From 6dbd9ee40a5c13e8e4a5b1aca039bb6c00031501 Mon Sep 17 00:00:00 2001
From: Jing Ji <jji@google.com>
Date: Thu, 4 Aug 2022 11:36:26 -0700
Subject: [PATCH] DO NOT MERGE: Context#startInstrumentation could be started
 from SHELL only now.

Or, if an instrumentation starts another instrumentation and so on,
and the original instrumentation is started from SHELL, allow all
Context#startInstrumentation calls in this chain.

Otherwise, it'll throw a SecurityException.

Bug: 237766679
Test: atest CtsAppTestCases:InstrumentationTest
Merged-In: Ia08f225c21a3933067d066a578ea4af9c23e7d4c
Merged-In: I1b76f61c5fd6c9f7e738978592260945a606f40c
Merged-In: I3ea7aa27bd776fec546908a37f667f680da9c892
Change-Id: I7ca7345b064e8e74f7037b8fa3ed45bb6423e406
(cherry picked from commit 8c90891a38ecb5047e115e13baf700a8b486a5d1)
Merged-In: I7ca7345b064e8e74f7037b8fa3ed45bb6423e406
---
 .../server/am/ActivityManagerService.java     | 41 ++++++++++++++++++-
 1 file changed, 39 insertions(+), 2 deletions(-)

diff --git a/services/core/java/com/android/server/am/ActivityManagerService.java b/services/core/java/com/android/server/am/ActivityManagerService.java
index 4e48f422a2fe3..73ecd14090c99 100644
--- a/services/core/java/com/android/server/am/ActivityManagerService.java
+++ b/services/core/java/com/android/server/am/ActivityManagerService.java
@@ -4306,6 +4306,29 @@ public int getPackageProcessState(String packageName, String callingPackage) {
         return procState;
     }
 
+    @GuardedBy("this")
+    private boolean hasActiveInstrumentationLocked(int pid) {
+        if (pid == 0) {
+            return false;
+        }
+        synchronized (mPidsSelfLocked) {
+            ProcessRecord process = mPidsSelfLocked.get(pid);
+            return process != null && process.instrumentationClass != null;
+        }
+    }
+
+    private String getPackageNameByPid(int pid) {
+        synchronized (mPidsSelfLocked) {
+            final ProcessRecord app = mPidsSelfLocked.get(pid);
+
+            if (app != null && app.info != null) {
+                return app.info.packageName;
+            }
+
+            return null;
+        }
+    }
+
     private boolean isCallerShell() {
         final int callingUid = Binder.getCallingUid();
         return callingUid == Process.SHELL_UID || callingUid == Process.ROOT_UID;
@@ -18947,7 +18970,9 @@ public boolean startInstrumentation(ComponentName className,
             IInstrumentationWatcher watcher, IUiAutomationConnection uiAutomationConnection,
             int userId, String abiOverride) {
         enforceNotIsolatedCaller("startInstrumentation");
-        userId = mUserController.handleIncomingUser(Binder.getCallingPid(), Binder.getCallingUid(),
+        final int callingUid = Binder.getCallingUid();
+        final int callingPid = Binder.getCallingPid();
+        userId = mUserController.handleIncomingUser(callingPid, callingUid,
                 userId, false, ALLOW_FULL_ONLY, "startInstrumentation", null);
         // Refuse possible leaked file descriptors
         if (arguments != null && arguments.hasFileDescriptors()) {
@@ -18987,7 +19012,7 @@ public boolean startInstrumentation(ComponentName className,
                 String msg = "Permission Denial: starting instrumentation "
                         + className + " from pid="
                         + Binder.getCallingPid()
-                        + ", uid=" + Binder.getCallingPid()
+                        + ", uid=" + Binder.getCallingUid()
                         + " not allowed because package " + ii.packageName
                         + " does not have a signature matching the target "
                         + ii.targetPackage;
@@ -18995,6 +19020,18 @@ public boolean startInstrumentation(ComponentName className,
                 throw new SecurityException(msg);
             }
 
+            if (!Build.IS_DEBUGGABLE && callingUid != Process.ROOT_UID && callingUid != Process.SHELL_UID
+                    && callingUid != Process.SYSTEM_UID && !hasActiveInstrumentationLocked(callingPid)) {
+                // If it's not debug build and not called from root/shell/system uid, reject it.
+                final String msg = "Permission Denial: instrumentation test "
+                        + className + " from pid=" + callingPid + ", uid=" + callingUid
+                        + ", pkgName=" + getPackageNameByPid(callingPid)
+                        + " not allowed because it's not started from SHELL";
+                Slog.wtfQuiet(TAG, msg);
+                reportStartInstrumentationFailureLocked(watcher, className, msg);
+                throw new SecurityException(msg);
+            }
+
             final long origId = Binder.clearCallingIdentity();
             // Instrumentation can kill and relaunch even persistent processes
             forceStopPackageLocked(ii.targetPackage, -1, true, false, true, true, false, userId,