CVE-2026-64008: accel/rocket: fix UAF via dangling GEM handle in create_bo

CVE-2026-64008: accel/rocket: fix UAF via dangling GEM handle in create_bo

[Greg Kroah-Hartman]

From: Greg Kroah-Hartman <gregkh@kernel.org>

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

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

accel/rocket: fix UAF via dangling GEM handle in create_bo

rocket_ioctl_create_bo() inserts a GEM handle into the file's IDR via
drm_gem_handle_create() early on, then performs several operations that
can fail (sgt allocation, drm_mm insert, iommu_map). If any fail after
the handle is live, the error path calls drm_gem_shmem_object_free()
which kfree's the object without removing the handle from the IDR.

This leaves a dangling handle pointing to freed slab memory. Any
subsequent ioctl using that handle (PREP_BO, FINI_BO, SUBMIT) calls
drm_gem_object_lookup() and dereferences freed memory (UAF).

Fix by moving drm_gem_handle_create() to after all fallible operations
succeed, matching the pattern used by panfrost, lima, and etnaviv.

Also fix drm_mm_insert_node_generic() whose return value was silently
overwritten by iommu_map_sgtable() on the next line. Add the missing
error check.

[tomeu: Move handle creation to the very end]

The Linux kernel CVE team has assigned CVE-2026-64008 to this issue.


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

	Issue introduced in 6.18 with commit 658ebeac33517bd3169d4b65ed801e9065d0211a and fixed in 6.18.35 with commit 18abd88d19ea195e2e1547fca0970c2f91d77a42
	Issue introduced in 6.18 with commit 658ebeac33517bd3169d4b65ed801e9065d0211a and fixed in 7.0.12 with commit 451f1ccbbdb7b65021646704b15902655f8d228a
	Issue introduced in 6.18 with commit 658ebeac33517bd3169d4b65ed801e9065d0211a and fixed in 7.1 with commit f706e6a4ce75585af979aec3dcbdce68bc76306b

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-2026-64008
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/accel/rocket/rocket_gem.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/18abd88d19ea195e2e1547fca0970c2f91d77a42
	https://git.kernel.org/stable/c/451f1ccbbdb7b65021646704b15902655f8d228a
	https://git.kernel.org/stable/c/f706e6a4ce75585af979aec3dcbdce68bc76306b