/* $OpenBSD: rsa_pmeth.c,v 1.46 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 <limits.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include <openssl/opensslconf.h>

#include <openssl/asn1t.h>
#include <openssl/bn.h>
#include <openssl/evp.h>
#include <openssl/rsa.h>
#include <openssl/x509.h>
#include <openssl/x509v3.h>

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

/* RSA pkey context structure */

typedef struct {
        /* Key gen parameters */
        int nbits;
        BIGNUM *pub_exp;
        /* Keygen callback info */
        int gentmp[2];
        /* RSA padding mode */
        int pad_mode;
        /* message digest */
        const EVP_MD *md;
        /* message digest for MGF1 */
        const EVP_MD *mgf1md;
        /* PSS salt length */
        int saltlen;
        /* Minimum salt length or -1 if no PSS parameter restriction */
        int min_saltlen;
        /* Temp buffer */
        unsigned char *tbuf;
        /* OAEP label */
        unsigned char *oaep_label;
        size_t oaep_label_len;
} RSA_PKEY_CTX;

/* True if PSS parameters are restricted */
#define rsa_pss_restricted(rctx) (rctx->min_saltlen != -1)

static int
pkey_rsa_init(EVP_PKEY_CTX *ctx)
{
        RSA_PKEY_CTX *rctx;

        if ((rctx = calloc(1, sizeof(RSA_PKEY_CTX))) == NULL)
                return 0;

        rctx->nbits = 2048;

        if (ctx->pmeth->pkey_id == EVP_PKEY_RSA_PSS)
                rctx->pad_mode = RSA_PKCS1_PSS_PADDING;
        else
                rctx->pad_mode = RSA_PKCS1_PADDING;

        /* Maximum for sign, auto for verify */
        rctx->saltlen = RSA_PSS_SALTLEN_AUTO;
        rctx->min_saltlen = -1;

        ctx->data = rctx;
        ctx->keygen_info = rctx->gentmp;
        ctx->keygen_info_count = 2;

        return 1;
}

static int
pkey_rsa_copy(EVP_PKEY_CTX *dst, EVP_PKEY_CTX *src)
{
        RSA_PKEY_CTX *dctx, *sctx;

        if (!pkey_rsa_init(dst))
                return 0;

        sctx = src->data;
        dctx = dst->data;
        dctx->nbits = sctx->nbits;
        if (sctx->pub_exp != NULL) {
                BN_free(dctx->pub_exp);
                if ((dctx->pub_exp = BN_dup(sctx->pub_exp)) == NULL)
                        return 0;
        }
        dctx->pad_mode = sctx->pad_mode;
        dctx->md = sctx->md;
        dctx->mgf1md = sctx->mgf1md;
        if (sctx->oaep_label != NULL) {
                free(dctx->oaep_label);
                if ((dctx->oaep_label = calloc(1, sctx->oaep_label_len)) == NULL)
                        return 0;
                memcpy(dctx->oaep_label, sctx->oaep_label, sctx->oaep_label_len);
                dctx->oaep_label_len = sctx->oaep_label_len;
        }

        return 1;
}

static int
setup_tbuf(RSA_PKEY_CTX *ctx, EVP_PKEY_CTX *pk)
{
        if (ctx->tbuf != NULL)
                return 1;
        if ((ctx->tbuf = calloc(1, EVP_PKEY_size(pk->pkey))) == NULL) {
                RSAerror(ERR_R_MALLOC_FAILURE);
                return 0;
        }
        return 1;
}

static void
pkey_rsa_cleanup(EVP_PKEY_CTX *ctx)
{
        RSA_PKEY_CTX *rctx = ctx->data;

        if (rctx) {
                BN_free(rctx->pub_exp);
                free(rctx->tbuf);
                free(rctx->oaep_label);
                free(rctx);
        }
}

static int
pkey_rsa_sign(EVP_PKEY_CTX *ctx, unsigned char *sig, size_t *siglen,
    const unsigned char *tbs, size_t tbslen)
{
        int ret;
        RSA_PKEY_CTX *rctx = ctx->data;
        RSA *rsa = ctx->pkey->pkey.rsa;

        if (rctx->md) {
                if (tbslen != (size_t)EVP_MD_size(rctx->md)) {
                        RSAerror(RSA_R_INVALID_DIGEST_LENGTH);
                        return -1;
                }

                if (rctx->pad_mode == RSA_X931_PADDING) {
                        if ((size_t)EVP_PKEY_size(ctx->pkey) < tbslen + 1) {
                                RSAerror(RSA_R_KEY_SIZE_TOO_SMALL);
                                return -1;
                        }
                        if (!setup_tbuf(rctx, ctx)) {
                                RSAerror(ERR_R_MALLOC_FAILURE);
                                return -1;
                        }
                        memcpy(rctx->tbuf, tbs, tbslen);
                        rctx->tbuf[tbslen] =
                            RSA_X931_hash_id(EVP_MD_type(rctx->md));
                        ret = RSA_private_encrypt(tbslen + 1, rctx->tbuf, sig,
                            rsa, RSA_X931_PADDING);
                } else if (rctx->pad_mode == RSA_PKCS1_PADDING) {
                        unsigned int sltmp;

                        ret = RSA_sign(EVP_MD_type(rctx->md), tbs, tbslen, sig,
                            &sltmp, rsa);
                        if (ret <= 0)
                                return ret;
                        ret = sltmp;
                } else if (rctx->pad_mode == RSA_PKCS1_PSS_PADDING) {
                        if (!setup_tbuf(rctx, ctx))
                                return -1;
                        if (!RSA_padding_add_PKCS1_PSS_mgf1(rsa, rctx->tbuf,
                            tbs, rctx->md, rctx->mgf1md, rctx->saltlen))
                                return -1;
                        ret = RSA_private_encrypt(RSA_size(rsa), rctx->tbuf,
                            sig, rsa, RSA_NO_PADDING);
                } else {
                        return -1;
                }
        } else {
                ret = RSA_private_encrypt(tbslen, tbs, sig, ctx->pkey->pkey.rsa,
                    rctx->pad_mode);
        }
        if (ret < 0)
                return ret;
        *siglen = ret;
        return 1;
}

static int
pkey_rsa_verifyrecover(EVP_PKEY_CTX *ctx, unsigned char *rout, size_t *routlen,
    const unsigned char *sig, size_t siglen)
{
        int ret;
        RSA_PKEY_CTX *rctx = ctx->data;

        if (rctx->md) {
                if (rctx->pad_mode == RSA_X931_PADDING) {
                        if (!setup_tbuf(rctx, ctx))
                                return -1;
                        ret = RSA_public_decrypt(siglen, sig, rctx->tbuf,
                            ctx->pkey->pkey.rsa, RSA_X931_PADDING);
                        if (ret < 1)
                                return 0;
                        ret--;
                        if (rctx->tbuf[ret] !=
                            RSA_X931_hash_id(EVP_MD_type(rctx->md))) {
                                RSAerror(RSA_R_ALGORITHM_MISMATCH);
                                return 0;
                        }
                        if (ret != EVP_MD_size(rctx->md)) {
                                RSAerror(RSA_R_INVALID_DIGEST_LENGTH);
                                return 0;
                        }
                        if (rout)
                                memcpy(rout, rctx->tbuf, ret);
                } else if (rctx->pad_mode == RSA_PKCS1_PADDING) {
                        size_t sltmp;

                        ret = int_rsa_verify(EVP_MD_type(rctx->md), NULL, 0,
                            rout, &sltmp, sig, siglen, ctx->pkey->pkey.rsa);
                        if (ret <= 0)
                                return 0;
                        ret = sltmp;
                } else {
                        return -1;
                }
        } else {
                ret = RSA_public_decrypt(siglen, sig, rout, ctx->pkey->pkey.rsa,
                    rctx->pad_mode);
        }
        if (ret < 0)
                return ret;
        *routlen = ret;
        return 1;
}

static int
pkey_rsa_verify(EVP_PKEY_CTX *ctx, const unsigned char *sig, size_t siglen,
    const unsigned char *tbs, size_t tbslen)
{
        RSA_PKEY_CTX *rctx = ctx->data;
        RSA *rsa = ctx->pkey->pkey.rsa;
        size_t rslen;

        if (rctx->md) {
                if (rctx->pad_mode == RSA_PKCS1_PADDING)
                        return RSA_verify(EVP_MD_type(rctx->md), tbs, tbslen,
                            sig, siglen, rsa);
                if (tbslen != (size_t)EVP_MD_size(rctx->md)) {
                        RSAerror(RSA_R_INVALID_DIGEST_LENGTH);
                        return -1;
                }
                if (rctx->pad_mode == RSA_X931_PADDING) {
                        if (pkey_rsa_verifyrecover(ctx, NULL, &rslen, sig,
                            siglen) <= 0)
                                return 0;
                } else if (rctx->pad_mode == RSA_PKCS1_PSS_PADDING) {
                        int ret;

                        if (!setup_tbuf(rctx, ctx))
                                return -1;
                        ret = RSA_public_decrypt(siglen, sig, rctx->tbuf,
                            rsa, RSA_NO_PADDING);
                        if (ret <= 0)
                                return 0;
                        ret = RSA_verify_PKCS1_PSS_mgf1(rsa, tbs, rctx->md,
                            rctx->mgf1md, rctx->tbuf, rctx->saltlen);
                        if (ret <= 0)
                                return 0;
                        return 1;
                } else {
                        return -1;
                }
        } else {
                int ret;

                if (!setup_tbuf(rctx, ctx))
                        return -1;

                if ((ret = RSA_public_decrypt(siglen, sig, rctx->tbuf, rsa,
                    rctx->pad_mode)) <= 0)
                        return 0;

                rslen = ret;
        }

        if (rslen != tbslen || timingsafe_bcmp(tbs, rctx->tbuf, rslen))
                return 0;

        return 1;
}

static int
pkey_rsa_encrypt(EVP_PKEY_CTX *ctx, unsigned char *out, size_t *outlen,
    const unsigned char *in, size_t inlen)
{
        RSA_PKEY_CTX *rctx = ctx->data;
        int ret;

        if (rctx->pad_mode == RSA_PKCS1_OAEP_PADDING) {
                int klen = RSA_size(ctx->pkey->pkey.rsa);
                if (!setup_tbuf(rctx, ctx))
                        return -1;
                if (!RSA_padding_add_PKCS1_OAEP_mgf1(rctx->tbuf, klen,
                    in, inlen, rctx->oaep_label, rctx->oaep_label_len,
                    rctx->md, rctx->mgf1md))
                        return -1;
                ret = RSA_public_encrypt(klen, rctx->tbuf, out,
                    ctx->pkey->pkey.rsa, RSA_NO_PADDING);
        } else {
                ret = RSA_public_encrypt(inlen, in, out, ctx->pkey->pkey.rsa,
                    rctx->pad_mode);
        }
        if (ret < 0)
                return ret;
        *outlen = ret;
        return 1;
}

static int
pkey_rsa_decrypt(EVP_PKEY_CTX *ctx, unsigned char *out, size_t *outlen,
    const unsigned char *in, size_t inlen)
{
        int ret;
        RSA_PKEY_CTX *rctx = ctx->data;

        if (rctx->pad_mode == RSA_PKCS1_OAEP_PADDING) {
                if (!setup_tbuf(rctx, ctx))
                        return -1;
                ret = RSA_private_decrypt(inlen, in, rctx->tbuf,
                    ctx->pkey->pkey.rsa, RSA_NO_PADDING);
                if (ret <= 0)
                        return ret;
                ret = RSA_padding_check_PKCS1_OAEP_mgf1(out, ret, rctx->tbuf,
                    ret, ret, rctx->oaep_label, rctx->oaep_label_len, rctx->md,
                    rctx->mgf1md);
        } else {
                ret = RSA_private_decrypt(inlen, in, out, ctx->pkey->pkey.rsa,
                    rctx->pad_mode);
        }
        if (ret < 0)
                return ret;
        *outlen = ret;
        return 1;
}

static int
check_padding_md(const EVP_MD *md, int padding)
{
        if (md == NULL)
                return 1;

        if (padding == RSA_NO_PADDING) {
                RSAerror(RSA_R_INVALID_PADDING_MODE);
                return 0;
        }

        if (padding == RSA_X931_PADDING) {
                if (RSA_X931_hash_id(EVP_MD_type(md)) == -1) {
                        RSAerror(RSA_R_INVALID_X931_DIGEST);
                        return 0;
                }
        } else {
                /* List of all supported RSA digests. */
                /* RFC 8017 and NIST CSOR. */
                switch(EVP_MD_type(md)) {
                case NID_sha1:
                case NID_sha224:
                case NID_sha256:
                case NID_sha384:
                case NID_sha512:
                case NID_sha512_224:
                case NID_sha512_256:
                case NID_sha3_224:
                case NID_sha3_256:
                case NID_sha3_384:
                case NID_sha3_512:
                case NID_md5:
                case NID_md5_sha1:
                case NID_md4:
                case NID_ripemd160:
                        return 1;

                default:
                        RSAerror(RSA_R_INVALID_DIGEST);
                        return 0;
                }
        }

        return 1;
}

static int
pkey_rsa_ctrl(EVP_PKEY_CTX *ctx, int type, int p1, void *p2)
{
        RSA_PKEY_CTX *rctx = ctx->data;

        switch (type) {
        case EVP_PKEY_CTRL_RSA_PADDING:
                if (p1 >= RSA_PKCS1_PADDING && p1 <= RSA_PKCS1_PSS_PADDING) {
                        if (!check_padding_md(rctx->md, p1))
                                return 0;
                        if (p1 == RSA_PKCS1_PSS_PADDING) {
                                if (!(ctx->operation &
                                    (EVP_PKEY_OP_SIGN | EVP_PKEY_OP_VERIFY)))
                                        goto bad_pad;
                                if (!rctx->md)
                                        rctx->md = EVP_sha1();
                        } else if (ctx->pmeth->pkey_id == EVP_PKEY_RSA_PSS) {
                                goto bad_pad;
                        }
                        if (p1 == RSA_PKCS1_OAEP_PADDING) {
                                if (!(ctx->operation & EVP_PKEY_OP_TYPE_CRYPT))
                                        goto bad_pad;
                                if (!rctx->md)
                                        rctx->md = EVP_sha1();
                        }
                        rctx->pad_mode = p1;
                        return 1;
                }
 bad_pad:
                RSAerror(RSA_R_ILLEGAL_OR_UNSUPPORTED_PADDING_MODE);
                return -2;

        case EVP_PKEY_CTRL_GET_RSA_PADDING:
                *(int *)p2 = rctx->pad_mode;
                return 1;

        case EVP_PKEY_CTRL_RSA_PSS_SALTLEN:
        case EVP_PKEY_CTRL_GET_RSA_PSS_SALTLEN:
                if (rctx->pad_mode != RSA_PKCS1_PSS_PADDING) {
                        RSAerror(RSA_R_INVALID_PSS_SALTLEN);
                        return -2;
                }
                if (type == EVP_PKEY_CTRL_GET_RSA_PSS_SALTLEN) {
                        *(int *)p2 = rctx->saltlen;
                } else {
                        if (p1 < RSA_PSS_SALTLEN_MAX)
                                return -2;
                        if (rsa_pss_restricted(rctx)) {
                                if (p1 == RSA_PSS_SALTLEN_AUTO &&
                                    ctx->operation == EVP_PKEY_OP_VERIFY) {
                                        RSAerror(RSA_R_INVALID_PSS_SALTLEN);
                                        return -2;
                                }
                                if ((p1 == RSA_PSS_SALTLEN_DIGEST &&
                                    rctx->min_saltlen > EVP_MD_size(rctx->md)) ||
                                    (p1 >= 0 && p1 < rctx->min_saltlen)) {
                                        RSAerror(RSA_R_PSS_SALTLEN_TOO_SMALL);
                                        return 0;
                                }
                        }
                        rctx->saltlen = p1;
                }
                return 1;

        case EVP_PKEY_CTRL_RSA_KEYGEN_BITS:
                if (p1 < RSA_MIN_MODULUS_BITS) {
                        RSAerror(RSA_R_KEY_SIZE_TOO_SMALL);
                        return -2;
                }
                rctx->nbits = p1;
                return 1;

        case EVP_PKEY_CTRL_RSA_KEYGEN_PUBEXP:
                if (p2 == NULL || !BN_is_odd((BIGNUM *)p2) ||
                    BN_is_one((BIGNUM *)p2)) {
                        RSAerror(RSA_R_BAD_E_VALUE);
                        return -2;
                }
                BN_free(rctx->pub_exp);
                rctx->pub_exp = p2;
                return 1;

        case EVP_PKEY_CTRL_RSA_OAEP_MD:
        case EVP_PKEY_CTRL_GET_RSA_OAEP_MD:
                if (rctx->pad_mode != RSA_PKCS1_OAEP_PADDING) {
                        RSAerror(RSA_R_INVALID_PADDING_MODE);
                        return -2;
                }
                if (type == EVP_PKEY_CTRL_GET_RSA_OAEP_MD)
                        *(const EVP_MD **)p2 = rctx->md;
                else
                        rctx->md = p2;
                return 1;

        case EVP_PKEY_CTRL_MD:
                if (!check_padding_md(p2, rctx->pad_mode))
                        return 0;
                if (rsa_pss_restricted(rctx)) {
                        if (EVP_MD_type(rctx->md) == EVP_MD_type(p2))
                                return 1;
                        RSAerror(RSA_R_DIGEST_NOT_ALLOWED);
                        return 0;
                }
                rctx->md = p2;
                return 1;

        case EVP_PKEY_CTRL_GET_MD:
                *(const EVP_MD **)p2 = rctx->md;
                return 1;

        case EVP_PKEY_CTRL_RSA_MGF1_MD:
        case EVP_PKEY_CTRL_GET_RSA_MGF1_MD:
                if (rctx->pad_mode != RSA_PKCS1_PSS_PADDING &&
                    rctx->pad_mode != RSA_PKCS1_OAEP_PADDING) {
                        RSAerror(RSA_R_INVALID_MGF1_MD);
                        return -2;
                }
                if (type == EVP_PKEY_CTRL_GET_RSA_MGF1_MD) {
                        if (rctx->mgf1md)
                                *(const EVP_MD **)p2 = rctx->mgf1md;
                        else
                                *(const EVP_MD **)p2 = rctx->md;
                } else {
                        if (rsa_pss_restricted(rctx)) {
                                if (EVP_MD_type(rctx->mgf1md) == EVP_MD_type(p2))
                                        return 1;
                                RSAerror(RSA_R_MGF1_DIGEST_NOT_ALLOWED);
                                return 0;
                        }
                        rctx->mgf1md = p2;
                }
                return 1;

        case EVP_PKEY_CTRL_RSA_OAEP_LABEL:
                if (rctx->pad_mode != RSA_PKCS1_OAEP_PADDING) {
                        RSAerror(RSA_R_INVALID_PADDING_MODE);
                        return -2;
                }
                freezero(rctx->oaep_label, rctx->oaep_label_len);
                if (p2 != NULL && p1 > 0) {
                        rctx->oaep_label = p2;
                        rctx->oaep_label_len = p1;
                } else {
                        rctx->oaep_label = NULL;
                        rctx->oaep_label_len = 0;
                }
                return 1;

        case EVP_PKEY_CTRL_GET_RSA_OAEP_LABEL:
                if (rctx->pad_mode != RSA_PKCS1_OAEP_PADDING) {
                        RSAerror(RSA_R_INVALID_PADDING_MODE);
                        return -2;
                }
                *(unsigned char **)p2 = rctx->oaep_label;
                return rctx->oaep_label_len;

        case EVP_PKEY_CTRL_DIGESTINIT:
        case EVP_PKEY_CTRL_PKCS7_SIGN:
#ifndef OPENSSL_NO_CMS
        case EVP_PKEY_CTRL_CMS_SIGN:
#endif
                return 1;

        case EVP_PKEY_CTRL_PKCS7_ENCRYPT:
        case EVP_PKEY_CTRL_PKCS7_DECRYPT:
#ifndef OPENSSL_NO_CMS
        case EVP_PKEY_CTRL_CMS_DECRYPT:
        case EVP_PKEY_CTRL_CMS_ENCRYPT:
#endif
                if (ctx->pmeth->pkey_id != EVP_PKEY_RSA_PSS)
                        return 1;

        /* fall through */
        case EVP_PKEY_CTRL_PEER_KEY:
                RSAerror(RSA_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE);
                return -2;

        default:
                return -2;

        }
}

static int
pkey_rsa_ctrl_str(EVP_PKEY_CTX *ctx, const char *type, const char *value)
{
        const char *errstr;

        if (!value) {
                RSAerror(RSA_R_VALUE_MISSING);
                return 0;
        }
        if (strcmp(type, "rsa_padding_mode") == 0) {
                int pm;
                if (strcmp(value, "pkcs1") == 0)
                        pm = RSA_PKCS1_PADDING;
                else if (strcmp(value, "none") == 0)
                        pm = RSA_NO_PADDING;
                else if (strcmp(value, "oaep") == 0 || strcmp(value, "oeap") == 0)
                        pm = RSA_PKCS1_OAEP_PADDING;
                else if (strcmp(value, "x931") == 0)
                        pm = RSA_X931_PADDING;
                else if (strcmp(value, "pss") == 0)
                        pm = RSA_PKCS1_PSS_PADDING;
                else {
                        RSAerror(RSA_R_UNKNOWN_PADDING_TYPE);
                        return -2;
                }
                return EVP_PKEY_CTX_set_rsa_padding(ctx, pm);
        }

        if (strcmp(type, "rsa_pss_saltlen") == 0) {
                int saltlen;

                if (strcmp(value, "digest") == 0)
                        saltlen = RSA_PSS_SALTLEN_DIGEST;
                else if (strcmp(value, "max") == 0)
                        saltlen = RSA_PSS_SALTLEN_MAX;
                else if (strcmp(value, "auto") == 0)
                        saltlen = RSA_PSS_SALTLEN_AUTO;
                else {
                        /*
                         * Accept the special values -1, -2, -3 since that's
                         * what atoi() historically did. Lower values are later
                         * rejected in EVP_PKEY_CTRL_RSA_PSS_SALTLEN anyway.
                         */
                        saltlen = strtonum(value, -3, INT_MAX, &errstr);
                        if (errstr != NULL) {
                                RSAerror(RSA_R_INVALID_PSS_SALTLEN);
                                return -2;
                        }
                }
                return EVP_PKEY_CTX_set_rsa_pss_saltlen(ctx, saltlen);
        }

        if (strcmp(type, "rsa_keygen_bits") == 0) {
                int nbits;

                nbits = strtonum(value, 0, INT_MAX, &errstr);
                if (errstr != NULL) {
                        RSAerror(RSA_R_INVALID_KEYBITS);
                        return -2;
                }

                return EVP_PKEY_CTX_set_rsa_keygen_bits(ctx, nbits);
        }

        if (strcmp(type, "rsa_keygen_pubexp") == 0) {
                BIGNUM *pubexp = NULL;
                int ret;

                if (!BN_asc2bn(&pubexp, value))
                        return 0;
                ret = EVP_PKEY_CTX_set_rsa_keygen_pubexp(ctx, pubexp);
                if (ret <= 0)
                        BN_free(pubexp);
                return ret;
        }

        if (strcmp(type, "rsa_mgf1_md") == 0)
                return EVP_PKEY_CTX_md(ctx,
                    EVP_PKEY_OP_TYPE_SIG | EVP_PKEY_OP_TYPE_CRYPT,
                    EVP_PKEY_CTRL_RSA_MGF1_MD, value);

        if (ctx->pmeth->pkey_id == EVP_PKEY_RSA_PSS) {
                if (strcmp(type, "rsa_pss_keygen_mgf1_md") == 0)
                        return EVP_PKEY_CTX_md(ctx, EVP_PKEY_OP_KEYGEN,
                            EVP_PKEY_CTRL_RSA_MGF1_MD, value);

                if (strcmp(type, "rsa_pss_keygen_md") == 0)
                        return EVP_PKEY_CTX_md(ctx, EVP_PKEY_OP_KEYGEN,
                            EVP_PKEY_CTRL_MD, value);

                if (strcmp(type, "rsa_pss_keygen_saltlen") == 0) {
                        int saltlen;

                        /*
                         * Accept the special values -1, -2, -3 since that's
                         * what atoi() historically did. Lower values are later
                         * rejected in EVP_PKEY_CTRL_RSA_PSS_SALTLEN anyway.
                         */
                        saltlen = strtonum(value, -3, INT_MAX, &errstr);
                        if (errstr != NULL) {
                                RSAerror(RSA_R_INVALID_PSS_SALTLEN);
                                return -2;
                        }

                        return EVP_PKEY_CTX_set_rsa_pss_keygen_saltlen(ctx, saltlen);
                }
        }

        if (strcmp(type, "rsa_oaep_md") == 0)
                return EVP_PKEY_CTX_md(ctx, EVP_PKEY_OP_TYPE_CRYPT,
                    EVP_PKEY_CTRL_RSA_OAEP_MD, value);

        if (strcmp(type, "rsa_oaep_label") == 0) {
                unsigned char *lab;
                long lablen;
                int ret;

                if ((lab = string_to_hex(value, &lablen)) == NULL)
                        return 0;
                ret = EVP_PKEY_CTX_set0_rsa_oaep_label(ctx, lab, lablen);
                if (ret <= 0)
                        free(lab);

                return ret;
        }

        return -2;
}

/* Set PSS parameters when generating a key, if necessary. */
static int
rsa_set_pss_param(RSA *rsa, EVP_PKEY_CTX *ctx)
{
        RSA_PKEY_CTX *rctx = ctx->data;

        if (ctx->pmeth->pkey_id != EVP_PKEY_RSA_PSS)
                return 1;

        /* If all parameters are default values then do not set PSS. */
        if (rctx->md == NULL && rctx->mgf1md == NULL &&
            rctx->saltlen == RSA_PSS_SALTLEN_AUTO)
                return 1;

        rsa->pss = rsa_pss_params_create(rctx->md, rctx->mgf1md,
            rctx->saltlen == RSA_PSS_SALTLEN_AUTO ? 0 : rctx->saltlen);
        if (rsa->pss == NULL)
                return 0;

        return 1;
}

static int
pkey_rsa_keygen(EVP_PKEY_CTX *ctx, EVP_PKEY *pkey)
{
        RSA *rsa = NULL;
        RSA_PKEY_CTX *rctx = ctx->data;
        BN_GENCB *pcb = NULL;
        BN_GENCB cb = {0};
        int ret = 0;

        if (rctx->pub_exp == NULL) {
                if ((rctx->pub_exp = BN_new()) == NULL)
                        goto err;
                if (!BN_set_word(rctx->pub_exp, RSA_F4))
                        goto err;
        }

        if ((rsa = RSA_new()) == NULL)
                goto err;
        if (ctx->pkey_gencb != NULL) {
                pcb = &cb;
                evp_pkey_set_cb_translate(pcb, ctx);
        }
        if (!RSA_generate_key_ex(rsa, rctx->nbits, rctx->pub_exp, pcb))
                goto err;
        if (!rsa_set_pss_param(rsa, ctx))
                goto err;
        if (!EVP_PKEY_assign(pkey, ctx->pmeth->pkey_id, rsa))
                goto err;
        rsa = NULL;

        ret = 1;

 err:
        RSA_free(rsa);

        return ret;
}

const EVP_PKEY_METHOD rsa_pkey_meth = {
        .pkey_id = EVP_PKEY_RSA,
        .flags = EVP_PKEY_FLAG_AUTOARGLEN,

        .init = pkey_rsa_init,
        .copy = pkey_rsa_copy,
        .cleanup = pkey_rsa_cleanup,

        .keygen = pkey_rsa_keygen,

        .sign = pkey_rsa_sign,

        .verify = pkey_rsa_verify,

        .verify_recover = pkey_rsa_verifyrecover,

        .encrypt = pkey_rsa_encrypt,

        .decrypt = pkey_rsa_decrypt,

        .ctrl = pkey_rsa_ctrl,
        .ctrl_str = pkey_rsa_ctrl_str
};

/*
 * Called for PSS sign or verify initialisation: checks PSS parameter
 * sanity and sets any restrictions on key usage.
 */

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 (ctx->pmeth->pkey_id != EVP_PKEY_RSA_PSS)
                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 minimum 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) {
                RSAerror(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;
}

const EVP_PKEY_METHOD rsa_pss_pkey_meth = {
        .pkey_id = EVP_PKEY_RSA_PSS,
        .flags = EVP_PKEY_FLAG_AUTOARGLEN,

        .init = pkey_rsa_init,
        .copy = pkey_rsa_copy,
        .cleanup = pkey_rsa_cleanup,

        .keygen = pkey_rsa_keygen,

        .sign_init = pkey_pss_init,
        .sign = pkey_rsa_sign,

        .verify_init = pkey_pss_init,
        .verify = pkey_rsa_verify,

        .ctrl = pkey_rsa_ctrl,
        .ctrl_str = pkey_rsa_ctrl_str
};