CVE-2024-44978 in Linux
Summary
by MITRE • 09/04/2024
In the Linux kernel, the following vulnerability has been resolved:
drm/xe: Free job before xe_exec_queue_put
Free job depends on job->vm being valid, the last xe_exec_queue_put can destroy the VM. Prevent UAF by freeing job before xe_exec_queue_put.
(cherry picked from commit 32a42c93b74c8ca6d0915ea3eba21bceff53042f)
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Analysis
by VulDB Data Team • 12/13/2024
This vulnerability exists within the Linux kernel's graphics subsystem, specifically in the x86 graphics execution driver component known as drm/xe. The flaw manifests as a use-after-free condition that occurs during the processing of graphics execution jobs within the kernel's graphics execution queue management system. The vulnerability stems from improper ordering of resource cleanup operations during job processing, creating a scenario where a job structure may be accessed after its memory has been freed, leading to potential system instability or exploitation.
The technical implementation of this vulnerability involves the drm/xe driver's handling of graphics execution jobs and their associated virtual memory management structures. When processing graphics execution jobs, the driver performs operations that depend on job->vm being a valid pointer reference. However, the current implementation fails to properly sequence the cleanup operations, allowing xe_exec_queue_put to be called before job->vm is freed. This creates a situation where job->vm may be destroyed while the job structure is still being referenced, resulting in a use-after-free condition that can be exploited by malicious actors to gain unauthorized access to system resources.
The operational impact of this vulnerability extends beyond simple system crashes, potentially enabling privilege escalation attacks and arbitrary code execution within the kernel space. When the use-after-free condition occurs, attackers can manipulate the memory layout to redirect execution flow or corrupt kernel data structures, leading to complete system compromise. This vulnerability affects systems running Linux kernel versions that include the affected drm/xe driver components and represents a critical security risk for graphics-intensive applications and systems where kernel-level privileges are required.
Mitigation strategies should focus on immediate patch application to address the specific ordering issue in the xe_exec_queue_put function call sequence. The fix implemented in the kernel resolves the vulnerability by ensuring that job structures are freed before xe_exec_queue_put is invoked, preventing the access to freed memory. Additionally, system administrators should implement monitoring for unusual graphics processing behavior and maintain up-to-date kernel versions that contain the patched drm/xe driver components. The vulnerability aligns with CWE-416, which addresses use-after-free conditions in software systems, and could potentially be leveraged through ATT&CK techniques targeting kernel exploits and privilege escalation within the system's graphics processing subsystem.
The fix demonstrates proper resource management practices by ensuring that object lifecycles are properly sequenced during cleanup operations. This approach prevents the scenario where dependent objects are accessed after their parent resources have been released, which is a fundamental principle in secure programming and memory management within kernel space. The cherry-pick of commit 32a42c93b74c8ca6d0915ea3eba21bceff53042f indicates that this was a targeted fix addressing a specific ordering issue that had been identified and resolved in the kernel development cycle.