Procedure Model

Type:    (  )Web Page              (  )CGI Script              (X)Shared Library      (  )System API

Name: lib/pw_check

Assigned to:

Reference:

Description

This function takes a string parameter and runs it against the system pw_check utility to see if it is a sufficiently strong password. If not, the function returns a string describing the weakness(es) of the password.

Implementation Skills

C

Parameter List

password- a string containing the password string to test

Called By:

user/validate.cgi

Can Call:

crack.h

Function Description

#include <stdio.h>
#include <stdlib.h>
#include <crack.h>

int main(int argc, char *argv[]) {
   int i;
   char* pw_check;
   char* password;
   char* dict_path = “/usr/lib/cracklib_dict”;
   char* null_string = “”;
   char* bad_usage =
         "Usage: pw_check [password]";

   if (argc != 2) {
      fputs(bad_usage,stdout);
      return (-1);
   }

   password  = argv[1];
   pw_check = FascistCheck(password, dict_path);

   if (pw_check != NULL)
      fputs(pw_check,stdout);
   else fputs(null_string,stdout);

   exit(0);
}

Usage within a PERL or Shell Script:

$output=`pw_check([password])`;

if ($output eq “”) {
   # password is good
}
else {
   # password is bad. Reason is stored in $output
}

Possible Exit Conditions and Return Values

1. The program returns a –1 if an insufficient number of parameters were passed to the command. The description of the proper way to call the program should be passed through to the calling routine using the stdout handle. Check the contents of the $output variable in the above function description example.
2. The program returns a 0 if the program is properly called. If the password is sufficiently strong, then an empty string is passed back through the stdout handle. Otherwise, a text string describing the problems with the password are listed. Since multiple problems can exist, these lines will be separated with a newline character (“\n”).

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