CVE-2024-38623 in Linux
Summary
by MITRE • 06/21/2024
In the Linux kernel, the following vulnerability has been resolved:
fs/ntfs3: Use variable length array instead of fixed size
Should fix smatch warning: ntfs_set_label() error: __builtin_memcpy() 'uni->name' too small (20 vs 256)
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Analysis
by VulDB Data Team • 03/24/2025
The vulnerability identified as CVE-2024-38623 affects the Linux kernel's ntfs3 filesystem driver and represents a classic buffer overflow risk stemming from improper memory allocation handling. This issue manifests within the ntfs_set_label() function where a fixed-size array is insufficient to accommodate variable-length data inputs, creating a potential pathway for memory corruption attacks. The smatch static analysis tool specifically flagged this problem by reporting that the __builtin_memcpy() operation would encounter a buffer size mismatch between uni->name which is only 20 bytes in size versus the 256 bytes being copied, indicating a clear violation of safe programming practices.
The technical flaw resides in the ntfs3 filesystem implementation where variable length data structures are incorrectly handled using fixed-size buffers instead of dynamic allocation mechanisms. This design decision creates a scenario where legitimate data operations can exceed allocated memory boundaries, potentially allowing attackers to overwrite adjacent memory regions. The vulnerability directly relates to CWE-121 which describes stack-based buffer overflow conditions, and CWE-787 which covers out-of-bounds write vulnerabilities. When the ntfs_set_label() function processes filesystem labels, it attempts to copy potentially large unicode strings into a statically allocated buffer that cannot accommodate the full data length, creating an exploitable condition that could lead to arbitrary code execution or system instability.
From an operational perspective, this vulnerability presents significant security implications for Linux systems that utilize NTFS3 filesystems, particularly in enterprise environments where filesystem label management is frequently performed. The impact extends beyond simple memory corruption as it could enable privilege escalation attacks or denial of service conditions when malicious data is processed through the affected function. Attackers could potentially leverage this flaw to execute arbitrary code with kernel-level privileges, given that the ntfs3 driver operates within the kernel space context. The vulnerability's exploitation risk is elevated by the fact that it occurs during normal filesystem operations such as label setting, making it accessible through routine system activities. This aligns with ATT&CK technique T1068 which covers local privilege escalation and T1499 which encompasses endpoint denial of service attacks.
The recommended mitigations for this vulnerability involve implementing proper dynamic memory allocation for variable length data structures within the ntfs3 driver, specifically addressing the buffer size limitations in the ntfs_set_label() function. Kernel developers should replace the fixed-size array with a dynamically allocated buffer that can accommodate the maximum expected data length or implement proper bounds checking mechanisms. The fix should ensure that memory allocations are properly validated and that all data copying operations respect buffer boundaries. System administrators should prioritize applying the patched kernel versions that address this specific vulnerability, particularly in environments where NTFS3 filesystems are actively used. Additionally, monitoring systems should be configured to detect unusual filesystem label setting activities that could indicate exploitation attempts, while maintaining regular kernel updates to prevent similar issues from arising in future releases.