netdev - [PATCH net] net: qualcomm: rmnet: Fix a double free

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Date:   Fri, 8 Sep 2017 13:23:57 +0300
From:   Dan Carpenter <dan.carpenter@...cle.com>
To:     Subash Abhinov Kasiviswanathan <subashab@...eaurora.org>
Cc:     "David S. Miller" <davem@...emloft.net>, netdev@...r.kernel.org,
        kernel-janitors@...r.kernel.org
Subject: [PATCH net] net: qualcomm: rmnet: Fix a double free

This is called from rmnet_map_ingress_handler().  When the
rmnet_map_deaggregate() returns NULL then the caller calls
consume_skb(skb) which frees the skb.  The kfree_skb() on this error
path leads to a double free.

Fixes: ceed73a2cf4a ("drivers: net: ethernet: qualcomm: rmnet: Initial implementation")
Signed-off-by: Dan Carpenter <dan.carpenter@...cle.com>
---
This is from static analysis and not tested.

diff --git a/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c b/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c
index 557c9bf1a469..0335fce54201 100644
--- a/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c
+++ b/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c
@@ -95,10 +95,8 @@ struct sk_buff *rmnet_map_deaggregate(struct sk_buff *skb)
 	skb_pull(skb, packet_len);
 
 	/* Some hardware can send us empty frames. Catch them */
-	if (ntohs(maph->pkt_len) == 0) {
-		kfree_skb(skb);
+	if (ntohs(maph->pkt_len) == 0)
 		return NULL;
-	}
 
 	return skbn;
 }