path: root/net/ipv4/gre_offload.c
diff options
authorLi RongQing <>2014-10-18 17:26:04 +0800
committerDavid S. Miller <>2014-10-18 13:04:08 -0400
commitb4e3cef703fb21b26db053a770900f2bd910638b (patch)
tree8eb99932d3c7af0461a93467ad8b3f0549745d69 /net/ipv4/gre_offload.c
parent815afe1785da727ee48cd8e63ac4a3ec6c7459b3 (diff)
ipv4: fix a potential use after free in gre_offload.c
pskb_may_pull() may change skb->data and make greh pointer oboslete; so need to reassign greh; but since first calling pskb_may_pull already ensured that skb->data has enough space for greh, so move the reference of greh before second calling pskb_may_pull(), to avoid reassign greh. Fixes: 7a7ffbabf9("ipv4: fix tunneled VM traffic over hw VXLAN/GRE GSO NIC") Cc: Wei-Chun Chao <> Signed-off-by: Li RongQing <> Acked-by: Eric Dumazet <> Signed-off-by: David S. Miller <>
Diffstat (limited to 'net/ipv4/gre_offload.c')
1 files changed, 3 insertions, 3 deletions
diff --git a/net/ipv4/gre_offload.c b/net/ipv4/gre_offload.c
index a77729503071..ccda09628de7 100644
--- a/net/ipv4/gre_offload.c
+++ b/net/ipv4/gre_offload.c
@@ -55,13 +55,13 @@ static struct sk_buff *gre_gso_segment(struct sk_buff *skb,
if (csum)
skb->encap_hdr_csum = 1;
- if (unlikely(!pskb_may_pull(skb, ghl)))
- goto out;
/* setup inner skb. */
skb->protocol = greh->protocol;
skb->encapsulation = 0;
+ if (unlikely(!pskb_may_pull(skb, ghl)))
+ goto out;
__skb_pull(skb, ghl);
skb_set_network_header(skb, skb_inner_network_offset(skb));