From fc7f750dc9d102c1ed7bbe4591f991e770c99033 Mon Sep 17 00:00:00 2001
From: Dan Carpenter <dan.carpenter@oracle.com>
Date: Mon, 28 Feb 2022 10:43:31 +0300
Subject: [PATCH] staging: gdm724x: fix use after free in gdm_lte_rx()
Git-commit: fc7f750dc9d102c1ed7bbe4591f991e770c99033
Patch-mainline: v5.17
References: git-fixes

The netif_rx_ni() function frees the skb so we can't dereference it to
save the skb->len.

Fixes: 61e121047645 ("staging: gdm7240: adding LTE USB driver")
Cc: stable <stable@vger.kernel.org>
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Link: https://lore.kernel.org/r/20220228074331.GA13685@kili
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/staging/gdm724x/gdm_lte.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/staging/gdm724x/gdm_lte.c b/drivers/staging/gdm724x/gdm_lte.c
index 493ed4821515..0d8d8fed283d 100644
--- a/drivers/staging/gdm724x/gdm_lte.c
+++ b/drivers/staging/gdm724x/gdm_lte.c
@@ -76,14 +76,15 @@ static void tx_complete(void *arg)
 
 static int gdm_lte_rx(struct sk_buff *skb, struct nic *nic, int nic_type)
 {
-	int ret;
+	int ret, len;
 
+	len = skb->len + ETH_HLEN;
 	ret = netif_rx_ni(skb);
 	if (ret == NET_RX_DROP) {
 		nic->stats.rx_dropped++;
 	} else {
 		nic->stats.rx_packets++;
-		nic->stats.rx_bytes += skb->len + ETH_HLEN;
+		nic->stats.rx_bytes += len;
 	}
 
 	return 0;
-- 
2.31.1