CVE-2024-44969 in Linux
Summary
by MITRE • 09/04/2024
In the Linux kernel, the following vulnerability has been resolved:
s390/sclp: Prevent release of buffer in I/O
When a task waiting for completion of a Store Data operation is interrupted, an attempt is made to halt this operation. If this attempt fails due to a hardware or firmware problem, there is a chance that the SCLP facility might store data into buffers referenced by the original operation at a later time.
Handle this situation by not releasing the referenced data buffers if the halt attempt fails. For current use cases, this might result in a leak of few pages of memory in case of a rare hardware/firmware malfunction.
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Analysis
by VulDB Data Team • 10/11/2024
The vulnerability CVE-2024-44969 resides within the Linux kernel's s390 architecture implementation, specifically affecting the SCLP (Service Call Logical Processor) subsystem. This flaw manifests in the handling of Store Data operations, which are critical for system communication and data management on IBM z/Architecture systems. The SCLP facility serves as a communication interface between the operating system and hardware for various system management tasks including logging, configuration changes, and system information retrieval. When a task initiates a Store Data operation and subsequently becomes interrupted, the kernel attempts to halt this ongoing operation to prevent potential system instability or data corruption.
The technical root cause of this vulnerability stems from improper buffer management during the interruption process of SCLP operations. When an interruption occurs during a Store Data operation, the kernel attempts to halt the operation through specific hardware mechanisms. However, if this halt mechanism fails due to underlying hardware or firmware problems, the system enters an inconsistent state where the SCLP facility might continue writing data to memory buffers that were already intended for release. This creates a scenario where memory that should have been freed remains accessible and potentially contains stale data from previous operations, leading to memory corruption or information leakage. The vulnerability specifically affects the buffer release logic that determines whether to free memory resources when operation halting fails.
The operational impact of this vulnerability extends beyond simple memory management issues, as it represents a potential security risk in systems where memory integrity is critical. The memory leak, while limited to a few pages of memory in most cases, could provide an attacker with access to previously freed memory regions that might contain sensitive data or system information. This vulnerability particularly affects IBM z/Architecture systems running Linux kernels with SCLP support, making it relevant to enterprise computing environments that rely on mainframe technology for critical operations. The rare occurrence of hardware or firmware malfunctions that trigger this condition means the vulnerability may not manifest frequently, but its potential for causing memory corruption makes it significant for system stability and security.
Mitigation strategies for this vulnerability focus on ensuring proper buffer handling and memory management during SCLP operation interruptions. System administrators should apply the latest kernel updates that contain the patched code addressing the buffer release logic. The fix implemented prevents the release of referenced data buffers when the halt attempt fails, thereby avoiding potential memory corruption scenarios. Organizations running affected systems should also consider implementing monitoring solutions to detect unusual memory usage patterns that might indicate the vulnerability's exploitation. The mitigation aligns with common security practices outlined in CWE-404, which addresses improper resource release, and follows ATT&CK techniques related to privilege escalation and resource exhaustion. Regular system updates and proper patch management remain the most effective defense against this class of vulnerabilities, particularly in enterprise environments where system stability and data integrity are paramount considerations.