Bug 2315218 (CVE-2024-46866)

Summary: CVE-2024-46866 kernel: drm/xe/client: add missing bo locking in show_meminfo()
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
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A vulnerability in the Linux kernel's `drm/xe/client` driver was resolved. This issue was resolved by adding the missing buffer object (BO) locking in the `show_meminfo()` function. Inspecting the BO state without this lock led to a NULL pointer dereference (NPD) or use-after-free (UAF) issues due to concurrent state changes.
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Bug Depends On: 2315237    
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Description OSIDB Bzimport 2024-09-27 13:23:32 UTC 
In the Linux kernel, the following vulnerability has been resolved:

drm/xe/client: add missing bo locking in show_meminfo()

bo_meminfo() wants to inspect bo state like tt and the ttm resource,
however this state can change at any point leading to stuff like NPD and
UAF, if the bo lock is not held. Grab the bo lock when calling
bo_meminfo(), ensuring we drop any spinlocks first. In the case of
object_idr we now also need to hold a ref.

v2 (MattB)
  - Also add xe_bo_assert_held()

(cherry picked from commit 4f63d712fa104c3ebefcb289d1e733e86d8698c7)
Comment 1 Robb Gatica 2024-09-27 14:23:58 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2024092746-CVE-2024-46866-c414@gregkh/T