CVE-2021-47638

Name of the Vulnerable Software and Affected Versions Linux kernel (affected versions not specified)

Description A double-free issue has been identified in the Linux kernel, specifically in the ubifs module. The problem occurs when the rename whiteout operation fails due to a space budget issue, causing the whiteout ui->data to be freed twice. This is confirmed by KASAN reports, which indicate a double-free or invalid-free error in ubifs free inode. The issue arises from the rename whiteout process, where whiteout ui->data is allocated and then freed, but also freed again in ubifs free inode. The estimated number of potentially affected devices is not provided.

Recommendations To resolve the issue, let ubifs free inode() free whiteout ui->data. Additionally, remove the unused assignment whiteout ui->data len = 0, as it is not needed in the ubifs evict inode() process.