Commit 34fad54c authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

net: __skb_flow_dissect() must cap its return value

After Tom patch, thoff field could point past the end of the buffer,
this could fool some callers.

If an skb was provided, skb->len should be the upper limit.
If not, hlen is supposed to be the upper limit.

Fixes: a6e544b0

 ("flow_dissector: Jump to exit code in __skb_flow_dissect")
Signed-off-by: default avatarEric Dumazet <>
Reported-by: Yibin Yang <
Acked-by: default avatarAlexander Duyck <>
Acked-by: default avatarWillem de Bruijn <>
Acked-by: default avatarAlexei Starovoitov <>
Signed-off-by: default avatarDavid S. Miller <>
parent 79774d6b
......@@ -122,7 +122,7 @@ bool __skb_flow_dissect(const struct sk_buff *skb,
struct flow_dissector_key_keyid *key_keyid;
bool skip_vlan = false;
u8 ip_proto = 0;
bool ret = false;
bool ret;
if (!data) {
data = skb->data;
......@@ -549,12 +549,17 @@ bool __skb_flow_dissect(const struct sk_buff *skb,
ret = true;
key_control->thoff = (u16)nhoff;
key_basic->n_proto = proto;
key_basic->ip_proto = ip_proto;
key_control->thoff = (u16)nhoff;
return ret;
ret = false;
key_control->thoff = min_t(u16, nhoff, skb ? skb->len : hlen);
goto out;
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