/*
 * Written by Rob Stradling (rob@comodo.com) and Stephen Henson
 * (steve@openssl.org) for the OpenSSL project 2014.
 */
/* ====================================================================
 * Copyright (c) 2014 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 <string.h>

#include <openssl/ct.h>
#include <openssl/err.h>
#include <openssl/evp.h>

/*
 * TODO(robpercival): These macros are getting duplicated all over the place.
 * Is there a single place they should be defined for re-use?
 * Also, is there a good reason they aren't functions?
 */
#define n2s(c,s) ((s=(((unsigned int)((c)[0]))<<8) | \
                     (((unsigned int)((c)[1])))), \
                  c+=2)

/*
 * 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;
    unsigned char *outbuf = NULL;

    if (inlen == 0) {
        *out = NULL;
        return 0;
    }

    outlen = (inlen / 4) * 3;
    outbuf = OPENSSL_malloc(outlen);
    if (outbuf == NULL) {
        CTerr(CT_F_CT_BASE64_DECODE, ERR_R_MALLOC_FAILURE);
        goto err;
    }

    outlen = EVP_DecodeBlock(outbuf, (unsigned char *)in, inlen);
    if (outlen < 0) {
        CTerr(CT_F_CT_BASE64_DECODE, CT_R_BASE64_DECODE_ERROR);
        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;
    int declen;

    if (sct == NULL) {
        CTerr(CT_F_SCT_NEW_FROM_BASE64, ERR_R_MALLOC_FAILURE);
        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)) {
        CTerr(CT_F_SCT_NEW_FROM_BASE64, CT_R_SCT_UNSUPPORTED_VERSION);
        goto err;
    }

    declen = ct_base64_decode(logid_base64, &dec);
    if (declen < 0) {
        CTerr(CT_F_SCT_NEW_FROM_BASE64, 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) {
        CTerr(CT_F_SCT_NEW_FROM_BASE64, 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) {
        CTerr(CT_F_SCT_NEW_FROM_BASE64, X509_R_BASE64_DECODE_ERROR);
        goto err;
    }
    if (o2i_SCT_signature(sct, (const unsigned char **)&dec, 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;
}

CTLOG *CTLOG_new_from_base64(const char *pkey_base64, const char *name)
{
    unsigned char *pkey_der = NULL;
    int pkey_der_len = ct_base64_decode(pkey_base64, &pkey_der);
    const unsigned char *p;
    EVP_PKEY *pkey = NULL;
    CTLOG *log = NULL;

    if (pkey_der_len <= 0) {
        CTerr(CT_F_CTLOG_NEW_FROM_BASE64, CT_R_LOG_CONF_INVALID_KEY);
        return NULL;
    }

    p = pkey_der;
    pkey = d2i_PUBKEY(NULL, &p, pkey_der_len);
    OPENSSL_free(pkey_der);
    if (pkey == NULL) {
        CTerr(CT_F_CTLOG_NEW_FROM_BASE64, CT_R_LOG_CONF_INVALID_KEY);
        return NULL;
    }

    log = CTLOG_new(pkey, name);
    if (log == NULL) {
        EVP_PKEY_free(pkey);
        return NULL;
    }

    return log;
}