/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
 * All rights reserved.
 *
 * This package is an SSL implementation written
 * by Eric Young (eay@cryptsoft.com).
 * The implementation was written so as to conform with Netscapes SSL.
 *
 * This library is free for commercial and non-commercial use as long as
 * the following conditions are aheared to.  The following conditions
 * apply to all code found in this distribution, be it the RC4, RSA,
 * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
 * included with this distribution is covered by the same copyright terms
 * except that the holder is Tim Hudson (tjh@cryptsoft.com).
 *
 * Copyright remains Eric Young's, and as such any Copyright notices in
 * the code are not to be removed.
 * If this package is used in a product, Eric Young should be given attribution
 * as the author of the parts of the library used.
 * This can be in the form of a textual message at program startup or
 * in documentation (online or textual) provided with the package.
 *
 * 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 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 acknowledgement:
 *    "This product includes cryptographic software written by
 *     Eric Young (eay@cryptsoft.com)"
 *    The word 'cryptographic' can be left out if the rouines from the library
 *    being used are not cryptographic related :-).
 * 4. If you include any Windows specific code (or a derivative thereof) from
 *    the apps directory (application code) you must include an acknowledgement:
 *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
 *
 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
 * ANY EXPRESS 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 AUTHOR OR 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.
 *
 * The licence and distribution terms for any publically available version or
 * derivative of this code cannot be changed.  i.e. this code cannot simply be
 * copied and put under another distribution licence
 * [including the GNU Public Licence.]
 */

#include <openssl/pem.h>

#include <assert.h>
#include <stdio.h>
#include <string.h>

#include <openssl/dsa.h>
#include <openssl/err.h>
#include <openssl/evp.h>
#include <openssl/mem.h>
#include <openssl/obj.h>
#include <openssl/rsa.h>
#include <openssl/x509.h>

STACK_OF(X509_INFO) *PEM_X509_INFO_read(FILE *fp, STACK_OF(X509_INFO) *sk,
                                        pem_password_cb *cb, void *u) {
  BIO *b = BIO_new_fp(fp, BIO_NOCLOSE);
  if (b == NULL) {
    OPENSSL_PUT_ERROR(PEM, ERR_R_BUF_LIB);
    return 0;
  }
  STACK_OF(X509_INFO) *ret = PEM_X509_INFO_read_bio(b, sk, cb, u);
  BIO_free(b);
  return ret;
}

enum parse_result_t {
  parse_ok,
  parse_error,
  parse_new_entry,
};

static enum parse_result_t parse_x509(X509_INFO *info, const uint8_t *data,
                                      size_t len, int key_type) {
  if (info->x509 != NULL) {
    return parse_new_entry;
  }
  info->x509 = d2i_X509(NULL, &data, len);
  return info->x509 != NULL ? parse_ok : parse_error;
}

static enum parse_result_t parse_x509_aux(X509_INFO *info, const uint8_t *data,
                                          size_t len, int key_type) {
  if (info->x509 != NULL) {
    return parse_new_entry;
  }
  info->x509 = d2i_X509_AUX(NULL, &data, len);
  return info->x509 != NULL ? parse_ok : parse_error;
}

static enum parse_result_t parse_crl(X509_INFO *info, const uint8_t *data,
                                     size_t len, int key_type) {
  if (info->crl != NULL) {
    return parse_new_entry;
  }
  info->crl = d2i_X509_CRL(NULL, &data, len);
  return info->crl != NULL ? parse_ok : parse_error;
}

static enum parse_result_t parse_key(X509_INFO *info, const uint8_t *data,
                                     size_t len, int key_type) {
  if (info->x_pkey != NULL) {
    return parse_new_entry;
  }
  info->x_pkey = X509_PKEY_new();
  if (info->x_pkey == NULL) {
    return parse_error;
  }
  info->x_pkey->dec_pkey = d2i_PrivateKey(key_type, NULL, &data, len);
  return info->x_pkey->dec_pkey != NULL ? parse_ok : parse_error;
}

STACK_OF(X509_INFO) *PEM_X509_INFO_read_bio(BIO *bp, STACK_OF(X509_INFO) *sk,
                                            pem_password_cb *cb, void *u) {
  X509_INFO *info = NULL;
  char *name = NULL, *header = NULL;
  unsigned char *data = NULL;
  long len;
  int ok = 0;
  STACK_OF(X509_INFO) *ret = NULL;

  if (sk == NULL) {
    ret = sk_X509_INFO_new_null();
    if (ret == NULL) {
      return NULL;
    }
  } else {
    ret = sk;
  }
  size_t orig_num = sk_X509_INFO_num(ret);

  info = X509_INFO_new();
  if (info == NULL) {
    goto err;
  }

  for (;;) {
    if (!PEM_read_bio(bp, &name, &header, &data, &len)) {
      uint32_t error = ERR_peek_last_error();
      if (ERR_GET_LIB(error) == ERR_LIB_PEM &&
          ERR_GET_REASON(error) == PEM_R_NO_START_LINE) {
        ERR_clear_error();
        break;
      }
      goto err;
    }

    enum parse_result_t (*parse_function)(X509_INFO *, const uint8_t *, size_t,
                                          int) = NULL;
    int key_type = EVP_PKEY_NONE;
    if (strcmp(name, PEM_STRING_X509) == 0 ||
        strcmp(name, PEM_STRING_X509_OLD) == 0) {
      parse_function = parse_x509;
    } else if (strcmp(name, PEM_STRING_X509_TRUSTED) == 0) {
      parse_function = parse_x509_aux;
    } else if (strcmp(name, PEM_STRING_X509_CRL) == 0) {
      parse_function = parse_crl;
    } else if (strcmp(name, PEM_STRING_RSA) == 0) {
      parse_function = parse_key;
      key_type = EVP_PKEY_RSA;
    } else if (strcmp(name, PEM_STRING_DSA) == 0) {
      parse_function = parse_key;
      key_type = EVP_PKEY_DSA;
    } else if (strcmp(name, PEM_STRING_ECPRIVATEKEY) == 0) {
      parse_function = parse_key;
      key_type = EVP_PKEY_EC;
    }

    // If a private key has a header, assume it is encrypted.
    if (key_type != EVP_PKEY_NONE && strlen(header) > 10) {
      if (info->x_pkey != NULL) {
        if (!sk_X509_INFO_push(ret, info)) {
          goto err;
        }
        info = X509_INFO_new();
        if (info == NULL) {
          goto err;
        }
      }
      // Historically, raw entries pushed an empty key.
      info->x_pkey = X509_PKEY_new();
      if (info->x_pkey == NULL ||
          !PEM_get_EVP_CIPHER_INFO(header, &info->enc_cipher)) {
        goto err;
      }
      info->enc_data = (char *)data;
      info->enc_len = (int)len;
      data = NULL;
    } else if (parse_function != NULL) {
      EVP_CIPHER_INFO cipher;
      if (!PEM_get_EVP_CIPHER_INFO(header, &cipher) ||
          !PEM_do_header(&cipher, data, &len, cb, u)) {
        goto err;
      }
      enum parse_result_t result = parse_function(info, data, len, key_type);
      if (result == parse_new_entry) {
        if (!sk_X509_INFO_push(ret, info)) {
          goto err;
        }
        info = X509_INFO_new();
        if (info == NULL) {
          goto err;
        }
        result = parse_function(info, data, len, key_type);
      }
      if (result != parse_ok) {
        OPENSSL_PUT_ERROR(PEM, ERR_R_ASN1_LIB);
        goto err;
      }
    }
    OPENSSL_free(name);
    OPENSSL_free(header);
    OPENSSL_free(data);
    name = NULL;
    header = NULL;
    data = NULL;
  }

  // Push the last entry on the stack if not empty.
  if (info->x509 != NULL || info->crl != NULL || info->x_pkey != NULL ||
      info->enc_data != NULL) {
    if (!sk_X509_INFO_push(ret, info)) {
      goto err;
    }
    info = NULL;
  }

  ok = 1;

err:
  X509_INFO_free(info);
  if (!ok) {
    while (sk_X509_INFO_num(ret) > orig_num) {
      X509_INFO_free(sk_X509_INFO_pop(ret));
    }
    if (ret != sk) {
      sk_X509_INFO_free(ret);
    }
    ret = NULL;
  }

  OPENSSL_free(name);
  OPENSSL_free(header);
  OPENSSL_free(data);
  return ret;
}