There are two existing offline integrity models: file level integrity (linux-integrity subsystem EVM/IMA-appraisal) and block level integrity (dm-verity, dm-crypt). This patch provides a new block level method called device-mapper "integrity" target (dm-integrity), which provides transparent cryptographic integrity protection of the underlying read-write block device using hash-based message authentication codes (HMACs). The HMACs can be stored on the same or different block device. dm-integrity uses an encrypted key type, stored on the kernel keyring, to obtain a secret key for use in cryptographic operations. Encrypted keys are never exposed in plain text to user space. The encrypted keys are encrypted using master key, which can either be a user defined or trusted key type. The secret key, which is usually device specific, binds integrity data to the device. As a result data blocks and corresponding HMACs cannot simply be copied over from other file systems. EVM/IMA-appraisal provides file level integrity protection. The advantages are that it is policy based, file measurements are available for remote attestation, and files can be digitally signed to provide authenticity. Both dm-verity and dm-crypt provide block level integrity protection. dm-verity provides block level integrity protection for read-only file systems, while dm-crypt provides block level integrity protection, with minimum penalty, for filesystems requiring full disk encryption. dm-integrity provides a lighter weight read-write block level integrity protection for file systems not requiring full disk encryption, but which do require writability. - Dmitry Dmitry Kasatkin (1): dm-integrity: integrity protection device-mapper target Documentation/device-mapper/dm-integrity.txt | 125 ++++ drivers/md/Kconfig | 12 + drivers/md/Makefile | 1 + drivers/md/dm-integrity.c | 1019 ++++++++++++++++++++++++++ 4 files changed, 1157 insertions(+) create mode 100644 Documentation/device-mapper/dm-integrity.txt create mode 100644 drivers/md/dm-integrity.c -- 1.7.9.5 -- To unsubscribe from this list: send the line "unsubscribe linux-crypto" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
