AZL-99492

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

HID: magicmouse: prevent unbounded recursion in magicmouserawevent()

magicmouserawevent() handles DOUBLEREPORTID (0xf7) packets, which pack two touch reports into one, by splitting the packet and calling itself on each half. The only guard against runaway recursion is a "size < 1" check, which stops zero-sized calls but does not bound the recursion depth.

A malicious HID device that matches this driver can send a report starting with DOUBLEREPORTID and filled with the sequence [0xf7, 0x00]. Each level consumes two bytes and recurses on the remainder, so an incoming report of up to HIDMAXBUFFERSIZE (16 KiB) drives roughly 8000 nested calls. That easily exhausts the 16 KiB kernel stack, leading to a stack overflow: a panic with CONFIGVMAP_STACK, or memory corruption without it.

A double report only ever wraps two normal reports; it is never legitimately nested. Refuse to re-enter the DOUBLEREPORTID case from a recursive call so the recursion depth is bounded to two, while all valid packets keep being parsed exactly as before.