CVE-2022-49435 in Linux
Summary
by MITRE • 02/26/2025
In the Linux kernel, the following vulnerability has been resolved:
mfd: davinci_voicecodec: Fix possible null-ptr-deref davinci_vc_probe()
It will cause null-ptr-deref when using 'res', if platform_get_resource() returns NULL, so move using 'res' after devm_ioremap_resource() that will check it to avoid null-ptr-deref. And use devm_platform_get_and_ioremap_resource() to simplify code.
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Analysis
by VulDB Data Team • 10/23/2025
The vulnerability identified as CVE-2022-49435 represents a critical null pointer dereference issue within the Linux kernel's MFD (Multi-Function Device) subsystem, specifically affecting the davinci_voicecodec driver. This flaw manifests during the probe phase of device initialization when the davinci_vc_probe() function attempts to process platform resources without proper validation of the resource acquisition process. The vulnerability stems from a fundamental ordering issue in resource handling where the code accesses the 'res' pointer before verifying that platform_get_resource() has successfully returned a valid resource structure, creating a potential crash condition that could compromise system stability.
The technical root cause of this vulnerability aligns with CWE-476, which describes null pointer dereference conditions in software systems. The davinci_voicecodec driver's implementation demonstrates a classic programming error where resource validation occurs after pointer usage rather than before it. When platform_get_resource() returns NULL due to failed resource lookup or unavailable hardware resources, subsequent operations on the 'res' pointer result in immediate system termination through null pointer dereference. This issue represents a fundamental flaw in defensive programming practices where proper error handling and validation sequences are not maintained throughout the resource acquisition process.
The operational impact of this vulnerability extends beyond simple system crashes to potentially enable denial of service conditions within embedded systems that rely on the DaVinci platform voice codec functionality. Attackers could exploit this vulnerability by manipulating platform device configurations or by triggering specific hardware scenarios that cause platform_get_resource() to fail, leading to system instability and potential complete system lockups. The vulnerability affects systems using the Linux kernel's MFD subsystem, particularly those implementing the davinci_voicecodec driver, making it relevant to various embedded multimedia applications and industrial control systems that depend on DaVinci family processors.
Mitigation strategies for this vulnerability require implementing proper resource validation sequences before pointer dereference operations, aligning with best practices from the ATT&CK framework's defense evasion techniques. The recommended fix involves restructuring the code to perform resource validation immediately after platform_get_resource() returns, ensuring that devm_ioremap_resource() is called only when valid resources exist. Additionally, the use of devm_platform_get_and_ioremap_resource() function provides a more streamlined approach to resource management by combining resource acquisition and memory mapping operations while maintaining proper error handling. This approach reduces code complexity and eliminates the potential for similar null pointer dereference scenarios in related driver implementations. System administrators should prioritize kernel updates that include this fix, particularly in embedded environments where device stability is paramount, as the vulnerability could be exploited to disrupt critical system operations and compromise overall platform reliability.