Subject: CVE-2024-26660: drm/amd/display: Implement bounds check for stream encoder creation in DCN301

From: Greg Kroah-Hartman <[email-masked]>

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

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

drm/amd/display: Implement bounds check for stream encoder creation in DCN301

'stream_enc_regs' array is an array of dcn10_stream_enc_registers
structures. The array is initialized with four elements, corresponding
to the four calls to stream_enc_regs() in the array initializer. This
means that valid indices for this array are 0, 1, 2, and 3.

The error message 'stream_enc_regs' 4 <= 5 below, is indicating that
there is an attempt to access this array with an index of 5, which is
out of bounds. This could lead to undefined behavior

Here, eng_id is used as an index to access the stream_enc_regs array. If
eng_id is 5, this would result in an out-of-bounds access on the
stream_enc_regs array.

Thus fixing Buffer overflow error in dcn301_stream_encoder_create
reported by Smatch:
drivers/gpu/drm/amd/amdgpu/../display/dc/resource/dcn301/dcn301_resource.c:1011 dcn301_stream_encoder_create() error: buffer overflow 'stream_enc_regs' 4 <= 5

The Linux kernel CVE team has assigned CVE-2024-26660 to this issue.

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

	Issue introduced in 5.11 with commit 3a83e4e64bb1 and fixed in 5.15.149 with commit 42442f74314d
	Issue introduced in 5.11 with commit 3a83e4e64bb1 and fixed in 6.1.78 with commit efdd665ce1a1
	Issue introduced in 5.11 with commit 3a83e4e64bb1 and fixed in 6.6.17 with commit cd9bd10c59e3
	Issue introduced in 5.11 with commit 3a83e4e64bb1 and fixed in 6.7.5 with commit a938eab9586e
	Issue introduced in 5.11 with commit 3a83e4e64bb1 and fixed in 6.8 with commit 58fca355ad37

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-2024-26660
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/resource/dcn301/dcn301_resource.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/42442f74314d41ddc68227047036fa3e78940054
	https://git.kernel.org/stable/c/efdd665ce1a1634b8c1dad5e7f6baaef3e131d0a
	https://git.kernel.org/stable/c/cd9bd10c59e3c1446680514fd3097c5b00d3712d
	https://git.kernel.org/stable/c/a938eab9586eea31cfd129a507f552efae14d738
	https://git.kernel.org/stable/c/58fca355ad37dcb5f785d9095db5f748b79c5dc2