[This patchset is based on the master branch of https://git.kernel.org/pub/scm/fs/fscrypt/fscrypt.git. It can also be retrieved from the tag "wrapped-keys-v6" of the same repo.] This patchset adds the block and fscrypt support for hardware-wrapped inline encryption keys, a security feature supported by recent Qualcomm and Google SoCs. Unfortunately, although this feature has already been working in Android for several years (with some slight differences in the software design), the SoC-specific software support needed to actually test and use this feature end-to-end with the upstream kernel continues to not be ready, mostly for reasons outside my control. Therefore, I've downgraded this patchset back to a RFC. Nevertheless, I'd greatly appreciate feedback on it. This feature is described in full detail in the included Documentation changes. But to summarize, hardware-wrapped keys are inline encryption keys that are wrapped (encrypted) by a key internal to the hardware so that they can only be unwrapped (decrypted) by the hardware. Initially keys are wrapped with a permanent hardware key, but during actual use they are re-wrapped with a per-boot ephemeral key for improved security. The hardware supports importing keys as well as generating keys itself. This feature protects encryption keys from read-only compromises of kernel memory, such as that which can occur during a cold boot attack. It does this without limiting the number of keys that can be used, as would be the case with solutions that didn't use key wrapping. This differs from the existing support for hardware-wrapped keys in the kernel crypto API (which also goes by names such as "hardware-bound keys", depending on the driver) in the same way that the crypto API differs from blk-crypto: the crypto API is for general crypto operations, whereas blk-crypto is for inline storage encryption. I've written xfstests which test that this feature encrypts files correctly. I've sent these separately, and the latest version is at https://git.kernel.org/pub/scm/linux/kernel/git/ebiggers/xfstests-dev.git/log/?h=wip-wrapped-keys. Changed v5 => v6: - Downgraded the patchset back to RFC status. - Exposed the supported key types in sysfs. - Shortened some field names, e.g. longterm_wrapped_key => lt_key. - Avoided adding a new use of struct request_queue by fs/crypto/. - Moved the blk-crypto ioctls to a new blk-crypto UAPI header file and fixed their numbering. - Other cleanups. Changed v4 => v5: - Dropped the RFC tag, now that these patches are actually testable. - Split the BLKCRYPTOCREATEKEY ioctl into BLKCRYPTOIMPORTKEY and BLKCRYPTOGENERATEKEY. (I'm thinking that these operations are distinct enough that two separate ioctls would be best.) - Added some warning messages in fscrypt_derive_sw_secret(). - Rebased onto v5.17-rc6. Changed v3 => v4: - Rebased onto v5.16-rc1 and dropped a few bits that were upstreamed. - Updated cover letter to link to Gaurav's UFS driver patchset. Changed v2 => v3: - Dropped some fscrypt cleanups that were applied. - Rebased on top of the latest linux-block and fscrypt branches. - Minor cleanups. Changed v1 => v2: - Added new ioctls for creating and preparing hardware-wrapped keys. - Rebased onto my patchset which renames blk_keyslot_manager to blk_crypto_profile. Eric Biggers (4): blk-crypto: add basic hardware-wrapped key support blk-crypto: show supported key types in sysfs blk-crypto: add ioctls to create and prepare hardware-wrapped keys fscrypt: add support for hardware-wrapped keys Documentation/ABI/stable/sysfs-block | 18 ++ Documentation/block/inline-encryption.rst | 245 +++++++++++++++++- Documentation/filesystems/fscrypt.rst | 154 +++++++++-- .../userspace-api/ioctl/ioctl-number.rst | 4 +- block/blk-crypto-fallback.c | 5 +- block/blk-crypto-internal.h | 10 + block/blk-crypto-profile.c | 119 +++++++++ block/blk-crypto-sysfs.c | 35 +++ block/blk-crypto.c | 193 +++++++++++++- block/ioctl.c | 5 + drivers/md/dm-table.c | 1 + drivers/mmc/host/cqhci-crypto.c | 2 + drivers/ufs/core/ufshcd-crypto.c | 1 + fs/crypto/fscrypt_private.h | 70 ++++- fs/crypto/hkdf.c | 4 +- fs/crypto/inline_crypt.c | 64 ++++- fs/crypto/keyring.c | 122 ++++++--- fs/crypto/keysetup.c | 54 +++- fs/crypto/keysetup_v1.c | 5 +- fs/crypto/policy.c | 11 +- include/linux/blk-crypto-profile.h | 73 ++++++ include/linux/blk-crypto.h | 78 +++++- include/uapi/linux/blk-crypto.h | 44 ++++ include/uapi/linux/fs.h | 6 +- include/uapi/linux/fscrypt.h | 7 +- 25 files changed, 1233 insertions(+), 97 deletions(-) create mode 100644 include/uapi/linux/blk-crypto.h base-commit: 0e91fc1e0f5c70ce575451103ec66c2ec21f1a6e -- 2.37.3
