--- src/sexec.c.orig	2016-06-01 15:12:38.000000000 +0100
+++ src/sexec.c	2016-06-08 20:12:26.305999334 +0100
@@ -99,10 +99,12 @@
     int lockfile_fd;
     int retval = 0;
     int bind_mount_writable = 0;
-    uid_t uid = getuid();
-    gid_t gid = getgid();
+    int gid_list_count;
+    uid_t uid;
+    gid_t gid;
+    gid_t *gid_list;
     pid_t namespace_fork_pid = 0;
-    struct passwd *pw = getpwuid(uid);
+    struct passwd *pw;
 
 
 //****************************************************************************//
@@ -115,6 +117,17 @@
 
     openlog("Singularity", LOG_CONS | LOG_NDELAY, LOG_LOCAL0);
 
+    // Get all user/group info
+    uid = getuid();
+    gid = getgid();
+    gid_list_count = getgroups(0, NULL);
+    gid_list = (gid_t *) malloc(sizeof(gid_t) * gid_list_count);
+    if ( getgroups(gid_list_count, gid_list) < 0 ) {
+        fprintf(stderr, "ABORT: Could not obtain current supplementary group list: %s\n", strerror(errno));
+        return(255);
+    }
+    pw = getpwuid(uid);
+
     // Check to make sure we are installed correctly
     if ( seteuid(0) < 0 ) {
         fprintf(stderr, "ABORT: Check installation, must be performed by root.\n");
@@ -617,6 +630,10 @@
                 fprintf(stderr, "ABORT: failed enter CONTAINERIMAGE: %s\n", containerpath);
                 return(255);
             }
+                if ( chdir("/") < 0 ) {
+                    fprintf(stderr, "ABORT: Could not chdir after chroot to /: %s\n", strerror(errno));
+                    return(1);
+                }
 
 
 //****************************************************************************//
@@ -641,6 +658,10 @@
 // Drop all privledges for good
 //****************************************************************************//
 
+            if ( setgroups(gid_list_count, gid_list) < 0 ) {
+                fprintf(stderr, "ABORT: Could not reset supplementary group list: %s\n", strerror(errno));
+                return(255);
+            }
             if ( setregid(gid, gid) < 0 ) {
                 fprintf(stderr, "ABORT: Could not dump real and effective group privledges!\n");
                 return(255);
@@ -661,7 +682,6 @@
                 return(1);
             }
 
-//TODO: Fix logic so that we use cwd_fd for OS dirs
             if ( is_dir(cwd) == 0 ) {
                if ( chdir(cwd) < 0 ) {
                     fprintf(stderr, "ABORT: Could not chdir to: %s\n", cwd);