Zygote: Fix dropping capabilities in containers

Casting a int to long will sign-extend it, so if capability bit 31
was set the bitmask would always have all the upper 32 bits set,
failing to drop any of the upper capabilities.

Instead of plain casting, use Integer.toUnsignedLong to always
zero-extend the bitmask

Change-Id: I9b4c9273e8eb09f7e231b5c579e7906d05b6e475

1 files changed, 2 insertions, 1 deletions

diff --git a/core/java/com/android/internal/os/ZygoteInit.java b/core/java/com/android/internal/os/ZygoteInit.java
index 076e4e118e66..2db9e0918d72 100644
--- a/core/java/com/android/internal/os/ZygoteInit.java
+++ b/core/java/com/android/internal/os/ZygoteInit.java
@@ -716,7 +716,8 @@ public class ZygoteInit {
         } catch (ErrnoException ex) {
             throw new RuntimeException("Failed to capget()", ex);
         }
-        capabilities &= ((long) data[0].effective) | (((long) data[1].effective) << 32);
+        capabilities &= Integer.toUnsignedLong(data[0].effective) |
+                (Integer.toUnsignedLong(data[1].effective) << 32);
 
         /* Hardcoded command line to start the system server */
         String[] args = {