CVE-2021-47200 (GCVE-0-2021-47200)

Vulnerability from cvelistv5 – Published: 2024-04-10 18:56 – Updated: 2025-05-04 07:06
VLAI?
Title
drm/prime: Fix use after free in mmap with drm_gem_ttm_mmap
Summary
In the Linux kernel, the following vulnerability has been resolved: drm/prime: Fix use after free in mmap with drm_gem_ttm_mmap drm_gem_ttm_mmap() drops a reference to the gem object on success. If the gem object's refcount == 1 on entry to drm_gem_prime_mmap(), that drop will free the gem object, and the subsequent drm_gem_object_get() will be a UAF. Fix by grabbing a reference before calling the mmap helper. This issue was forseen when the reference dropping was adding in commit 9786b65bc61ac ("drm/ttm: fix mmap refcounting"): "For that to work properly the drm_gem_object_get() call in drm_gem_ttm_mmap() must be moved so it happens before calling obj->funcs->mmap(), otherwise the gem refcount would go down to zero."
Severity ?
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: 9786b65bc61acec63f923978c75e707afbb74bc7 , < 4f8e469a2384dfa4047145b0093126462cbb6dc0 (git)
Affected: 9786b65bc61acec63f923978c75e707afbb74bc7 , < 8244a3bc27b3efd057da154b8d7e414670d5044f (git)
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    Linux Linux Affected: 5.5
Unaffected: 0 , < 5.5 (semver)
Unaffected: 5.15.5 , ≤ 5.15.* (semver)
Unaffected: 5.16 , ≤ * (original_commit_for_fix)
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