Bug 1908056 - Add media.devices.enumerate.legacy.allowlist exception for slack. r=dbaker

Differential Revision: https://phabricator.services.mozilla.com/D224367

dom/media/MediaDevices.cpp

@@ -231,6 +231,21 @@ void MediaDevices::MaybeResumeDeviceExposure() {
   mHaveUnprocessedDeviceListChange = false;
 }
 
+static bool IsLegacyMode(nsPIDOMWindowInner* window) {
+  if (StaticPrefs::media_devices_enumerate_legacy_enabled()) {
+    return true;
+  }
+  if (window->GetDocumentURI()) {
+    nsAutoCString host;
+    window->GetDocumentURI()->GetAsciiHost(host);
+    if (media::HostnameInPref("media.devices.enumerate.legacy.allowlist",
+                              host)) {
+      return true;
+    }
+  }
+  return false;
+}
+
 RefPtr<MediaDeviceSetRefCnt> MediaDevices::FilterExposedDevices(
     const MediaDeviceSet& aDevices) const {
   nsPIDOMWindowInner* window = GetOwnerWindow();
@@ -250,7 +265,7 @@ RefPtr<MediaDeviceSetRefCnt> MediaDevices::FilterExposedDevices(
       !Preferences::GetBool("media.setsinkid.enabled") ||
       !FeaturePolicyUtils::IsFeatureAllowed(doc, u"speaker-selection"_ns);
 
-  bool legacy = StaticPrefs::media_devices_enumerate_legacy_enabled();
+  bool legacy = IsLegacyMode(window);
   bool outputIsDefault = true;  // First output is the default.
   bool haveDefaultOutput = false;
   nsTHashSet<nsString> exposedMicrophoneGroupIds;
@@ -467,7 +482,7 @@ void MediaDevices::ResolveEnumerateDevicesPromise(
   nsCOMPtr<nsPIDOMWindowInner> window = GetOwnerWindow();
   auto windowId = window->WindowID();
   nsTArray<RefPtr<MediaDeviceInfo>> infos;
-  bool legacy = StaticPrefs::media_devices_enumerate_legacy_enabled();
+  bool legacy = IsLegacyMode(window);
   bool capturePermitted =
       legacy &&
       MediaManager::Get()->IsActivelyCapturingOrHasAPermission(windowId);

dom/media/systemservices/MediaUtils.cpp

@@ -7,10 +7,64 @@
 #include "MediaUtils.h"
 
 #include "mozilla/AppShutdown.h"
+#include "mozilla/Preferences.h"
 #include "mozilla/Services.h"
+#include "nsNetUtil.h"
 
 namespace mozilla::media {
 
+bool HostnameInPref(const char* aPref, const nsCString& aHostName) {
+  auto HostInDomain = [](const nsCString& aHost, const nsCString& aPattern) {
+    int32_t patternOffset = 0;
+    int32_t hostOffset = 0;
+
+    // Act on '*.' wildcard in the left-most position in a domain pattern.
+    if (StringBeginsWith(aPattern, nsCString("*."))) {
+      patternOffset = 2;
+
+      // Ignore the lowest level sub-domain for the hostname.
+      hostOffset = aHost.FindChar('.') + 1;
+
+      if (hostOffset <= 1) {
+        // Reject a match between a wildcard and a TLD or '.foo' form.
+        return false;
+      }
+    }
+
+    nsDependentCString hostRoot(aHost, hostOffset);
+    return hostRoot.EqualsIgnoreCase(aPattern.BeginReading() + patternOffset);
+  };
+
+  nsCString domainList;
+  nsresult rv = Preferences::GetCString(aPref, domainList);
+
+  if (NS_FAILED(rv)) {
+    return false;
+  }
+
+  domainList.StripWhitespace();
+
+  if (domainList.IsEmpty() || aHostName.IsEmpty()) {
+    return false;
+  }
+
+  // Test each domain name in the comma separated list
+  // after converting from UTF8 to ASCII. Each domain
+  // must match exactly or have a single leading '*.' wildcard.
+  for (const nsACString& each : domainList.Split(',')) {
+    nsCString domainPattern;
+    rv = NS_DomainToASCIIAllowAnyGlyphfulASCII(each, domainPattern);
+    if (NS_SUCCEEDED(rv)) {
+      if (HostInDomain(aHostName, domainPattern)) {
+        return true;
+      }
+    } else {
+      NS_WARNING("Failed to convert UTF-8 host to ASCII");
+    }
+  }
+  return false;
+}
+
 nsCOMPtr<nsIAsyncShutdownClient> GetShutdownBarrier() {
   nsCOMPtr<nsIAsyncShutdownService> svc = services::GetAsyncShutdownService();
   if (!svc) {

dom/media/systemservices/MediaUtils.h

@@ -28,6 +28,12 @@ class nsIEventTarget;
 
 namespace mozilla::media {
 
+/* Utility function, given a string pref and an URI, returns whether or not
+ * the URI occurs in the pref. Wildcards are supported (e.g. *.example.com)
+ * and multiple hostnames can be present, separated by commas.
+ */
+bool HostnameInPref(const char* aPrefList, const nsCString& aHostName);
+
 /* media::NewRunnableFrom() - Create a Runnable from a lambda.
  *
  * Passing variables (closures) to an async function is clunky with Runnable:

dom/media/webrtc/jsapi/PeerConnectionImpl.cpp

@@ -53,6 +53,7 @@
 #include "mozilla/IntegerPrintfMacros.h"
 #include "mozilla/Sprintf.h"
 #include "mozilla/StaticPrefs_media.h"
+#include "mozilla/media/MediaUtils.h"
 
 #ifdef XP_WIN
 // We need to undef the MS macro for Document::CreateEvent
@@ -396,9 +397,9 @@ PeerConnectionImpl::PeerConnectionImpl(const GlobalObject* aGlobal)
                                              mEffectiveTLDPlus1);
       }
 
-      mRtxIsAllowed = !HostnameInPref(
+      mRtxIsAllowed = !media::HostnameInPref(
           "media.peerconnection.video.use_rtx.blocklist", mHostname);
-      mDuplicateFingerprintQuirk = HostnameInPref(
+      mDuplicateFingerprintQuirk = media::HostnameInPref(
           "media.peerconnection.sdp.quirk.duplicate_fingerprint.allowlist",
           mHostname);
     }
@@ -2160,60 +2161,6 @@ void PeerConnectionImpl::DumpPacket_m(size_t level, dom::mozPacketDumpType type,
   mPCObserver->OnPacket(level, type, sending, arrayBuffer, jrv);
 }
 
-bool PeerConnectionImpl::HostnameInPref(const char* aPref,
-                                        const nsCString& aHostName) {
-  auto HostInDomain = [](const nsCString& aHost, const nsCString& aPattern) {
-    int32_t patternOffset = 0;
-    int32_t hostOffset = 0;
-
-    // Act on '*.' wildcard in the left-most position in a domain pattern.
-    if (StringBeginsWith(aPattern, nsCString("*."))) {
-      patternOffset = 2;
-
-      // Ignore the lowest level sub-domain for the hostname.
-      hostOffset = aHost.FindChar('.') + 1;
-
-      if (hostOffset <= 1) {
-        // Reject a match between a wildcard and a TLD or '.foo' form.
-        return false;
-      }
-    }
-
-    nsDependentCString hostRoot(aHost, hostOffset);
-    return hostRoot.EqualsIgnoreCase(aPattern.BeginReading() + patternOffset);
-  };
-
-  nsCString domainList;
-  nsresult rv = Preferences::GetCString(aPref, domainList);
-
-  if (NS_FAILED(rv)) {
-    return false;
-  }
-
-  domainList.StripWhitespace();
-
-  if (domainList.IsEmpty() || aHostName.IsEmpty()) {
-    return false;
-  }
-
-  // Test each domain name in the comma separated list
-  // after converting from UTF8 to ASCII. Each domain
-  // must match exactly or have a single leading '*.' wildcard.
-  for (const nsACString& each : domainList.Split(',')) {
-    nsCString domainPattern;
-    rv = NS_DomainToASCIIAllowAnyGlyphfulASCII(each, domainPattern);
-    if (NS_SUCCEEDED(rv)) {
-      if (HostInDomain(aHostName, domainPattern)) {
-        return true;
-      }
-    } else {
-      NS_WARNING("Failed to convert UTF-8 host to ASCII");
-    }
-  }
-
-  return false;
-}
-
 nsresult PeerConnectionImpl::EnablePacketDump(unsigned long level,
                                               dom::mozPacketDumpType type,
                                               bool sending) {
@@ -4452,7 +4399,7 @@ bool PeerConnectionImpl::GetPrefObfuscateHostAddresses() const {
       "media.peerconnection.ice.obfuscate_host_addresses", false);
   obfuscate_host_addresses &=
       !MediaManager::Get()->IsActivelyCapturingOrHasAPermission(winId);
-  obfuscate_host_addresses &= !PeerConnectionImpl::HostnameInPref(
+  obfuscate_host_addresses &= !media::HostnameInPref(
       "media.peerconnection.ice.obfuscate_host_addresses.blocklist", mHostname);
   obfuscate_host_addresses &= XRE_IsContentProcess();
 

dom/media/webrtc/jsapi/PeerConnectionImpl.h

@@ -534,11 +534,6 @@ class PeerConnectionImpl final
     return mTimestampMaker;
   }
 
-  // Utility function, given a string pref and an URI, returns whether or not
-  // the URI occurs in the pref. Wildcards are supported (e.g. *.example.com)
-  // and multiple hostnames can be present, separated by commas.
-  static bool HostnameInPref(const char* aPrefList, const nsCString& aHostName);
-
   void StampTimecard(const char* aEvent);
 
   bool RelayOnly() const {

dom/media/webrtc/tests/mochitests/test_enumerateDevices_legacy.html

@@ -47,12 +47,9 @@ function validateDevice({kind, label, deviceId, groupId}) {
   isnot(groupId, "", "groupId must be present.");
 }
 
-runTest(async () => {
-  await pushPrefs(["media.navigator.streams.fake", true],
-                  ["media.devices.enumerate.legacy.enabled", true]);
-
-  // Validate enumerated devices before gUM (legacy).
+// Validate enumerated devices before gUM (legacy).
 
+async function testLegacyEnumerateDevices() {
   let devices = await navigator.mediaDevices.enumerateDevices();
   ok(devices.length, "At least one device found");
   const jsoned = JSON.parse(JSON.stringify(devices));
@@ -140,7 +137,17 @@ runTest(async () => {
                   ["media.video_loopback_dev", "none"]);
   devices = await navigator.mediaDevices.enumerateDevices();
   is(devices.length, 0, "No devices");
+}
+
+runTest(async () => {
+  await withPrefs([["media.navigator.streams.fake", true],
+                   ["media.devices.enumerate.legacy.allowlist", "example.com,*.example.com"]],
+                  testLegacyEnumerateDevices);
+  await withPrefs([["media.navigator.streams.fake", true],
+                   ["media.devices.enumerate.legacy.enabled", true]],
+                  testLegacyEnumerateDevices);
 });
+
 </script>
 </pre>
 </body>

modules/libpref/init/StaticPrefList.yaml

@@ -11491,6 +11491,14 @@
   value: false
   mirror: always
 
+# Turns on legacy (non-spec) exposure of camera and microphone information
+# from enumerateDevices and devicechange ahead of successful getUserMedia
+# calls only for certain domains (ignored if above pref is true).
+- name: media.devices.enumerate.legacy.allowlist
+  type: String
+  value: "slack.com,*.slack.com"
+  mirror: never
+
 # WebRTC prefs follow
 
 # Enables auto refresh of peerconnection stats by default