title: media: mtk-jpeg: Fix use after free bug due to error path handling in mtk_jpeg_dec_device_run
description: In the Linux kernel, the following vulnerability has been resolved:
media: mtk-jpeg: Fix use after free bug due to error path handling in mtk_jpeg_dec_device_run
In mtk_jpeg_probe, &jpeg->job_timeout_work is bound with
mtk_jpeg_job_timeout_work.
In mtk_jpeg_dec_device_run, if error happens in
mtk_jpeg_set_dec_dst, it will finally start the worker while
mark the job as finished by invoking v4l2_m2m_job_finish.
There are two methods to trigger the bug. If we remove the
module, it which will call mtk_jpeg_remove to make cleanup.
The possible sequence is as follows, which will cause a
use-after-free bug.
CPU0                  CPU1
mtk_jpeg_dec_...    |
start worker	    |
|mtk_jpeg_job_timeout_work
mtk_jpeg_remove     |
v4l2_m2m_release  |
kfree(m2m_dev); |
|
| v4l2_m2m_get_curr_priv
|   m2m_dev->curr_ctx //use
If we close the file descriptor, which will call mtk_jpeg_release,
it will have a similar sequence.
Fix this bug by starting timeout worker only if started jpegdec worker
successfully. Then v4l2_m2m_job_finish will only be called in
either mtk_jpeg_job_timeout_work or mtk_jpeg_dec_device_run.
affected:
{
product: Linux
vendor: Linux
defaultStatus: unaffected
repo: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
versions:
version: b2f0d2724ba4, lessThan: 43872f44eee6, status: affected, versionType: git
version: b2f0d2724ba4, lessThan: 1b1036c60a37, status: affected, versionType: git
version: b2f0d2724ba4, lessThan: 9fec4db7fff5, status: affected, versionType: git
version: b2f0d2724ba4, lessThan: 8254d54d00eb, status: affected, versionType: git
version: b2f0d2724ba4, lessThan: 6e2f37022f0f, status: affected, versionType: git
version: b2f0d2724ba4, lessThan: 206c857dd17d, status: affected, versionType: git
}
{
product: Linux
vendor: Linux
defaultStatus: affected
repo: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
versions:
version: 4.12, status: affected
version: 0, lessThan: 4.12, status: unaffected, versionType: custom
version: 5.10.210, lessThanOrEqual: 5.10.*, status: unaffected, versionType: custom
version: 5.15.149, lessThanOrEqual: 5.15.*, status: unaffected, versionType: custom
version: 6.1.76, lessThanOrEqual: 6.1.*, status: unaffected, versionType: custom
version: 6.6.15, lessThanOrEqual: 6.6.*, status: unaffected, versionType: custom
version: 6.7.3, lessThanOrEqual: 6.7.*, status: unaffected, versionType: custom
version: 6.8, lessThanOrEqual: *, status: unaffected, versionType: original_commit_for_fix
}
