tor-browser

EarlyHintsService.cpp (5732B)

---

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set sw=2 ts=8 et tw=80 : */

/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "EarlyHintsService.h"
#include "EarlyHintPreconnect.h"
#include "EarlyHintPreloader.h"
#include "mozilla/dom/LinkStyle.h"
#include "mozilla/PreloadHashKey.h"
#include "mozilla/StoragePrincipalHelper.h"
#include "nsContentUtils.h"
#include "nsIChannel.h"
#include "nsICookieJarSettings.h"
#include "nsILoadInfo.h"
#include "nsIPrincipal.h"
#include "nsNetUtil.h"
#include "nsString.h"

namespace mozilla::net {

EarlyHintsService::EarlyHintsService()
   : mOngoingEarlyHints(new OngoingEarlyHints()) {}

// implementing the destructor in the .cpp file to allow EarlyHintsService.h
// not to include EarlyHintPreloader.h, decoupling the two files and hopefully
// allow faster compile times
EarlyHintsService::~EarlyHintsService() = default;

void EarlyHintsService::EarlyHint(
   const nsACString& aLinkHeader, nsIURI* aBaseURI, nsIChannel* aChannel,
   const nsACString& aReferrerPolicy, const nsACString& aCSPHeader,
   dom::CanonicalBrowsingContext* aLoadingBrowsingContext) {
 mEarlyHintsCount++;
 if (mFirstEarlyHint.isNothing()) {
   mFirstEarlyHint.emplace(TimeStamp::NowLoRes());
 } else {
   // Only allow one early hint response with link headers. See
   // https://html.spec.whatwg.org/multipage/semantics.html#early-hints
   // > Note: Only the first early hint response served during the navigation
   // > is handled, and it is discarded if it is succeeded by a cross-origin
   // > redirect.
   return;
 }

 nsCOMPtr<nsILoadInfo> loadInfo = aChannel->LoadInfo();
 // We only follow Early Hints sent on the main document. Make sure that we got
 // the main document channel here.
 if (loadInfo->GetExternalContentPolicyType() !=
     ExtContentPolicy::TYPE_DOCUMENT) {
   MOZ_ASSERT(false, "Early Hint on non-document channel");
   return;
 }
 nsCOMPtr<nsIPrincipal> principal;
 // We want to set the top-level document as the triggeringPrincipal for the
 // load of the sub-resources (image, font, fetch, script, style, fetch and in
 // the future maybe more). We can't use the `triggeringPrincipal` of the main
 // document channel, because it is the `systemPrincipal` for user initiated
 // loads. Same for the `LoadInfo::FindPrincipalToInherit(aChannel)`.
 //
 // On 3xx redirects of the main document to cross site locations, all Early
 // Hint preloads get cancelled as specified in the whatwg spec:
 //
 //   Note: Only the first early hint response served during the navigation is
 //   handled, and it is discarded if it is succeeded by a cross-origin
 //   redirect. [1]
 //
 // Therefore the channel doesn't need to change the principal for any reason
 // and has the correct principal for the whole lifetime.
 //
 // [1]: https://html.spec.whatwg.org/multipage/semantics.html#early-hints
 nsresult rv = nsContentUtils::GetSecurityManager()->GetChannelResultPrincipal(
     aChannel, getter_AddRefs(principal));
 NS_ENSURE_SUCCESS_VOID(rv);

 nsCOMPtr<nsICookieJarSettings> cookieJarSettings;
 if (NS_FAILED(
         loadInfo->GetCookieJarSettings(getter_AddRefs(cookieJarSettings)))) {
   return;
 }

 // TODO: find out why LinkHeaderParser uses utf16 and check if it can be
 //       changed to utf8
 auto linkHeaders = ParseLinkHeader(NS_ConvertUTF8toUTF16(aLinkHeader));

 for (auto& linkHeader : linkHeaders) {
   if (linkHeader.mRel.LowerCaseEqualsLiteral("preconnect")) {
     mLinkType |= dom::LinkStyle::ePRECONNECT;
     OriginAttributes originAttributes;
     StoragePrincipalHelper::GetOriginAttributesForNetworkState(
         aChannel, originAttributes);
     EarlyHintPreconnect::MaybePreconnect(linkHeader, aBaseURI,
                                          std::move(originAttributes));
   } else if (linkHeader.mRel.LowerCaseEqualsLiteral("preload")) {
     mLinkType |= dom::LinkStyle::ePRELOAD;
     EarlyHintPreloader::MaybeCreateAndInsertPreload(
         mOngoingEarlyHints, linkHeader, aBaseURI, principal,
         cookieJarSettings, aReferrerPolicy, aCSPHeader,
         loadInfo->GetBrowsingContextID(), aLoadingBrowsingContext, false);
   } else if (linkHeader.mRel.LowerCaseEqualsLiteral("modulepreload")) {
     mLinkType |= dom::LinkStyle::eMODULE_PRELOAD;
     EarlyHintPreloader::MaybeCreateAndInsertPreload(
         mOngoingEarlyHints, linkHeader, aBaseURI, principal,
         cookieJarSettings, aReferrerPolicy, aCSPHeader,
         loadInfo->GetBrowsingContextID(), aLoadingBrowsingContext, true);
   } else if (linkHeader.mRel.LowerCaseEqualsLiteral(
                  "compression-dictionary")) {
     mLinkType |= dom::LinkStyle::eCOMPRESSION_DICTIONARY;
     EarlyHintPreloader::MaybeCreateAndInsertPreload(
         mOngoingEarlyHints, linkHeader, aBaseURI, principal,
         cookieJarSettings, aReferrerPolicy, aCSPHeader,
         loadInfo->GetBrowsingContextID(), aLoadingBrowsingContext, true);
   }
 }
}

void EarlyHintsService::Cancel(const nsACString& aReason) {
 Reset();
 mOngoingEarlyHints->CancelAll(aReason);
}

void EarlyHintsService::RegisterLinksAndGetConnectArgs(
   dom::ContentParentId aCpId, nsTArray<EarlyHintConnectArgs>& aOutLinks) {
 mOngoingEarlyHints->RegisterLinksAndGetConnectArgs(aCpId, aOutLinks);
}

void EarlyHintsService::Reset() {
 if (mEarlyHintsCount == 0) {
   return;
 }
 // Reset telemetry counters and timestamps.
 mEarlyHintsCount = 0;
 mFirstEarlyHint = Nothing();
}

}  // namespace mozilla::net