/* rsa_ctx_to_pss converts EVP_PKEY_CTX in PSS mode into corresponding
* algorithm parameter, suitable for setting as an AlgorithmIdentifier. */
static ASN1_STRING *rsa_ctx_to_pss(EVP_PKEY_CTX *pkctx) {
const EVP_MD *sigmd, *mgf1md;
RSA_PSS_PARAMS *pss = NULL;
ASN1_STRING *os = NULL;
EVP_PKEY *pk = EVP_PKEY_CTX_get0_pkey(pkctx);
int saltlen, rv = 0;
if (!EVP_PKEY_CTX_get_signature_md(pkctx, &sigmd) ||
!EVP_PKEY_CTX_get_rsa_mgf1_md(pkctx, &mgf1md) ||
!EVP_PKEY_CTX_get_rsa_pss_saltlen(pkctx, &saltlen)) {
goto err;
}
if (saltlen == -1) {
saltlen = EVP_MD_size(sigmd);
} else if (saltlen == -2) {
saltlen = EVP_PKEY_size(pk) - EVP_MD_size(sigmd) - 2;
if (((EVP_PKEY_bits(pk) - 1) & 0x7) == 0) {
saltlen--;
}
} else {
goto err;
}
pss = RSA_PSS_PARAMS_new();
if (!pss) {
goto err;
}
if (saltlen != 20) {
pss->saltLength = ASN1_INTEGER_new();
if (!pss->saltLength ||
!ASN1_INTEGER_set(pss->saltLength, saltlen)) {
goto err;
}
}
if (!rsa_md_to_algor(&pss->hashAlgorithm, sigmd) ||
!rsa_md_to_mgf1(&pss->maskGenAlgorithm, mgf1md)) {
goto err;
}
/* Finally create string with pss parameter encoding. */
if (!ASN1_item_pack(pss, ASN1_ITEM_rptr(RSA_PSS_PARAMS), &os)) {
goto err;
}
rv = 1;
err:
if (pss) {
RSA_PSS_PARAMS_free(pss);
}
if (rv) {
return os;
}
if (os) {
ASN1_STRING_free(os);
}
return NULL;
}
int x509_rsa_ctx_to_pss(EVP_MD_CTX *ctx, X509_ALGOR *algor) {
const EVP_MD *sigmd, *mgf1md;
int saltlen;
if (!EVP_PKEY_CTX_get_signature_md(ctx->pctx, &sigmd) ||
!EVP_PKEY_CTX_get_rsa_mgf1_md(ctx->pctx, &mgf1md) ||
!EVP_PKEY_CTX_get_rsa_pss_saltlen(ctx->pctx, &saltlen)) {
return 0;
}
EVP_PKEY *pk = EVP_PKEY_CTX_get0_pkey(ctx->pctx);
if (saltlen == -1) {
saltlen = EVP_MD_size(sigmd);
} else if (saltlen == -2) {
saltlen = EVP_PKEY_size(pk) - EVP_MD_size(sigmd) - 2;
if (((EVP_PKEY_bits(pk) - 1) & 0x7) == 0) {
saltlen--;
}
} else {
return 0;
}
int ret = 0;
ASN1_STRING *os = NULL;
RSA_PSS_PARAMS *pss = RSA_PSS_PARAMS_new();
if (!pss) {
goto err;
}
if (saltlen != 20) {
pss->saltLength = ASN1_INTEGER_new();
if (!pss->saltLength ||
!ASN1_INTEGER_set(pss->saltLength, saltlen)) {
goto err;
}
}
if (!rsa_md_to_algor(&pss->hashAlgorithm, sigmd) ||
!rsa_md_to_mgf1(&pss->maskGenAlgorithm, mgf1md)) {
goto err;
}
/* Finally create string with pss parameter encoding. */
if (!ASN1_item_pack(pss, ASN1_ITEM_rptr(RSA_PSS_PARAMS), &os)) {
goto err;
}
X509_ALGOR_set0(algor, OBJ_nid2obj(NID_rsassaPss), V_ASN1_SEQUENCE, os);
os = NULL;
ret = 1;
err:
RSA_PSS_PARAMS_free(pss);
ASN1_STRING_free(os);
return ret;
}
static int rsa_pss_to_ctx(EVP_MD_CTX *ctx, EVP_PKEY_CTX *pkctx,
X509_ALGOR *sigalg, EVP_PKEY *pkey)
{
int rv = -1;
int saltlen;
const EVP_MD *mgf1md = NULL, *md = NULL;
RSA_PSS_PARAMS *pss;
/* Sanity check: make sure it is PSS */
if (OBJ_obj2nid(sigalg->algorithm) != EVP_PKEY_RSA_PSS) {
RSAerr(RSA_F_RSA_PSS_TO_CTX, RSA_R_UNSUPPORTED_SIGNATURE_TYPE);
return -1;
}
/* Decode PSS parameters */
pss = rsa_pss_decode(sigalg);
if (!rsa_pss_get_param(pss, &md, &mgf1md, &saltlen)) {
RSAerr(RSA_F_RSA_PSS_TO_CTX, RSA_R_INVALID_PSS_PARAMETERS);
goto err;
}
/* We have all parameters now set up context */
if (pkey) {
if (!EVP_DigestVerifyInit(ctx, &pkctx, md, NULL, pkey))
goto err;
} else {
const EVP_MD *checkmd;
if (EVP_PKEY_CTX_get_signature_md(pkctx, &checkmd) <= 0)
goto err;
if (EVP_MD_type(md) != EVP_MD_type(checkmd)) {
RSAerr(RSA_F_RSA_PSS_TO_CTX, RSA_R_DIGEST_DOES_NOT_MATCH);
goto err;
}
}
if (EVP_PKEY_CTX_set_rsa_padding(pkctx, RSA_PKCS1_PSS_PADDING) <= 0)
goto err;
if (EVP_PKEY_CTX_set_rsa_pss_saltlen(pkctx, saltlen) <= 0)
goto err;
if (EVP_PKEY_CTX_set_rsa_mgf1_md(pkctx, mgf1md) <= 0)
goto err;
/* Carry on */
rv = 1;
err:
RSA_PSS_PARAMS_free(pss);
return rv;
}
static RSA_PSS_PARAMS *rsa_ctx_to_pss(EVP_PKEY_CTX *pkctx)
{
const EVP_MD *sigmd, *mgf1md;
EVP_PKEY *pk = EVP_PKEY_CTX_get0_pkey(pkctx);
int saltlen;
if (EVP_PKEY_CTX_get_signature_md(pkctx, &sigmd) <= 0)
return NULL;
if (EVP_PKEY_CTX_get_rsa_mgf1_md(pkctx, &mgf1md) <= 0)
return NULL;
if (!EVP_PKEY_CTX_get_rsa_pss_saltlen(pkctx, &saltlen))
return NULL;
if (saltlen == -1) {
saltlen = EVP_MD_size(sigmd);
} else if (saltlen == -2) {
saltlen = EVP_PKEY_size(pk) - EVP_MD_size(sigmd) - 2;
if ((EVP_PKEY_bits(pk) & 0x7) == 1)
saltlen--;
}
return rsa_pss_params_create(sigmd, mgf1md, saltlen);
}
static int rsa_pss_to_ctx(EVP_MD_CTX *ctx, EVP_PKEY_CTX *pkctx,
X509_ALGOR *sigalg, EVP_PKEY *pkey)
{
int rv = -1;
int saltlen;
const EVP_MD *mgf1md = NULL, *md = NULL;
RSA_PSS_PARAMS *pss;
X509_ALGOR *maskHash;
/* Sanity check: make sure it is PSS */
if (OBJ_obj2nid(sigalg->algorithm) != NID_rsassaPss) {
RSAerr(RSA_F_RSA_PSS_TO_CTX, RSA_R_UNSUPPORTED_SIGNATURE_TYPE);
return -1;
}
/* Decode PSS parameters */
pss = rsa_pss_decode(sigalg, &maskHash);
if (pss == NULL) {
RSAerr(RSA_F_RSA_PSS_TO_CTX, RSA_R_INVALID_PSS_PARAMETERS);
goto err;
}
mgf1md = rsa_mgf1_to_md(pss->maskGenAlgorithm, maskHash);
if (!mgf1md)
goto err;
md = rsa_algor_to_md(pss->hashAlgorithm);
if (!md)
goto err;
if (pss->saltLength) {
saltlen = ASN1_INTEGER_get(pss->saltLength);
/*
* Could perform more salt length sanity checks but the main RSA
* routines will trap other invalid values anyway.
*/
if (saltlen < 0) {
RSAerr(RSA_F_RSA_PSS_TO_CTX, RSA_R_INVALID_SALT_LENGTH);
goto err;
}
} else
saltlen = 20;
/*
* low-level routines support only trailer field 0xbc (value 1) and
* PKCS#1 says we should reject any other value anyway.
*/
if (pss->trailerField && ASN1_INTEGER_get(pss->trailerField) != 1) {
RSAerr(RSA_F_RSA_PSS_TO_CTX, RSA_R_INVALID_TRAILER);
goto err;
}
/* We have all parameters now set up context */
if (pkey) {
if (!EVP_DigestVerifyInit(ctx, &pkctx, md, NULL, pkey))
goto err;
} else {
const EVP_MD *checkmd;
if (EVP_PKEY_CTX_get_signature_md(pkctx, &checkmd) <= 0)
goto err;
if (EVP_MD_type(md) != EVP_MD_type(checkmd)) {
RSAerr(RSA_F_RSA_PSS_TO_CTX, RSA_R_DIGEST_DOES_NOT_MATCH);
goto err;
}
}
if (EVP_PKEY_CTX_set_rsa_padding(pkctx, RSA_PKCS1_PSS_PADDING) <= 0)
goto err;
if (EVP_PKEY_CTX_set_rsa_pss_saltlen(pkctx, saltlen) <= 0)
goto err;
if (EVP_PKEY_CTX_set_rsa_mgf1_md(pkctx, mgf1md) <= 0)
goto err;
/* Carry on */
rv = 1;
err:
RSA_PSS_PARAMS_free(pss);
X509_ALGOR_free(maskHash);
return rv;
}
