Answers: shell script - Unable to run shel scrip file, permission denied

gpuguy

I am having shell script file, basically a setup file for installing xilinx tools. The name of the file is xsetup

enter image description here

Also i checked its permission after doing this

chmod  777 xsetup

enter image description here

In fact the entire folder's (in which my xsetup is there )permission is like this: (file access I made read and write for every one, not shown in this screenshot ) enter image description here

However, I am getting errors when I am trying to execute the file:

[root@sulaptop xilinx]# sh xsetup
xsetup: line 30: ./bin/lin/xsetup: Permission denied
[root@sulaptop xilinx]# bash xsetup 
xsetup: line 30: ./bin/lin/xsetup: Permission denied
[root@sulaptop xilinx]#

Why I am getting this permission error when I am already logged in as root ?. here are the content of this script:

#! /bin/sh
export PATH || exec /bin/sh "$0" $argv
# Get the path to this exec
setuploc=`dirname "$0"`

unset LANG
platform=`uname -s`

# run setup executable depending on different platform
if [ "$platform" = "Linux" ]
then
    machineType=`uname -m`; # Get the machine type
    if [ "$machineType" = "x86_64" ]
    then
    # 64 bit
        if [ -f "$setuploc/bin/lin64/xsetup" ]
        then
            "$setuploc/bin/lin64/xsetup" $*
        else
            if [ -f "$setuploc/bin/lin/xsetup" ]
            then
                "$setuploc/bin/lin/xsetup" $*
            else
                echo "Product is not supported on \"$platform\" platform."
            fi            
        fi
    else
        if [ -f "$setuploc/bin/lin/xsetup" ]
        then
            "$setuploc/bin/lin/xsetup" $*
        else
            echo "Product is not supported on \"$platform $machineType\" platform."
        fi
    fi
else
    echo "Un-supported platform: $platform"
fi

Line no 30 is first

"$setuploc/bin/lin/xsetup" $*

from the bottom

Platform

Fedora 17 , 64 bit as i got one flags with lm

grep lm /proc/cpuinfo:

 lahf_lm ida arat epb xsaveopt pln pts dtherm tpr_shadow vnmi flexpriority ept vpid fsgsbase smep erms
flags       : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe nx rdtscp lm constant_tsc arch_perfmon pebs bts xtopology nonstop_tsc aperfmperf eagerfpu pni pclmulqdq dtes64 monitor ds_cpl vmx est tm2 ssse3 cx16 xtpr pdcm pcid sse4_1 sse4_2 x2apic popcnt tsc_deadline_timer aes xsave avx f16c rdrand lahf_lm

JdeBP

You've changed the permissions for /home/msz/xilinx/xsetup. The nested script being invoked by your script is /home/msz/xilinx/bin/lin/xsetup, however. Fix the permissions on the right file.

shell script - Strange strace and setuid behaviour: permission denied under strace, but not running normally

shell-script strace setuid

James

This is related to this question.

I have a script (fix-permissions.sh) that fixes some file permissions:

#! /bin/bash 
sudo chown -R person:group /path/
sudo chmod -R g+rw /path/

And a small c program to run this, which is setuided:

#include "sys/types.h"
#include "unistd.h"
int main(){
    setuid(geteuid());
    return system("/path/fix-permissions.sh");
}

Directory:

-rwsr-xr-x  1 root  root  7228 Feb 19 17:33 fix-permissions
-rwx--x--x  1 root  root   112 Feb 19 13:38 fix-permissions.sh

If I do this, everything seems fine, and the permissions do get correctly fixed:

       james $ sudo su someone-else
someone-else $ ./fix-permissions

but if I use strace, I get:

someone-else $ strace ./fix-permissions
/bin/bash: /path/fix-permissions.sh: Permission denied

It's interesting to note that I get the same permission denied error with an identical setup (permissions, c program), but a different script, even when not using strace. Is this some kind of heureustic magic behaviour in setuid that I'm uncovering?

How should I figure out what's going on?

System is Ubuntu 10.04.2 LTS, Linux 2.6.32.26-kvm-i386-20101122 #1 SMP

Home

shell script - Unable to run shel scrip file, permission denied