Merge changes from topic "deny-create-user-dirs"

* changes:
  Zygote: relabel to either system_userdir_file or system_data_file
  BrightnessTracker: don't create stuff directly in /data/system_de

core/jni/com_android_internal_os_Zygote.cpp

@@ -1153,8 +1153,8 @@ static void relabelDir(const char* path, const char* context, fail_fn_t fail_fn)
   }
 }
 
-// Relabel all directories under a path non-recursively.
+// Relabel the subdirectories and symlinks in the given directory, non-recursively.
-static void relabelAllDirs(const char* path, const char* context, fail_fn_t fail_fn) {
+static void relabelSubdirs(const char* path, const char* context, fail_fn_t fail_fn) {
   DIR* dir = opendir(path);
   if (dir == nullptr) {
     fail_fn(CREATE_ERROR("Failed to opendir %s", path));
@@ -1231,11 +1231,19 @@ static void isolateAppData(JNIEnv* env, const std::vector<std::string>& merged_d
   snprintf(internalDePath, PATH_MAX, "/data/user_de");
   snprintf(externalPrivateMountPath, PATH_MAX, "/mnt/expand");
 
-  char* dataDataContext = nullptr;
+  // Get the "u:object_r:system_userdir_file:s0" security context.  This can be
-  if (getfilecon(internalDePath, &dataDataContext) < 0) {
+  // gotten from several different places; we use /data/user.
-    fail_fn(CREATE_ERROR("Unable to getfilecon on %s %s", internalDePath,
+  char* dataUserdirContext = nullptr;
+  if (getfilecon(internalCePath, &dataUserdirContext) < 0) {
+    fail_fn(CREATE_ERROR("Unable to getfilecon on %s %s", internalCePath,
         strerror(errno)));
   }
+  // Get the "u:object_r:system_data_file:s0" security context.  This can be
+  // gotten from several different places; we use /data/misc.
+  char* dataFileContext = nullptr;
+  if (getfilecon("/data/misc", &dataFileContext) < 0) {
+    fail_fn(CREATE_ERROR("Unable to getfilecon on /data/misc %s", strerror(errno)));
+  }
 
   MountAppDataTmpFs(internalLegacyCePath, fail_fn);
   MountAppDataTmpFs(internalCePath, fail_fn);
@@ -1330,19 +1338,19 @@ static void isolateAppData(JNIEnv* env, const std::vector<std::string>& merged_d
   // the file operations on tmpfs. If we set the label when we mount
   // tmpfs, SELinux will not happy as we are changing system_data_files.
   // Relabel dir under /data/user, including /data/user/0
-  relabelAllDirs(internalCePath, dataDataContext, fail_fn);
+  relabelSubdirs(internalCePath, dataFileContext, fail_fn);
 
   // Relabel /data/user
-  relabelDir(internalCePath, dataDataContext, fail_fn);
+  relabelDir(internalCePath, dataUserdirContext, fail_fn);
 
   // Relabel /data/data
-  relabelDir(internalLegacyCePath, dataDataContext, fail_fn);
+  relabelDir(internalLegacyCePath, dataFileContext, fail_fn);
 
-  // Relabel dir under /data/user_de
+  // Relabel subdirectories of /data/user_de
-  relabelAllDirs(internalDePath, dataDataContext, fail_fn);
+  relabelSubdirs(internalDePath, dataFileContext, fail_fn);
 
   // Relabel /data/user_de
-  relabelDir(internalDePath, dataDataContext, fail_fn);
+  relabelDir(internalDePath, dataUserdirContext, fail_fn);
 
   // Relabel CE and DE dirs under /mnt/expand
   dir = opendir(externalPrivateMountPath);
@@ -1355,14 +1363,15 @@ static void isolateAppData(JNIEnv* env, const std::vector<std::string>& merged_d
     auto cePath = StringPrintf("%s/user", volPath.c_str());
     auto dePath = StringPrintf("%s/user_de", volPath.c_str());
 
-    relabelAllDirs(cePath.c_str(), dataDataContext, fail_fn);
+    relabelSubdirs(cePath.c_str(), dataFileContext, fail_fn);
-    relabelDir(cePath.c_str(), dataDataContext, fail_fn);
+    relabelDir(cePath.c_str(), dataUserdirContext, fail_fn);
-    relabelAllDirs(dePath.c_str(), dataDataContext, fail_fn);
+    relabelSubdirs(dePath.c_str(), dataFileContext, fail_fn);
-    relabelDir(dePath.c_str(), dataDataContext, fail_fn);
+    relabelDir(dePath.c_str(), dataUserdirContext, fail_fn);
   }
   closedir(dir);
 
-  freecon(dataDataContext);
+  freecon(dataUserdirContext);
+  freecon(dataFileContext);
 }
 
 static void insertPackagesToMergedList(JNIEnv* env,

services/core/java/com/android/server/display/BrightnessTracker.java

@@ -505,12 +505,36 @@ public class BrightnessTracker {
         }
     }
 
+    // Return the path to the given file, either the new path
+    // /data/system/$filename, or the old path /data/system_de/$filename if the
+    // file exists there but not at the new path.  Only use this for EVENTS_FILE
+    // and AMBIENT_BRIGHTNESS_STATS_FILE.
+    //
+    // Explanation: this service previously incorrectly stored these two files
+    // directly in /data/system_de, instead of in /data/system where they should
+    // have been.  As system_server no longer has write access to
+    // /data/system_de itself, these files were moved to /data/system.  To
+    // lazily migrate the files, we simply read from the old path if it exists
+    // and the new one doesn't, and always write to the new path.  Note that
+    // system_server doesn't have permission to delete the old files.
+    private AtomicFile getFileWithLegacyFallback(String filename) {
+        AtomicFile file = mInjector.getFile(filename);
+        if (file != null && !file.exists()) {
+            AtomicFile legacyFile = mInjector.getLegacyFile(filename);
+            if (legacyFile != null && legacyFile.exists()) {
+                Slog.i(TAG, "Reading " + filename + " from old location");
+                return legacyFile;
+            }
+        }
+        return file;
+    }
+
     private void readEvents() {
         synchronized (mEventsLock) {
             // Read might prune events so mark as dirty.
             mEventsDirty = true;
             mEvents.clear();
-            final AtomicFile readFrom = mInjector.getFile(EVENTS_FILE);
+            final AtomicFile readFrom = getFileWithLegacyFallback(EVENTS_FILE);
             if (readFrom != null && readFrom.exists()) {
                 FileInputStream input = null;
                 try {
@@ -528,7 +552,7 @@ public class BrightnessTracker {
 
     private void readAmbientBrightnessStats() {
         mAmbientBrightnessStatsTracker = new AmbientBrightnessStatsTracker(mUserManager, null);
-        final AtomicFile readFrom = mInjector.getFile(AMBIENT_BRIGHTNESS_STATS_FILE);
+        final AtomicFile readFrom = getFileWithLegacyFallback(AMBIENT_BRIGHTNESS_STATS_FILE);
         if (readFrom != null && readFrom.exists()) {
             FileInputStream input = null;
             try {
@@ -1095,6 +1119,10 @@ public class BrightnessTracker {
         }
 
         public AtomicFile getFile(String filename) {
+            return new AtomicFile(new File(Environment.getDataSystemDirectory(), filename));
+        }
+
+        public AtomicFile getLegacyFile(String filename) {
             return new AtomicFile(new File(Environment.getDataSystemDeDirectory(), filename));
         }
 

services/tests/servicestests/src/com/android/server/display/BrightnessTrackerTest.java

@@ -1036,6 +1036,12 @@ public class BrightnessTrackerTest {
             return null;
         }
 
+        @Override
+        public AtomicFile getLegacyFile(String filename) {
+            // Don't have the test write / read from anywhere.
+            return null;
+        }
+
         @Override
         public long currentTimeMillis() {
             return mCurrentTimeMillis;