hesela.devfscrypt
fscrypt is Linux's filesystem-integrated encryption facility for file contents and names under directory-tree policies.
Linux v6.12 leaves sizes, timestamps, permissions, extended attributes and hole locations exposed. It does not guarantee protection against offline tampering. After unlocking, ordinary access controls still apply. [1]
This is the kernel facility, not the similarly named userspace tool. It differs from block-level dm-crypt and from fs-verity's integrity checks. [1] [2]
For v2 policies, removal first drops the caller's claim. ENOKEY can mean the caller has no claim while another user retains one. With OTHER_USERS set, a clear FILES_BUSY bit does not prove all files are closed. Key-status queries cover the filesystem keyring, not every key copy. [1]
Relations
- related
- Inline encryption, dm-crypt, fs-verity, Ext4 data journaling, Authenticated encryption, Cryptographic erase, fscrypt encryption policy, fscrypt v2 key identifier
Limitations
- Removing a master key does not necessarily remove in-use per-file keys or erase cached plaintext. [1]
Citations
- Linux v6.12: fscrypt, threat model, removing keys and getting key status
- Linux v6.12: fs-verity, integrity and authentication policy