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| author | Nathan Huckleberry <nhuck@google.com> | 2022-05-20 21:15:01 +0300 |
|---|---|---|
| committer | Herbert Xu <herbert@gondor.apana.org.au> | 2022-06-10 11:40:18 +0300 |
| commit | 6b2a51ff03bf0c54cbc699ee85a9a49eb203ebfc (patch) | |
| tree | 8110bcd6c9baaedb35a031ae2529b2e47fa74269 /fs/crypto/keysetup.c | |
| parent | 9d2c0b485c46c7c5f781067c60300def5d1365cb (diff) | |
| download | linux-6b2a51ff03bf0c54cbc699ee85a9a49eb203ebfc.tar.xz | |
fscrypt: Add HCTR2 support for filename encryption
HCTR2 is a tweakable, length-preserving encryption mode that is intended
for use on CPUs with dedicated crypto instructions. HCTR2 has the
property that a bitflip in the plaintext changes the entire ciphertext.
This property fixes a known weakness with filename encryption: when two
filenames in the same directory share a prefix of >= 16 bytes, with
AES-CTS-CBC their encrypted filenames share a common substring, leaking
information. HCTR2 does not have this problem.
More information on HCTR2 can be found here: "Length-preserving
encryption with HCTR2": https://eprint.iacr.org/2021/1441.pdf
Signed-off-by: Nathan Huckleberry <nhuck@google.com>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Acked-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Diffstat (limited to 'fs/crypto/keysetup.c')
| -rw-r--r-- | fs/crypto/keysetup.c | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/fs/crypto/keysetup.c b/fs/crypto/keysetup.c index c35711896bd4..fbc71abdabe3 100644 --- a/fs/crypto/keysetup.c +++ b/fs/crypto/keysetup.c @@ -53,6 +53,13 @@ struct fscrypt_mode fscrypt_modes[] = { .ivsize = 32, .blk_crypto_mode = BLK_ENCRYPTION_MODE_ADIANTUM, }, + [FSCRYPT_MODE_AES_256_HCTR2] = { + .friendly_name = "AES-256-HCTR2", + .cipher_str = "hctr2(aes)", + .keysize = 32, + .security_strength = 32, + .ivsize = 32, + }, }; static DEFINE_MUTEX(fscrypt_mode_key_setup_mutex); |