CVE-2024-49904 in Linux
Summary
by MITRE • 10/21/2024
In the Linux kernel, the following vulnerability has been resolved:
drm/amdgpu: add list empty check to avoid null pointer issue
Add list empty check to avoid null pointer issues in some corner cases. - list_for_each_entry_safe()
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Analysis
by VulDB Data Team • 12/18/2024
The vulnerability identified as CVE-2024-49904 resides within the Linux kernel's graphics subsystem, specifically affecting the amdgpu driver component that manages AMD graphics hardware. This issue manifests as a potential null pointer dereference condition that could lead to system instability or denial of service scenarios. The flaw occurs during the processing of graphics-related operations where the driver fails to properly validate list structures before attempting to iterate through them. The vulnerability is particularly concerning as it affects the direct rendering manager subsystem which handles graphics operations for applications and desktop environments.
The technical root cause of this vulnerability stems from insufficient validation within the drm/amdgpu driver implementation where the list_for_each_entry_safe() macro is utilized without proper empty list checks. This pattern creates a scenario where the driver attempts to traverse a linked list structure that may be empty or contain null entries, leading to a null pointer dereference when the iteration logic encounters unexpected list states. The vulnerability is classified under CWE-476 as a NULL pointer dereference, which represents a fundamental memory safety issue where program execution attempts to access memory through a null pointer reference. The flaw specifically impacts the graphics processing pipeline where the driver maintains various lists of graphics objects and resources that must be properly validated before access.
The operational impact of this vulnerability extends beyond simple system crashes to potentially enable privilege escalation or denial of service attacks within graphics-intensive applications. When the amdgpu driver processes graphics commands or manages graphics resources, it relies on maintaining valid linked list structures to track various kernel objects. If an attacker can manipulate the graphics processing flow or trigger specific conditions that result in empty lists being processed, the system could experience unexpected behavior ranging from application crashes to complete system hangs. This vulnerability aligns with ATT&CK technique T1059.003 for command and scripting interpreter usage, as exploitation might involve crafting specific graphics workloads that trigger the problematic code path. The impact is particularly severe in multi-user environments or systems running graphics-intensive applications where the driver's stability directly affects overall system availability.
Mitigation strategies for CVE-2024-49904 require immediate patch application from kernel vendors, as the fix involves adding explicit list empty checks before list traversal operations. System administrators should prioritize updating their Linux kernel versions to include the patched amdgpu driver components that implement proper validation logic for list structures. The recommended approach involves implementing defensive programming practices that validate data structures before processing, specifically checking whether lists are empty or contain valid entries before invoking list_for_each_entry_safe() macros. Organizations should also consider implementing monitoring solutions that can detect unusual graphics processing patterns that might indicate exploitation attempts, while maintaining regular kernel update schedules to address similar vulnerabilities. The fix demonstrates proper secure coding practices as outlined in CERT Secure Coding Standards, where defensive programming techniques such as input validation and null pointer checks are essential for preventing memory safety vulnerabilities in kernel space operations.