third_party/WebKit/Source/core/loader/CrossOriginPreflightResultCache.cpp

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