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/*
* Copyright (C) 2008 Apple Inc. All Rights Reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
* OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
*/
#include "config.h"
#include "CrossOriginAccessControl.h"
#include "HTTPHeaderNames.h"
#include "HTTPParsers.h"
#include "ResourceRequest.h"
#include "ResourceResponse.h"
#include "SchemeRegistry.h"
#include "SecurityOrigin.h"
#include <mutex>
#include <wtf/NeverDestroyed.h>
#include <wtf/text/AtomicString.h>
#include <wtf/text/StringBuilder.h>
namespace WebCore {
bool isOnAccessControlSimpleRequestMethodWhitelist(const String& method)
{
return method == "GET" || method == "HEAD" || method == "POST";
}
bool isOnAccessControlSimpleRequestHeaderWhitelist(HTTPHeaderName name, const String& value)
{
switch (name) {
case HTTPHeaderName::Accept:
case HTTPHeaderName::AcceptLanguage:
case HTTPHeaderName::ContentLanguage:
case HTTPHeaderName::Origin:
case HTTPHeaderName::Referer:
return true;
case HTTPHeaderName::ContentType: {
// Preflight is required for MIME types that can not be sent via form submission.
String mimeType = extractMIMETypeFromMediaType(value);
return equalIgnoringASCIICase(mimeType, "application/x-www-form-urlencoded")
|| equalIgnoringASCIICase(mimeType, "multipart/form-data")
|| equalIgnoringASCIICase(mimeType, "text/plain");
}
default:
return false;
}
}
bool isSimpleCrossOriginAccessRequest(const String& method, const HTTPHeaderMap& headerMap)
{
if (!isOnAccessControlSimpleRequestMethodWhitelist(method))
return false;
for (const auto& header : headerMap) {
if (!header.keyAsHTTPHeaderName || !isOnAccessControlSimpleRequestHeaderWhitelist(header.keyAsHTTPHeaderName.value(), header.value))
return false;
}
return true;
}
bool isOnAccessControlResponseHeaderWhitelist(const String& name)
{
static std::once_flag onceFlag;
static LazyNeverDestroyed<HTTPHeaderSet> allowedCrossOriginResponseHeaders;
std::call_once(onceFlag, []{
allowedCrossOriginResponseHeaders.construct<std::initializer_list<String>>({
"cache-control",
"content-language",
"content-type",
"expires",
"last-modified",
"pragma"
});
});
return allowedCrossOriginResponseHeaders.get().contains(name);
}
void updateRequestForAccessControl(ResourceRequest& request, SecurityOrigin* securityOrigin, StoredCredentials allowCredentials)
{
request.removeCredentials();
request.setAllowCookies(allowCredentials == AllowStoredCredentials);
request.setHTTPOrigin(securityOrigin->toString());
}
ResourceRequest createAccessControlPreflightRequest(const ResourceRequest& request, SecurityOrigin* securityOrigin)
{
ResourceRequest preflightRequest(request.url());
updateRequestForAccessControl(preflightRequest, securityOrigin, DoNotAllowStoredCredentials);
preflightRequest.setHTTPMethod("OPTIONS");
preflightRequest.setHTTPHeaderField(HTTPHeaderName::AccessControlRequestMethod, request.httpMethod());
preflightRequest.setPriority(request.priority());
const HTTPHeaderMap& requestHeaderFields = request.httpHeaderFields();
if (!requestHeaderFields.isEmpty()) {
StringBuilder headerBuffer;
bool appendComma = false;
for (const auto& headerField : requestHeaderFields) {
if (appendComma)
headerBuffer.appendLiteral(", ");
else
appendComma = true;
headerBuffer.append(headerField.key);
}
preflightRequest.setHTTPHeaderField(HTTPHeaderName::AccessControlRequestHeaders, headerBuffer.toString().convertToASCIILowercase());
}
return preflightRequest;
}
bool isValidCrossOriginRedirectionURL(const URL& redirectURL)
{
return SchemeRegistry::shouldTreatURLSchemeAsCORSEnabled(redirectURL.protocol())
&& redirectURL.user().isEmpty()
&& redirectURL.pass().isEmpty();
}
void cleanRedirectedRequestForAccessControl(ResourceRequest& request)
{
// Remove headers that may have been added by the network layer that cause access control to fail.
request.clearHTTPContentType();
request.clearHTTPReferrer();
request.clearHTTPOrigin();
request.clearHTTPUserAgent();
request.clearHTTPAccept();
request.clearHTTPAcceptEncoding();
}
bool passesAccessControlCheck(const ResourceResponse& response, StoredCredentials includeCredentials, SecurityOrigin* securityOrigin, String& errorDescription)
{
// A wildcard Access-Control-Allow-Origin can not be used if credentials are to be sent,
// even with Access-Control-Allow-Credentials set to true.
const String& accessControlOriginString = response.httpHeaderField(HTTPHeaderName::AccessControlAllowOrigin);
if (accessControlOriginString == "*" && includeCredentials == DoNotAllowStoredCredentials)
return true;
// FIXME: Access-Control-Allow-Origin can contain a list of origins.
if (accessControlOriginString != securityOrigin->toString()) {
if (accessControlOriginString == "*")
errorDescription = "Cannot use wildcard in Access-Control-Allow-Origin when credentials flag is true.";
else
errorDescription = "Origin " + securityOrigin->toString() + " is not allowed by Access-Control-Allow-Origin.";
return false;
}
if (includeCredentials == AllowStoredCredentials) {
const String& accessControlCredentialsString = response.httpHeaderField(HTTPHeaderName::AccessControlAllowCredentials);
if (accessControlCredentialsString != "true") {
errorDescription = "Credentials flag is true, but Access-Control-Allow-Credentials is not \"true\".";
return false;
}
}
return true;
}
void parseAccessControlExposeHeadersAllowList(const String& headerValue, HTTPHeaderSet& headerSet)
{
Vector<String> headers;
headerValue.split(',', false, headers);
for (auto& header : headers) {
String strippedHeader = header.stripWhiteSpace();
if (!strippedHeader.isEmpty())
headerSet.add(strippedHeader);
}
}
} // namespace WebCore
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