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Feature: Provide sm2 algorithm support(#277)
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This code is to enable tpm2-tss-engine to support the SMx algorithm.

Signed-off-by: bangcheng <[email protected]>
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@bangcheng
bangcheng committed Oct 9, 2023
1 parent af8b26e commit e33231f
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Showing 2 changed files with 72 additions and 4 deletions.
65 changes: 63 additions & 2 deletions src/tpm2-tss-engine-ecc.c
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Original file line number Diff line number Diff line change
Expand Up @@ -54,6 +54,9 @@ EC_KEY_METHOD *ecc_methods = NULL;
#ifdef HAVE_OPENSSL_DIGEST_SIGN
static int (*ecdsa_pkey_orig_copy)(EVP_PKEY_CTX *dst, EVP_PKEY_CTX *src);
static void (*ecdsa_pkey_orig_cleanup)(EVP_PKEY_CTX *ctx);
static int (*sm2_digest_custom_default) (EVP_PKEY_CTX *ctx, EVP_MD_CTX *mctx) = NULL;
static int (*pkey_sm2_sign_default) (EVP_PKEY_CTX *ctx, unsigned char *sig, size_t *siglen,
const unsigned char *tbs, size_t tbslen) = NULL;
#endif /* HAVE_OPENSSL_DIGEST_SIGN */

static TPM2B_DATA allOutsideInfo = {
Expand Down Expand Up @@ -238,7 +241,7 @@ ecdsa_sign(ESYS_CONTEXT *esys_ctx, ESYS_TR key_handle,
TPM2_ALG_ID hash_alg)
{
TPMT_SIG_SCHEME inScheme = {
.scheme = TPM2_ALG_ECDSA,
.scheme = (hash_alg == TPM2_ALG_SM3_256) ? TPM2_ALG_SM2 : TPM2_ALG_ECDSA,
.details.ecdsa.hashAlg = hash_alg,
};
BIGNUM *bns = NULL, *bnr = NULL;
Expand Down Expand Up @@ -360,7 +363,10 @@ ecdsa_ec_key_sign(const unsigned char *dgst, int dgst_len, const BIGNUM *inv,
dgst_len = SHA_DIGEST_LENGTH;
} else if (dgst_len == SHA256_DIGEST_LENGTH ||
(curve_len <= SHA256_DIGEST_LENGTH && dgst_len > SHA256_DIGEST_LENGTH)) {
hash_alg = TPM2_ALG_SHA256;
if (EC_GROUP_get_curve_name(EC_KEY_get0_group(eckey)) == NID_sm2)
hash_alg = TPM2_ALG_SM3_256;
else
hash_alg = TPM2_ALG_SHA256;
dgst_len = SHA256_DIGEST_LENGTH;
} else if (dgst_len == SHA384_DIGEST_LENGTH ||
(curve_len <= SHA384_DIGEST_LENGTH && dgst_len > SHA384_DIGEST_LENGTH)) {
Expand Down Expand Up @@ -516,6 +522,9 @@ populate_ecc(EC_KEY *key)
case TPM2_ECC_NIST_P384:
nid = EC_curve_nist2nid("P-384");
break;
case TPM2_ECC_SM2_P256:
nid = NID_sm2;
break;
default:
nid = -1;
}
Expand Down Expand Up @@ -796,6 +805,42 @@ tpm2tss_ecc_genkey(EC_KEY *key, TPMI_ECC_CURVE curve, const char *password,
return (r == TSS2_RC_SUCCESS);
}

/** Customize the pkey_sm2_sign interface
*
* Customize the pkey_sm2_sign interface. When there is a tpm key extension value, call the ecdsa_ec_key_sign interface to sign.
* @retval 1 on success
* @retval 0 on failure
*/
static int pkey_sm2_sign(EVP_PKEY_CTX *ctx, unsigned char *sig, size_t *siglen,
const unsigned char *tbs, size_t tbslen)
{
EC_KEY *ec = EVP_PKEY_get0_EC_KEY(EVP_PKEY_CTX_get0_pkey(ctx));

if (tpm2tss_ecc_getappdata(ec) == NULL) {
// call pkey_sm2_sign_default
return pkey_sm2_sign_default(ctx, sig, siglen, tbs, tbslen);
}
else {
// call tpm sig function
const int sig_sz = ECDSA_size(ec);
if (sig_sz <= 0) {
return 0;
}
if (sig == NULL) {
*siglen = (size_t)sig_sz;
return 1;
}
if (*siglen < (size_t)sig_sz) return 0;
ECDSA_SIG *sig_res = ecdsa_ec_key_sign(tbs, tbslen, NULL, NULL, ec);
int siglen_temp = i2d_ECDSA_SIG(sig_res, &sig);
ECDSA_SIG_free(sig_res);
if (siglen_temp < 0) return 0;
*siglen = siglen_temp;
}

return 1;
}

/** Initialize the tpm2tss engine's ecc submodule
*
* Initialize the tpm2tss engine's submodule by setting function pointer.
Expand Down Expand Up @@ -869,6 +914,22 @@ init_ecc(ENGINE *e)
EVP_PKEY_meth_set_signctx(pkey_ecc_methods, NULL, ecdsa_signctx);
EVP_PKEY_meth_set_digest_custom(pkey_ecc_methods, ecdsa_digest_custom);
EVP_PKEY_meth_add0(pkey_ecc_methods);

/* add engine for sm2*/
EVP_PKEY_METHOD *pkey_sm2_methods = EVP_PKEY_meth_new(EVP_PKEY_SM2, 0);
if (pkey_sm2_methods == NULL)
return 0;
EVP_PKEY_METHOD *pkey_orig_sm2_methods = EVP_PKEY_meth_find(EVP_PKEY_SM2);
if (pkey_orig_sm2_methods == NULL)
return 0;
EVP_PKEY_meth_copy(pkey_sm2_methods, pkey_orig_sm2_methods);

EVP_PKEY_meth_get_digest_custom(pkey_orig_sm2_methods, &sm2_digest_custom_default);
EVP_PKEY_meth_get_sign(pkey_orig_sm2_methods, NULL, &pkey_sm2_sign_default);

EVP_PKEY_meth_set_digest_custom(pkey_sm2_methods, sm2_digest_custom_default);
EVP_PKEY_meth_set_sign(pkey_sm2_methods, NULL, pkey_sm2_sign);
EVP_PKEY_meth_add0(pkey_sm2_methods);
#endif /* HAVE_OPENSSL_DIGEST_SIGN */

return 1;
Expand Down
11 changes: 9 additions & 2 deletions src/tpm2tss-genkey.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -52,7 +52,7 @@ char *help =
"Arguments:\n"
" <filename> storage for the encrypted private key\n"
"Options:\n"
" -a, --alg public key algorithm (rsa, ecdsa) (default: rsa)\n"
" -a, --alg public key algorithm (rsa, ecdsa, sm2) (default: rsa)\n"
" -c, --curve curve for ecc (default: nist_p256)\n"
" -e, --exponent exponent for rsa (default: 65537)\n"
" -h, --help print help\n"
Expand Down Expand Up @@ -148,6 +148,10 @@ parse_opts(int argc, char **argv)
} else if (strcasecmp(optarg, "ecdsa") == 0) {
opt.alg = TPM2_ALG_ECDSA;
break;
} else if (strcasecmp(optarg, "sm2") == 0) {
opt.alg = TPM2_ALG_ECDSA;
opt.curve = TPM2_ECC_SM2_P256;
break;
} else {
ERR("Unknown algorithm.\n");
exit(1);
Expand Down Expand Up @@ -387,7 +391,10 @@ main(int argc, char **argv)
tpm2Data = genkey_rsa();
break;
case TPM2_ALG_ECDSA:
VERB("Generating the ecdsa key\n");
if (opt.curve == TPM2_ECC_SM2_P256)
VERB("Generating the sm2 key\n");
else
VERB("Generating the ecdsa key\n");
tpm2Data = genkey_ecdsa();
break;
default:
Expand Down

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