[PATCH v4 4/4] fscrypt: Add LEA-256-XTS, LEA-256-CTS support

Dongsoo Lee
2023-06-30T05:04:02Z

It uses LEA-256-XTS for file encryption and LEA-256-CTS-CBC for
filename encryption. Includes constant changes as the number of
supported ciphers increases.

Signed-off-by: Dongsoo Lee <letrhee@nsr.re.kr>
---
fs/crypto/fscrypt_private.h | 2 +-
fs/crypto/keysetup.c | 15 +++++++++++++++
fs/crypto/policy.c | 4 ++++
include/uapi/linux/fscrypt.h | 4 +++-
tools/include/uapi/linux/fscrypt.h | 4 +++-
5 files changed, 26 insertions(+), 3 deletions(-)

diff --git a/fs/crypto/fscrypt_private.h b/fs/crypto/fscrypt_private.h
index 2d63da48635a..df8075478f11 100644
--- a/fs/crypto/fscrypt_private.h
+++ b/fs/crypto/fscrypt_private.h
@@ -31,7 +31,7 @@
#define FSCRYPT_CONTEXT_V2 2

/* Keep this in sync with include/uapi/linux/fscrypt.h */
-#define FSCRYPT_MODE_MAX FSCRYPT_MODE_AES_256_HCTR2
+#define FSCRYPT_MODE_MAX FSCRYPT_MODE_LEA_256_CTS

struct fscrypt_context_v1 {
u8 version; /* FSCRYPT_CONTEXT_V1 */
diff --git a/fs/crypto/keysetup.c b/fs/crypto/keysetup.c
index 361f41ef46c7..fa82579e56eb 100644
--- a/fs/crypto/keysetup.c
+++ b/fs/crypto/keysetup.c
@@ -74,6 +74,21 @@ struct fscrypt_mode fscrypt_modes[] = {
.security_strength = 32,
.ivsize = 32,
},
+ [FSCRYPT_MODE_LEA_256_XTS] = {
+ .friendly_name = "LEA-256-XTS",
+ .cipher_str = "xts(lea)",
+ .keysize = 64,
+ .security_strength = 32,
+ .ivsize = 16,
+ .blk_crypto_mode = BLK_ENCRYPTION_MODE_LEA_256_XTS,
+ },
+ [FSCRYPT_MODE_LEA_256_CTS] = {
+ .friendly_name = "LEA-256-CTS-CBC",
+ .cipher_str = "cts(cbc(lea))",
+ .keysize = 32,
+ .security_strength = 32,
+ .ivsize = 16,
+ },
};

static DEFINE_MUTEX(fscrypt_mode_key_setup_mutex);
diff --git a/fs/crypto/policy.c b/fs/crypto/policy.c
index f4456ecb3f87..9d1e80c43c6d 100644
--- a/fs/crypto/policy.c
+++ b/fs/crypto/policy.c
@@ -94,6 +94,10 @@ static bool fscrypt_valid_enc_modes_v2(u32 contents_mode, u32 filenames_mode)
filenames_mode == FSCRYPT_MODE_SM4_CTS)
return true;

+ if (contents_mode == FSCRYPT_MODE_LEA_256_XTS &&
+ filenames_mode == FSCRYPT_MODE_LEA_256_CTS)
+ return true;
+
return fscrypt_valid_enc_modes_v1(contents_mode, filenames_mode);
}

diff --git a/include/uapi/linux/fscrypt.h b/include/uapi/linux/fscrypt.h
index fd1fb0d5389d..df3c8af98210 100644
--- a/include/uapi/linux/fscrypt.h
+++ b/include/uapi/linux/fscrypt.h
@@ -30,7 +30,9 @@
#define FSCRYPT_MODE_SM4_CTS 8
#define FSCRYPT_MODE_ADIANTUM 9
#define FSCRYPT_MODE_AES_256_HCTR2 10
-/* If adding a mode number > 10, update FSCRYPT_MODE_MAX in fscrypt_private.h */
+#define FSCRYPT_MODE_LEA_256_XTS 11
+#define FSCRYPT_MODE_LEA_256_CTS 12
+/* If adding a mode number > 12, update FSCRYPT_MODE_MAX in fscrypt_private.h */

/*
* Legacy policy version; ad-hoc KDF and no key verification.
diff --git a/tools/include/uapi/linux/fscrypt.h b/tools/include/uapi/linux/fscrypt.h
index fd1fb0d5389d..df3c8af98210 100644
--- a/tools/include/uapi/linux/fscrypt.h
+++ b/tools/include/uapi/linux/fscrypt.h
@@ -30,7 +30,9 @@
#define FSCRYPT_MODE_SM4_CTS 8
#define FSCRYPT_MODE_ADIANTUM 9
#define FSCRYPT_MODE_AES_256_HCTR2 10
-/* If adding a mode number > 10, update FSCRYPT_MODE_MAX in fscrypt_private.h */
+#define FSCRYPT_MODE_LEA_256_XTS 11
+#define FSCRYPT_MODE_LEA_256_CTS 12
+/* If adding a mode number > 12, update FSCRYPT_MODE_MAX in fscrypt_private.h */

/*
* Legacy policy version; ad-hoc KDF and no key verification.
--
2.34.1