cve/published/2024/CVE-2024-43895.mbox

From bippy-1.2.0 Mon Sep 17 00:00:00 2001
From: Greg Kroah-Hartman <gregkh@kernel.org>
To: <linux-cve-announce@vger.kernel.org>
Reply-to: <cve@kernel.org>, <linux-kernel@vger.kernel.org>
Subject: CVE-2024-43895: drm/amd/display: Skip Recompute DSC Params if no Stream on Link

Description
===========

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

drm/amd/display: Skip Recompute DSC Params if no Stream on Link

[why]
Encounter NULL pointer dereference uner mst + dsc setup.

BUG: kernel NULL pointer dereference, address: 0000000000000008
    PGD 0 P4D 0
    Oops: 0000 [#1] PREEMPT SMP NOPTI
    CPU: 4 PID: 917 Comm: sway Not tainted 6.3.9-arch1-1 #1 124dc55df4f5272ccb409f39ef4872fc2b3376a2
    Hardware name: LENOVO 20NKS01Y00/20NKS01Y00, BIOS R12ET61W(1.31 ) 07/28/2022
    RIP: 0010:drm_dp_atomic_find_time_slots+0x5e/0x260 [drm_display_helper]
    Code: 01 00 00 48 8b 85 60 05 00 00 48 63 80 88 00 00 00 3b 43 28 0f 8d 2e 01 00 00 48 8b 53 30 48 8d 04 80 48 8d 04 c2 48 8b 40 18 <48> 8>
    RSP: 0018:ffff960cc2df77d8 EFLAGS: 00010293
    RAX: 0000000000000000 RBX: ffff8afb87e81280 RCX: 0000000000000224
    RDX: ffff8afb9ee37c00 RSI: ffff8afb8da1a578 RDI: ffff8afb87e81280
    RBP: ffff8afb83d67000 R08: 0000000000000001 R09: ffff8afb9652f850
    R10: ffff960cc2df7908 R11: 0000000000000002 R12: 0000000000000000
    R13: ffff8afb8d7688a0 R14: ffff8afb8da1a578 R15: 0000000000000224
    FS:  00007f4dac35ce00(0000) GS:ffff8afe30b00000(0000) knlGS:0000000000000000
    CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
    CR2: 0000000000000008 CR3: 000000010ddc6000 CR4: 00000000003506e0
    Call Trace:
<TASK>
     ? __die+0x23/0x70
     ? page_fault_oops+0x171/0x4e0
     ? plist_add+0xbe/0x100
     ? exc_page_fault+0x7c/0x180
     ? asm_exc_page_fault+0x26/0x30
     ? drm_dp_atomic_find_time_slots+0x5e/0x260 [drm_display_helper 0e67723696438d8e02b741593dd50d80b44c2026]
     ? drm_dp_atomic_find_time_slots+0x28/0x260 [drm_display_helper 0e67723696438d8e02b741593dd50d80b44c2026]
     compute_mst_dsc_configs_for_link+0x2ff/0xa40 [amdgpu 62e600d2a75e9158e1cd0a243bdc8e6da040c054]
     ? fill_plane_buffer_attributes+0x419/0x510 [amdgpu 62e600d2a75e9158e1cd0a243bdc8e6da040c054]
     compute_mst_dsc_configs_for_state+0x1e1/0x250 [amdgpu 62e600d2a75e9158e1cd0a243bdc8e6da040c054]
     amdgpu_dm_atomic_check+0xecd/0x1190 [amdgpu 62e600d2a75e9158e1cd0a243bdc8e6da040c054]
     drm_atomic_check_only+0x5c5/0xa40
     drm_mode_atomic_ioctl+0x76e/0xbc0

[how]
dsc recompute should be skipped if no mode change detected on the new
request. If detected, keep checking whether the stream is already on
current state or not.

(cherry picked from commit 8151a6c13111b465dbabe07c19f572f7cbd16fef)

The Linux kernel CVE team has assigned CVE-2024-43895 to this issue.


Affected and fixed versions
===========================

	Issue introduced in 5.16 with commit a550bb165b3f9ed92d6c335e1ea191bf28bb4e0f and fixed in 6.1.105 with commit 282f0a482ee61d5e863512f3c4fcec90216c20d9
	Issue introduced in 5.16 with commit a550bb165b3f9ed92d6c335e1ea191bf28bb4e0f and fixed in 6.6.46 with commit 718d83f66fb07b2cab89a1fc984613a00e3db18f
	Issue introduced in 5.16 with commit a550bb165b3f9ed92d6c335e1ea191bf28bb4e0f and fixed in 6.10.5 with commit 70275bb960c71d313254473d38c14e7101cee5ad
	Issue introduced in 5.16 with commit a550bb165b3f9ed92d6c335e1ea191bf28bb4e0f and fixed in 6.11 with commit 50e376f1fe3bf571d0645ddf48ad37eb58323919

Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2024-43895
will be updated if fixes are backported, please check that for the most
up to date information about this issue.


Affected files
==============

The file(s) affected by this issue are:
	drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c


Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/282f0a482ee61d5e863512f3c4fcec90216c20d9
	https://git.kernel.org/stable/c/718d83f66fb07b2cab89a1fc984613a00e3db18f
	https://git.kernel.org/stable/c/70275bb960c71d313254473d38c14e7101cee5ad
	https://git.kernel.org/stable/c/50e376f1fe3bf571d0645ddf48ad37eb58323919