SM4 is widely used in China's data encryption software and hardware.
these algoritms are mandatory in many scenarios. 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.
v3 change:
- update git commit message
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 is even mandatory
in many scenarios. We need to provide these users with the ability to
encrypt files or disks using SM4-XTS, and many other algorithms that use
SM2/3/4 algorithms or their combined algorithm scenarios, these features
are demanded by many users, 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 Fri, Nov 25, 2022 at 08:16:30PM +0800, Tianjia Zhang wrote:
> 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;
Sorry, one more thing I didn't notice before. Since this is a new feature,
please only allow it in fscrypt_valid_enc_modes_v2(), not in
fscrypt_valid_enc_modes_v1(). That's what we did for AES-256-XTS +
AES-256-HCTR2 recently. There should be no need to add new features to
v1 encryption policies, which have been deprecated for several years.
- Eric
Hi Eric,
On 11/26/22 2:24 AM, Eric Biggers wrote:
> On Fri, Nov 25, 2022 at 08:16:30PM +0800, Tianjia Zhang wrote:
>> 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;
>
> Sorry, one more thing I didn't notice before. Since this is a new feature,
> please only allow it in fscrypt_valid_enc_modes_v2(), not in
> fscrypt_valid_enc_modes_v1(). That's what we did for AES-256-XTS +
> AES-256-HCTR2 recently. There should be no need to add new features to
> v1 encryption policies, which have been deprecated for several years.
>
> - Eric
Thanks for reminder, it makes sense to only support the new algorithm in
v2 policy, which I will do this.
BR,
Tianjia
On 11/25/22 19:16, Tianjia Zhang wrote:
> SM4 is a symmetric algorithm widely used in China, and is even mandatory
> in many scenarios. We need to provide these users with the ability to
> encrypt files or disks using SM4-XTS, and many other algorithms that use
> SM2/3/4 algorithms or their combined algorithm scenarios, these features
> are demanded by many users, this patch enables to use SM4-XTS mode to
> encrypt file content, and use SM4-CBC-CTS to encrypt filename.
>
Similar reply as [1]. That is, better say:
```
Add support for XTS and CTS mode variant of SM4 algorithm, in similar
fashion to SM2 and SM3. The former is used to encrypt file contents, while
the latter (SM4-CBC-CTS) is used to encrypt filenames.
```
Thanks.
[1]: https://lore.kernel.org/linux-doc/[email protected]/
--
An old man doll... just what I always wanted! - Clara
Hi Bagas,
On 11/28/22 9:33 PM, Bagas Sanjaya wrote:
> On 11/25/22 19:16, Tianjia Zhang wrote:
>> SM4 is a symmetric algorithm widely used in China, and is even mandatory
>> in many scenarios. We need to provide these users with the ability to
>> encrypt files or disks using SM4-XTS, and many other algorithms that use
>> SM2/3/4 algorithms or their combined algorithm scenarios, these features
>> are demanded by many users, this patch enables to use SM4-XTS mode to
>> encrypt file content, and use SM4-CBC-CTS to encrypt filename.
>>
>
> Similar reply as [1]. That is, better say:
>
> ```
> Add support for XTS and CTS mode variant of SM4 algorithm, in similar
> fashion to SM2 and SM3. The former is used to encrypt file contents, while
> the latter (SM4-CBC-CTS) is used to encrypt filenames.
> ```
>
> Thanks.
>
> [1]: https://lore.kernel.org/linux-doc/[email protected]/
>
Thanks for your reply, it is very valuable for me, I will update it in
the next patch.
Cheers,
Tianjia