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// Copyright 2014 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "content/public/common/referrer.h"
#include <atomic>
#include <string>
#include "base/numerics/safe_conversions.h"
#include "content/public/common/content_features.h"
#include "content/public/common/content_switches.h"
#include "mojo/public/cpp/bindings/enum_utils.h"
#include "net/base/features.h"
#include "services/network/public/cpp/features.h"
#include "services/network/public/cpp/resource_request.h"
#include "third_party/blink/public/mojom/referrer.mojom.h"
namespace content {
namespace {
// Using an atomic is necessary because this code is called from both the
// browser and the renderer (so that access is not on a single sequence when in
// single-process mode), and because it is called from multiple threads within
// the renderer.
bool ReadModifyWriteForceLegacyPolicyFlag(
base::Optional<bool> maybe_new_value) {
// Default to false in the browser process (it is not expected
// that the browser will be provided this switch).
// The value is propagated to other processes through the command line.
DCHECK(base::CommandLine::InitializedForCurrentProcess());
static std::atomic<bool> value(
base::CommandLine::ForCurrentProcess()->HasSwitch(
switches::kForceLegacyDefaultReferrerPolicy));
if (!maybe_new_value.has_value())
return value;
return value.exchange(*maybe_new_value);
}
} // namespace
Referrer::Referrer(const blink::mojom::Referrer& referrer)
: url(referrer.url), policy(referrer.policy) {}
// static
Referrer Referrer::SanitizeForRequest(const GURL& request,
const Referrer& referrer) {
blink::mojom::ReferrerPtr sanitized_referrer = SanitizeForRequest(
request, blink::mojom::Referrer(referrer.url, referrer.policy));
return Referrer(sanitized_referrer->url, sanitized_referrer->policy);
}
// static
blink::mojom::ReferrerPtr Referrer::SanitizeForRequest(
const GURL& request,
const blink::mojom::Referrer& referrer) {
blink::mojom::ReferrerPtr sanitized_referrer = blink::mojom::Referrer::New(
referrer.url.GetAsReferrer(), referrer.policy);
if (sanitized_referrer->policy == network::mojom::ReferrerPolicy::kDefault) {
sanitized_referrer->policy =
Referrer::NetReferrerPolicyToBlinkReferrerPolicy(
Referrer::GetDefaultReferrerPolicy());
}
if (sanitized_referrer->policy < network::mojom::ReferrerPolicy::kMinValue ||
sanitized_referrer->policy > network::mojom::ReferrerPolicy::kMaxValue) {
NOTREACHED();
sanitized_referrer->policy = network::mojom::ReferrerPolicy::kNever;
}
bool is_web_scheme = request.SchemeIsHTTPOrHTTPS() || request.IsAboutBlank();
if (!is_web_scheme || !sanitized_referrer->url.SchemeIsValidForReferrer()) {
sanitized_referrer->url = GURL();
return sanitized_referrer;
}
bool is_downgrade = sanitized_referrer->url.SchemeIsCryptographic() &&
!request.SchemeIsCryptographic();
switch (sanitized_referrer->policy) {
case network::mojom::ReferrerPolicy::kDefault:
NOTREACHED();
break;
case network::mojom::ReferrerPolicy::kNoReferrerWhenDowngrade:
if (is_downgrade)
sanitized_referrer->url = GURL();
break;
case network::mojom::ReferrerPolicy::kAlways:
break;
case network::mojom::ReferrerPolicy::kNever:
sanitized_referrer->url = GURL();
break;
case network::mojom::ReferrerPolicy::kOrigin:
sanitized_referrer->url = sanitized_referrer->url.GetOrigin();
break;
case network::mojom::ReferrerPolicy::kOriginWhenCrossOrigin:
if (request.GetOrigin() != sanitized_referrer->url.GetOrigin())
sanitized_referrer->url = sanitized_referrer->url.GetOrigin();
break;
case network::mojom::ReferrerPolicy::kStrictOrigin:
if (is_downgrade) {
sanitized_referrer->url = GURL();
} else {
sanitized_referrer->url = sanitized_referrer->url.GetOrigin();
}
break;
case network::mojom::ReferrerPolicy::kSameOrigin:
if (request.GetOrigin() != sanitized_referrer->url.GetOrigin())
sanitized_referrer->url = GURL();
break;
case network::mojom::ReferrerPolicy::kStrictOriginWhenCrossOrigin:
if (is_downgrade) {
sanitized_referrer->url = GURL();
} else if (request.GetOrigin() != sanitized_referrer->url.GetOrigin()) {
sanitized_referrer->url = sanitized_referrer->url.GetOrigin();
}
break;
}
// We limit the `referer` header to 4k: see step of
// https://w3c.github.io/webappsec-referrer-policy/#determine-requests-referrer
// and https://github.com/whatwg/fetch/issues/903.
if (sanitized_referrer->url.spec().length() > 4096 ||
(base::FeatureList::IsEnabled(
network::features::kCapReferrerToOriginOnCrossOrigin) &&
!url::Origin::Create(sanitized_referrer->url)
.IsSameOriginWith(url::Origin::Create(request)))) {
sanitized_referrer->url = sanitized_referrer->url.GetOrigin();
}
return sanitized_referrer;
}
// static
url::Origin Referrer::SanitizeOriginForRequest(
const GURL& request,
const url::Origin& initiator,
network::mojom::ReferrerPolicy policy) {
Referrer fake_referrer(initiator.GetURL(), policy);
Referrer sanitizied_referrer = SanitizeForRequest(request, fake_referrer);
return url::Origin::Create(sanitizied_referrer.url);
}
// static
net::URLRequest::ReferrerPolicy Referrer::ReferrerPolicyForUrlRequest(
network::mojom::ReferrerPolicy referrer_policy) {
if (referrer_policy == network::mojom::ReferrerPolicy::kDefault) {
return GetDefaultReferrerPolicy();
}
return network::ReferrerPolicyForUrlRequest(referrer_policy);
}
// static
network::mojom::ReferrerPolicy Referrer::NetReferrerPolicyToBlinkReferrerPolicy(
net::URLRequest::ReferrerPolicy net_policy) {
switch (net_policy) {
case net::URLRequest::CLEAR_REFERRER_ON_TRANSITION_FROM_SECURE_TO_INSECURE:
return network::mojom::ReferrerPolicy::kNoReferrerWhenDowngrade;
case net::URLRequest::
REDUCE_REFERRER_GRANULARITY_ON_TRANSITION_CROSS_ORIGIN:
return network::mojom::ReferrerPolicy::kStrictOriginWhenCrossOrigin;
case net::URLRequest::ORIGIN_ONLY_ON_TRANSITION_CROSS_ORIGIN:
return network::mojom::ReferrerPolicy::kOriginWhenCrossOrigin;
case net::URLRequest::NEVER_CLEAR_REFERRER:
return network::mojom::ReferrerPolicy::kAlways;
case net::URLRequest::ORIGIN:
return network::mojom::ReferrerPolicy::kOrigin;
case net::URLRequest::CLEAR_REFERRER_ON_TRANSITION_CROSS_ORIGIN:
return network::mojom::ReferrerPolicy::kSameOrigin;
case net::URLRequest::ORIGIN_CLEAR_ON_TRANSITION_FROM_SECURE_TO_INSECURE:
return network::mojom::ReferrerPolicy::kStrictOrigin;
case net::URLRequest::NO_REFERRER:
return network::mojom::ReferrerPolicy::kNever;
}
NOTREACHED();
return network::mojom::ReferrerPolicy::kDefault;
}
// static
net::URLRequest::ReferrerPolicy Referrer::GetDefaultReferrerPolicy() {
// The ReducedReferrerGranularity feature sets the default referrer
// policy to strict-origin-when-cross-origin unless forbidden
// by the "force legacy policy" global.
// TODO(M82, crbug.com/1016541) Once the pertinent enterprise policy has
// been removed, update this to remove the global.
// Short-circuit to avoid acquiring the lock unless necessary.
if (!base::FeatureList::IsEnabled(features::kReducedReferrerGranularity))
return net::URLRequest::
CLEAR_REFERRER_ON_TRANSITION_FROM_SECURE_TO_INSECURE;
return ShouldForceLegacyDefaultReferrerPolicy()
? net::URLRequest::
CLEAR_REFERRER_ON_TRANSITION_FROM_SECURE_TO_INSECURE
: net::URLRequest::
REDUCE_REFERRER_GRANULARITY_ON_TRANSITION_CROSS_ORIGIN;
}
// static
void Referrer::SetForceLegacyDefaultReferrerPolicy(bool force) {
ReadModifyWriteForceLegacyPolicyFlag(force);
}
// static
bool Referrer::ShouldForceLegacyDefaultReferrerPolicy() {
return ReadModifyWriteForceLegacyPolicyFlag(base::nullopt);
}
// static
network::mojom::ReferrerPolicy Referrer::ConvertToPolicy(int32_t policy) {
return mojo::ConvertIntToMojoEnum<network::mojom::ReferrerPolicy>(policy)
.value_or(network::mojom::ReferrerPolicy::kDefault);
}
} // namespace content
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