CVE-2024-49894 in Linux
Summary
by MITRE • 10/21/2024
In the Linux kernel, the following vulnerability has been resolved:
drm/amd/display: Fix index out of bounds in degamma hardware format translation
Fixes index out of bounds issue in `cm_helper_translate_curve_to_degamma_hw_format` function. The issue could occur when the index 'i' exceeds the number of transfer function points (TRANSFER_FUNC_POINTS).
The fix adds a check to ensure 'i' is within bounds before accessing the transfer function points. If 'i' is out of bounds the function returns false to indicate an error.
Reported by smatch: drivers/gpu/drm/amd/amdgpu/../display/dc/dcn10/dcn10_cm_common.c:594 cm_helper_translate_curve_to_degamma_hw_format() error: buffer overflow 'output_tf->tf_pts.red' 1025 <= s32max drivers/gpu/drm/amd/amdgpu/../display/dc/dcn10/dcn10_cm_common.c:595 cm_helper_translate_curve_to_degamma_hw_format() error: buffer overflow 'output_tf->tf_pts.green' 1025 <= s32max drivers/gpu/drm/amd/amdgpu/../display/dc/dcn10/dcn10_cm_common.c:596 cm_helper_translate_curve_to_degamma_hw_format() error: buffer overflow 'output_tf->tf_pts.blue' 1025 <= s32max
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Analysis
by VulDB Data Team • 01/19/2026
The vulnerability identified as CVE-2024-49894 resides within the Linux kernel's AMD display driver component, specifically affecting the drm/amd/display subsystem. This issue manifests as an index out of bounds condition during hardware format translation for degamma functionality, representing a critical security flaw that could potentially be exploited to disrupt system operations or escalate privileges. The vulnerability is particularly concerning given the widespread use of AMD graphics hardware in both consumer and enterprise environments where the Linux kernel serves as the foundational operating system layer.
The technical flaw occurs within the `cm_helper_translate_curve_to_degamma_hw_format` function located in the dcn10_cm_common.c source file. This function processes transfer function points for color management operations, but fails to validate array indices before accessing memory locations. The specific issue arises when the loop variable 'i' exceeds the predefined limit of TRANSFER_FUNC_POINTS, which is typically set to 1024 points. When this boundary condition is violated, the function attempts to access memory locations beyond the allocated buffer for red, green, and blue transfer function points, creating a classic buffer overflow scenario. The smatch static analysis tool identified these specific buffer overflow conditions at lines 594-596, highlighting that the access patterns could exceed the maximum signed 32-bit integer value of 1025.
The operational impact of this vulnerability extends beyond simple memory corruption, as it represents a potential vector for privilege escalation and system instability. When the degamma hardware format translation fails due to buffer overflow, it can cause display subsystem crashes, color distortion, or complete display driver failures that may require system reboot to recover. From a cybersecurity perspective, this vulnerability aligns with CWE-129, which addresses "Improper Validation of Array Index," and represents a subset of the broader category of memory safety issues that have historically enabled exploitation through techniques such as heap spraying or return-oriented programming. The vulnerability's presence in the graphics driver component also connects it to ATT&CK technique T1068, which involves exploiting privileges through local system access.
The fix implemented addresses this vulnerability by introducing proper bounds checking before array access operations. The solution adds a validation mechanism that ensures the index 'i' remains within acceptable limits before proceeding with memory operations on the transfer function points. When the index exceeds the valid range, the function returns false to indicate an error condition rather than allowing the buffer overflow to occur. This defensive programming approach prevents the exploitation of the memory corruption while maintaining the function's intended behavior for valid inputs. The mitigation strategy follows established security principles of input validation and boundary checking, which are fundamental to preventing buffer overflow vulnerabilities and aligning with industry best practices for secure software development. The fix demonstrates the importance of static analysis tools like smatch in identifying potential security flaws before they can be exploited in production environments, reinforcing the need for comprehensive code review processes in kernel development.