Add system HTTP proxy support to libsignal-net.

Co-authored-by: Cody Henthorne <cody@signal.org>

app/src/androidTest/java/org/thoughtcrime/securesms/dependencies/InstrumentationApplicationDependencyProvider.kt

@@ -97,6 +97,7 @@ class InstrumentationApplicationDependencyProvider(val application: Application,
       networkInterceptors = emptyList(),
       dns = Optional.of(SignalServiceNetworkAccess.DNS),
       signalProxy = Optional.empty(),
+      systemHttpProxy = Optional.empty(),
       zkGroupServerPublicParams = Base64.decode(BuildConfig.ZKGROUP_SERVER_PUBLIC_PARAMS),
       genericServerPublicParams = Base64.decode(BuildConfig.GENERIC_SERVER_PUBLIC_PARAMS),
       backupServerPublicParams = Base64.decode(BuildConfig.BACKUP_SERVER_PUBLIC_PARAMS),

app/src/main/java/org/thoughtcrime/securesms/dependencies/AppDependencies.kt

@@ -7,6 +7,7 @@ import okhttp3.OkHttpClient
 import org.signal.core.util.billing.BillingApi
 import org.signal.core.util.concurrent.DeadlockDetector
 import org.signal.core.util.concurrent.LatestValueObservable
+import org.signal.core.util.orNull
 import org.signal.core.util.resettableLazy
 import org.signal.libsignal.net.Network
 import org.signal.libsignal.zkgroup.profiles.ClientZkProfileOperations
@@ -16,6 +17,7 @@ import org.thoughtcrime.securesms.components.TypingStatusSender
 import org.thoughtcrime.securesms.crypto.storage.SignalServiceDataStoreImpl
 import org.thoughtcrime.securesms.database.DatabaseObserver
 import org.thoughtcrime.securesms.database.PendingRetryReceiptCache
+import org.thoughtcrime.securesms.dependencies.AppDependencies.authWebSocket
 import org.thoughtcrime.securesms.groups.GroupsV2Authorization
 import org.thoughtcrime.securesms.jobmanager.JobManager
 import org.thoughtcrime.securesms.megaphone.MegaphoneRepository
@@ -378,6 +380,16 @@ object AppDependencies {
     networkModule.openConnections()
   }
 
+  fun onSystemHttpProxyChange(host: String?, port: Int?): Boolean {
+    val currentSystemProxy = signalServiceNetworkAccess.getConfiguration().systemHttpProxy.orNull()
+    return if (currentSystemProxy?.host != host || currentSystemProxy?.port != port) {
+      resetNetwork()
+      true
+    } else {
+      false
+    }
+  }
+
   interface Provider {
     fun providePushServiceSocket(signalServiceConfiguration: SignalServiceConfiguration, groupsV2Operations: GroupsV2Operations): PushServiceSocket
     fun provideGroupsV2Operations(signalServiceConfiguration: SignalServiceConfiguration): GroupsV2Operations

app/src/main/java/org/thoughtcrime/securesms/messages/IncomingMessageObserver.kt

@@ -4,6 +4,7 @@ import android.app.Application
 import android.app.Service
 import android.content.Context
 import android.content.Intent
+import android.net.ProxyInfo
 import android.os.IBinder
 import androidx.annotation.VisibleForTesting
 import androidx.core.app.NotificationCompat
@@ -86,7 +87,10 @@ class IncomingMessageObserver(private val context: Application, private val auth
 
   private val lock: ReentrantLock = ReentrantLock()
   private val connectionNecessarySemaphore = Semaphore(0)
-  private val networkConnectionListener = NetworkConnectionListener(context) { isNetworkUnavailable ->
+  private var previousProxyInfo: ProxyInfo? = null
+  private val networkConnectionListener = NetworkConnectionListener(
+    context,
+    { isNetworkUnavailable ->
       lock.withLock {
         AppDependencies.libsignalNetwork.onNetworkChange()
         if (isNetworkUnavailable()) {
@@ -95,7 +99,17 @@ class IncomingMessageObserver(private val context: Application, private val auth
         }
         connectionNecessarySemaphore.release()
       }
+    },
+    { proxyInfo ->
+      if (proxyInfo != previousProxyInfo) {
+        val networkReset = AppDependencies.onSystemHttpProxyChange(proxyInfo?.host, proxyInfo?.port)
+        if (networkReset) {
+          Log.i(TAG, "System proxy configuration changed, network reset.")
         }
+      }
+      previousProxyInfo = proxyInfo
+    }
+  )
 
   private val messageContentProcessor = MessageContentProcessor(context)
 

app/src/main/java/org/thoughtcrime/securesms/messages/NetworkConnectionListener.kt

@@ -10,7 +10,9 @@ import android.content.Context
 import android.content.Intent
 import android.content.IntentFilter
 import android.net.ConnectivityManager
+import android.net.LinkProperties
 import android.net.Network
+import android.net.ProxyInfo
 import android.os.Build
 import org.signal.core.util.logging.Log
 import org.thoughtcrime.securesms.jobmanager.impl.NetworkConstraint
@@ -24,7 +26,7 @@ import org.thoughtcrime.securesms.util.ServiceUtil
  * API 28+ only runs on lost networks, so it provides a conditional that's always true because that is guaranteed by the call site.
  * Earlier versions use [NetworkConstraint.isMet] to query the current network state upon receiving the broadcast.
  */
-class NetworkConnectionListener(private val context: Context, private val onNetworkLost: (() -> Boolean) -> Unit) {
+class NetworkConnectionListener(private val context: Context, private val onNetworkLost: (() -> Boolean) -> Unit, private val onProxySettingsChanged: ((ProxyInfo?) -> Unit)) {
   companion object {
     private val TAG = Log.tag(NetworkConnectionListener::class.java)
   }
@@ -55,6 +57,12 @@ class NetworkConnectionListener(private val context: Context, private val onNetw
       Log.d(TAG, "ConnectivityManager.NetworkCallback onLost()")
       onNetworkLost { true }
     }
+
+    override fun onLinkPropertiesChanged(network: Network, linkProperties: LinkProperties) {
+      super.onLinkPropertiesChanged(network, linkProperties)
+      Log.d(TAG, "ConnectivityManager.NetworkCallback onLinkPropertiesChanged()")
+      onProxySettingsChanged(linkProperties.httpProxy)
+    }
   }
 
   private val connectionReceiver = object : BroadcastReceiver() {

app/src/main/java/org/thoughtcrime/securesms/push/SignalServiceNetworkAccess.kt

@@ -1,6 +1,9 @@
 package org.thoughtcrime.securesms.push
 
 import android.content.Context
+import android.net.ConnectivityManager
+import android.os.Build
+import androidx.core.content.ContextCompat
 import com.google.i18n.phonenumbers.PhoneNumberUtil
 import okhttp3.CipherSuite
 import okhttp3.ConnectionSpec
@@ -20,6 +23,7 @@ import org.thoughtcrime.securesms.net.SequentialDns
 import org.thoughtcrime.securesms.net.StandardUserAgentInterceptor
 import org.thoughtcrime.securesms.net.StaticDns
 import org.whispersystems.signalservice.api.push.TrustStore
+import org.whispersystems.signalservice.internal.configuration.HttpProxy
 import org.whispersystems.signalservice.internal.configuration.SignalCdnUrl
 import org.whispersystems.signalservice.internal.configuration.SignalCdsiUrl
 import org.whispersystems.signalservice.internal.configuration.SignalServiceConfiguration
@@ -28,6 +32,7 @@ import org.whispersystems.signalservice.internal.configuration.SignalStorageUrl
 import org.whispersystems.signalservice.internal.configuration.SignalSvr2Url
 import java.io.IOException
 import java.util.Optional
+import android.net.Proxy as AndroidProxy
 
 /**
  * Provides a [SignalServiceConfiguration] to be used with our service layer.
@@ -133,6 +138,28 @@ class SignalServiceNetworkAccess(context: Context) {
       .build()
 
     private val APP_CONNECTION_SPEC = ConnectionSpec.MODERN_TLS
+
+    @Suppress("DEPRECATION")
+    private fun getSystemHttpProxy(context: Context): HttpProxy? {
+      return if (Build.VERSION.SDK_INT >= 23) {
+        val connectivityManager = ContextCompat.getSystemService(context, ConnectivityManager::class.java) ?: return null
+
+        connectivityManager
+          .activeNetwork
+          ?.let { connectivityManager.getLinkProperties(it)?.httpProxy }
+          ?.takeIf { !it.exclusionList.contains(BuildConfig.SIGNAL_URL.stripProtocol()) }
+          ?.let { proxy -> HttpProxy(proxy.host, proxy.port) }
+      } else {
+        val host: String? = AndroidProxy.getHost(context)
+        val port: Int = AndroidProxy.getPort(context)
+
+        if (host != null) {
+          HttpProxy(host, port)
+        } else {
+          null
+        }
+      }
+    }
   }
 
   private val serviceTrustStore: TrustStore = SignalServiceTrustStore(context)
@@ -187,6 +214,7 @@ class SignalServiceNetworkAccess(context: Context) {
     networkInterceptors = interceptors,
     dns = Optional.of(DNS),
     signalProxy = Optional.empty(),
+    systemHttpProxy = Optional.empty(),
     zkGroupServerPublicParams = zkGroupServerPublicParams,
     genericServerPublicParams = genericServerPublicParams,
     backupServerPublicParams = backupServerPublicParams,
@@ -246,6 +274,7 @@ class SignalServiceNetworkAccess(context: Context) {
     networkInterceptors = interceptors,
     dns = Optional.of(DNS),
     signalProxy = if (SignalStore.proxy.isProxyEnabled) Optional.ofNullable(SignalStore.proxy.proxy) else Optional.empty(),
+    systemHttpProxy = Optional.ofNullable(getSystemHttpProxy(context)),
     zkGroupServerPublicParams = zkGroupServerPublicParams,
     genericServerPublicParams = genericServerPublicParams,
     backupServerPublicParams = backupServerPublicParams,
@@ -316,6 +345,7 @@ class SignalServiceNetworkAccess(context: Context) {
       networkInterceptors = interceptors,
       dns = Optional.of(DNS),
       signalProxy = Optional.empty(),
+      systemHttpProxy = Optional.empty(),
       zkGroupServerPublicParams = zkGroupServerPublicParams,
       genericServerPublicParams = genericServerPublicParams,
       backupServerPublicParams = backupServerPublicParams,

libsignal-service/src/main/java/org/whispersystems/signalservice/internal/configuration/HttpProxy.kt

@@ -0,0 +1,6 @@
+package org.whispersystems.signalservice.internal.configuration
+
+/**
+ * HTTP Proxy configuration from Android OS configuration.
+ */
+class HttpProxy(val host: String, val port: Int)

libsignal-service/src/main/java/org/whispersystems/signalservice/internal/configuration/SignalServiceConfiguration.kt

@@ -17,6 +17,7 @@ data class SignalServiceConfiguration(
   val networkInterceptors: List<Interceptor>,
   val dns: Optional<Dns>,
   val signalProxy: Optional<SignalProxy>,
+  val systemHttpProxy: Optional<HttpProxy>,
   val zkGroupServerPublicParams: ByteArray,
   val genericServerPublicParams: ByteArray,
   val backupServerPublicParams: ByteArray,

libsignal-service/src/main/java/org/whispersystems/signalservice/internal/websocket/LibSignalNetworkExtensions.kt

@@ -30,18 +30,29 @@ fun Network.transformAndSetRemoteConfig(remoteConfig: Map<String, Any>) {
  * Helper method to apply settings from the SignalServiceConfiguration.
  */
 fun Network.applyConfiguration(config: SignalServiceConfiguration) {
-  val proxy = config.signalProxy.orNull()
+  val signalProxy = config.signalProxy.orNull()
+  val systemHttpProxy = config.systemHttpProxy.orNull()
 
-  if (proxy == null) {
-    this.clearProxy()
-  } else {
+  when {
+    (signalProxy != null) -> {
       try {
-      this.setProxy(proxy.host, proxy.port)
+        this.setProxy(signalProxy.host, signalProxy.port)
       } catch (e: IOException) {
         Log.e(TAG, "Invalid proxy configuration set! Failing connections until changed.")
         this.setInvalidProxy()
       }
     }
+    (systemHttpProxy != null) -> {
+      try {
+        this.setProxy("http", systemHttpProxy.host, systemHttpProxy.port, "", "")
+      } catch (e: IOException) {
+        // The Android settings screen where this is set explicitly calls out that apps are allowed to
+        //  ignore the HTTP Proxy setting, so if using the specified proxy would cause us to break, let's
+        //  try just ignoring it and seeing if that still lets us connect.
+        Log.w(TAG, "Failed to set system HTTP proxy, ignoring and continuing...")
+      }
+    }
+  }
 
   this.setCensorshipCircumventionEnabled(config.censored)
 }