Commit 404998a1 authored Apr 06, 2022 by Marcin Kozlowski Committed by Greg Kroah-Hartman Apr 20, 2022

net: usb: aqc111: Fix out-of-bounds accesses in RX fixup



[ Upstream commit afb8e246527536848b9b4025b40e613edf776a9d ]

aqc111_rx_fixup() contains several out-of-bounds accesses that can be
triggered by a malicious (or defective) USB device, in particular:

 - The metadata array (desc_offset..desc_offset+2*pkt_count) can be out of bounds,
   causing OOB reads and (on big-endian systems) OOB endianness flips.
 - A packet can overlap the metadata array, causing a later OOB
   endianness flip to corrupt data used by a cloned SKB that has already
   been handed off into the network stack.
 - A packet SKB can be constructed whose tail is far beyond its end,
   causing out-of-bounds heap data to be considered part of the SKB's
   data.

Found doing variant analysis. Tested it with another driver (ax88179_178a), since
I don't have a aqc111 device to test it, but the code looks very similar.

Signed-off-by: Marcin Kozlowski <marcinguy@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>

parent 4a244167

drivers/net/usb/aqc111.c

+7 −2

Original line number	Diff line number	Diff line
		@@ -1102,10 +1102,15 @@ static int aqc111_rx_fixup(struct usbnet dev, struct sk_buff skb)
		if (start_of_descs != desc_offset)
		goto err;

		/* self check desc_offset from header*/
		if (desc_offset >= skb_len)
		/* self check desc_offset from header and make sure that the
		* bounds of the metadata array are inside the SKB
		*/
		if (pkt_count * 2 + desc_offset >= skb_len)
		goto err;

		/* Packets must not overlap the metadata array */
		skb_trim(skb, desc_offset);

		if (pkt_count == 0)
		goto err;