/*

 * Copyright 2019-2025 The OpenSSL Project Authors. All Rights Reserved.

 *

 * Licensed under the Apache License 2.0 (the "License").  You may not use

 * this file except in compliance with the License.  You can obtain a copy

 * in the file LICENSE in the source distribution or at

 * https://www.openssl.org/source/license.html

 */

/*

 * RSA low level APIs are deprecated for public use, but still ok for

 * internal use.

 */

#include "internal/deprecated.h"

#include <openssl/crypto.h>

#include <openssl/evp.h>

#include <openssl/core_dispatch.h>

#include <openssl/core_names.h>

#include <openssl/rsa.h>

#include <openssl/params.h>

#include <openssl/err.h>

#include <openssl/proverr.h>

/* Just for SSL_MAX_MASTER_KEY_LENGTH */

#include <openssl/prov_ssl.h>

#include "internal/constant_time.h"

#include "internal/cryptlib.h"

#include "internal/fips.h"

#include "internal/sizes.h"

#include "crypto/rsa.h"

#include "prov/provider_ctx.h"

#include "prov/implementations.h"

#include "prov/providercommon.h"

#include "prov/securitycheck.h"

#include <stdlib.h>

#include "providers/implementations/asymciphers/rsa_enc.inc"

static OSSL_FUNC_asym_cipher_newctx_fn rsa_newctx;

static OSSL_FUNC_asym_cipher_encrypt_init_fn rsa_encrypt_init;

static OSSL_FUNC_asym_cipher_encrypt_fn rsa_encrypt;

static OSSL_FUNC_asym_cipher_decrypt_init_fn rsa_decrypt_init;

static OSSL_FUNC_asym_cipher_decrypt_fn rsa_decrypt;

static OSSL_FUNC_asym_cipher_freectx_fn rsa_freectx;

static OSSL_FUNC_asym_cipher_dupctx_fn rsa_dupctx;

static OSSL_FUNC_asym_cipher_get_ctx_params_fn rsa_get_ctx_params;

static OSSL_FUNC_asym_cipher_gettable_ctx_params_fn rsa_gettable_ctx_params;

static OSSL_FUNC_asym_cipher_set_ctx_params_fn rsa_set_ctx_params;

static OSSL_FUNC_asym_cipher_settable_ctx_params_fn rsa_settable_ctx_params;

static OSSL_ITEM padding_item[] = {

    { RSA_PKCS1_PADDING, OSSL_PKEY_RSA_PAD_MODE_PKCSV15 },

    { RSA_NO_PADDING, OSSL_PKEY_RSA_PAD_MODE_NONE },

    { RSA_PKCS1_OAEP_PADDING, OSSL_PKEY_RSA_PAD_MODE_OAEP }, /* Correct spelling first */

    { RSA_PKCS1_OAEP_PADDING, "oeap" },

    { 0, NULL }

};

/*

 * What's passed as an actual key is defined by the KEYMGMT interface.

 * We happen to know that our KEYMGMT simply passes RSA structures, so

 * we use that here too.

 */

typedef struct {

    OSSL_LIB_CTX *libctx;

    RSA *rsa;

    int pad_mode;

    int operation;

    /* OAEP message digest */

    EVP_MD *oaep_md;

    /* message digest for MGF1 */

    EVP_MD *mgf1_md;

    /* OAEP label */

    unsigned char *oaep_label;

    size_t oaep_labellen;

    /* TLS padding */

    unsigned int client_version;

    unsigned int alt_version;

    /* PKCS#1 v1.5 decryption mode */

    unsigned int implicit_rejection;

    OSSL_FIPS_IND_DECLARE

} PROV_RSA_CTX;

static void *rsa_newctx(void *provctx)

{

    PROV_RSA_CTX *prsactx;

    if (!ossl_prov_is_running())

        return NULL;

#ifdef FIPS_MODULE

    if (!ossl_deferred_self_test(PROV_LIBCTX_OF(provctx),

            ST_ID_ASYM_CIPHER_RSA_ENC))

        return NULL;

#endif

    prsactx = OPENSSL_zalloc(sizeof(PROV_RSA_CTX));

    if (prsactx == NULL)

        return NULL;

    prsactx->libctx = PROV_LIBCTX_OF(provctx);

    OSSL_FIPS_IND_INIT(prsactx)

    return prsactx;

}

static int rsa_init(void *vprsactx, void *vrsa, const OSSL_PARAM params[],

    int operation, const char *desc)

{

    PROV_RSA_CTX *prsactx = (PROV_RSA_CTX *)vprsactx;

    int protect = 0;

    if (!ossl_prov_is_running() || prsactx == NULL || vrsa == NULL)

        return 0;

    if (!ossl_rsa_key_op_get_protect(vrsa, operation, &protect))

        return 0;

    if (!RSA_up_ref(vrsa))

        return 0;

    RSA_free(prsactx->rsa);

    prsactx->rsa = vrsa;

    prsactx->operation = operation;

    prsactx->implicit_rejection = 1;

    switch (RSA_test_flags(prsactx->rsa, RSA_FLAG_TYPE_MASK)) {

    case RSA_FLAG_TYPE_RSA:

        prsactx->pad_mode = RSA_PKCS1_PADDING;

        break;

    default:

        /* This should not happen due to the check above */

        ERR_raise(ERR_LIB_PROV, ERR_R_INTERNAL_ERROR);

        return 0;

    }

    OSSL_FIPS_IND_SET_APPROVED(prsactx)

    if (!rsa_set_ctx_params(prsactx, params))

        return 0;

#ifdef FIPS_MODULE

    if (!ossl_fips_ind_rsa_key_check(OSSL_FIPS_IND_GET(prsactx),

            OSSL_FIPS_IND_SETTABLE0, prsactx->libctx,

            prsactx->rsa, desc, protect))

        return 0;

#endif

    return 1;

}

static int rsa_encrypt_init(void *vprsactx, void *vrsa,

    const OSSL_PARAM params[])

{

    return rsa_init(vprsactx, vrsa, params, EVP_PKEY_OP_ENCRYPT,

        "RSA Encrypt Init");

}

static int rsa_decrypt_init(void *vprsactx, void *vrsa,

    const OSSL_PARAM params[])

{

    return rsa_init(vprsactx, vrsa, params, EVP_PKEY_OP_DECRYPT,

        "RSA Decrypt Init");

}

static int rsa_encrypt(void *vprsactx, unsigned char *out, size_t *outlen,

    size_t outsize, const unsigned char *in, size_t inlen)

{

    PROV_RSA_CTX *prsactx = (PROV_RSA_CTX *)vprsactx;

    size_t len = RSA_size(prsactx->rsa);

    int ret;

    if (!ossl_prov_is_running())

        return 0;

#ifdef FIPS_MODULE

    if ((prsactx->pad_mode == RSA_PKCS1_PADDING

            || prsactx->pad_mode == RSA_PKCS1_WITH_TLS_PADDING)

        && !OSSL_FIPS_IND_ON_UNAPPROVED(prsactx, OSSL_FIPS_IND_SETTABLE1,

            prsactx->libctx, "RSA Encrypt",

            "PKCS#1 v1.5 padding",

            ossl_fips_config_rsa_pkcs15_padding_disabled)) {

        ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_PADDING_MODE);

        return 0;

    }

#endif

    if (len == 0) {

        ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_KEY);

        return 0;

    }

    if (out == NULL) {

        *outlen = len;

        return 1;

    }

    if (outsize < len) {

        ERR_raise(ERR_LIB_PROV, PROV_R_OUTPUT_BUFFER_TOO_SMALL);

        return 0;

    }

    if (prsactx->pad_mode == RSA_PKCS1_OAEP_PADDING) {

        int rsasize = RSA_size(prsactx->rsa);

        unsigned char *tbuf;

        if ((tbuf = OPENSSL_malloc(rsasize)) == NULL)

            return 0;

        if (prsactx->oaep_md == NULL) {

            prsactx->oaep_md = EVP_MD_fetch(prsactx->libctx, "SHA-1", NULL);

            if (prsactx->oaep_md == NULL) {

                OPENSSL_free(tbuf);

                ERR_raise(ERR_LIB_PROV, ERR_R_INTERNAL_ERROR);

                return 0;

            }

        }

        ret = ossl_rsa_padding_add_PKCS1_OAEP_mgf1_ex(prsactx->libctx, tbuf,

            rsasize, in, (int)inlen,

            prsactx->oaep_label,

            (int)prsactx->oaep_labellen,

            prsactx->oaep_md,

            prsactx->mgf1_md);

        if (!ret) {

            OPENSSL_free(tbuf);

            return 0;

        }

        ret = RSA_public_encrypt(rsasize, tbuf, out, prsactx->rsa,

            RSA_NO_PADDING);

        OPENSSL_free(tbuf);

    } else {

        ret = RSA_public_encrypt((int)inlen, in, out, prsactx->rsa,

            prsactx->pad_mode);

    }

    /* A ret value of 0 is not an error */

    if (ret < 0)

        return ret;

    *outlen = ret;

    return 1;

}

static int rsa_decrypt(void *vprsactx, unsigned char *out, size_t *outlen,

    size_t outsize, const unsigned char *in, size_t inlen)

{

    PROV_RSA_CTX *prsactx = (PROV_RSA_CTX *)vprsactx;

    int ret;

    int pad_mode;

    size_t len = RSA_size(prsactx->rsa);

    if (!ossl_prov_is_running())

        return 0;

    if (prsactx->pad_mode == RSA_PKCS1_WITH_TLS_PADDING) {

        if (out == NULL) {

            *outlen = SSL_MAX_MASTER_KEY_LENGTH;

            return 1;

        }

        if (outsize < SSL_MAX_MASTER_KEY_LENGTH) {

            ERR_raise(ERR_LIB_PROV, PROV_R_BAD_LENGTH);

            return 0;

        }

    } else {

        if (out == NULL) {

            if (len == 0) {

                ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_KEY);

                return 0;

            }

            *outlen = len;

            return 1;

        }

        if (outsize < len) {

            ERR_raise(ERR_LIB_PROV, PROV_R_BAD_LENGTH);

            return 0;

        }

    }

    if (prsactx->pad_mode == RSA_PKCS1_OAEP_PADDING

        || prsactx->pad_mode == RSA_PKCS1_WITH_TLS_PADDING) {

        unsigned char *tbuf;

        if ((tbuf = OPENSSL_malloc(len)) == NULL)

            return 0;

        ret = RSA_private_decrypt((int)inlen, in, tbuf, prsactx->rsa,

            RSA_NO_PADDING);

        /*

         * With no padding then, on success ret should be len, otherwise an

         * error occurred (non-constant time)

         */

        if (ret != (int)len) {

            OPENSSL_free(tbuf);

            ERR_raise(ERR_LIB_PROV, PROV_R_FAILED_TO_DECRYPT);

            return 0;

        }

        if (prsactx->pad_mode == RSA_PKCS1_OAEP_PADDING) {

            if (prsactx->oaep_md == NULL) {

                prsactx->oaep_md = EVP_MD_fetch(prsactx->libctx, "SHA-1", NULL);

                if (prsactx->oaep_md == NULL) {

                    OPENSSL_free(tbuf);

                    ERR_raise(ERR_LIB_PROV, ERR_R_INTERNAL_ERROR);

                    return 0;

                }

            }

            ret = RSA_padding_check_PKCS1_OAEP_mgf1(out, (int)outsize, tbuf,

                (int)len, (int)len,

                prsactx->oaep_label,

                (int)prsactx->oaep_labellen,

                prsactx->oaep_md,

                prsactx->mgf1_md);

        } else {

            /* RSA_PKCS1_WITH_TLS_PADDING */

            if (prsactx->client_version <= 0) {

                ERR_raise(ERR_LIB_PROV, PROV_R_BAD_TLS_CLIENT_VERSION);

                OPENSSL_free(tbuf);

                return 0;

            }

            ret = ossl_rsa_padding_check_PKCS1_type_2_TLS(

                prsactx->libctx, out, outsize, tbuf, len,

                prsactx->client_version, prsactx->alt_version);

        }

        OPENSSL_free(tbuf);

    } else {

        if ((prsactx->implicit_rejection == 0) && (prsactx->pad_mode == RSA_PKCS1_PADDING))

            pad_mode = RSA_PKCS1_NO_IMPLICIT_REJECT_PADDING;

        else

            pad_mode = prsactx->pad_mode;

        ret = RSA_private_decrypt((int)inlen, in, out, prsactx->rsa, pad_mode);

    }

    *outlen = constant_time_select_s(constant_time_msb_s(ret), *outlen, ret);

    ret = constant_time_select_int(constant_time_msb(ret), 0, 1);

    return ret;

}

static void rsa_freectx(void *vprsactx)

{

    PROV_RSA_CTX *prsactx = (PROV_RSA_CTX *)vprsactx;

    RSA_free(prsactx->rsa);

    EVP_MD_free(prsactx->oaep_md);

    EVP_MD_free(prsactx->mgf1_md);

    OPENSSL_free(prsactx->oaep_label);

    OPENSSL_free(prsactx);

}

static void *rsa_dupctx(void *vprsactx)

{

    PROV_RSA_CTX *srcctx = (PROV_RSA_CTX *)vprsactx;

    PROV_RSA_CTX *dstctx;

    if (!ossl_prov_is_running())

        return NULL;

    dstctx = OPENSSL_zalloc(sizeof(*srcctx));

    if (dstctx == NULL)

        return NULL;

    *dstctx = *srcctx;

    if (dstctx->rsa != NULL && !RSA_up_ref(dstctx->rsa)) {

        OPENSSL_free(dstctx);

        return NULL;

    }

    if (dstctx->oaep_md != NULL && !EVP_MD_up_ref(dstctx->oaep_md)) {

        RSA_free(dstctx->rsa);

        OPENSSL_free(dstctx);

        return NULL;

    }

    if (dstctx->mgf1_md != NULL && !EVP_MD_up_ref(dstctx->mgf1_md)) {

        RSA_free(dstctx->rsa);

        EVP_MD_free(dstctx->oaep_md);

        OPENSSL_free(dstctx);

        return NULL;

    }

    if (dstctx->oaep_label != NULL

        && (dstctx->oaep_label = OPENSSL_memdup(dstctx->oaep_label, dstctx->oaep_labellen)) == NULL) {

        rsa_freectx(dstctx);

        return NULL;

    }

    return dstctx;

}

static int rsa_get_ctx_params(void *vprsactx, OSSL_PARAM *params)

{

    PROV_RSA_CTX *prsactx = (PROV_RSA_CTX *)vprsactx;

    struct rsa_get_ctx_params_st p;

    if (prsactx == NULL || !rsa_get_ctx_params_decoder(params, &p))

        return 0;

    if (p.pad != NULL) {

        if (p.pad->data_type != OSSL_PARAM_UTF8_STRING) {

            /* Support for legacy pad mode number */

            if (!OSSL_PARAM_set_int(p.pad, prsactx->pad_mode))

                return 0;

        } else {

            int i;

            const char *word = NULL;

            for (i = 0; padding_item[i].id != 0; i++) {

                if (prsactx->pad_mode == (int)padding_item[i].id) {

                    word = padding_item[i].ptr;

                    break;

                }

            }

            if (word != NULL) {

                if (!OSSL_PARAM_set_utf8_string(p.pad, word))

                    return 0;

            } else {

                ERR_raise(ERR_LIB_PROV, ERR_R_INTERNAL_ERROR);

            }

        }

    }

    if (p.oaep != NULL && !OSSL_PARAM_set_utf8_string(p.oaep, prsactx->oaep_md == NULL ? "" : EVP_MD_get0_name(prsactx->oaep_md)))

        return 0;

    if (p.mgf1 != NULL) {

        EVP_MD *mgf1_md = prsactx->mgf1_md == NULL ? prsactx->oaep_md

                                                   : prsactx->mgf1_md;

        if (!OSSL_PARAM_set_utf8_string(p.mgf1, mgf1_md == NULL ? "" : EVP_MD_get0_name(mgf1_md)))

            return 0;

    }

    if (p.label != NULL

        && !OSSL_PARAM_set_octet_ptr(p.label, prsactx->oaep_label,

            prsactx->oaep_labellen))

        return 0;

    if (p.tlsver != NULL

        && !OSSL_PARAM_set_uint(p.tlsver, prsactx->client_version))

        return 0;

    if (p.negver != NULL

        && !OSSL_PARAM_set_uint(p.negver, prsactx->alt_version))

        return 0;

    if (p.imrej != NULL

        && !OSSL_PARAM_set_uint(p.imrej, prsactx->implicit_rejection))

        return 0;

    if (!OSSL_FIPS_IND_GET_CTX_FROM_PARAM(prsactx, p.ind))

        return 0;

    return 1;

}

static const OSSL_PARAM *rsa_gettable_ctx_params(ossl_unused void *vprsactx,

    ossl_unused void *provctx)

{

    return rsa_get_ctx_params_list;

}

static int rsa_set_ctx_params(void *vprsactx, const OSSL_PARAM params[])

{

    PROV_RSA_CTX *prsactx = (PROV_RSA_CTX *)vprsactx;

    struct rsa_set_ctx_params_st p;

    char mdname[OSSL_MAX_NAME_SIZE];

    char mdprops[OSSL_MAX_PROPQUERY_SIZE] = { '\0' };

    char *str = NULL;

    int count = 0;

    if (prsactx == NULL || !rsa_set_ctx_params_decoder(params, &p, &count))

        return 0;

    if (count == 0)

        return 1;

    if (!OSSL_FIPS_IND_SET_CTX_FROM_PARAM(prsactx, OSSL_FIPS_IND_SETTABLE0, p.ind_k))

        return 0;

    if (!OSSL_FIPS_IND_SET_CTX_FROM_PARAM(prsactx, OSSL_FIPS_IND_SETTABLE1, p.ind_pad))

        return 0;

    if (p.oaep != NULL) {

        str = mdname;

        if (!OSSL_PARAM_get_utf8_string(p.oaep, &str, sizeof(mdname)))

            return 0;

        if (p.oaep_pq != NULL) {

            str = mdprops;

            if (!OSSL_PARAM_get_utf8_string(p.oaep_pq, &str, sizeof(mdprops)))

                return 0;

        }

        EVP_MD_free(prsactx->oaep_md);

        prsactx->oaep_md = EVP_MD_fetch(prsactx->libctx, mdname, mdprops);

        if (prsactx->oaep_md == NULL)

            return 0;

    }

    if (p.pad != NULL) {

        int pad_mode = 0;

        if (p.pad->data_type != OSSL_PARAM_UTF8_STRING) {

            /* Support for legacy pad mode as a number */

            if (!OSSL_PARAM_get_int(p.pad, &pad_mode))

                return 0;

        } else {

            int i;

            if (p.pad->data == NULL)

                return 0;

            for (i = 0; padding_item[i].id != 0; i++) {

                if (strcmp(p.pad->data, padding_item[i].ptr) == 0) {

                    pad_mode = padding_item[i].id;

                    break;

                }

            }

        }

        /*

         * PSS padding is for signatures only so is not compatible with

         * asymmetric cipher use.

         */

        if (pad_mode == RSA_PKCS1_PSS_PADDING)

            return 0;

        if (pad_mode == RSA_PKCS1_OAEP_PADDING && prsactx->oaep_md == NULL) {

            prsactx->oaep_md = EVP_MD_fetch(prsactx->libctx, "SHA1", mdprops);

            if (prsactx->oaep_md == NULL)

                return 0;

        }

        prsactx->pad_mode = pad_mode;

    }

    if (p.mgf1 != NULL) {

        str = mdname;

        if (!OSSL_PARAM_get_utf8_string(p.mgf1, &str, sizeof(mdname)))

            return 0;

        if (p.mgf1_pq != NULL) {

            str = mdprops;

            if (!OSSL_PARAM_get_utf8_string(p.mgf1_pq, &str, sizeof(mdprops)))

                return 0;

        } else {

            str = NULL;

        }

        EVP_MD_free(prsactx->mgf1_md);

        prsactx->mgf1_md = EVP_MD_fetch(prsactx->libctx, mdname, str);

        if (prsactx->mgf1_md == NULL)

            return 0;

    }

    if (p.label != NULL) {

        void *tmp_label = NULL;

        size_t tmp_labellen;

        if (!OSSL_PARAM_get_octet_string(p.label, &tmp_label, 0, &tmp_labellen))

            return 0;

        OPENSSL_free(prsactx->oaep_label);

        prsactx->oaep_label = (unsigned char *)tmp_label;

        prsactx->oaep_labellen = tmp_labellen;

    }

    if (p.tlsver != NULL) {

        unsigned int client_version;

        if (!OSSL_PARAM_get_uint(p.tlsver, &client_version))

            return 0;

        prsactx->client_version = client_version;

    }

    if (p.negver != NULL) {

        unsigned int alt_version;

        if (!OSSL_PARAM_get_uint(p.negver, &alt_version))

            return 0;

        prsactx->alt_version = alt_version;

    }

    if (p.imrej != NULL) {

        unsigned int implicit_rejection;

        if (!OSSL_PARAM_get_uint(p.imrej, &implicit_rejection))

            return 0;

        prsactx->implicit_rejection = implicit_rejection;

    }

    return 1;

}

static const OSSL_PARAM *rsa_settable_ctx_params(ossl_unused void *vprsactx,

    ossl_unused void *provctx)

{

    return rsa_set_ctx_params_list;

}

const OSSL_DISPATCH ossl_rsa_asym_cipher_functions[] = {

    { OSSL_FUNC_ASYM_CIPHER_NEWCTX, (void (*)(void))rsa_newctx },

    { OSSL_FUNC_ASYM_CIPHER_ENCRYPT_INIT, (void (*)(void))rsa_encrypt_init },

    { OSSL_FUNC_ASYM_CIPHER_ENCRYPT, (void (*)(void))rsa_encrypt },

    { OSSL_FUNC_ASYM_CIPHER_DECRYPT_INIT, (void (*)(void))rsa_decrypt_init },

    { OSSL_FUNC_ASYM_CIPHER_DECRYPT, (void (*)(void))rsa_decrypt },

    { OSSL_FUNC_ASYM_CIPHER_FREECTX, (void (*)(void))rsa_freectx },

    { OSSL_FUNC_ASYM_CIPHER_DUPCTX, (void (*)(void))rsa_dupctx },

    { OSSL_FUNC_ASYM_CIPHER_GET_CTX_PARAMS,

        (void (*)(void))rsa_get_ctx_params },

    { OSSL_FUNC_ASYM_CIPHER_GETTABLE_CTX_PARAMS,

        (void (*)(void))rsa_gettable_ctx_params },

    { OSSL_FUNC_ASYM_CIPHER_SET_CTX_PARAMS,

        (void (*)(void))rsa_set_ctx_params },

    { OSSL_FUNC_ASYM_CIPHER_SETTABLE_CTX_PARAMS,

        (void (*)(void))rsa_settable_ctx_params },

    OSSL_DISPATCH_END

};