Tainted variable problem (PERL)
 

Hi all,

some unusual problem. I have written a script without any -T but still it is doing taint checking...

I am passing directory name like /abc/foo/ as command line param, then it is accessed in the script using ARGV[1];

e.g. my $a = $ARGV[1];

when I use $a, it gives Insecure dependency in `` while running with -T switch.

Why ??? I am not using -T either.

Any help will be appreciated.

Code snippet is below:


my $ROOT_FS = $ARGV[1];

# setting some initial environment settings

# first changing to root

my $ruid = $<;
$<=$>;
# executing priveleged commands
system ("chown", "-R", "root:root", $ROOT_FS);
system ("chmod", "-R", "777", $ROOT_FS);
my $logfile = $ROOT_FS."temp/root_fs2/mnt/tmp/resultlog";
system (">$logfile");
# restoring ruid
$<=$ruid;


it gives error messages from all system commands. It is executed y user apache and the script needs root privilege to run the commands.


rajat garg

Is your script suid (or sgid)? perl understands -T whenever you run your script suid. If you are quite sure that what is in $ROOT_FS is safe, you can do this:
to untaint it. But make sure it's safe!