In the Linux kernel, the following vulnerability has been resolved:
libceph: reject zero bucket types in crush_decode
CRUSH bucket type 0 is reserved for devices. The mapper relies on that invariant and uses type 0 to identify leaf devices.
If crush_decode() accepts a bucket with type 0, a malformed CRUSH map can make the mapper treat a negative bucket ID as a device and pass it to is_out(), which then indexes the OSD weight array with a negative value.
Reject zero bucket types while decoding the CRUSH map so the invalid state never reaches the mapper.
References
- https://git.kernel.org/stable/c/05f90284223381005d6bcddab3fda4a97f9c3401
- https://git.kernel.org/stable/c/3b2f1937f5fce8b7dd5432e7693e3cc8b5eece56
- https://git.kernel.org/stable/c/70998f91030ee083ecb336a1dff0701c20a38081
- https://git.kernel.org/stable/c/826cd1de5802fd392922785f9b64d76e65d2a100
- https://git.kernel.org/stable/c/b8a9fb6bf806f9c4891e71ae1beab0c07c23a877