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National Vulnerability Database

National Vulnerability Database

NVD

National Vulnerability Database

Vulnerability Change Records for CVE-2021-47200

Change History

New CVE Received by NIST 4/10/2024 3:15:48 PM

Action Type Old Value New Value
Added Description 

								
							
							
								
							
						
								
							
								
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."

								
								
					

					

						Added
						Reference
						
							
							
								
							
								

								
							
							
								
							
						
								
							
								
kernel.org https://git.kernel.org/stable/c/4f8e469a2384dfa4047145b0093126462cbb6dc0 [No types assigned]

								
								
					

					

						Added
						Reference
						
							
							
								
							
								

								
							
							
								
							
						
								
							
								
kernel.org https://git.kernel.org/stable/c/8244a3bc27b3efd057da154b8d7e414670d5044f [No types assigned]