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/*
* Copyright (C) 2008, 2009 Apple Inc. All Rights Reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
* OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
*/
#include "config.h"
#include "CrossOriginPreflightResultCache.h"
#include "CrossOriginAccessControl.h"
#include "HTTPHeaderNames.h"
#include "ResourceResponse.h"
#include <wtf/MainThread.h>
#include <wtf/NeverDestroyed.h>
#include <wtf/StdLibExtras.h>
namespace WebCore {
// These values are at the discretion of the user agent.
static const auto defaultPreflightCacheTimeout = std::chrono::seconds(5);
static const auto maxPreflightCacheTimeout = std::chrono::seconds(600); // Should be short enough to minimize the risk of using a poisoned cache after switching to a secure network.
CrossOriginPreflightResultCache::CrossOriginPreflightResultCache()
{
}
static bool parseAccessControlMaxAge(const String& string, std::chrono::seconds& expiryDelta)
{
// FIXME: this will not do the correct thing for a number starting with a '+'
bool ok = false;
expiryDelta = std::chrono::seconds(string.toUIntStrict(&ok));
return ok;
}
template<class HashType>
static void addToAccessControlAllowList(const String& string, unsigned start, unsigned end, HashSet<String, HashType>& set)
{
StringImpl* stringImpl = string.impl();
if (!stringImpl)
return;
// Skip white space from start.
while (start <= end && isSpaceOrNewline((*stringImpl)[start]))
++start;
// only white space
if (start > end)
return;
// Skip white space from end.
while (end && isSpaceOrNewline((*stringImpl)[end]))
--end;
set.add(string.substring(start, end - start + 1));
}
template<class HashType>
static bool parseAccessControlAllowList(const String& string, HashSet<String, HashType>& set)
{
unsigned start = 0;
size_t end;
while ((end = string.find(',', start)) != notFound) {
if (start != end)
addToAccessControlAllowList(string, start, end - 1, set);
start = end + 1;
}
if (start != string.length())
addToAccessControlAllowList(string, start, string.length() - 1, set);
return true;
}
bool CrossOriginPreflightResultCacheItem::parse(const ResourceResponse& response, String& errorDescription)
{
m_methods.clear();
if (!parseAccessControlAllowList(response.httpHeaderField(HTTPHeaderName::AccessControlAllowMethods), m_methods)) {
errorDescription = "Cannot parse Access-Control-Allow-Methods response header field.";
return false;
}
m_headers.clear();
if (!parseAccessControlAllowList(response.httpHeaderField(HTTPHeaderName::AccessControlAllowHeaders), m_headers)) {
errorDescription = "Cannot parse Access-Control-Allow-Headers response header field.";
return false;
}
std::chrono::seconds expiryDelta;
if (parseAccessControlMaxAge(response.httpHeaderField(HTTPHeaderName::AccessControlMaxAge), expiryDelta)) {
if (expiryDelta > maxPreflightCacheTimeout)
expiryDelta = maxPreflightCacheTimeout;
} else
expiryDelta = defaultPreflightCacheTimeout;
m_absoluteExpiryTime = std::chrono::steady_clock::now() + expiryDelta;
return true;
}
bool CrossOriginPreflightResultCacheItem::allowsCrossOriginMethod(const String& method, String& errorDescription) const
{
if (m_methods.contains(method) || isOnAccessControlSimpleRequestMethodWhitelist(method))
return true;
errorDescription = "Method " + method + " is not allowed by Access-Control-Allow-Methods.";
return false;
}
bool CrossOriginPreflightResultCacheItem::allowsCrossOriginHeaders(const HTTPHeaderMap& requestHeaders, String& errorDescription) const
{
for (const auto& header : requestHeaders) {
if (header.keyAsHTTPHeaderName && isOnAccessControlSimpleRequestHeaderWhitelist(header.keyAsHTTPHeaderName.value(), header.value))
continue;
if (!m_headers.contains(header.key)) {
errorDescription = "Request header field " + header.key + " is not allowed by Access-Control-Allow-Headers.";
return false;
}
}
return true;
}
bool CrossOriginPreflightResultCacheItem::allowsRequest(StoredCredentials includeCredentials, const String& method, const HTTPHeaderMap& requestHeaders) const
{
String ignoredExplanation;
if (m_absoluteExpiryTime < std::chrono::steady_clock::now())
return false;
if (includeCredentials == AllowStoredCredentials && m_credentials == DoNotAllowStoredCredentials)
return false;
if (!allowsCrossOriginMethod(method, ignoredExplanation))
return false;
if (!allowsCrossOriginHeaders(requestHeaders, ignoredExplanation))
return false;
return true;
}
CrossOriginPreflightResultCache& CrossOriginPreflightResultCache::singleton()
{
ASSERT(isMainThread());
static NeverDestroyed<CrossOriginPreflightResultCache> cache;
return cache;
}
void CrossOriginPreflightResultCache::appendEntry(const String& origin, const URL& url, std::unique_ptr<CrossOriginPreflightResultCacheItem> preflightResult)
{
ASSERT(isMainThread());
m_preflightHashMap.set(std::make_pair(origin, url), WTFMove(preflightResult));
}
bool CrossOriginPreflightResultCache::canSkipPreflight(const String& origin, const URL& url, StoredCredentials includeCredentials, const String& method, const HTTPHeaderMap& requestHeaders)
{
ASSERT(isMainThread());
auto it = m_preflightHashMap.find(std::make_pair(origin, url));
if (it == m_preflightHashMap.end())
return false;
if (it->value->allowsRequest(includeCredentials, method, requestHeaders))
return true;
m_preflightHashMap.remove(it);
return false;
}
void CrossOriginPreflightResultCache::empty()
{
ASSERT(isMainThread());
m_preflightHashMap.clear();
}
} // namespace WebCore
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