CVE-2024-50211 in Linux
Summary
by MITRE • 11/08/2024
In the Linux kernel, the following vulnerability has been resolved:
udf: refactor inode_bmap() to handle error
Refactor inode_bmap() to handle error since udf_next_aext() can return error now. On situations like ftruncate, udf_extend_file() can now detect errors and bail out early without resorting to checking for particular offsets and assuming internal behavior of these functions.
Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.
Analysis
by VulDB Data Team • 01/22/2025
The vulnerability identified as CVE-2024-50211 represents a critical improvement in the Linux kernel's Universal Disk Format UDF filesystem implementation that addresses potential error handling deficiencies in the inode_bmap() function. This issue specifically targets the file system's ability to properly manage and respond to error conditions during file operations, particularly those involving file truncation and extension processes. The vulnerability stems from the fact that udf_next_aext() function can now return error codes, which previously were not properly accounted for in the inode_bmap() implementation. This refactoring addresses a fundamental flaw in the filesystem's error propagation mechanism that could lead to inconsistent file system states and potential data corruption scenarios.
The technical flaw manifests in how the UDF filesystem handles error conditions during file extension operations, particularly when processing ftruncate system calls. Prior to this fix, the inode_bmap() function relied on implicit error checking mechanisms that assumed specific internal behaviors of underlying functions like udf_extend_file(). This approach was inherently fragile and could lead to situations where errors were silently ignored or improperly handled, potentially causing the filesystem to enter inconsistent states. The refactoring addresses this by explicitly checking for error returns from udf_next_aext() and allowing udf_extend_file() to detect and respond to these errors appropriately, thereby enabling early termination of problematic operations before they could cause further system instability.
The operational impact of this vulnerability extends beyond simple error handling to encompass broader filesystem reliability and data integrity concerns. When file truncation operations fail to properly detect and respond to errors, the filesystem may continue processing with corrupted or inconsistent metadata, potentially leading to data loss or filesystem corruption. This type of vulnerability is particularly concerning in enterprise environments where UDF filesystems are commonly used for optical media storage, backup operations, and cross-platform compatibility scenarios. The vulnerability affects systems running Linux kernels that implement UDF filesystem support, particularly those handling frequent file extension or truncation operations, with potential implications for storage subsystem stability and overall system reliability.
This vulnerability aligns with CWE-755 weakness classification, which specifically addresses improper handling of exceptional conditions in software implementations. The fix represents a significant improvement in adherence to secure coding practices by explicitly handling error return codes rather than relying on implicit error detection mechanisms. From an ATT&CK framework perspective, this vulnerability could be leveraged in persistence or privilege escalation scenarios if exploited in conjunction with other filesystem vulnerabilities, though its primary impact is focused on system stability and data integrity. The mitigation strategy involves updating to kernel versions that include this refactored implementation, which provides explicit error handling for the udf_next_aext() function return values. System administrators should prioritize this update, particularly in environments where UDF filesystems are heavily utilized for critical data storage operations, as the vulnerability represents a foundational issue in filesystem error management that could compound other security concerns.