Bring the handling of <keygen> and support for the application/x-x509-user-ce...

net/base/pem_tokenizer.cc

+// 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/base/pem_tokenizer.h"
+
+#include "base/base64.h"
+#include "base/string_util.h"
+
+namespace {
+
+const char kPEMSearchBlock[] = "-----BEGIN ";
+const char kPEMBeginBlock[] = "-----BEGIN %s-----";
+const char kPEMEndBlock[] = "-----END %s-----";
+
+}  // namespace
+
+namespace net {
+
+using base::StringPiece;
+
+PEMTokenizer::PEMTokenizer(
+    const StringPiece* str,
+    const std::vector<std::string>& allowed_block_types) {
+  Init(str, allowed_block_types);
+}
+
+bool PEMTokenizer::GetNext() {
+  if (pos_ == StringPiece::npos)
+    return false;  // End of search
+
+  while (pos_ != StringPiece::npos) {
+    pos_ = str_->find(kPEMSearchBlock, pos_);
+    if (pos_ == StringPiece::npos)
+      return false;  // No more PEM blocks
+
+    std::vector<PEMType>::const_iterator it = block_types_.end();
+    // 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))
+        continue;
+
+      StringPiece::size_type footer_pos = str_->find(it->footer, pos_);
+      if (footer_pos == StringPiece::npos) {
+        // A PEM header with no PEM footer has been found. All data
+        // after pos_ is now suspect, and thus will not be parsed.
+        pos_ = StringPiece::npos;
+        return false;
+      }
+
+      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(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.
+        break;
+      }
+
+      // PEM block succesfully decoded into |data_|, and the type has
+      // been stored into |block_type_|
+      return true;
+    }
+
+    // If the block did not match any acceptable type, move past it and
+    // continue the search. If |it| is any other value, then we can be
+    // assured that |pos_| has been updated to the most appropriate search
+    // position to continue searching from.
+    if (it == block_types_.end())
+      pos_ += sizeof(kPEMSearchBlock);
+  }
+
+  return false;
+}
+
+void PEMTokenizer::Init(
+    const StringPiece* str,
+    const std::vector<std::string>& allowed_block_types) {
+  DCHECK(str);
+
+  str_ = str;
+  pos_ = 0;
+
+  // Construct PEM strings for all the accepted types for efficient
+  // comparison.
+  for (std::vector<std::string>::const_iterator it =
+      allowed_block_types.begin(); it != allowed_block_types.end(); ++it) {
+    PEMType allowed_type;
+    allowed_type.type = *it;
+    allowed_type.header = StringPrintf(kPEMBeginBlock, it->c_str());
+    allowed_type.footer = StringPrintf(kPEMEndBlock, it->c_str());
+    block_types_.push_back(allowed_type);
+  }
+}
+
+}  // namespace net