/* $OpenBSD: rsa_ameth.c,v 1.65 2026/04/07 13:16:41 tb Exp $ */
/* Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL
 * project 2006.
 */
/* ====================================================================
 * Copyright (c) 2006 The OpenSSL Project.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. All advertising materials mentioning features or use of this
 *    software must display the following acknowledgment:
 *    "This product includes software developed by the OpenSSL Project
 *    for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
 *
 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
 *    endorse or promote products derived from this software without
 *    prior written permission. For written permission, please contact
 *    licensing@OpenSSL.org.
 *
 * 5. Products derived from this software may not be called "OpenSSL"
 *    nor may "OpenSSL" appear in their names without prior written
 *    permission of the OpenSSL Project.
 *
 * 6. Redistributions of any form whatsoever must retain the following
 *    acknowledgment:
 *    "This product includes software developed by the OpenSSL Project
 *    for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
 *
 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 * OF THE POSSIBILITY OF SUCH DAMAGE.
 * ====================================================================
 *
 * This product includes cryptographic software written by Eric Young
 * (eay@cryptsoft.com).  This product includes software written by Tim
 * Hudson (tjh@cryptsoft.com).
 *
 */

#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include <openssl/opensslconf.h>

#include <openssl/asn1.h>
#include <openssl/bio.h>
#include <openssl/bn.h>
#include <openssl/cms.h>
#include <openssl/evp.h>
#include <openssl/objects.h>
#include <openssl/pkcs7.h>
#include <openssl/rsa.h>
#include <openssl/sha.h>
#include <openssl/x509.h>

#include "asn1_local.h"
#include "bn_local.h"
#include "err_local.h"
#include "evp_local.h"
#include "rsa_local.h"
#include "x509_local.h"

#ifndef OPENSSL_NO_CMS
static int rsa_cms_sign(CMS_SignerInfo *si);
static int rsa_cms_verify(CMS_SignerInfo *si);
static int rsa_cms_decrypt(CMS_RecipientInfo *ri);
static int rsa_cms_encrypt(CMS_RecipientInfo *ri);
#endif

static RSA_PSS_PARAMS *rsa_pss_decode(const X509_ALGOR *alg);

static int rsa_alg_set_pkcs1_padding(X509_ALGOR *alg);

/* Set any parameters associated with pkey */
static int
rsa_param_encode(const EVP_PKEY *pkey, ASN1_STRING **pstr, int *pstrtype)
{
        const RSA *rsa = pkey->pkey.rsa;

        *pstr = NULL;

        /* If RSA it's just NULL type */
        if (pkey->ameth->pkey_id != EVP_PKEY_RSA_PSS) {
                *pstrtype = V_ASN1_NULL;
                return 1;
        }

        /* If no PSS parameters we omit parameters entirely */
        if (rsa->pss == NULL) {
                *pstrtype = V_ASN1_UNDEF;
                return 1;
        }

        /* Encode PSS parameters */
        if (ASN1_item_pack(rsa->pss, &RSA_PSS_PARAMS_it, pstr) == NULL)
                return 0;

        *pstrtype = V_ASN1_SEQUENCE;
        return 1;
}

/* Decode any parameters and set them in RSA structure */
static int
rsa_param_decode(RSA *rsa, const X509_ALGOR *alg)
{
        const ASN1_OBJECT *algoid;
        const void *algp;
        int algptype;

        X509_ALGOR_get0(&algoid, &algptype, &algp, alg);
        if (OBJ_obj2nid(algoid) != EVP_PKEY_RSA_PSS)
                return 1;
        if (algptype == V_ASN1_UNDEF)
                return 1;
        if (algptype != V_ASN1_SEQUENCE) {
                RSAerror(RSA_R_INVALID_PSS_PARAMETERS);
                return 0;
        }
        rsa->pss = rsa_pss_decode(alg);
        if (rsa->pss == NULL)
                return 0;
        return 1;
}

static int
rsa_pub_encode(X509_PUBKEY *pk, const EVP_PKEY *pkey)
{
        ASN1_STRING *str = NULL;
        int strtype;
        unsigned char *penc = NULL;
        int penclen = 0;
        ASN1_OBJECT *aobj;

        if (!rsa_param_encode(pkey, &str, &strtype))
                goto err;
        if ((penclen = i2d_RSAPublicKey(pkey->pkey.rsa, &penc)) <= 0) {
                penclen = 0;
                goto err;
        }
        if ((aobj = OBJ_nid2obj(pkey->ameth->pkey_id)) == NULL)
                goto err;
        if (!X509_PUBKEY_set0_param(pk, aobj, strtype, str, penc, penclen))
                goto err;

        return 1;

 err:
        ASN1_STRING_free(str);
        freezero(penc, penclen);

        return 0;
}

static int
rsa_pub_decode(EVP_PKEY *pkey, X509_PUBKEY *pubkey)
{
        const unsigned char *p;
        int pklen;
        X509_ALGOR *alg;
        RSA *rsa = NULL;

        if (!X509_PUBKEY_get0_param(NULL, &p, &pklen, &alg, pubkey))
                return 0;
        if ((rsa = d2i_RSAPublicKey(NULL, &p, pklen)) == NULL) {
                RSAerror(ERR_R_RSA_LIB);
                return 0;
        }
        if (!rsa_param_decode(rsa, alg)) {
                RSA_free(rsa);
                return 0;
        }
        if (!EVP_PKEY_assign(pkey, pkey->ameth->pkey_id, rsa)) {
                RSA_free(rsa);
                return 0;
        }
        return 1;
}

static int
rsa_pub_cmp(const EVP_PKEY *a, const EVP_PKEY *b)
{
        if (BN_cmp(b->pkey.rsa->n, a->pkey.rsa->n) != 0 ||
            BN_cmp(b->pkey.rsa->e, a->pkey.rsa->e) != 0)
                return 0;

        return 1;
}

static int
old_rsa_priv_decode(EVP_PKEY *pkey, const unsigned char **pder, int derlen)
{
        RSA *rsa;
        int ret = 0;

        if ((rsa = d2i_RSAPrivateKey(NULL, pder, derlen)) == NULL) {
                RSAerror(ERR_R_RSA_LIB);
                goto err;
        }
        if (!EVP_PKEY_assign(pkey, pkey->ameth->pkey_id, rsa))
                goto err;
        rsa = NULL;

        ret = 1;

 err:
        RSA_free(rsa);

        return ret;
}

static int
old_rsa_priv_encode(const EVP_PKEY *pkey, unsigned char **pder)
{
        return i2d_RSAPrivateKey(pkey->pkey.rsa, pder);
}

static int
rsa_priv_encode(PKCS8_PRIV_KEY_INFO *p8, const EVP_PKEY *pkey)
{
        ASN1_STRING *str = NULL;
        ASN1_OBJECT *aobj;
        int strtype;
        unsigned char *rk = NULL;
        int rklen = 0;

        if (!rsa_param_encode(pkey, &str, &strtype))
                goto err;
        if ((rklen = i2d_RSAPrivateKey(pkey->pkey.rsa, &rk)) <= 0) {
                RSAerror(ERR_R_MALLOC_FAILURE);
                rklen = 0;
                goto err;
        }
        if ((aobj = OBJ_nid2obj(pkey->ameth->pkey_id)) == NULL)
                goto err;
        if (!PKCS8_pkey_set0(p8, aobj, 0, strtype, str, rk, rklen)) {
                RSAerror(ERR_R_MALLOC_FAILURE);
                goto err;
        }

        return 1;

 err:
        ASN1_STRING_free(str);
        freezero(rk, rklen);

        return 0;
}

static int
rsa_priv_decode(EVP_PKEY *pkey, const PKCS8_PRIV_KEY_INFO *p8)
{
        const unsigned char *p;
        RSA *rsa = NULL;
        int pklen;
        const X509_ALGOR *alg;
        int ret = 0;

        if (!PKCS8_pkey_get0(NULL, &p, &pklen, &alg, p8))
                goto err;
        if ((rsa = d2i_RSAPrivateKey(NULL, &p, pklen)) == NULL)
                goto err;
        if (!rsa_param_decode(rsa, alg))
                goto err;
        if (!EVP_PKEY_assign(pkey, pkey->ameth->pkey_id, rsa))
                goto err;
        rsa = NULL;

        ret = 1;

 err:
        RSA_free(rsa);

        return ret;
}

static int
rsa_size(const EVP_PKEY *pkey)
{
        return RSA_size(pkey->pkey.rsa);
}

static int
rsa_bits(const EVP_PKEY *pkey)
{
        return BN_num_bits(pkey->pkey.rsa->n);
}

static int
rsa_security_bits(const EVP_PKEY *pkey)
{
        return RSA_security_bits(pkey->pkey.rsa);
}

static void
rsa_free(EVP_PKEY *pkey)
{
        RSA_free(pkey->pkey.rsa);
}

static X509_ALGOR *
rsa_mgf1_decode(X509_ALGOR *alg)
{
        if (OBJ_obj2nid(alg->algorithm) != NID_mgf1)
                return NULL;

        return ASN1_TYPE_unpack_sequence(&X509_ALGOR_it, alg->parameter);
}

static RSA_PSS_PARAMS *
rsa_pss_decode(const X509_ALGOR *alg)
{
        RSA_PSS_PARAMS *pss;

        pss = ASN1_TYPE_unpack_sequence(&RSA_PSS_PARAMS_it, alg->parameter);
        if (pss == NULL)
                return NULL;

        if (pss->maskGenAlgorithm != NULL) {
                pss->maskHash = rsa_mgf1_decode(pss->maskGenAlgorithm);
                if (pss->maskHash == NULL) {
                        RSA_PSS_PARAMS_free(pss);
                        return NULL;
                }
        }

        return pss;
}

static int
rsa_pss_param_print(BIO *bp, int pss_key, RSA_PSS_PARAMS *pss, int indent)
{
        int rv = 0;
        X509_ALGOR *maskHash = NULL;

        if (!BIO_indent(bp, indent, 128))
                goto err;
        if (pss_key) {
                if (pss == NULL) {
                        if (BIO_puts(bp, "No PSS parameter restrictions\n") <= 0)
                                return 0;
                        return 1;
                } else {
                        if (BIO_puts(bp, "PSS parameter restrictions:") <= 0)
                                return 0;
                }
        } else if (pss == NULL) {
                if (BIO_puts(bp,"(INVALID PSS PARAMETERS)\n") <= 0)
                        return 0;
                return 1;
        }
        if (BIO_puts(bp, "\n") <= 0)
                goto err;
        if (pss_key)
                indent += 2;
        if (!BIO_indent(bp, indent, 128))
                goto err;
        if (BIO_puts(bp, "Hash Algorithm: ") <= 0)
                goto err;

        if (pss->hashAlgorithm) {
                if (i2a_ASN1_OBJECT(bp, pss->hashAlgorithm->algorithm) <= 0)
                        goto err;
        } else if (BIO_puts(bp, "sha1 (default)") <= 0) {
                goto err;
        }

        if (BIO_puts(bp, "\n") <= 0)
                goto err;

        if (!BIO_indent(bp, indent, 128))
                goto err;

        if (BIO_puts(bp, "Mask Algorithm: ") <= 0)
                goto err;
        if (pss->maskGenAlgorithm) {
                if (i2a_ASN1_OBJECT(bp, pss->maskGenAlgorithm->algorithm) <= 0)
                        goto err;
                if (BIO_puts(bp, " with ") <= 0)
                        goto err;
                maskHash = rsa_mgf1_decode(pss->maskGenAlgorithm);
                if (maskHash != NULL) {
                        if (i2a_ASN1_OBJECT(bp, maskHash->algorithm) <= 0)
                                goto err;
                } else if (BIO_puts(bp, "INVALID") <= 0) {
                        goto err;
                }
        } else if (BIO_puts(bp, "mgf1 with sha1 (default)") <= 0) {
                goto err;
        }
        BIO_puts(bp, "\n");

        if (!BIO_indent(bp, indent, 128))
                goto err;
        if (BIO_printf(bp, "%s Salt Length: 0x", pss_key ? "Minimum" : "") <= 0)
                goto err;
        if (pss->saltLength) {
                if (i2a_ASN1_INTEGER(bp, pss->saltLength) <= 0)
                        goto err;
        } else if (BIO_puts(bp, "14 (default)") <= 0) {
                goto err;
        }
        BIO_puts(bp, "\n");

        if (!BIO_indent(bp, indent, 128))
                goto err;
        if (BIO_puts(bp, "Trailer Field: 0x") <= 0)
                goto err;
        if (pss->trailerField) {
                if (i2a_ASN1_INTEGER(bp, pss->trailerField) <= 0)
                        goto err;
        } else if (BIO_puts(bp, "BC (default)") <= 0) {
                goto err;
        }
        BIO_puts(bp, "\n");

        rv = 1;

 err:
        X509_ALGOR_free(maskHash);
        return rv;

}

static int
pkey_rsa_print(BIO *bp, const EVP_PKEY *pkey, int off, int priv)
{
        const RSA *x = pkey->pkey.rsa;
        char *str;
        const char *s;
        int ret = 0, mod_len = 0;

        if (x->n != NULL)
                mod_len = BN_num_bits(x->n);

        if (!BIO_indent(bp, off, 128))
                goto err;

        if (BIO_printf(bp, "%s ",
            pkey->ameth->pkey_id == EVP_PKEY_RSA_PSS ? "RSA-PSS" : "RSA") <= 0)
                goto err;

        if (priv && x->d != NULL) {
                if (BIO_printf(bp, "Private-Key: (%d bit)\n", mod_len) <= 0)
                        goto err;
                str = "modulus:";
                s = "publicExponent:";
        } else {
                if (BIO_printf(bp, "Public-Key: (%d bit)\n", mod_len) <= 0)
                        goto err;
                str = "Modulus:";
                s = "Exponent:";
        }
        if (!bn_printf(bp, x->n, off, "%s", str))
                goto err;
        if (!bn_printf(bp, x->e, off, "%s", s))
                goto err;
        if (priv) {
                if (!bn_printf(bp, x->d, off, "privateExponent:"))
                        goto err;
                if (!bn_printf(bp, x->p, off, "prime1:"))
                        goto err;
                if (!bn_printf(bp, x->q, off, "prime2:"))
                        goto err;
                if (!bn_printf(bp, x->dmp1, off, "exponent1:"))
                        goto err;
                if (!bn_printf(bp, x->dmq1, off, "exponent2:"))
                        goto err;
                if (!bn_printf(bp, x->iqmp, off, "coefficient:"))
                        goto err;
        }
        if (pkey->ameth->pkey_id == EVP_PKEY_RSA_PSS &&
            !rsa_pss_param_print(bp, 1, x->pss, off))
                goto err;
        ret = 1;
 err:
        return ret;
}

static int
rsa_pub_print(BIO *bp, const EVP_PKEY *pkey, int indent, ASN1_PCTX *ctx)
{
        return pkey_rsa_print(bp, pkey, indent, 0);
}

static int
rsa_priv_print(BIO *bp, const EVP_PKEY *pkey, int indent, ASN1_PCTX *ctx)
{
        return pkey_rsa_print(bp, pkey, indent, 1);
}

static int
rsa_sig_print(BIO *bp, const X509_ALGOR *sigalg, const ASN1_STRING *sig,
    int indent, ASN1_PCTX *pctx)
{
        if (OBJ_obj2nid(sigalg->algorithm) == EVP_PKEY_RSA_PSS) {
                int rv;
                RSA_PSS_PARAMS *pss = rsa_pss_decode(sigalg);

                rv = rsa_pss_param_print(bp, 0, pss, indent);
                RSA_PSS_PARAMS_free(pss);
                if (!rv)
                        return 0;
        } else if (!sig && BIO_puts(bp, "\n") <= 0) {
                return 0;
        }
        if (sig)
                return X509_signature_dump(bp, sig, indent);
        return 1;
}

static int
rsa_pkey_ctrl(EVP_PKEY *pkey, int op, long arg1, void *arg2)
{
        X509_ALGOR *alg = NULL;
        const EVP_MD *md;
        const EVP_MD *mgf1md;
        int min_saltlen;

        switch (op) {
        case ASN1_PKEY_CTRL_PKCS7_SIGN:
                if (arg1 == 0)
                        PKCS7_SIGNER_INFO_get0_algs(arg2, NULL, NULL, &alg);
                break;

        case ASN1_PKEY_CTRL_PKCS7_ENCRYPT:
                if (pkey->ameth->pkey_id == EVP_PKEY_RSA_PSS)
                        return -2;
                if (arg1 == 0)
                        PKCS7_RECIP_INFO_get0_alg(arg2, &alg);
                break;
#ifndef OPENSSL_NO_CMS
        case ASN1_PKEY_CTRL_CMS_SIGN:
                if (arg1 == 0)
                        return rsa_cms_sign(arg2);
                else if (arg1 == 1)
                        return rsa_cms_verify(arg2);
                break;

        case ASN1_PKEY_CTRL_CMS_ENVELOPE:
                if (pkey->ameth->pkey_id == EVP_PKEY_RSA_PSS)
                        return -2;
                if (arg1 == 0)
                        return rsa_cms_encrypt(arg2);
                else if (arg1 == 1)
                        return rsa_cms_decrypt(arg2);
                break;

        case ASN1_PKEY_CTRL_CMS_RI_TYPE:
                if (pkey->ameth->pkey_id == EVP_PKEY_RSA_PSS)
                        return -2;
                *(int *)arg2 = CMS_RECIPINFO_TRANS;
                return 1;
#endif

        case ASN1_PKEY_CTRL_DEFAULT_MD_NID:
                if (pkey->pkey.rsa->pss != NULL) {
                        if (!rsa_pss_get_param(pkey->pkey.rsa->pss, &md, &mgf1md,
                            &min_saltlen)) {
                                RSAerror(ERR_R_INTERNAL_ERROR);
                                return 0;
                        }
                        *(int *)arg2 = EVP_MD_type(md);
                        /* Return of 2 indicates this MD is mandatory */
                        return 2;
                }
                *(int *)arg2 = NID_sha256;
                return 1;

        default:
                return -2;
        }

        if (alg != NULL)
                return rsa_alg_set_pkcs1_padding(alg);

        return 1;
}

static int
rsa_md_to_algor(const EVP_MD *md, X509_ALGOR **out_alg)
{
        X509_ALGOR *alg = NULL;
        int ret = 0;

        X509_ALGOR_free(*out_alg);
        *out_alg = NULL;

        /* RFC 8017 - default hash is SHA-1 and hence omitted. */
        if (md == NULL || EVP_MD_type(md) == NID_sha1)
                goto done;

        if ((alg = X509_ALGOR_new()) == NULL)
                goto err;
        /*
         * XXX - This omits the parameters, whereas RFC 4055, section 2.1
         * explicitly states that an explicit ASN.1 NULL is required.
         */
        if (!X509_ALGOR_set_evp_md(alg, md))
                goto err;

 done:
        *out_alg = alg;
        alg = NULL;

        ret = 1;

 err:
        X509_ALGOR_free(alg);

        return ret;
}

/*
 * RFC 8017, A.2.1 and A.2.3 - encode maskGenAlgorithm for RSAES-OAEP
 * and RSASSA-PSS. The default is mgfSHA1 and hence omitted.
 */
static int
rsa_mgf1md_to_maskGenAlgorithm(const EVP_MD *mgf1md, X509_ALGOR **out_alg)
{
        X509_ALGOR *alg = NULL;
        X509_ALGOR *inner_alg = NULL;
        ASN1_STRING *astr = NULL;
        int ret = 0;

        X509_ALGOR_free(*out_alg);
        *out_alg = NULL;

        if (mgf1md == NULL || EVP_MD_type(mgf1md) == NID_sha1)
                goto done;

        if ((inner_alg = X509_ALGOR_new()) == NULL)
                goto err;
        /*
         * XXX - This omits the parameters, whereas RFC 4055, section 2.1
         * explicitly states that an explicit ASN.1 NULL is required.
         */
        if (!X509_ALGOR_set_evp_md(inner_alg, mgf1md))
                goto err;
        if ((astr = ASN1_item_pack(inner_alg, &X509_ALGOR_it, NULL)) == NULL)
                goto err;

        if ((alg = X509_ALGOR_new()) == NULL)
                goto err;
        if (!X509_ALGOR_set0_by_nid(alg, NID_mgf1, V_ASN1_SEQUENCE, astr))
                goto err;
        astr = NULL;

 done:
        *out_alg = alg;
        alg = NULL;

        ret = 1;

 err:
        X509_ALGOR_free(alg);
        X509_ALGOR_free(inner_alg);
        ASN1_STRING_free(astr);

        return ret;
}

/* Convert algorithm ID to EVP_MD, defaults to SHA1. */
static const EVP_MD *
rsa_algor_to_md(X509_ALGOR *alg)
{
        const EVP_MD *md;

        if (!alg)
                return EVP_sha1();
        md = EVP_get_digestbyobj(alg->algorithm);
        if (md == NULL)
                RSAerror(RSA_R_UNKNOWN_DIGEST);
        return md;
}

/*
 * Convert EVP_PKEY_CTX in PSS mode into corresponding algorithm parameter,
 * suitable for setting an AlgorithmIdentifier.
 */
static RSA_PSS_PARAMS *
rsa_ctx_to_pss(EVP_PKEY_CTX *pkey_ctx)
{
        const EVP_MD *sigmd, *mgf1md;
        EVP_PKEY *pk = EVP_PKEY_CTX_get0_pkey(pkey_ctx);
        int saltlen;

        if (EVP_PKEY_CTX_get_signature_md(pkey_ctx, &sigmd) <= 0)
                return NULL;
        if (EVP_PKEY_CTX_get_rsa_mgf1_md(pkey_ctx, &mgf1md) <= 0)
                return NULL;
        if (!EVP_PKEY_CTX_get_rsa_pss_saltlen(pkey_ctx, &saltlen))
                return NULL;
        if (saltlen == -1) {
                saltlen = EVP_MD_size(sigmd);
        } else if (saltlen == -2 || saltlen == -3) {
                saltlen = EVP_PKEY_size(pk) - EVP_MD_size(sigmd) - 2;
                if ((EVP_PKEY_bits(pk) & 0x7) == 1)
                        saltlen--;
                if (saltlen < 0)
                        return NULL;
        }

        return rsa_pss_params_create(sigmd, mgf1md, saltlen);
}

RSA_PSS_PARAMS *
rsa_pss_params_create(const EVP_MD *sigmd, const EVP_MD *mgf1md, int saltlen)
{
        RSA_PSS_PARAMS *pss = NULL;

        if (mgf1md == NULL)
                mgf1md = sigmd;

        if ((pss = RSA_PSS_PARAMS_new()) == NULL)
                goto err;

        if (!rsa_md_to_algor(sigmd, &pss->hashAlgorithm))
                goto err;
        if (!rsa_mgf1md_to_maskGenAlgorithm(mgf1md, &pss->maskGenAlgorithm))
                goto err;

        /* Translate mgf1md to X509_ALGOR in decoded form for internal use. */
        if (!rsa_md_to_algor(mgf1md, &pss->maskHash))
                goto err;

        /* RFC 8017, A.2.3 - default saltLength is SHA_DIGEST_LENGTH. */
        if (saltlen != SHA_DIGEST_LENGTH) {
                if ((pss->saltLength = ASN1_INTEGER_new()) == NULL)
                        goto err;
                if (!ASN1_INTEGER_set(pss->saltLength, saltlen))
                        goto err;
        }

        return pss;

 err:
        RSA_PSS_PARAMS_free(pss);

        return NULL;
}

/*
 * From PSS AlgorithmIdentifier set public key parameters. If pkey isn't NULL
 * then the EVP_MD_CTX is setup and initialised. If it is NULL parameters are
 * passed to pkey_ctx instead.
 */

static int
rsa_pss_to_ctx(EVP_MD_CTX *ctx, EVP_PKEY_CTX *pkey_ctx,
    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) {
                RSAerror(RSA_R_UNSUPPORTED_SIGNATURE_TYPE);
                return -1;
        }
        /* Decode PSS parameters */
        pss = rsa_pss_decode(sigalg);

        if (!rsa_pss_get_param(pss, &md, &mgf1md, &saltlen)) {
                RSAerror(RSA_R_INVALID_PSS_PARAMETERS);
                goto err;
        }

        /* We have all parameters now set up context */
        if (pkey) {
                if (!EVP_DigestVerifyInit(ctx, &pkey_ctx, md, NULL, pkey))
                        goto err;
        } else {
                const EVP_MD *checkmd;
                if (EVP_PKEY_CTX_get_signature_md(pkey_ctx, &checkmd) <= 0)
                        goto err;
                if (EVP_MD_type(md) != EVP_MD_type(checkmd)) {
                        RSAerror(RSA_R_DIGEST_DOES_NOT_MATCH);
                        goto err;
                }
        }

        if (EVP_PKEY_CTX_set_rsa_padding(pkey_ctx, RSA_PKCS1_PSS_PADDING) <= 0)
                goto err;

        if (EVP_PKEY_CTX_set_rsa_pss_saltlen(pkey_ctx, saltlen) <= 0)
                goto err;

        if (EVP_PKEY_CTX_set_rsa_mgf1_md(pkey_ctx, mgf1md) <= 0)
                goto err;
        /* Carry on */
        rv = 1;

 err:
        RSA_PSS_PARAMS_free(pss);
        return rv;
}

int
rsa_pss_get_param(const RSA_PSS_PARAMS *pss, const EVP_MD **pmd,
    const EVP_MD **pmgf1md, int *psaltlen)
{
        if (pss == NULL)
                return 0;
        *pmd = rsa_algor_to_md(pss->hashAlgorithm);
        if (*pmd == NULL)
                return 0;
        *pmgf1md = rsa_algor_to_md(pss->maskHash);
        if (*pmgf1md == NULL)
                return 0;
        if (pss->saltLength) {
                *psaltlen = ASN1_INTEGER_get(pss->saltLength);
                if (*psaltlen < 0) {
                        RSAerror(RSA_R_INVALID_SALT_LENGTH);
                        return 0;
                }
        } else {
                *psaltlen = 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) {
                RSAerror(RSA_R_INVALID_TRAILER);
                return 0;
        }

        return 1;
}

static int
rsa_pss_signature_info(const X509_ALGOR *alg, int *out_md_nid,
    int *out_pkey_nid, int *out_security_bits, uint32_t *out_flags)
{
        RSA_PSS_PARAMS *pss = NULL;
        const ASN1_OBJECT *aobj;
        const EVP_MD *md, *mgf1md;
        int md_len, salt_len;
        int md_nid = NID_undef, pkey_nid = NID_undef;
        int security_bits = -1;
        uint32_t flags = 0;

        X509_ALGOR_get0(&aobj, NULL, NULL, alg);
        if (OBJ_obj2nid(aobj) != EVP_PKEY_RSA_PSS)
                goto err;

        if ((pss = rsa_pss_decode(alg)) == NULL)
                goto err;
        if (!rsa_pss_get_param(pss, &md, &mgf1md, &salt_len))
                goto err;

        if ((md_nid = EVP_MD_type(md)) == NID_undef)
                goto err;
        if ((md_len = EVP_MD_size(md)) <= 0)
                goto err;

        /*
         * RFC 8446, section 4.2.3 - restricts the digest algorithm:
         * - it must be one of SHA256, SHA384, and SHA512;
         * - the same digest must be used in the mask generation function;
         * - the salt length must match the output length of the digest.
         * XXX - consider separate flags for these checks.
         */
        if (md_nid == NID_sha256 || md_nid == NID_sha384 || md_nid == NID_sha512) {
                if (md_nid == EVP_MD_type(mgf1md) && salt_len == md_len)
                        flags |= X509_SIG_INFO_TLS;
        }

        security_bits = md_len * 4;
        flags |= X509_SIG_INFO_VALID;

        *out_md_nid = md_nid;
        *out_pkey_nid = pkey_nid;
        *out_security_bits = security_bits;
        *out_flags = flags;

 err:
        RSA_PSS_PARAMS_free(pss);

        return (flags & X509_SIG_INFO_VALID) != 0;
}

#ifndef OPENSSL_NO_CMS
static int
rsa_cms_verify(CMS_SignerInfo *si)
{
        int nid, nid2;
        X509_ALGOR *alg;
        EVP_PKEY_CTX *pkey_ctx = CMS_SignerInfo_get0_pkey_ctx(si);

        CMS_SignerInfo_get0_algs(si, NULL, NULL, NULL, &alg);
        nid = OBJ_obj2nid(alg->algorithm);
        if (nid == EVP_PKEY_RSA_PSS)
                return rsa_pss_to_ctx(NULL, pkey_ctx, alg, NULL);
        /* Only PSS allowed for PSS keys */
        if (pkey_ctx->pmeth->pkey_id == EVP_PKEY_RSA_PSS) {
                RSAerror(RSA_R_ILLEGAL_OR_UNSUPPORTED_PADDING_MODE);
                return 0;
        }
        if (nid == NID_rsaEncryption)
                return 1;
        /* Workaround for some implementation that use a signature OID */
        if (OBJ_find_sigid_algs(nid, NULL, &nid2)) {
                if (nid2 == NID_rsaEncryption)
                        return 1;
        }
        return 0;
}
#endif

/*
 * Customised RSA item verification routine. This is called when a signature
 * is encountered requiring special handling. We currently only handle PSS.
 */
static int
rsa_item_verify(EVP_MD_CTX *ctx, const ASN1_ITEM *it, void *asn,
    X509_ALGOR *sigalg, ASN1_BIT_STRING *sig, EVP_PKEY *pkey)
{
        /* Sanity check: make sure it is PSS */
        if (OBJ_obj2nid(sigalg->algorithm) != EVP_PKEY_RSA_PSS) {
                RSAerror(RSA_R_UNSUPPORTED_SIGNATURE_TYPE);
                return -1;
        }
        if (rsa_pss_to_ctx(ctx, NULL, sigalg, pkey) > 0) {
                /* Carry on */
                return 2;
        }
        return -1;
}

static int
rsa_alg_set_pkcs1_padding(X509_ALGOR *alg)
{
        return X509_ALGOR_set0_by_nid(alg, NID_rsaEncryption, V_ASN1_NULL, NULL);
}

static int
rsa_alg_set_pss_padding(X509_ALGOR *alg, EVP_PKEY_CTX *pkey_ctx)
{
        RSA_PSS_PARAMS *pss = NULL;
        ASN1_STRING *astr = NULL;
        int ret = 0;

        if (pkey_ctx == NULL)
                goto err;

        if ((pss = rsa_ctx_to_pss(pkey_ctx)) == NULL)
                goto err;
        if ((astr = ASN1_item_pack(pss, &RSA_PSS_PARAMS_it, NULL)) == NULL)
                goto err;
        if (!X509_ALGOR_set0_by_nid(alg, EVP_PKEY_RSA_PSS, V_ASN1_SEQUENCE, astr))
                goto err;
        astr = NULL;

        ret = 1;

 err:
        ASN1_STRING_free(astr);
        RSA_PSS_PARAMS_free(pss);

        return ret;
}

#ifndef OPENSSL_NO_CMS
static int
rsa_alg_set_oaep_padding(X509_ALGOR *alg, EVP_PKEY_CTX *pkey_ctx)
{
        const EVP_MD *md, *mgf1md;
        RSA_OAEP_PARAMS *oaep = NULL;
        ASN1_STRING *astr = NULL;
        ASN1_OCTET_STRING *ostr = NULL;
        unsigned char *label;
        int label_len;
        int ret = 0;

        if (EVP_PKEY_CTX_get_rsa_oaep_md(pkey_ctx, &md) <= 0)
                goto err;
        if (EVP_PKEY_CTX_get_rsa_mgf1_md(pkey_ctx, &mgf1md) <= 0)
                goto err;
        label_len = EVP_PKEY_CTX_get0_rsa_oaep_label(pkey_ctx, &label);
        if (label_len < 0)
                goto err;

        if ((oaep = RSA_OAEP_PARAMS_new()) == NULL)
                goto err;

        if (!rsa_md_to_algor(md, &oaep->hashFunc))
                goto err;
        if (!rsa_mgf1md_to_maskGenAlgorithm(mgf1md, &oaep->maskGenFunc))
                goto err;

        /* XXX - why do we not set oaep->maskHash here? */

        if (label_len > 0) {
                if ((oaep->pSourceFunc = X509_ALGOR_new()) == NULL)
                        goto err;
                if ((ostr = ASN1_OCTET_STRING_new()) == NULL)
                        goto err;
                if (!ASN1_OCTET_STRING_set(ostr, label, label_len))
                        goto err;
                if (!X509_ALGOR_set0_by_nid(oaep->pSourceFunc, NID_pSpecified,
                    V_ASN1_OCTET_STRING, ostr))
                        goto err;
                ostr = NULL;
        }

        if ((astr = ASN1_item_pack(oaep, &RSA_OAEP_PARAMS_it, NULL)) == NULL)
                goto err;
        if (!X509_ALGOR_set0_by_nid(alg, NID_rsaesOaep, V_ASN1_SEQUENCE, astr))
                goto err;
        astr = NULL;

        ret = 1;

 err:
        RSA_OAEP_PARAMS_free(oaep);
        ASN1_STRING_free(astr);
        ASN1_OCTET_STRING_free(ostr);

        return ret;
}

static int
rsa_cms_sign(CMS_SignerInfo *si)
{
        EVP_PKEY_CTX *pkey_ctx;
        X509_ALGOR *alg;
        int pad_mode = RSA_PKCS1_PADDING;

        if ((pkey_ctx = CMS_SignerInfo_get0_pkey_ctx(si)) != NULL) {
                if (EVP_PKEY_CTX_get_rsa_padding(pkey_ctx, &pad_mode) <= 0)
                        return 0;
        }

        CMS_SignerInfo_get0_algs(si, NULL, NULL, NULL, &alg);
        if (pad_mode == RSA_PKCS1_PADDING)
                return rsa_alg_set_pkcs1_padding(alg);
        if (pad_mode == RSA_PKCS1_PSS_PADDING)
                return rsa_alg_set_pss_padding(alg, pkey_ctx);

        return 0;
}
#endif

static int
rsa_item_sign(EVP_MD_CTX *ctx, const ASN1_ITEM *it, void *asn,
    X509_ALGOR *alg1, X509_ALGOR *alg2, ASN1_BIT_STRING *sig)
{
        EVP_PKEY_CTX *pkey_ctx = ctx->pctx;
        int pad_mode;

        if (EVP_PKEY_CTX_get_rsa_padding(pkey_ctx, &pad_mode) <= 0)
                return 0;
        if (pad_mode == RSA_PKCS1_PADDING)
                return 2;
        if (pad_mode == RSA_PKCS1_PSS_PADDING) {
                if (!rsa_alg_set_pss_padding(alg1, pkey_ctx))
                        return 0;
                if (alg2 != NULL) {
                        if (!rsa_alg_set_pss_padding(alg2, pkey_ctx))
                                return 0;
                }
                return 3;
        }
        return 2;
}

#ifndef OPENSSL_NO_CMS
static RSA_OAEP_PARAMS *
rsa_oaep_decode(const X509_ALGOR *alg)
{
        RSA_OAEP_PARAMS *oaep;

        oaep = ASN1_TYPE_unpack_sequence(&RSA_OAEP_PARAMS_it, alg->parameter);
        if (oaep == NULL)
                return NULL;

        if (oaep->maskGenFunc != NULL) {
                oaep->maskHash = rsa_mgf1_decode(oaep->maskGenFunc);
                if (oaep->maskHash == NULL) {
                        RSA_OAEP_PARAMS_free(oaep);
                        return NULL;
                }
        }
        return oaep;
}

static int
rsa_cms_decrypt(CMS_RecipientInfo *ri)
{
        EVP_PKEY_CTX *pkctx;
        X509_ALGOR *cmsalg;
        int nid;
        int rv = -1;
        unsigned char *label = NULL;
        int label_len = 0;
        const EVP_MD *mgf1md = NULL, *md = NULL;
        RSA_OAEP_PARAMS *oaep;

        pkctx = CMS_RecipientInfo_get0_pkey_ctx(ri);
        if (pkctx == NULL)
                return 0;
        if (!CMS_RecipientInfo_ktri_get0_algs(ri, NULL, NULL, &cmsalg))
                return -1;
        nid = OBJ_obj2nid(cmsalg->algorithm);
        if (nid == NID_rsaEncryption)
                return 1;
        if (nid != NID_rsaesOaep) {
                RSAerror(RSA_R_UNSUPPORTED_ENCRYPTION_TYPE);
                return -1;
        }
        /* Decode OAEP parameters */
        oaep = rsa_oaep_decode(cmsalg);

        if (oaep == NULL) {
                RSAerror(RSA_R_INVALID_OAEP_PARAMETERS);
                goto err;
        }

        mgf1md = rsa_algor_to_md(oaep->maskHash);
        if (mgf1md == NULL)
                goto err;
        md = rsa_algor_to_md(oaep->hashFunc);
        if (md == NULL)
                goto err;

        if (oaep->pSourceFunc != NULL) {
                const ASN1_OBJECT *aobj;
                const void *parameter;
                int parameter_type;

                X509_ALGOR_get0(&aobj, &parameter_type, &parameter,
                    oaep->pSourceFunc);
                if (OBJ_obj2nid(aobj) != NID_pSpecified) {
                        RSAerror(RSA_R_UNSUPPORTED_LABEL_SOURCE);
                        goto err;
                }
                if (parameter_type != V_ASN1_OCTET_STRING) {
                        RSAerror(RSA_R_INVALID_LABEL);
                        goto err;
                }

                if ((label_len = ASN1_STRING_length(parameter)) == 0) {
                        RSAerror(RSA_R_INVALID_LABEL);
                        goto err;
                }

                if ((label = calloc(1, label_len)) == NULL)
                        goto err;
                memcpy(label, ASN1_STRING_get0_data(parameter), label_len);
        }

        if (EVP_PKEY_CTX_set_rsa_padding(pkctx, RSA_PKCS1_OAEP_PADDING) <= 0)
                goto err;
        if (EVP_PKEY_CTX_set_rsa_oaep_md(pkctx, md) <= 0)
                goto err;
        if (EVP_PKEY_CTX_set_rsa_mgf1_md(pkctx, mgf1md) <= 0)
                goto err;
        if (EVP_PKEY_CTX_set0_rsa_oaep_label(pkctx, label, label_len) <= 0)
                goto err;
        label = NULL;
        label_len = 0;

        rv = 1;

 err:
        RSA_OAEP_PARAMS_free(oaep);
        freezero(label, label_len);

        return rv;
}

static int
rsa_cms_encrypt(CMS_RecipientInfo *ri)
{
        X509_ALGOR *alg;
        EVP_PKEY_CTX *pkey_ctx;
        int pad_mode = RSA_PKCS1_PADDING;

        if ((pkey_ctx = CMS_RecipientInfo_get0_pkey_ctx(ri)) != NULL) {
                if (EVP_PKEY_CTX_get_rsa_padding(pkey_ctx, &pad_mode) <= 0)
                        return 0;
        }

        if (!CMS_RecipientInfo_ktri_get0_algs(ri, NULL, NULL, &alg))
                return 0;
        if (pad_mode == RSA_PKCS1_PADDING)
                return rsa_alg_set_pkcs1_padding(alg);
        if (pad_mode == RSA_PKCS1_OAEP_PADDING)
                return rsa_alg_set_oaep_padding(alg, pkey_ctx);

        return 0;
}
#endif

const EVP_PKEY_ASN1_METHOD rsa_asn1_meth = {
        .base_method = &rsa_asn1_meth,
        .pkey_id = EVP_PKEY_RSA,
        .pkey_flags = ASN1_PKEY_SIGPARAM_NULL,

        .pem_str = "RSA",
        .info = "OpenSSL RSA method",

        .pub_decode = rsa_pub_decode,
        .pub_encode = rsa_pub_encode,
        .pub_cmp = rsa_pub_cmp,
        .pub_print = rsa_pub_print,

        .priv_decode = rsa_priv_decode,
        .priv_encode = rsa_priv_encode,
        .priv_print = rsa_priv_print,

        .pkey_size = rsa_size,
        .pkey_bits = rsa_bits,
        .pkey_security_bits = rsa_security_bits,

        .sig_print = rsa_sig_print,

        .pkey_free = rsa_free,
        .pkey_ctrl = rsa_pkey_ctrl,
        .old_priv_decode = old_rsa_priv_decode,
        .old_priv_encode = old_rsa_priv_encode,
        .item_verify = rsa_item_verify,
        .item_sign = rsa_item_sign,
};

const EVP_PKEY_ASN1_METHOD rsa2_asn1_meth = {
        .base_method = &rsa_asn1_meth,
        .pkey_id = EVP_PKEY_RSA2,
        .pkey_flags = ASN1_PKEY_ALIAS,
};

const EVP_PKEY_ASN1_METHOD rsa_pss_asn1_meth = {
        .base_method = &rsa_pss_asn1_meth,
        .pkey_id = EVP_PKEY_RSA_PSS,
        .pkey_flags = ASN1_PKEY_SIGPARAM_NULL,

        .pem_str = "RSA-PSS",
        .info = "OpenSSL RSA-PSS method",

        .pub_decode = rsa_pub_decode,
        .pub_encode = rsa_pub_encode,
        .pub_cmp = rsa_pub_cmp,
        .pub_print = rsa_pub_print,

        .priv_decode = rsa_priv_decode,
        .priv_encode = rsa_priv_encode,
        .priv_print = rsa_priv_print,

        .pkey_size = rsa_size,
        .pkey_bits = rsa_bits,
        .pkey_security_bits = rsa_security_bits,

        .signature_info = rsa_pss_signature_info,

        .sig_print = rsa_sig_print,

        .pkey_free = rsa_free,
        .pkey_ctrl = rsa_pkey_ctrl,
        .item_verify = rsa_item_verify,
        .item_sign = rsa_item_sign
};