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| author | Alexander Drozdov <al.drozdov@gmail.com> | 2015-07-28 13:57:01 +0300 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2015-07-29 00:09:58 -0700 |
| commit | dbd46ab412b8fb395f2b0ff6f6a7eec9df311550 (patch) | |
| tree | 119701e15a3be300e89a3cfd2860e51f16ea86ad /net/packet/af_packet.c | |
| parent | 11c91ef98f37cd743098de26160fffd7f9bd40e1 (diff) | |
| download | lwn-dbd46ab412b8fb395f2b0ff6f6a7eec9df311550.tar.gz lwn-dbd46ab412b8fb395f2b0ff6f6a7eec9df311550.zip | |
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>
Diffstat (limited to 'net/packet/af_packet.c')
| -rw-r--r-- | net/packet/af_packet.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c index c7c42eb617ef..ed458b315ef4 100644 --- a/net/packet/af_packet.c +++ b/net/packet/af_packet.c @@ -2403,7 +2403,8 @@ static int tpacket_snd(struct packet_sock *po, struct msghdr *msg) } tp_len = tpacket_fill_skb(po, skb, ph, dev, size_max, proto, addr, hlen); - if (tp_len > dev->mtu + dev->hard_header_len) { + if (likely(tp_len >= 0) && + tp_len > dev->mtu + dev->hard_header_len) { struct ethhdr *ehdr; /* Earlier code assumed this would be a VLAN pkt, * double-check this now that we have the actual |