[PATCH v6 8/8] integrity: Asymmetric digsig supports SM2-with-SM3 algorithm

[Vitaly Chikunov]

On Thu, Sep 03, 2020 at 09:12:42PM +0800, Tianjia Zhang wrote:
> Asymmetric digsig supports SM2-with-SM3 algorithm combination,
> so that IMA can also verify SM2's signature data.
> 
> Signed-off-by: Tianjia Zhang <tianjia.zhang at linux.alibaba.com>
> Tested-by: Xufeng Zhang <yunbo.xufeng at linux.alibaba.com>
> Reviewed-by: Mimi Zohar <zohar at linux.ibm.com> (coding, not crypto

It looks not breaking ecrdsa/streebog handling and accords to rfc draft:

  https://tools.ietf.org/html/draft-shen-sm2-ecdsa-02

  5.1.4.2.  Hash Functions
    The sm2 digital signature algorithm requires the hash functions
    approved by Chinese Commercial Cryptography Administration Office,
    such as sm3.

Reviewed-by: Vitaly Chikunov <vt at altlinux.org>

Thanks,

> ---
>  security/integrity/digsig_asymmetric.c | 14 +++++++++++---
>  1 file changed, 11 insertions(+), 3 deletions(-)
> 
> diff --git a/security/integrity/digsig_asymmetric.c b/security/integrity/digsig_asymmetric.c
> index cfa4127d0518..b86a4a8f61ab 100644
> --- a/security/integrity/digsig_asymmetric.c
> +++ b/security/integrity/digsig_asymmetric.c
> @@ -99,14 +99,22 @@ int asymmetric_verify(struct key *keyring, const char *sig,
>  	memset(&pks, 0, sizeof(pks));
>  
>  	pks.hash_algo = hash_algo_name[hdr->hash_algo];
> -	if (hdr->hash_algo == HASH_ALGO_STREEBOG_256 ||
> -	    hdr->hash_algo == HASH_ALGO_STREEBOG_512) {
> +	switch (hdr->hash_algo) {
> +	case HASH_ALGO_STREEBOG_256:
> +	case HASH_ALGO_STREEBOG_512:
>  		/* EC-RDSA and Streebog should go together. */
>  		pks.pkey_algo = "ecrdsa";
>  		pks.encoding = "raw";
> -	} else {
> +		break;
> +	case HASH_ALGO_SM3_256:
> +		/* SM2 and SM3 should go together. */
> +		pks.pkey_algo = "sm2";
> +		pks.encoding = "raw";
> +		break;
> +	default:
>  		pks.pkey_algo = "rsa";
>  		pks.encoding = "pkcs1";
> +		break;
>  	}
>  	pks.digest = (u8 *)data;
>  	pks.digest_size = datalen;