Improve the scan process

Use multi task to speed up the scan process

CRs-Fixed: 984513

base: fix native crash in system_server

Currently PackageManagerService uses multi-thread to scan
packages to speed up, when scan each package, it sometimes
will call SELinux's restorecon, then libselinux uses global
variable fc_sehandle to selabel_lookup and write in compile_regex,
so it's not thread-safe, so will cause invalid address with
possibility. From backtrace, the final crash happens in pcre_exec.

Add one lock in NativeLibraryHelper to make restorecon safe.

Change-Id: Ida43fcda01d3450befea6afa0be5da27bb195def
CRs-Fixed: 1002406, 1027381

1 files changed, 8 insertions, 2 deletions

diff --git a/core/java/com/android/internal/content/NativeLibraryHelper.java b/core/java/com/android/internal/content/NativeLibraryHelper.java
index f479f4f..f5b948f 100644
--- a/core/java/com/android/internal/content/NativeLibraryHelper.java
+++ b/core/java/com/android/internal/content/NativeLibraryHelper.java
@@ -62,6 +62,8 @@ public class NativeLibraryHelper {
     // that the cpuAbiOverride must be clear.
     public static final String CLEAR_ABI_OVERRIDE = "-";
 
+    private static final Object mRestoreconSync = new Object();
+
     /**
      * A handle to an opened package, consisting of one or more APKs. Used as
      * input to the various NativeLibraryHelper methods. Allows us to scan and
@@ -275,8 +277,12 @@ public class NativeLibraryHelper {
                 throw new IOException("Cannot chmod native library directory "
                         + path.getPath(), e);
             }
-        } else if (!SELinux.restorecon(path)) {
-            throw new IOException("Cannot set SELinux context for " + path.getPath());
+        } else {
+            synchronized (mRestoreconSync) {
+                if (!SELinux.restorecon(path)) {
+                    throw new IOException("Cannot set SELinux context for " + path.getPath());
+                }
+            }
         }
     }