3.16.44-rc1 review patch. If anyone has any objections, please let me know.
------------------ From: Sven Eckelmann <[email protected]> commit 248e23b50e2da0753f3b5faa068939cbe9f8a75a upstream. 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 <[email protected]> Signed-off-by: Simon Wunderlich <[email protected]> [bwh: Backported to 3.16: adjust context] Signed-off-by: Ben Hutchings <[email protected]> --- net/batman-adv/fragmentation.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) --- a/net/batman-adv/fragmentation.c +++ b/net/batman-adv/fragmentation.c @@ -212,8 +212,10 @@ err_unlock: spin_unlock_bh(&chain->lock); err: - if (!ret) + if (!ret) { kfree(frag_entry_new); + kfree_skb(skb); + } return ret; } @@ -288,7 +290,7 @@ 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. */ bool batadv_frag_skb_buffer(struct sk_buff **skb, struct batadv_orig_node *orig_node_src) @@ -310,9 +312,9 @@ bool batadv_frag_skb_buffer(struct sk_bu goto out_err; out: - *skb = skb_out; ret = true; out_err: + *skb = skb_out; return ret; }
