From 3555fa2f09972cb238eeeee6b0d7ed286d731989 Mon Sep 17 00:00:00 2001
From: Christopher Tate <ctate@google.com>
Date: Mon, 7 Jun 2021 15:02:45 -0700
Subject: [PATCH] Fix side effects of trace-ipc and dumpheap commands

These shell commands were implicitly deleting any client-named file for
which the system uid had deletion capability.  They no longer do this,
instead using only the client's own capabilities and file manipulation
modes.

Bug: 185398942
Test: manual "adb shell cmd activity dumpheap system_server /data/system/last-fstrim"
Test: atest CtsPermissionTestCases:ShellCommandPermissionTest
Merged-In: Ie61ab2c3f4bfbd04de09ca99c1116d1129461e8f
Change-Id: Ie61ab2c3f4bfbd04de09ca99c1116d1129461e8f
---
 .../server/am/ActivityManagerShellCommand.java       | 12 +++++-------
 1 file changed, 5 insertions(+), 7 deletions(-)

diff --git a/services/core/java/com/android/server/am/ActivityManagerShellCommand.java b/services/core/java/com/android/server/am/ActivityManagerShellCommand.java
index 8f16ed4768dee..a19e475a46a1b 100644
--- a/services/core/java/com/android/server/am/ActivityManagerShellCommand.java
+++ b/services/core/java/com/android/server/am/ActivityManagerShellCommand.java
@@ -90,7 +90,6 @@ import com.android.internal.util.MemInfoReader;
 import com.android.internal.util.Preconditions;
 
 import java.io.BufferedReader;
-import java.io.File;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.InputStreamReader;
@@ -759,8 +758,7 @@ final class ActivityManagerShellCommand extends ShellCommand {
             return -1;
         }
 
-        File file = new File(filename);
-        file.delete();
+        // Writes an error message to stderr on failure
         ParcelFileDescriptor fd = openFileForSystem(filename, "w");
         if (fd == null) {
             return -1;
@@ -914,16 +912,16 @@ final class ActivityManagerShellCommand extends ShellCommand {
             t.set(System.currentTimeMillis());
             heapFile = "/data/local/tmp/heapdump-" + t.format("%Y%m%d-%H%M%S") + ".prof";
         }
-        pw.println("File: " + heapFile);
-        pw.flush();
 
-        File file = new File(heapFile);
-        file.delete();
+        // Writes an error message to stderr on failure
         ParcelFileDescriptor fd = openFileForSystem(heapFile, "w");
         if (fd == null) {
             return -1;
         }
 
+        pw.println("File: " + heapFile);
+        pw.flush();
+
         final CountDownLatch latch = new CountDownLatch(1);
 
         final RemoteCallback finishCallback = new RemoteCallback(new OnResultListener() {