Bug 2320466 (CVE-2024-49970)

Summary: CVE-2024-49970 kernel: drm/amd/display: Implement bounds check for stream encoder creation in DCN401
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
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Priority: medium    
Version: unspecifiedCC: dfreiber, drow, jburrell, vkumar
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Hardware: All   
OS: Linux   
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Bug Depends On: 2320804    
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Description OSIDB Bzimport 2024-10-21 19:03:53 UTC 
In the Linux kernel, the following vulnerability has been resolved:

drm/amd/display: Implement bounds check for stream encoder creation in DCN401

'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 dcn401_stream_encoder_create

Found by smatch:
drivers/gpu/drm/amd/amdgpu/../display/dc/resource/dcn401/dcn401_resource.c:1209 dcn401_stream_encoder_create() error: buffer overflow 'stream_enc_regs' 4 <= 5
Comment 1 Robb Gatica 2024-10-21 22:24:28 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2024102133-CVE-2024-49970-a345@gregkh/T