4.8-stable review patch. If anyone has any objections, please let me know.
------------------
From: Eric Dumazet <edumazet@xxxxxxxxxx>
[ Upstream commit 34fad54c2537f7c99d07375e50cb30aa3c23bd83 ]
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: a6e544b0a88b ("flow_dissector: Jump to exit code in __skb_flow_dissect")
Signed-off-by: Eric Dumazet <edumazet@xxxxxxxxxx>
Reported-by: Yibin Yang <yibyang@xxxxxxxxx
Acked-by: Alexander Duyck <alexander.h.duyck@xxxxxxxxx>
Acked-by: Willem de Bruijn <willemb@xxxxxxxxxx>
Acked-by: Alexei Starovoitov <ast@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/core/flow_dissector.c | 11 ++++++++---
1 file changed, 8 insertions(+), 3 deletions(-)
--- a/net/core/flow_dissector.c
+++ b/net/core/flow_dissector.c
@@ -118,7 +118,7 @@ bool __skb_flow_dissect(const struct sk_
struct flow_dissector_key_tags *key_tags;
struct flow_dissector_key_keyid *key_keyid;
u8 ip_proto = 0;
- bool ret = false;
+ bool ret;
if (!data) {
data = skb->data;
@@ -481,12 +481,17 @@ ip_proto_again:
out_good:
ret = true;
-out_bad:
+ key_control->thoff = (u16)nhoff;
+out:
key_basic->n_proto = proto;
key_basic->ip_proto = ip_proto;
- key_control->thoff = (u16)nhoff;
return ret;
+
+out_bad:
+ ret = false;
+ key_control->thoff = min_t(u16, nhoff, skb ? skb->len : hlen);
+ goto out;
}
EXPORT_SYMBOL(__skb_flow_dissect);
--
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