CVE-2023-52774 in Linux
Summary
by MITRE • 05/21/2024
In the Linux kernel, the following vulnerability has been resolved:
s390/dasd: protect device queue against concurrent access
In dasd_profile_start() the amount of requests on the device queue are counted. The access to the device queue is unprotected against concurrent access. With a lot of parallel I/O, especially with alias devices enabled, the device queue can change while dasd_profile_start() is accessing the queue. In the worst case this leads to a kernel panic due to incorrect pointer accesses.
Fix this by taking the device lock before accessing the queue and counting the requests. Additionally the check for a valid profile data pointer can be done earlier to avoid unnecessary locking in a hot path.
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Analysis
by VulDB Data Team • 09/23/2025
The vulnerability identified as CVE-2023-52774 resides within the Linux kernel's s390/dasd subsystem, specifically affecting the dasd_profile_start() function. This flaw represents a critical concurrency issue that undermines the integrity of device queue operations on IBM System/390 architecture systems. The s390/dasd driver manages direct access storage devices and is essential for storage operations in mainframe environments where multiple I/O requests can be processed simultaneously. The vulnerability manifests when multiple threads or processes attempt to access the device queue concurrently, creating a race condition that can result in catastrophic system failures.
The technical flaw stems from unprotected access to the device queue structure within the dasd_profile_start() function. When this function counts the number of requests currently in the device queue, it fails to acquire the necessary device lock before performing these operations. This unprotected access creates a window where the queue structure can be modified by other concurrent operations while the counting process is in progress. The underlying issue is classified as a concurrency control problem that violates fundamental principles of kernel-level synchronization. According to CWE-362, this represents a Concurrent Execution using Shared Resource vulnerability where multiple threads access shared data structures without proper mutual exclusion mechanisms.
The operational impact of this vulnerability extends beyond simple performance degradation to potentially causing complete system crashes. When parallel I/O operations are intensive, particularly with alias devices enabled, the device queue undergoes frequent modifications. During these operations, if dasd_profile_start() attempts to read the queue state while another process is modifying it, the function may encounter corrupted pointer references or invalid memory access patterns. This scenario can lead to kernel panics, which are unrecoverable system failures that require complete system restarts. The vulnerability is particularly dangerous in enterprise environments where mainframe systems operate continuously under heavy I/O loads, as it can result in unexpected service interruptions and data availability issues.
The fix implemented for CVE-2023-52774 addresses the root cause by introducing proper locking mechanisms around the device queue access operations. The solution requires acquiring the device lock before any queue examination or request counting occurs, ensuring that no other concurrent processes can modify the queue structure during the critical section. Additionally, the patch optimizes the code by moving the validation of profile data pointer checks to an earlier stage, thereby avoiding unnecessary locking operations in performance-critical paths. This optimization aligns with ATT&CK technique T1070.006, which involves the manipulation of system processes to achieve desired outcomes, by ensuring that locking overhead is minimized while maintaining security guarantees. The mitigation strategy follows established kernel development practices for concurrent access protection and adheres to the principle of least privilege in resource management, where system resources are accessed only when necessary and with appropriate synchronization mechanisms in place.