CVE-2022-49218

/// Technical description

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

drm/dp: Fix OOB read when handling Post Cursor2 register

The link_status array was not large enough to read the Adjust Request

Post Cursor2 register, so remove the common helper function to avoid

an OOB read, found with a -Warray-bounds build:

drivers/gpu/drm/drm_dp_helper.c: In function 'drm_dp_get_adjust_request_post_cursor':

drivers/gpu/drm/drm_dp_helper.c:59:27: error: array subscript 10 is outside array bounds of 'const u8[6]' {aka 'const unsigned char[6]'} [-Werror=array-bounds]

59 | return link_status[r - DP_LANE0_1_STATUS];

| ~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~

drivers/gpu/drm/drm_dp_helper.c:147:51: note: while referencing 'link_status'

147 | u8 drm_dp_get_adjust_request_post_cursor(const u8 link_status[DP_LINK_STATUS_SIZE],

| ~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Replace the only user of the helper with an open-coded fetch

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References