Re: [PATCH v4 2/4] fscrypt: add inline encryption support

[tytso@mit.edu]

On Thu, Jul 02, 2020 at 01:56:05AM +0000, Satya Tangirala wrote:
> Add support for inline encryption to fs/crypto/.  With "inline
> encryption", the block layer handles the decryption/encryption as part
> of the bio, instead of the filesystem doing the crypto itself via
> Linux's crypto API. This model is needed in order to take advantage of
> the inline encryption hardware present on most modern mobile SoCs.
> 
> To use inline encryption, the filesystem needs to be mounted with
> '-o inlinecrypt'. Blk-crypto will then be used instead of the traditional
> filesystem-layer crypto whenever possible to encrypt the contents
> of any encrypted files in that filesystem. Fscrypt still provides the key
> and IV to use, and the actual ciphertext on-disk is still the same;
> therefore it's testable using the existing fscrypt ciphertext verification
> tests.
> 
> Note that since blk-crypto has a fallback to Linux's crypto API, and
> also supports all the encryption modes currently supported by fscrypt,
> this feature is usable and testable even without actual inline
> encryption hardware.
> 
> Per-filesystem changes will be needed to set encryption contexts when
> submitting bios and to implement the 'inlinecrypt' mount option.  This
> patch just adds the common code.
> 
> Co-developed-by: Eric Biggers <ebiggers@google.com>
> Signed-off-by: Eric Biggers <ebiggers@google.com>
> Signed-off-by: Satya Tangirala <satyat@google.com>
> Reviewed-by: Jaegeuk Kim <jaegeuk@kernel.org>
> Reviewed-by: Eric Biggers <ebiggers@google.com>

Reviewed-by: Theodore Ts'o <tytso@mit.edu>