Merge tag 'batadv-net-for-davem-20170301' of git://git.open-mesh.org/linux-merge

Simon Wunderlich says:

====================
Here are two batman-adv bugfixes:

 - fix a potential double free when fragment merges fail,
   by Sven Eckelmann

 - fix failing tranmission of the 16th (last) fragment if that exists,
   by Linus Lüssing
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 11 insertions, 9 deletions

diff --git a/net/batman-adv/fragmentation.c b/net/batman-adv/fragmentation.c
index ead18ca836de..11a23fd6e1a0 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;
 }
 
@@ -499,6 +501,12 @@ int batadv_frag_send_packet(struct sk_buff *skb,
 
 	/* Eat and send fragments from the tail of skb */
 	while (skb->len > max_fragment_size) {
+		/* The initial check in this function should cover this case */
+		if (unlikely(frag_header.no == BATADV_FRAG_MAX_FRAGMENTS - 1)) {
+			ret = -EINVAL;
+			goto put_primary_if;
+		}
+
 		skb_fragment = batadv_frag_create(skb, &frag_header, mtu);
 		if (!skb_fragment) {
 			ret = -ENOMEM;
@@ -515,12 +523,6 @@ int batadv_frag_send_packet(struct sk_buff *skb,
 		}
 
 		frag_header.no++;
-
-		/* The initial check in this function should cover this case */
-		if (frag_header.no == BATADV_FRAG_MAX_FRAGMENTS - 1) {
-			ret = -EINVAL;
-			goto put_primary_if;
-		}
 	}
 
 	/* Make room for the fragment header. */