static int rsa_sig_info_set(X509_SIG_INFO *siginf, const X509_ALGOR *sigalg,
const ASN1_STRING *sig)
{
int rv = 0;
int mdnid, saltlen;
uint32_t flags;
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)
return 0;
/* Decode PSS parameters */
pss = rsa_pss_decode(sigalg);
if (!rsa_pss_get_param(pss, &md, &mgf1md, &saltlen))
goto err;
mdnid = EVP_MD_type(md);
/*
* For TLS need SHA256, SHA384 or SHA512, digest and MGF1 digest must
* match and salt length must equal digest size
*/
if ((mdnid == NID_sha256 || mdnid == NID_sha384 || mdnid == NID_sha512)
&& mdnid == EVP_MD_type(mgf1md) && saltlen == EVP_MD_size(md))
flags = X509_SIG_INFO_TLS;
else
flags = 0;
/* Note: security bits half number of digest bits */
X509_SIG_INFO_set(siginf, mdnid, EVP_PKEY_RSA_PSS, EVP_MD_size(md) * 4,
flags);
rv = 1;
err:
RSA_PSS_PARAMS_free(pss);
return rv;
}
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 int pkey_pss_init(EVP_PKEY_CTX *ctx)
{
RSA *rsa;
RSA_PKEY_CTX *rctx = ctx->data;
const EVP_MD *md;
const EVP_MD *mgf1md;
int min_saltlen, max_saltlen;
/* Should never happen */
if (!pkey_ctx_is_pss(ctx))
return 0;
rsa = ctx->pkey->pkey.rsa;
/* If no restrictions just return */
if (rsa->pss == NULL)
return 1;
/* Get and check parameters */
if (!rsa_pss_get_param(rsa->pss, &md, &mgf1md, &min_saltlen))
return 0;
/* See if minumum salt length exceeds maximum possible */
max_saltlen = RSA_size(rsa) - EVP_MD_size(md);
if ((RSA_bits(rsa) & 0x7) == 1)
max_saltlen--;
if (min_saltlen > max_saltlen) {
RSAerr(RSA_F_PKEY_PSS_INIT, RSA_R_INVALID_SALT_LENGTH);
return 0;
}
rctx->min_saltlen = min_saltlen;
/*
* Set PSS restrictions as defaults: we can then block any attempt to
* use invalid values in pkey_rsa_ctrl
*/
rctx->md = md;
rctx->mgf1md = mgf1md;
rctx->saltlen = min_saltlen;
return 1;
}
