title: drm/mediatek: hdmi: Perform NULL pointer check for mtk_hdmi_conf
description: In the Linux kernel, the following vulnerability has been resolved:
drm/mediatek: hdmi: Perform NULL pointer check for mtk_hdmi_conf
In commit 41ca9caaae0b
("drm/mediatek: hdmi: Add check for CEA modes only") a check
for CEA modes was added to function mtk_hdmi_bridge_mode_valid()
in order to address possible issues on MT8167;
moreover, with commit c91026a938c2
("drm/mediatek: hdmi: Add optional limit on maximal HDMI mode clock")
another similar check was introduced.
Unfortunately though, at the time of writing, MT8173 does not provide
any mtk_hdmi_conf structure and this is crashing the kernel with NULL
pointer upon entering mtk_hdmi_bridge_mode_valid(), which happens as
soon as a HDMI cable gets plugged in.
To fix this regression, add a NULL pointer check for hdmi->conf in the
said function, restoring HDMI functionality and avoiding NULL pointer
kernel panics.
affected:
{
product: Linux
vendor: Linux
defaultStatus: unaffected
repo: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
versions:
version: 41ca9caaae0b, lessThan: 71d07ebc5000, status: affected, versionType: git
version: 41ca9caaae0b, lessThan: 3b8e19a0aa39, 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: 5.14, status: affected
version: 0, lessThan: 5.14, status: unaffected, versionType: custom
version: 5.15.12, lessThanOrEqual: 5.15.*, status: unaffected, versionType: custom
version: 5.16, lessThanOrEqual: *, status: unaffected, versionType: original_commit_for_fix
}
