[PATCH 4.4 50/59] net: usb: lan78xx: fix possible skb leak

From: Greg Kroah-Hartman
Date: Sat Jan 11 2020 - 04:56:24 EST


From: Eric Dumazet <edumazet@xxxxxxxxxx>

[ Upstream commit 47240ba0cd09bb6fe6db9889582048324999dfa4 ]

If skb_linearize() fails, we need to free the skb.

TSO makes skb bigger, and this bug might be the reason
Raspberry Pi 3B+ users had to disable TSO.

Fixes: 55d7de9de6c3 ("Microchip's LAN7800 family USB 2/3 to 10/100/1000 Ethernet device driver")
Signed-off-by: Eric Dumazet <edumazet@xxxxxxxxxx>
Reported-by: RENARD Pierre-Francois <pfrenard@xxxxxxxxx>
Cc: Stefan Wahren <stefan.wahren@xxxxxxxx>
Cc: Woojung Huh <woojung.huh@xxxxxxxxxxxxx>
Cc: Microchip Linux Driver Support <UNGLinuxDriver@xxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/net/usb/lan78xx.c | 9 +++------
1 file changed, 3 insertions(+), 6 deletions(-)

--- a/drivers/net/usb/lan78xx.c
+++ b/drivers/net/usb/lan78xx.c
@@ -2036,11 +2036,6 @@ int lan78xx_stop(struct net_device *net)
return 0;
}

-static int lan78xx_linearize(struct sk_buff *skb)
-{
- return skb_linearize(skb);
-}
-
static struct sk_buff *lan78xx_tx_prep(struct lan78xx_net *dev,
struct sk_buff *skb, gfp_t flags)
{
@@ -2051,8 +2046,10 @@ static struct sk_buff *lan78xx_tx_prep(s
return NULL;
}

- if (lan78xx_linearize(skb) < 0)
+ if (skb_linearize(skb)) {
+ dev_kfree_skb_any(skb);
return NULL;
+ }

tx_cmd_a = (u32)(skb->len & TX_CMD_A_LEN_MASK_) | TX_CMD_A_FCS_;