SM4 is widely used in China's data encryption software and hardware.
This serial of patches enables the SM4-XTS algorithm in blk-crypto and
enables the SM4-XTS/CTS algorithm in fscrypt to encrypt file content
and filename.
v2 change:
- As Eric said, the new FSCRYPT_MODE is defined for the unused numbers 7 and 8
Tianjia Zhang (2):
blk-crypto: Add support for SM4-XTS blk crypto mode
fscrypt: Add SM4 XTS/CTS symmetric algorithm support
Documentation/filesystems/fscrypt.rst | 1 +
block/blk-crypto.c | 6 ++++++
fs/crypto/keysetup.c | 15 +++++++++++++++
fs/crypto/policy.c | 4 ++++
include/linux/blk-crypto.h | 1 +
include/uapi/linux/fscrypt.h | 2 ++
6 files changed, 29 insertions(+)
--
2.24.3 (Apple Git-128)
SM4 is a symmetric algorithm widely used in China, and SM4-XTS is also
used to encrypt length-preserving data, this patch enables the use of
SM4-XTS algorithm in block inline encryption, and provides support for
fscrypt.
Signed-off-by: Tianjia Zhang <[email protected]>
---
block/blk-crypto.c | 6 ++++++
include/linux/blk-crypto.h | 1 +
2 files changed, 7 insertions(+)
diff --git a/block/blk-crypto.c b/block/blk-crypto.c
index a496aaef85ba..e44709fc6a08 100644
--- a/block/blk-crypto.c
+++ b/block/blk-crypto.c
@@ -36,6 +36,12 @@ const struct blk_crypto_mode blk_crypto_modes[] = {
.keysize = 32,
.ivsize = 32,
},
+ [BLK_ENCRYPTION_MODE_SM4_XTS] = {
+ .name = "SM4-XTS",
+ .cipher_str = "xts(sm4)",
+ .keysize = 32,
+ .ivsize = 16,
+ },
};
/*
diff --git a/include/linux/blk-crypto.h b/include/linux/blk-crypto.h
index 69b24fe92cbf..26b1b71c3091 100644
--- a/include/linux/blk-crypto.h
+++ b/include/linux/blk-crypto.h
@@ -13,6 +13,7 @@ enum blk_crypto_mode_num {
BLK_ENCRYPTION_MODE_AES_256_XTS,
BLK_ENCRYPTION_MODE_AES_128_CBC_ESSIV,
BLK_ENCRYPTION_MODE_ADIANTUM,
+ BLK_ENCRYPTION_MODE_SM4_XTS,
BLK_ENCRYPTION_MODE_MAX,
};
--
2.24.3 (Apple Git-128)
SM4 is a symmetric algorithm widely used in China, this patch enables
to use SM4-XTS mode to encrypt file content, and use SM4-CBC-CTS to
encrypt filename.
Signed-off-by: Tianjia Zhang <[email protected]>
---
Documentation/filesystems/fscrypt.rst | 1 +
fs/crypto/keysetup.c | 15 +++++++++++++++
fs/crypto/policy.c | 4 ++++
include/uapi/linux/fscrypt.h | 2 ++
4 files changed, 22 insertions(+)
diff --git a/Documentation/filesystems/fscrypt.rst b/Documentation/filesystems/fscrypt.rst
index 5ba5817c17c2..af27e7b2c74f 100644
--- a/Documentation/filesystems/fscrypt.rst
+++ b/Documentation/filesystems/fscrypt.rst
@@ -336,6 +336,7 @@ Currently, the following pairs of encryption modes are supported:
- AES-256-XTS for contents and AES-256-CTS-CBC for filenames
- AES-128-CBC for contents and AES-128-CTS-CBC for filenames
+- SM4-XTS for contents and SM4-CTS-CBC for filenames
- Adiantum for both contents and filenames
- AES-256-XTS for contents and AES-256-HCTR2 for filenames (v2 policies only)
diff --git a/fs/crypto/keysetup.c b/fs/crypto/keysetup.c
index f7407071a952..24e55c95abc3 100644
--- a/fs/crypto/keysetup.c
+++ b/fs/crypto/keysetup.c
@@ -44,6 +44,21 @@ struct fscrypt_mode fscrypt_modes[] = {
.security_strength = 16,
.ivsize = 16,
},
+ [FSCRYPT_MODE_SM4_XTS] = {
+ .friendly_name = "SM4-XTS",
+ .cipher_str = "xts(sm4)",
+ .keysize = 32,
+ .security_strength = 16,
+ .ivsize = 16,
+ .blk_crypto_mode = BLK_ENCRYPTION_MODE_SM4_XTS,
+ },
+ [FSCRYPT_MODE_SM4_CTS] = {
+ .friendly_name = "SM4-CTS",
+ .cipher_str = "cts(cbc(sm4))",
+ .keysize = 16,
+ .security_strength = 16,
+ .ivsize = 16,
+ },
[FSCRYPT_MODE_ADIANTUM] = {
.friendly_name = "Adiantum",
.cipher_str = "adiantum(xchacha12,aes)",
diff --git a/fs/crypto/policy.c b/fs/crypto/policy.c
index 46757c3052ef..8e69bc0c35cd 100644
--- a/fs/crypto/policy.c
+++ b/fs/crypto/policy.c
@@ -71,6 +71,10 @@ static bool fscrypt_valid_enc_modes_v1(u32 contents_mode, u32 filenames_mode)
filenames_mode == FSCRYPT_MODE_AES_128_CTS)
return true;
+ if (contents_mode == FSCRYPT_MODE_SM4_XTS &&
+ filenames_mode == FSCRYPT_MODE_SM4_CTS)
+ return true;
+
if (contents_mode == FSCRYPT_MODE_ADIANTUM &&
filenames_mode == FSCRYPT_MODE_ADIANTUM)
return true;
diff --git a/include/uapi/linux/fscrypt.h b/include/uapi/linux/fscrypt.h
index a756b29afcc2..47dbd1994bfe 100644
--- a/include/uapi/linux/fscrypt.h
+++ b/include/uapi/linux/fscrypt.h
@@ -26,6 +26,8 @@
#define FSCRYPT_MODE_AES_256_CTS 4
#define FSCRYPT_MODE_AES_128_CBC 5
#define FSCRYPT_MODE_AES_128_CTS 6
+#define FSCRYPT_MODE_SM4_XTS 7
+#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 */
--
2.24.3 (Apple Git-128)
On Tue, Nov 22, 2022 at 03:06:32PM +0800, Tianjia Zhang wrote:
> SM4 is a symmetric algorithm widely used in China, this patch enables
> to use SM4-XTS mode to encrypt file content, and use SM4-CBC-CTS to
> encrypt filename.
>
> Signed-off-by: Tianjia Zhang <[email protected]>
There is still no explanation here about why you believe this algorithm is
useful to support in fscrypt.
- Eric
Hi Eric,
On 11/23/22 3:22 AM, Eric Biggers wrote:
> On Tue, Nov 22, 2022 at 03:06:32PM +0800, Tianjia Zhang wrote:
>> SM4 is a symmetric algorithm widely used in China, this patch enables
>> to use SM4-XTS mode to encrypt file content, and use SM4-CBC-CTS to
>> encrypt filename.
>>
>> Signed-off-by: Tianjia Zhang <[email protected]>
>
> There is still no explanation here about why you believe this algorithm is
> useful to support in fscrypt.
>
> - Eric
Sorry, I will send a new version of patch to add these information.
Best regards,
Tianjia