blob: f9edb3fc6ab1248908b9c42d5ed682dc455588d8 [file] [log] [blame]
// Copyright (c) 2010 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/pem_tokenizer.h"
#include "base/base64.h"
#include "base/strings/string_util.h"
#include "base/strings/stringprintf.h"
namespace {
const char kPEMSearchBlock[] = "-----BEGIN ";
const char kPEMBeginBlock[] = "-----BEGIN %s-----";
const char kPEMEndBlock[] = "-----END %s-----";
} // namespace
namespace net {
using base::StringPiece;
struct PEMTokenizer::PEMType {
std::string type;
std::string header;
std::string footer;
const StringPiece& str,
const std::vector<std::string>& allowed_block_types) {
Init(str, allowed_block_types);
PEMTokenizer::~PEMTokenizer() = default;
bool PEMTokenizer::GetNext() {
while (pos_ != StringPiece::npos) {
// Scan for the beginning of the next PEM encoded block.
pos_ = str_.find(kPEMSearchBlock, pos_);
if (pos_ == StringPiece::npos)
return false; // No more PEM blocks
std::vector<PEMType>::const_iterator it;
// Check to see if it is of an acceptable block type.
for (it = block_types_.begin(); it != block_types_.end(); ++it) {
if (!str_.substr(pos_).starts_with(it->header))
// Look for a footer matching the header. If none is found, then all
// data following this point is invalid and should not be parsed.
StringPiece::size_type footer_pos = str_.find(it->footer, pos_);
if (footer_pos == StringPiece::npos) {
pos_ = StringPiece::npos;
return false;
// Chop off the header and footer and parse the data in between.
StringPiece::size_type data_begin = pos_ + it->header.size();
pos_ = footer_pos + it->footer.size();
block_type_ = it->type;
StringPiece encoded = str_.substr(data_begin,
footer_pos - data_begin);
if (!base::Base64Decode(base::CollapseWhitespaceASCII(encoded.as_string(),
true), &data_)) {
// The most likely cause for a decode failure is a datatype that
// includes PEM headers, which are not supported.
return true;
// If the block did not match any acceptable type, move past it and
// continue the search. Otherwise, |pos_| has been updated to the most
// appropriate search position to continue searching from and should not
// be adjusted.
if (it == block_types_.end())
pos_ += sizeof(kPEMSearchBlock);
return false;
void PEMTokenizer::Init(
const StringPiece& str,
const std::vector<std::string>& allowed_block_types) {
str_ = str;
pos_ = 0;
// Construct PEM header/footer strings for all the accepted types, to
// reduce parsing later.
for (auto it = allowed_block_types.begin(); it != allowed_block_types.end();
++it) {
PEMType allowed_type;
allowed_type.type = *it;
allowed_type.header = base::StringPrintf(kPEMBeginBlock, it->c_str());
allowed_type.footer = base::StringPrintf(kPEMEndBlock, it->c_str());
} // namespace net