Subject: CVE-2024-44993: drm/v3d: Fix out-of-bounds read in `v3d_csd_job_run()`

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

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

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

drm/v3d: Fix out-of-bounds read in `v3d_csd_job_run()`

When enabling UBSAN on Raspberry Pi 5, we get the following warning:

[  387.894977] UBSAN: array-index-out-of-bounds in drivers/gpu/drm/v3d/v3d_sched.c:320:3
[  387.903868] index 7 is out of range for type '__u32 [7]'
[  387.909692] CPU: 0 PID: 1207 Comm: kworker/u16:2 Tainted: G        WC         6.10.3-v8-16k-numa #151
[  387.919166] Hardware name: Raspberry Pi 5 Model B Rev 1.0 (DT)
[  387.925961] Workqueue: v3d_csd drm_sched_run_job_work [gpu_sched]
[  387.932525] Call trace:
[  387.935296]  dump_backtrace+0x170/0x1b8
[  387.939403]  show_stack+0x20/0x38
[  387.942907]  dump_stack_lvl+0x90/0xd0
[  387.946785]  dump_stack+0x18/0x28
[  387.950301]  __ubsan_handle_out_of_bounds+0x98/0xd0
[  387.955383]  v3d_csd_job_run+0x3a8/0x438 [v3d]
[  387.960707]  drm_sched_run_job_work+0x520/0x6d0 [gpu_sched]
[  387.966862]  process_one_work+0x62c/0xb48
[  387.971296]  worker_thread+0x468/0x5b0
[  387.975317]  kthread+0x1c4/0x1e0
[  387.978818]  ret_from_fork+0x10/0x20
[  387.983014] ---[ end trace ]---

This happens because the UAPI provides only seven configuration
registers and we are reading the eighth position of this u32 array.

Therefore, fix the out-of-bounds read in `v3d_csd_job_run()` by
accessing only seven positions on the '__u32 [7]' array. The eighth
register exists indeed on V3D 7.1, but it isn't currently used. That
being so, let's guarantee that it remains unused and add a note that it
could be set in a future patch.

The Linux kernel CVE team has assigned CVE-2024-44993 to this issue.

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

	Issue introduced in 6.8 with commit 0ad5bc1ce463 and fixed in 6.10.7 with commit d656b82c4b30
	Issue introduced in 6.8 with commit 0ad5bc1ce463 and fixed in 6.11 with commit 497d370a644d

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-2024-44993
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/v3d/v3d_sched.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/d656b82c4b30cf12715e6cd129d3df808fde24a7
	https://git.kernel.org/stable/c/497d370a644d95a9f04271aa92cb96d32e84c770