CVE-2026-89442platform/x86: ISST: Validate socket ID in clos_assoc ioctl

Official description

In the Linux kernel, the following vulnerability has been resolved: platform/x86: ISST: Validate socket ID in clos_assoc ioctl isst_if_clos_assoc() validates the user-supplied socket_id with 'socket_id > topology_max_packages()', but isst_common.sst_inst[] is allocated with topology_max_packages() entries, so the valid index range is [0, topology_max_packages()). The '>' comparison lets socket_id == topology_max_packages() pass and index one entry past the array. In addition, isst_common.sst_inst[socket_id] is NULL for an in-range package that has no bound TPMI SST instance, and the pointer is used without a NULL check. Both the out-of-bounds entry and the NULL pointer are then dereferenced by map_partition_power_domain_id() and the following power_domain_info access. Reject socket_id >= topology_max_packages() and a NULL sst_inst, matching the checks already performed by get_instance().

Affected packages & fixed versions

Affected products (as reported)

References

• https://git.kernel.org/stable/c/c847ea4851ecfa3462cc711ded2c3c3dd8d08ab8
• https://git.kernel.org/stable/c/0d90ab5f80e19cddfeb0c9fab47a1f34aa932075
• https://git.kernel.org/stable/c/82e707eff9e3b7ef6d96ecc23ea8876d20c7d6ca
• https://git.kernel.org/stable/c/207b4dc6eb100141b122b2602504a1429a4b6558
• https://git.kernel.org/stable/c/a89f07db0cb95c54dac4a8406c79a04e44a73c3c