blob: 4ae76481a82ba3d3619a4afce0c30ca9145d0715 [file] [log] [blame]
// Copyright 2015 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "parser.h"
#include "parse_values.h"
BSSL_NAMESPACE_BEGIN
namespace der {
Parser::Parser() { CBS_init(&cbs_, nullptr, 0); }
Parser::Parser(Input input) { CBS_init(&cbs_, input.data(), input.size()); }
bool Parser::PeekTagAndValue(CBS_ASN1_TAG *tag, Input *out) {
CBS peeker = cbs_;
CBS tmp_out;
size_t header_len;
CBS_ASN1_TAG 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(CBS_ASN1_TAG *tag, Input *out) {
if (!PeekTagAndValue(tag, out)) {
return false;
}
BSSL_CHECK(Advance());
return true;
}
bool Parser::ReadOptionalTag(CBS_ASN1_TAG tag, std::optional<Input> *out) {
if (!HasMore()) {
*out = std::nullopt;
return true;
}
CBS_ASN1_TAG actual_tag;
Input value;
if (!PeekTagAndValue(&actual_tag, &value)) {
return false;
}
if (actual_tag == tag) {
BSSL_CHECK(Advance());
*out = value;
} else {
advance_len_ = 0;
*out = std::nullopt;
}
return true;
}
bool Parser::ReadOptionalTag(CBS_ASN1_TAG tag, Input *out, bool *present) {
std::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(CBS_ASN1_TAG tag, bool *present) {
Input out;
return ReadOptionalTag(tag, &out, present);
}
bool Parser::ReadTag(CBS_ASN1_TAG tag, Input *out) {
CBS_ASN1_TAG actual_tag;
Input value;
if (!PeekTagAndValue(&actual_tag, &value) || actual_tag != tag) {
return false;
}
BSSL_CHECK(Advance());
*out = value;
return true;
}
bool Parser::SkipTag(CBS_ASN1_TAG tag) {
Input out;
return ReadTag(tag, &out);
}
// Type-specific variants of ReadTag
bool Parser::ReadConstructed(CBS_ASN1_TAG tag, Parser *out) {
if (!(tag & CBS_ASN1_CONSTRUCTED)) {
return false;
}
Input data;
if (!ReadTag(tag, &data)) {
return false;
}
*out = Parser(data);
return true;
}
bool Parser::ReadSequence(Parser *out) {
return ReadConstructed(CBS_ASN1_SEQUENCE, out);
}
bool Parser::ReadUint8(uint8_t *out) {
Input encoded_int;
if (!ReadTag(CBS_ASN1_INTEGER, &encoded_int)) {
return false;
}
return ParseUint8(encoded_int, out);
}
bool Parser::ReadUint64(uint64_t *out) {
Input encoded_int;
if (!ReadTag(CBS_ASN1_INTEGER, &encoded_int)) {
return false;
}
return ParseUint64(encoded_int, out);
}
std::optional<BitString> Parser::ReadBitString() {
Input value;
if (!ReadTag(CBS_ASN1_BITSTRING, &value)) {
return std::nullopt;
}
return ParseBitString(value);
}
bool Parser::ReadGeneralizedTime(GeneralizedTime *out) {
Input value;
if (!ReadTag(CBS_ASN1_GENERALIZEDTIME, &value)) {
return false;
}
return ParseGeneralizedTime(value, out);
}
} // namespace der
BSSL_NAMESPACE_END