CVE-2022-49288 in Linux
Summary
by MITRE • 02/26/2025
In the Linux kernel, the following vulnerability has been resolved:
ALSA: pcm: Fix races among concurrent prealloc proc writes
We have no protection against concurrent PCM buffer preallocation changes via proc files, and it may potentially lead to UAF or some weird problem. This patch applies the PCM open_mutex to the proc write operation for avoiding the racy proc writes and the PCM stream open (and further operations).
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Analysis
by VulDB Data Team • 02/26/2025
The vulnerability identified as CVE-2022-49288 resides within the Linux kernel's Advanced Linux Sound Architecture implementation, specifically affecting the PCM (Pulse Code Modulation) subsystem's handling of concurrent buffer preallocation operations through proc filesystem interfaces. This flaw represents a race condition that can occur when multiple processes attempt to modify PCM buffer preallocation settings simultaneously via proc file operations, creating potential for unpredictable system behavior and security implications.
The technical root cause stems from inadequate synchronization mechanisms within the ALSA PCM subsystem where concurrent modifications to preallocated buffer settings through proc files lack proper protective measures. The absence of appropriate locking mechanisms means that when multiple processes attempt to write to the same PCM buffer preallocation proc interface simultaneously, the system can experience inconsistent state transitions and memory management issues. This particular vulnerability manifests as a lack of protection against concurrent PCM buffer preallocation changes, which can result in use-after-free conditions or other memory corruption scenarios that may be exploited by malicious actors.
The operational impact of this vulnerability extends beyond simple system instability to potentially enable privilege escalation or denial of service conditions within systems relying heavily on audio processing capabilities. When concurrent access occurs during PCM buffer preallocation modifications, the kernel's memory management can become corrupted, leading to unpredictable behavior that might allow attackers to execute arbitrary code with kernel privileges. Systems running kernel versions affected by this vulnerability and utilizing ALSA PCM functionality are particularly at risk, especially in multi-user environments or when audio applications are frequently launched and terminated.
The fix implemented for CVE-2022-49288 addresses this issue by applying the existing PCM open_mutex to the proc write operations for preallocation changes, ensuring that all modifications to PCM buffer preallocation settings occur in a synchronized manner. This approach aligns with established security practices for protecting shared resources in kernel space and prevents the race conditions that could lead to memory corruption. The mitigation strategy follows fundamental principles of concurrent programming and memory safety, similar to those recommended in CWE-362 (Concurrent Execution using Shared Resource with Improper Synchronization) and addresses patterns commonly exploited in kernel-level attacks categorized under MITRE ATT&CK techniques related to privilege escalation and system compromise.
Systems administrators should prioritize updating their kernel versions to include the patch addressing CVE-2022-49288, particularly in environments where audio processing is critical or where multiple concurrent audio applications might be running simultaneously. The vulnerability represents a significant risk in embedded systems, servers, or any environment where audio subsystems are actively used and where concurrent access patterns might occur. Regular kernel updates and security monitoring are essential to maintain system integrity and prevent exploitation of this and similar race condition vulnerabilities that could potentially be leveraged for more sophisticated attacks.