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      1 /*
      2  * Copyright (C) 2008 Apple Inc. All Rights Reserved.
      3  *
      4  * Redistribution and use in source and binary forms, with or without
      5  * modification, are permitted provided that the following conditions
      6  * are met:
      7  * 1. Redistributions of source code must retain the above copyright
      8  *    notice, this list of conditions and the following disclaimer.
      9  * 2. Redistributions in binary form must reproduce the above copyright
     10  *    notice, this list of conditions and the following disclaimer in the
     11  *    documentation and/or other materials provided with the distribution.
     12  *
     13  * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY
     14  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     15  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     16  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
     17  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
     18  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
     19  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
     20  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
     21  * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     22  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
     23  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     24  *
     25  */
     26 
     27 #include "config.h"
     28 #include "core/loader/CrossOriginAccessControl.h"
     29 
     30 #include "core/platform/network/HTTPParsers.h"
     31 #include "core/platform/network/ResourceRequest.h"
     32 #include "core/platform/network/ResourceResponse.h"
     33 #include "weborigin/SecurityOrigin.h"
     34 #include "wtf/Threading.h"
     35 #include "wtf/text/AtomicString.h"
     36 #include "wtf/text/StringBuilder.h"
     37 
     38 namespace WebCore {
     39 
     40 bool isOnAccessControlSimpleRequestMethodWhitelist(const String& method)
     41 {
     42     return method == "GET" || method == "HEAD" || method == "POST";
     43 }
     44 
     45 bool isOnAccessControlSimpleRequestHeaderWhitelist(const String& name, const String& value)
     46 {
     47     if (equalIgnoringCase(name, "accept")
     48         || equalIgnoringCase(name, "accept-language")
     49         || equalIgnoringCase(name, "content-language")
     50         || equalIgnoringCase(name, "origin")
     51         || equalIgnoringCase(name, "referer"))
     52         return true;
     53 
     54     // Preflight is required for MIME types that can not be sent via form submission.
     55     if (equalIgnoringCase(name, "content-type")) {
     56         String mimeType = extractMIMETypeFromMediaType(value);
     57         return equalIgnoringCase(mimeType, "application/x-www-form-urlencoded")
     58             || equalIgnoringCase(mimeType, "multipart/form-data")
     59             || equalIgnoringCase(mimeType, "text/plain");
     60     }
     61 
     62     return false;
     63 }
     64 
     65 bool isSimpleCrossOriginAccessRequest(const String& method, const HTTPHeaderMap& headerMap)
     66 {
     67     if (!isOnAccessControlSimpleRequestMethodWhitelist(method))
     68         return false;
     69 
     70     HTTPHeaderMap::const_iterator end = headerMap.end();
     71     for (HTTPHeaderMap::const_iterator it = headerMap.begin(); it != end; ++it) {
     72         if (!isOnAccessControlSimpleRequestHeaderWhitelist(it->key, it->value))
     73             return false;
     74     }
     75 
     76     return true;
     77 }
     78 
     79 static PassOwnPtr<HTTPHeaderSet> createAllowedCrossOriginResponseHeadersSet()
     80 {
     81     OwnPtr<HTTPHeaderSet> headerSet = adoptPtr(new HashSet<String, CaseFoldingHash>);
     82 
     83     headerSet->add("cache-control");
     84     headerSet->add("content-language");
     85     headerSet->add("content-type");
     86     headerSet->add("expires");
     87     headerSet->add("last-modified");
     88     headerSet->add("pragma");
     89 
     90     return headerSet.release();
     91 }
     92 
     93 bool isOnAccessControlResponseHeaderWhitelist(const String& name)
     94 {
     95     AtomicallyInitializedStatic(HTTPHeaderSet*, allowedCrossOriginResponseHeaders = createAllowedCrossOriginResponseHeadersSet().leakPtr());
     96 
     97     return allowedCrossOriginResponseHeaders->contains(name);
     98 }
     99 
    100 void updateRequestForAccessControl(ResourceRequest& request, SecurityOrigin* securityOrigin, StoredCredentials allowCredentials)
    101 {
    102     request.removeCredentials();
    103     request.setAllowCookies(allowCredentials == AllowStoredCredentials);
    104 
    105     if (securityOrigin)
    106         request.setHTTPOrigin(securityOrigin->toString());
    107 }
    108 
    109 ResourceRequest createAccessControlPreflightRequest(const ResourceRequest& request, SecurityOrigin* securityOrigin)
    110 {
    111     ResourceRequest preflightRequest(request.url());
    112     updateRequestForAccessControl(preflightRequest, securityOrigin, DoNotAllowStoredCredentials);
    113     preflightRequest.setHTTPMethod("OPTIONS");
    114     preflightRequest.setHTTPHeaderField("Access-Control-Request-Method", request.httpMethod());
    115     preflightRequest.setPriority(request.priority());
    116 
    117     const HTTPHeaderMap& requestHeaderFields = request.httpHeaderFields();
    118 
    119     if (requestHeaderFields.size() > 0) {
    120         StringBuilder headerBuffer;
    121         HTTPHeaderMap::const_iterator it = requestHeaderFields.begin();
    122         headerBuffer.append(it->key);
    123         ++it;
    124 
    125         HTTPHeaderMap::const_iterator end = requestHeaderFields.end();
    126         for (; it != end; ++it) {
    127             headerBuffer.append(',');
    128             headerBuffer.append(' ');
    129             headerBuffer.append(it->key);
    130         }
    131 
    132         preflightRequest.setHTTPHeaderField("Access-Control-Request-Headers", headerBuffer.toString().lower());
    133     }
    134 
    135     return preflightRequest;
    136 }
    137 
    138 bool passesAccessControlCheck(const ResourceResponse& response, StoredCredentials includeCredentials, SecurityOrigin* securityOrigin, String& errorDescription)
    139 {
    140     AtomicallyInitializedStatic(AtomicString&, accessControlAllowOrigin = *new AtomicString("access-control-allow-origin", AtomicString::ConstructFromLiteral));
    141     AtomicallyInitializedStatic(AtomicString&, accessControlAllowCredentials = *new AtomicString("access-control-allow-credentials", AtomicString::ConstructFromLiteral));
    142 
    143     // A wildcard Access-Control-Allow-Origin can not be used if credentials are to be sent,
    144     // even with Access-Control-Allow-Credentials set to true.
    145     const String& accessControlOriginString = response.httpHeaderField(accessControlAllowOrigin);
    146     if (accessControlOriginString == "*" && includeCredentials == DoNotAllowStoredCredentials)
    147         return true;
    148 
    149     // FIXME: Access-Control-Allow-Origin can contain a list of origins.
    150     if (accessControlOriginString != securityOrigin->toString()) {
    151         if (accessControlOriginString == "*")
    152             errorDescription = "Cannot use wildcard in Access-Control-Allow-Origin when credentials flag is true.";
    153         else
    154             errorDescription =  "Origin " + securityOrigin->toString() + " is not allowed by Access-Control-Allow-Origin.";
    155         return false;
    156     }
    157 
    158     if (includeCredentials == AllowStoredCredentials) {
    159         const String& accessControlCredentialsString = response.httpHeaderField(accessControlAllowCredentials);
    160         if (accessControlCredentialsString != "true") {
    161             errorDescription = "Credentials flag is true, but Access-Control-Allow-Credentials is not \"true\".";
    162             return false;
    163         }
    164     }
    165 
    166     return true;
    167 }
    168 
    169 bool passesPreflightStatusCheck(const ResourceResponse& response, String& errorDescription)
    170 {
    171     if (response.httpStatusCode() < 200 || response.httpStatusCode() >= 400) {
    172         errorDescription = "Invalid HTTP status code " + String::number(response.httpStatusCode());
    173         return false;
    174     }
    175 
    176     return true;
    177 }
    178 
    179 void parseAccessControlExposeHeadersAllowList(const String& headerValue, HTTPHeaderSet& headerSet)
    180 {
    181     Vector<String> headers;
    182     headerValue.split(',', false, headers);
    183     for (unsigned headerCount = 0; headerCount < headers.size(); headerCount++) {
    184         String strippedHeader = headers[headerCount].stripWhiteSpace();
    185         if (!strippedHeader.isEmpty())
    186             headerSet.add(strippedHeader);
    187     }
    188 }
    189 
    190 } // namespace WebCore
    191