CVE-2024-57262 in Barebox
Summary
by MITRE • 02/19/2025
In barebox before 2025.01.0, ext4fs_read_symlink has an integer overflow for zalloc (adding one to an le32 variable) via a crafted ext4 filesystem with an inode size of 0xffffffff, resulting in a malloc of zero and resultant memory overwrite, a related issue to CVE-2024-57256.
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Analysis
by VulDB Data Team • 06/01/2025
The vulnerability identified as CVE-2024-57262 affects the barebox bootloader software version prior to 2025.01.0 and specifically targets the ext4fs_read_symlink function within the ext4 filesystem implementation. This integer overflow condition arises from improper handling of filesystem metadata structures, particularly when processing symbolic links within ext4 filesystems. The flaw manifests when the system encounters a crafted ext4 filesystem containing an inode with a size value of 0xffffffff, which represents the maximum value for a 32-bit little-endian unsigned integer. The vulnerability stems from the zalloc function being called with an argument that results from adding one to a le32 variable, creating an arithmetic overflow condition that ultimately leads to memory allocation failure.
The technical implementation of this vulnerability involves a classic integer overflow scenario where the le32 variable representing inode size is incremented without proper bounds checking. When the inode size reaches the maximum 32-bit value of 0xffffffff and one is added to it, the result wraps around to zero due to unsigned integer overflow behavior. This zero value is then passed to the malloc function, which allocates zero bytes of memory, creating a memory overwrite condition. The underlying issue is particularly dangerous because it allows an attacker to craft a malicious ext4 filesystem that can cause the bootloader to allocate insufficient memory, leading to memory corruption that can be exploited for arbitrary code execution or system instability. This vulnerability is categorized under CWE-190 as an Integer Overflow or Wraparound, and specifically relates to CWE-704 as an Incorrect Type Conversion or Cast.
The operational impact of CVE-2024-57262 is severe for systems relying on barebox as their primary bootloader, particularly in embedded environments where bootloader security is paramount. Attackers who can influence the filesystem that barebox reads during boot can potentially execute code by crafting malicious ext4 filesystems with specially crafted inodes. The memory overwrite condition can lead to privilege escalation, system crashes, or more sophisticated exploitation techniques that leverage the corrupted memory state. This vulnerability particularly affects devices using barebox as a bootloader in IoT appliances, network equipment, and embedded systems where attackers might have the ability to modify storage media or influence the boot process through physical access or network-based attacks. The related vulnerability CVE-2024-57256 indicates a pattern of similar integer overflow issues within the same codebase, suggesting a systemic weakness in the handling of filesystem metadata structures.
Mitigation strategies for CVE-2024-57262 require immediate software updates to version 2025.01.0 or later, which contains the necessary patches to address the integer overflow condition in ext4fs_read_symlink. Organizations should also implement robust filesystem validation mechanisms to prevent loading of untrusted or malformed ext4 filesystems, particularly in environments where the bootloader might encounter user-supplied storage media. The fix should include proper bounds checking for le32 variables before arithmetic operations and validation of inode sizes to ensure they do not exceed reasonable limits. Security teams should also consider implementing runtime protections such as stack canaries, address space layout randomization, and memory integrity checks to detect and prevent exploitation attempts. Additionally, system administrators should review and restrict filesystem access permissions for bootloader components, ensuring that only trusted storage media can be used during the boot process. The vulnerability highlights the importance of proper integer handling in low-level system software and aligns with ATT&CK technique T1059.001 for Command and Scripting Interpreter, as exploitation could enable attackers to execute malicious code within the bootloader environment, potentially leading to complete system compromise.