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
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)) != 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
parse(const ResourceResponse & response,String & errorDescription)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
allowsCrossOriginMethod(const String & method,String & errorDescription) const115 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
allowsCrossOriginHeaders(const HTTPHeaderMap & requestHeaders,String & errorDescription) const124 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
allowsRequest(StoredCredentials includeCredentials,const String & method,const HTTPHeaderMap & requestHeaders) const136 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
shared()150 CrossOriginPreflightResultCache& CrossOriginPreflightResultCache::shared()
151 {
152 DEFINE_STATIC_LOCAL(CrossOriginPreflightResultCache, cache, ());
153 ASSERT(isMainThread());
154 return cache;
155 }
156
appendEntry(const String & origin,const KURL & url,PassOwnPtr<CrossOriginPreflightResultCacheItem> preflightResult)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
canSkipPreflight(const String & origin,const KURL & url,StoredCredentials includeCredentials,const String & method,const HTTPHeaderMap & requestHeaders)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
empty()177 void CrossOriginPreflightResultCache::empty()
178 {
179 ASSERT(isMainThread());
180 m_preflightHashMap.clear();
181 }
182
183 } // namespace WebCore
184