blob: e226313b072d7421f97ecd9147b8d15723e93a35 [file] [log] [blame]
// 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.
#include "net/der/parser.h"
#include "base/check.h"
#include "net/der/parse_values.h"
namespace net {
namespace der {
Parser::Parser() : advance_len_(0) {
CBS_init(&cbs_, nullptr, 0);
}
Parser::Parser(const Input& input) : advance_len_(0) {
CBS_init(&cbs_, input.UnsafeData(), input.Length());
}
bool Parser::PeekTagAndValue(Tag* tag, Input* out) {
CBS peeker = cbs_;
CBS tmp_out;
size_t header_len;
unsigned tag_value;
if (!CBS_get_any_asn1_element(&peeker, &tmp_out, &tag_value, &header_len) ||
!CBS_skip(&tmp_out, header_len)) {
return false;
}
advance_len_ = CBS_len(&tmp_out) + header_len;
*tag = tag_value;
*out = Input(CBS_data(&tmp_out), CBS_len(&tmp_out));
return true;
}
bool Parser::Advance() {
if (advance_len_ == 0)
return false;
bool ret = !!CBS_skip(&cbs_, advance_len_);
advance_len_ = 0;
return ret;
}
bool Parser::HasMore() {
return CBS_len(&cbs_) > 0;
}
bool Parser::ReadRawTLV(Input* out) {
CBS tmp_out;
if (!CBS_get_any_asn1_element(&cbs_, &tmp_out, nullptr, nullptr))
return false;
*out = Input(CBS_data(&tmp_out), CBS_len(&tmp_out));
return true;
}
bool Parser::ReadTagAndValue(Tag* tag, Input* out) {
if (!PeekTagAndValue(tag, out))
return false;
CHECK(Advance());
return true;
}
bool Parser::ReadOptionalTag(Tag tag, absl::optional<Input>* out) {
if (!HasMore()) {
*out = absl::nullopt;
return true;
}
Tag actual_tag;
Input value;
if (!PeekTagAndValue(&actual_tag, &value)) {
return false;
}
if (actual_tag == tag) {
CHECK(Advance());
*out = value;
} else {
advance_len_ = 0;
*out = absl::nullopt;
}
return true;
}
bool Parser::ReadOptionalTag(Tag tag, Input* out, bool* present) {
absl::optional<Input> tmp_out;
if (!ReadOptionalTag(tag, &tmp_out))
return false;
*present = tmp_out.has_value();
*out = tmp_out.value_or(der::Input());
return true;
}
bool Parser::SkipOptionalTag(Tag tag, bool* present) {
Input out;
return ReadOptionalTag(tag, &out, present);
}
bool Parser::ReadTag(Tag tag, Input* out) {
Tag actual_tag;
Input value;
if (!PeekTagAndValue(&actual_tag, &value) || actual_tag != tag) {
return false;
}
CHECK(Advance());
*out = value;
return true;
}
bool Parser::SkipTag(Tag tag) {
Input out;
return ReadTag(tag, &out);
}
// Type-specific variants of ReadTag
bool Parser::ReadConstructed(Tag tag, Parser* out) {
if (!IsConstructed(tag))
return false;
Input data;
if (!ReadTag(tag, &data))
return false;
*out = Parser(data);
return true;
}
bool Parser::ReadSequence(Parser* out) {
return ReadConstructed(kSequence, out);
}
bool Parser::ReadUint8(uint8_t* out) {
Input encoded_int;
if (!ReadTag(kInteger, &encoded_int))
return false;
return ParseUint8(encoded_int, out);
}
bool Parser::ReadUint64(uint64_t* out) {
Input encoded_int;
if (!ReadTag(kInteger, &encoded_int))
return false;
return ParseUint64(encoded_int, out);
}
bool Parser::ReadBitString(BitString* bit_string) {
Input value;
if (!ReadTag(kBitString, &value))
return false;
return ParseBitString(value, bit_string);
}
bool Parser::ReadGeneralizedTime(GeneralizedTime* out) {
Input value;
if (!ReadTag(kGeneralizedTime, &value))
return false;
return ParseGeneralizedTime(value, out);
}
} // namespace der
} // namespace net