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authorLorenzo Bianconi <lorenzo.bianconi@redhat.com>2019-04-09 12:47:20 +0300
committerDavid S. Miller <davem@davemloft.net>2019-04-11 09:02:23 +0300
commit988dc4a9a3b66be75b30405a5494faf0dc7cffb6 (patch)
treefe658830a34a330da5c2d403a7f5b059eeff4991
parentd1841533e54876f152a30ac398a34f47ad6590b1 (diff)
downloadlinux-988dc4a9a3b66be75b30405a5494faf0dc7cffb6.tar.xz
net: fou: do not use guehdr after iptunnel_pull_offloads in gue_udp_recv
gue tunnels run iptunnel_pull_offloads on received skbs. This can determine a possible use-after-free accessing guehdr pointer since the packet will be 'uncloned' running pskb_expand_head if it is a cloned gso skb (e.g if the packet has been sent though a veth device) Fixes: a09a4c8dd1ec ("tunnels: Remove encapsulation offloads on decap") Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--net/ipv4/fou.c4
1 files changed, 3 insertions, 1 deletions
diff --git a/net/ipv4/fou.c b/net/ipv4/fou.c
index 79e98e21cdd7..12ce6c526d72 100644
--- a/net/ipv4/fou.c
+++ b/net/ipv4/fou.c
@@ -121,6 +121,7 @@ static int gue_udp_recv(struct sock *sk, struct sk_buff *skb)
struct guehdr *guehdr;
void *data;
u16 doffset = 0;
+ u8 proto_ctype;
if (!fou)
return 1;
@@ -212,13 +213,14 @@ static int gue_udp_recv(struct sock *sk, struct sk_buff *skb)
if (unlikely(guehdr->control))
return gue_control_message(skb, guehdr);
+ proto_ctype = guehdr->proto_ctype;
__skb_pull(skb, sizeof(struct udphdr) + hdrlen);
skb_reset_transport_header(skb);
if (iptunnel_pull_offloads(skb))
goto drop;
- return -guehdr->proto_ctype;
+ return -proto_ctype;
drop:
kfree_skb(skb);