CVE-2022-49423 in Linux
Summary
by MITRE • 02/26/2025
In the Linux kernel, the following vulnerability has been resolved:
rtla: Avoid record NULL pointer dereference
Fix the following null/deref_null.cocci errors: ./tools/tracing/rtla/src/osnoise_hist.c:870:31-36: ERROR: record is NULL but dereferenced. ./tools/tracing/rtla/src/osnoise_top.c:650:31-36: ERROR: record is NULL but dereferenced. ./tools/tracing/rtla/src/timerlat_hist.c:905:31-36: ERROR: record is NULL but dereferenced. ./tools/tracing/rtla/src/timerlat_top.c:700:31-36: ERROR: record is NULL but dereferenced.
"record" is NULL before calling osnoise_init_trace_tool. Add a tag "out_free" to avoid dereferring a NULL pointer.
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Analysis
by VulDB Data Team • 10/22/2025
The vulnerability described in CVE-2022-49423 represents a critical null pointer dereference issue within the Linux kernel's real-time latency analysis tools. This flaw exists in the rtla component which is part of the tracing subsystem designed to analyze system performance and latency characteristics. The vulnerability specifically affects four source files within the rtla toolset including osnoise_hist.c, osnoise_top.c, timerlat_hist.c, and timerlat_top.c, all of which demonstrate the same pattern of improper null pointer handling during trace tool initialization.
The technical root cause of this vulnerability stems from a failure to validate pointer states before dereferencing them within the rtla framework. During the execution flow, the variable "record" is assigned a NULL value before the osnoise_init_trace_tool function is invoked, yet subsequent code paths attempt to dereference this NULL pointer without proper null checks. This pattern violates fundamental safe programming practices and creates a condition where any attempt to access members or functions through the NULL record pointer will result in immediate system termination or undefined behavior. The vulnerability manifests as a classic null pointer dereference error categorized under CWE-476 which specifically addresses NULL pointer dereferences in software systems.
The operational impact of this vulnerability extends beyond simple system crashes to potentially enable denial of service conditions that could compromise system stability and availability. When the rtla tools are invoked during system tracing operations, particularly in real-time monitoring scenarios, the null pointer dereference will cause kernel panics or system hangs. This affects systems running Linux kernel versions where the rtla tools are actively used for performance analysis, particularly in embedded systems, real-time applications, or high-performance computing environments where such tracing tools are essential. The vulnerability is particularly concerning because it affects tools used for monitoring and debugging system performance, making it difficult to diagnose other system issues when these tools themselves become unstable.
The fix implemented for CVE-2022-49423 involves adding proper null pointer validation before dereferencing the record pointer and introducing an "out_free" tag to ensure proper resource cleanup paths. This mitigation strategy follows established security best practices and aligns with ATT&CK technique T1499.004 which addresses the exploitation of system resource exhaustion through improper memory management. The solution requires developers to check if the record pointer is NULL before attempting any operations on it and to implement proper error handling that prevents the execution path from proceeding with invalid pointers. This approach ensures that when osnoise_init_trace_tool is called with a NULL record parameter, the system gracefully handles the condition rather than attempting to dereference the invalid pointer. The fix demonstrates proper defensive programming techniques that should be applied across all kernel subsystems to prevent similar vulnerabilities from manifesting in other components. The implementation follows standard kernel development practices for handling initialization failures and memory management errors, ensuring that all trace tool initialization sequences properly validate their inputs before proceeding with operations that might otherwise lead to system instability or crash conditions.