Bug 2357132 (CVE-2025-21996)

Summary: CVE-2025-21996 kernel: drm/radeon: fix uninitialized size issue in radeon_vce_cs_parse()
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: low Docs Contact:
Priority: low    
Version: unspecifiedCC: dfreiber, drow, jburrell, vkumar
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard:
Fixed In Version: Doc Type: ---
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:

Description OSIDB Bzimport 2025-04-03 08:01:16 UTC 
In the Linux kernel, the following vulnerability has been resolved:

drm/radeon: fix uninitialized size issue in radeon_vce_cs_parse()

On the off chance that command stream passed from userspace via
ioctl() call to radeon_vce_cs_parse() is weirdly crafted and
first command to execute is to encode (case 0x03000001), the function
in question will attempt to call radeon_vce_cs_reloc() with size
argument that has not been properly initialized. Specifically, 'size'
will point to 'tmp' variable before the latter had a chance to be
assigned any value.

Play it safe and init 'tmp' with 0, thus ensuring that
radeon_vce_cs_reloc() will catch an early error in cases like these.

Found by Linux Verification Center (linuxtesting.org) with static
analysis tool SVACE.

(cherry picked from commit 2d52de55f9ee7aaee0e09ac443f77855989c6b68)
Comment 1 Avinash Hanwate 2025-04-03 10:01:48 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2025040348-CVE-2025-21996-8e4a@gregkh/T