[PATCH 4.19 05/34] sr9700: sanity check for packet length

Greg Kroah-Hartman
2022-02-28T17:32:08Z

From: Oliver Neukum <oneukum@suse.com>

commit e9da0b56fe27206b49f39805f7dcda8a89379062 upstream.

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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/net/usb/sr9700.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/net/usb/sr9700.c
+++ b/drivers/net/usb/sr9700.c
@@ -410,7 +410,7 @@ static int sr9700_rx_fixup(struct usbnet
/* 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 */