Overview
About vulnerability
In the Linux kernel, the following vulnerability has been resolved:
ntfs: sanitize MFT references returned from ntfs_lookup_inode_by_name()
ntfs_lookup_inode_by_name() returns MFT references read from directory index entries on disk. These values are untrusted, but the function can currently return an error-marked MFT reference to its callers without validating it.
Callers later decode lookup failures with MREF_ERR(). A crafted NTFS image can set the MREF error bit while leaving the low bits as an arbitrary value, causing callers to consume a bogus pseudo-errno instead of treating the lookup result as corrupted on-disk metadata.
Fix this at the source by normalizing every error-marked MFT reference returned from ntfs_lookup_inode_by_name() to ERR_MREF(-EIO). Apply this to all four directory lookup return paths so every caller gets a validated result without needing additional checks or an API change.
This keeps the sanitization in the common lookup helper, which is cleaner than duplicating validation in each caller.
Details
- Affected product:
- Debian 10 ELS
- Affected packages:
- linux @ 4.19.0