.c b/drivers/net/tun.c index f4c5de6..ee1aab0 100644 --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -614,8 +614,9 @@ static ssize_t tun_get_user(struct tun_struct *tun, 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; @@ -623,8 +624,9 @@ static ssize_t tun_get_user(struct tun_struct *tun, } 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;
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