CVE-2024-26799 in Linux
Summary
by MITRE • 04/04/2024
In the Linux kernel, the following vulnerability has been resolved:
ASoC: qcom: Fix uninitialized pointer dmactl
In the case where __lpass_get_dmactl_handle is called and the driver id dai_id is invalid the pointer dmactl is not being assigned a value, and dmactl contains a garbage value since it has not been initialized and so the null check may not work. Fix this to initialize dmactl to NULL. One could argue that modern compilers will set this to zero, but it is useful to keep this initialized as per the same way in functions __lpass_platform_codec_intf_init and lpass_cdc_dma_daiops_hw_params.
Cleans up clang scan build warning: sound/soc/qcom/lpass-cdc-dma.c:275:7: warning: Branch condition evaluates to a garbage value [core.uninitialized.Branch]
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Analysis
by VulDB Data Team • 08/04/2025
The vulnerability CVE-2024-26799 represents an uninitialized pointer issue within the Linux kernel's audio subsystem, specifically affecting the Qualcomm Low Power Audio Subsystem (ASoC) driver. This flaw exists in the lpass-cdc-dma.c file where the function __lpass_get_dmactl_handle fails to properly initialize the dmactl pointer variable when handling invalid DAI (Digital Audio Interface) identifiers. The root cause stems from the absence of explicit initialization for the dmactl pointer, which results in it containing garbage values from the stack memory. This uninitialized state creates a potential security risk as the subsequent null check may fail to properly validate the pointer's validity, allowing for unpredictable behavior and potential exploitation vectors within the audio processing pipeline.
The technical implementation flaw manifests when the driver encounters invalid dai_id values during the __lpass_get_dmactl_handle function call. The dmactl pointer remains uninitialized in error paths, meaning it retains whatever arbitrary value was previously stored in that memory location. This uninitialized pointer condition directly violates the principles outlined in CWE-457: Use of Uninitialized Variable, which specifically addresses scenarios where variables are used without proper initialization. The clang static analysis tool identifies this as a core uninitialized branch condition warning, indicating that the compiler's analysis engine detects the potential for garbage values to influence conditional logic execution paths. This particular vulnerability operates at the kernel level within the sound subsystem, making it particularly dangerous as it could potentially be exploited to manipulate audio processing operations or gain unauthorized access to kernel memory regions.
The operational impact of this vulnerability extends beyond simple code quality issues to potentially compromise system security and stability within embedded audio processing environments. When the dmactl pointer contains garbage values instead of NULL, the audio driver may attempt to dereference invalid memory locations or execute incorrect control operations, leading to system instability, audio processing failures, or in worst-case scenarios, privilege escalation opportunities. The vulnerability affects Qualcomm-based audio subsystems that utilize the LPASS (Low Power Audio Subsystem) architecture, which is commonly found in mobile devices, automotive infotainment systems, and IoT devices where audio processing is critical. Attackers could potentially exploit this uninitialized pointer to manipulate audio DMA (Direct Memory Access) control structures, potentially leading to denial of service conditions or unauthorized access to audio processing resources.
The recommended mitigation strategy involves explicitly initializing the dmactl pointer to NULL within the __lpass_get_dmactl_handle function before any conditional logic is executed. This approach aligns with established kernel coding practices and maintains consistency with similar initialization patterns found in other functions within the same codebase such as __lpass_platform_codec_intf_init and lpass_cdc_dma_daiops_hw_params. The fix ensures that all code paths properly initialize the pointer variable, eliminating the potential for garbage values to influence program flow and maintaining predictable behavior in error conditions. Additionally, this remediation addresses the clang scan build warning by ensuring that branch conditions evaluate based on properly initialized values rather than potentially corrupted memory contents. System administrators should apply the kernel patch that implements this fix as part of their regular security maintenance procedures, particularly in environments where audio processing stability and security are critical requirements. The solution follows the ATT&CK framework's principle of defensive coding practices by ensuring proper variable initialization and preventing potential exploitation of uninitialized memory access patterns.