[PATCH net] net: atm: fix use after free in lec_send()

From: Dan Carpenter
Date: Fri Mar 14 2025 - 06:11:20 EST


The ->send() operation frees skb so save the length before calling
->send() to avoid a use after free.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
---
net/atm/lec.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/net/atm/lec.c b/net/atm/lec.c
index ffef658862db..a948dd47c3f3 100644
--- a/net/atm/lec.c
+++ b/net/atm/lec.c
@@ -181,6 +181,7 @@ static void
lec_send(struct atm_vcc *vcc, struct sk_buff *skb)
{
struct net_device *dev = skb->dev;
+ unsigned int len = skb->len;

ATM_SKB(skb)->vcc = vcc;
atm_account_tx(vcc, skb);
@@ -191,7 +192,7 @@ lec_send(struct atm_vcc *vcc, struct sk_buff *skb)
}

dev->stats.tx_packets++;
- dev->stats.tx_bytes += skb->len;
+ dev->stats.tx_bytes += len;
}

static void lec_tx_timeout(struct net_device *dev, unsigned int txqueue)
--
2.47.2