On Mon, Oct 05, 2020 at 07:36:03AM +0000, Satya Tangirala wrote: > This patch series adds support for metadata encryption to F2FS using > blk-crypto. > > Patch 1 replaces fscrypt_get_devices (which took an array of request_queues > and filled it up) with fscrypt_get_device, which takes a index of the > desired device and returns the device at that index (so the index passed > to fscrypt_get_device must be between 0 and (fscrypt_get_num_devices() - 1) > inclusive). This allows callers to avoid having to allocate an array to > pass to fscrypt_get_devices() when they only need to iterate through > each element in the array (and have no use for the array itself). > > Patch 2 introduces some functions to fscrypt that help filesystems perform > metadata encryption. Any filesystem that wants to use metadata encryption > can call fscrypt_setup_metadata_encryption() with the super_block of the > filesystem, the encryption algorithm and the descriptor of the encryption > key. The descriptor is looked up in the logon keyring of the current > session with "fscrypt:" as the prefix of the descriptor. > > The patch also introduces fscrypt_metadata_crypt_bio() which an FS should > call on a bio that the FS wants metadata crypted. The function will add > an encryption context with the metadata encryption key set up by the call > to the above mentioned fscrypt_setup_metadata_encryption(). > > The patch also introduces fscrypt_metadata_crypt_prepare_all_devices(). > Filesystems that use multiple devices should call this function once all > the underlying devices have been determined. An FS might only be able to > determine all the underlying devices after some initial processing that > might already require metadata en/decryption, which is why this function > is separate from fscrypt_setup_metadata_encryption(). > > Patch 3 wires up F2FS with the functions introduced in Patch 2. F2FS > will encrypt every block (that's not being encrypted by some other > encryption key, e.g. a per-file key) with the metadata encryption key > except the superblock (and the redundant copy of the superblock). The DUN > of a block is the offset of the block from the start of the F2FS > filesystem. > > Please refer to the commit message for why the superblock was excluded from > en/decryption, and other limitations. The superblock and its copy are > stored in plaintext on disk. The encryption algorithm used for metadata > encryption is stored within the superblock itself. Changes to the userspace > tools (that are required to test out metadata encryption with F2FS) are > also being sent out - I'll post a link as a reply to this mail once it's > out. The userspace patches are at https://lore.kernel.org/linux-fscrypt/20201005074133.1958633-2-satyat@xxxxxxxxxx/ > > Satya Tangirala (3): > fscrypt, f2fs: replace fscrypt_get_devices with fscrypt_get_device > fscrypt: Add metadata encryption support > f2fs: Add metadata encryption support > > Documentation/filesystems/f2fs.rst | 12 ++ > fs/crypto/Kconfig | 6 + > fs/crypto/Makefile | 1 + > fs/crypto/fscrypt_private.h | 19 +++ > fs/crypto/inline_crypt.c | 37 +---- > fs/crypto/metadata_crypt.c | 220 +++++++++++++++++++++++++++++ > fs/f2fs/data.c | 24 ++-- > fs/f2fs/f2fs.h | 2 + > fs/f2fs/super.c | 83 +++++++++-- > include/linux/f2fs_fs.h | 3 +- > include/linux/fs.h | 3 + > include/linux/fscrypt.h | 51 ++++++- > 12 files changed, 410 insertions(+), 51 deletions(-) > create mode 100644 fs/crypto/metadata_crypt.c > > -- > 2.28.0.806.g8561365e88-goog >
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