lkml.org 
[lkml]   [2016]   [Nov]   [19]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 4.4 14/37] net: __skb_flow_dissect() must cap its return value
Date
4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Eric Dumazet <edumazet@google.com>


[ 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@google.com>
Reported-by: Yibin Yang <yibyang@cisco.com
Acked-by: Alexander Duyck <alexander.h.duyck@intel.com>
Acked-by: Willem de Bruijn <willemb@google.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
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
@@ -131,7 +131,7 @@ 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;
@@ -492,12 +492,17 @@ 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);


\
 
 \ /
  Last update: 2016-11-19 10:41    [W:0.188 / U:0.108 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site