CVE-2021-47200

published 2024-04-10

CVE-2021-47200: 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…

Priority P3 36 high 7.8 CVSS 3.1

AV L AC L PR L UI N S U C H I H A H

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."

Affected

8 ranges

Vendor	Product	Version range	Fixed in
debian	linux	< linux 5.15.5-1 (bookworm)	linux 5.15.5-1 (bookworm)
linux	linux	—	—
linux	linux	>= 9786b65bc61acec63f923978c75e707afbb74bc7 < 4f8e469a2384dfa4047145b0093126462cbb6dc0	4f8e469a2384dfa4047145b0093126462cbb6dc0
linux	linux	>= 9786b65bc61acec63f923978c75e707afbb74bc7 < 8244a3bc27b3efd057da154b8d7e414670d5044f	8244a3bc27b3efd057da154b8d7e414670d5044f
linux	linux_kernel	>= 0 < 5.15.5-1	5.15.5-1
linux	linux_kernel	>= 0 < 5.15.5-1	5.15.5-1
linux	linux_kernel	>= 0 < 5.15.5-1	5.15.5-1
linux	linux_kernel	>= 5.5 < 5.15.5	5.15.5

CVSS provenance

nvd v3.1 7.8 HIGH CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

osv 7.8 HIGH

vendor_debian 7.8 HIGH

vendor_redhat 7.8 HIGH

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