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content / browser / loader / prefetch_url_loader_service_context.cc [blame]
// Copyright 2023 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "content/browser/loader/prefetch_url_loader_service_context.h"
#include "content/browser/loader/prefetch_url_loader.h"
#include "content/browser/renderer_host/frame_tree_node.h"
#include "content/browser/renderer_host/render_frame_host_impl.h"
#include "content/browser/web_package/prefetched_signed_exchange_cache.h"
#include "content/public/browser/content_browser_client.h"
#include "content/public/browser/url_loader_throttles.h"
#include "content/public/browser/web_contents.h"
#include "content/public/common/content_client.h"
#include "third_party/blink/public/common/loader/url_loader_throttle.h"
#include "third_party/blink/public/common/renderer_preferences/renderer_preferences.h"
namespace content {
PrefetchURLLoaderServiceContext::PrefetchURLLoaderServiceContext(
BrowserContext* browser_context,
mojo::ReceiverSet<network::mojom::URLLoaderFactory,
scoped_refptr<BindContext>>& loader_factory_receivers)
: browser_context_(browser_context),
loader_factory_receivers_(loader_factory_receivers) {
DCHECK_CURRENTLY_ON(BrowserThread::UI);
accept_langs_ =
GetContentClient()->browser()->GetAcceptLangs(browser_context);
// Create a RendererPreferenceWatcher to observe updates in the preferences.
GetContentClient()->browser()->RegisterRendererPreferenceWatcher(
browser_context, preference_watcher_receiver_.BindNewPipeAndPassRemote());
}
void PrefetchURLLoaderServiceContext::CreatePrefetchLoaderAndStart(
mojo::PendingReceiver<network::mojom::URLLoader> receiver,
int32_t request_id,
uint32_t options,
const network::ResourceRequest& resource_request_in,
mojo::PendingRemote<network::mojom::URLLoaderClient> client,
const net::MutableNetworkTrafficAnnotationTag& traffic_annotation) {
CHECK(IsPrefetchRequest(resource_request_in));
// Make a copy of |resource_request_in|, because we may need to modify the
// request.
network::ResourceRequest resource_request = resource_request_in;
BindContext& current_context = *current_bind_context();
if (!current_context.render_frame_host) {
mojo::Remote<network::mojom::URLLoaderClient>(std::move(client))
->OnComplete(network::URLLoaderCompletionStatus(net::ERR_ABORTED));
return;
}
scoped_refptr<network::SharedURLLoaderFactory> network_loader_factory_to_use =
current_context.factory;
// The request must not already have its `trusted_params` initialized.
if (resource_request.trusted_params) {
loader_factory_receivers_->ReportBadMessage(
"Prefetch/CreatePrefetchLoaderAndStart: trusted params");
mojo::Remote<network::mojom::URLLoaderClient>(std::move(client))
->OnComplete(
network::URLLoaderCompletionStatus(net::ERR_INVALID_ARGUMENT));
return;
}
if (resource_request.load_flags &
net::LOAD_RESTRICTED_PREFETCH_FOR_MAIN_FRAME) {
CHECK(!resource_request.recursive_prefetch_token);
// The renderer has marked this prefetch as restricted, meaning it is a
// cross-origin prefetch intended for top-level navigation reuse. We must
// verify that the request meets the necessary security requirements, and
// populate `resource_request`'s IsolationInfo appropriately.
EnsureCrossOriginFactory();
DCHECK(current_context.cross_origin_factory);
// An invalid request could indicate a compromised renderer
// inappropriately modifying the request, so we immediately complete it
// with an error.
if (!IsValidCrossOriginPrefetch(resource_request)) {
mojo::Remote<network::mojom::URLLoaderClient>(std::move(client))
->OnComplete(
network::URLLoaderCompletionStatus(net::ERR_INVALID_ARGUMENT));
return;
}
// Cross-site prefetches shouldn't include SameSite cookies.
resource_request.site_for_cookies = net::SiteForCookies();
// Attach the fenced frame nonce to the request's IsolationInfo. If the
// nonce is marked revoked for untrusted network access, the request will
// either not be created due to the check in
// `CorsURLLoaderFactory::CreateLoaderAndStart` or cancelled due to the
// check `CancelRequestIfNonceMatchesAndUrlNotExempted`.
// TODO(crbug.com/349978810): Attach credentialless iframe nonce.
std::optional<base::UnguessableToken> fenced_frame_nonce =
current_context.render_frame_host->frame_tree_node()
->GetFencedFrameNonce();
// Use the trusted cross-origin prefetch loader factory, and set the
// request's IsolationInfo suitable for the cross-origin prefetch.
network_loader_factory_to_use = current_context.cross_origin_factory;
url::Origin destination_origin = url::Origin::Create(resource_request.url);
resource_request.trusted_params = network::ResourceRequest::TrustedParams();
resource_request.trusted_params->isolation_info =
net::IsolationInfo::Create(net::IsolationInfo::RequestType::kMainFrame,
destination_origin, destination_origin,
net::SiteForCookies(),
/*nonce=*/fenced_frame_nonce);
} else if (resource_request.recursive_prefetch_token) {
// Recursive prefetch from a cross-origin main resource prefetch.
// TODO(crbug.com/40150754): Figure out why we're seeing this condition
// hold true in the field.
if (!current_context.cross_origin_factory) {
return;
}
// Resurrect the request's IsolationInfo from the current context's map,
// and use it for this request.
auto isolation_info_iterator =
current_context.prefetch_isolation_infos.find(
resource_request.recursive_prefetch_token.value());
// An unexpected token could indicate a compromised renderer trying to
// fetch a request in a special way. We'll cancel the request.
if (isolation_info_iterator ==
current_context.prefetch_isolation_infos.end()) {
mojo::Remote<network::mojom::URLLoaderClient>(std::move(client))
->OnComplete(
network::URLLoaderCompletionStatus(net::ERR_INVALID_ARGUMENT));
return;
}
// Cross-site prefetches shouldn't include SameSite cookies.
resource_request.site_for_cookies = net::SiteForCookies();
resource_request.trusted_params = network::ResourceRequest::TrustedParams();
resource_request.trusted_params->isolation_info =
isolation_info_iterator->second;
network_loader_factory_to_use = current_context.cross_origin_factory;
}
if (prefetch_load_callback_for_testing_) {
prefetch_load_callback_for_testing_.Run();
}
scoped_refptr<PrefetchedSignedExchangeCache>
prefetched_signed_exchange_cache =
current_context.prefetched_signed_exchange_cache;
// base::Unretained is safe here since |this| owns the loader.
auto loader = std::make_unique<PrefetchURLLoader>(
request_id, options, current_context.frame_tree_node_id, resource_request,
resource_request.trusted_params
? resource_request.trusted_params->isolation_info
.network_anonymization_key()
: current_context.render_frame_host->GetIsolationInfoForSubresources()
.network_anonymization_key(),
std::move(client), traffic_annotation,
std::move(network_loader_factory_to_use),
base::BindRepeating(
&PrefetchURLLoaderServiceContext::CreateURLLoaderThrottles,
base::Unretained(this), resource_request,
current_context.frame_tree_node_id),
browser_context_, std::move(prefetched_signed_exchange_cache),
accept_langs_,
base::BindOnce(
&PrefetchURLLoaderServiceContext::GenerateRecursivePrefetchToken,
base::Unretained(this),
current_context.weak_ptr_factory.GetWeakPtr()));
auto* raw_loader = loader.get();
prefetch_loader_receivers_.Add(raw_loader, std::move(receiver),
std::move(loader));
}
PrefetchURLLoaderServiceContext::~PrefetchURLLoaderServiceContext() = default;
// This method is used to determine whether it is safe to set the IsolationInfo
// of a cross-origin prefetch request coming from the renderer, so that it can
// be cached correctly.
bool PrefetchURLLoaderServiceContext::IsValidCrossOriginPrefetch(
const network::ResourceRequest& resource_request) {
// All fetches need to have an associated request_initiator.
if (!resource_request.request_initiator) {
loader_factory_receivers_->ReportBadMessage(
"Prefetch/IsValidCrossOrigin: no request_initiator");
return false;
}
// The request is expected to be cross-origin. Same-origin prefetches do not
// need a special IsolationInfo, and therefore must not be marked for
// restricted use.
if (resource_request.request_initiator->IsSameOriginWith(
resource_request.url)) {
loader_factory_receivers_->ReportBadMessage(
"Prefetch/IsValidCrossOrigin: same-origin");
return false;
}
// The request initiator has to match the request_initiator_origin_lock - it
// has to be the same origin as the last committed origin in the frame.
const BindContext& current_context = *current_bind_context();
// Presence of |render_frame_host| is guaranteed by the caller - the caller
// calls earlier EnsureCrossOriginFactory which has the same DCHECK.
DCHECK(current_context.render_frame_host);
if (!resource_request.request_initiator->opaque() &&
resource_request.request_initiator.value() !=
current_context.render_frame_host->GetLastCommittedOrigin()) {
loader_factory_receivers_->ReportBadMessage(
"Prefetch/IsValidCrossOrigin: frame origin mismatch");
return false;
}
// If the PrefetchPrivacyChanges feature is enabled, the request's redirect
// mode must be |kError|.
if (base::FeatureList::IsEnabled(blink::features::kPrefetchPrivacyChanges) &&
resource_request.redirect_mode != network::mojom::RedirectMode::kError) {
loader_factory_receivers_->ReportBadMessage(
"Prefetch/IsValidCrossOrigin: wrong redirect mode");
return false;
}
// This prefetch request must not be able to reuse restricted prefetches from
// the prefetch cache. This is because it is possible that another origin
// prefetched the same resource, which should only be reused for top-level
// navigations.
if (resource_request.load_flags &
net::LOAD_CAN_USE_RESTRICTED_PREFETCH_FOR_MAIN_FRAME) {
loader_factory_receivers_->ReportBadMessage(
"Prefetch/IsValidCrossOrigin: can use restricted prefetch");
return false;
}
return true;
}
void PrefetchURLLoaderServiceContext::EnsureCrossOriginFactory() {
BindContext& current_context = *current_bind_context();
// If the factory has already been created, don't re-create it.
if (current_context.cross_origin_factory) {
return;
}
DCHECK(current_context.render_frame_host);
std::unique_ptr<network::PendingSharedURLLoaderFactory> factories =
current_context.render_frame_host
->CreateCrossOriginPrefetchLoaderFactoryBundle();
current_context.cross_origin_factory =
network::SharedURLLoaderFactory::Create(std::move(factories));
}
void PrefetchURLLoaderServiceContext::NotifyUpdate(
const blink::RendererPreferences& new_prefs) {
SetAcceptLanguages(new_prefs.accept_languages);
}
base::UnguessableToken
PrefetchURLLoaderServiceContext::GenerateRecursivePrefetchToken(
base::WeakPtr<BindContext> current_context,
const network::ResourceRequest& request) {
// If the relevant frame has gone away before this method is called
// asynchronously, we cannot generate and store a {token, IsolationInfo} pair
// in the frame's `prefetch_isolation_infos` map, so we'll create and return a
// dummy token that will not get used.
if (!current_context) {
return base::UnguessableToken::Create();
}
// Attach the fenced frame nonce to the request's IsolationInfo. If the nonce
// is marked revoked for untrusted network access, the request will either not
// be created due to the check in `CorsURLLoaderFactory::CreateLoaderAndStart`
// or cancelled due to the check
// `CancelRequestIfNonceMatchesAndUrlNotExempted`.
// TODO(crbug.com/349978810): Attach credentialless iframe nonce.
std::optional<base::UnguessableToken> fenced_frame_nonce =
current_context->render_frame_host
? current_context->render_frame_host->frame_tree_node()
->GetFencedFrameNonce()
: std::nullopt;
// Create IsolationInfo.
url::Origin destination_origin = url::Origin::Create(request.url);
net::IsolationInfo preload_isolation_info = net::IsolationInfo::Create(
net::IsolationInfo::RequestType::kOther, destination_origin,
destination_origin, net::SiteForCookies(), /*nonce=*/fenced_frame_nonce);
// Generate token.
base::UnguessableToken return_token = base::UnguessableToken::Create();
// Associate the two, and return the token.
current_context->prefetch_isolation_infos.insert(
{return_token, preload_isolation_info});
return return_token;
}
std::vector<std::unique_ptr<blink::URLLoaderThrottle>>
PrefetchURLLoaderServiceContext::CreateURLLoaderThrottles(
const network::ResourceRequest& request,
FrameTreeNodeId frame_tree_node_id) {
return CreateContentBrowserURLLoaderThrottles(
request, browser_context_,
base::BindRepeating(&WebContents::FromFrameTreeNodeId,
frame_tree_node_id),
nullptr /* navigation_ui_data */, frame_tree_node_id,
/*navigation_id=*/std::nullopt);
}
} // namespace content