CVE-2023-52785 in Linux
Summary
by MITRE • 05/21/2024
In the Linux kernel, the following vulnerability has been resolved:
scsi: ufs: core: Fix racing issue between ufshcd_mcq_abort() and ISR
If command timeout happens and cq complete IRQ is raised at the same time, ufshcd_mcq_abort clears lprb->cmd and a NULL pointer deref happens in the ISR. Error log:
ufshcd_abort: Device abort task at tag 18 Unable to handle kernel NULL pointer dereference at virtual address 0000000000000108 pc : [0xffffffe27ef867ac] scsi_dma_unmap+0xc/0x44
lr : [0xffffffe27f1b898c] ufshcd_release_scsi_cmd+0x24/0x114
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Analysis
by VulDB Data Team • 05/21/2024
The vulnerability CVE-2023-52785 represents a critical race condition within the Linux kernel's Universal Flash Storage subsystem, specifically affecting the UFS core driver implementation. This flaw manifests in the interaction between the command queue abort mechanism and the interrupt service routine, creating a scenario where concurrent execution paths can lead to system instability and potential kernel panics. The issue occurs when command timeouts are processed simultaneously with completion queue interrupt notifications, exposing a fundamental synchronization problem in the device management layer that governs how asynchronous operations are handled.
The technical root cause of this vulnerability stems from inadequate synchronization between the ufshcd_mcq_abort() function and the interrupt service routine that processes command completion events. When a command timeout occurs while the completion queue interrupt is simultaneously being processed, the abort function clears the command structure reference (lprb->cmd) before the interrupt handler has completed its execution. This creates a classic race condition where the interrupt handler attempts to access a null pointer at virtual address 0x0000000000000108, resulting in a kernel NULL pointer dereference that terminates system operation. The error trace indicates that the scsi_dma_unmap function attempts to process a null pointer, while the ufshcd_release_scsi_cmd function serves as the point of origin for the invalid memory access, demonstrating how the race condition propagates through the kernel's storage subsystem.
The operational impact of CVE-2023-52785 extends beyond simple system crashes, potentially affecting data integrity and system availability in production environments that rely on UFS storage devices. Systems utilizing UFS controllers in high-throughput scenarios or those experiencing network latency variations that cause command timeouts are particularly vulnerable to this race condition. The vulnerability affects the broader UFS storage ecosystem and can compromise the stability of servers, embedded systems, and mobile devices that depend on reliable storage operations. When triggered, this flaw can cause complete system hangs, requiring manual intervention or reboot to restore normal operation, thereby introducing unacceptable downtime in mission-critical applications.
Mitigation strategies for CVE-2023-52785 require immediate kernel updates to address the synchronization issue through proper locking mechanisms or atomic operations between the command abort and interrupt processing paths. System administrators should prioritize patching affected kernels, particularly those running versions containing the vulnerable UFS core driver implementation. Additional defensive measures include monitoring for command timeout patterns that might indicate race condition triggering, implementing proper kernel debugging configurations to detect similar race conditions, and maintaining system logs to identify potential exploitation attempts. Organizations should also consider implementing redundant storage solutions or fallback mechanisms to maintain system availability during patch deployment windows. The fix typically involves introducing appropriate mutex or spinlock mechanisms to ensure exclusive access to command structures during abort operations, preventing the interrupt handler from accessing freed memory references. This vulnerability aligns with CWE-362, which describes race conditions in concurrent programming, and represents a classic example of improper synchronization that can be addressed through proper kernel-level concurrency controls as recommended in industry security best practices.