CrossOriginPreflightResultCache.cpp [plain text]
#include "config.h"
#include "CrossOriginPreflightResultCache.h"
#include "CrossOriginAccessControl.h"
#include "HTTPHeaderNames.h"
#include "HTTPParsers.h"
#include "ResourceResponse.h"
#include <wtf/MainThread.h>
#include <wtf/NeverDestroyed.h>
namespace WebCore {
static const auto defaultPreflightCacheTimeout = 5_s;
static const auto maxPreflightCacheTimeout = 600_s;
CrossOriginPreflightResultCache::CrossOriginPreflightResultCache()
{
}
static bool parseAccessControlMaxAge(const String& string, Seconds& expiryDelta)
{
bool ok = false;
expiryDelta = Seconds(static_cast<double>(string.toUIntStrict(&ok)));
return ok;
}
Expected<UniqueRef<CrossOriginPreflightResultCacheItem>, String> CrossOriginPreflightResultCacheItem::create(StoredCredentialsPolicy policy, const ResourceResponse& response)
{
auto methods = parseAccessControlAllowList(response.httpHeaderField(HTTPHeaderName::AccessControlAllowMethods));
if (!methods)
return makeUnexpected(makeString("Header Access-Control-Allow-Methods has an invalid value: ", response.httpHeaderField(HTTPHeaderName::AccessControlAllowMethods)));
auto headers = parseAccessControlAllowList<ASCIICaseInsensitiveHash>(response.httpHeaderField(HTTPHeaderName::AccessControlAllowHeaders));
if (!headers)
return makeUnexpected(makeString("Header Access-Control-Allow-Headers has an invalid value: ", response.httpHeaderField(HTTPHeaderName::AccessControlAllowHeaders)));
Seconds expiryDelta = 0_s;
if (parseAccessControlMaxAge(response.httpHeaderField(HTTPHeaderName::AccessControlMaxAge), expiryDelta)) {
if (expiryDelta > maxPreflightCacheTimeout)
expiryDelta = maxPreflightCacheTimeout;
} else
expiryDelta = defaultPreflightCacheTimeout;
return makeUniqueRef<CrossOriginPreflightResultCacheItem>(MonotonicTime::now() + expiryDelta, policy, WTFMove(*methods), WTFMove(*headers));
}
Optional<String> CrossOriginPreflightResultCacheItem::validateMethodAndHeaders(const String& method, const HTTPHeaderMap& requestHeaders) const
{
if (!allowsCrossOriginMethod(method, m_storedCredentialsPolicy))
return makeString("Method ", method, " is not allowed by Access-Control-Allow-Methods.");
if (auto badHeader = validateCrossOriginHeaders(requestHeaders, m_storedCredentialsPolicy))
return makeString("Request header field ", *badHeader, " is not allowed by Access-Control-Allow-Headers.");
return { };
}
bool CrossOriginPreflightResultCacheItem::allowsCrossOriginMethod(const String& method, StoredCredentialsPolicy storedCredentialsPolicy) const
{
return m_methods.contains(method) || (m_methods.contains("*") && storedCredentialsPolicy != StoredCredentialsPolicy::Use) || isOnAccessControlSimpleRequestMethodAllowlist(method);
}
Optional<String> CrossOriginPreflightResultCacheItem::validateCrossOriginHeaders(const HTTPHeaderMap& requestHeaders, StoredCredentialsPolicy storedCredentialsPolicy) const
{
bool validWildcard = m_headers.contains("*") && storedCredentialsPolicy != StoredCredentialsPolicy::Use;
for (const auto& header : requestHeaders) {
if (header.keyAsHTTPHeaderName && isCrossOriginSafeRequestHeader(header.keyAsHTTPHeaderName.value(), header.value))
continue;
if (!m_headers.contains(header.key) && !validWildcard)
return header.key;
}
return { };
}
bool CrossOriginPreflightResultCacheItem::allowsRequest(StoredCredentialsPolicy storedCredentialsPolicy, const String& method, const HTTPHeaderMap& requestHeaders) const
{
if (m_absoluteExpiryTime < MonotonicTime::now())
return false;
if (storedCredentialsPolicy == StoredCredentialsPolicy::Use && m_storedCredentialsPolicy == StoredCredentialsPolicy::DoNotUse)
return false;
if (!allowsCrossOriginMethod(method, storedCredentialsPolicy))
return false;
if (auto badHeader = validateCrossOriginHeaders(requestHeaders, storedCredentialsPolicy))
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, StoredCredentialsPolicy storedCredentialsPolicy, 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(storedCredentialsPolicy, method, requestHeaders))
return true;
m_preflightHashMap.remove(it);
return false;
}
void CrossOriginPreflightResultCache::clear()
{
ASSERT(isMainThread());
m_preflightHashMap.clear();
}
}