From 8b3e6b0df102901f938cd0687f9994a3ff767fcf Mon Sep 17 00:00:00 2001
From: Todd Kennedy <toddke@google.com>
Date: Wed, 12 Aug 2015 08:26:15 -0700
Subject: Promote system app permissions

When upgrading from a pre-M version of Android, install permissions for
exisiting system are promoted to runtime permissions. This only happens
for apps that existed prior to the OTA. Other system apps targeting M
are not automatically granted any permissions.

Bug: 22970710
Change-Id: I964ee3f93c66ea43fbb1be6b5ac6b09ddea3c385
---
 .../android/server/pm/PackageManagerService.java   | 42 +++++++++++++++++++---
 1 file changed, 38 insertions(+), 4 deletions(-)

diff --git a/services/core/java/com/android/server/pm/PackageManagerService.java b/services/core/java/com/android/server/pm/PackageManagerService.java
index 6a4ae3d..21e256e 100644
--- a/services/core/java/com/android/server/pm/PackageManagerService.java
+++ b/services/core/java/com/android/server/pm/PackageManagerService.java
@@ -481,12 +481,21 @@ public class PackageManagerService extends IPackageManager.Stub {
         new ArrayMap<String, ArrayMap<String, PackageParser.Package>>();
 
     /**
-     * Tracks new system packages [receiving in an OTA] that we expect to
+     * Tracks new system packages [received in an OTA] that we expect to
      * find updated user-installed versions. Keys are package name, values
      * are package location.
      */
     final private ArrayMap<String, File> mExpectingBetter = new ArrayMap<>();
 
+    /**
+     * Tracks existing system packages prior to receiving an OTA. Keys are package name.
+     */
+    final private ArraySet<String> mExistingSystemPackages = new ArraySet<>();
+    /**
+     * Whether or not system app permissions should be promoted from install to runtime.
+     */
+    boolean mPromoteSystemApps;
+
     final Settings mSettings;
     boolean mRestoredSettings;
 
@@ -2028,6 +2037,24 @@ public class PackageManagerService extends IPackageManager.Stub {
                 }
             }
 
+            final VersionInfo ver = mSettings.getInternalVersion();
+            mIsUpgrade = !Build.FINGERPRINT.equals(ver.fingerprint);
+            // when upgrading from pre-M, promote system app permissions from install to runtime
+            mPromoteSystemApps =
+                    mIsUpgrade && ver.sdkVersion <= Build.VERSION_CODES.LOLLIPOP_MR1;
+
+            // save off the names of pre-existing system packages prior to scanning; we don't
+            // want to automatically grant runtime permissions for new system apps
+            if (mPromoteSystemApps) {
+                Iterator<PackageSetting> pkgSettingIter = mSettings.mPackages.values().iterator();
+                while (pkgSettingIter.hasNext()) {
+                    PackageSetting ps = pkgSettingIter.next();
+                    if (isSystemApp(ps)) {
+                        mExistingSystemPackages.add(ps.name);
+                    }
+                }
+            }
+
             // Collect vendor overlay packages.
             // (Do this before scanning any apps.)
             // For security and version matching reason, only consider
@@ -2247,8 +2274,6 @@ public class PackageManagerService extends IPackageManager.Stub {
             // cases get permissions that the user didn't initially explicitly
             // allow...  it would be nice to have some better way to handle
             // this situation.
-            final VersionInfo ver = mSettings.getInternalVersion();
-
             int updateFlags = UPDATE_PERMISSIONS_ALL;
             if (ver.sdkVersion != mSdkVersion) {
                 Slog.i(TAG, "Platform changed from " + ver.sdkVersion + " to "
@@ -2257,6 +2282,9 @@ public class PackageManagerService extends IPackageManager.Stub {
             }
             updatePermissionsLPw(null, null, updateFlags);
             ver.sdkVersion = mSdkVersion;
+            // clear only after permissions have been updated
+            mExistingSystemPackages.clear();
+            mPromoteSystemApps = false;
 
             // If this is the first boot, and it is a normal boot, then
             // we need to initialize the default preferred apps.
@@ -2268,7 +2296,6 @@ public class PackageManagerService extends IPackageManager.Stub {
 
             // If this is first boot after an OTA, and a normal boot, then
             // we need to clear code cache directories.
-            mIsUpgrade = !Build.FINGERPRINT.equals(ver.fingerprint);
             if (mIsUpgrade && !onlyCore) {
                 Slog.i(TAG, "Build fingerprint changed; clearing code caches");
                 for (int i = 0; i < mSettings.mPackages.size(); i++) {
@@ -8356,6 +8383,13 @@ public class PackageManagerService extends IPackageManager.Stub {
                     } else if (origPermissions.hasInstallPermission(bp.name)) {
                         // For legacy apps that became modern, install becomes runtime.
                         grant = GRANT_UPGRADE;
+                    } else if (mPromoteSystemApps
+                            && isSystemApp(ps)
+                            && mExistingSystemPackages.contains(ps.name)) {
+                        // For legacy system apps, install becomes runtime.
+                        // We cannot check hasInstallPermission() for system apps since those
+                        // permissions were granted implicitly and not persisted pre-M.
+                        grant = GRANT_UPGRADE;
                     } else {
                         // For modern apps keep runtime permissions unchanged.
                         grant = GRANT_RUNTIME;
-- 
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