[SRU][J][PATCH 0/1] CVE-2024-56608

[Massimiliano Pellizzer]

https://ubuntu.com/security/CVE-2024-56608

[ Impact ]

drm/amd/display: Fix out-of-bounds access in 'dcn21_link_encoder_create'

An issue was identified in the dcn21_link_encoder_create function where
an out-of-bounds access could occur when the hpd_source index was used
to reference the link_enc_hpd_regs array. This array has a fixed size
and the index was not being checked against the array's bounds before
accessing it.

This fix adds a conditional check to ensure that the hpd_source index is
within the valid range of the link_enc_hpd_regs array. If the index is
out of bounds, the function now returns NULL to prevent undefined
behavior.

[ Fix ]

Oracular: Fixed via upstream stable updates (LP: #2096827)
Noble: Fixed via upstream stable updates (LP: #2102118)
Jammy: Cherry picked from mainline
Focal: Not affected

[ Test Plan ]

Compiled tested only.

[ Where Problems Could Occur ]

A regression here is unlikely due to the very limited scope
of the patch.