CVE-2005-0532 in Linux
Summary
by MITRE
The reiserfs_copy_from_user_to_file_region function in reiserfs/file.c for Linux kernel 2.6.10 and 2.6.11 before 2.6.11-rc4, when running on 64-bit architectures, may allow local users to trigger a buffer overflow as a result of casting discrepancies between size_t and int data types.
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Analysis
by VulDB Data Team • 07/01/2019
The vulnerability described in CVE-2005-0532 represents a critical buffer overflow condition within the Linux kernel's reiserfs file system implementation. This flaw specifically affects kernel versions 2.6.10 through 2.6.11-rc3 and manifests exclusively on 64-bit architectural platforms. The issue stems from a fundamental type casting discrepancy that occurs during the processing of user-space data transfers to file regions within the reiserfs file system. The affected function reiserfs_copy_from_user_to_file_region demonstrates a dangerous assumption about data type sizes that creates exploitable conditions for local privilege escalation.
The technical root cause of this vulnerability lies in the improper handling of data type conversions between size_t and int types within the kernel's memory management routines. When operating on 64-bit systems, the size_t data type can accommodate values up to 2^64-1, while int data types are typically limited to 32-bit signed integers with a maximum value of 2^31-1. This discrepancy becomes problematic when the kernel performs operations that assume the size_t value can be safely cast to int without overflow checking. The vulnerability occurs because the function fails to validate that the size parameter, which originates from user space and is of type size_t, can be properly represented as an int without truncation or overflow.
The operational impact of this vulnerability is significant for systems running affected kernel versions on 64-bit hardware. Local users with access to the system can exploit this buffer overflow condition to potentially execute arbitrary code with kernel-level privileges. The attack vector requires local system access but does not necessitate network connectivity or external exploitation mechanisms. The buffer overflow can lead to memory corruption that may allow privilege escalation, system crashes, or potentially remote code execution depending on the specific system configuration and memory layout. This vulnerability directly violates the principle of least privilege and undermines the kernel's memory safety mechanisms.
This vulnerability maps to CWE-121 in the Common Weakness Enumeration catalog, which covers stack-based buffer overflow conditions, and also relates to CWE-122 for heap-based buffer overflow scenarios. The attack pattern aligns with techniques described in the MITRE ATT&CK framework under the T1068 privilege escalation tactics, specifically targeting kernel vulnerabilities to gain elevated system privileges. The exploitation of this vulnerability requires understanding of kernel memory management, type casting behaviors, and the specific architecture-dependent characteristics of 64-bit systems. System administrators should implement immediate patching strategies for all affected kernel versions, as the vulnerability presents a clear path for local privilege escalation that could compromise entire system integrity. The fix involves proper validation of size parameter conversions and ensuring that user-provided size values are properly checked against int type limitations before casting operations occur.