From: Oliver Neukum <oneukum@suse.com>
Date: Thu, 17 Feb 2022 13:10:44 +0000 (+0100)
Subject: sr9700: sanity check for packet length
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=89260e0e191e8a3a9872f72836bdf0641853c87f;p=GitHub%2FLineageOS%2FG12%2Fandroid_kernel_amlogic_linux-4.9.git

sr9700: sanity check for packet length

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>
---

diff --git a/drivers/net/usb/sr9700.c b/drivers/net/usb/sr9700.c
index aadfe1d1c37e..f4c4df01874c 100644
--- a/drivers/net/usb/sr9700.c
+++ b/drivers/net/usb/sr9700.c
@@ -409,7 +409,7 @@ 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 */