Hello monks,

I must change passwords from customers with a cgi-script (html -> cgi-script -> change pw in /etc/passwd). I've create a short script but I'm not sure, if it's safty or not?

How it works: a user must enter his username, old password and his new password. First, I check if the old password matches his actual password. If so, I create with some commandline tools the password string for /etc/shadow. 

#!/usr/bin/perl -w

my $benutzername = "test";
my $passwordold = "password";
my $passwordnew = "freeSt19"; 


$pwd = (getpwnam($benutzername))[1];

#check, if the user knows his old password: 
if (crypt($passwordold, $pwd) ne $pwd) {
    die "Sorry...\n";
} else {
    print "ok\n";
}


my $cryptedShadowString = `echo "$passwordnew"|openssl passwd -1 -stdi
+n`;
chomp($cryptedShadowString);


my @Zeilen = ("");
open(DATA, "</etc/shadow") || die "Datei mit E-Mails nicht gefunden\n"
+;
while(<DATA>)
 {
  push(@Zeilen,$_);
 }
close(DATA);


#Write the new shadow-file
open(SHADOW, ">/etc/shadow");
for(@Zeilen){
    if( $_ =~ m/^$benutzername/){
        my @pwField = split( /:/, $_);
        $pwField[1] = $cryptedShadowString;
        print SHADOW $pwField[0].":".$pwField[1].":".$pwField[2].":".$
+pwField[3].":".$pwField[4].":".$pwField[5].":".$pwField[6].":".$pwFie
+ld[7].":".$pwField[8];
        
    }else{
        print SHADOW $_;
    }    

}
close(SHADOW);

$mode = 0640;
chmod $mode, "/etc/shadow";
`chown root /etc/shadow`;
`chgrp shadow /etc/shadow`;

[download]
I will also implement a feature which disallows password changes for root and other system accouts. Would be nice to get some feedback!

In reply to change unix password with cgi-script by miggel15

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