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

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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>
This commit is contained in:
Marcin Kozlowski 2022-04-06 10:05:37 +02:00 committed by David S. Miller
parent 4e910dbe36
commit afb8e24652
1 changed files with 7 additions and 2 deletions
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9
drivers/net/usb/aqc111.c
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@ -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;