[PATCH] scsi/bnx2fc/bnx2fx_fcore: Fix a double free in bnx2fc_rcv

From: Lv Yunlong
Date: Sun Mar 28 2021 - 04:17:05 EST


In bnx2fc_rcv, it calls skb_share_check(skb,GFP_ATOMIC) to clone
the skb. But if skb_clone() failed, skb_share_check() will free
the skb in the first time and return NULL. Then skb_share_check()
returns NULL and goto err.

Unfortunately, the same skb is freed in the second time in err.

I think moving skb = tmp_skb in front of if(!tmp_err) goto err
is a good solution, because freeing a NULL skb is safe.

Fixes: 01a4cc4d0cd6a ("bnx2fc: do not add shared skbs to the fcoe_rx_list")
Signed-off-by: Lv Yunlong <lyl2019@xxxxxxxxxxxxxxxx>
---
drivers/scsi/bnx2fc/bnx2fc_fcoe.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/scsi/bnx2fc/bnx2fc_fcoe.c b/drivers/scsi/bnx2fc/bnx2fc_fcoe.c
index 16bb6d2f98de..2e213d336ebe 100644
--- a/drivers/scsi/bnx2fc/bnx2fc_fcoe.c
+++ b/drivers/scsi/bnx2fc/bnx2fc_fcoe.c
@@ -445,11 +445,11 @@ static int bnx2fc_rcv(struct sk_buff *skb, struct net_device *dev,
}

tmp_skb = skb_share_check(skb, GFP_ATOMIC);
+ skb = tmp_skb;
+
if (!tmp_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");
goto err;
--
2.25.1