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authorEric Dumazet <eric.dumazet@gmail.com>2011-10-14 04:57:46 +0000
committerDavid S. Miller <davem@davemloft.net>2011-10-20 16:20:30 -0400
commit113ab386c7d6625cff284fb10952ff69a58c18a4 (patch)
tree1334a0c133d6348f72619fdc502088644fba1c3b /net/ipv4/ip_gre.c
parentfd11e153b82ad1c84ccc71ba1cfedc222465198c (diff)
ip_gre: dont increase dev->needed_headroom on a live device
It seems ip_gre is able to change dev->needed_headroom on the fly. Its is not legal unfortunately and triggers a BUG in raw_sendmsg() skb = sock_alloc_send_skb(sk, ... + LL_ALLOCATED_SPACE(rt->dst.dev) < another cpu change dev->needed_headromm (making it bigger) ... skb_reserve(skb, LL_RESERVED_SPACE(rt->dst.dev)); We end with LL_RESERVED_SPACE() being bigger than LL_ALLOCATED_SPACE() -> we crash later because skb head is exhausted. Bug introduced in commit 243aad83 in 2.6.34 (ip_gre: include route header_len in max_headroom calculation) Reported-by: Elmar Vonlanthen <evonlanthen@gmail.com> Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> CC: Timo Teräs <timo.teras@iki.fi> CC: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/ip_gre.c')
-rw-r--r--net/ipv4/ip_gre.c2
1 files changed, 0 insertions, 2 deletions
diff --git a/net/ipv4/ip_gre.c b/net/ipv4/ip_gre.c
index d7bb94c48345..d55110e93120 100644
--- a/net/ipv4/ip_gre.c
+++ b/net/ipv4/ip_gre.c
@@ -835,8 +835,6 @@ static netdev_tx_t ipgre_tunnel_xmit(struct sk_buff *skb, struct net_device *dev
if (skb_headroom(skb) < max_headroom || skb_shared(skb)||
(skb_cloned(skb) && !skb_clone_writable(skb, 0))) {
struct sk_buff *new_skb = skb_realloc_headroom(skb, max_headroom);
- if (max_headroom > dev->needed_headroom)
- dev->needed_headroom = max_headroom;
if (!new_skb) {
ip_rt_put(rt);
dev->stats.tx_dropped++;