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wifi: p54: validate RX frame length in p54_rx_eeprom_readback()

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p54_rx_eeprom_readback() copies the requested EEPROM slice out of a
device-supplied readback frame without checking that the skb actually holds
that many bytes. Commit da1b9a55ff ("wifi: p54: prevent buffer-overflow in
p54_rx_eeprom_readback()") closed the destination overflow by copying a
fixed priv->eeprom_slice_size (and rejecting a mismatched advertised len),
but the source side is still unbounded: nothing verifies the frame is long
enough to supply that many bytes.

A malicious USB device can send a short frame whose advertised len matches
priv->eeprom_slice_size while the payload is truncated. The equality check
passes and memcpy() reads past the end of the skb, leaking adjacent heap:

  BUG: KASAN: slab-out-of-bounds in p54_rx (drivers/net/wireless/intersil/p54/txrx.c:507)
  Read of size 1016 at addr ffff88800f077114 by task swapper/0/0
  Call Trace:
   <IRQ>
   ...
   __asan_memcpy (mm/kasan/shadow.c:105)
   p54_rx (drivers/net/wireless/intersil/p54/txrx.c:507)
   p54u_rx_cb (drivers/net/wireless/intersil/p54/p54usb.c:163)
   __usb_hcd_giveback_urb (drivers/usb/core/hcd.c:1657)
   dummy_timer (drivers/usb/gadget/udc/dummy_hcd.c:2005)
   ...
   </IRQ>

  The buggy address belongs to the object at ffff88800f0770c0
   which belongs to the cache skbuff_small_head of size 704
  The buggy address is located 84 bytes inside of
   allocated 704-byte region [ffff88800f0770c0, ffff88800f077380)

Check that the slice fits in the skb before copying.

Fixes: 7cb770729b ("p54: move eeprom code into common library")
Reported-by: Weiming Shi <bestswngs@gmail.com>
Assisted-by: Claude:claude-opus-4-8
Signed-off-by: Xiang Mei <xmei5@asu.edu>
Acked-by: Christian Lamparter <chunkeey@gmail.com>
Link: https://patch.msgid.link/20260628000510.4152481-1-xmei5@asu.edu
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
This commit is contained in:
Xiang Mei 2026-06-27 17:05:10 -07:00 committed by Johannes Berg
parent aa2eb62525
commit ebd6d37fa9
1 changed files with 8 additions and 0 deletions
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8
drivers/net/wireless/intersil/p54/txrx.c
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@ -499,11 +499,19 @@ static void p54_rx_eeprom_readback(struct p54_common *priv,
if (le16_to_cpu(eeprom->v2.len) != priv->eeprom_slice_size)
return;
if (eeprom->v2.data + priv->eeprom_slice_size >
skb_tail_pointer(skb))
return;
memcpy(priv->eeprom, eeprom->v2.data, priv->eeprom_slice_size);
} else {
if (le16_to_cpu(eeprom->v1.len) != priv->eeprom_slice_size)
return;
if (eeprom->v1.data + priv->eeprom_slice_size >
skb_tail_pointer(skb))
return;
memcpy(priv->eeprom, eeprom->v1.data, priv->eeprom_slice_size);
}