CVE-2024-56608

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

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.

References:

[ 65.920507] ------------[ cut here ]------------ [ 65.920510] UBSAN: array-index-out-of-bounds in drivers/gpu/drm/amd/amdgpu/../display/dc/resource/dcn21/dcn21_resource.c:1312:29 [ 65.920519] index 7 is out of range for type 'dcn10_link_enc_hpd_registers [5]' [ 65.920523] CPU: 3 PID: 1178 Comm: modprobe Tainted: G OE 6.8.0-cleanershaderfeatureresetasdntipmi200nv2132 #13 [ 65.920525] Hardware name: AMD Majolica-RN/Majolica-RN, BIOS WMJ0429N_Weekly_20_04_2 04/29/2020 [ 65.920527] Call Trace: [ 65.920529] <TASK> [ 65.920532] dump_stack_lvl+0x48/0x70 [ 65.920541] dump_stack+0x10/0x20 [ 65.920543] __ubsan_handle_out_of_bounds+0xa2/0xe0 [ 65.920549] dcn21_link_encoder_create+0xd9/0x140 [amdgpu] [ 65.921009] link_create+0x6d3/0xed0 [amdgpu] [ 65.921355] create_links+0x18a/0x4e0 [amdgpu] [ 65.921679] dc_create+0x360/0x720 [amdgpu] [ 65.921999] ? dmi_matches+0xa0/0x220 [ 65.922004] amdgpu_dm_init+0x2b6/0x2c90 [amdgpu] [ 65.922342] ? console_unlock+0x77/0x120 [ 65.922348] ? dev_printk_emit+0x86/0xb0 [ 65.922354] dm_hw_init+0x15/0x40 [amdgpu] [ 65.922686] amdgpu_device_init+0x26a8/0x33a0 [amdgpu] [ 65.922921] amdgpu_driver_load_kms+0x1b/0xa0 [amdgpu] [ 65.923087] amdgpu_pci_probe+0x1b7/0x630 [amdgpu] [ 65.923087]...