AZL-94455

In the Linux kernel, the following vulnerability has been resolved:

wifi: p54: validate RX frame length in p54rxeeprom_readback()

p54rxeepromreadback() copies the requested EEPROM slice out of a device-supplied readback frame without checking that the skb actually holds that many bytes. Commit da1b9a55ff11 ("wifi: p54: prevent buffer-overflow in p54rxeepromreadback()") closed the destination overflow by copying a fixed priv->eepromslicesize (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->eepromslicesize 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> ... __asanmemcpy (mm/kasan/shadow.c:105) p54rx (drivers/net/wireless/intersil/p54/txrx.c:507) p54urxcb (drivers/net/wireless/intersil/p54/p54usb.c:163) _usbhcdgivebackurb (drivers/usb/core/hcd.c:1657) dummytimer (drivers/usb/gadget/udc/dummyhcd.c:2005) ... </IRQ>

The buggy address belongs to the object at ffff88800f0770c0 which belongs to the cache skbuffsmallhead 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.