EXT4 With Linux 5.13 Looks Like It Will Support Casefolding With Encryption Enabled

Written by Michael Larabel in Linux Storage on 11 April 2021 at 05:48 AM EDT. 5 Comments
While EXT4 supports both case-folding for optional case insensitive filenames and does support file-system encryption, at the moment those features are mutually exclusive. But it looks like the upcoming Linux 5.13 kernel will allow casefolding and encryption to be active at the same time.

Queued this week into the EXT4 file-system's "dev" tree was ext4: handle casefolding with encryption.

That work allows for encryption to happen with casefolding. Google's Daniel Rosenberg who worked on the change explained, "Since the name on disk is case preserving, and also encrypted, we can no longer just recompute the hash on the fly. Additionally, to avoid leaking extra information from the hash of the unencrypted name, we use siphash via an fscrypt v2 policy. The hash is stored at the end of the directory entry for all entries inside of an encrypted and casefolded directory apart from those that deal with '.' and '..'. This way, the change is backwards compatible with existing ext4 filesystems."

Earlier this year the FSCRYPT file-system encryption framework was working on casefolding integration. The F2FS file-system has supported case-folding and encryption together since Linux 5.11. EXT4's turn looks to be with Linux 5.13.
Related News
About The Author
Michael Larabel

Michael Larabel is the principal author of Phoronix.com and founded the site in 2004 with a focus on enriching the Linux hardware experience. Michael has written more than 20,000 articles covering the state of Linux hardware support, Linux performance, graphics drivers, and other topics. Michael is also the lead developer of the Phoronix Test Suite, Phoromatic, and OpenBenchmarking.org automated benchmarking software. He can be followed via Twitter, LinkedIn, or contacted via MichaelLarabel.com.

Popular News This Week