TransportInfo: Add a generic redaction mechanism

This replaces the existing mechanism for redacting location sensitive
fields with a more extensible mechanism. Currently supported redactions
are for the following permissions:
i. ACCESS_FINE_LOCATION
ii. LOCAL_MAC_ADDRESS
iii. NETWORK_SETTINGS

Also, removed WifiInfo from ConnectivityServiceTest to reduce cross
dependencies on wifi code.

Bug: 156867433
Bug: 162602799
Test: atest android.net
Test: atest com.android.server
Change-Id: I2bb980c624667a55c1383f13ab71b9b97ed6eeab

1 files changed, 96 insertions, 15 deletions

diff --git a/framework/src/android/net/NetworkCapabilities.java b/framework/src/android/net/NetworkCapabilities.java
index 182bc7141a..add9a15db4 100644
--- a/framework/src/android/net/NetworkCapabilities.java
+++ b/framework/src/android/net/NetworkCapabilities.java
@@ -19,6 +19,7 @@ package android.net;
 import static com.android.internal.annotations.VisibleForTesting.Visibility.PRIVATE;
 
 import android.annotation.IntDef;
+import android.annotation.LongDef;
 import android.annotation.NonNull;
 import android.annotation.Nullable;
 import android.annotation.RequiresPermission;
@@ -65,6 +66,68 @@ import java.util.StringJoiner;
 public final class NetworkCapabilities implements Parcelable {
     private static final String TAG = "NetworkCapabilities";
 
+    /**
+     * Mechanism to support redaction of fields in NetworkCapabilities that are guarded by specific
+     * app permissions.
+     **/
+    /**
+     * Don't redact any fields since the receiving app holds all the necessary permissions.
+     *
+     * @hide
+     */
+    @SystemApi(client = SystemApi.Client.MODULE_LIBRARIES)
+    public static final long REDACT_NONE = 0;
+
+    /**
+     * Redact any fields that need {@link android.Manifest.permission#ACCESS_FINE_LOCATION}
+     * permission since the receiving app does not hold this permission or the location toggle
+     * is off.
+     *
+     * @see android.Manifest.permission#ACCESS_FINE_LOCATION
+     * @hide
+     */
+    @SystemApi(client = SystemApi.Client.MODULE_LIBRARIES)
+    public static final long REDACT_FOR_ACCESS_FINE_LOCATION = 1 << 0;
+
+    /**
+     * Redact any fields that need {@link android.Manifest.permission#LOCAL_MAC_ADDRESS}
+     * permission since the receiving app does not hold this permission.
+     *
+     * @see android.Manifest.permission#LOCAL_MAC_ADDRESS
+     * @hide
+     */
+    @SystemApi(client = SystemApi.Client.MODULE_LIBRARIES)
+    public static final long REDACT_FOR_LOCAL_MAC_ADDRESS = 1 << 1;
+
+    /**
+     *
+     * Redact any fields that need {@link android.Manifest.permission#NETWORK_SETTINGS}
+     * permission since the receiving app does not hold this permission.
+     *
+     * @see android.Manifest.permission#NETWORK_SETTINGS
+     * @hide
+     */
+    @SystemApi(client = SystemApi.Client.MODULE_LIBRARIES)
+    public static final long REDACT_FOR_NETWORK_SETTINGS = 1 << 2;
+
+    /**
+     * Redact all fields in this object that require any relevant permission.
+     * @hide
+     */
+    @SystemApi(client = SystemApi.Client.MODULE_LIBRARIES)
+    public static final long REDACT_ALL = -1L;
+
+    /** @hide */
+    @LongDef(flag = true, prefix = { "REDACT_" }, value = {
+            REDACT_NONE,
+            REDACT_FOR_ACCESS_FINE_LOCATION,
+            REDACT_FOR_LOCAL_MAC_ADDRESS,
+            REDACT_FOR_NETWORK_SETTINGS,
+            REDACT_ALL
+    })
+    @Retention(RetentionPolicy.SOURCE)
+    public @interface RedactionType {}
+
     // Set to true when private DNS is broken.
     private boolean mPrivateDnsBroken;
 
@@ -79,32 +142,31 @@ public final class NetworkCapabilities implements Parcelable {
     private String mRequestorPackageName;
 
     /**
-     * Indicates whether parceling should preserve fields that are set based on permissions of
-     * the process receiving the {@link NetworkCapabilities}.
+     * Indicates what fields should be redacted from this instance.
      */
-    private final boolean mParcelLocationSensitiveFields;
+    private final @RedactionType long mRedactions;
 
     public NetworkCapabilities() {
-        mParcelLocationSensitiveFields = false;
+        mRedactions = REDACT_ALL;
         clearAll();
         mNetworkCapabilities = DEFAULT_CAPABILITIES;
     }
 
     public NetworkCapabilities(NetworkCapabilities nc) {
-        this(nc, false /* parcelLocationSensitiveFields */);
+        this(nc, REDACT_ALL);
     }
 
     /**
      * Make a copy of NetworkCapabilities.
      *
      * @param nc Original NetworkCapabilities
-     * @param parcelLocationSensitiveFields Whether to parcel location sensitive data or not.
+     * @param redactions bitmask of redactions that needs to be performed on this new instance of
+     *                   {@link NetworkCapabilities}.
      * @hide
      */
-    @SystemApi
-    public NetworkCapabilities(
-            @Nullable NetworkCapabilities nc, boolean parcelLocationSensitiveFields) {
-        mParcelLocationSensitiveFields = parcelLocationSensitiveFields;
+    @SystemApi(client = SystemApi.Client.MODULE_LIBRARIES)
+    public NetworkCapabilities(@Nullable NetworkCapabilities nc, @RedactionType long redactions) {
+        mRedactions = redactions;
         if (nc != null) {
             set(nc);
         }
@@ -116,11 +178,13 @@ public final class NetworkCapabilities implements Parcelable {
      * @hide
      */
     public void clearAll() {
-        // Ensures that the internal copies maintained by the connectivity stack does not set
-        // this bit.
-        if (mParcelLocationSensitiveFields) {
+        // Ensures that the internal copies maintained by the connectivity stack does not set it to
+        // anything other than |REDACT_ALL|.
+        if (mRedactions != REDACT_ALL) {
+            // This is needed because the current redaction mechanism relies on redaction while
+            // parceling.
             throw new UnsupportedOperationException(
-                    "Cannot clear NetworkCapabilities when parcelLocationSensitiveFields is set");
+                    "Cannot clear NetworkCapabilities when mRedactions is set");
         }
         mNetworkCapabilities = mTransportTypes = mUnwantedNetworkCapabilities = 0;
         mLinkUpBandwidthKbps = mLinkDownBandwidthKbps = LINK_BANDWIDTH_UNSPECIFIED;
@@ -150,7 +214,7 @@ public final class NetworkCapabilities implements Parcelable {
         mLinkDownBandwidthKbps = nc.mLinkDownBandwidthKbps;
         mNetworkSpecifier = nc.mNetworkSpecifier;
         if (nc.getTransportInfo() != null) {
-            setTransportInfo(nc.getTransportInfo().makeCopy(mParcelLocationSensitiveFields));
+            setTransportInfo(nc.getTransportInfo().makeCopy(mRedactions));
         } else {
             setTransportInfo(null);
         }
@@ -2351,6 +2415,23 @@ public final class NetworkCapabilities implements Parcelable {
     }
 
     /**
+     * Returns a bitmask of all the applicable redactions (based on the permissions held by the
+     * receiving app) to be performed on this object.
+     *
+     * @return bitmask of redactions applicable on this instance.
+     * @hide
+     */
+    public @RedactionType long getApplicableRedactions() {
+        // Currently, there are no fields redacted in NetworkCapabilities itself, so we just
+        // passthrough the redactions required by the embedded TransportInfo. If this changes
+        // in the future, modify this method.
+        if (mTransportInfo == null) {
+            return NetworkCapabilities.REDACT_NONE;
+        }
+        return mTransportInfo.getApplicableRedactions();
+    }
+
+    /**
      * Builder class for NetworkCapabilities.
      *
      * This class is mainly for for {@link NetworkAgent} instances to use. Many fields in