* [PATCH] packet: tpacket_snd(): fix signed/unsigned comparison
@ 2015-07-28 10:57 Alexander Drozdov
2015-07-28 11:07 ` Daniel Borkmann
2015-07-29 7:10 ` David Miller
0 siblings, 2 replies; 4+ messages in thread
From: Alexander Drozdov @ 2015-07-28 10:57 UTC (permalink / raw)
To: David S. Miller, Daniel Borkmann
Cc: Eric Dumazet, Willem de Bruijn, Al Viro, Eyal Birger,
Michael S. Tsirkin, netdev, linux-kernel, Alexander Drozdov
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.
Signed-off-by: Alexander Drozdov <al.drozdov@gmail.com>
---
net/packet/af_packet.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index c9e8741..d1d3625 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
--
1.9.1
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [PATCH] packet: tpacket_snd(): fix signed/unsigned comparison
2015-07-28 10:57 [PATCH] packet: tpacket_snd(): fix signed/unsigned comparison Alexander Drozdov
@ 2015-07-28 11:07 ` Daniel Borkmann
2015-07-28 11:38 ` Eric Dumazet
2015-07-29 7:10 ` David Miller
1 sibling, 1 reply; 4+ messages in thread
From: Daniel Borkmann @ 2015-07-28 11:07 UTC (permalink / raw)
To: Alexander Drozdov, David S. Miller, Daniel Borkmann
Cc: Eric Dumazet, Willem de Bruijn, Al Viro, Eyal Birger,
Michael S. Tsirkin, netdev, linux-kernel
On 07/28/2015 12:57 PM, Alexander Drozdov wrote:
> 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.
>
> Signed-off-by: Alexander Drozdov <al.drozdov@gmail.com>
Looks good to me, thanks!
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] packet: tpacket_snd(): fix signed/unsigned comparison
2015-07-28 11:07 ` Daniel Borkmann
@ 2015-07-28 11:38 ` Eric Dumazet
0 siblings, 0 replies; 4+ messages in thread
From: Eric Dumazet @ 2015-07-28 11:38 UTC (permalink / raw)
To: Daniel Borkmann
Cc: Alexander Drozdov, David S. Miller, Daniel Borkmann, Eric Dumazet,
Willem de Bruijn, Al Viro, Eyal Birger, Michael S. Tsirkin,
netdev, linux-kernel
On Tue, 2015-07-28 at 13:07 +0200, Daniel Borkmann wrote:
> On 07/28/2015 12:57 PM, Alexander Drozdov wrote:
> > 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.
> >
> > Signed-off-by: Alexander Drozdov <al.drozdov@gmail.com>
>
> Looks good to me, thanks!
>
> Acked-by: Daniel Borkmann <daniel@iogearbox.net>
> --
Fixes: 52f1454f629fa ("packet: allow to transmit +4 byte in TX_RING slot for VLAN case")
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] packet: tpacket_snd(): fix signed/unsigned comparison
2015-07-28 10:57 [PATCH] packet: tpacket_snd(): fix signed/unsigned comparison Alexander Drozdov
2015-07-28 11:07 ` Daniel Borkmann
@ 2015-07-29 7:10 ` David Miller
1 sibling, 0 replies; 4+ messages in thread
From: David Miller @ 2015-07-29 7:10 UTC (permalink / raw)
To: al.drozdov
Cc: dborkman, edumazet, willemb, viro, eyal.birger, mst, netdev,
linux-kernel
From: Alexander Drozdov <al.drozdov@gmail.com>
Date: Tue, 28 Jul 2015 13:57:01 +0300
> 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.
>
> Signed-off-by: Alexander Drozdov <al.drozdov@gmail.com>
Applied, thanks.
^ permalink raw reply [flat|nested] 4+ messages in thread
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2015-07-28 10:57 [PATCH] packet: tpacket_snd(): fix signed/unsigned comparison Alexander Drozdov
2015-07-28 11:07 ` Daniel Borkmann
2015-07-28 11:38 ` Eric Dumazet
2015-07-29 7:10 ` David Miller
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