Adding upstream version 124.0.1.upstream/124.0.1

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1065 insertions, 0 deletions

diff --git a/dom/security/nsMixedContentBlocker.cpp b/dom/security/nsMixedContentBlocker.cpp
new file mode 100644
index 0000000000..5ca8a9743a
--- /dev/null
+++ b/dom/security/nsMixedContentBlocker.cpp
@@ -0,0 +1,1065 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 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 "nsMixedContentBlocker.h"
+
+#include "nsContentPolicyUtils.h"
+#include "nsCSPContext.h"
+#include "nsThreadUtils.h"
+#include "nsINode.h"
+#include "nsCOMPtr.h"
+#include "nsDocShell.h"
+#include "nsIWebProgressListener.h"
+#include "nsContentUtils.h"
+#include "mozilla/dom/BrowsingContext.h"
+#include "mozilla/dom/WindowContext.h"
+#include "mozilla/dom/Document.h"
+#include "nsIChannel.h"
+#include "nsIParentChannel.h"
+#include "mozilla/Preferences.h"
+#include "nsIScriptObjectPrincipal.h"
+#include "nsIProtocolHandler.h"
+#include "nsCharSeparatedTokenizer.h"
+#include "nsISecureBrowserUI.h"
+#include "nsIWebNavigation.h"
+#include "nsLoadGroup.h"
+#include "nsIScriptError.h"
+#include "nsIURI.h"
+#include "nsIChannelEventSink.h"
+#include "nsNetUtil.h"
+#include "nsAsyncRedirectVerifyHelper.h"
+#include "mozilla/LoadInfo.h"
+#include "nsISiteSecurityService.h"
+#include "prnetdb.h"
+#include "nsQueryObject.h"
+
+#include "mozilla/BasePrincipal.h"
+#include "mozilla/Logging.h"
+#include "mozilla/StaticPrefs_dom.h"
+#include "mozilla/StaticPrefs_fission.h"
+#include "mozilla/StaticPrefs_security.h"
+#include "mozilla/Telemetry.h"
+#include "mozilla/dom/ContentChild.h"
+#include "mozilla/ipc/URIUtils.h"
+#include "mozilla/net/DNS.h"
+#include "mozilla/net/DocumentLoadListener.h"
+#include "mozilla/net/DocumentChannel.h"
+
+#include "mozilla/dom/nsHTTPSOnlyUtils.h"
+
+using namespace mozilla;
+using namespace mozilla::dom;
+
+static mozilla::LazyLogModule sMCBLog("MCBLog");
+
+enum nsMixedContentBlockerMessageType { eBlocked = 0x00, eUserOverride = 0x01 };
+
+// Allowlist of hostnames that should be considered secure contexts even when
+// served over http:// or ws://
+nsCString* nsMixedContentBlocker::sSecurecontextAllowlist = nullptr;
+bool nsMixedContentBlocker::sSecurecontextAllowlistCached = false;
+
+enum MixedContentHSTSState {
+  MCB_HSTS_PASSIVE_NO_HSTS = 0,
+  MCB_HSTS_PASSIVE_WITH_HSTS = 1,
+  MCB_HSTS_ACTIVE_NO_HSTS = 2,
+  MCB_HSTS_ACTIVE_WITH_HSTS = 3
+};
+
+nsMixedContentBlocker::~nsMixedContentBlocker() = default;
+
+NS_IMPL_ISUPPORTS(nsMixedContentBlocker, nsIContentPolicy, nsIChannelEventSink)
+
+static void LogMixedContentMessage(
+    MixedContentTypes aClassification, nsIURI* aContentLocation,
+    uint64_t aInnerWindowID, nsMixedContentBlockerMessageType aMessageType,
+    nsIURI* aRequestingLocation,
+    const nsACString& aOverruleMessageLookUpKeyWithThis = ""_ns) {
+  nsAutoCString messageCategory;
+  uint32_t severityFlag;
+  nsAutoCString messageLookupKey;
+
+  if (aMessageType == eBlocked) {
+    severityFlag = nsIScriptError::errorFlag;
+    messageCategory.AssignLiteral("Mixed Content Blocker");
+    if (aClassification == eMixedDisplay) {
+      messageLookupKey.AssignLiteral("BlockMixedDisplayContent");
+    } else {
+      messageLookupKey.AssignLiteral("BlockMixedActiveContent");
+    }
+  } else {
+    severityFlag = nsIScriptError::warningFlag;
+    messageCategory.AssignLiteral("Mixed Content Message");
+    if (aClassification == eMixedDisplay) {
+      messageLookupKey.AssignLiteral("LoadingMixedDisplayContent2");
+    } else {
+      messageLookupKey.AssignLiteral("LoadingMixedActiveContent2");
+    }
+  }
+
+  // if the callee explicitly wants to use a special message for this
+  // console report, then we allow to overrule the default with the
+  // explicitly provided one here.
+  if (!aOverruleMessageLookUpKeyWithThis.IsEmpty()) {
+    messageLookupKey = aOverruleMessageLookUpKeyWithThis;
+  }
+
+  nsAutoString localizedMsg;
+  AutoTArray<nsString, 1> params;
+  CopyUTF8toUTF16(aContentLocation->GetSpecOrDefault(),
+                  *params.AppendElement());
+  nsContentUtils::FormatLocalizedString(nsContentUtils::eSECURITY_PROPERTIES,
+                                        messageLookupKey.get(), params,
+                                        localizedMsg);
+
+  nsContentUtils::ReportToConsoleByWindowID(localizedMsg, severityFlag,
+                                            messageCategory, aInnerWindowID,
+                                            aRequestingLocation);
+}
+
+/* nsIChannelEventSink implementation
+ * This code is called when a request is redirected.
+ * We check the channel associated with the new uri is allowed to load
+ * in the current context
+ */
+NS_IMETHODIMP
+nsMixedContentBlocker::AsyncOnChannelRedirect(
+    nsIChannel* aOldChannel, nsIChannel* aNewChannel, uint32_t aFlags,
+    nsIAsyncVerifyRedirectCallback* aCallback) {
+  mozilla::net::nsAsyncRedirectAutoCallback autoCallback(aCallback);
+
+  if (!aOldChannel) {
+    NS_ERROR("No channel when evaluating mixed content!");
+    return NS_ERROR_FAILURE;
+  }
+
+  // If we are in the parent process in e10s, we don't have access to the
+  // document node, and hence ShouldLoad will fail when we try to get
+  // the docShell.  If that's the case, ignore mixed content checks
+  // on redirects in the parent.  Let the child check for mixed content.
+  nsCOMPtr<nsIParentChannel> is_ipc_channel;
+  NS_QueryNotificationCallbacks(aNewChannel, is_ipc_channel);
+  RefPtr<net::DocumentLoadListener> docListener =
+      do_QueryObject(is_ipc_channel);
+  if (is_ipc_channel && !docListener) {
+    return NS_OK;
+  }
+
+  // Don't do these checks if we're switching from DocumentChannel
+  // to a real channel. In that case, we should already have done
+  // the checks in the parent process. AsyncOnChannelRedirect
+  // isn't called in the content process if we switch process,
+  // so checking here would just hide bugs in the process switch
+  // cases.
+  if (RefPtr<net::DocumentChannel> docChannel = do_QueryObject(aOldChannel)) {
+    return NS_OK;
+  }
+
+  nsresult rv;
+  nsCOMPtr<nsIURI> oldUri;
+  rv = aOldChannel->GetURI(getter_AddRefs(oldUri));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  nsCOMPtr<nsIURI> newUri;
+  rv = aNewChannel->GetURI(getter_AddRefs(newUri));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // Get the loading Info from the old channel
+  nsCOMPtr<nsILoadInfo> loadInfo = aOldChannel->LoadInfo();
+  nsCOMPtr<nsIPrincipal> requestingPrincipal = loadInfo->GetLoadingPrincipal();
+
+  // Since we are calling shouldLoad() directly on redirects, we don't go
+  // through the code in nsContentPolicyUtils::NS_CheckContentLoadPolicy().
+  // Hence, we have to duplicate parts of it here.
+  if (requestingPrincipal) {
+    // We check to see if the loadingPrincipal is systemPrincipal and return
+    // early if it is
+    if (requestingPrincipal->IsSystemPrincipal()) {
+      return NS_OK;
+    }
+  }
+
+  int16_t decision = REJECT_REQUEST;
+  rv = ShouldLoad(newUri, loadInfo, &decision);
+  if (NS_FAILED(rv)) {
+    autoCallback.DontCallback();
+    aOldChannel->Cancel(NS_ERROR_DOM_BAD_URI);
+    return NS_BINDING_FAILED;
+  }
+
+  // If the channel is about to load mixed content, abort the channel
+  if (!NS_CP_ACCEPTED(decision)) {
+    autoCallback.DontCallback();
+    aOldChannel->Cancel(NS_ERROR_DOM_BAD_URI);
+    return NS_BINDING_FAILED;
+  }
+
+  return NS_OK;
+}
+
+/* This version of ShouldLoad() is non-static and called by the Content Policy
+ * API and AsyncOnChannelRedirect().  See nsIContentPolicy::ShouldLoad()
+ * for detailed description of the parameters.
+ */
+NS_IMETHODIMP
+nsMixedContentBlocker::ShouldLoad(nsIURI* aContentLocation,
+                                  nsILoadInfo* aLoadInfo, int16_t* aDecision) {
+  // We pass in false as the first parameter to ShouldLoad(), because the
+  // callers of this method don't know whether the load went through cached
+  // image redirects.  This is handled by direct callers of the static
+  // ShouldLoad.
+  nsresult rv = ShouldLoad(false,  // aHadInsecureImageRedirect
+                           aContentLocation, aLoadInfo, true, aDecision);
+
+  if (*aDecision == nsIContentPolicy::REJECT_REQUEST) {
+    NS_SetRequestBlockingReason(aLoadInfo,
+                                nsILoadInfo::BLOCKING_REASON_MIXED_BLOCKED);
+  }
+
+  return rv;
+}
+
+bool nsMixedContentBlocker::IsPotentiallyTrustworthyLoopbackHost(
+    const nsACString& aAsciiHost) {
+  if (mozilla::net::IsLoopbackHostname(aAsciiHost)) {
+    return true;
+  }
+
+  using namespace mozilla::net;
+  NetAddr addr;
+  if (NS_FAILED(addr.InitFromString(aAsciiHost))) {
+    return false;
+  }
+
+  // Step 4 of
+  // https://w3c.github.io/webappsec-secure-contexts/#is-origin-trustworthy says
+  // we should only consider [::1]/128 as a potentially trustworthy IPv6
+  // address, whereas for IPv4 127.0.0.1/8 are considered as potentially
+  // trustworthy.
+  return addr.IsLoopBackAddressWithoutIPv6Mapping();
+}
+
+bool nsMixedContentBlocker::IsPotentiallyTrustworthyLoopbackURL(nsIURI* aURL) {
+  if (!aURL) {
+    return false;
+  }
+  nsAutoCString asciiHost;
+  nsresult rv = aURL->GetAsciiHost(asciiHost);
+  NS_ENSURE_SUCCESS(rv, false);
+  return IsPotentiallyTrustworthyLoopbackHost(asciiHost);
+}
+
+/* Maybe we have a .onion URL. Treat it as trustworthy as well if
+ * `dom.securecontext.allowlist_onions` is `true`.
+ */
+bool nsMixedContentBlocker::IsPotentiallyTrustworthyOnion(nsIURI* aURL) {
+  if (!StaticPrefs::dom_securecontext_allowlist_onions()) {
+    return false;
+  }
+
+  nsAutoCString host;
+  nsresult rv = aURL->GetHost(host);
+  NS_ENSURE_SUCCESS(rv, false);
+  return StringEndsWith(host, ".onion"_ns);
+}
+
+// static
+void nsMixedContentBlocker::OnPrefChange(const char* aPref, void* aClosure) {
+  MOZ_ASSERT(NS_IsMainThread());
+  MOZ_ASSERT(!strcmp(aPref, "dom.securecontext.allowlist"));
+  Preferences::GetCString("dom.securecontext.allowlist",
+                          *sSecurecontextAllowlist);
+}
+
+// static
+void nsMixedContentBlocker::GetSecureContextAllowList(nsACString& aList) {
+  MOZ_ASSERT(NS_IsMainThread());
+  if (!sSecurecontextAllowlistCached) {
+    MOZ_ASSERT(!sSecurecontextAllowlist);
+    sSecurecontextAllowlistCached = true;
+    sSecurecontextAllowlist = new nsCString();
+    Preferences::RegisterCallbackAndCall(OnPrefChange,
+                                         "dom.securecontext.allowlist");
+  }
+  aList = *sSecurecontextAllowlist;
+}
+
+// static
+void nsMixedContentBlocker::Shutdown() {
+  if (sSecurecontextAllowlist) {
+    delete sSecurecontextAllowlist;
+    sSecurecontextAllowlist = nullptr;
+  }
+}
+
+bool nsMixedContentBlocker::IsPotentiallyTrustworthyOrigin(nsIURI* aURI) {
+  // The following implements:
+  // https://w3c.github.io/webappsec-secure-contexts/#is-origin-trustworthy
+
+  nsAutoCString scheme;
+  nsresult rv = aURI->GetScheme(scheme);
+  if (NS_FAILED(rv)) {
+    return false;
+  }
+
+  // Blobs are expected to inherit their principal so we don't expect to have
+  // a content principal with scheme 'blob' here.  We can't assert that though
+  // since someone could mess with a non-blob URI to give it that scheme.
+  NS_WARNING_ASSERTION(!scheme.EqualsLiteral("blob"),
+                       "IsOriginPotentiallyTrustworthy ignoring blob scheme");
+
+  // According to the specification, the user agent may choose to extend the
+  // trust to other, vendor-specific URL schemes. We use this for "resource:",
+  // which is technically a substituting protocol handler that is not limited to
+  // local resource mapping, but in practice is never mapped remotely as this
+  // would violate assumptions a lot of code makes.
+  // We use nsIProtocolHandler flags to determine which protocols we consider a
+  // priori authenticated.
+  bool aPrioriAuthenticated = false;
+  if (NS_FAILED(NS_URIChainHasFlags(
+          aURI, nsIProtocolHandler::URI_IS_POTENTIALLY_TRUSTWORTHY,
+          &aPrioriAuthenticated))) {
+    return false;
+  }
+
+  if (aPrioriAuthenticated) {
+    return true;
+  }
+
+  nsAutoCString host;
+  rv = aURI->GetHost(host);
+  if (NS_FAILED(rv)) {
+    return false;
+  }
+
+  if (IsPotentiallyTrustworthyLoopbackURL(aURI)) {
+    return true;
+  }
+
+  // If a host is not considered secure according to the default algorithm, then
+  // check to see if it has been allowlisted by the user.  We only apply this
+  // allowlist for network resources, i.e., those with scheme "http" or "ws".
+  // The pref should contain a comma-separated list of hostnames.
+
+  if (!scheme.EqualsLiteral("http") && !scheme.EqualsLiteral("ws")) {
+    return false;
+  }
+
+  nsAutoCString allowlist;
+  GetSecureContextAllowList(allowlist);
+  for (const nsACString& allowedHost :
+       nsCCharSeparatedTokenizer(allowlist, ',').ToRange()) {
+    if (host.Equals(allowedHost)) {
+      return true;
+    }
+  }
+
+  // Maybe we have a .onion URL. Treat it as trustworthy as well if
+  // `dom.securecontext.allowlist_onions` is `true`.
+  if (nsMixedContentBlocker::IsPotentiallyTrustworthyOnion(aURI)) {
+    return true;
+  }
+  return false;
+}
+
+/* static */
+bool nsMixedContentBlocker::IsUpgradableContentType(nsContentPolicyType aType,
+                                                    bool aConsiderPrefs) {
+  MOZ_ASSERT(NS_IsMainThread());
+
+  if (aConsiderPrefs &&
+      !StaticPrefs::security_mixed_content_upgrade_display_content()) {
+    return false;
+  }
+
+  switch (aType) {
+    case nsIContentPolicy::TYPE_INTERNAL_IMAGE:
+    case nsIContentPolicy::TYPE_INTERNAL_IMAGE_PRELOAD:
+      return !aConsiderPrefs ||
+             StaticPrefs::
+                 security_mixed_content_upgrade_display_content_image();
+    case nsIContentPolicy::TYPE_INTERNAL_AUDIO:
+      return !aConsiderPrefs ||
+             StaticPrefs::
+                 security_mixed_content_upgrade_display_content_audio();
+    case nsIContentPolicy::TYPE_INTERNAL_VIDEO:
+      return !aConsiderPrefs ||
+             StaticPrefs::
+                 security_mixed_content_upgrade_display_content_video();
+    default:
+      return false;
+  }
+}
+
+/*
+ * Return the URI of the precusor principal or the URI of aPrincipal if there is
+ * no precursor URI.
+ */
+static already_AddRefed<nsIURI> GetPrincipalURIOrPrecursorPrincipalURI(
+    nsIPrincipal* aPrincipal) {
+  nsCOMPtr<nsIPrincipal> precursorPrincipal =
+      aPrincipal->GetPrecursorPrincipal();
+
+#ifdef DEBUG
+  if (precursorPrincipal) {
+    MOZ_ASSERT(aPrincipal->GetIsNullPrincipal(),
+               "Only Null Principals should have a Precursor Principal");
+  }
+#endif
+
+  return precursorPrincipal ? precursorPrincipal->GetURI()
+                            : aPrincipal->GetURI();
+}
+
+/* Static version of ShouldLoad() that contains all the Mixed Content Blocker
+ * logic.  Called from non-static ShouldLoad().
+ */
+nsresult nsMixedContentBlocker::ShouldLoad(bool aHadInsecureImageRedirect,
+                                           nsIURI* aContentLocation,
+                                           nsILoadInfo* aLoadInfo,
+                                           bool aReportError,
+                                           int16_t* aDecision) {
+  // Asserting that we are on the main thread here and hence do not have to lock
+  // and unlock security.mixed_content.block_active_content and
+  // security.mixed_content.block_display_content before reading/writing to
+  // them.
+  MOZ_ASSERT(NS_IsMainThread());
+
+  if (MOZ_UNLIKELY(MOZ_LOG_TEST(sMCBLog, LogLevel::Verbose))) {
+    nsAutoCString asciiUrl;
+    aContentLocation->GetAsciiSpec(asciiUrl);
+    MOZ_LOG(sMCBLog, LogLevel::Verbose, ("shouldLoad:"));
+    MOZ_LOG(sMCBLog, LogLevel::Verbose,
+            ("  - contentLocation: %s", asciiUrl.get()));
+  }
+
+  nsContentPolicyType internalContentType =
+      aLoadInfo->InternalContentPolicyType();
+  nsCOMPtr<nsIPrincipal> loadingPrincipal = aLoadInfo->GetLoadingPrincipal();
+  nsCOMPtr<nsIPrincipal> triggeringPrincipal = aLoadInfo->TriggeringPrincipal();
+
+  if (MOZ_UNLIKELY(MOZ_LOG_TEST(sMCBLog, LogLevel::Verbose))) {
+    MOZ_LOG(sMCBLog, LogLevel::Verbose,
+            ("  - internalContentPolicyType: %s",
+             NS_CP_ContentTypeName(internalContentType)));
+
+    if (loadingPrincipal != nullptr) {
+      nsAutoCString loadingPrincipalAsciiUrl;
+      loadingPrincipal->GetAsciiSpec(loadingPrincipalAsciiUrl);
+      MOZ_LOG(sMCBLog, LogLevel::Verbose,
+              ("  - loadingPrincipal: %s", loadingPrincipalAsciiUrl.get()));
+    } else {
+      MOZ_LOG(sMCBLog, LogLevel::Verbose, ("  - loadingPrincipal: (nullptr)"));
+    }
+
+    nsAutoCString triggeringPrincipalAsciiUrl;
+    triggeringPrincipal->GetAsciiSpec(triggeringPrincipalAsciiUrl);
+    MOZ_LOG(sMCBLog, LogLevel::Verbose,
+            ("  - triggeringPrincipal: %s", triggeringPrincipalAsciiUrl.get()));
+  }
+
+  RefPtr<WindowContext> requestingWindow =
+      WindowContext::GetById(aLoadInfo->GetInnerWindowID());
+
+  bool isPreload = nsContentUtils::IsPreloadType(internalContentType);
+
+  // The content policy type that we receive may be an internal type for
+  // scripts.  Let's remember if we have seen a worker type, and reset it to the
+  // external type in all cases right now.
+  bool isWorkerType =
+      internalContentType == nsIContentPolicy::TYPE_INTERNAL_WORKER ||
+      internalContentType ==
+          nsIContentPolicy::TYPE_INTERNAL_WORKER_STATIC_MODULE ||
+      internalContentType == nsIContentPolicy::TYPE_INTERNAL_SHARED_WORKER ||
+      internalContentType == nsIContentPolicy::TYPE_INTERNAL_SERVICE_WORKER;
+  ExtContentPolicyType contentType =
+      nsContentUtils::InternalContentPolicyTypeToExternal(internalContentType);
+
+  // Assume active (high risk) content and blocked by default
+  MixedContentTypes classification = eMixedScript;
+  // Make decision to block/reject by default
+  *aDecision = REJECT_REQUEST;
+
+  // Notes on non-obvious decisions:
+  //
+  // TYPE_DTD: A DTD can contain entity definitions that expand to scripts.
+  //
+  // TYPE_FONT: The TrueType hinting mechanism is basically a scripting
+  // language that gets interpreted by the operating system's font rasterizer.
+  // Mixed content web fonts are relatively uncommon, and we can can fall back
+  // to built-in fonts with minimal disruption in almost all cases.
+  //
+  // TYPE_OBJECT_SUBREQUEST could actually be either active content (e.g. a
+  // script that a plugin will execute) or display content (e.g. Flash video
+  // content).  Until we have a way to determine active vs passive content
+  // from plugin requests (bug 836352), we will treat this as passive content.
+  // This is to prevent false positives from causing users to become
+  // desensitized to the mixed content blocker.
+  //
+  // TYPE_CSP_REPORT: High-risk because they directly leak information about
+  // the content of the page, and because blocking them does not have any
+  // negative effect on the page loading.
+  //
+  // TYPE_PING: Ping requests are POSTS, not GETs like images and media.
+  // Also, PING requests have no bearing on the rendering or operation of
+  // the page when used as designed, so even though they are lower risk than
+  // scripts, blocking them is basically risk-free as far as compatibility is
+  // concerned.
+  //
+  // TYPE_STYLESHEET: XSLT stylesheets can insert scripts. CSS positioning
+  // and other advanced CSS features can possibly be exploited to cause
+  // spoofing attacks (e.g. make a "grant permission" button look like a
+  // "refuse permission" button).
+  //
+  // TYPE_BEACON: Beacon requests are similar to TYPE_PING, and are blocked by
+  // default.
+  //
+  // TYPE_WEBSOCKET: The Websockets API requires browsers to
+  // reject mixed-content websockets: "If secure is false but the origin of
+  // the entry script has a scheme component that is itself a secure protocol,
+  // e.g. HTTPS, then throw a SecurityError exception." We already block mixed
+  // content websockets within the websockets implementation, so we don't need
+  // to do any blocking here, nor do we need to provide a way to undo or
+  // override the blocking. Websockets without TLS are very flaky anyway in the
+  // face of many HTTP-aware proxies. Compared to passive content, there is
+  // additional risk that the script using WebSockets will disclose sensitive
+  // information from the HTTPS page and/or eval (directly or indirectly)
+  // received data.
+  //
+  // TYPE_XMLHTTPREQUEST: XHR requires either same origin or CORS, so most
+  // mixed-content XHR will already be blocked by that check. This will also
+  // block HTTPS-to-HTTP XHR with CORS. The same security concerns mentioned
+  // above for WebSockets apply to XHR, and XHR should have the same security
+  // properties as WebSockets w.r.t. mixed content. XHR's handling of redirects
+  // amplifies these concerns.
+  //
+  // TYPE_PROXIED_WEBRTC_MEDIA: Ordinarily, webrtc uses low-level sockets for
+  // peer-to-peer media, which bypasses this code entirely. However, when a
+  // web proxy is being used, the TCP and TLS webrtc connections are routed
+  // through the web proxy (using HTTP CONNECT), which causes these connections
+  // to be checked. We just skip mixed content blocking in that case.
+
+  switch (contentType) {
+    // The top-level document cannot be mixed content by definition
+    case ExtContentPolicy::TYPE_DOCUMENT:
+      *aDecision = ACCEPT;
+      return NS_OK;
+    // Creating insecure websocket connections in a secure page is blocked
+    // already in the websocket constructor. We don't need to check the blocking
+    // here and we don't want to un-block
+    case ExtContentPolicy::TYPE_WEBSOCKET:
+      *aDecision = ACCEPT;
+      return NS_OK;
+
+      // TYPE_SAVEAS_DOWNLOAD: Save-link-as feature is used to download a
+      // resource
+      // without involving a docShell. This kind of loading must be
+      // allowed, if not disabled in the preferences.
+      // Creating insecure connections for a save-as link download is
+      // acceptable. This download is completely disconnected from the docShell,
+      // but still using the same loading principal.
+
+    case ExtContentPolicy::TYPE_SAVEAS_DOWNLOAD:
+      *aDecision = ACCEPT;
+      return NS_OK;
+      break;
+
+    // It does not make sense to subject webrtc media connections to mixed
+    // content blocking, since those connections are peer-to-peer and will
+    // therefore almost never match the origin.
+    case ExtContentPolicy::TYPE_PROXIED_WEBRTC_MEDIA:
+      *aDecision = ACCEPT;
+      return NS_OK;
+
+    // Static display content is considered moderate risk for mixed content so
+    // these will be blocked according to the mixed display preference
+    case ExtContentPolicy::TYPE_IMAGE:
+    case ExtContentPolicy::TYPE_MEDIA:
+      classification = eMixedDisplay;
+      break;
+    case ExtContentPolicy::TYPE_OBJECT_SUBREQUEST:
+      if (StaticPrefs::security_mixed_content_block_object_subrequest()) {
+        classification = eMixedScript;
+      } else {
+        classification = eMixedDisplay;
+      }
+      break;
+
+    // Active content (or content with a low value/risk-of-blocking ratio)
+    // that has been explicitly evaluated; listed here for documentation
+    // purposes and to avoid the assertion and warning for the default case.
+    case ExtContentPolicy::TYPE_BEACON:
+    case ExtContentPolicy::TYPE_CSP_REPORT:
+    case ExtContentPolicy::TYPE_DTD:
+    case ExtContentPolicy::TYPE_FETCH:
+    case ExtContentPolicy::TYPE_FONT:
+    case ExtContentPolicy::TYPE_UA_FONT:
+    case ExtContentPolicy::TYPE_IMAGESET:
+    case ExtContentPolicy::TYPE_OBJECT:
+    case ExtContentPolicy::TYPE_SCRIPT:
+    case ExtContentPolicy::TYPE_STYLESHEET:
+    case ExtContentPolicy::TYPE_SUBDOCUMENT:
+    case ExtContentPolicy::TYPE_PING:
+    case ExtContentPolicy::TYPE_WEB_MANIFEST:
+    case ExtContentPolicy::TYPE_XMLHTTPREQUEST:
+    case ExtContentPolicy::TYPE_XSLT:
+    case ExtContentPolicy::TYPE_OTHER:
+    case ExtContentPolicy::TYPE_SPECULATIVE:
+    case ExtContentPolicy::TYPE_WEB_TRANSPORT:
+    case ExtContentPolicy::TYPE_WEB_IDENTITY:
+      break;
+
+    case ExtContentPolicy::TYPE_INVALID:
+      MOZ_ASSERT(false, "Mixed content of unknown type");
+      // Do not add default: so that compilers can catch the missing case.
+  }
+
+  // Make sure to get the URI the load started with. No need to check
+  // outer schemes because all the wrapping pseudo protocols inherit the
+  // security properties of the actual network request represented
+  // by the innerMost URL.
+  nsCOMPtr<nsIURI> innerContentLocation = NS_GetInnermostURI(aContentLocation);
+  if (!innerContentLocation) {
+    NS_ERROR("Can't get innerURI from aContentLocation");
+    *aDecision = REJECT_REQUEST;
+    MOZ_LOG(sMCBLog, LogLevel::Verbose,
+            ("  -> decision: Request will be rejected because the innermost "
+             "URI could not be "
+             "retrieved"));
+    return NS_OK;
+  }
+
+  // TYPE_IMAGE redirects are cached based on the original URI, not the final
+  // destination and hence cache hits for images may not have the correct
+  // innerContentLocation.  Check if the cached hit went through an http
+  // redirect, and if it did, we can't treat this as a secure subresource.
+  if (!aHadInsecureImageRedirect &&
+      URISafeToBeLoadedInSecureContext(innerContentLocation)) {
+    *aDecision = ACCEPT;
+    return NS_OK;
+  }
+
+  /*
+   * Most likely aLoadingPrincipal reflects the security context of the owning
+   * document for this mixed content check. There are cases where that is not
+   * true, hence we have to we process requests in the following order:
+   * 1) If the load is triggered by the SystemPrincipal, we allow the load.
+   *    Content scripts from addon code do provide aTriggeringPrincipal, which
+   *    is an ExpandedPrincipal. If encountered, we allow the load.
+   * 2) If aLoadingPrincipal does not yield to a requestingLocation, then we
+   *    fall back to querying the requestingLocation from aTriggeringPrincipal.
+   * 3) If we still end up not having a requestingLocation, we reject the load.
+   */
+
+  // 1) Check if the load was triggered by the system (SystemPrincipal) or
+  // a content script from addons code (ExpandedPrincipal) in which case the
+  // load is not subject to mixed content blocking.
+  if (triggeringPrincipal) {
+    if (triggeringPrincipal->IsSystemPrincipal()) {
+      *aDecision = ACCEPT;
+      return NS_OK;
+    }
+    nsCOMPtr<nsIExpandedPrincipal> expanded =
+        do_QueryInterface(triggeringPrincipal);
+    if (expanded) {
+      *aDecision = ACCEPT;
+      return NS_OK;
+    }
+  }
+
+  // 2) If aLoadingPrincipal does not provide a requestingLocation, then
+  // we fall back to to querying the requestingLocation from
+  // aTriggeringPrincipal.
+  nsCOMPtr<nsIURI> requestingLocation =
+      GetPrincipalURIOrPrecursorPrincipalURI(loadingPrincipal);
+  if (!requestingLocation) {
+    requestingLocation =
+        GetPrincipalURIOrPrecursorPrincipalURI(triggeringPrincipal);
+  }
+
+  // 3) Giving up. We still don't have a requesting location, therefore we can't
+  // tell if this is a mixed content load. Deny to be safe.
+  if (!requestingLocation) {
+    *aDecision = REJECT_REQUEST;
+    MOZ_LOG(sMCBLog, LogLevel::Verbose,
+            ("  -> decision: Request will be rejected because no requesting "
+             "location could be "
+             "gathered."));
+    return NS_OK;
+  }
+
+  // Check the parent scheme. If it is not an HTTPS page then mixed content
+  // restrictions do not apply.
+  nsCOMPtr<nsIURI> innerRequestingLocation =
+      NS_GetInnermostURI(requestingLocation);
+  if (!innerRequestingLocation) {
+    NS_ERROR("Can't get innerURI from requestingLocation");
+    *aDecision = REJECT_REQUEST;
+    MOZ_LOG(sMCBLog, LogLevel::Verbose,
+            ("  -> decision: Request will be rejected because the innermost "
+             "URI of the "
+             "requesting location could be gathered."));
+    return NS_OK;
+  }
+
+  bool parentIsHttps = innerRequestingLocation->SchemeIs("https");
+  if (!parentIsHttps) {
+    *aDecision = ACCEPT;
+    MOZ_LOG(sMCBLog, LogLevel::Verbose,
+            ("  -> decision: Request will be allowed because the requesting "
+             "location is not using "
+             "HTTPS."));
+    return NS_OK;
+  }
+
+  // Disallow mixed content loads for workers, shared workers and service
+  // workers.
+  if (isWorkerType) {
+    // For workers, we can assume that we're mixed content at this point, since
+    // the parent is https, and the protocol associated with
+    // innerContentLocation doesn't map to the secure URI flags checked above.
+    // Assert this for sanity's sake
+#ifdef DEBUG
+    bool isHttpsScheme = innerContentLocation->SchemeIs("https");
+    MOZ_ASSERT(!isHttpsScheme);
+#endif
+    *aDecision = REJECT_REQUEST;
+    MOZ_LOG(sMCBLog, LogLevel::Verbose,
+            ("  -> decision: Request will be rejected, trying to load a worker "
+             "from an insecure origin."));
+    return NS_OK;
+  }
+
+  bool isHttpScheme = innerContentLocation->SchemeIs("http");
+  if (isHttpScheme && IsPotentiallyTrustworthyOrigin(innerContentLocation)) {
+    *aDecision = ACCEPT;
+    return NS_OK;
+  }
+
+  // Check if https-only mode upgrades this later anyway
+  if (nsHTTPSOnlyUtils::IsSafeToAcceptCORSOrMixedContent(aLoadInfo)) {
+    *aDecision = ACCEPT;
+    return NS_OK;
+  }
+
+  // The page might have set the CSP directive 'upgrade-insecure-requests'. In
+  // such a case allow the http: load to succeed with the promise that the
+  // channel will get upgraded to https before fetching any data from the
+  // netwerk. Please see: nsHttpChannel::Connect()
+  //
+  // Please note that the CSP directive 'upgrade-insecure-requests' only applies
+  // to http: and ws: (for websockets). Websockets are not subject to mixed
+  // content blocking since insecure websockets are not allowed within secure
+  // pages. Hence, we only have to check against http: here. Skip mixed content
+  // blocking if the subresource load uses http: and the CSP directive
+  // 'upgrade-insecure-requests' is present on the page.
+
+  // Carve-out: if we're in the parent and we're loading media, e.g. through
+  // webbrowserpersist, don't reject it if we can't find a docshell.
+  if (XRE_IsParentProcess() && !requestingWindow &&
+      (contentType == ExtContentPolicy::TYPE_IMAGE ||
+       contentType == ExtContentPolicy::TYPE_MEDIA)) {
+    *aDecision = ACCEPT;
+    return NS_OK;
+  }
+  // Otherwise, we must have a window
+  NS_ENSURE_TRUE(requestingWindow, NS_OK);
+
+  if (isHttpScheme && aLoadInfo->GetUpgradeInsecureRequests()) {
+    *aDecision = ACCEPT;
+    return NS_OK;
+  }
+
+  // Allow http: mixed content if we are choosing to upgrade them when the
+  // pref "security.mixed_content.upgrade_display_content" is true.
+  // This behaves like GetUpgradeInsecureRequests above in that the channel will
+  // be upgraded to https before fetching any data from the netwerk.
+  if (isHttpScheme) {
+    bool isUpgradableContentType =
+        IsUpgradableContentType(internalContentType, /* aConsiderPrefs */ true);
+    if (isUpgradableContentType) {
+      *aDecision = ACCEPT;
+      return NS_OK;
+    }
+  }
+
+  // The page might have set the CSP directive 'block-all-mixed-content' which
+  // should block not only active mixed content loads but in fact all mixed
+  // content loads, see https://www.w3.org/TR/mixed-content/#strict-checking
+  // Block all non secure loads in case the CSP directive is present. Please
+  // note that at this point we already know, based on |schemeSecure| that the
+  // load is not secure, so we can bail out early at this point.
+  if (aLoadInfo->GetBlockAllMixedContent()) {
+    // log a message to the console before returning.
+    nsAutoCString spec;
+    nsresult rv = aContentLocation->GetSpec(spec);
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    AutoTArray<nsString, 1> params;
+    CopyUTF8toUTF16(spec, *params.AppendElement());
+
+    CSP_LogLocalizedStr("blockAllMixedContent", params,
+                        u""_ns,  // aSourceFile
+                        u""_ns,  // aScriptSample
+                        0,       // aLineNumber
+                        1,       // aColumnNumber
+                        nsIScriptError::errorFlag, "blockAllMixedContent"_ns,
+                        requestingWindow->Id(),
+                        !!aLoadInfo->GetOriginAttributes().mPrivateBrowsingId);
+    *aDecision = REJECT_REQUEST;
+    MOZ_LOG(
+        sMCBLog, LogLevel::Verbose,
+        ("  -> decision: Request will be rejected because the CSP directive "
+         "'block-all-mixed-content' was set while trying to load data from "
+         "a non-secure origin."));
+    return NS_OK;
+  }
+
+  // Determine if the rootDoc is https and if the user decided to allow Mixed
+  // Content
+  WindowContext* topWC = requestingWindow->TopWindowContext();
+  bool rootHasSecureConnection = topWC->GetIsSecure();
+  bool allowMixedContent = topWC->GetAllowMixedContent();
+
+  // When navigating an iframe, the iframe may be https but its parents may not
+  // be. Check the parents to see if any of them are https. If none of the
+  // parents are https, allow the load.
+  if (contentType == ExtContentPolicyType::TYPE_SUBDOCUMENT &&
+      !rootHasSecureConnection && !parentIsHttps) {
+    bool httpsParentExists = false;
+
+    RefPtr<WindowContext> curWindow = requestingWindow;
+    while (!httpsParentExists && curWindow) {
+      httpsParentExists = curWindow->GetIsSecure();
+      curWindow = curWindow->GetParentWindowContext();
+    }
+
+    if (!httpsParentExists) {
+      *aDecision = nsIContentPolicy::ACCEPT;
+      return NS_OK;
+    }
+  }
+
+  OriginAttributes originAttributes;
+  if (loadingPrincipal) {
+    originAttributes = loadingPrincipal->OriginAttributesRef();
+  } else if (triggeringPrincipal) {
+    originAttributes = triggeringPrincipal->OriginAttributesRef();
+  }
+
+  // At this point we know that the request is mixed content, and the only
+  // question is whether we block it.  Record telemetry at this point as to
+  // whether HSTS would have fixed things by making the content location
+  // into an HTTPS URL.
+  //
+  // Note that we count this for redirects as well as primary requests. This
+  // will cause some degree of double-counting, especially when mixed content
+  // is not blocked (e.g., for images).  For more detail, see:
+  //   https://bugzilla.mozilla.org/show_bug.cgi?id=1198572#c19
+  //
+  // We do not count requests aHadInsecureImageRedirect=true, since these are
+  // just an artifact of the image caching system.
+  bool active = (classification == eMixedScript);
+  if (!aHadInsecureImageRedirect) {
+    if (XRE_IsParentProcess()) {
+      AccumulateMixedContentHSTS(innerContentLocation, active,
+                                 originAttributes);
+    } else {
+      // Ask the parent process to do the same call
+      mozilla::dom::ContentChild* cc =
+          mozilla::dom::ContentChild::GetSingleton();
+      if (cc) {
+        cc->SendAccumulateMixedContentHSTS(innerContentLocation, active,
+                                           originAttributes);
+      }
+    }
+  }
+
+  // set hasMixedContentObjectSubrequest on this object if necessary
+  if (contentType == ExtContentPolicyType::TYPE_OBJECT_SUBREQUEST &&
+      aReportError) {
+    if (!StaticPrefs::security_mixed_content_block_object_subrequest()) {
+      nsAutoCString messageLookUpKey(
+          "LoadingMixedDisplayObjectSubrequestDeprecation");
+
+      LogMixedContentMessage(classification, aContentLocation, topWC->Id(),
+                             eUserOverride, requestingLocation,
+                             messageLookUpKey);
+    }
+  }
+
+  uint32_t newState = 0;
+  // If the content is display content, and the pref says display content should
+  // be blocked, block it.
+  if (classification == eMixedDisplay) {
+    if (!StaticPrefs::security_mixed_content_block_display_content() ||
+        allowMixedContent) {
+      *aDecision = nsIContentPolicy::ACCEPT;
+      // User has overriden the pref and the root is not https;
+      // mixed display content was allowed on an https subframe.
+      newState |= nsIWebProgressListener::STATE_LOADED_MIXED_DISPLAY_CONTENT;
+    } else {
+      *aDecision = nsIContentPolicy::REJECT_REQUEST;
+      MOZ_LOG(sMCBLog, LogLevel::Verbose,
+              ("  -> decision: Request will be rejected because the content is "
+               "display "
+               "content (blocked by pref "
+               "security.mixed_content.block_display_content)."));
+      newState |= nsIWebProgressListener::STATE_BLOCKED_MIXED_DISPLAY_CONTENT;
+    }
+  } else {
+    MOZ_ASSERT(classification == eMixedScript);
+    // If the content is active content, and the pref says active content should
+    // be blocked, block it unless the user has choosen to override the pref
+    if (!StaticPrefs::security_mixed_content_block_active_content() ||
+        allowMixedContent) {
+      *aDecision = nsIContentPolicy::ACCEPT;
+      // User has already overriden the pref and the root is not https;
+      // mixed active content was allowed on an https subframe.
+      newState |= nsIWebProgressListener::STATE_LOADED_MIXED_ACTIVE_CONTENT;
+    } else {
+      // User has not overriden the pref by Disabling protection. Reject the
+      // request and update the security state.
+      *aDecision = nsIContentPolicy::REJECT_REQUEST;
+      MOZ_LOG(sMCBLog, LogLevel::Verbose,
+              ("  -> decision: Request will be rejected because the content is "
+               "active "
+               "content (blocked by pref "
+               "security.mixed_content.block_active_content)."));
+      // The user has not overriden the pref, so make sure they still have an
+      // option by calling nativeDocShell which will invoke the doorhanger
+      newState |= nsIWebProgressListener::STATE_BLOCKED_MIXED_ACTIVE_CONTENT;
+    }
+  }
+
+  // To avoid duplicate errors on the console, we do not report blocked
+  // preloads to the console.
+  if (!isPreload && aReportError) {
+    LogMixedContentMessage(classification, aContentLocation, topWC->Id(),
+                           (*aDecision == nsIContentPolicy::REJECT_REQUEST)
+                               ? eBlocked
+                               : eUserOverride,
+                           requestingLocation);
+  }
+
+  // Notify the top WindowContext of the flags we've computed, and it
+  // will handle updating any relevant security UI.
+  topWC->AddSecurityState(newState);
+  return NS_OK;
+}
+
+bool nsMixedContentBlocker::URISafeToBeLoadedInSecureContext(nsIURI* aURI) {
+  /* Returns a bool if the URI can be loaded as a sub resource safely.
+   *
+   * Check Protocol Flags to determine if scheme is safe to load:
+   * URI_DOES_NOT_RETURN_DATA - e.g.
+   *   "mailto"
+   * URI_IS_LOCAL_RESOURCE - e.g.
+   *   "data",
+   *   "resource",
+   *   "moz-icon"
+   * URI_INHERITS_SECURITY_CONTEXT - e.g.
+   *   "javascript"
+   * URI_IS_POTENTIALLY_TRUSTWORTHY - e.g.
+   *   "https",
+   *   "moz-safe-about"
+   *
+   */
+  bool schemeLocal = false;
+  bool schemeNoReturnData = false;
+  bool schemeInherits = false;
+  bool schemeSecure = false;
+  if (NS_FAILED(NS_URIChainHasFlags(
+          aURI, nsIProtocolHandler::URI_IS_LOCAL_RESOURCE, &schemeLocal)) ||
+      NS_FAILED(NS_URIChainHasFlags(
+          aURI, nsIProtocolHandler::URI_DOES_NOT_RETURN_DATA,
+          &schemeNoReturnData)) ||
+      NS_FAILED(NS_URIChainHasFlags(
+          aURI, nsIProtocolHandler::URI_INHERITS_SECURITY_CONTEXT,
+          &schemeInherits)) ||
+      NS_FAILED(NS_URIChainHasFlags(
+          aURI, nsIProtocolHandler::URI_IS_POTENTIALLY_TRUSTWORTHY,
+          &schemeSecure))) {
+    return false;
+  }
+
+  MOZ_LOG(sMCBLog, LogLevel::Verbose,
+          ("  - URISafeToBeLoadedInSecureContext:"));
+  MOZ_LOG(sMCBLog, LogLevel::Verbose, ("    - schemeLocal: %i", schemeLocal));
+  MOZ_LOG(sMCBLog, LogLevel::Verbose,
+          ("    - schemeNoReturnData: %i", schemeNoReturnData));
+  MOZ_LOG(sMCBLog, LogLevel::Verbose,
+          ("    - schemeInherits: %i", schemeInherits));
+  MOZ_LOG(sMCBLog, LogLevel::Verbose, ("    - schemeSecure: %i", schemeSecure));
+  return (schemeLocal || schemeNoReturnData || schemeInherits || schemeSecure);
+}
+
+NS_IMETHODIMP
+nsMixedContentBlocker::ShouldProcess(nsIURI* aContentLocation,
+                                     nsILoadInfo* aLoadInfo,
+                                     int16_t* aDecision) {
+  if (!aContentLocation) {
+    // aContentLocation may be null when a plugin is loading without an
+    // associated URI resource
+    if (aLoadInfo->GetExternalContentPolicyType() ==
+        ExtContentPolicyType::TYPE_OBJECT) {
+      *aDecision = ACCEPT;
+      return NS_OK;
+    }
+
+    NS_SetRequestBlockingReason(aLoadInfo,
+                                nsILoadInfo::BLOCKING_REASON_MIXED_BLOCKED);
+    *aDecision = REJECT_REQUEST;
+    return NS_ERROR_FAILURE;
+  }
+
+  return ShouldLoad(aContentLocation, aLoadInfo, aDecision);
+}
+
+// Record information on when HSTS would have made mixed content not mixed
+// content (regardless of whether it was actually blocked)
+void nsMixedContentBlocker::AccumulateMixedContentHSTS(
+    nsIURI* aURI, bool aActive, const OriginAttributes& aOriginAttributes) {
+  // This method must only be called in the parent, because
+  // nsSiteSecurityService is only available in the parent
+  if (!XRE_IsParentProcess()) {
+    MOZ_ASSERT(false);
+    return;
+  }
+
+  bool hsts;
+  nsresult rv;
+  nsCOMPtr<nsISiteSecurityService> sss =
+      do_GetService(NS_SSSERVICE_CONTRACTID, &rv);
+  if (NS_FAILED(rv)) {
+    return;
+  }
+  rv = sss->IsSecureURI(aURI, aOriginAttributes, &hsts);
+  if (NS_FAILED(rv)) {
+    return;
+  }
+
+  // states: would upgrade, would prime, hsts info cached
+  // active, passive
+  //
+  if (!aActive) {
+    if (!hsts) {
+      Telemetry::Accumulate(Telemetry::MIXED_CONTENT_HSTS,
+                            MCB_HSTS_PASSIVE_NO_HSTS);
+    } else {
+      Telemetry::Accumulate(Telemetry::MIXED_CONTENT_HSTS,
+                            MCB_HSTS_PASSIVE_WITH_HSTS);
+    }
+  } else {
+    if (!hsts) {
+      Telemetry::Accumulate(Telemetry::MIXED_CONTENT_HSTS,
+                            MCB_HSTS_ACTIVE_NO_HSTS);
+    } else {
+      Telemetry::Accumulate(Telemetry::MIXED_CONTENT_HSTS,
+                            MCB_HSTS_ACTIVE_WITH_HSTS);
+    }
+  }
+}