Re: [PATCH ima-evm-utils v2] ima-evm-utils: Support SM2 algorithm for sign and verify

[Tianjia Zhang <tianjia.zhang@linux.alibaba.com>]

On 2/18/21 10:06 PM, Mimi Zohar wrote:
> Hi Tianjia,
> 
> On Thu, 2021-02-11 at 13:22 +0800, Tianjia Zhang wrote:
>> The combination of SM2 and SM3 algorithms has been implemented in the
>> kernel. At present, the ima-evm-utils signature tool does not support
>> this combination of algorithms. Because in the current version of
>> OpenSSL 1.1.1, the SM2 algorithm and the public key using the EC
>> algorithm share the same ID 'EVP_PKEY_EC', and the specific algorithm
>> can only be distinguished by the curve name used. This patch supports
>> this feature.
>>
>> Signed-off-by: Tianjia Zhang <tianjia.zhang@linux.alibaba.com>
>> ---
>>   src/libimaevm.c | 20 ++++++++++++++++++++
>>   1 file changed, 20 insertions(+)
>>
>> diff --git a/src/libimaevm.c b/src/libimaevm.c
>> index fa6c278..589dd09 100644
>> --- a/src/libimaevm.c
>> +++ b/src/libimaevm.c
>> @@ -518,6 +518,16 @@ static int verify_hash_v2(const char *file, const unsigned char *hash, int size,
>>   		return -1;
>>   	}
>>   
>> +#ifdef EVP_PKEY_SM2
>> +	/* If EC key are used, check whether it is SM2 key */
>> +	if (EVP_PKEY_id(pkey) == EVP_PKEY_EC) {
>> +		EC_KEY *ec = EVP_PKEY_get0_EC_KEY(pkey);
>> +		int curve = EC_GROUP_get_curve_name(EC_KEY_get0_group(ec));
>> +		if (curve == NID_sm2)
>> +			EVP_PKEY_set_alias_type(pkey, EVP_PKEY_SM2);
>> +	}
>> +#endif
>> +
> 
> Suppose a file is signed on one system and verified on another.  What
> happens if EVP_PKEY_SM2 is defined on one system, but not the other?
> Since the signing/verifying code do exactly the same thing, a
> sign_verify test wouldn't detect the problem.   In anycase, please
> define a sign_verify test.
> 
> thanks,
> 
> Mimi
> 
> 

Sorry for the late reply.

This will cause verify to fail, I will add some sm2 tests in the next patch.

Best regards,
Tianjia