commit dbd46ab412b8fb395f2b0ff6f6a7eec9df311550
author Alexander Drozdov <al.drozdov@gmail.com> Tue Jul 28 13:57:01 2015 +0300
committer David S. Miller <davem@davemloft.net> Wed Jul 29 00:09:58 2015 -0700
tree 119701e15a3be300e89a3cfd2860e51f16ea86ad
parent 11c91ef98f37cd743098de26160fffd7f9bd40e1

packet: tpacket_snd(): fix signed/unsigned comparison

tpacket_fill_skb() can return a negative value (-errno) which
is stored in tp_len variable. In that case the following
condition will be (but shouldn't be) true:

tp_len > dev->mtu + dev->hard_header_len

as dev->mtu and dev->hard_header_len are both unsigned.

That may lead to just returning an incorrect EMSGSIZE errno
to the user.

Fixes: 52f1454f629fa ("packet: allow to transmit +4 byte in TX_RING slot for VLAN case")
Signed-off-by: Alexander Drozdov <al.drozdov@gmail.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>