CVE-2023-52838 in Linux
Summary
by MITRE • 05/21/2024
In the Linux kernel, the following vulnerability has been resolved:
fbdev: imsttfb: fix a resource leak in probe
I've re-written the error handling but the bug is that if init_imstt() fails we need to call iounmap(par->cmap_regs).
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Analysis
by VulDB Data Team • 12/04/2024
The vulnerability identified as CVE-2023-52838 represents a resource leak condition within the Linux kernel's framebuffer device driver specifically affecting the imsttfb driver. This flaw exists in the frame buffer subsystem where the kernel manages display hardware interfaces through device drivers. The imsttfb driver is responsible for handling certain display controllers that utilize the IMSTT framebuffer interface, which is typically found in embedded systems and specialized hardware configurations.
The technical root cause of this vulnerability stems from inadequate error handling within the driver's probe function. When the initialization function init_imstt() fails during driver setup, the system does not properly release previously allocated memory mappings. Specifically, the driver fails to invoke the iounmap() function on the par->cmap_regs memory region, which represents a crucial resource mapping for color palette registers. This oversight creates a memory leak where kernel virtual memory pages remain mapped and inaccessible even after the driver initialization process has failed, leading to gradual memory consumption over time.
The operational impact of this resource leak extends beyond simple memory waste, as it can potentially lead to system instability and performance degradation in embedded environments where memory resources are constrained. The vulnerability affects systems running Linux kernels that include the imsttfb driver, particularly those utilizing hardware configurations that require this specific framebuffer interface. Attackers could potentially exploit this condition to exhaust system memory resources through repeated driver initialization attempts, leading to denial of service conditions where legitimate system operations become impaired due to resource exhaustion.
This vulnerability aligns with CWE-404, which categorizes improper resource release or cleanup, and demonstrates characteristics consistent with the ATT&CK technique T1499.001 for resource exhaustion. The flaw represents a classic case of missing error path handling in kernel space code where proper cleanup routines are not executed following failure conditions. The fix implemented addresses this by ensuring that when init_imstt() returns an error status, the corresponding iounmap(par->cmap_regs) call is executed to properly release the memory mapping resources, thereby preventing the accumulation of leaked memory resources over time.
Mitigation strategies for this vulnerability primarily involve applying the kernel patch that corrects the error handling logic within the imsttfb driver's probe function. System administrators should prioritize updating their Linux kernel installations to versions containing the fix, particularly in embedded systems or environments where resource constraints make memory leaks more impactful. Additionally, monitoring systems for unusual memory consumption patterns could help detect potential exploitation of this vulnerability, though the primary defense remains the kernel update process that ensures proper resource management during driver initialization failures.