Source/WebCore/loader/CrossOriginAccessControl.cpp - WebKit - Git at Google

 /*
  * 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 "CrossOriginEmbedderPolicy.h"
 #include "CrossOriginPreflightResultCache.h"
 #include "HTTPHeaderNames.h"
 #include "HTTPParsers.h"
 #include "LegacySchemeRegistry.h"
 #include "Page.h"
 #include "ResourceRequest.h"
 #include "ResourceResponse.h"
 #include "RuntimeApplicationChecks.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 isOnAccessControlSimpleRequestMethodAllowlist(const String& method)
 {
     return method == "GET" || method == "HEAD" || method == "POST";
 }

 bool isSimpleCrossOriginAccessRequest(const String& method, const HTTPHeaderMap& headerMap)
 {
     if (!isOnAccessControlSimpleRequestMethodAllowlist(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());
     preflightRequest.setFirstPartyForCookies(request.firstPartyForCookies());
     preflightRequest.setIsAppInitiated(request.isAppInitiated());
     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;
 }

 // https://html.spec.whatwg.org/multipage/urls-and-fetching.html#create-a-potential-cors-request
 CachedResourceRequest createPotentialAccessControlRequest(ResourceRequest&& request, ResourceLoaderOptions&& options, Document& document, const String& crossOriginAttribute, SameOriginFlag sameOriginFlag)
 {
     ASSERT(options.mode == FetchOptions::Mode::NoCors);
     if (!crossOriginAttribute.isNull())
         options.mode = FetchOptions::Mode::Cors;
     else if (sameOriginFlag == SameOriginFlag::Yes)
         options.mode = FetchOptions::Mode::SameOrigin;

     if (options.mode != FetchOptions::Mode::NoCors) {
         if (auto* page = document.page()) {
             if (page->shouldDisableCorsForRequestTo(request.url()))
                 options.mode = FetchOptions::Mode::NoCors;
         }
     }

     if (crossOriginAttribute.isNull()) {
         CachedResourceRequest cachedRequest { WTFMove(request), WTFMove(options) };
         cachedRequest.setOrigin(document.securityOrigin());
         return cachedRequest;
     }

     FetchOptions::Credentials credentials = equalLettersIgnoringASCIICase(crossOriginAttribute, "omit")
         ? FetchOptions::Credentials::Omit : equalLettersIgnoringASCIICase(crossOriginAttribute, "use-credentials")
         ? FetchOptions::Credentials::Include : FetchOptions::Credentials::SameOrigin;
     options.credentials = credentials;
     switch (credentials) {
     case FetchOptions::Credentials::Include:
         options.storedCredentialsPolicy = StoredCredentialsPolicy::Use;
         break;
     case FetchOptions::Credentials::SameOrigin:
         options.storedCredentialsPolicy = document.securityOrigin().canRequest(request.url()) ? StoredCredentialsPolicy::Use : StoredCredentialsPolicy::DoNotUse;
         break;
     case FetchOptions::Credentials::Omit:
         options.storedCredentialsPolicy = StoredCredentialsPolicy::DoNotUse;
     }

     CachedResourceRequest cachedRequest { WTFMove(request), WTFMove(options) };
     updateRequestForAccessControl(cachedRequest.resourceRequest(), document.securityOrigin(), options.storedCredentialsPolicy);
     return cachedRequest;
 }

 String validateCrossOriginRedirectionURL(const URL& redirectURL)
 {
     if (!LegacySchemeRegistry::shouldTreatURLSchemeAsCORSEnabled(redirectURL.protocol().toStringWithoutCopying()))
         return makeString("not allowed to follow a cross-origin CORS redirection with non CORS scheme");

     if (redirectURL.hasCredentials())
         return makeString("redirection URL ", redirectURL.string(), " has credentials");

     return { };
 }

 OptionSet<HTTPHeadersToKeepFromCleaning> httpHeadersToKeepFromCleaning(const HTTPHeaderMap& headers)
 {
     OptionSet<HTTPHeadersToKeepFromCleaning> headersToKeep;
     if (headers.contains(HTTPHeaderName::ContentType))
         headersToKeep.add(HTTPHeadersToKeepFromCleaning::ContentType);
     if (headers.contains(HTTPHeaderName::Referer))
         headersToKeep.add(HTTPHeadersToKeepFromCleaning::Referer);
     if (headers.contains(HTTPHeaderName::Origin))
         headersToKeep.add(HTTPHeadersToKeepFromCleaning::Origin);
     if (headers.contains(HTTPHeaderName::UserAgent))
         headersToKeep.add(HTTPHeadersToKeepFromCleaning::UserAgent);
     if (headers.contains(HTTPHeaderName::AcceptEncoding))
         headersToKeep.add(HTTPHeadersToKeepFromCleaning::AcceptEncoding);
     return headersToKeep;
 }

 void cleanHTTPRequestHeadersForAccessControl(ResourceRequest& request, OptionSet<HTTPHeadersToKeepFromCleaning> headersToKeep)
 {
     // Remove headers that may have been added by the network layer that cause access control to fail.
     if (!headersToKeep.contains(HTTPHeadersToKeepFromCleaning::ContentType)) {
         auto contentType = request.httpContentType();
         if (!contentType.isNull() && !isCrossOriginSafeRequestHeader(HTTPHeaderName::ContentType, contentType))
             request.clearHTTPContentType();
     }
     if (!headersToKeep.contains(HTTPHeadersToKeepFromCleaning::Referer))
         request.clearHTTPReferrer();
     if (!headersToKeep.contains(HTTPHeadersToKeepFromCleaning::Origin))
         request.clearHTTPOrigin();
     if (!headersToKeep.contains(HTTPHeadersToKeepFromCleaning::UserAgent))
         request.clearHTTPUserAgent();
     if (!headersToKeep.contains(HTTPHeadersToKeepFromCleaning::AcceptEncoding))
         request.clearHTTPAcceptEncoding();
 }

 CrossOriginAccessControlCheckDisabler& CrossOriginAccessControlCheckDisabler::singleton()
 {
     ASSERT(!isInNetworkProcess());
     static NeverDestroyed<CrossOriginAccessControlCheckDisabler> disabler;
     return disabler.get();
 }

 void CrossOriginAccessControlCheckDisabler::setCrossOriginAccessControlCheckEnabled(bool enabled)
 {
     ASSERT(!isInNetworkProcess());
     m_accessControlCheckEnabled = enabled;
 }

 bool CrossOriginAccessControlCheckDisabler::crossOriginAccessControlCheckEnabled() const
 {
     ASSERT(!isInNetworkProcess());
     return m_accessControlCheckEnabled;
 }

 Expected<void, String> passesAccessControlCheck(const ResourceResponse& response, StoredCredentialsPolicy storedCredentialsPolicy, const SecurityOrigin& securityOrigin, const CrossOriginAccessControlCheckDisabler* checkDisabler)
 {
     // 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);
     bool starAllowed = storedCredentialsPolicy == StoredCredentialsPolicy::DoNotUse;
     if (!starAllowed)
         starAllowed = checkDisabler && !checkDisabler->crossOriginAccessControlCheckEnabled();
     if (accessControlOriginString == "*" && starAllowed)
         return { };

     String securityOriginString = securityOrigin.toString();
     if (accessControlOriginString != securityOriginString) {
         if (accessControlOriginString == "*")
             return makeUnexpected("Cannot use wildcard in Access-Control-Allow-Origin when credentials flag is true."_s);
         if (accessControlOriginString.find(',') != notFound)
             return makeUnexpected("Access-Control-Allow-Origin cannot contain more than one origin."_s);
         return makeUnexpected(makeString("Origin ", securityOriginString, " is not allowed by Access-Control-Allow-Origin."));
     }

     if (storedCredentialsPolicy == StoredCredentialsPolicy::Use) {
         const String& accessControlCredentialsString = response.httpHeaderField(HTTPHeaderName::AccessControlAllowCredentials);
         if (accessControlCredentialsString != "true")
             return makeUnexpected("Credentials flag is true, but Access-Control-Allow-Credentials is not \"true\"."_s);
     }

     return { };
 }

 Expected<void, String> validatePreflightResponse(PAL::SessionID sessionID, const ResourceRequest& request, const ResourceResponse& response, StoredCredentialsPolicy storedCredentialsPolicy, const SecurityOrigin& securityOrigin, const CrossOriginAccessControlCheckDisabler* checkDisabler)
 {
     if (!response.isSuccessful())
         return makeUnexpected("Preflight response is not successful"_s);

     auto accessControlCheckResult = passesAccessControlCheck(response, storedCredentialsPolicy, securityOrigin, checkDisabler);
     if (!accessControlCheckResult)
         return accessControlCheckResult;

     auto result = CrossOriginPreflightResultCacheItem::create(storedCredentialsPolicy, response);
     if (!result.has_value())
         return makeUnexpected(WTFMove(result.error()));

     auto entry = WTFMove(result.value());
     auto errorDescription = entry->validateMethodAndHeaders(request.httpMethod(), request.httpHeaderFields());
     CrossOriginPreflightResultCache::singleton().appendEntry(sessionID, securityOrigin.toString(), request.url(), entry.moveToUniquePtr());

     if (errorDescription)
         return makeUnexpected(WTFMove(*errorDescription));

     return { };
 }

 // https://fetch.spec.whatwg.org/#cross-origin-resource-policy-internal-check
 static inline bool shouldCrossOriginResourcePolicyCancelLoad(CrossOriginEmbedderPolicyValue coep, const SecurityOrigin& origin, const ResourceResponse& response, ForNavigation forNavigation)
 {
     if (forNavigation == ForNavigation::Yes && coep != CrossOriginEmbedderPolicyValue::RequireCORP)
         return false;

     if (response.isNull() || origin.canRequest(response.url()))
         return false;

     auto policy = parseCrossOriginResourcePolicyHeader(response.httpHeaderField(HTTPHeaderName::CrossOriginResourcePolicy));

     // https://fetch.spec.whatwg.org/#cross-origin-resource-policy-internal-check (step 4).
     if ((policy == CrossOriginResourcePolicy::None || policy == CrossOriginResourcePolicy::Invalid) && coep == CrossOriginEmbedderPolicyValue::RequireCORP)
         return true;

     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;
 }

 std::optional<ResourceError> validateCrossOriginResourcePolicy(CrossOriginEmbedderPolicyValue coep, const SecurityOrigin& origin, const URL& requestURL, const ResourceResponse& response, ForNavigation forNavigation)
 {
     if (shouldCrossOriginResourcePolicyCancelLoad(coep, origin, response, forNavigation))
         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 std::nullopt;
 }

 std::optional<ResourceError> validateRangeRequestedFlag(const ResourceRequest& request, const ResourceResponse& response)
 {
     if (response.isRangeRequested() && response.httpStatusCode() == 206 && response.type() == ResourceResponse::Type::Opaque && !request.hasHTTPHeaderField(HTTPHeaderName::Range))
         return ResourceError({ }, 0, response.url(), { }, ResourceError::Type::General);
     return std::nullopt;
 }

 } // namespace WebCore
	/*
	* 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 "CrossOriginEmbedderPolicy.h"
	#include "CrossOriginPreflightResultCache.h"
	#include "HTTPHeaderNames.h"
	#include "HTTPParsers.h"
	#include "LegacySchemeRegistry.h"
	#include "Page.h"
	#include "ResourceRequest.h"
	#include "ResourceResponse.h"
	#include "RuntimeApplicationChecks.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 isOnAccessControlSimpleRequestMethodAllowlist(const String& method)
	{
	return method == "GET" \|\| method == "HEAD" \|\| method == "POST";
	}

	bool isSimpleCrossOriginAccessRequest(const String& method, const HTTPHeaderMap& headerMap)
	{
	if (!isOnAccessControlSimpleRequestMethodAllowlist(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());
	preflightRequest.setFirstPartyForCookies(request.firstPartyForCookies());
	preflightRequest.setIsAppInitiated(request.isAppInitiated());
	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;
	}

	// https://html.spec.whatwg.org/multipage/urls-and-fetching.html#create-a-potential-cors-request
	CachedResourceRequest createPotentialAccessControlRequest(ResourceRequest&& request, ResourceLoaderOptions&& options, Document& document, const String& crossOriginAttribute, SameOriginFlag sameOriginFlag)
	{
	ASSERT(options.mode == FetchOptions::Mode::NoCors);
	if (!crossOriginAttribute.isNull())
	options.mode = FetchOptions::Mode::Cors;
	else if (sameOriginFlag == SameOriginFlag::Yes)
	options.mode = FetchOptions::Mode::SameOrigin;

	if (options.mode != FetchOptions::Mode::NoCors) {
	if (auto* page = document.page()) {
	if (page->shouldDisableCorsForRequestTo(request.url()))
	options.mode = FetchOptions::Mode::NoCors;
	}
	}

	if (crossOriginAttribute.isNull()) {
	CachedResourceRequest cachedRequest { WTFMove(request), WTFMove(options) };
	cachedRequest.setOrigin(document.securityOrigin());
	return cachedRequest;
	}

	FetchOptions::Credentials credentials = equalLettersIgnoringASCIICase(crossOriginAttribute, "omit")
	? FetchOptions::Credentials::Omit : equalLettersIgnoringASCIICase(crossOriginAttribute, "use-credentials")
	? FetchOptions::Credentials::Include : FetchOptions::Credentials::SameOrigin;
	options.credentials = credentials;
	switch (credentials) {
	case FetchOptions::Credentials::Include:
	options.storedCredentialsPolicy = StoredCredentialsPolicy::Use;
	break;
	case FetchOptions::Credentials::SameOrigin:
	options.storedCredentialsPolicy = document.securityOrigin().canRequest(request.url()) ? StoredCredentialsPolicy::Use : StoredCredentialsPolicy::DoNotUse;
	break;
	case FetchOptions::Credentials::Omit:
	options.storedCredentialsPolicy = StoredCredentialsPolicy::DoNotUse;
	}

	CachedResourceRequest cachedRequest { WTFMove(request), WTFMove(options) };
	updateRequestForAccessControl(cachedRequest.resourceRequest(), document.securityOrigin(), options.storedCredentialsPolicy);
	return cachedRequest;
	}

	String validateCrossOriginRedirectionURL(const URL& redirectURL)
	{
	if (!LegacySchemeRegistry::shouldTreatURLSchemeAsCORSEnabled(redirectURL.protocol().toStringWithoutCopying()))
	return makeString("not allowed to follow a cross-origin CORS redirection with non CORS scheme");

	if (redirectURL.hasCredentials())
	return makeString("redirection URL ", redirectURL.string(), " has credentials");

	return { };
	}

	OptionSet<HTTPHeadersToKeepFromCleaning> httpHeadersToKeepFromCleaning(const HTTPHeaderMap& headers)
	{
	OptionSet<HTTPHeadersToKeepFromCleaning> headersToKeep;
	if (headers.contains(HTTPHeaderName::ContentType))
	headersToKeep.add(HTTPHeadersToKeepFromCleaning::ContentType);
	if (headers.contains(HTTPHeaderName::Referer))
	headersToKeep.add(HTTPHeadersToKeepFromCleaning::Referer);
	if (headers.contains(HTTPHeaderName::Origin))
	headersToKeep.add(HTTPHeadersToKeepFromCleaning::Origin);
	if (headers.contains(HTTPHeaderName::UserAgent))
	headersToKeep.add(HTTPHeadersToKeepFromCleaning::UserAgent);
	if (headers.contains(HTTPHeaderName::AcceptEncoding))
	headersToKeep.add(HTTPHeadersToKeepFromCleaning::AcceptEncoding);
	return headersToKeep;
	}

	void cleanHTTPRequestHeadersForAccessControl(ResourceRequest& request, OptionSet<HTTPHeadersToKeepFromCleaning> headersToKeep)
	{
	// Remove headers that may have been added by the network layer that cause access control to fail.
	if (!headersToKeep.contains(HTTPHeadersToKeepFromCleaning::ContentType)) {
	auto contentType = request.httpContentType();
	if (!contentType.isNull() && !isCrossOriginSafeRequestHeader(HTTPHeaderName::ContentType, contentType))
	request.clearHTTPContentType();
	}
	if (!headersToKeep.contains(HTTPHeadersToKeepFromCleaning::Referer))
	request.clearHTTPReferrer();
	if (!headersToKeep.contains(HTTPHeadersToKeepFromCleaning::Origin))
	request.clearHTTPOrigin();
	if (!headersToKeep.contains(HTTPHeadersToKeepFromCleaning::UserAgent))
	request.clearHTTPUserAgent();
	if (!headersToKeep.contains(HTTPHeadersToKeepFromCleaning::AcceptEncoding))
	request.clearHTTPAcceptEncoding();
	}

	CrossOriginAccessControlCheckDisabler& CrossOriginAccessControlCheckDisabler::singleton()
	{
	ASSERT(!isInNetworkProcess());
	static NeverDestroyed<CrossOriginAccessControlCheckDisabler> disabler;
	return disabler.get();
	}

	void CrossOriginAccessControlCheckDisabler::setCrossOriginAccessControlCheckEnabled(bool enabled)
	{
	ASSERT(!isInNetworkProcess());
	m_accessControlCheckEnabled = enabled;
	}

	bool CrossOriginAccessControlCheckDisabler::crossOriginAccessControlCheckEnabled() const
	{
	ASSERT(!isInNetworkProcess());
	return m_accessControlCheckEnabled;
	}

	Expected<void, String> passesAccessControlCheck(const ResourceResponse& response, StoredCredentialsPolicy storedCredentialsPolicy, const SecurityOrigin& securityOrigin, const CrossOriginAccessControlCheckDisabler* checkDisabler)
	{
	// 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);
	bool starAllowed = storedCredentialsPolicy == StoredCredentialsPolicy::DoNotUse;
	if (!starAllowed)
	starAllowed = checkDisabler && !checkDisabler->crossOriginAccessControlCheckEnabled();
	if (accessControlOriginString == "*" && starAllowed)
	return { };

	String securityOriginString = securityOrigin.toString();
	if (accessControlOriginString != securityOriginString) {
	if (accessControlOriginString == "*")
	return makeUnexpected("Cannot use wildcard in Access-Control-Allow-Origin when credentials flag is true."_s);
	if (accessControlOriginString.find(',') != notFound)
	return makeUnexpected("Access-Control-Allow-Origin cannot contain more than one origin."_s);
	return makeUnexpected(makeString("Origin ", securityOriginString, " is not allowed by Access-Control-Allow-Origin."));
	}

	if (storedCredentialsPolicy == StoredCredentialsPolicy::Use) {
	const String& accessControlCredentialsString = response.httpHeaderField(HTTPHeaderName::AccessControlAllowCredentials);
	if (accessControlCredentialsString != "true")
	return makeUnexpected("Credentials flag is true, but Access-Control-Allow-Credentials is not \"true\"."_s);
	}

	return { };
	}

	Expected<void, String> validatePreflightResponse(PAL::SessionID sessionID, const ResourceRequest& request, const ResourceResponse& response, StoredCredentialsPolicy storedCredentialsPolicy, const SecurityOrigin& securityOrigin, const CrossOriginAccessControlCheckDisabler* checkDisabler)
	{
	if (!response.isSuccessful())
	return makeUnexpected("Preflight response is not successful"_s);

	auto accessControlCheckResult = passesAccessControlCheck(response, storedCredentialsPolicy, securityOrigin, checkDisabler);
	if (!accessControlCheckResult)
	return accessControlCheckResult;

	auto result = CrossOriginPreflightResultCacheItem::create(storedCredentialsPolicy, response);
	if (!result.has_value())
	return makeUnexpected(WTFMove(result.error()));

	auto entry = WTFMove(result.value());
	auto errorDescription = entry->validateMethodAndHeaders(request.httpMethod(), request.httpHeaderFields());
	CrossOriginPreflightResultCache::singleton().appendEntry(sessionID, securityOrigin.toString(), request.url(), entry.moveToUniquePtr());

	if (errorDescription)
	return makeUnexpected(WTFMove(*errorDescription));

	return { };
	}

	// https://fetch.spec.whatwg.org/#cross-origin-resource-policy-internal-check
	static inline bool shouldCrossOriginResourcePolicyCancelLoad(CrossOriginEmbedderPolicyValue coep, const SecurityOrigin& origin, const ResourceResponse& response, ForNavigation forNavigation)
	{
	if (forNavigation == ForNavigation::Yes && coep != CrossOriginEmbedderPolicyValue::RequireCORP)
	return false;

	if (response.isNull() \|\| origin.canRequest(response.url()))
	return false;

	auto policy = parseCrossOriginResourcePolicyHeader(response.httpHeaderField(HTTPHeaderName::CrossOriginResourcePolicy));

	// https://fetch.spec.whatwg.org/#cross-origin-resource-policy-internal-check (step 4).
	if ((policy == CrossOriginResourcePolicy::None \|\| policy == CrossOriginResourcePolicy::Invalid) && coep == CrossOriginEmbedderPolicyValue::RequireCORP)
	return true;

	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;
	}

	std::optional<ResourceError> validateCrossOriginResourcePolicy(CrossOriginEmbedderPolicyValue coep, const SecurityOrigin& origin, const URL& requestURL, const ResourceResponse& response, ForNavigation forNavigation)
	{
	if (shouldCrossOriginResourcePolicyCancelLoad(coep, origin, response, forNavigation))
	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 std::nullopt;
	}

	std::optional<ResourceError> validateRangeRequestedFlag(const ResourceRequest& request, const ResourceResponse& response)
	{
	if (response.isRangeRequested() && response.httpStatusCode() == 206 && response.type() == ResourceResponse::Type::Opaque && !request.hasHTTPHeaderField(HTTPHeaderName::Range))
	return ResourceError({ }, 0, response.url(), { }, ResourceError::Type::General);
	return std::nullopt;
	}

	} // namespace WebCore