Add bpf map and lock for UidOwnerMap

This commit is a preparation for replacing JNI codes that modify
UidOwnerMap by Java.

Bug: 217624062
Test: atest BpfNetMapsTest HostsideRestrictBackgroundNetworkTests
android.net.cts.ConnectivityManagerTest#testFirewallBlocking

Change-Id: Ie595cf1f77a3ed86addbcdaea1a1be972e0265b3
diff --git a/service/src/com/android/server/BpfNetMaps.java b/service/src/com/android/server/BpfNetMaps.java
index 5650e31..3a5fc06 100644
--- a/service/src/com/android/server/BpfNetMaps.java
+++ b/service/src/com/android/server/BpfNetMaps.java
@@ -35,6 +35,7 @@
 import android.util.Log;
 import android.util.SparseLongArray;
 
+import com.android.internal.annotations.GuardedBy;
 import com.android.internal.annotations.VisibleForTesting;
 import com.android.modules.utils.build.SdkLevel;
 import com.android.net.module.util.BpfMap;
@@ -68,8 +69,12 @@
 
     private static final String CONFIGURATION_MAP_PATH =
             "/sys/fs/bpf/netd_shared/map_netd_configuration_map";
+    private static final String UID_OWNER_MAP_PATH =
+            "/sys/fs/bpf/netd_shared/map_netd_uid_owner_map";
     private static final U32 UID_RULES_CONFIGURATION_KEY = new U32(0);
     private static BpfMap<U32, U32> sConfigurationMap = null;
+    // BpfMap for UID_OWNER_MAP_PATH. This map is not accessed by others.
+    private static BpfMap<U32, UidOwnerValue> sUidOwnerMap = null;
 
     // LINT.IfChange(match_type)
     private static final long NO_MATCH = 0;
@@ -111,6 +116,14 @@
         sConfigurationMap = configurationMap;
     }
 
+    /**
+     * Set uidOwnerMap for test.
+     */
+    @VisibleForTesting
+    public static void setUidOwnerMapForTest(BpfMap<U32, UidOwnerValue> uidOwnerMap) {
+        sUidOwnerMap = uidOwnerMap;
+    }
+
     private static BpfMap<U32, U32> getConfigurationMap() {
         try {
             return new BpfMap<>(
@@ -120,10 +133,22 @@
         }
     }
 
+    private static BpfMap<U32, UidOwnerValue> getUidOwnerMap() {
+        try {
+            return new BpfMap<>(
+                    UID_OWNER_MAP_PATH, BpfMap.BPF_F_RDWR, U32.class, UidOwnerValue.class);
+        } catch (ErrnoException e) {
+            throw new IllegalStateException("Cannot open uid owner map", e);
+        }
+    }
+
     private static void setBpfMaps() {
         if (sConfigurationMap == null) {
             sConfigurationMap = getConfigurationMap();
         }
+        if (sUidOwnerMap == null) {
+            sUidOwnerMap = getUidOwnerMap();
+        }
     }
 
     /**
@@ -183,8 +208,10 @@
      *                                  cause of the failure.
      */
     public void addNaughtyApp(final int uid) {
-        final int err = native_addNaughtyApp(uid);
-        maybeThrow(err, "Unable to add naughty app");
+        synchronized (sUidOwnerMap) {
+            final int err = native_addNaughtyApp(uid);
+            maybeThrow(err, "Unable to add naughty app");
+        }
     }
 
     /**
@@ -195,8 +222,10 @@
      *                                  cause of the failure.
      */
     public void removeNaughtyApp(final int uid) {
-        final int err = native_removeNaughtyApp(uid);
-        maybeThrow(err, "Unable to remove naughty app");
+        synchronized (sUidOwnerMap) {
+            final int err = native_removeNaughtyApp(uid);
+            maybeThrow(err, "Unable to remove naughty app");
+        }
     }
 
     /**
@@ -207,8 +236,10 @@
      *                                  cause of the failure.
      */
     public void addNiceApp(final int uid) {
-        final int err = native_addNiceApp(uid);
-        maybeThrow(err, "Unable to add nice app");
+        synchronized (sUidOwnerMap) {
+            final int err = native_addNiceApp(uid);
+            maybeThrow(err, "Unable to add nice app");
+        }
     }
 
     /**
@@ -219,8 +250,10 @@
      *                                  cause of the failure.
      */
     public void removeNiceApp(final int uid) {
-        final int err = native_removeNiceApp(uid);
-        maybeThrow(err, "Unable to remove nice app");
+        synchronized (sUidOwnerMap) {
+            final int err = native_removeNiceApp(uid);
+            maybeThrow(err, "Unable to remove nice app");
+        }
     }
 
     /**
@@ -285,11 +318,13 @@
      */
     public int replaceUidChain(final String chainName, final boolean isAllowlist,
             final int[] uids) {
-        final int err = native_replaceUidChain(chainName, isAllowlist, uids);
-        if (err != 0) {
-            Log.e(TAG, "replaceUidChain failed: " + Os.strerror(-err));
+        synchronized (sUidOwnerMap) {
+            final int err = native_replaceUidChain(chainName, isAllowlist, uids);
+            if (err != 0) {
+                Log.e(TAG, "replaceUidChain failed: " + Os.strerror(-err));
+            }
+            return -err;
         }
-        return -err;
     }
 
     /**
@@ -302,8 +337,10 @@
      *                                  cause of the failure.
      */
     public void setUidRule(final int childChain, final int uid, final int firewallRule) {
-        final int err = native_setUidRule(childChain, uid, firewallRule);
-        maybeThrow(err, "Unable to set uid rule");
+        synchronized (sUidOwnerMap) {
+            final int err = native_setUidRule(childChain, uid, firewallRule);
+            maybeThrow(err, "Unable to set uid rule");
+        }
     }
 
     /**
@@ -328,8 +365,10 @@
             mNetd.firewallAddUidInterfaceRules(ifName, uids);
             return;
         }
-        final int err = native_addUidInterfaceRules(ifName, uids);
-        maybeThrow(err, "Unable to add uid interface rules");
+        synchronized (sUidOwnerMap) {
+            final int err = native_addUidInterfaceRules(ifName, uids);
+            maybeThrow(err, "Unable to add uid interface rules");
+        }
     }
 
     /**
@@ -348,8 +387,10 @@
             mNetd.firewallRemoveUidInterfaceRules(uids);
             return;
         }
-        final int err = native_removeUidInterfaceRules(uids);
-        maybeThrow(err, "Unable to remove uid interface rules");
+        synchronized (sUidOwnerMap) {
+            final int err = native_removeUidInterfaceRules(uids);
+            maybeThrow(err, "Unable to remove uid interface rules");
+        }
     }
 
     /**
@@ -361,8 +402,10 @@
      *                                  cause of the failure.
      */
     public void updateUidLockdownRule(final int uid, final boolean add) {
-        final int err = native_updateUidLockdownRule(uid, add);
-        maybeThrow(err, "Unable to update lockdown rule");
+        synchronized (sUidOwnerMap) {
+            final int err = native_updateUidLockdownRule(uid, add);
+            maybeThrow(err, "Unable to update lockdown rule");
+        }
     }
 
     /**
@@ -412,14 +455,23 @@
     }
 
     private static native void native_init();
+    @GuardedBy("sUidOwnerMap")
     private native int native_addNaughtyApp(int uid);
+    @GuardedBy("sUidOwnerMap")
     private native int native_removeNaughtyApp(int uid);
+    @GuardedBy("sUidOwnerMap")
     private native int native_addNiceApp(int uid);
+    @GuardedBy("sUidOwnerMap")
     private native int native_removeNiceApp(int uid);
+    @GuardedBy("sUidOwnerMap")
     private native int native_replaceUidChain(String name, boolean isAllowlist, int[] uids);
+    @GuardedBy("sUidOwnerMap")
     private native int native_setUidRule(int childChain, int uid, int firewallRule);
+    @GuardedBy("sUidOwnerMap")
     private native int native_addUidInterfaceRules(String ifName, int[] uids);
+    @GuardedBy("sUidOwnerMap")
     private native int native_removeUidInterfaceRules(int[] uids);
+    @GuardedBy("sUidOwnerMap")
     private native int native_updateUidLockdownRule(int uid, boolean add);
     private native int native_swapActiveStatsMap();
     private native void native_setPermissionForUids(int permissions, int[] uids);