/* Copyright (c) 2014, Google Inc.

 *

 * Permission to use, copy, modify, and/or distribute this software for any

 * purpose with or without fee is hereby granted, provided that the above

 * copyright notice and this permission notice appear in all copies.

 *

 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES

 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF

 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY

 * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES

 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION

 * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN

 * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */

#include <openssl/pkcs7.h>

#include <openssl/bytestring.h>

#include <openssl/err.h>

#include <openssl/mem.h>

#include <openssl/pool.h>

#include <openssl/stack.h>

#include "internal.h"

#include "../bytestring/internal.h"

// 1.2.840.113549.1.7.1

static const uint8_t kPKCS7Data[] = {0x2a, 0x86, 0x48, 0x86, 0xf7,

                                     0x0d, 0x01, 0x07, 0x01};

// 1.2.840.113549.1.7.2

static const uint8_t kPKCS7SignedData[] = {0x2a, 0x86, 0x48, 0x86, 0xf7,

                                           0x0d, 0x01, 0x07, 0x02};

// pkcs7_parse_header reads the non-certificate/non-CRL prefix of a PKCS#7

// SignedData blob from |cbs| and sets |*out| to point to the rest of the

// input. If the input is in BER format, then |*der_bytes| will be set to a

// pointer that needs to be freed by the caller once they have finished

// processing |*out| (which will be pointing into |*der_bytes|).

//

// It returns one on success or zero on error. On error, |*der_bytes| is

// NULL.

int pkcs7_parse_header(uint8_t **der_bytes, CBS *out, CBS *cbs) {

  CBS in, content_info, content_type, wrapped_signed_data, signed_data;

  uint64_t version;

  // The input may be in BER format.

  *der_bytes = NULL;

  if (!CBS_asn1_ber_to_der(cbs, &in, der_bytes) ||

      // See https://tools.ietf.org/html/rfc2315#section-7

      !CBS_get_asn1(&in, &content_info, CBS_ASN1_SEQUENCE) ||

      !CBS_get_asn1(&content_info, &content_type, CBS_ASN1_OBJECT)) {

    goto err;

  }

  if (!CBS_mem_equal(&content_type, kPKCS7SignedData,

                     sizeof(kPKCS7SignedData))) {

    OPENSSL_PUT_ERROR(PKCS7, PKCS7_R_NOT_PKCS7_SIGNED_DATA);

    goto err;

  }

  // See https://tools.ietf.org/html/rfc2315#section-9.1

  if (!CBS_get_asn1(&content_info, &wrapped_signed_data,

                    CBS_ASN1_CONTEXT_SPECIFIC | CBS_ASN1_CONSTRUCTED | 0) ||

      !CBS_get_asn1(&wrapped_signed_data, &signed_data, CBS_ASN1_SEQUENCE) ||

      !CBS_get_asn1_uint64(&signed_data, &version) ||

      !CBS_get_asn1(&signed_data, NULL /* digests */, CBS_ASN1_SET) ||

      !CBS_get_asn1(&signed_data, NULL /* content */, CBS_ASN1_SEQUENCE)) {

    goto err;

  }

  if (version < 1) {

    OPENSSL_PUT_ERROR(PKCS7, PKCS7_R_BAD_PKCS7_VERSION);

    goto err;

  }

  CBS_init(out, CBS_data(&signed_data), CBS_len(&signed_data));

  return 1;

err:

  OPENSSL_free(*der_bytes);

  *der_bytes = NULL;

  return 0;

}

int PKCS7_get_raw_certificates(STACK_OF(CRYPTO_BUFFER) *out_certs, CBS *cbs,

                               CRYPTO_BUFFER_POOL *pool) {

  CBS signed_data, certificates;

  uint8_t *der_bytes = NULL;

  int ret = 0, has_certificates;

  const size_t initial_certs_len = sk_CRYPTO_BUFFER_num(out_certs);

  // See https://tools.ietf.org/html/rfc2315#section-9.1

  if (!pkcs7_parse_header(&der_bytes, &signed_data, cbs) ||

      !CBS_get_optional_asn1(

          &signed_data, &certificates, &has_certificates,

          CBS_ASN1_CONTEXT_SPECIFIC | CBS_ASN1_CONSTRUCTED | 0)) {

    goto err;

  }

  if (!has_certificates) {

    CBS_init(&certificates, NULL, 0);

  }

  while (CBS_len(&certificates) > 0) {

    CBS cert;

    if (!CBS_get_asn1_element(&certificates, &cert, CBS_ASN1_SEQUENCE)) {

      goto err;

    }

    CRYPTO_BUFFER *buf = CRYPTO_BUFFER_new_from_CBS(&cert, pool);

    if (buf == NULL ||

        !sk_CRYPTO_BUFFER_push(out_certs, buf)) {

      CRYPTO_BUFFER_free(buf);

      goto err;

    }

  }

  ret = 1;

err:

  OPENSSL_free(der_bytes);

  if (!ret) {

    while (sk_CRYPTO_BUFFER_num(out_certs) != initial_certs_len) {

      CRYPTO_BUFFER *buf = sk_CRYPTO_BUFFER_pop(out_certs);

      CRYPTO_BUFFER_free(buf);

    }

  }

  return ret;

}

static int pkcs7_bundle_raw_certificates_cb(CBB *out, const void *arg) {

  const STACK_OF(CRYPTO_BUFFER) *certs = arg;

  CBB certificates;

  // See https://tools.ietf.org/html/rfc2315#section-9.1

  if (!CBB_add_asn1(out, &certificates,

                    CBS_ASN1_CONTEXT_SPECIFIC | CBS_ASN1_CONSTRUCTED | 0)) {

    return 0;

  }

  for (size_t i = 0; i < sk_CRYPTO_BUFFER_num(certs); i++) {

    CRYPTO_BUFFER *cert = sk_CRYPTO_BUFFER_value(certs, i);

    if (!CBB_add_bytes(&certificates, CRYPTO_BUFFER_data(cert),

                       CRYPTO_BUFFER_len(cert))) {

      return 0;

    }

  }

  // |certificates| is a implicitly-tagged SET OF.

  return CBB_flush_asn1_set_of(&certificates) && CBB_flush(out);

}

int PKCS7_bundle_raw_certificates(CBB *out,

                                  const STACK_OF(CRYPTO_BUFFER) *certs) {

  return pkcs7_add_signed_data(out, /*digest_algos_cb=*/NULL,

                               pkcs7_bundle_raw_certificates_cb,

                               /*signer_infos_cb=*/NULL, certs);

}

int pkcs7_add_signed_data(CBB *out,

                          int (*digest_algos_cb)(CBB *out, const void *arg),

                          int (*cert_crl_cb)(CBB *out, const void *arg),

                          int (*signer_infos_cb)(CBB *out, const void *arg),

                          const void *arg) {

  CBB outer_seq, oid, wrapped_seq, seq, version_bytes, digest_algos_set,

      content_info, signer_infos;

  // See https://tools.ietf.org/html/rfc2315#section-7

  if (!CBB_add_asn1(out, &outer_seq, CBS_ASN1_SEQUENCE) ||

      !CBB_add_asn1(&outer_seq, &oid, CBS_ASN1_OBJECT) ||

      !CBB_add_bytes(&oid, kPKCS7SignedData, sizeof(kPKCS7SignedData)) ||

      !CBB_add_asn1(&outer_seq, &wrapped_seq,

                    CBS_ASN1_CONTEXT_SPECIFIC | CBS_ASN1_CONSTRUCTED | 0) ||

      // See https://tools.ietf.org/html/rfc2315#section-9.1

      !CBB_add_asn1(&wrapped_seq, &seq, CBS_ASN1_SEQUENCE) ||

      !CBB_add_asn1(&seq, &version_bytes, CBS_ASN1_INTEGER) ||

      !CBB_add_u8(&version_bytes, 1) ||

      !CBB_add_asn1(&seq, &digest_algos_set, CBS_ASN1_SET) ||

      (digest_algos_cb != NULL && !digest_algos_cb(&digest_algos_set, arg)) ||

      !CBB_add_asn1(&seq, &content_info, CBS_ASN1_SEQUENCE) ||

      !CBB_add_asn1(&content_info, &oid, CBS_ASN1_OBJECT) ||

      !CBB_add_bytes(&oid, kPKCS7Data, sizeof(kPKCS7Data)) ||

      (cert_crl_cb != NULL && !cert_crl_cb(&seq, arg)) ||

      !CBB_add_asn1(&seq, &signer_infos, CBS_ASN1_SET) ||

      (signer_infos_cb != NULL && !signer_infos_cb(&signer_infos, arg))) {

    return 0;

  }

  return CBB_flush(out);

}