CrossOriginAccessControl.cpp [plain text]
#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:
return true;
case HTTPHeaderName::ContentType: {
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, const String& referrer)
{
ResourceRequest preflightRequest(request.url());
static const double platformDefaultTimeout = 0;
preflightRequest.setTimeoutInterval(platformDefaultTimeout);
updateRequestForAccessControl(preflightRequest, securityOrigin, DoNotAllowStoredCredentials);
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 (const auto& headerField : requestHeaderFields.commonHeaders()) {
if (!isCrossOriginSafeRequestHeader(headerField.key, headerField.value))
unsafeHeaders.append(httpHeaderNameString(headerField.key).toStringWithoutCopying().convertToASCIILowercase());
}
for (const auto& headerField : requestHeaderFields.uncommonHeaders())
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);
}
preflightRequest.setHTTPHeaderField(HTTPHeaderName::AccessControlRequestHeaders, headerBuffer.toString());
}
return preflightRequest;
}
bool isValidCrossOriginRedirectionURL(const URL& redirectURL)
{
return SchemeRegistry::shouldTreatURLSchemeAsCORSEnabled(redirectURL.protocol().toStringWithoutCopying())
&& redirectURL.user().isEmpty()
&& redirectURL.pass().isEmpty();
}
void cleanRedirectedRequestForAccessControl(ResourceRequest& request)
{
request.clearHTTPContentType();
request.clearHTTPReferrer();
request.clearHTTPOrigin();
request.clearHTTPUserAgent();
request.clearHTTPAccept();
request.clearHTTPAcceptEncoding();
}
bool passesAccessControlCheck(const ResourceResponse& response, StoredCredentials includeCredentials, SecurityOrigin& securityOrigin, String& errorDescription)
{
const String& accessControlOriginString = response.httpHeaderField(HTTPHeaderName::AccessControlAllowOrigin);
if (accessControlOriginString == "*" && includeCredentials == DoNotAllowStoredCredentials)
return true;
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;
}
}