[PATCH AUTOSEL 5.15 12/23] sr9700: sanity check for packet length

Sasha Levin
2022-03-01T20:18:36Z

From: Oliver Neukum <oneukum@suse.com>

[ Upstream commit e9da0b56fe27206b49f39805f7dcda8a89379062 ]

A malicious device can leak heap data to user space
providing bogus frame lengths. Introduce a sanity check.

Signed-off-by: Oliver Neukum <oneukum@suse.com>
Reviewed-by: Grant Grundler <grundler@chromium.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/net/usb/sr9700.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/usb/sr9700.c b/drivers/net/usb/sr9700.c
index 6516a37893e27..0c50f24671da3 100644
--- a/drivers/net/usb/sr9700.c
+++ b/drivers/net/usb/sr9700.c
@@ -410,7 +410,7 @@ static int sr9700_rx_fixup(struct usbnet *dev, struct sk_buff *skb)
/* ignore the CRC length */
len = (skb->data[1] | (skb->data[2] << 8)) - 4;

- if (len > ETH_FRAME_LEN)
+ if (len > ETH_FRAME_LEN || len > skb->len)
return 0;

/* the last packet of current skb */
--
2.34.1