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
parseAccessControlMaxAge(const String & string,unsigned & expiryDelta)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>
addToAccessControlAllowList(const String & string,unsigned start,unsigned end,HashSet<String,HashType> & set)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>
parseAccessControlAllowList(const String & string,HashSet<String,HashType> & set)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
parse(const ResourceResponse & response,String & errorDescription)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.";
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.";
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
allowsCrossOriginMethod(const String & method,String & errorDescription) const114 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.";
120 return false;
121 }
122
allowsCrossOriginHeaders(const HTTPHeaderMap & requestHeaders,String & errorDescription) const123 bool CrossOriginPreflightResultCacheItem::allowsCrossOriginHeaders(const HTTPHeaderMap& requestHeaders, String& errorDescription) const
124 {
125 HTTPHeaderMap::const_iterator end = requestHeaders.end();
126 for (HTTPHeaderMap::const_iterator it = requestHeaders.begin(); it != end; ++it) {
127 if (!m_headers.contains(it->key) && !FetchUtils::isSimpleHeader(it->key, it->value) && !FetchUtils::isForbiddenHeaderName(it->key)) {
128 errorDescription = "Request header field " + it->key.string() + " is not allowed by Access-Control-Allow-Headers.";
129 return false;
130 }
131 }
132 return true;
133 }
134
allowsRequest(StoredCredentials includeCredentials,const String & method,const HTTPHeaderMap & requestHeaders) const135 bool CrossOriginPreflightResultCacheItem::allowsRequest(StoredCredentials includeCredentials, const String& method, const HTTPHeaderMap& requestHeaders) const
136 {
137 String ignoredExplanation;
138 if (m_absoluteExpiryTime < currentTime())
139 return false;
140 if (includeCredentials == AllowStoredCredentials && m_credentials == DoNotAllowStoredCredentials)
141 return false;
142 if (!allowsCrossOriginMethod(method, ignoredExplanation))
143 return false;
144 if (!allowsCrossOriginHeaders(requestHeaders, ignoredExplanation))
145 return false;
146 return true;
147 }
148
shared()149 CrossOriginPreflightResultCache& CrossOriginPreflightResultCache::shared()
150 {
151 DEFINE_STATIC_LOCAL(CrossOriginPreflightResultCache, cache, ());
152 ASSERT(isMainThread());
153 return cache;
154 }
155
appendEntry(const String & origin,const KURL & url,PassOwnPtr<CrossOriginPreflightResultCacheItem> preflightResult)156 void CrossOriginPreflightResultCache::appendEntry(const String& origin, const KURL& url, PassOwnPtr<CrossOriginPreflightResultCacheItem> preflightResult)
157 {
158 ASSERT(isMainThread());
159 m_preflightHashMap.set(std::make_pair(origin, url), preflightResult);
160 }
161
canSkipPreflight(const String & origin,const KURL & url,StoredCredentials includeCredentials,const String & method,const HTTPHeaderMap & requestHeaders)162 bool CrossOriginPreflightResultCache::canSkipPreflight(const String& origin, const KURL& url, StoredCredentials includeCredentials, const String& method, const HTTPHeaderMap& requestHeaders)
163 {
164 ASSERT(isMainThread());
165 CrossOriginPreflightResultHashMap::iterator cacheIt = m_preflightHashMap.find(std::make_pair(origin, url));
166 if (cacheIt == m_preflightHashMap.end())
167 return false;
168
169 if (cacheIt->value->allowsRequest(includeCredentials, method, requestHeaders))
170 return true;
171
172 m_preflightHashMap.remove(cacheIt);
173 return false;
174 }
175
176 } // namespace blink
177