Password Authentication Application

rajsun · 03-02-2005, 03:54 AM

hi all,
I'm Rajesh new to this mailing list. I'm trying out to write an application to authenticate "User name" & "Password" in Suse Linux, what we get in login console. Is there any system calls or APIs in Suse Linux to verify the user and allow him/her to log in...??
Please help me out .....

hk_linux · 03-03-2005, 12:22 AM

hi rajesh,
For authenticating the linux username, you need to encrypt the password and check with the entry in the /etc/shadow. So u will need root privileges for ur application.
getspnam(username) is a call which will return a structure spwd, which will contain the info related to the user. Then u need to encrypt the password the user has entered and compare it with the one in the structure.
I have done this some time back in RedHat, but i believe shd work for Suse also.

HTH

hk_linux · 03-04-2005, 12:15 AM

hi,
I couldnt find the source code in C. I tried rewriting. Encountered some prob. Didnt have time to debug.

See if this perl snippet will be of use for u. This was given by my friend.
< code>
#!/usr/bin/perl -w
$user = $ARGV[0];
$pass = $ARGV[1];

open(PASS,"/etc/shadow") or die "cant open file";
while($Lines=<PASS>)
{
@me=split(/:/,$Lines);
if ($me[0] eq $user)
{
if (crypt ($pass,$me[1]) eq $me[1])
{
print "Password is correct\n";
last;
}
else
{
print "Password is incorrect\n";
last;
}
}
}
close(PASS);

< /code>