linux-cve-announce - CVE-2025-40148: drm/amd/display: Add NULL pointer checks in dc

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Message-ID: <2025111257-CVE-2025-40148-eef5@gregkh>
Date: Wed, 12 Nov 2025 19:24:24 +0900
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...nel.org>
Subject: CVE-2025-40148: drm/amd/display: Add NULL pointer checks in dc_stream cursor attribute functions

From: Greg Kroah-Hartman <gregkh@...nel.org>

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

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

drm/amd/display: Add NULL pointer checks in dc_stream cursor attribute functions

The function dc_stream_set_cursor_attributes() currently dereferences
the `stream` pointer and nested members `stream->ctx->dc->current_state`
without checking for NULL.

All callers of these functions, such as in
`dcn30_apply_idle_power_optimizations()` and
`amdgpu_dm_plane_handle_cursor_update()`, already perform NULL checks
before calling these functions.

Fixes below:
drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_stream.c:336 dc_stream_program_cursor_attributes()
error: we previously assumed 'stream' could be null (see line 334)

drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_stream.c
    327 bool dc_stream_program_cursor_attributes(
    328         struct dc_stream_state *stream,
    329         const struct dc_cursor_attributes *attributes)
    330 {
    331         struct dc  *dc;
    332         bool reset_idle_optimizations = false;
    333
    334         dc = stream ? stream->ctx->dc : NULL;
                     ^^^^^^
The old code assumed stream could be NULL.

    335
--> 336         if (dc_stream_set_cursor_attributes(stream, attributes)) {
                                                    ^^^^^^
The refactor added an unchecked dereference.

drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_stream.c
   313  bool dc_stream_set_cursor_attributes(
   314          struct dc_stream_state *stream,
   315          const struct dc_cursor_attributes *attributes)
   316  {
   317          bool result = false;
   318
   319          if (dc_stream_check_cursor_attributes(stream, stream->ctx->dc->current_state, attributes)) {
                                                              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Here.
This function used to check for if stream as NULL and return false at
the start. Probably we should add that back.

The Linux kernel CVE team has assigned CVE-2025-40148 to this issue.


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

	Issue introduced in 6.16 with commit 4465dd0e41e8223a46a41ce4fcdfc55fabd319d8 and fixed in 6.17.3 with commit 01e793e7d4d402c473f1a61ca5824f086693be65
	Issue introduced in 6.16 with commit 4465dd0e41e8223a46a41ce4fcdfc55fabd319d8 and fixed in 6.18-rc1 with commit bf4e4b97d0fdc66f04fc19d807e24dd8421b8f11

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-2025-40148
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/dc/core/dc_stream.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/01e793e7d4d402c473f1a61ca5824f086693be65
	https://git.kernel.org/stable/c/bf4e4b97d0fdc66f04fc19d807e24dd8421b8f11