// Copyright 2000-2016 The OpenSSL Project Authors. All Rights Reserved.

//

// Licensed under the Apache License, Version 2.0 (the "License");

// you may not use this file except in compliance with the License.

// You may obtain a copy of the License at

//

//     https://www.apache.org/licenses/LICENSE-2.0

//

// Unless required by applicable law or agreed to in writing, software

// distributed under the License is distributed on an "AS IS" BASIS,

// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

// See the License for the specific language governing permissions and

// limitations under the License.

#include <openssl/asn1.h>

#include <assert.h>

#include <string.h>

#include <openssl/asn1t.h>

#include <openssl/err.h>

#include <openssl/mem.h>

#include <openssl/obj.h>

#include <openssl/pool.h>

#include "../internal.h"

#include "internal.h"

using namespace bssl;

// Utility functions for manipulating fields and offsets

// Add 'offset' to 'addr'

#define offset2ptr(addr, offset) (void *)(((char *)(addr)) + (offset))

// Given an ASN1_ITEM CHOICE type return the selector value

int bssl::asn1_get_choice_selector(ASN1_VALUE **pval, const ASN1_ITEM *it) {

  int *sel =

      reinterpret_cast<int *>(offset2ptr(asn1_load_ptr(pval), it->utype));

  return *sel;

}

// Given an ASN1_ITEM CHOICE type set the selector value, return old value.

int bssl::asn1_set_choice_selector(ASN1_VALUE **pval, int value,

                                   const ASN1_ITEM *it) {

  int *sel, ret;

  sel = reinterpret_cast<int *>(offset2ptr(asn1_load_ptr(pval), it->utype));

  ret = *sel;

  *sel = value;

  return ret;

}

static CRYPTO_refcount_t *asn1_get_references(ASN1_VALUE **pval,

                                              const ASN1_ITEM *it) {

  if (it->itype != ASN1_ITYPE_SEQUENCE) {

    return nullptr;

  }

  const ASN1_AUX *aux = reinterpret_cast<const ASN1_AUX *>(it->funcs);

  if (!aux || !(aux->flags & ASN1_AFLG_REFCOUNT)) {

    return nullptr;

  }

  return reinterpret_cast<CRYPTO_refcount_t *>(

      offset2ptr(asn1_load_ptr(pval), aux->ref_offset));

}

void bssl::asn1_refcount_set_one(ASN1_VALUE **pval, const ASN1_ITEM *it) {

  CRYPTO_refcount_t *references = asn1_get_references(pval, it);

  if (references != nullptr) {

    *references = 1;

  }

}

int bssl::asn1_refcount_dec_and_test_zero(ASN1_VALUE **pval,

                                          const ASN1_ITEM *it) {

  CRYPTO_refcount_t *references = asn1_get_references(pval, it);

  if (references != nullptr) {

    return CRYPTO_refcount_dec_and_test_zero(references);

  }

  return 1;

}

static ASN1_ENCODING *asn1_get_enc_ptr(ASN1_VALUE **pval, const ASN1_ITEM *it) {

  assert(it->itype == ASN1_ITYPE_SEQUENCE);

  const ASN1_AUX *aux;

  if (!pval || !asn1_load_ptr(pval)) {

    return nullptr;

  }

  aux = reinterpret_cast<const ASN1_AUX *>(it->funcs);

  if (!aux || !(aux->flags & ASN1_AFLG_ENCODING)) {

    return nullptr;

  }

  return reinterpret_cast<ASN1_ENCODING *>(

      offset2ptr(asn1_load_ptr(pval), aux->enc_offset));

}

void bssl::asn1_enc_init(ASN1_VALUE **pval, const ASN1_ITEM *it) {

  ASN1_ENCODING *enc = asn1_get_enc_ptr(pval, it);

  if (enc) {

    enc->enc = nullptr;

    enc->len = 0;

  }

}

void bssl::asn1_enc_free(ASN1_VALUE **pval, const ASN1_ITEM *it) {

  ASN1_ENCODING *enc = asn1_get_enc_ptr(pval, it);

  if (enc) {

    asn1_encoding_clear(enc);

  }

}

int bssl::asn1_enc_save(ASN1_VALUE **pval, const uint8_t *in, size_t in_len,

                        const ASN1_ITEM *it) {

  ASN1_ENCODING *enc;

  enc = asn1_get_enc_ptr(pval, it);

  if (!enc) {

    return 1;

  }

  asn1_encoding_clear(enc);

  enc->enc = reinterpret_cast<uint8_t *>(OPENSSL_memdup(in, in_len));

  if (!enc->enc) {

    return 0;

  }

  enc->len = in_len;

  return 1;

}

void bssl::asn1_encoding_clear(ASN1_ENCODING *enc) {

  OPENSSL_free(enc->enc);

  enc->enc = nullptr;

  enc->len = 0;

}

int bssl::asn1_enc_restore(Span<const uint8_t> *out, ASN1_VALUE **pval,

                           const ASN1_ITEM *it) {

  ASN1_ENCODING *enc = asn1_get_enc_ptr(pval, it);

  if (!enc || enc->len == 0) {

    return 0;

  }

  *out = Span(enc->enc, enc->len);

  return 1;

}

// Given an ASN1_TEMPLATE get a pointer to a field

ASN1_VALUE **bssl::asn1_get_field_ptr(ASN1_VALUE **pval,

                                      const ASN1_TEMPLATE *tt) {

  return reinterpret_cast<ASN1_VALUE **>(

      offset2ptr(asn1_load_ptr(pval), tt->offset));

}

// Handle ANY DEFINED BY template, find the selector, look up the relevant

// ASN1_TEMPLATE in the table and return it.

const ASN1_TEMPLATE *bssl::asn1_do_adb(ASN1_VALUE **pval,

                                       const ASN1_TEMPLATE *tt, int nullerr) {

  if (!(tt->flags & ASN1_TFLG_ADB_MASK)) {

    return tt;

  }

  // Else ANY DEFINED BY ... get the table

  const ASN1_ADB *adb = ASN1_ADB_ptr(tt->item);

  // Get the selector field

  ASN1_VALUE **sfld = reinterpret_cast<ASN1_VALUE **>(

      offset2ptr(asn1_load_ptr(pval), adb->offset));

  int selector;

  const ASN1_OBJECT *selector_obj = asn1_load_ptr_as<ASN1_OBJECT>(sfld);

  if (selector_obj == nullptr) {

    if (!adb->null_tt) {

      goto err;

    }

    return adb->null_tt;

  }

  // Convert type to a NID:

  // NB: don't check for NID_undef here because it

  // might be a legitimate value in the table

  assert(tt->flags & ASN1_TFLG_ADB_OID);

  selector = OBJ_obj2nid(asn1_load_ptr_as<ASN1_OBJECT>(sfld));

  // Try to find matching entry in table Maybe should check application types

  // first to allow application override? Might also be useful to have a flag

  // which indicates table is sorted and we can do a binary search. For now

  // stick to a linear search.

  for (int i = 0; i < adb->tblcount; i++) {

    const ASN1_ADB_TABLE *atbl = &adb->tbl[i];

    if (atbl->value == selector) {

      return &atbl->tt;

    }

  }

  // No match, return default type

  if (!adb->default_tt) {

    goto err;

  }

  return adb->default_tt;

err:

  // FIXME: should log the value or OID of unsupported type

  if (nullerr) {

    OPENSSL_PUT_ERROR(ASN1, ASN1_R_UNSUPPORTED_ANY_DEFINED_BY_TYPE);

  }

  return nullptr;

}

CBS_ASN1_TAG bssl::asn1_tag_to_cbs(int aclass, int tag) {

  if ((aclass & ASN1_TFLG_TAG_CLASS) != aclass ||  //

      tag < 0 || static_cast<CBS_ASN1_TAG>(tag) > CBS_ASN1_TAG_NUMBER_MASK ||

      // Universal tag zero is reserved and should never appear in a template.

      // This file treats the zero tag as a sentinel value.

      (aclass == 0 && tag == 0)) {

    OPENSSL_PUT_ERROR(ASN1, ASN1_R_BAD_TEMPLATE);

    return 0;

  }

  return ((static_cast<CBS_ASN1_TAG>(aclass)) << CBS_ASN1_TAG_SHIFT) |

         static_cast<CBS_ASN1_TAG>(tag);

}