CVE-2022-49832 in Linux
Summary
by MITRE • 05/01/2025
In the Linux kernel, the following vulnerability has been resolved:
pinctrl: devicetree: fix null pointer dereferencing in pinctrl_dt_to_map
Here is the BUG report by KASAN about null pointer dereference:
BUG: KASAN: null-ptr-deref in strcmp+0x2e/0x50 Read of size 1 at addr 0000000000000000 by task python3/2640 Call Trace: strcmp __of_find_property of_find_property pinctrl_dt_to_map
kasprintf() would return NULL pointer when kmalloc() fail to allocate. So directly return ENOMEM, if kasprintf() return NULL pointer.
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Analysis
by VulDB Data Team • 11/10/2025
The vulnerability CVE-2022-49832 represents a critical null pointer dereference issue within the Linux kernel's pin control subsystem, specifically in the device tree parsing functionality. This flaw exists in the pinctrl_dt_to_map function which processes device tree properties for pin configuration. The vulnerability manifests when the kernel attempts to parse pin control configurations from device tree entries, creating a scenario where a null pointer dereference can occur during string comparison operations. The issue is particularly dangerous because it can be triggered during normal kernel operation when processing device tree data, potentially leading to system instability or denial of service conditions.
The technical root cause of this vulnerability stems from improper error handling in memory allocation operations within the device tree parsing code path. When the kasprintf() function fails to allocate memory due to system resource constraints, it returns a NULL pointer. However, the existing code does not properly check for this NULL return value before proceeding with operations that assume valid memory allocation. The call trace reveals that the error occurs during strcmp() execution, which attempts to dereference a null pointer that was returned by kasprintf() when memory allocation failed. This particular pattern aligns with CWE-476 which describes null pointer dereference vulnerabilities, and specifically demonstrates how inadequate error handling can lead to system crashes and potential exploitation scenarios.
The operational impact of this vulnerability extends beyond simple system crashes, as it can affect the kernel's ability to properly configure hardware pin states during system initialization or runtime operations. When triggered, the null pointer dereference causes immediate kernel panic or system lockup, preventing normal system operation and potentially leading to complete system failure. This vulnerability affects any Linux system running kernel versions where the pinctrl subsystem processes device tree configurations, particularly impacting embedded systems, servers, and devices that rely heavily on device tree based hardware configuration. The vulnerability is especially concerning in environments where resource constraints are common, as the memory allocation failure that triggers the bug is more likely to occur under such conditions.
Mitigation strategies for CVE-2022-49832 should focus on immediate kernel updates to patched versions that properly handle the NULL return values from memory allocation functions. System administrators should prioritize applying security patches from their respective kernel maintainers, as the fix involves adding proper error checking for kasprintf() return values before proceeding with string operations. Additionally, monitoring systems should be configured to detect potential memory allocation failures that could precede this vulnerability, though such detection is limited since the actual vulnerability occurs in the error handling path itself. The fix implementation follows standard security best practices by ensuring all memory allocation functions are properly validated before use, preventing the cascade of errors that lead to null pointer dereference conditions. This vulnerability demonstrates the importance of robust error handling in kernel space code and aligns with ATT&CK technique T1499.004 which covers system shutdown/failure manipulation through kernel-level vulnerabilities.