/*

 * Copyright 2020-2025 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 <string.h>

#include <openssl/core_dispatch.h>

#include <openssl/core_names.h>

#include <openssl/core_object.h>

#include <openssl/crypto.h>

#include <openssl/err.h>

#include <openssl/params.h>

#include <openssl/pem.h>

#include <openssl/proverr.h>

#include "internal/nelem.h"

#include "prov/bio.h"

#include "prov/implementations.h"

#include "endecoder_local.h"

static int read_pem(PROV_CTX *provctx, OSSL_CORE_BIO *cin,

    char **pem_name, char **pem_header,

    unsigned char **data, long *len)

{

    BIO *in = ossl_bio_new_from_core_bio(provctx, cin);

    int ok;

    if (in == NULL)

        return 0;

    ok = (PEM_read_bio(in, pem_name, pem_header, data, len) > 0);

    BIO_free(in);

    return ok;

}

static OSSL_FUNC_decoder_newctx_fn pem2der_newctx;

static OSSL_FUNC_decoder_freectx_fn pem2der_freectx;

static OSSL_FUNC_decoder_decode_fn pem2der_decode;

/*

 * Context used for PEM to DER decoding.

 */

struct pem2der_ctx_st {

    PROV_CTX *provctx;

};

static void *pem2der_newctx(void *provctx)

{

    struct pem2der_ctx_st *ctx = OPENSSL_zalloc(sizeof(*ctx));

    if (ctx != NULL)

        ctx->provctx = provctx;

    return ctx;

}

static void pem2der_freectx(void *vctx)

{

    struct pem2der_ctx_st *ctx = vctx;

    OPENSSL_free(ctx);

}

/* pem_password_cb compatible function */

struct pem2der_pass_data_st {

    OSSL_PASSPHRASE_CALLBACK *cb;

    void *cbarg;

};

static int pem2der_pass_helper(char *buf, int num, int w, void *data)

{

    struct pem2der_pass_data_st *pass_data = data;

    size_t plen;

    if (pass_data == NULL

        || pass_data->cb == NULL

        || !pass_data->cb(buf, num, &plen, NULL, pass_data->cbarg))

        return -1;

    return (int)plen;

}

/*

 * The selection parameter in pem2der_decode() is not used by this function

 * because it's not relevant just to decode PEM to DER.

 */

static int pem2der_decode(void *vctx, OSSL_CORE_BIO *cin, int selection,

    OSSL_CALLBACK *data_cb, void *data_cbarg,

    OSSL_PASSPHRASE_CALLBACK *pw_cb, void *pw_cbarg)

{

    /*

     * PEM names we recognise.  Other PEM names should be recognised by

     * other decoder implementations.

     */

    static struct pem_name_map_st {

        const char *pem_name;

        int object_type;

        const char *data_type;

        const char *data_structure;

    } pem_name_map[] = {

        /* PKCS#8 and SubjectPublicKeyInfo */

        { PEM_STRING_PKCS8, OSSL_OBJECT_PKEY, NULL, "EncryptedPrivateKeyInfo" },

        { PEM_STRING_PKCS8INF, OSSL_OBJECT_PKEY, NULL, "PrivateKeyInfo" },

        { PEM_STRING_PUBLIC, OSSL_OBJECT_PKEY, NULL, "SubjectPublicKeyInfo" },

        /* Our set of type specific PEM types */

        { PEM_STRING_DHPARAMS, OSSL_OBJECT_PKEY, "DH", "type-specific" },

        { PEM_STRING_DHXPARAMS, OSSL_OBJECT_PKEY, "X9.42 DH", "type-specific" },

        { PEM_STRING_DSA, OSSL_OBJECT_PKEY, "DSA", "type-specific" },

        { PEM_STRING_DSA_PUBLIC, OSSL_OBJECT_PKEY, "DSA", "type-specific" },

        { PEM_STRING_DSAPARAMS, OSSL_OBJECT_PKEY, "DSA", "type-specific" },

        { PEM_STRING_ECPRIVATEKEY, OSSL_OBJECT_PKEY, "EC", "type-specific" },

        { PEM_STRING_ECPARAMETERS, OSSL_OBJECT_PKEY, "EC", "type-specific" },

        { PEM_STRING_SM2PRIVATEKEY, OSSL_OBJECT_PKEY, "SM2", "type-specific" },

        { PEM_STRING_SM2PARAMETERS, OSSL_OBJECT_PKEY, "SM2", "type-specific" },

        { PEM_STRING_RSA, OSSL_OBJECT_PKEY, "RSA", "type-specific" },

        { PEM_STRING_RSA_PUBLIC, OSSL_OBJECT_PKEY, "RSA", "type-specific" },

        /*

         * A few others that there is at least have an object type for, even

         * though there is no provider interface to handle such objects, yet.

         * However, this is beneficial for the OSSL_STORE result handler.

         */

        { PEM_STRING_X509, OSSL_OBJECT_CERT, NULL, "Certificate" },

        { PEM_STRING_X509_TRUSTED, OSSL_OBJECT_CERT, NULL, "Certificate" },

        { PEM_STRING_X509_OLD, OSSL_OBJECT_CERT, NULL, "Certificate" },

        { PEM_STRING_X509_CRL, OSSL_OBJECT_CRL, NULL, "CertificateList" }

    };

    struct pem2der_ctx_st *ctx = vctx;

    char *pem_name = NULL, *pem_header = NULL;

    size_t i;

    unsigned char *der = NULL;

    long der_len = 0;

    int ok = 0;

    int objtype = OSSL_OBJECT_UNKNOWN;

    ok = read_pem(ctx->provctx, cin, &pem_name, &pem_header,

             &der, &der_len)

        > 0;

    /* We return "empty handed".  This is not an error. */

    if (!ok)

        return 1;

    /*

     * 10 is the number of characters in "Proc-Type:", which

     * PEM_get_EVP_CIPHER_INFO() requires to be present.

     * If the PEM header has less characters than that, it's

     * not worth spending cycles on it.

     */

    if (strlen(pem_header) > 10) {

        EVP_CIPHER_INFO cipher;

        struct pem2der_pass_data_st pass_data;

        ok = 0; /* Assume that we fail */

        pass_data.cb = pw_cb;

        pass_data.cbarg = pw_cbarg;

        if (!PEM_get_EVP_CIPHER_INFO(pem_header, &cipher)

            || !PEM_do_header(&cipher, der, &der_len,

                pem2der_pass_helper, &pass_data))

            goto end;

    }

    /*

     * Indicated that we successfully decoded something, or not at all.

     * Ending up "empty handed" is not an error.

     */

    ok = 1;

    /* Have a look to see if we recognise anything */

    for (i = 0; i < OSSL_NELEM(pem_name_map); i++)

        if (strcmp(pem_name, pem_name_map[i].pem_name) == 0)

            break;

    if (i < OSSL_NELEM(pem_name_map)) {

        OSSL_PARAM params[5], *p = params;

        /* We expect these to be read only so casting away the const is ok */

        char *data_type = (char *)pem_name_map[i].data_type;

        char *data_structure = (char *)pem_name_map[i].data_structure;

        objtype = pem_name_map[i].object_type;

        if (data_type != NULL)

            *p++ = OSSL_PARAM_construct_utf8_string(OSSL_OBJECT_PARAM_DATA_TYPE,

                data_type, 0);

        /* We expect this to be read only so casting away the const is ok */

        if (data_structure != NULL)

            *p++ = OSSL_PARAM_construct_utf8_string(OSSL_OBJECT_PARAM_DATA_STRUCTURE,

                data_structure, 0);

        *p++ = OSSL_PARAM_construct_octet_string(OSSL_OBJECT_PARAM_DATA,

            der, der_len);

        *p++ = OSSL_PARAM_construct_int(OSSL_OBJECT_PARAM_TYPE, &objtype);

        *p = OSSL_PARAM_construct_end();

        ok = data_cb(params, data_cbarg);

    }

end:

    OPENSSL_free(pem_name);

    OPENSSL_free(pem_header);

    OPENSSL_free(der);

    return ok;

}

const OSSL_DISPATCH ossl_pem_to_der_decoder_functions[] = {

    { OSSL_FUNC_DECODER_NEWCTX, (void (*)(void))pem2der_newctx },

    { OSSL_FUNC_DECODER_FREECTX, (void (*)(void))pem2der_freectx },

    { OSSL_FUNC_DECODER_DECODE, (void (*)(void))pem2der_decode },

    OSSL_DISPATCH_END

};