// Copyright 2016 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "net/cert/internal/parse_name.h"

#include "base/strings/string_number_conversions.h"
#include "base/strings/string_util.h"
#include "base/strings/utf_string_conversion_utils.h"
#include "base/strings/utf_string_conversions.h"
#include "base/sys_byteorder.h"
#include "base/third_party/icu/icu_utf.h"

namespace net {

namespace {

// Converts a BMPString value in Input |in| to UTF-8.
//
// If the conversion is successful, returns true and stores the result in
// |out|. Otherwise it returns false and leaves |out| unmodified.
bool ConvertBmpStringValue(const der::Input& in, std::string* out) {
  if (in.Length() % 2 != 0)
    return false;

  base::string16 in_16bit;
  if (in.Length()) {
    memcpy(base::WriteInto(&in_16bit, in.Length() / 2 + 1), in.UnsafeData(),
           in.Length());
  }
  for (base::char16& c : in_16bit) {
    // BMPString is UCS-2 in big-endian order.
    c = base::NetToHost16(c);

    // BMPString only supports codepoints in the Basic Multilingual Plane;
    // surrogates are not allowed.
    if (CBU_IS_SURROGATE(c))
      return false;
  }
  return base::UTF16ToUTF8(in_16bit.data(), in_16bit.size(), out);
}

// Converts a UniversalString value in Input |in| to UTF-8.
//
// If the conversion is successful, returns true and stores the result in
// |out|. Otherwise it returns false and leaves |out| unmodified.
bool ConvertUniversalStringValue(const der::Input& in, std::string* out) {
  if (in.Length() % 4 != 0)
    return false;

  std::vector<uint32_t> in_32bit(in.Length() / 4);
  if (in.Length())
    memcpy(in_32bit.data(), in.UnsafeData(), in.Length());
  for (const uint32_t c : in_32bit) {
    // UniversalString is UCS-4 in big-endian order.
    uint32_t codepoint = base::NetToHost32(c);
    if (!CBU_IS_UNICODE_CHAR(codepoint))
      return false;

    base::WriteUnicodeCharacter(codepoint, out);
  }
  return true;
}

std::string OidToString(const uint8_t* data, size_t len) {
  std::string out;
  size_t index = 0;
  while (index < len) {
    uint64_t value = 0;
    while ((data[index] & 0x80) == 0x80 && index < len) {
      value = value << 7 | (data[index] & 0x7F);
      index += 1;
    }
    if (index >= len)
      return std::string();
    value = value << 7 | (data[index] & 0x7F);
    index += 1;

    if (out.empty()) {
      uint8_t first = 0;
      if (value < 40) {
        first = 0;
      } else if (value < 80) {
        first = 1;
        value -= 40;
      } else {
        first = 2;
        value -= 80;
      }
      out = base::NumberToString(first);
    }
    out += "." + base::NumberToString(value);
  }

  return out;
}

}  // namespace

der::Input TypeCommonNameOid() {
  // id-at-commonName: 2.5.4.3 (RFC 5280)
  static const uint8_t oid[] = {0x55, 0x04, 0x03};
  return der::Input(oid);
}

der::Input TypeSurnameOid() {
  // id-at-surname: 2.5.4.4 (RFC 5280)
  static const uint8_t oid[] = {0x55, 0x04, 0x04};
  return der::Input(oid);
}

der::Input TypeSerialNumberOid() {
  // id-at-serialNumber: 2.5.4.5 (RFC 5280)
  static const uint8_t oid[] = {0x55, 0x04, 0x05};
  return der::Input(oid);
}

der::Input TypeCountryNameOid() {
  // id-at-countryName: 2.5.4.6 (RFC 5280)
  static const uint8_t oid[] = {0x55, 0x04, 0x06};
  return der::Input(oid);
}

der::Input TypeLocalityNameOid() {
  // id-at-localityName: 2.5.4.7 (RFC 5280)
  static const uint8_t oid[] = {0x55, 0x04, 0x07};
  return der::Input(oid);
}

der::Input TypeStateOrProvinceNameOid() {
  // id-at-stateOrProvinceName: 2.5.4.8 (RFC 5280)
  static const uint8_t oid[] = {0x55, 0x04, 0x08};
  return der::Input(oid);
}

der::Input TypeStreetAddressOid() {
  // street (streetAddress): 2.5.4.9 (RFC 4519)
  static const uint8_t oid[] = {0x55, 0x04, 0x09};
  return der::Input(oid);
}

der::Input TypeOrganizationNameOid() {
  // id-at-organizationName: 2.5.4.10 (RFC 5280)
  static const uint8_t oid[] = {0x55, 0x04, 0x0a};
  return der::Input(oid);
}

der::Input TypeOrganizationUnitNameOid() {
  // id-at-organizationalUnitName: 2.5.4.11 (RFC 5280)
  static const uint8_t oid[] = {0x55, 0x04, 0x0b};
  return der::Input(oid);
}

der::Input TypeTitleOid() {
  // id-at-title: 2.5.4.12 (RFC 5280)
  static const uint8_t oid[] = {0x55, 0x04, 0x0c};
  return der::Input(oid);
}

der::Input TypeNameOid() {
  // id-at-name: 2.5.4.41 (RFC 5280)
  static const uint8_t oid[] = {0x55, 0x04, 0x29};
  return der::Input(oid);
}

der::Input TypeGivenNameOid() {
  // id-at-givenName: 2.5.4.42 (RFC 5280)
  static const uint8_t oid[] = {0x55, 0x04, 0x2a};
  return der::Input(oid);
}

der::Input TypeInitialsOid() {
  // id-at-initials: 2.5.4.43 (RFC 5280)
  static const uint8_t oid[] = {0x55, 0x04, 0x2b};
  return der::Input(oid);
}

der::Input TypeGenerationQualifierOid() {
  // id-at-generationQualifier: 2.5.4.44 (RFC 5280)
  static const uint8_t oid[] = {0x55, 0x04, 0x2c};
  return der::Input(oid);
}

der::Input TypeDomainComponentOid() {
  // dc (domainComponent): 0.9.2342.19200300.100.1.25 (RFC 4519)
  static const uint8_t oid[] = {0x09, 0x92, 0x26, 0x89, 0x93,
                                0xF2, 0x2C, 0x64, 0x01, 0x19};
  return der::Input(oid);
}

bool X509NameAttribute::ValueAsString(std::string* out) const {
  switch (value_tag) {
    case der::kTeletexString: {
      // Convert from Latin-1 to UTF-8.
      size_t utf8_length = value.Length();
      for (size_t i = 0; i < value.Length(); i++) {
        if (value.UnsafeData()[i] > 0x7f)
          utf8_length++;
      }
      out->reserve(utf8_length);
      for (size_t i = 0; i < value.Length(); i++) {
        uint8_t u = value.UnsafeData()[i];
        if (u <= 0x7f) {
          out->push_back(u);
        } else {
          out->push_back(0xc0 | (u >> 6));
          out->push_back(0x80 | (u & 0x3f));
        }
      }
      DCHECK_EQ(utf8_length, out->size());
      return true;
    }
    case der::kIA5String:
      for (char c : value.AsStringPiece()) {
        if (static_cast<uint8_t>(c) > 127)
          return false;
      }
      *out = value.AsString();
      return true;
    case der::kPrintableString:
      for (char c : value.AsStringPiece()) {
        if (!(base::IsAsciiAlpha(c) || c == ' ' || (c >= '\'' && c <= ':') ||
              c == '=' || c == '?')) {
          return false;
        }
      }
      *out = value.AsString();
      return true;
    case der::kUtf8String:
      *out = value.AsString();
      return true;
    case der::kUniversalString:
      return ConvertUniversalStringValue(value, out);
    case der::kBmpString:
      return ConvertBmpStringValue(value, out);
    default:
      return false;
  }
}

bool X509NameAttribute::ValueAsStringWithUnsafeOptions(
    PrintableStringHandling printable_string_handling,
    std::string* out) const {
  if (printable_string_handling == PrintableStringHandling::kAsUTF8Hack &&
      value_tag == der::kPrintableString) {
    *out = value.AsString();
    return true;
  }
  return ValueAsString(out);
}

bool X509NameAttribute::ValueAsStringUnsafe(std::string* out) const {
  switch (value_tag) {
    case der::kIA5String:
    case der::kPrintableString:
    case der::kTeletexString:
    case der::kUtf8String:
      *out = value.AsString();
      return true;
    case der::kUniversalString:
      return ConvertUniversalStringValue(value, out);
    case der::kBmpString:
      return ConvertBmpStringValue(value, out);
    default:
      NOTREACHED();
      return false;
  }
}

bool X509NameAttribute::AsRFC2253String(std::string* out) const {
  std::string type_string;
  std::string value_string;
  // TODO(mattm): Add streetAddress and domainComponent here?
  if (type == TypeCommonNameOid()) {
    type_string = "CN";
  } else if (type == TypeSurnameOid()) {
    type_string = "SN";
  } else if (type == TypeCountryNameOid()) {
    type_string = "C";
  } else if (type == TypeLocalityNameOid()) {
    type_string = "L";
  } else if (type == TypeStateOrProvinceNameOid()) {
    type_string = "ST";
  } else if (type == TypeOrganizationNameOid()) {
    type_string = "O";
  } else if (type == TypeOrganizationUnitNameOid()) {
    type_string = "OU";
  } else if (type == TypeGivenNameOid()) {
    type_string = "GN";
  } else {
    type_string = OidToString(type.UnsafeData(), type.Length());
    if (type_string.empty())
      return false;
    value_string = "#" + base::HexEncode(value.UnsafeData(), value.Length());
  }

  if (value_string.empty()) {
    std::string unescaped;
    if (!ValueAsStringUnsafe(&unescaped))
      return false;

    bool nonprintable = false;
    for (unsigned int i = 0; i < unescaped.length(); ++i) {
      unsigned char c = static_cast<unsigned char>(unescaped[i]);
      if (i == 0 && c == '#') {
        value_string += "\\#";
      } else if (i == 0 && c == ' ') {
        value_string += "\\ ";
      } else if (i == unescaped.length() - 1 && c == ' ') {
        value_string += "\\ ";
      } else if (c == ',' || c == '+' || c == '"' || c == '\\' || c == '<' ||
                 c == '>' || c == ';') {
        value_string += "\\";
        value_string += c;
      } else if (c < 32 || c > 126) {
        nonprintable = true;
        std::string h;
        h += c;
        value_string += "\\" + base::HexEncode(h.data(), h.length());
      } else {
        value_string += c;
      }
    }

    // If we have non-printable characters in a TeletexString, we hex encode
    // since we don't handle Teletex control codes.
    if (nonprintable && value_tag == der::kTeletexString)
      value_string = "#" + base::HexEncode(value.UnsafeData(), value.Length());
  }

  *out = type_string + "=" + value_string;
  return true;
}

bool ReadRdn(der::Parser* parser, RelativeDistinguishedName* out) {
  while (parser->HasMore()) {
    der::Parser attr_type_and_value;
    if (!parser->ReadSequence(&attr_type_and_value))
      return false;
    // Read the attribute type, which must be an OBJECT IDENTIFIER.
    der::Input type;
    if (!attr_type_and_value.ReadTag(der::kOid, &type))
      return false;

    // Read the attribute value.
    der::Tag tag;
    der::Input value;
    if (!attr_type_and_value.ReadTagAndValue(&tag, &value))
      return false;

    // There should be no more elements in the sequence after reading the
    // attribute type and value.
    if (attr_type_and_value.HasMore())
      return false;

    out->push_back(X509NameAttribute(type, tag, value));
  }

  // RFC 5280 section 4.1.2.4
  // RelativeDistinguishedName ::= SET SIZE (1..MAX) OF AttributeTypeAndValue
  return out->size() != 0;
}

bool ParseName(const der::Input& name_tlv, RDNSequence* out) {
  der::Parser name_parser(name_tlv);
  der::Input name_value;
  if (!name_parser.ReadTag(der::kSequence, &name_value))
    return false;
  return ParseNameValue(name_value, out);
}

bool ParseNameValue(const der::Input& name_value, RDNSequence* out) {
  der::Parser rdn_sequence_parser(name_value);
  while (rdn_sequence_parser.HasMore()) {
    der::Parser rdn_parser;
    if (!rdn_sequence_parser.ReadConstructed(der::kSet, &rdn_parser))
      return false;
    RelativeDistinguishedName type_and_values;
    if (!ReadRdn(&rdn_parser, &type_and_values))
      return false;
    out->push_back(type_and_values);
  }

  return true;
}

bool ConvertToRFC2253(const RDNSequence& rdn_sequence, std::string* out) {
  std::string rdns_string;
  size_t size = rdn_sequence.size();
  for (size_t i = 0; i < size; ++i) {
    RelativeDistinguishedName rdn = rdn_sequence[size - i - 1];
    std::string rdn_string;
    for (const auto& atv : rdn) {
      if (!rdn_string.empty())
        rdn_string += "+";
      std::string atv_string;
      if (!atv.AsRFC2253String(&atv_string))
        return false;
      rdn_string += atv_string;
    }
    if (!rdns_string.empty())
      rdns_string += ",";
    rdns_string += rdn_string;
  }

  *out = rdns_string;
  return true;
}

}  // namespace net