CVE-2021-47108

Summary

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 Software

VendorProductVersion RangeStatus
LinuxLinux41ca9caaae0bfc959b22dbcd59d88a7107707e17 < 71d07ebc5000b9c1d140e99e7493b0bafa954776affected
LinuxLinux41ca9caaae0bfc959b22dbcd59d88a7107707e17 < 3b8e19a0aa3933a785be9f1541afd8d398c4ec69affected
LinuxLinux5.14affected
LinuxLinux0 < 5.14unaffected
LinuxLinux5.15.12 <= 5.15.*unaffected
LinuxLinux5.16 <= *unaffected

Weaknesses

ADP Enrichment

CISA ADP Vulnrichment

  • SSVC:
  • Exploitation: none
    • Automatable: no
    • Technical Impact: partial

CVE Program Container

Additional References

References