/*

 * Copyright 2016-2021 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

 */

#include <limits.h>

#include <string.h>

#include <openssl/ct.h>

#include <openssl/err.h>

#include <openssl/evp.h>

#include "ct_local.h"

/*

 * Decodes the base64 string |in| into |out|.

 * A new string will be malloc'd and assigned to |out|. This will be owned by

 * the caller. Do not provide a pre-allocated string in |out|.

 */

static int ct_base64_decode(const char *in, unsigned char **out)

{

    size_t inlen = strlen(in);

    int outlen, i;

    unsigned char *outbuf = NULL;

    if (inlen == 0) {

        *out = NULL;

        return 0;

    }

    outlen = (inlen / 4) * 3;

    outbuf = OPENSSL_malloc(outlen);

    if (outbuf == NULL)

        goto err;

    outlen = EVP_DecodeBlock(outbuf, (unsigned char *)in, inlen);

    if (outlen < 0) {

        ERR_raise(ERR_LIB_CT, CT_R_BASE64_DECODE_ERROR);

        goto err;

    }

    /* Subtract padding bytes from |outlen|.  Any more than 2 is malformed. */

    i = 0;

    while (in[--inlen] == '=') {

        --outlen;

        if (++i > 2)

            goto err;

    }

    *out = outbuf;

    return outlen;

err:

    OPENSSL_free(outbuf);

    return -1;

}

SCT *SCT_new_from_base64(unsigned char version, const char *logid_base64,

                         ct_log_entry_type_t entry_type, uint64_t timestamp,

                         const char *extensions_base64,

                         const char *signature_base64)

{

    SCT *sct = SCT_new();

    unsigned char *dec = NULL;

    const unsigned char* p = NULL;

    int declen;

    if (sct == NULL) {

        ERR_raise(ERR_LIB_CT, ERR_R_CT_LIB);

        return NULL;

    }

    /*

     * RFC6962 section 4.1 says we "MUST NOT expect this to be 0", but we

     * can only construct SCT versions that have been defined.

     */

    if (!SCT_set_version(sct, version)) {

        ERR_raise(ERR_LIB_CT, CT_R_SCT_UNSUPPORTED_VERSION);

        goto err;

    }

    declen = ct_base64_decode(logid_base64, &dec);

    if (declen < 0) {

        ERR_raise(ERR_LIB_CT, X509_R_BASE64_DECODE_ERROR);

        goto err;

    }

    if (!SCT_set0_log_id(sct, dec, declen))

        goto err;

    dec = NULL;

    declen = ct_base64_decode(extensions_base64, &dec);

    if (declen < 0) {

        ERR_raise(ERR_LIB_CT, X509_R_BASE64_DECODE_ERROR);

        goto err;

    }

    SCT_set0_extensions(sct, dec, declen);

    dec = NULL;

    declen = ct_base64_decode(signature_base64, &dec);

    if (declen < 0) {

        ERR_raise(ERR_LIB_CT, X509_R_BASE64_DECODE_ERROR);

        goto err;

    }

    p = dec;

    if (o2i_SCT_signature(sct, &p, declen) <= 0)

        goto err;

    OPENSSL_free(dec);

    dec = NULL;

    SCT_set_timestamp(sct, timestamp);

    if (!SCT_set_log_entry_type(sct, entry_type))

        goto err;

    return sct;

 err:

    OPENSSL_free(dec);

    SCT_free(sct);

    return NULL;

}

/*

 * Allocate, build and returns a new |ct_log| from input |pkey_base64|

 * It returns 1 on success,

 * 0 on decoding failure, or invalid parameter if any

 * -1 on internal (malloc) failure

 */

int CTLOG_new_from_base64_ex(CTLOG **ct_log, const char *pkey_base64,

                             const char *name, OSSL_LIB_CTX *libctx,

                             const char *propq)

{

    unsigned char *pkey_der = NULL;

    int pkey_der_len;

    const unsigned char *p;

    EVP_PKEY *pkey = NULL;

    if (ct_log == NULL) {

        ERR_raise(ERR_LIB_CT, ERR_R_PASSED_INVALID_ARGUMENT);

        return 0;

    }

    pkey_der_len = ct_base64_decode(pkey_base64, &pkey_der);

    if (pkey_der_len < 0) {

        ERR_raise(ERR_LIB_CT, CT_R_LOG_CONF_INVALID_KEY);

        return 0;

    }

    p = pkey_der;

    pkey = d2i_PUBKEY_ex(NULL, &p, pkey_der_len, libctx, propq);

    OPENSSL_free(pkey_der);

    if (pkey == NULL) {

        ERR_raise(ERR_LIB_CT, CT_R_LOG_CONF_INVALID_KEY);

        return 0;

    }

    *ct_log = CTLOG_new_ex(pkey, name, libctx, propq);

    if (*ct_log == NULL) {

        EVP_PKEY_free(pkey);

        return 0;

    }

    return 1;

}

int CTLOG_new_from_base64(CTLOG **ct_log, const char *pkey_base64,

                          const char *name)

{

    return CTLOG_new_from_base64_ex(ct_log, pkey_base64, name, NULL, NULL);

}