text: /* Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL
   * project 1999.
   */
  /* ====================================================================
   * Copyright (c) 1999 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 <openssl/pkcs8.h>
  
  #include <limits.h>
  
  #include <openssl/asn1t.h>
  #include <openssl/asn1.h>
  #include <openssl/bio.h>
  #include <openssl/buf.h>
  #include <openssl/bytestring.h>
  #include <openssl/err.h>
  #include <openssl/evp.h>
  #include <openssl/digest.h>
  #include <openssl/hmac.h>
  #include <openssl/mem.h>
  #include <openssl/rand.h>
  #include <openssl/x509.h>
  
  #include "internal.h"
  #include "../bytestring/internal.h"
  #include "../internal.h"
  
  
  int pkcs12_iterations_acceptable(uint64_t iterations) {
  #if defined(BORINGSSL_UNSAFE_FUZZER_MODE)
    static const uint64_t kIterationsLimit = 2048;
  #else
    // Windows imposes a limit of 600K. Mozilla say: “so them increasing
    // maximum to something like 100M or 1G (to have few decades of breathing
    // room) would be very welcome”[1]. So here we set the limit to 100M.
    //
    // [1] https://bugzilla.mozilla.org/show_bug.cgi?id=1436873#c14
    static const uint64_t kIterationsLimit = 100 * 1000000;
  #endif
  
    return 0 < iterations && iterations <= kIterationsLimit;
  }
  
  // Minor tweak to operation: zero private key data
  static int pkey_cb(int operation, ASN1_VALUE **pval, const ASN1_ITEM *it,
                     void *exarg) {
    // Since the structure must still be valid use ASN1_OP_FREE_PRE
    if (operation == ASN1_OP_FREE_PRE) {
      PKCS8_PRIV_KEY_INFO *key = (PKCS8_PRIV_KEY_INFO *)*pval;
      if (key->pkey) {
        OPENSSL_cleanse(key->pkey->data, key->pkey->length);
      }
    }
    return 1;
  }
  
  ASN1_SEQUENCE_cb(PKCS8_PRIV_KEY_INFO, pkey_cb) = {
    ASN1_SIMPLE(PKCS8_PRIV_KEY_INFO, version, ASN1_INTEGER),
    ASN1_SIMPLE(PKCS8_PRIV_KEY_INFO, pkeyalg, X509_ALGOR),
    ASN1_SIMPLE(PKCS8_PRIV_KEY_INFO, pkey, ASN1_OCTET_STRING),
    ASN1_IMP_SET_OF_OPT(PKCS8_PRIV_KEY_INFO, attributes, X509_ATTRIBUTE, 0)
  } ASN1_SEQUENCE_END_cb(PKCS8_PRIV_KEY_INFO, PKCS8_PRIV_KEY_INFO)
  
  IMPLEMENT_ASN1_FUNCTIONS(PKCS8_PRIV_KEY_INFO)
  
  int PKCS8_pkey_set0(PKCS8_PRIV_KEY_INFO *priv, ASN1_OBJECT *aobj, int version,
                      int ptype, void *pval, uint8_t *penc, int penclen) {
    if (version >= 0 &&
        !ASN1_INTEGER_set(priv->version, version)) {
      return 0;
    }
  
    if (!X509_ALGOR_set0(priv->pkeyalg, aobj, ptype, pval)) {
      return 0;
    }
  
    if (penc != NULL) {
      ASN1_STRING_set0(priv->pkey, penc, penclen);
    }
  
    return 1;
  }
  
  int PKCS8_pkey_get0(ASN1_OBJECT **ppkalg, const uint8_t **pk, int *ppklen,
                      X509_ALGOR **pa, PKCS8_PRIV_KEY_INFO *p8) {
    if (ppkalg) {
      *ppkalg = p8->pkeyalg->algorithm;
    }
    if (pk) {
      *pk = ASN1_STRING_data(p8->pkey);
      *ppklen = ASN1_STRING_length(p8->pkey);
    }
    if (pa) {
      *pa = p8->pkeyalg;
    }
    return 1;
  }
  
  EVP_PKEY *EVP_PKCS82PKEY(PKCS8_PRIV_KEY_INFO *p8) {
    uint8_t *der = NULL;
    int der_len = i2d_PKCS8_PRIV_KEY_INFO(p8, &der);
    if (der_len < 0) {
      return NULL;
    }
  
    CBS cbs;
    CBS_init(&cbs, der, (size_t)der_len);
    EVP_PKEY *ret = EVP_parse_private_key(&cbs);
    if (ret == NULL || CBS_len(&cbs) != 0) {
      OPENSSL_PUT_ERROR(PKCS8, PKCS8_R_DECODE_ERROR);
      EVP_PKEY_free(ret);
      OPENSSL_free(der);
      return NULL;
    }
  
    OPENSSL_free(der);
    return ret;
  }
  
  PKCS8_PRIV_KEY_INFO *EVP_PKEY2PKCS8(EVP_PKEY *pkey) {
    CBB cbb;
    uint8_t *der = NULL;
    size_t der_len;
    if (!CBB_init(&cbb, 0) ||
        !EVP_marshal_private_key(&cbb, pkey) ||
        !CBB_finish(&cbb, &der, &der_len) ||
        der_len > LONG_MAX) {
      CBB_cleanup(&cbb);
      OPENSSL_PUT_ERROR(PKCS8, PKCS8_R_ENCODE_ERROR);
      goto err;
    }
  
    const uint8_t *p = der;
    PKCS8_PRIV_KEY_INFO *p8 = d2i_PKCS8_PRIV_KEY_INFO(NULL, &p, (long)der_len);
    if (p8 == NULL || p != der + der_len) {
      PKCS8_PRIV_KEY_INFO_free(p8);
      OPENSSL_PUT_ERROR(PKCS8, PKCS8_R_DECODE_ERROR);
      goto err;
    }
  
    OPENSSL_free(der);
    return p8;
  
  err:
    OPENSSL_free(der);
    return NULL;
  }
  
  PKCS8_PRIV_KEY_INFO *PKCS8_decrypt(X509_SIG *pkcs8, const char *pass,
                                     int pass_len_in) {
    size_t pass_len;
    if (pass_len_in == -1 && pass != NULL) {
      pass_len = strlen(pass);
    } else {
      pass_len = (size_t)pass_len_in;
    }
  
    PKCS8_PRIV_KEY_INFO *ret = NULL;
    EVP_PKEY *pkey = NULL;
    uint8_t *in = NULL;
  
    // Convert the legacy ASN.1 object to a byte string.
    int in_len = i2d_X509_SIG(pkcs8, &in);
    if (in_len < 0) {
      goto err;
    }
  
    CBS cbs;
    CBS_init(&cbs, in, in_len);
    pkey = PKCS8_parse_encrypted_private_key(&cbs, pass, pass_len);
    if (pkey == NULL || CBS_len(&cbs) != 0) {
      goto err;
    }
  
    ret = EVP_PKEY2PKCS8(pkey);
  
  err:
    OPENSSL_free(in);
    EVP_PKEY_free(pkey);
    return ret;
  }
  
  X509_SIG *PKCS8_encrypt(int pbe_nid, const EVP_CIPHER *cipher, const char *pass,
                          int pass_len_in, const uint8_t *salt, size_t salt_len,
                          int iterations, PKCS8_PRIV_KEY_INFO *p8inf) {
    size_t pass_len;
    if (pass_len_in == -1 && pass != NULL) {
      pass_len = strlen(pass);
    } else {
      pass_len = (size_t)pass_len_in;
    }
  
    // Parse out the private key.
    EVP_PKEY *pkey = EVP_PKCS82PKEY(p8inf);
    if (pkey == NULL) {
      return NULL;
    }
  
    X509_SIG *ret = NULL;
    uint8_t *der = NULL;
    size_t der_len;
    CBB cbb;
    if (!CBB_init(&cbb, 128) ||
        !PKCS8_marshal_encrypted_private_key(&cbb, pbe_nid, cipher, pass,
                                             pass_len, salt, salt_len, iterations,
                                             pkey) ||
        !CBB_finish(&cbb, &der, &der_len)) {
      CBB_cleanup(&cbb);
      goto err;
    }
  
    // Convert back to legacy ASN.1 objects.
    const uint8_t *ptr = der;
    ret = d2i_X509_SIG(NULL, &ptr, der_len);
    if (ret == NULL || ptr != der + der_len) {
      OPENSSL_PUT_ERROR(PKCS8, ERR_R_INTERNAL_ERROR);
      X509_SIG_free(ret);
      ret = NULL;
    }
  
  err:
    OPENSSL_free(der);
    EVP_PKEY_free(pkey);
    return ret;
  }
  
  struct pkcs12_context {
    EVP_PKEY **out_key;
    STACK_OF(X509) *out_certs;
    const char *password;
    size_t password_len;
  };
  
  // PKCS12_handle_sequence parses a BER-encoded SEQUENCE of elements in a PKCS#12
  // structure.
  static int PKCS12_handle_sequence(
      CBS *sequence, struct pkcs12_context *ctx,
      int (*handle_element)(CBS *cbs, struct pkcs12_context *ctx)) {
    uint8_t *storage = NULL;
    CBS in;
    int ret = 0;
  
    // Although a BER->DER conversion is done at the beginning of |PKCS12_parse|,
    // the ASN.1 data gets wrapped in OCTETSTRINGs and/or encrypted and the
    // conversion cannot see through those wrappings. So each time we step
    // through one we need to convert to DER again.
    if (!CBS_asn1_ber_to_der(sequence, &in, &storage)) {
      OPENSSL_PUT_ERROR(PKCS8, PKCS8_R_BAD_PKCS12_DATA);
      return 0;
    }
  
    CBS child;
    if (!CBS_get_asn1(&in, &child, CBS_ASN1_SEQUENCE) ||
        CBS_len(&in) != 0) {
      OPENSSL_PUT_ERROR(PKCS8, PKCS8_R_BAD_PKCS12_DATA);
      goto err;
    }
  
    while (CBS_len(&child) > 0) {
      CBS element;
      if (!CBS_get_asn1(&child, &element, CBS_ASN1_SEQUENCE)) {
        OPENSSL_PUT_ERROR(PKCS8, PKCS8_R_BAD_PKCS12_DATA);
        goto err;
      }
  
      if (!handle_element(&element, ctx)) {
        goto err;
      }
    }
  
    ret = 1;
  
  err:
    OPENSSL_free(storage);
    return ret;
  }
  
  // 1.2.840.113549.1.12.10.1.1
  static const uint8_t kKeyBag[] = {0x2a, 0x86, 0x48, 0x86, 0xf7, 0x0d,
                                    0x01, 0x0c, 0x0a, 0x01, 0x01};
  
  // 1.2.840.113549.1.12.10.1.2
  static const uint8_t kPKCS8ShroudedKeyBag[] = {
      0x2a, 0x86, 0x48, 0x86, 0xf7, 0x0d, 0x01, 0x0c, 0x0a, 0x01, 0x02};
  
  // 1.2.840.113549.1.12.10.1.3
  static const uint8_t kCertBag[] = {0x2a, 0x86, 0x48, 0x86, 0xf7, 0x0d,
                                     0x01, 0x0c, 0x0a, 0x01, 0x03};
  
  // 1.2.840.113549.1.9.20
  static const uint8_t kFriendlyName[] = {0x2a, 0x86, 0x48, 0x86, 0xf7,
                                          0x0d, 0x01, 0x09, 0x14};
  
  // 1.2.840.113549.1.9.21
  static const uint8_t kLocalKeyID[] = {0x2a, 0x86, 0x48, 0x86, 0xf7,
                                        0x0d, 0x01, 0x09, 0x15};
  
  // 1.2.840.113549.1.9.22.1
  static const uint8_t kX509Certificate[] = {0x2a, 0x86, 0x48, 0x86, 0xf7,
                                             0x0d, 0x01, 0x09, 0x16, 0x01};
  
  // parse_bag_attributes parses the bagAttributes field of a SafeBag structure.
  // It sets |*out_friendly_name| to a newly-allocated copy of the friendly name,
  // encoded as a UTF-8 string, or NULL if there is none. It returns one on
  // success and zero on error.
  static int parse_bag_attributes(CBS *attrs, uint8_t **out_friendly_name,
                                  size_t *out_friendly_name_len) {
    *out_friendly_name = NULL;
    *out_friendly_name_len = 0;
  
    // See https://tools.ietf.org/html/rfc7292#section-4.2.
    while (CBS_len(attrs) != 0) {
      CBS attr, oid, values;
      if (!CBS_get_asn1(attrs, &attr, CBS_ASN1_SEQUENCE) ||
          !CBS_get_asn1(&attr, &oid, CBS_ASN1_OBJECT) ||
          !CBS_get_asn1(&attr, &values, CBS_ASN1_SET) ||
          CBS_len(&attr) != 0) {
        OPENSSL_PUT_ERROR(PKCS8, PKCS8_R_BAD_PKCS12_DATA);
        goto err;
      }
      if (CBS_mem_equal(&oid, kFriendlyName, sizeof(kFriendlyName))) {
        // See https://tools.ietf.org/html/rfc2985, section 5.5.1.
        CBS value;
        if (*out_friendly_name != NULL ||
            !CBS_get_asn1(&values, &value, CBS_ASN1_BMPSTRING) ||
            CBS_len(&values) != 0 ||
            CBS_len(&value) == 0) {
          OPENSSL_PUT_ERROR(PKCS8, PKCS8_R_BAD_PKCS12_DATA);
          goto err;
        }
        // Convert the friendly name to UTF-8.
        CBB cbb;
        if (!CBB_init(&cbb, CBS_len(&value))) {
          OPENSSL_PUT_ERROR(PKCS8, ERR_R_MALLOC_FAILURE);
          goto err;
        }
        while (CBS_len(&value) != 0) {
          uint32_t c;
          if (!cbs_get_ucs2_be(&value, &c) ||
              !cbb_add_utf8(&cbb, c)) {
            OPENSSL_PUT_ERROR(PKCS8, PKCS8_R_INVALID_CHARACTERS);
            CBB_cleanup(&cbb);
            goto err;
          }
        }
        if (!CBB_finish(&cbb, out_friendly_name, out_friendly_name_len)) {
          OPENSSL_PUT_ERROR(PKCS8, ERR_R_MALLOC_FAILURE);
          CBB_cleanup(&cbb);
          goto err;
        }
      }
    }
  
    return 1;
  
  err:
    OPENSSL_free(*out_friendly_name);
    *out_friendly_name = NULL;
    *out_friendly_name_len = 0;
    return 0;
  }
  
  // PKCS12_handle_safe_bag parses a single SafeBag element in a PKCS#12
  // structure.
  static int PKCS12_handle_safe_bag(CBS *safe_bag, struct pkcs12_context *ctx) {
    CBS bag_id, wrapped_value, bag_attrs;
    if (!CBS_get_asn1(safe_bag, &bag_id, CBS_ASN1_OBJECT) ||
        !CBS_get_asn1(safe_bag, &wrapped_value,
                      CBS_ASN1_CONTEXT_SPECIFIC | CBS_ASN1_CONSTRUCTED | 0)) {
      OPENSSL_PUT_ERROR(PKCS8, PKCS8_R_BAD_PKCS12_DATA);
      return 0;
    }
    if (CBS_len(safe_bag) == 0) {
      CBS_init(&bag_attrs, NULL, 0);
    } else if (!CBS_get_asn1(safe_bag, &bag_attrs, CBS_ASN1_SET) ||
               CBS_len(safe_bag) != 0) {
      OPENSSL_PUT_ERROR(PKCS8, PKCS8_R_BAD_PKCS12_DATA);
      return 0;
    }
  
    const int is_key_bag = CBS_mem_equal(&bag_id, kKeyBag, sizeof(kKeyBag));
    const int is_shrouded_key_bag = CBS_mem_equal(&bag_id, kPKCS8ShroudedKeyBag,
                                                  sizeof(kPKCS8ShroudedKeyBag));
    if (is_key_bag || is_shrouded_key_bag) {
      // See RFC 7292, section 4.2.1 and 4.2.2.
      if (*ctx->out_key) {
        OPENSSL_PUT_ERROR(PKCS8, PKCS8_R_MULTIPLE_PRIVATE_KEYS_IN_PKCS12);
        return 0;
      }
  
      EVP_PKEY *pkey =
          is_key_bag ? EVP_parse_private_key(&wrapped_value)
                     : PKCS8_parse_encrypted_private_key(
                           &wrapped_value, ctx->password, ctx->password_len);
      if (pkey == NULL) {
        return 0;
      }
  
      if (CBS_len(&wrapped_value) != 0) {
        OPENSSL_PUT_ERROR(PKCS8, PKCS8_R_BAD_PKCS12_DATA);
        EVP_PKEY_free(pkey);
        return 0;
      }
  
      *ctx->out_key = pkey;
      return 1;
    }
  
    if (CBS_mem_equal(&bag_id, kCertBag, sizeof(kCertBag))) {
      // See RFC 7292, section 4.2.3.
      CBS cert_bag, cert_type, wrapped_cert, cert;
      if (!CBS_get_asn1(&wrapped_value, &cert_bag, CBS_ASN1_SEQUENCE) ||
          !CBS_get_asn1(&cert_bag, &cert_type, CBS_ASN1_OBJECT) ||
          !CBS_get_asn1(&cert_bag, &wrapped_cert,
                        CBS_ASN1_CONTEXT_SPECIFIC | CBS_ASN1_CONSTRUCTED | 0) ||
          !CBS_get_asn1(&wrapped_cert, &cert, CBS_ASN1_OCTETSTRING)) {
        OPENSSL_PUT_ERROR(PKCS8, PKCS8_R_BAD_PKCS12_DATA);
        return 0;
      }
  
      // Skip unknown certificate types.
      if (!CBS_mem_equal(&cert_type, kX509Certificate,
                         sizeof(kX509Certificate))) {
        return 1;
      }
  
      if (CBS_len(&cert) > LONG_MAX) {
        OPENSSL_PUT_ERROR(PKCS8, PKCS8_R_BAD_PKCS12_DATA);
        return 0;
      }
  
      const uint8_t *inp = CBS_data(&cert);
      X509 *x509 = d2i_X509(NULL, &inp, (long)CBS_len(&cert));
      if (!x509) {
        OPENSSL_PUT_ERROR(PKCS8, PKCS8_R_BAD_PKCS12_DATA);
        return 0;
      }
  
      if (inp != CBS_data(&cert) + CBS_len(&cert)) {
        OPENSSL_PUT_ERROR(PKCS8, PKCS8_R_BAD_PKCS12_DATA);
        X509_free(x509);
        return 0;
      }
  
      uint8_t *friendly_name;
      size_t friendly_name_len;
      if (!parse_bag_attributes(&bag_attrs, &friendly_name, &friendly_name_len)) {
        X509_free(x509);
        return 0;
      }
      int ok = friendly_name_len == 0 ||
               X509_alias_set1(x509, friendly_name, friendly_name_len);
      OPENSSL_free(friendly_name);
      if (!ok ||
          0 == sk_X509_push(ctx->out_certs, x509)) {
        X509_free(x509);
        return 0;
      }
  
      return 1;
    }
  
    // Unknown element type - ignore it.
    return 1;
  }
  
  // 1.2.840.113549.1.7.1
  static const uint8_t kPKCS7Data[] = {0x2a, 0x86, 0x48, 0x86, 0xf7,
                                       0x0d, 0x01, 0x07, 0x01};
  
  // 1.2.840.113549.1.7.6
  static const uint8_t kPKCS7EncryptedData[] = {0x2a, 0x86, 0x48, 0x86, 0xf7,
                                                0x0d, 0x01, 0x07, 0x06};
  
  // PKCS12_handle_content_info parses a single PKCS#7 ContentInfo element in a
  // PKCS#12 structure.
  static int PKCS12_handle_content_info(CBS *content_info,
                                        struct pkcs12_context *ctx) {
    CBS content_type, wrapped_contents, contents;
    int ret = 0;
    uint8_t *storage = NULL;
  
    if (!CBS_get_asn1(content_info, &content_type, CBS_ASN1_OBJECT) ||
        !CBS_get_asn1(content_info, &wrapped_contents,
                          CBS_ASN1_CONTEXT_SPECIFIC | CBS_ASN1_CONSTRUCTED | 0) ||
        CBS_len(content_info) != 0) {
      OPENSSL_PUT_ERROR(PKCS8, PKCS8_R_BAD_PKCS12_DATA);
      goto err;
    }
  
    if (CBS_mem_equal(&content_type, kPKCS7EncryptedData,
                      sizeof(kPKCS7EncryptedData))) {
      // See https://tools.ietf.org/html/rfc2315#section-13.
      //
      // PKCS#7 encrypted data inside a PKCS#12 structure is generally an
      // encrypted certificate bag and it's generally encrypted with 40-bit
      // RC2-CBC.
      CBS version_bytes, eci, contents_type, ai, encrypted_contents;
      uint8_t *out;
      size_t out_len;
  
      if (!CBS_get_asn1(&wrapped_contents, &contents, CBS_ASN1_SEQUENCE) ||
          !CBS_get_asn1(&contents, &version_bytes, CBS_ASN1_INTEGER) ||
          // EncryptedContentInfo, see
          // https://tools.ietf.org/html/rfc2315#section-10.1
          !CBS_get_asn1(&contents, &eci, CBS_ASN1_SEQUENCE) ||
          !CBS_get_asn1(&eci, &contents_type, CBS_ASN1_OBJECT) ||
          // AlgorithmIdentifier, see
          // https://tools.ietf.org/html/rfc5280#section-4.1.1.2
          !CBS_get_asn1(&eci, &ai, CBS_ASN1_SEQUENCE) ||
          !CBS_get_asn1_implicit_string(
              &eci, &encrypted_contents, &storage,
              CBS_ASN1_CONTEXT_SPECIFIC | 0, CBS_ASN1_OCTETSTRING)) {
        OPENSSL_PUT_ERROR(PKCS8, PKCS8_R_BAD_PKCS12_DATA);
        goto err;
      }
  
      if (!CBS_mem_equal(&contents_type, kPKCS7Data, sizeof(kPKCS7Data))) {
        OPENSSL_PUT_ERROR(PKCS8, PKCS8_R_BAD_PKCS12_DATA);
        goto err;
      }
  
      if (!pkcs8_pbe_decrypt(&out, &out_len, &ai, ctx->password,
                             ctx->password_len, CBS_data(&encrypted_contents),
                             CBS_len(&encrypted_contents))) {
        goto err;
      }
  
      CBS safe_contents;
      CBS_init(&safe_contents, out, out_len);
      ret = PKCS12_handle_sequence(&safe_contents, ctx, PKCS12_handle_safe_bag);
      OPENSSL_free(out);
    } else if (CBS_mem_equal(&content_type, kPKCS7Data, sizeof(kPKCS7Data))) {
      CBS octet_string_contents;
  
      if (!CBS_get_asn1(&wrapped_contents, &octet_string_contents,
                        CBS_ASN1_OCTETSTRING)) {
        OPENSSL_PUT_ERROR(PKCS8, PKCS8_R_BAD_PKCS12_DATA);
        goto err;
      }
  
      ret = PKCS12_handle_sequence(&octet_string_contents, ctx,
                                   PKCS12_handle_safe_bag);
    } else {
      // Unknown element type - ignore it.
      ret = 1;
    }
  
  err:
    OPENSSL_free(storage);
    return ret;
  }
  
  static int pkcs12_check_mac(int *out_mac_ok, const char *password,
                              size_t password_len, const CBS *salt,
                              unsigned iterations, const EVP_MD *md,
                              const CBS *authsafes, const CBS *expected_mac) {
    int ret = 0;
    uint8_t hmac_key[EVP_MAX_MD_SIZE];
    if (!pkcs12_key_gen(password, password_len, CBS_data(salt), CBS_len(salt),
                        PKCS12_MAC_ID, iterations, EVP_MD_size(md), hmac_key,
                        md)) {
      goto err;
    }
  
    uint8_t hmac[EVP_MAX_MD_SIZE];
    unsigned hmac_len;
    if (NULL == HMAC(md, hmac_key, EVP_MD_size(md), CBS_data(authsafes),
                     CBS_len(authsafes), hmac, &hmac_len)) {
      goto err;
    }
  
    *out_mac_ok = CBS_mem_equal(expected_mac, hmac, hmac_len);
  #if defined(BORINGSSL_UNSAFE_FUZZER_MODE)
    *out_mac_ok = 1;
  #endif
    ret = 1;
  
  err:
    OPENSSL_cleanse(hmac_key, sizeof(hmac_key));
    return ret;
  }
  
  
  int PKCS12_get_key_and_certs(EVP_PKEY **out_key, STACK_OF(X509) *out_certs,
                               CBS *ber_in, const char *password) {
    uint8_t *storage = NULL;
    CBS in, pfx, mac_data, authsafe, content_type, wrapped_authsafes, authsafes;
    uint64_t version;
    int ret = 0;
    struct pkcs12_context ctx;
    const size_t original_out_certs_len = sk_X509_num(out_certs);
  
    // The input may be in BER format.
    if (!CBS_asn1_ber_to_der(ber_in, &in, &storage)) {
      OPENSSL_PUT_ERROR(PKCS8, PKCS8_R_BAD_PKCS12_DATA);
      return 0;
    }
  
    *out_key = NULL;
    OPENSSL_memset(&ctx, 0, sizeof(ctx));
  
    // See ftp://ftp.rsasecurity.com/pub/pkcs/pkcs-12/pkcs-12v1.pdf, section
    // four.
    if (!CBS_get_asn1(&in, &pfx, CBS_ASN1_SEQUENCE) ||
        CBS_len(&in) != 0 ||
        !CBS_get_asn1_uint64(&pfx, &version)) {
      OPENSSL_PUT_ERROR(PKCS8, PKCS8_R_BAD_PKCS12_DATA);
      goto err;
    }
  
    if (version < 3) {
      OPENSSL_PUT_ERROR(PKCS8, PKCS8_R_BAD_PKCS12_VERSION);
      goto err;
    }
  
    if (!CBS_get_asn1(&pfx, &authsafe, CBS_ASN1_SEQUENCE)) {
      OPENSSL_PUT_ERROR(PKCS8, PKCS8_R_BAD_PKCS12_DATA);
      goto err;
    }
  
    if (CBS_len(&pfx) == 0) {
      OPENSSL_PUT_ERROR(PKCS8, PKCS8_R_MISSING_MAC);
      goto err;
    }
  
    if (!CBS_get_asn1(&pfx, &mac_data, CBS_ASN1_SEQUENCE)) {
      OPENSSL_PUT_ERROR(PKCS8, PKCS8_R_BAD_PKCS12_DATA);
      goto err;
    }
  
    // authsafe is a PKCS#7 ContentInfo. See
    // https://tools.ietf.org/html/rfc2315#section-7.
    if (!CBS_get_asn1(&authsafe, &content_type, CBS_ASN1_OBJECT) ||
        !CBS_get_asn1(&authsafe, &wrapped_authsafes,
                          CBS_ASN1_CONTEXT_SPECIFIC | CBS_ASN1_CONSTRUCTED | 0)) {
      OPENSSL_PUT_ERROR(PKCS8, PKCS8_R_BAD_PKCS12_DATA);
      goto err;
    }
  
    // The content type can either be data or signedData. The latter indicates
    // that it's signed by a public key, which isn't supported.
    if (!CBS_mem_equal(&content_type, kPKCS7Data, sizeof(kPKCS7Data))) {
      OPENSSL_PUT_ERROR(PKCS8, PKCS8_R_PKCS12_PUBLIC_KEY_INTEGRITY_NOT_SUPPORTED);
      goto err;
    }
  
    if (!CBS_get_asn1(&wrapped_authsafes, &authsafes, CBS_ASN1_OCTETSTRING)) {
      OPENSSL_PUT_ERROR(PKCS8, PKCS8_R_BAD_PKCS12_DATA);
      goto err;
    }
  
    ctx.out_key = out_key;
    ctx.out_certs = out_certs;
    ctx.password = password;
    ctx.password_len = password != NULL ? strlen(password) : 0;
  
    // Verify the MAC.
    {
      CBS mac, salt, expected_mac;
      if (!CBS_get_asn1(&mac_data, &mac, CBS_ASN1_SEQUENCE)) {
        OPENSSL_PUT_ERROR(PKCS8, PKCS8_R_BAD_PKCS12_DATA);
        goto err;
      }
  
      const EVP_MD *md = EVP_parse_digest_algorithm(&mac);
      if (md == NULL) {
        goto err;
      }
  
      if (!CBS_get_asn1(&mac, &expected_mac, CBS_ASN1_OCTETSTRING) ||
          !CBS_get_asn1(&mac_data, &salt, CBS_ASN1_OCTETSTRING)) {
        OPENSSL_PUT_ERROR(PKCS8, PKCS8_R_BAD_PKCS12_DATA);
        goto err;
      }
  
      // The iteration count is optional and the default is one.
      uint64_t iterations = 1;
      if (CBS_len(&mac_data) > 0) {
        if (!CBS_get_asn1_uint64(&mac_data, &iterations) ||
            !pkcs12_iterations_acceptable(iterations)) {
          OPENSSL_PUT_ERROR(PKCS8, PKCS8_R_BAD_PKCS12_DATA);
          goto err;
        }
      }
  
      int mac_ok;
      if (!pkcs12_check_mac(&mac_ok, ctx.password, ctx.password_len, &salt,
                            iterations, md, &authsafes, &expected_mac)) {
        goto err;
      }
      if (!mac_ok && ctx.password_len == 0) {
        // PKCS#12 encodes passwords as NUL-terminated UCS-2, so the empty
        // password is encoded as {0, 0}. Some implementations use the empty byte
        // array for "no password". OpenSSL considers a non-NULL password as {0,
        // 0} and a NULL password as {}. It then, in high-level PKCS#12 parsing
        // code, tries both options. We match this behavior.
        ctx.password = ctx.password != NULL ? NULL : "";
        if (!pkcs12_check_mac(&mac_ok, ctx.password, ctx.password_len, &salt,
                              iterations, md, &authsafes, &expected_mac)) {
          goto err;
        }
      }
      if (!mac_ok) {
        OPENSSL_PUT_ERROR(PKCS8, PKCS8_R_INCORRECT_PASSWORD);
        goto err;
      }
    }
  
    // authsafes contains a series of PKCS#7 ContentInfos.
    if (!PKCS12_handle_sequence(&authsafes, &ctx, PKCS12_handle_content_info)) {
      goto err;
    }
  
    ret = 1;
  
  err:
    OPENSSL_free(storage);
    if (!ret) {
      EVP_PKEY_free(*out_key);
      *out_key = NULL;
      while (sk_X509_num(out_certs) > original_out_certs_len) {
        X509 *x509 = sk_X509_pop(out_certs);
        X509_free(x509);
      }
    }
  
    return ret;
  }
  
  void PKCS12_PBE_add(void) {}
  
  struct pkcs12_st {
    uint8_t *ber_bytes;
    size_t ber_len;
  };
  
  PKCS12 *d2i_PKCS12(PKCS12 **out_p12, const uint8_t **ber_bytes,
                     size_t ber_len) {
    PKCS12 *p12;
  
    p12 = OPENSSL_malloc(sizeof(PKCS12));
    if (!p12) {
      return NULL;
    }
  
    p12->ber_bytes = OPENSSL_malloc(ber_len);
    if (!p12->ber_bytes) {
      OPENSSL_free(p12);
      return NULL;
    }
  
    OPENSSL_memcpy(p12->ber_bytes, *ber_bytes, ber_len);
    p12->ber_len = ber_len;
    *ber_bytes += ber_len;
  
    if (out_p12) {
      PKCS12_free(*out_p12);
  
      *out_p12 = p12;
    }
  
    return p12;
  }
  
  PKCS12* d2i_PKCS12_bio(BIO *bio, PKCS12 **out_p12) {
    size_t used = 0;
    BUF_MEM *buf;
    const uint8_t *dummy;
    static const size_t kMaxSize = 256 * 1024;
    PKCS12 *ret = NULL;
  
    buf = BUF_MEM_new();
    if (buf == NULL) {
      return NULL;
    }
    if (BUF_MEM_grow(buf, 8192) == 0) {
      goto out;
    }
  
    for (;;) {
      int n = BIO_read(bio, &buf->data[used], buf->length - used);
      if (n < 0) {
        if (used == 0) {
          goto out;
        }
        // Workaround a bug in node.js. It uses a memory BIO for this in the wrong
        // mode.
        n = 0;
      }
  
      if (n == 0) {
        break;
      }
      used += n;
  
      if (used < buf->length) {
        continue;
      }
  
      if (buf->length > kMaxSize ||
          BUF_MEM_grow(buf, buf->length * 2) == 0) {
        goto out;
      }
    }
  
    dummy = (uint8_t*) buf->data;
    ret = d2i_PKCS12(out_p12, &dummy, used);
  
  out:
    BUF_MEM_free(buf);
    return ret;
  }
  
  PKCS12* d2i_PKCS12_fp(FILE *fp, PKCS12 **out_p12) {
    BIO *bio;
    PKCS12 *ret;
  
    bio = BIO_new_fp(fp, 0 /* don't take ownership */);
    if (!bio) {
      return NULL;
    }
  
    ret = d2i_PKCS12_bio(bio, out_p12);
    BIO_free(bio);
    return ret;
  }
  
  int i2d_PKCS12(const PKCS12 *p12, uint8_t **out) {
    if (p12->ber_len > INT_MAX) {
      OPENSSL_PUT_ERROR(PKCS8, ERR_R_OVERFLOW);
      return -1;
    }
  
    if (out == NULL) {
      return (int)p12->ber_len;
    }
  
    if (*out == NULL) {
      *out = OPENSSL_malloc(p12->ber_len);
      if (*out == NULL) {
        OPENSSL_PUT_ERROR(PKCS8, ERR_R_MALLOC_FAILURE);
        return -1;
      }
      OPENSSL_memcpy(*out, p12->ber_bytes, p12->ber_len);
    } else {
      OPENSSL_memcpy(*out, p12->ber_bytes, p12->ber_len);
      *out += p12->ber_len;
    }
    return (int)p12->ber_len;
  }
  
  int i2d_PKCS12_bio(BIO *bio, const PKCS12 *p12) {
    return BIO_write_all(bio, p12->ber_bytes, p12->ber_len);
  }
  
  int i2d_PKCS12_fp(FILE *fp, const PKCS12 *p12) {
    BIO *bio = BIO_new_fp(fp, 0 /* don't take ownership */);
    if (bio == NULL) {
      return 0;
    }
  
    int ret = i2d_PKCS12_bio(bio, p12);
    BIO_free(bio);
    return ret;
  }
  
  int PKCS12_parse(const PKCS12 *p12, const char *password, EVP_PKEY **out_pkey,
                   X509 **out_cert, STACK_OF(X509) **out_ca_certs) {
    CBS ber_bytes;
    STACK_OF(X509) *ca_certs = NULL;
    char ca_certs_alloced = 0;
  
    if (out_ca_certs != NULL && *out_ca_certs != NULL) {
      ca_certs = *out_ca_certs;
    }
  
    if (!ca_certs) {
      ca_certs = sk_X509_new_null();
      if (ca_certs == NULL) {
        OPENSSL_PUT_ERROR(PKCS8, ERR_R_MALLOC_FAILURE);
        return 0;
      }
      ca_certs_alloced = 1;
    }
  
    CBS_init(&ber_bytes, p12->ber_bytes, p12->ber_len);
    if (!PKCS12_get_key_and_certs(out_pkey, ca_certs, &ber_bytes, password)) {
      if (ca_certs_alloced) {
        sk_X509_free(ca_certs);
      }
      return 0;
    }
  
    // OpenSSL selects the last certificate which matches the private key as
    // |out_cert|.
    *out_cert = NULL;
    size_t num_certs = sk_X509_num(ca_certs);
    if (*out_pkey != NULL && num_certs > 0) {
      for (size_t i = num_certs - 1; i < num_certs; i--) {
        X509 *cert = sk_X509_value(ca_certs, i);
        if (X509_check_private_key(cert, *out_pkey)) {
          *out_cert = cert;
          sk_X509_delete(ca_certs, i);
          break;
        }
        ERR_clear_error();
      }
    }
  
    if (out_ca_certs) {
      *out_ca_certs = ca_certs;
    } else {
      sk_X509_pop_free(ca_certs, X509_free);
    }
  
    return 1;
  }
  
  int PKCS12_verify_mac(const PKCS12 *p12, const char *password,
                        int password_len) {
    if (password == NULL) {
      if (password_len != 0) {
        return 0;
      }
    } else if (password_len != -1 &&
               (password[password_len] != 0 ||
                OPENSSL_memchr(password, 0, password_len) != NULL)) {
      return 0;
    }
  
    EVP_PKEY *pkey = NULL;
    X509 *cert = NULL;
    if (!PKCS12_parse(p12, password, &pkey, &cert, NULL)) {
      ERR_clear_error();
      return 0;
    }
  
    EVP_PKEY_free(pkey);
    X509_free(cert);
  
    return 1;
  }
  
  // add_bag_attributes adds the bagAttributes field of a SafeBag structure,
  // containing the specified friendlyName and localKeyId attributes.
  static int add_bag_attributes(CBB *bag, const char *name, const uint8_t *key_id,
                                size_t key_id_len) {
    if (name == NULL && key_id_len == 0) {
      return 1;  // Omit the OPTIONAL SET.
    }
    // See https://tools.ietf.org/html/rfc7292#section-4.2.
    CBB attrs, attr, oid, values, value;
    if (!CBB_add_asn1(bag, &attrs, CBS_ASN1_SET)) {
      return 0;
    }
    if (name != NULL) {
      // See https://tools.ietf.org/html/rfc2985, section 5.5.1.
      if (!CBB_add_asn1(&attrs, &attr, CBS_ASN1_SEQUENCE) ||
          !CBB_add_asn1(&attr, &oid, CBS_ASN1_OBJECT) ||
          !CBB_add_bytes(&oid, kFriendlyName, sizeof(kFriendlyName)) ||
          !CBB_add_asn1(&attr, &values, CBS_ASN1_SET) ||
          !CBB_add_asn1(&values, &value, CBS_ASN1_BMPSTRING)) {
        return 0;
      }
      // Convert the friendly name to a BMPString.
      CBS name_cbs;
      CBS_init(&name_cbs, (const uint8_t *)name, strlen(name));
      while (CBS_len(&name_cbs) != 0) {
        uint32_t c;
        if (!cbs_get_utf8(&name_cbs, &c) ||
            !cbb_add_ucs2_be(&value, c)) {
          OPENSSL_PUT_ERROR(PKCS8, PKCS8_R_INVALID_CHARACTERS);
          return 0;
        }
      }
    }
    if (key_id_len != 0) {
      // See https://tools.ietf.org/html/rfc2985, section 5.5.2.
      if (!CBB_add_asn1(&attrs, &attr, CBS_ASN1_SEQUENCE) ||
          !CBB_add_asn1(&attr, &oid, CBS_ASN1_OBJECT) ||
          !CBB_add_bytes(&oid, kLocalKeyID, sizeof(kLocalKeyID)) ||
          !CBB_add_asn1(&attr, &values, CBS_ASN1_SET) ||
          !CBB_add_asn1(&values, &value, CBS_ASN1_OCTETSTRING) ||
          !CBB_add_bytes(&value, key_id, key_id_len)) {
        return 0;
      }
    }
    return CBB_flush_asn1_set_of(&attrs) &&
           CBB_flush(bag);
  }
  
  static int add_cert_bag(CBB *cbb, X509 *cert, const char *name,
                          const uint8_t *key_id, size_t key_id_len) {
    CBB bag, bag_oid, bag_contents, cert_bag, cert_type, wrapped_cert, cert_value;
    if (// See https://tools.ietf.org/html/rfc7292#section-4.2.
        !CBB_add_asn1(cbb, &bag, CBS_ASN1_SEQUENCE) ||
        !CBB_add_asn1(&bag, &bag_oid, CBS_ASN1_OBJECT) ||
        !CBB_add_bytes(&bag_oid, kCertBag, sizeof(kCertBag)) ||
        !CBB_add_asn1(&bag, &bag_contents,
                      CBS_ASN1_CONSTRUCTED | CBS_ASN1_CONTEXT_SPECIFIC | 0) ||
        // See https://tools.ietf.org/html/rfc7292#section-4.2.3.
        !CBB_add_asn1(&bag_contents, &cert_bag, CBS_ASN1_SEQUENCE) ||
        !CBB_add_asn1(&cert_bag, &cert_type, CBS_ASN1_OBJECT) ||
        !CBB_add_bytes(&cert_type, kX509Certificate, sizeof(kX509Certificate)) ||
        !CBB_add_asn1(&cert_bag, &wrapped_cert,
                      CBS_ASN1_CONSTRUCTED | CBS_ASN1_CONTEXT_SPECIFIC | 0) ||
        !CBB_add_asn1(&wrapped_cert, &cert_value, CBS_ASN1_OCTETSTRING)) {
      return 0;
    }
    uint8_t *buf;
    int len = i2d_X509(cert, NULL);
    if (len < 0 ||
        !CBB_add_space(&cert_value, &buf, (size_t)len) ||
        i2d_X509(cert, &buf) < 0 ||
        !add_bag_attributes(&bag, name, key_id, key_id_len) ||
        !CBB_flush(cbb)) {
      return 0;
    }
    return 1;
  }
  
  static int add_cert_safe_contents(CBB *cbb, X509 *cert,
                                    const STACK_OF(X509) *chain, const char *name,
                                    const uint8_t *key_id, size_t key_id_len) {
    CBB safe_contents;
    if (!CBB_add_asn1(cbb, &safe_contents, CBS_ASN1_SEQUENCE) ||
        (cert != NULL &&
         !add_cert_bag(&safe_contents, cert, name, key_id, key_id_len))) {
      return 0;
    }
  
    for (size_t i = 0; i < sk_X509_num(chain); i++) {
      // Only the leaf certificate gets attributes.
      if (!add_cert_bag(&safe_contents, sk_X509_value(chain, i), NULL, NULL, 0)) {
        return 0;
      }
    }
  
    return CBB_flush(cbb);
  }
  
  static int add_encrypted_data(CBB *out, int pbe_nid, const char *password,
                                size_t password_len, unsigned iterations,
                                const uint8_t *in, size_t in_len) {
    uint8_t salt[PKCS5_SALT_LEN];
    if (!RAND_bytes(salt, sizeof(salt))) {
      return 0;
    }
  
    int ret = 0;
    EVP_CIPHER_CTX ctx;
    EVP_CIPHER_CTX_init(&ctx);
    CBB content_info, type, wrapper, encrypted_data, encrypted_content_info,
        inner_type, encrypted_content;
    if (// Add the ContentInfo wrapping.
        !CBB_add_asn1(out, &content_info, CBS_ASN1_SEQUENCE) ||
        !CBB_add_asn1(&content_info, &type, CBS_ASN1_OBJECT) ||
        !CBB_add_bytes(&type, kPKCS7EncryptedData, sizeof(kPKCS7EncryptedData)) ||
        !CBB_add_asn1(&content_info, &wrapper,
                      CBS_ASN1_CONSTRUCTED | CBS_ASN1_CONTEXT_SPECIFIC | 0) ||
        // See https://tools.ietf.org/html/rfc2315#section-13.
        !CBB_add_asn1(&wrapper, &encrypted_data, CBS_ASN1_SEQUENCE) ||
        !CBB_add_asn1_uint64(&encrypted_data, 0 /* version */) ||
        // See https://tools.ietf.org/html/rfc2315#section-10.1.
        !CBB_add_asn1(&encrypted_data, &encrypted_content_info,
                      CBS_ASN1_SEQUENCE) ||
        !CBB_add_asn1(&encrypted_content_info, &inner_type, CBS_ASN1_OBJECT) ||
        !CBB_add_bytes(&inner_type, kPKCS7Data, sizeof(kPKCS7Data)) ||
        // Set up encryption and fill in contentEncryptionAlgorithm.
        !pkcs12_pbe_encrypt_init(&encrypted_content_info, &ctx, pbe_nid,
                                 iterations, password, password_len, salt,
                                 sizeof(salt)) ||
        // Note this tag is primitive. It is an implicitly-tagged OCTET_STRING, so
        // it inherits the inner tag's constructed bit.
        !CBB_add_asn1(&encrypted_content_info, &encrypted_content,
                      CBS_ASN1_CONTEXT_SPECIFIC | 0)) {
      goto err;
    }
  
    size_t max_out = in_len + EVP_CIPHER_CTX_block_size(&ctx);
    if (max_out < in_len) {
      OPENSSL_PUT_ERROR(PKCS8, PKCS8_R_TOO_LONG);
      goto err;
    }
  
    uint8_t *ptr;
    int n1, n2;
    if (!CBB_reserve(&encrypted_content, &ptr, max_out) ||
        !EVP_CipherUpdate(&ctx, ptr, &n1, in, in_len) ||
        !EVP_CipherFinal_ex(&ctx, ptr + n1, &n2) ||
        !CBB_did_write(&encrypted_content, n1 + n2) ||
        !CBB_flush(out)) {
      goto err;
    }
  
    ret = 1;
  
  err:
    EVP_CIPHER_CTX_cleanup(&ctx);
    return ret;
  }
  
  PKCS12 *PKCS12_create(const char *password, const char *name,
                        const EVP_PKEY *pkey, X509 *cert,
                        const STACK_OF(X509)* chain, int key_nid, int cert_nid,
                        int iterations, int mac_iterations, int key_type) {
    if (key_nid == 0) {
      key_nid = NID_pbe_WithSHA1And3_Key_TripleDES_CBC;
    }
    if (cert_nid == 0) {
      cert_nid = NID_pbe_WithSHA1And40BitRC2_CBC;
    }
    if (iterations == 0) {
      iterations = PKCS5_DEFAULT_ITERATIONS;
    }
    if (mac_iterations == 0) {
      mac_iterations = 1;
    }
    if (// In OpenSSL, this specifies a non-standard Microsoft key usage extension
        // which we do not currently support.
        key_type != 0 ||
        // In OpenSSL, -1 here means to omit the MAC, which we do not
        // currently support. Omitting it is also invalid for a password-based
        // PKCS#12 file.
        mac_iterations < 0 ||
        // Don't encode empty objects.
        (pkey == NULL && cert == NULL && sk_X509_num(chain) == 0)) {
      OPENSSL_PUT_ERROR(PKCS8, PKCS8_R_UNSUPPORTED_OPTIONS);
      return 0;
    }
  
    // PKCS#12 is a very confusing recursive data format, built out of another
    // recursive data format. Section 5.1 of RFC7292 describes the encoding
    // algorithm, but there is no clear overview. A quick summary:
    //
    // PKCS#7 defines a ContentInfo structure, which is a overgeneralized typed
    // combinator structure for applying cryptography. We care about two types. A
    // data ContentInfo contains an OCTET STRING and is a leaf node of the
    // combinator tree. An encrypted-data ContentInfo contains encryption
    // parameters (key derivation and encryption) and wraps another ContentInfo,
    // usually data.
    //
    // A PKCS#12 file is a PFX structure (section 4), which contains a single data
    // ContentInfo and a MAC over it. This root ContentInfo is the
    // AuthenticatedSafe and its payload is a SEQUENCE of other ContentInfos, so
    // that different parts of the PKCS#12 file can by differently protected.
    //
    // Each ContentInfo in the AuthenticatedSafe, after undoing all the PKCS#7
    // combinators, has SafeContents payload. A SafeContents is a SEQUENCE of
    // SafeBag. SafeBag is PKCS#12's typed structure, with subtypes such as KeyBag
    // and CertBag. Confusingly, there is a SafeContents bag type which itself
    // recursively contains more SafeBags, but we do not implement this. Bags also
    // can have attributes.
    //
    // The grouping of SafeBags into intermediate ContentInfos does not appear to
    // be significant, except that all SafeBags sharing a ContentInfo have the
    // same level of protection. Additionally, while keys may be encrypted by
    // placing a KeyBag in an encrypted-data ContentInfo, PKCS#12 also defines a
    // key-specific encryption container, PKCS8ShroudedKeyBag, which is used
    // instead.
  
    // Note that |password| may be NULL to specify no password, rather than the
    // empty string. They are encoded differently in PKCS#12. (One is the empty
    // byte array and the other is NUL-terminated UCS-2.)
    size_t password_len = password != NULL ? strlen(password) : 0;
  
    uint8_t key_id[EVP_MAX_MD_SIZE];
    unsigned key_id_len = 0;
    if (cert != NULL && pkey != NULL) {
      if (!X509_check_private_key(cert, pkey) ||
          // Matching OpenSSL, use the SHA-1 hash of the certificate as the local
          // key ID. Some PKCS#12 consumers require one to connect the private key
          // and certificate.
          !X509_digest(cert, EVP_sha1(), key_id, &key_id_len)) {
        return 0;
      }
    }
  
    // See https://tools.ietf.org/html/rfc7292#section-4.
    PKCS12 *ret = NULL;
    CBB cbb, pfx, auth_safe, auth_safe_oid, auth_safe_wrapper, auth_safe_data,
        content_infos;
    uint8_t mac_key[EVP_MAX_MD_SIZE];
    if (!CBB_init(&cbb, 0) ||
        !CBB_add_asn1(&cbb, &pfx, CBS_ASN1_SEQUENCE) ||
        !CBB_add_asn1_uint64(&pfx, 3) ||
        // auth_safe is a data ContentInfo.
        !CBB_add_asn1(&pfx, &auth_safe, CBS_ASN1_SEQUENCE) ||
        !CBB_add_asn1(&auth_safe, &auth_safe_oid, CBS_ASN1_OBJECT) ||
        !CBB_add_bytes(&auth_safe_oid, kPKCS7Data, sizeof(kPKCS7Data)) ||
        !CBB_add_asn1(&auth_safe, &auth_safe_wrapper,
                      CBS_ASN1_CONSTRUCTED | CBS_ASN1_CONTEXT_SPECIFIC | 0) ||
        !CBB_add_asn1(&auth_safe_wrapper, &auth_safe_data,
                      CBS_ASN1_OCTETSTRING) ||
        // See https://tools.ietf.org/html/rfc7292#section-4.1. |auth_safe|'s
        // contains a SEQUENCE of ContentInfos.
        !CBB_add_asn1(&auth_safe_data, &content_infos, CBS_ASN1_SEQUENCE)) {
      goto err;
    }
  
    // If there are any certificates, place them in CertBags wrapped in a single
    // encrypted ContentInfo.
    if (cert != NULL || sk_X509_num(chain) > 0) {
      if (cert_nid < 0) {
        // Place the certificates in an unencrypted ContentInfo. This could be
        // more compactly-encoded by reusing the same ContentInfo as the key, but
        // OpenSSL does not do this. We keep them separate for consistency. (Keys,
        // even when encrypted, are always placed in unencrypted ContentInfos.
        // PKCS#12 defines bag-level encryption for keys.)
        CBB content_info, oid, wrapper, data;
        if (!CBB_add_asn1(&content_infos, &content_info, CBS_ASN1_SEQUENCE) ||
            !CBB_add_asn1(&content_info, &oid, CBS_ASN1_OBJECT) ||
            !CBB_add_bytes(&oid, kPKCS7Data, sizeof(kPKCS7Data)) ||
            !CBB_add_asn1(&content_info, &wrapper,
                          CBS_ASN1_CONSTRUCTED | CBS_ASN1_CONTEXT_SPECIFIC | 0) ||
            !CBB_add_asn1(&wrapper, &data, CBS_ASN1_OCTETSTRING) ||
            !add_cert_safe_contents(&data, cert, chain, name, key_id,
                                    key_id_len) ||
            !CBB_flush(&content_infos)) {
          goto err;
        }
      } else {
        CBB plaintext_cbb;
        int ok = CBB_init(&plaintext_cbb, 0) &&
                 add_cert_safe_contents(&plaintext_cbb, cert, chain, name, key_id,
                                        key_id_len) &&
                 add_encrypted_data(
                     &content_infos, cert_nid, password, password_len, iterations,
                     CBB_data(&plaintext_cbb), CBB_len(&plaintext_cbb));
        CBB_cleanup(&plaintext_cbb);
        if (!ok) {
          goto err;
        }
      }
    }
  
    // If there is a key, place it in a single KeyBag or PKCS8ShroudedKeyBag
    // wrapped in an unencrypted ContentInfo. (One could also place it in a KeyBag
    // inside an encrypted ContentInfo, but OpenSSL does not do this and some
    // PKCS#12 consumers do not support KeyBags.)
    if (pkey != NULL) {
      CBB content_info, oid, wrapper, data, safe_contents, bag, bag_oid,
          bag_contents;
      if (// Add another data ContentInfo.
          !CBB_add_asn1(&content_infos, &content_info, CBS_ASN1_SEQUENCE) ||
          !CBB_add_asn1(&content_info, &oid, CBS_ASN1_OBJECT) ||
          !CBB_add_bytes(&oid, kPKCS7Data, sizeof(kPKCS7Data)) ||
          !CBB_add_asn1(&content_info, &wrapper,
                        CBS_ASN1_CONSTRUCTED | CBS_ASN1_CONTEXT_SPECIFIC | 0) ||
          !CBB_add_asn1(&wrapper, &data, CBS_ASN1_OCTETSTRING) ||
          !CBB_add_asn1(&data, &safe_contents, CBS_ASN1_SEQUENCE) ||
          // Add a SafeBag containing a PKCS8ShroudedKeyBag.
          !CBB_add_asn1(&safe_contents, &bag, CBS_ASN1_SEQUENCE) ||
          !CBB_add_asn1(&bag, &bag_oid, CBS_ASN1_OBJECT)) {
        goto err;
      }
      if (key_nid < 0) {
        if (!CBB_add_bytes(&bag_oid, kKeyBag, sizeof(kKeyBag)) ||
            !CBB_add_asn1(&bag, &bag_contents,
                          CBS_ASN1_CONSTRUCTED | CBS_ASN1_CONTEXT_SPECIFIC | 0) ||
            !EVP_marshal_private_key(&bag_contents, pkey)) {
          goto err;
        }
      } else {
        if (!CBB_add_bytes(&bag_oid, kPKCS8ShroudedKeyBag,
                           sizeof(kPKCS8ShroudedKeyBag)) ||
            !CBB_add_asn1(&bag, &bag_contents,
                          CBS_ASN1_CONSTRUCTED | CBS_ASN1_CONTEXT_SPECIFIC | 0) ||
            !PKCS8_marshal_encrypted_private_key(
                &bag_contents, key_nid, NULL, password, password_len,
                NULL /* generate a random salt */,
                0 /* use default salt length */, iterations, pkey)) {
          goto err;
        }
      }
      if (!add_bag_attributes(&bag, name, key_id, key_id_len) ||
          !CBB_flush(&content_infos)) {
        goto err;
      }
    }
  
    // Compute the MAC. Match OpenSSL in using SHA-1 as the hash function. The MAC
    // covers |auth_safe_data|.
    const EVP_MD *mac_md = EVP_sha1();
    uint8_t mac_salt[PKCS5_SALT_LEN];
    uint8_t mac[EVP_MAX_MD_SIZE];
    unsigned mac_len;
    if (!CBB_flush(&auth_safe_data) ||
        !RAND_bytes(mac_salt, sizeof(mac_salt)) ||
        !pkcs12_key_gen(password, password_len, mac_salt, sizeof(mac_salt),
                        PKCS12_MAC_ID, mac_iterations, EVP_MD_size(mac_md),
                        mac_key, mac_md) ||
        !HMAC(mac_md, mac_key, EVP_MD_size(mac_md), CBB_data(&auth_safe_data),
              CBB_len(&auth_safe_data), mac, &mac_len)) {
      goto err;
    }
  
    CBB mac_data, digest_info, mac_cbb, mac_salt_cbb;
    if (!CBB_add_asn1(&pfx, &mac_data, CBS_ASN1_SEQUENCE) ||
        !CBB_add_asn1(&mac_data, &digest_info, CBS_ASN1_SEQUENCE) ||
        !EVP_marshal_digest_algorithm(&digest_info, mac_md) ||
        !CBB_add_asn1(&digest_info, &mac_cbb, CBS_ASN1_OCTETSTRING) ||
        !CBB_add_bytes(&mac_cbb, mac, mac_len) ||
        !CBB_add_asn1(&mac_data, &mac_salt_cbb, CBS_ASN1_OCTETSTRING) ||
        !CBB_add_bytes(&mac_salt_cbb, mac_salt, sizeof(mac_salt)) ||
        // The iteration count has a DEFAULT of 1, but RFC 7292 says "The default
        // is for historical reasons and its use is deprecated." Thus we
        // explicitly encode the iteration count, though it is not valid DER.
        !CBB_add_asn1_uint64(&mac_data, mac_iterations)) {
      goto err;
    }
  
    ret = OPENSSL_malloc(sizeof(PKCS12));
    if (ret == NULL ||
        !CBB_finish(&cbb, &ret->ber_bytes, &ret->ber_len)) {
      OPENSSL_free(ret);
      ret = NULL;
      goto err;
    }
  
  err:
    OPENSSL_cleanse(mac_key, sizeof(mac_key));
    CBB_cleanup(&cbb);
    return ret;
  }
  
  void PKCS12_free(PKCS12 *p12) {
    if (p12 == NULL) {
      return;
    }
    OPENSSL_free(p12->ber_bytes);
    OPENSSL_free(p12);
  }
  