Patchwork [176/241] net: Fix skb_under_panic oops in neigh_resolve_output

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Submitter Herton Ronaldo Krzesinski
Date Dec. 13, 2012, 1:59 p.m.
Message ID <1355407206-17100-177-git-send-email-herton.krzesinski@canonical.com>
Download mbox | patch
Permalink /patch/206022/
State New
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Comments

Herton Ronaldo Krzesinski - Dec. 13, 2012, 1:59 p.m.
3.5.7.2 -stable review patch.  If anyone has any objections, please let me know.

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

From: "ramesh.nagappa@gmail.com" <ramesh.nagappa@gmail.com>

commit e1f165032c8bade3a6bdf546f8faf61fda4dd01c upstream.

The retry loop in neigh_resolve_output() and neigh_connected_output()
call dev_hard_header() with out reseting the skb to network_header.
This causes the retry to fail with skb_under_panic. The fix is to
reset the network_header within the retry loop.

Signed-off-by: Ramesh Nagappa <ramesh.nagappa@ericsson.com>
Reviewed-by: Shawn Lu <shawn.lu@ericsson.com>
Reviewed-by: Robert Coulson <robert.coulson@ericsson.com>
Reviewed-by: Billie Alsup <billie.alsup@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Herton Ronaldo Krzesinski <herton.krzesinski@canonical.com>
---
 net/core/neighbour.c |    6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

Patch

diff --git a/net/core/neighbour.c b/net/core/neighbour.c
index d81d026..5c2dac3 100644
--- a/net/core/neighbour.c
+++ b/net/core/neighbour.c
@@ -1286,8 +1286,6 @@  int neigh_resolve_output(struct neighbour *neigh, struct sk_buff *skb)
 	if (!dst)
 		goto discard;
 
-	__skb_pull(skb, skb_network_offset(skb));
-
 	if (!neigh_event_send(neigh, skb)) {
 		int err;
 		struct net_device *dev = neigh->dev;
@@ -1297,6 +1295,7 @@  int neigh_resolve_output(struct neighbour *neigh, struct sk_buff *skb)
 			neigh_hh_init(neigh, dst);
 
 		do {
+			__skb_pull(skb, skb_network_offset(skb));
 			seq = read_seqbegin(&neigh->ha_lock);
 			err = dev_hard_header(skb, dev, ntohs(skb->protocol),
 					      neigh->ha, NULL, skb->len);
@@ -1327,9 +1326,8 @@  int neigh_connected_output(struct neighbour *neigh, struct sk_buff *skb)
 	unsigned int seq;
 	int err;
 
-	__skb_pull(skb, skb_network_offset(skb));
-
 	do {
+		__skb_pull(skb, skb_network_offset(skb));
 		seq = read_seqbegin(&neigh->ha_lock);
 		err = dev_hard_header(skb, dev, ntohs(skb->protocol),
 				      neigh->ha, NULL, skb->len);