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- /*
- * Copyright (c) 2022, Linus Groh <linusg@serenityos.org>
- * Copyright (c) 2024, Jamie Mansfield <jmansfield@cadixdev.org>
- *
- * SPDX-License-Identifier: BSD-2-Clause
- */
- #include <LibURL/URL.h>
- #include <LibWeb/DOM/Document.h>
- #include <LibWeb/DOMURL/DOMURL.h>
- #include <LibWeb/Fetch/Infrastructure/HTTP/Requests.h>
- #include <LibWeb/Fetch/Infrastructure/URL.h>
- #include <LibWeb/HTML/Window.h>
- #include <LibWeb/ReferrerPolicy/AbstractOperations.h>
- #include <LibWeb/ReferrerPolicy/ReferrerPolicy.h>
- #include <LibWeb/SecureContexts/AbstractOperations.h>
- namespace Web::ReferrerPolicy {
- // https://w3c.github.io/webappsec-referrer-policy/#parse-referrer-policy-from-header
- ReferrerPolicy parse_a_referrer_policy_from_a_referrer_policy_header(Fetch::Infrastructure::Response const& response)
- {
- // 1. Let policy-tokens be the result of extracting header list values given `Referrer-Policy` and response’s header list.
- auto policy_tokens_or_failure = Fetch::Infrastructure::extract_header_list_values("Referrer-Policy"sv.bytes(), response.header_list());
- auto policy_tokens = policy_tokens_or_failure.has<Vector<ByteBuffer>>() ? policy_tokens_or_failure.get<Vector<ByteBuffer>>() : Vector<ByteBuffer> {};
- // 2. Let policy be the empty string.
- auto policy = ReferrerPolicy::EmptyString;
- // 3. For each token in policy-tokens, if token is a referrer policy and token is not the empty string, then set policy to token.
- for (auto token : policy_tokens) {
- auto referrer_policy = from_string(token);
- if (referrer_policy.has_value() && referrer_policy.value() != ReferrerPolicy::EmptyString)
- policy = referrer_policy.release_value();
- }
- // 4. Return policy.
- return policy;
- }
- // https://w3c.github.io/webappsec-referrer-policy/#set-requests-referrer-policy-on-redirect
- void set_request_referrer_policy_on_redirect(Fetch::Infrastructure::Request& request, Fetch::Infrastructure::Response const& response)
- {
- // 1. Let policy be the result of executing § 8.1 Parse a referrer policy from a Referrer-Policy header on
- // actualResponse.
- auto policy = parse_a_referrer_policy_from_a_referrer_policy_header(response);
- // 2. If policy is not the empty string, then set request’s referrer policy to policy.
- if (policy != ReferrerPolicy::EmptyString)
- request.set_referrer_policy(policy);
- }
- // https://w3c.github.io/webappsec-referrer-policy/#determine-requests-referrer
- Optional<URL::URL> determine_requests_referrer(Fetch::Infrastructure::Request const& request)
- {
- // 1. Let policy be request’s referrer policy.
- auto const& policy = request.referrer_policy();
- // 2. Let environment be request’s client.
- auto environment = request.client();
- // 3. Switch on request’s referrer:
- auto referrer_source = request.referrer().visit(
- // "client"
- [&](Fetch::Infrastructure::Request::Referrer referrer) -> Optional<URL::URL> {
- // Note: If request’s referrer is "no-referrer", Fetch will not call into this algorithm.
- VERIFY(referrer == Fetch::Infrastructure::Request::Referrer::Client);
- // FIXME: Add a const global_object() getter to ESO
- auto& global_object = const_cast<HTML::EnvironmentSettingsObject&>(*environment).global_object();
- // 1. If environment’s global object is a Window object, then
- if (is<HTML::Window>(global_object)) {
- // 1. Let document be the associated Document of environment’s global object.
- auto const& document = static_cast<HTML::Window const&>(global_object).associated_document();
- // 2. If document’s origin is an opaque origin, return no referrer.
- if (document.origin().is_opaque())
- return {};
- // FIXME: 3. While document is an iframe srcdoc document, let document be document’s browsing context’s
- // browsing context container’s node document.
- // 4. Let referrerSource be document’s URL.
- return document.url();
- }
- // 2. Otherwise, let referrerSource be environment’s creation URL.
- else {
- return environment->creation_url;
- }
- },
- // a URL
- [&](URL::URL const& url) -> Optional<URL::URL> {
- // Let referrerSource be request’s referrer.
- return url;
- });
- // NOTE: This only happens in step 1.2. of the "client" case above.
- if (!referrer_source.has_value())
- return {};
- // 4. Let request’s referrerURL be the result of stripping referrerSource for use as a referrer.
- auto referrer_url = strip_url_for_use_as_referrer(referrer_source);
- // 5. Let referrerOrigin be the result of stripping referrerSource for use as a referrer, with the origin-only flag
- // set to true.
- auto referrer_origin = strip_url_for_use_as_referrer(referrer_source, OriginOnly::Yes);
- // 6. If the result of serializing referrerURL is a string whose length is greater than 4096, set referrerURL to
- // referrerOrigin.
- if (referrer_url.has_value() && referrer_url.value().serialize().length() > 4096)
- referrer_url = referrer_origin;
- // 7. The user agent MAY alter referrerURL or referrerOrigin at this point to enforce arbitrary policy
- // considerations in the interests of minimizing data leakage. For example, the user agent could strip the URL
- // down to an origin, modify its host, replace it with an empty string, etc.
- // 8. Execute the statements corresponding to the value of policy:
- // Note: If request’s referrer policy is the empty string, Fetch will not call into this algorithm.
- VERIFY(policy != ReferrerPolicy::EmptyString);
- switch (policy) {
- // "no-referrer"
- case ReferrerPolicy::NoReferrer:
- // Return no referrer
- return {};
- // "origin"
- case ReferrerPolicy::Origin:
- // Return referrerOrigin
- return referrer_origin;
- // "unsafe-url"
- case ReferrerPolicy::UnsafeURL:
- // Return referrerURL.
- return referrer_url;
- // "strict-origin"
- case ReferrerPolicy::StrictOrigin:
- // 1. If referrerURL is a potentially trustworthy URL and request’s current URL is not a potentially
- // trustworthy URL, then return no referrer.
- if (referrer_url.has_value()
- && SecureContexts::is_url_potentially_trustworthy(*referrer_url) == SecureContexts::Trustworthiness::PotentiallyTrustworthy
- && SecureContexts::is_url_potentially_trustworthy(request.current_url()) == SecureContexts::Trustworthiness::NotTrustworthy) {
- return {};
- }
- // 2. Return referrerOrigin.
- return referrer_origin;
- // "strict-origin-when-cross-origin"
- case ReferrerPolicy::StrictOriginWhenCrossOrigin:
- // 1. If the origin of referrerURL and the origin of request’s current URL are the same, then return
- // referrerURL.
- if (referrer_url.has_value() && referrer_url->origin().is_same_origin(request.current_url().origin()))
- return referrer_url;
- // 2. If referrerURL is a potentially trustworthy URL and request’s current URL is not a potentially
- // trustworthy URL, then return no referrer.
- if (referrer_url.has_value()
- && SecureContexts::is_url_potentially_trustworthy(*referrer_url) == SecureContexts::Trustworthiness::PotentiallyTrustworthy
- && SecureContexts::is_url_potentially_trustworthy(request.current_url()) == SecureContexts::Trustworthiness::NotTrustworthy) {
- return {};
- }
- // 3. Return referrerOrigin.
- return referrer_origin;
- // "same-origin"
- case ReferrerPolicy::SameOrigin:
- // 1. If the origin of referrerURL and the origin of request’s current URL are the same, then return
- // referrerURL.
- if (referrer_url.has_value()
- && referrer_url->origin().is_same_origin(request.current_url().origin())) {
- return referrer_url;
- }
- // 2. Return no referrer.
- return {};
- // "origin-when-cross-origin"
- case ReferrerPolicy::OriginWhenCrossOrigin:
- // 1. If the origin of referrerURL and the origin of request’s current URL are the same, then return
- // referrerURL.
- if (referrer_url.has_value()
- && referrer_url->origin().is_same_origin(request.current_url().origin())) {
- return referrer_url;
- }
- // 2. Return referrerOrigin.
- return referrer_origin;
- // "no-referrer-when-downgrade"
- case ReferrerPolicy::NoReferrerWhenDowngrade:
- // 1. If referrerURL is a potentially trustworthy URL and request’s current URL is not a potentially
- // trustworthy URL, then return no referrer.
- if (referrer_url.has_value()
- && SecureContexts::is_url_potentially_trustworthy(*referrer_url) == SecureContexts::Trustworthiness::PotentiallyTrustworthy
- && SecureContexts::is_url_potentially_trustworthy(request.current_url()) == SecureContexts::Trustworthiness::NotTrustworthy) {
- return {};
- }
- // 2. Return referrerURL.
- return referrer_url;
- default:
- VERIFY_NOT_REACHED();
- }
- }
- // https://w3c.github.io/webappsec-referrer-policy/#strip-url
- Optional<URL::URL> strip_url_for_use_as_referrer(Optional<URL::URL> url, OriginOnly origin_only)
- {
- // 1. If url is null, return no referrer.
- if (!url.has_value())
- return {};
- // 2. If url’s scheme is a local scheme, then return no referrer.
- if (Fetch::Infrastructure::LOCAL_SCHEMES.span().contains_slow(url->scheme()))
- return {};
- // 3. Set url’s username to the empty string.
- url->set_username(""sv);
- // 4. Set url’s password to the empty string.
- url->set_password(""sv);
- // 5. Set url’s fragment to null.
- url->set_fragment({});
- // 6. If the origin-only flag is true, then:
- if (origin_only == OriginOnly::Yes) {
- // 1. Set url’s path to « the empty string ».
- url->set_paths({ ""sv });
- // 2. Set url’s query to null.
- url->set_query({});
- }
- // 7. Return url.
- return url;
- }
- }
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