diff options
authorSven Eckelmann <>2017-02-12 11:26:33 +0100
committerSimon Wunderlich <>2017-02-21 18:33:15 +0100
commit248e23b50e2da0753f3b5faa068939cbe9f8a75a (patch)
parent4ea33ef0f9e95b69db9131d7afd98563713e81b0 (diff)
batman-adv: Fix double free during fragment merge error
The function batadv_frag_skb_buffer was supposed not to consume the skbuff on errors. This was followed in the helper function batadv_frag_insert_packet when the skb would potentially be inserted in the fragment queue. But it could happen that the next helper function batadv_frag_merge_packets would try to merge the fragments and fail. This results in a kfree_skb of all the enqueued fragments (including the just inserted one). batadv_recv_frag_packet would detect the error in batadv_frag_skb_buffer and try to free the skb again. The behavior of batadv_frag_skb_buffer (and its helper batadv_frag_insert_packet) must therefore be changed to always consume the skbuff to have a common behavior and avoid the double kfree_skb. Fixes: 610bfc6bc99b ("batman-adv: Receive fragmented packets and merge") Signed-off-by: Sven Eckelmann <> Signed-off-by: Simon Wunderlich <>
1 files changed, 5 insertions, 3 deletions
diff --git a/net/batman-adv/fragmentation.c b/net/batman-adv/fragmentation.c
index 0854ebd..31e97e9 100644
--- a/net/batman-adv/fragmentation.c
+++ b/net/batman-adv/fragmentation.c
@@ -239,8 +239,10 @@ err_unlock:
- if (!ret)
+ if (!ret) {
+ kfree_skb(skb);
+ }
return ret;
@@ -313,7 +315,7 @@ free:
* There are three possible outcomes: 1) Packet is merged: Return true and
* set *skb to merged packet; 2) Packet is buffered: Return true and set *skb
- * to NULL; 3) Error: Return false and leave skb as is.
+ * to NULL; 3) Error: Return false and free skb.
* Return: true when packet is merged or buffered, false when skb is not not
* used.
@@ -338,9 +340,9 @@ bool batadv_frag_skb_buffer(struct sk_buff **skb,
goto out_err;
- *skb = skb_out;
ret = true;
+ *skb = skb_out;
return ret;