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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 "CachedResourceRequest.h"
#include "CrossOriginPreflightResultCache.h"
#include "HTTPHeaderNames.h"
#include "HTTPParsers.h"
#include "LegacySchemeRegistry.h"
#include "ResourceRequest.h"
#include "ResourceResponse.h"
#include "SecurityOrigin.h"
#include "SecurityPolicy.h"
#include <mutex>
#include <wtf/NeverDestroyed.h>
#include <wtf/text/AtomString.h>
#include <wtf/text/StringBuilder.h>
namespace WebCore {
bool isOnAccessControlSimpleRequestMethodWhitelist(const String& method)
{
return method == "GET" || method == "HEAD" || method == "POST";
}
bool isSimpleCrossOriginAccessRequest(const String& method, const HTTPHeaderMap& headerMap)
{
if (!isOnAccessControlSimpleRequestMethodWhitelist(method))
return false;
for (const auto& header : headerMap) {
if (!header.keyAsHTTPHeaderName || !isCrossOriginSafeRequestHeader(header.keyAsHTTPHeaderName.value(), header.value))
return false;
}
return true;
}
void updateRequestReferrer(ResourceRequest& request, ReferrerPolicy referrerPolicy, const String& outgoingReferrer)
{
String newOutgoingReferrer = SecurityPolicy::generateReferrerHeader(referrerPolicy, request.url(), outgoingReferrer);
if (newOutgoingReferrer.isEmpty())
request.clearHTTPReferrer();
else
request.setHTTPReferrer(newOutgoingReferrer);
}
void updateRequestForAccessControl(ResourceRequest& request, SecurityOrigin& securityOrigin, StoredCredentialsPolicy storedCredentialsPolicy)
{
request.removeCredentials();
request.setAllowCookies(storedCredentialsPolicy == StoredCredentialsPolicy::Use);
request.setHTTPOrigin(securityOrigin.toString());
}
ResourceRequest createAccessControlPreflightRequest(const ResourceRequest& request, SecurityOrigin& securityOrigin, const String& referrer)
{
ResourceRequest preflightRequest(request.url());
static const double platformDefaultTimeout = 0;
preflightRequest.setTimeoutInterval(platformDefaultTimeout);
updateRequestForAccessControl(preflightRequest, securityOrigin, StoredCredentialsPolicy::DoNotUse);
preflightRequest.setHTTPMethod("OPTIONS");
preflightRequest.setHTTPHeaderField(HTTPHeaderName::AccessControlRequestMethod, request.httpMethod());
preflightRequest.setPriority(request.priority());
if (!referrer.isNull())
preflightRequest.setHTTPReferrer(referrer);
const HTTPHeaderMap& requestHeaderFields = request.httpHeaderFields();
if (!requestHeaderFields.isEmpty()) {
Vector<String> unsafeHeaders;
for (auto& headerField : requestHeaderFields) {
if (!headerField.keyAsHTTPHeaderName || !isCrossOriginSafeRequestHeader(*headerField.keyAsHTTPHeaderName, headerField.value))
unsafeHeaders.append(headerField.key.convertToASCIILowercase());
}
std::sort(unsafeHeaders.begin(), unsafeHeaders.end(), WTF::codePointCompareLessThan);
StringBuilder headerBuffer;
bool appendComma = false;
for (const auto& headerField : unsafeHeaders) {
if (appendComma)
headerBuffer.append(',');
else
appendComma = true;
headerBuffer.append(headerField);
}
if (!headerBuffer.isEmpty())
preflightRequest.setHTTPHeaderField(HTTPHeaderName::AccessControlRequestHeaders, headerBuffer.toString());
}
return preflightRequest;
}
CachedResourceRequest createPotentialAccessControlRequest(ResourceRequest&& request, Document& document, const String& crossOriginAttribute, ResourceLoaderOptions&& options)
{
// FIXME: This does not match the algorithm "create a potential-CORS request":
// <https://html.spec.whatwg.org/multipage/urls-and-fetching.html#create-a-potential-cors-request> (31 August 2018).
auto cachedRequest = CachedResourceRequest { WTFMove(request), WTFMove(options) };
cachedRequest.deprecatedSetAsPotentiallyCrossOrigin(crossOriginAttribute, document);
return cachedRequest;
}
bool isValidCrossOriginRedirectionURL(const URL& redirectURL)
{
return LegacySchemeRegistry::shouldTreatURLSchemeAsCORSEnabled(redirectURL.protocol().toStringWithoutCopying())
&& redirectURL.user().isEmpty()
&& redirectURL.pass().isEmpty();
}
HTTPHeaderNameSet httpHeadersToKeepFromCleaning(const HTTPHeaderMap& headers)
{
HTTPHeaderNameSet headersToKeep;
if (headers.contains(HTTPHeaderName::ContentType))
headersToKeep.add(HTTPHeaderName::ContentType);
if (headers.contains(HTTPHeaderName::Referer))
headersToKeep.add(HTTPHeaderName::Referer);
if (headers.contains(HTTPHeaderName::Origin))
headersToKeep.add(HTTPHeaderName::Origin);
if (headers.contains(HTTPHeaderName::UserAgent))
headersToKeep.add(HTTPHeaderName::UserAgent);
if (headers.contains(HTTPHeaderName::AcceptEncoding))
headersToKeep.add(HTTPHeaderName::AcceptEncoding);
return headersToKeep;
}
void cleanHTTPRequestHeadersForAccessControl(ResourceRequest& request, const HashSet<HTTPHeaderName, WTF::IntHash<HTTPHeaderName>, WTF::StrongEnumHashTraits<HTTPHeaderName>>& headersToKeep)
{
// Remove headers that may have been added by the network layer that cause access control to fail.
if (!headersToKeep.contains(HTTPHeaderName::ContentType) && !isCrossOriginSafeRequestHeader(HTTPHeaderName::ContentType, request.httpContentType()))
request.clearHTTPContentType();
if (!headersToKeep.contains(HTTPHeaderName::Referer))
request.clearHTTPReferrer();
if (!headersToKeep.contains(HTTPHeaderName::Origin))
request.clearHTTPOrigin();
if (!headersToKeep.contains(HTTPHeaderName::UserAgent))
request.clearHTTPUserAgent();
if (!headersToKeep.contains(HTTPHeaderName::AcceptEncoding))
request.clearHTTPAcceptEncoding();
}
bool passesAccessControlCheck(const ResourceResponse& response, StoredCredentialsPolicy storedCredentialsPolicy, 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 == "*" && storedCredentialsPolicy == StoredCredentialsPolicy::DoNotUse)
return true;
String securityOriginString = securityOrigin.toString();
if (accessControlOriginString != securityOriginString) {
if (accessControlOriginString == "*")
errorDescription = "Cannot use wildcard in Access-Control-Allow-Origin when credentials flag is true."_s;
else if (accessControlOriginString.find(',') != notFound)
errorDescription = "Access-Control-Allow-Origin cannot contain more than one origin."_s;
else
errorDescription = makeString("Origin ", securityOriginString, " is not allowed by Access-Control-Allow-Origin.");
return false;
}
if (storedCredentialsPolicy == StoredCredentialsPolicy::Use) {
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;
}
bool validatePreflightResponse(const ResourceRequest& request, const ResourceResponse& response, StoredCredentialsPolicy storedCredentialsPolicy, SecurityOrigin& securityOrigin, String& errorDescription)
{
if (!response.isSuccessful()) {
errorDescription = "Preflight response is not successful"_s;
return false;
}
if (!passesAccessControlCheck(response, storedCredentialsPolicy, securityOrigin, errorDescription))
return false;
auto result = makeUnique<CrossOriginPreflightResultCacheItem>(storedCredentialsPolicy);
if (!result->parse(response)
|| !result->allowsCrossOriginMethod(request.httpMethod(), storedCredentialsPolicy, errorDescription)
|| !result->allowsCrossOriginHeaders(request.httpHeaderFields(), storedCredentialsPolicy, errorDescription)) {
return false;
}
CrossOriginPreflightResultCache::singleton().appendEntry(securityOrigin.toString(), request.url(), WTFMove(result));
return true;
}
static inline bool shouldCrossOriginResourcePolicyCancelLoad(const SecurityOrigin& origin, const ResourceResponse& response)
{
if (origin.canRequest(response.url()))
return false;
auto policy = parseCrossOriginResourcePolicyHeader(response.httpHeaderField(HTTPHeaderName::CrossOriginResourcePolicy));
if (policy == CrossOriginResourcePolicy::SameOrigin)
return true;
if (policy == CrossOriginResourcePolicy::SameSite) {
if (origin.isUnique())
return true;
#if ENABLE(PUBLIC_SUFFIX_LIST)
if (!RegistrableDomain::uncheckedCreateFromHost(origin.host()).matches(response.url()))
return true;
#endif
if (origin.protocol() == "http" && response.url().protocol() == "https")
return true;
}
return false;
}
Optional<ResourceError> validateCrossOriginResourcePolicy(const SecurityOrigin& origin, const URL& requestURL, const ResourceResponse& response)
{
if (shouldCrossOriginResourcePolicyCancelLoad(origin, response))
return ResourceError { errorDomainWebKitInternal, 0, requestURL, makeString("Cancelled load to ", response.url().stringCenterEllipsizedToLength(), " because it violates the resource's Cross-Origin-Resource-Policy response header."), ResourceError::Type::AccessControl };
return WTF::nullopt;
}
} // namespace WebCore