1/*
2 * Copyright (C) 2018 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 INC. AND ITS CONTRIBUTORS ``AS IS'' AND ANY
14 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
15 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
16 * DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS BE LIABLE FOR ANY
17 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
18 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
19 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
20 * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
21 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
22 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
23 */
24
25#include "config.h"
26#include "ReferrerPolicy.h"
27
28#include "HTTPParsers.h"
29#include <wtf/Optional.h>
30
31namespace WebCore {
32
33enum class ShouldParseLegacyKeywords { No, Yes };
34
35static Optional<ReferrerPolicy> parseReferrerPolicyToken(StringView policy, ShouldParseLegacyKeywords shouldParseLegacyKeywords)
36{
37 // "never" / "default" / "always" are legacy keywords that we support and still defined in the HTML specification:
38 // https://html.spec.whatwg.org/#meta-referrer
39 if (shouldParseLegacyKeywords == ShouldParseLegacyKeywords::Yes) {
40 if (equalLettersIgnoringASCIICase(policy, "never"))
41 return ReferrerPolicy::NoReferrer;
42 if (equalLettersIgnoringASCIICase(policy, "always"))
43 return ReferrerPolicy::UnsafeUrl;
44 if (equalLettersIgnoringASCIICase(policy, "default"))
45 return ReferrerPolicy::NoReferrerWhenDowngrade;
46 }
47
48 if (equalLettersIgnoringASCIICase(policy, "no-referrer"))
49 return ReferrerPolicy::NoReferrer;
50 if (equalLettersIgnoringASCIICase(policy, "unsafe-url"))
51 return ReferrerPolicy::UnsafeUrl;
52 if (equalLettersIgnoringASCIICase(policy, "origin"))
53 return ReferrerPolicy::Origin;
54 if (equalLettersIgnoringASCIICase(policy, "origin-when-cross-origin"))
55 return ReferrerPolicy::OriginWhenCrossOrigin;
56 if (equalLettersIgnoringASCIICase(policy, "same-origin"))
57 return ReferrerPolicy::SameOrigin;
58 if (equalLettersIgnoringASCIICase(policy, "strict-origin"))
59 return ReferrerPolicy::StrictOrigin;
60 if (equalLettersIgnoringASCIICase(policy, "strict-origin-when-cross-origin"))
61 return ReferrerPolicy::StrictOriginWhenCrossOrigin;
62 if (equalLettersIgnoringASCIICase(policy, "no-referrer-when-downgrade"))
63 return ReferrerPolicy::NoReferrerWhenDowngrade;
64 if (!policy.isNull() && policy.isEmpty())
65 return ReferrerPolicy::EmptyString;
66
67 return WTF::nullopt;
68}
69
70Optional<ReferrerPolicy> parseReferrerPolicy(StringView policyString, ReferrerPolicySource source)
71{
72 switch (source) {
73 case ReferrerPolicySource::HTTPHeader: {
74 // Implementing https://www.w3.org/TR/2017/CR-referrer-policy-20170126/#parse-referrer-policy-from-header.
75 Optional<ReferrerPolicy> result;
76 for (auto tokenView : policyString.split(',')) {
77 auto token = parseReferrerPolicyToken(stripLeadingAndTrailingHTTPSpaces(tokenView), ShouldParseLegacyKeywords::No);
78 if (token && token.value() != ReferrerPolicy::EmptyString)
79 result = token.value();
80 }
81 return result;
82 }
83 case ReferrerPolicySource::MetaTag:
84 return parseReferrerPolicyToken(policyString, ShouldParseLegacyKeywords::Yes);
85 case ReferrerPolicySource::ReferrerPolicyAttribute:
86 return parseReferrerPolicyToken(policyString, ShouldParseLegacyKeywords::No);
87 }
88 ASSERT_NOT_REACHED();
89 return WTF::nullopt;
90}
91
92} // namespace WebCore
93