123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221 |
- // Copyright (c) 2012 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.
- // NOTE: based loosely on mozilla's nsDataChannel.cpp
- #include <algorithm>
- #include "net/base/data_url.h"
- #include "base/base64.h"
- #include "base/containers/cxx20_erase.h"
- #include "base/feature_list.h"
- #include "base/features.h"
- #include "base/strings/escape.h"
- #include "base/strings/string_piece.h"
- #include "base/strings/string_split.h"
- #include "base/strings/string_util.h"
- #include "net/base/mime_util.h"
- #include "net/http/http_response_headers.h"
- #include "net/http/http_util.h"
- #include "url/gurl.h"
- namespace net {
- namespace {
- // A data URL is ready for decode if it:
- // - Doesn't need any extra padding.
- // - Does not have any escaped characters.
- // - Does not have any whitespace.
- bool IsDataURLReadyForDecode(base::StringPiece body) {
- return (body.length() % 4) == 0 && base::ranges::find_if(body, [](char c) {
- return c == '%' ||
- base::IsAsciiWhitespace(c);
- }) == std::end(body);
- }
- } // namespace
- bool DataURL::Parse(const GURL& url,
- std::string* mime_type,
- std::string* charset,
- std::string* data) {
- if (!url.is_valid() || !url.has_scheme())
- return false;
- DCHECK(mime_type->empty());
- DCHECK(charset->empty());
- DCHECK(!data || data->empty());
- base::StringPiece content;
- std::string content_string;
- if (base::FeatureList::IsEnabled(base::features::kOptimizeDataUrls)) {
- // Avoid copying the URL content which can be expensive for large URLs.
- content = url.GetContentPiece();
- } else {
- content_string = url.GetContent();
- content = content_string;
- }
- base::StringPiece::const_iterator begin = content.begin();
- base::StringPiece::const_iterator end = content.end();
- base::StringPiece::const_iterator comma = std::find(begin, end, ',');
- if (comma == end)
- return false;
- std::vector<base::StringPiece> meta_data =
- base::SplitStringPiece(base::MakeStringPiece(begin, comma), ";",
- base::TRIM_WHITESPACE, base::SPLIT_WANT_ALL);
- // These are moved to |mime_type| and |charset| on success.
- std::string mime_type_value;
- std::string charset_value;
- auto iter = meta_data.cbegin();
- if (iter != meta_data.cend()) {
- mime_type_value = base::ToLowerASCII(*iter);
- ++iter;
- }
- static constexpr base::StringPiece kBase64Tag("base64");
- static constexpr base::StringPiece kCharsetTag("charset=");
- bool base64_encoded = false;
- for (; iter != meta_data.cend(); ++iter) {
- if (!base64_encoded &&
- base::EqualsCaseInsensitiveASCII(*iter, kBase64Tag)) {
- base64_encoded = true;
- } else if (charset_value.empty() &&
- base::StartsWith(*iter, kCharsetTag,
- base::CompareCase::INSENSITIVE_ASCII)) {
- charset_value = std::string(iter->substr(kCharsetTag.size()));
- // The grammar for charset is not specially defined in RFC2045 and
- // RFC2397. It just needs to be a token.
- if (!HttpUtil::IsToken(charset_value))
- return false;
- }
- }
- if (mime_type_value.empty()) {
- // Fallback to the default if nothing specified in the mediatype part as
- // specified in RFC2045. As specified in RFC2397, we use |charset| even if
- // |mime_type| is empty.
- mime_type_value = "text/plain";
- if (charset_value.empty())
- charset_value = "US-ASCII";
- } else if (!ParseMimeTypeWithoutParameter(mime_type_value, nullptr,
- nullptr)) {
- // Fallback to the default as recommended in RFC2045 when the mediatype
- // value is invalid. For this case, we don't respect |charset| but force it
- // set to "US-ASCII".
- mime_type_value = "text/plain";
- charset_value = "US-ASCII";
- }
- // The caller may not be interested in receiving the data.
- if (data) {
- // Preserve spaces if dealing with text or xml input, same as mozilla:
- // https://bugzilla.mozilla.org/show_bug.cgi?id=138052
- // but strip them otherwise:
- // https://bugzilla.mozilla.org/show_bug.cgi?id=37200
- // (Spaces in a data URL should be escaped, which is handled below, so any
- // spaces now are wrong. People expect to be able to enter them in the URL
- // bar for text, and it can't hurt, so we allow it.)
- //
- // TODO(mmenke): Is removing all spaces reasonable? GURL removes trailing
- // spaces itself, anyways. Should we just trim leading spaces instead?
- // Allowing random intermediary spaces seems unnecessary.
- auto raw_body = base::MakeStringPiece(comma + 1, end);
- // For base64, we may have url-escaped whitespace which is not part
- // of the data, and should be stripped. Otherwise, the escaped whitespace
- // could be part of the payload, so don't strip it.
- if (base64_encoded) {
- // If the data URL is well formed, we can decode it immediately.
- if (base::FeatureList::IsEnabled(base::features::kOptimizeDataUrls) &&
- IsDataURLReadyForDecode(raw_body)) {
- if (!base::Base64Decode(raw_body, data))
- return false;
- } else {
- std::string unescaped_body = base::UnescapeBinaryURLComponent(raw_body);
- // Strip spaces, which aren't allowed in Base64 encoding.
- base::EraseIf(unescaped_body, base::IsAsciiWhitespace<char>);
- size_t length = unescaped_body.length();
- size_t padding_needed = 4 - (length % 4);
- // If the input wasn't padded, then we pad it as necessary until we have
- // a length that is a multiple of 4 as required by our decoder. We don't
- // correct if the input was incorrectly padded. If |padding_needed| ==
- // 3, then the input isn't well formed and decoding will fail with or
- // without padding.
- if ((padding_needed == 1 || padding_needed == 2) &&
- unescaped_body[length - 1] != '=') {
- unescaped_body.resize(length + padding_needed, '=');
- }
- if (!base::Base64Decode(unescaped_body, data))
- return false;
- }
- } else {
- // Strip whitespace for non-text MIME types.
- std::string temp;
- if (!(mime_type_value.compare(0, 5, "text/") == 0 ||
- mime_type_value.find("xml") != std::string::npos)) {
- temp = std::string(raw_body);
- base::EraseIf(temp, base::IsAsciiWhitespace<char>);
- raw_body = temp;
- }
- *data = base::UnescapeBinaryURLComponent(raw_body);
- }
- }
- *mime_type = std::move(mime_type_value);
- *charset = std::move(charset_value);
- return true;
- }
- Error DataURL::BuildResponse(const GURL& url,
- base::StringPiece method,
- std::string* mime_type,
- std::string* charset,
- std::string* data,
- scoped_refptr<HttpResponseHeaders>* headers) {
- DCHECK(data);
- DCHECK(!*headers);
- if (!DataURL::Parse(url, mime_type, charset, data))
- return ERR_INVALID_URL;
- // |mime_type| set by DataURL::Parse() is guaranteed to be in
- // token "/" token
- // form. |charset| can be an empty string.
- DCHECK(!mime_type->empty());
- // "charset" in the Content-Type header is specified explicitly to follow
- // the "token" ABNF in the HTTP spec. When the DataURL::Parse() call is
- // successful, it's guaranteed that the string in |charset| follows the
- // "token" ABNF.
- std::string content_type = *mime_type;
- if (!charset->empty())
- content_type.append(";charset=" + *charset);
- // The terminal double CRLF isn't needed by TryToCreate().
- *headers = HttpResponseHeaders::TryToCreate(
- "HTTP/1.1 200 OK\r\n"
- "Content-Type:" +
- content_type);
- // Above line should always succeed - TryToCreate() only fails when there are
- // nulls in the string, and DataURL::Parse() can't return nulls in anything
- // but the |data| argument.
- DCHECK(*headers);
- if (base::EqualsCaseInsensitiveASCII(method, "HEAD"))
- data->clear();
- return OK;
- }
- } // namespace net
|