diff options
| author | Sven Eckelmann <sven@narfation.org> | 2020-03-18 00:27:11 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-03-20 09:06:28 +0100 |
| commit | 1274e5f1c58657f52ca018b4f05d45301d7eba9c (patch) | |
| tree | 45b1245ec5af1990b6890b5d30d39b54fcebb323 | |
| parent | 1428d490247cbe82d3d84dff8fea225f2199b4b1 (diff) | |
batman-adv: Fix double free during fragment merge error
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 <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | net/batman-adv/fragmentation.c | 6 | ||||
| -rw-r--r-- | net/batman-adv/routing.c | 6 |
2 files changed, 10 insertions, 2 deletions
diff --git a/net/batman-adv/fragmentation.c b/net/batman-adv/fragmentation.c index d50c3b003dc9..8605e3c7958d 100644 --- a/net/batman-adv/fragmentation.c +++ b/net/batman-adv/fragmentation.c @@ -233,8 +233,10 @@ err_unlock: spin_unlock_bh(&chain->lock); err: - if (!ret) + if (!ret) { kfree(frag_entry_new); + kfree_skb(skb); + } return ret; } @@ -329,9 +331,9 @@ 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; } diff --git a/net/batman-adv/routing.c b/net/batman-adv/routing.c index 39b4c6ab3e71..6c3dfd65023f 100644 --- a/net/batman-adv/routing.c +++ b/net/batman-adv/routing.c @@ -1053,6 +1053,12 @@ int batadv_recv_frag_packet(struct sk_buff *skb, batadv_inc_counter(bat_priv, BATADV_CNT_FRAG_RX); batadv_add_counter(bat_priv, BATADV_CNT_FRAG_RX_BYTES, skb->len); + /* batadv_frag_skb_buffer will always consume the skb and + * the caller should therefore never try to free the + * skb after this point + */ + ret = NET_RX_SUCCESS; + /* Add fragment to buffer and merge if possible. */ if (!batadv_frag_skb_buffer(&skb, orig_node_src)) goto out; |