// Copyright 2015 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.

#ifndef NET_CERT_INTERNAL_NAME_CONSTRAINTS_H_
#define NET_CERT_INTERNAL_NAME_CONSTRAINTS_H_

#include <stdint.h>

#include <vector>

#include "base/compiler_specific.h"
#include "base/memory/scoped_ptr.h"
#include "net/base/ip_address_number.h"

namespace net {

namespace der {
class Input;
}  // namespace der

// Bitfield values for the GeneralName types defined in RFC 5280. The ordering
// and exact values are not important, but match the order from the RFC for
// convenience.
enum GeneralNameTypes {
  GENERAL_NAME_NONE = 0,
  GENERAL_NAME_OTHER_NAME = 1 << 0,
  GENERAL_NAME_RFC822_NAME = 1 << 1,
  GENERAL_NAME_DNS_NAME = 1 << 2,
  GENERAL_NAME_X400_ADDRESS = 1 << 3,
  GENERAL_NAME_DIRECTORY_NAME = 1 << 4,
  GENERAL_NAME_EDI_PARTY_NAME = 1 << 5,
  GENERAL_NAME_UNIFORM_RESOURCE_IDENTIFIER = 1 << 6,
  GENERAL_NAME_IP_ADDRESS = 1 << 7,
  GENERAL_NAME_REGISTERED_ID = 1 << 8,
};

// Parses a NameConstraints extension value and allows testing whether names are
// allowed under those constraints as defined by RFC 5280 section 4.2.1.10.
class NET_EXPORT NameConstraints {
 public:
  // Represents a GeneralNames structure. When processing GeneralNames, it is
  // often necessary to know which types of names were present, and to check
  // all the names of a certain type. Therefore, a bitfield of all the name
  // types is kept, and the names are split into members for each type. Only
  // name types that are handled by this code are stored (though all types are
  // recorded in the bitfield.)
  // TODO(mattm): This may need to be split out into a public class, since
  // GeneralNames is used other places in a certificate also...
  struct GeneralNames {
    GeneralNames();
    ~GeneralNames();

    // ASCII hostnames.
    std::vector<std::string> dns_names;

    // DER-encoded Name values (not including the Sequence tag).
    std::vector<std::vector<uint8_t>> directory_names;

    // iPAddresses as sequences of octets in network byte order. This will be
    // populated if the GeneralNames represents a Subject Alternative Name.
    std::vector<std::vector<uint8_t>> ip_addresses;

    // iPAddress ranges, as <IP, prefix length> pairs. This will be populated
    // if the GeneralNames represents a Name Constraints.
    std::vector<std::pair<std::vector<uint8_t>, unsigned>> ip_address_ranges;

    // Which name types were present, as a bitfield of GeneralNameTypes.
    // Includes both the supported and unsupported types (although unsupported
    // ones may not be recorded depending on the context, like non-critical name
    // constraints.)
    int present_name_types = GENERAL_NAME_NONE;
  };

  ~NameConstraints();

  // Parses a DER-encoded NameConstraints extension and initializes this object.
  // |extension_value| should be the extnValue from the extension (not including
  // the OCTET STRING tag). |is_critical| should be true if the extension was
  // marked critical. Returns nullptr if parsing the the extension failed.
  // The object lifetime is not bound to the lifetime of |extension_value| data.
  static scoped_ptr<NameConstraints> CreateFromDer(
      const der::Input& extension_value,
      bool is_critical);

  // Tests if a certificate is allowed by the name constraints.
  // |subject_rdn_sequence| should be the DER-encoded value of the subject's
  // RDNSequence (not including Sequence tag), and may be an empty ASN.1
  // sequence. |subject_alt_name_extnvalue_tlv| should be the extnValue of the
  // subjectAltName extension (including the OCTET STRING tag & length), or
  // empty if the cert did not have a subjectAltName extension.
  // Note that this method does not check hostname or IP address in commonName,
  // which is deprecated (crbug.com/308330).
  bool IsPermittedCert(const der::Input& subject_rdn_sequence,
                       const der::Input& subject_alt_name_extnvalue_tlv) const;

  // Returns true if the ASCII hostname |name| is permitted.
  // |name| may be a wildcard hostname (starts with "*."). Eg, "*.bar.com"
  // would not be permitted if "bar.com" is permitted and "foo.bar.com" is
  // excluded, while "*.baz.com" would only be permitted if "baz.com" is
  // permitted.
  bool IsPermittedDNSName(const std::string& name) const;

  // Returns true if the directoryName |name_rdn_sequence| is permitted.
  // |name_rdn_sequence| should be the DER-encoded RDNSequence value (not
  // including the Sequence tag.)
  bool IsPermittedDirectoryName(const der::Input& name_rdn_sequence) const;

  // Returns true if the iPAddress |ip| is permitted.
  bool IsPermittedIP(const IPAddressNumber& ip) const;

  // Returns a bitfield of GeneralNameTypes of all the types constrained by this
  // NameConstraints. Name types that aren't supported will only be present if
  // the name constraint they appeared in was marked critical.
  //
  // RFC 5280 section 4.2.1.10 says:
  // Applications conforming to this profile MUST be able to process name
  // constraints that are imposed on the directoryName name form and SHOULD be
  // able to process name constraints that are imposed on the rfc822Name,
  // uniformResourceIdentifier, dNSName, and iPAddress name forms.
  // If a name constraints extension that is marked as critical
  // imposes constraints on a particular name form, and an instance of
  // that name form appears in the subject field or subjectAltName
  // extension of a subsequent certificate, then the application MUST
  // either process the constraint or reject the certificate.
  int ConstrainedNameTypes() const;

 private:
  bool Parse(const der::Input& extension_value,
             bool is_critical) WARN_UNUSED_RESULT;

  GeneralNames permitted_subtrees_;
  GeneralNames excluded_subtrees_;
};

}  // namespace net

#endif  // NET_CERT_INTERNAL_NAME_CONSTRAINTS_H_
