Home | History | Annotate | Download | only in loader 
      1 /*
      2  * Copyright (C) 2008, 2009 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/CrossOriginPreflightResultCache.h"
     29 
     30 #include "core/fetch/CrossOriginAccessControl.h"
     31 #include "platform/network/ResourceResponse.h"
     32 #include "wtf/CurrentTime.h"
     33 #include "wtf/MainThread.h"
     34 #include "wtf/StdLibExtras.h"
     35 
     36 namespace WebCore {
     37 
     38 using namespace std;
     39 
     40 // These values are at the discretion of the user agent.
     41 static const unsigned defaultPreflightCacheTimeoutSeconds = 5;
     42 static const unsigned maxPreflightCacheTimeoutSeconds = 600; // Should be short enough to minimize the risk of using a poisoned cache after switching to a secure network.
     43 
     44 static bool parseAccessControlMaxAge(const String& string, unsigned& expiryDelta)
     45 {
     46     // FIXME: this will not do the correct thing for a number starting with a '+'
     47     bool ok = false;
     48     expiryDelta = string.toUIntStrict(&ok);
     49     return ok;
     50 }
     51 
     52 template<class HashType>
     53 static void addToAccessControlAllowList(const String& string, unsigned start, unsigned end, HashSet<String, HashType>& set)
     54 {
     55     StringImpl* stringImpl = string.impl();
     56     if (!stringImpl)
     57         return;
     58 
     59     // Skip white space from start.
     60     while (start <= end && isSpaceOrNewline((*stringImpl)[start]))
     61         ++start;
     62 
     63     // only white space
     64     if (start > end)
     65         return;
     66 
     67     // Skip white space from end.
     68     while (end && isSpaceOrNewline((*stringImpl)[end]))
     69         --end;
     70 
     71     set.add(string.substring(start, end - start + 1));
     72 }
     73 
     74 template<class HashType>
     75 static bool parseAccessControlAllowList(const String& string, HashSet<String, HashType>& set)
     76 {
     77     unsigned start = 0;
     78     size_t end;
     79     while ((end = string.find(',', start)) != kNotFound) {
     80         if (start != end)
     81             addToAccessControlAllowList(string, start, end - 1, set);
     82         start = end + 1;
     83     }
     84     if (start != string.length())
     85         addToAccessControlAllowList(string, start, string.length() - 1, set);
     86 
     87     return true;
     88 }
     89 
     90 bool CrossOriginPreflightResultCacheItem::parse(const ResourceResponse& response, String& errorDescription)
     91 {
     92     m_methods.clear();
     93     if (!parseAccessControlAllowList(response.httpHeaderField("Access-Control-Allow-Methods"), m_methods)) {
     94         errorDescription = "Cannot parse Access-Control-Allow-Methods response header field.";
     95         return false;
     96     }
     97 
     98     m_headers.clear();
     99     if (!parseAccessControlAllowList(response.httpHeaderField("Access-Control-Allow-Headers"), m_headers)) {
    100         errorDescription = "Cannot parse Access-Control-Allow-Headers response header field.";
    101         return false;
    102     }
    103 
    104     unsigned expiryDelta;
    105     if (parseAccessControlMaxAge(response.httpHeaderField("Access-Control-Max-Age"), expiryDelta)) {
    106         if (expiryDelta > maxPreflightCacheTimeoutSeconds)
    107             expiryDelta = maxPreflightCacheTimeoutSeconds;
    108     } else
    109         expiryDelta = defaultPreflightCacheTimeoutSeconds;
    110 
    111     m_absoluteExpiryTime = currentTime() + expiryDelta;
    112     return true;
    113 }
    114 
    115 bool CrossOriginPreflightResultCacheItem::allowsCrossOriginMethod(const String& method, String& errorDescription) const
    116 {
    117     if (m_methods.contains(method) || isOnAccessControlSimpleRequestMethodWhitelist(method))
    118         return true;
    119 
    120     errorDescription = "Method " + method + " is not allowed by Access-Control-Allow-Methods.";
    121     return false;
    122 }
    123 
    124 bool CrossOriginPreflightResultCacheItem::allowsCrossOriginHeaders(const HTTPHeaderMap& requestHeaders, String& errorDescription) const
    125 {
    126     HTTPHeaderMap::const_iterator end = requestHeaders.end();
    127     for (HTTPHeaderMap::const_iterator it = requestHeaders.begin(); it != end; ++it) {
    128         if (!m_headers.contains(it->key) && !isOnAccessControlSimpleRequestHeaderWhitelist(it->key, it->value)) {
    129             errorDescription = "Request header field " + it->key.string() + " is not allowed by Access-Control-Allow-Headers.";
    130             return false;
    131         }
    132     }
    133     return true;
    134 }
    135 
    136 bool CrossOriginPreflightResultCacheItem::allowsRequest(StoredCredentials includeCredentials, const String& method, const HTTPHeaderMap& requestHeaders) const
    137 {
    138     String ignoredExplanation;
    139     if (m_absoluteExpiryTime < currentTime())
    140         return false;
    141     if (includeCredentials == AllowStoredCredentials && m_credentials == DoNotAllowStoredCredentials)
    142         return false;
    143     if (!allowsCrossOriginMethod(method, ignoredExplanation))
    144         return false;
    145     if (!allowsCrossOriginHeaders(requestHeaders, ignoredExplanation))
    146         return false;
    147     return true;
    148 }
    149 
    150 CrossOriginPreflightResultCache& CrossOriginPreflightResultCache::shared()
    151 {
    152     DEFINE_STATIC_LOCAL(CrossOriginPreflightResultCache, cache, ());
    153     ASSERT(isMainThread());
    154     return cache;
    155 }
    156 
    157 void CrossOriginPreflightResultCache::appendEntry(const String& origin, const KURL& url, PassOwnPtr<CrossOriginPreflightResultCacheItem> preflightResult)
    158 {
    159     ASSERT(isMainThread());
    160     m_preflightHashMap.set(make_pair(origin, url), preflightResult);
    161 }
    162 
    163 bool CrossOriginPreflightResultCache::canSkipPreflight(const String& origin, const KURL& url, StoredCredentials includeCredentials, const String& method, const HTTPHeaderMap& requestHeaders)
    164 {
    165     ASSERT(isMainThread());
    166     CrossOriginPreflightResultHashMap::iterator cacheIt = m_preflightHashMap.find(make_pair(origin, url));
    167     if (cacheIt == m_preflightHashMap.end())
    168         return false;
    169 
    170     if (cacheIt->value->allowsRequest(includeCredentials, method, requestHeaders))
    171         return true;
    172 
    173     m_preflightHashMap.remove(cacheIt);
    174     return false;
    175 }
    176 
    177 void CrossOriginPreflightResultCache::empty()
    178 {
    179     ASSERT(isMainThread());
    180     m_preflightHashMap.clear();
    181 }
    182 
    183 } // namespace WebCore
    184