linux-kernel - [PATCH] scsi: bnx2fc: fix double free of skb in bnx2fc

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Date:   Tue, 28 Dec 2021 11:03:35 +0800
From:   Yin Xiujiang <yinxiujiang@...inos.cn>
To:     skashyap@...vell.com, jhasan@...vell.com,
        GR-QLogic-Storage-Upstream@...vell.com, jejb@...ux.ibm.com,
        martin.petersen@...cle.com, yinxiujiang@...inos.cn
Cc:     linux-scsi@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH] scsi: bnx2fc: fix double free of skb in bnx2fc_rcv

In `bnx2fc_rcv`,if skb_share_check() return NULL,
the variable skb would be freed but not set to NULL,
then it would be freed  in `goto err` again.

Signed-off-by: Yin Xiujiang <yinxiujiang@...inos.cn>
---
 drivers/scsi/bnx2fc/bnx2fc_fcoe.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/drivers/scsi/bnx2fc/bnx2fc_fcoe.c b/drivers/scsi/bnx2fc/bnx2fc_fcoe.c
index 71fa62bd3083..07a91b1f05a2 100644
--- a/drivers/scsi/bnx2fc/bnx2fc_fcoe.c
+++ b/drivers/scsi/bnx2fc/bnx2fc_fcoe.c
@@ -432,7 +432,6 @@ static int bnx2fc_rcv(struct sk_buff *skb, struct net_device *dev,
 	struct fcoe_ctlr *ctlr;
 	struct fcoe_rcv_info *fr;
 	struct fcoe_percpu_s *bg;
-	struct sk_buff *tmp_skb;
 
 	interface = container_of(ptype, struct bnx2fc_interface,
 				 fcoe_packet_type);
@@ -444,11 +443,10 @@ static int bnx2fc_rcv(struct sk_buff *skb, struct net_device *dev,
 		goto err;
 	}
 
-	tmp_skb = skb_share_check(skb, GFP_ATOMIC);
-	if (!tmp_skb)
+	skb = skb_share_check(skb, GFP_ATOMIC);
+	if (unlikely(!skb))
 		goto err;
 
-	skb = tmp_skb;
 
 	if (unlikely(eth_hdr(skb)->h_proto != htons(ETH_P_FCOE))) {
 		printk(KERN_ERR PFX "bnx2fc_rcv: Wrong FC type frame\n");
-- 
2.30.0