* [PATCH] ipv6: gre: correct calculation of max_headroom
@ 2013-09-29 3:40 Hannes Frederic Sowa
2013-09-29 8:05 ` Eric Dumazet
2013-10-01 5:04 ` David Miller
0 siblings, 2 replies; 3+ messages in thread
From: Hannes Frederic Sowa @ 2013-09-29 3:40 UTC (permalink / raw)
To: netdev; +Cc: xeb
gre_hlen already accounts for sizeof(struct ipv6_hdr) + gre header,
so initialize max_headroom to zero. Otherwise the
if (encap_limit >= 0) {
max_headroom += 8;
mtu -= 8;
}
increments an uninitialized variable before max_headroom was reset.
Found with coverity: 728539
Cc: Dmitry Kozlov <xeb@mail.ru>
Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
---
net/ipv6/ip6_gre.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/net/ipv6/ip6_gre.c b/net/ipv6/ip6_gre.c
index 6b26e9f..7bb5446 100644
--- a/net/ipv6/ip6_gre.c
+++ b/net/ipv6/ip6_gre.c
@@ -618,7 +618,7 @@ static netdev_tx_t ip6gre_xmit2(struct sk_buff *skb,
struct ip6_tnl *tunnel = netdev_priv(dev);
struct net_device *tdev; /* Device to other host */
struct ipv6hdr *ipv6h; /* Our new IP header */
- unsigned int max_headroom; /* The extra header space needed */
+ unsigned int max_headroom = 0; /* The extra header space needed */
int gre_hlen;
struct ipv6_tel_txoption opt;
int mtu;
@@ -693,7 +693,7 @@ static netdev_tx_t ip6gre_xmit2(struct sk_buff *skb,
skb_scrub_packet(skb, !net_eq(tunnel->net, dev_net(dev)));
- max_headroom = LL_RESERVED_SPACE(tdev) + gre_hlen + dst->header_len;
+ max_headroom += LL_RESERVED_SPACE(tdev) + gre_hlen + dst->header_len;
if (skb_headroom(skb) < max_headroom || skb_shared(skb) ||
(skb_cloned(skb) && !skb_clone_writable(skb, 0))) {
--
1.8.3.1
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] ipv6: gre: correct calculation of max_headroom
2013-09-29 3:40 [PATCH] ipv6: gre: correct calculation of max_headroom Hannes Frederic Sowa
@ 2013-09-29 8:05 ` Eric Dumazet
2013-10-01 5:04 ` David Miller
1 sibling, 0 replies; 3+ messages in thread
From: Eric Dumazet @ 2013-09-29 8:05 UTC (permalink / raw)
To: Hannes Frederic Sowa; +Cc: netdev, xeb
On Sun, 2013-09-29 at 05:40 +0200, Hannes Frederic Sowa wrote:
> gre_hlen already accounts for sizeof(struct ipv6_hdr) + gre header,
> so initialize max_headroom to zero. Otherwise the
>
> if (encap_limit >= 0) {
> max_headroom += 8;
> mtu -= 8;
> }
>
> increments an uninitialized variable before max_headroom was reset.
>
> Found with coverity: 728539
>
> Cc: Dmitry Kozlov <xeb@mail.ru>
> Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
> ---
Acked-by: Eric Dumazet <edumazet@google.com>
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] ipv6: gre: correct calculation of max_headroom
2013-09-29 3:40 [PATCH] ipv6: gre: correct calculation of max_headroom Hannes Frederic Sowa
2013-09-29 8:05 ` Eric Dumazet
@ 2013-10-01 5:04 ` David Miller
1 sibling, 0 replies; 3+ messages in thread
From: David Miller @ 2013-10-01 5:04 UTC (permalink / raw)
To: hannes; +Cc: netdev, xeb
From: Hannes Frederic Sowa <hannes@stressinduktion.org>
Date: Sun, 29 Sep 2013 05:40:50 +0200
> gre_hlen already accounts for sizeof(struct ipv6_hdr) + gre header,
> so initialize max_headroom to zero. Otherwise the
>
> if (encap_limit >= 0) {
> max_headroom += 8;
> mtu -= 8;
> }
>
> increments an uninitialized variable before max_headroom was reset.
>
> Found with coverity: 728539
>
> Cc: Dmitry Kozlov <xeb@mail.ru>
> Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Applied and queued up for -stable, thanks.
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2013-10-01 4:57 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2013-09-29 3:40 [PATCH] ipv6: gre: correct calculation of max_headroom Hannes Frederic Sowa
2013-09-29 8:05 ` Eric Dumazet
2013-10-01 5:04 ` David Miller
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).