CVE-2026-68259: drm/amdkfd: Check bounds in allocate_event_notification_slot

From: Greg Kroah-Hartman <[email protected]>

Description
===========

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

drm/amdkfd: Check bounds in allocate_event_notification_slot

The valid event ids go from 0 to KFD_SIGNAL_EVENT_LIMIT

allocate_event_notification_slot has an option to specify
an event id to allocate at, used by CRIU. We weren't checking
the bounds on that value.

Check them.

v2: Lower bounds check is unecessary because of idr_alloc
already rejecting negative numbers. Upper bounds check should
be KFD_SIGNAL_EVENT_LIMIT since the signal mode mappings might
not yet exist

(cherry picked from commit 6853f1f6cbbeb3f53ebbbd7286536aeb2c5d5f50)

The Linux kernel CVE team has assigned CVE-2026-68259 to this issue.


Affected and fixed versions
===========================

	Fixed in 6.6.148 with commit 85eedff5f0c4aba5a66bc37a1bd6bcecd0d77b53
	Fixed in 6.12.101 with commit 4622214f0542f64b02c250db0f9c677eeb032d9b
	Fixed in 6.18.42 with commit 50319efb865f72db45f191c8709511746d58ee0a
	Fixed in 7.1.6 with commit abeeb1947d81610c65349db4d89c6151f270e136
	Fixed in 7.2-rc3 with commit bb52249fbbe948875155ccd45cd8d74bf4ae747b

Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2026-68259
will be updated if fixes are backported, please check that for the most
up to date information about this issue.


Affected files
==============

The file(s) affected by this issue are:
	drivers/gpu/drm/amd/amdkfd/kfd_events.c


Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/85eedff5f0c4aba5a66bc37a1bd6bcecd0d77b53
	https://git.kernel.org/stable/c/4622214f0542f64b02c250db0f9c677eeb032d9b
	https://git.kernel.org/stable/c/50319efb865f72db45f191c8709511746d58ee0a
	https://git.kernel.org/stable/c/abeeb1947d81610c65349db4d89c6151f270e136
	https://git.kernel.org/stable/c/bb52249fbbe948875155ccd45cd8d74bf4ae747b