CVE-2021-47108

published 2024-03-04

CVE-2021-47108: In the Linux kernel, the following vulnerability has been resolved: drm/mediatek: hdmi: Perform NULL pointer check for mtk_hdmi_conf In commit 41ca9caaae0b…

Priority P4 19 medium 5.5 CVSS 3.1

AV L AC L PR L UI N S U C N I N A H

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

9 ranges

Vendor	Product	Version range	Fixed in
debian	linux	< linux 5.15.15-1 (bookworm)	linux 5.15.15-1 (bookworm)
linux	linux	—	—
linux	linux	>= 41ca9caaae0bfc959b22dbcd59d88a7107707e17 < 71d07ebc5000b9c1d140e99e7493b0bafa954776	71d07ebc5000b9c1d140e99e7493b0bafa954776
linux	linux	>= 41ca9caaae0bfc959b22dbcd59d88a7107707e17 < 3b8e19a0aa3933a785be9f1541afd8d398c4ec69	3b8e19a0aa3933a785be9f1541afd8d398c4ec69
linux	linux_kernel	—	—
linux	linux_kernel	>= 0 < 5.15.15-1	5.15.15-1
linux	linux_kernel	>= 0 < 5.15.15-1	5.15.15-1
linux	linux_kernel	>= 0 < 5.15.15-1	5.15.15-1
linux	linux_kernel	>= 5.14 < 5.15.12	5.15.12

CVSS provenance

nvd v3.1 5.5 MEDIUM CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

osv 5.5 MEDIUM

vendor_debian 5.5 MEDIUM

vendor_redhat 5.5 MEDIUM

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CWE-476