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 "CrossOriginPreflightResultCache.h"
29
30 #include "CrossOriginAccessControl.h"
31 #include "ResourceResponse.h"
32 #include <wtf/CurrentTime.h>
33 #include <wtf/StdLibExtras.h>
34 #include <wtf/Threading.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
parseAccessControlMaxAge(const String & string,unsigned & expiryDelta)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>
addToAccessControlAllowList(const String & string,unsigned start,unsigned end,HashSet<String,HashType> & set)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>
parseAccessControlAllowList(const String & string,HashSet<String,HashType> & set)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)) != notFound) {
80 if (start == end)
81 return false;
82
83 addToAccessControlAllowList(string, start, end - 1, set);
84 start = end + 1;
85 }
86 if (start != string.length())
87 addToAccessControlAllowList(string, start, string.length() - 1, set);
88
89 return true;
90 }
91
parse(const ResourceResponse & response,String & errorDescription)92 bool CrossOriginPreflightResultCacheItem::parse(const ResourceResponse& response, String& errorDescription)
93 {
94 m_methods.clear();
95 if (!parseAccessControlAllowList(response.httpHeaderField("Access-Control-Allow-Methods"), m_methods)) {
96 errorDescription = "Cannot parse Access-Control-Allow-Methods response header field.";
97 return false;
98 }
99
100 m_headers.clear();
101 if (!parseAccessControlAllowList(response.httpHeaderField("Access-Control-Allow-Headers"), m_headers)) {
102 errorDescription = "Cannot parse Access-Control-Allow-Headers response header field.";
103 return false;
104 }
105
106 unsigned expiryDelta;
107 if (parseAccessControlMaxAge(response.httpHeaderField("Access-Control-Max-Age"), expiryDelta)) {
108 if (expiryDelta > maxPreflightCacheTimeoutSeconds)
109 expiryDelta = maxPreflightCacheTimeoutSeconds;
110 } else
111 expiryDelta = defaultPreflightCacheTimeoutSeconds;
112
113 m_absoluteExpiryTime = currentTime() + expiryDelta;
114 return true;
115 }
116
allowsCrossOriginMethod(const String & method,String & errorDescription) const117 bool CrossOriginPreflightResultCacheItem::allowsCrossOriginMethod(const String& method, String& errorDescription) const
118 {
119 if (m_methods.contains(method) || isOnAccessControlSimpleRequestMethodWhitelist(method))
120 return true;
121
122 errorDescription = "Method " + method + " is not allowed by Access-Control-Allow-Methods.";
123 return false;
124 }
125
allowsCrossOriginHeaders(const HTTPHeaderMap & requestHeaders,String & errorDescription) const126 bool CrossOriginPreflightResultCacheItem::allowsCrossOriginHeaders(const HTTPHeaderMap& requestHeaders, String& errorDescription) const
127 {
128 HTTPHeaderMap::const_iterator end = requestHeaders.end();
129 for (HTTPHeaderMap::const_iterator it = requestHeaders.begin(); it != end; ++it) {
130 if (!m_headers.contains(it->first) && !isOnAccessControlSimpleRequestHeaderWhitelist(it->first, it->second)) {
131 errorDescription = "Request header field " + it->first.string() + " is not allowed by Access-Control-Allow-Headers.";
132 return false;
133 }
134 }
135 return true;
136 }
137
allowsRequest(bool includeCredentials,const String & method,const HTTPHeaderMap & requestHeaders) const138 bool CrossOriginPreflightResultCacheItem::allowsRequest(bool includeCredentials, const String& method, const HTTPHeaderMap& requestHeaders) const
139 {
140 String ignoredExplanation;
141 if (m_absoluteExpiryTime < currentTime())
142 return false;
143 if (includeCredentials && !m_credentials)
144 return false;
145 if (!allowsCrossOriginMethod(method, ignoredExplanation))
146 return false;
147 if (!allowsCrossOriginHeaders(requestHeaders, ignoredExplanation))
148 return false;
149 return true;
150 }
151
shared()152 CrossOriginPreflightResultCache& CrossOriginPreflightResultCache::shared()
153 {
154 DEFINE_STATIC_LOCAL(CrossOriginPreflightResultCache, cache, ());
155 ASSERT(isMainThread());
156 return cache;
157 }
158
appendEntry(const String & origin,const KURL & url,PassOwnPtr<CrossOriginPreflightResultCacheItem> preflightResult)159 void CrossOriginPreflightResultCache::appendEntry(const String& origin, const KURL& url, PassOwnPtr<CrossOriginPreflightResultCacheItem> preflightResult)
160 {
161 ASSERT(isMainThread());
162 CrossOriginPreflightResultCacheItem* resultPtr = preflightResult.leakPtr();
163 pair<CrossOriginPreflightResultHashMap::iterator, bool> addResult = m_preflightHashMap.add(make_pair(origin, url), resultPtr);
164 if (!addResult.second) {
165 // FIXME: We need to delete the old value before replacing with the new one.
166 addResult.first->second = resultPtr;
167 }
168 }
169
canSkipPreflight(const String & origin,const KURL & url,bool includeCredentials,const String & method,const HTTPHeaderMap & requestHeaders)170 bool CrossOriginPreflightResultCache::canSkipPreflight(const String& origin, const KURL& url, bool includeCredentials, const String& method, const HTTPHeaderMap& requestHeaders)
171 {
172 ASSERT(isMainThread());
173 CrossOriginPreflightResultHashMap::iterator cacheIt = m_preflightHashMap.find(std::make_pair(origin, url));
174 if (cacheIt == m_preflightHashMap.end())
175 return false;
176
177 if (cacheIt->second->allowsRequest(includeCredentials, method, requestHeaders))
178 return true;
179
180 delete cacheIt->second;
181 m_preflightHashMap.remove(cacheIt);
182 return false;
183 }
184
empty()185 void CrossOriginPreflightResultCache::empty()
186 {
187 ASSERT(isMainThread());
188 deleteAllValues(m_preflightHashMap);
189 m_preflightHashMap.clear();
190 }
191
192 } // namespace WebCore
193