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| author | Lorenzo Bianconi <lorenzo.bianconi@redhat.com> | 2019-04-09 12:47:20 +0300 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2019-04-11 09:02:23 +0300 |
| commit | 988dc4a9a3b66be75b30405a5494faf0dc7cffb6 (patch) | |
| tree | fe658830a34a330da5c2d403a7f5b059eeff4991 | |
| parent | d1841533e54876f152a30ac398a34f47ad6590b1 (diff) | |
| download | linux-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.c | 4 |
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); |