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: 9b3eab61754d ("batman-adv: Receive fragmented packets and merge") Signed-off-by: Sven Eckelmann sven@narfation.org --- Cc: Martin Hundebøll martin@hundeboll.net
net/batman-adv/fragmentation.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/net/batman-adv/fragmentation.c b/net/batman-adv/fragmentation.c index ead18ca8..7b523e6c 100644 --- a/net/batman-adv/fragmentation.c +++ b/net/batman-adv/fragmentation.c @@ -239,8 +239,10 @@ err_unlock: spin_unlock_bh(&chain->lock);
err: - if (!ret) + if (!ret) { kfree(frag_entry_new); + 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;
out: - *skb = skb_out; ret = true; out_err: + *skb = skb_out; return ret; }