CVE-2004-2302 in Linux
Summary
by MITRE
Race condition in the sysfs_read_file and sysfs_write_file functions in Linux kernel before 2.6.10 allows local users to read kernel memory and cause a denial of service (crash) via large offsets in sysfs files.
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Analysis
by VulDB Data Team • 07/15/2019
The vulnerability described in CVE-2004-2302 represents a critical race condition within the Linux kernel's sysfs filesystem implementation that affects versions prior to 2.6.10. This flaw exists in the sysfs_read_file and sysfs_write_file functions, which are responsible for managing file operations within the sysfs virtual filesystem. The sysfs filesystem provides an interface for exposing kernel data structures and device information to user space, making it a critical component for system monitoring and device management. The race condition occurs when concurrent access to sysfs files is attempted with large offset values, creating a scenario where the kernel's memory management and file handling mechanisms fail to properly synchronize access to shared resources.
The technical exploitation of this vulnerability stems from improper handling of file offsets during read and write operations in the sysfs subsystem. When local users submit large offset values to sysfs files, the kernel's internal buffer management and memory access routines do not adequately protect against concurrent access patterns that can lead to memory corruption. This race condition allows attackers to potentially access kernel memory locations that should remain protected, as the synchronization mechanisms fail to prevent simultaneous read and write operations from interfering with each other. The flaw manifests as a direct consequence of insufficient locking mechanisms and improper bounds checking within the sysfs file handling functions, particularly when dealing with large data structures and offset values that exceed normal operational parameters.
The operational impact of this vulnerability extends beyond simple denial of service to include potential information disclosure and system instability. Local users can leverage this race condition to read kernel memory contents, which may contain sensitive information such as cryptographic keys, passwords, or other confidential system data. The vulnerability can also cause system crashes and denial of service conditions when the race condition results in memory corruption or invalid memory access patterns. This makes the vulnerability particularly dangerous in multi-user environments where local users might attempt to exploit it to gain unauthorized access to kernel memory or disrupt system operations. The potential for information disclosure combined with the denial of service capabilities creates a significant security risk that affects the overall integrity and availability of affected systems.
Mitigation strategies for this vulnerability require immediate kernel updates to versions 2.6.10 or later where the race condition has been addressed through proper synchronization mechanisms and enhanced bounds checking. System administrators should prioritize applying the relevant security patches and updates to eliminate the risk of exploitation. Additional defensive measures include implementing proper access controls and monitoring for unusual sysfs file access patterns, as well as conducting regular security audits to identify potential exploitation attempts. The vulnerability aligns with CWE-362, which describes race conditions in software systems, and represents a classic example of insufficient synchronization in kernel-level code. From an ATT&CK perspective, this vulnerability maps to techniques involving privilege escalation and information gathering through kernel-level access, making it a significant concern for organizations that rely on Linux systems for critical operations. The fix implemented in kernel versions 2.6.10 and later demonstrates the importance of proper locking mechanisms and memory management in preventing race conditions that can lead to security breaches and system instability.