posix_getppid
My original code is an example of stupid code leading to a security vulnerability. The username and password can be viewed using the *NIX command `ps'.
Here is a better approach:
<?php
$desc = array(
0 => array("pipe","r"),
1 => array("pipe","w"),
2 => array("file","/tmp/error.out","a")
);
$proc = proc_open('/opt/webpanel/bin/pam_auth -o -1',$desc, $pipes);
if (is_resource($proc)) {
fwrite($pipes[0],$_POST['usr']);
fwrite($pipes[0]," ");
fwrite($pipes[0],$_POST['pass']);
fwrite($pipes[0],"\n");
fclose($pipes[0]);
echo stream_get_contents($pipes[1]);
fclose($pipes[1]);
}
$retval = proc_close($proc);
?>
Example code is mostly a verbatim copy from the proc_open() page.
http://php.net/manual/en/function.proc-open.php
posix_getpwnam
(PHP 4, PHP 5)
posix_getpwnam — Devuelve información sobre un usuario a traves del nombre de usuario
Description
array posix_getpwnam
( string $username
)
Devuelve un vector asociativo conteniendo información sobre un usuario referenciado por un nombre alfanumérico, pasado a la función en el parametro username .
Los elementos del vector devuelto son:
| Elemento | Descripción |
|---|---|
| name | El elemento name contiene el nombre de usuario del usuario. Este es un nombre, normalmente menor de 16 caracteres, que no es su nombre completo, pero identifica al usario. Este debe ser el mismo que el parámetro username usado en la llamada a la función y por lo tanto es redundante. |
| passwd | El elemento passwd contiene la contraseña del usuario en un formato encriptado. Normalmente, por ejemplo en un sistema que este utilizando contraseñas "shadow", devolverá un asterisco. |
| uid | El ID de usuario del usuario en formato numérico. |
| gid | El ID de grupo del usuario. Utiliza la función posix_getgrgid() para resolver el nombre del grupo y una lista de sus miembros. |
| gecos | GECOS es un término obsoleto que se refiere al campo apuntado de información en un sistema de procesamiento batch Honeywell. El campo y sus contenidos han sido formalizado por POSIX y contiene una lista separada por comas con el nombre completo del usuario, teléfono del trabajo, número de oficina y télefono de casa. En muchos sistemas solo está disponible el nombre completo del usuario. |
| dir | Este elemento contiene la ruta absoluta al directorio del usuario (directorio home). |
| shell | El elemento shell contiene la ruta absoluta al ejecutable del shell por defecto del usuario. |
add a note
User Contributed Notesposix_getpwnam
Didar Hossain
19-Sep-2007 10:05
19-Sep-2007 10:05
Didar Hossain
06-Aug-2006 01:50
06-Aug-2006 01:50
Okay, this is a DIRTY HACK that I came up with
I am not a regular coder, so please weigh the relevant security considerations
<?php
$cmdstr = 'echo ' . $_POST['user'] . ' ' . $_POST['pass'];
$cmdstr .= ' | /home/didar/pam_auth -n common-auth ';
exec($cmdstr,$read);
if (strstr($read[0],"OK")) {
echo "Success";
} else {
echo "Failed";
}
?>
The code above makes use of the "pam_auth" or "squid_pam_auth" helper program from Squid package. Go to the following link for more information about it -
http://devel.squid-cache.org/hno/pam_auth-2.0.txt
WARNING: This is simply a hack. Always USE SSL/TLS in the orignating submit form. Also, always do sanity checks on the user input data.
bau at kg-fds dot de
18-Feb-2006 05:29
18-Feb-2006 05:29
Oh I forgot the following:
to change a Users password via PHP,
you can use the following (under Linux with installed Samba):
exec('echo -e "'.$oldpassword.'\n'.$newpassword.'\n'.$newpassword.'
"|smbpasswd -U'.$user.' -s')
The exec-command returns ""
if an error occured (then see the error_log of the web-server)
or a message "The password has been changed".
Good luck.
Baumgärtner
bau at kg-fds dot de
18-Feb-2006 05:22
18-Feb-2006 05:22
Hello, I've tried another, more easier way to check passwords than checking it to a pop3-server. If you are running a samba-server or a Windows PDC, so you can try to connect with the username/password you want to check to the netlogon of this server:
if (exec('echo "exit"|smbclient //server/netlogon -U'.$user.' '.$pass)=="") { ... }
If the username/password doesn't match, then the exec-command under LINUX returns an error.
Good luck
Baumgärtner
bau at kg-fds dot de
14-Feb-2006 07:24
14-Feb-2006 07:24
If you are running a pop3-daemon, so you can do authentification on pop3 by using fsockopen :-) and checking whether it returns +OK or -ERR
corychristison at lavacube dot net
17-Oct-2004 11:33
17-Oct-2004 11:33
For those of you who are writing daemons with PHP and are one for security. This function will not return any info if you have called PHP's chroot() function.
Took me a few minutes why it wouldn't find the user it was searching for.
marcus at nospamsynchromedia dot co dot uk
23-Aug-2002 08:12
23-Aug-2002 08:12
Given a non-existent username, this function returns a boolean FALSE.
perreal at lyon dot cemagref dot fr
18-Apr-2002 03:47
18-Apr-2002 03:47
To check passwords on a Unix-box, look at the mod_auth_external module for Apache, it uses external programs to do the real job. The server won't ever read the encrypted password.
One of them, pwauth, can be configured to use PAM or whatever is used on your system. Users that can run this program are configured at compile time. And this program can be called from PHP with exec(...).
vision_1967 at hotmail dot com
20-Nov-2001 07:23
20-Nov-2001 07:23
I needed to get access to the user information to do login/validation via an SSL connection and encountered the same problem with receiving '*' in the password field. After checking the documentation on posix_getpwnam, I saw a previous solution involving coding a C program. This was a bit bulky for me so I came up with my own solution.
Variations on this theme can probably be done to make the solution more programmer/reader friendly, but the way I did it accomplished the task that I needed to do.
IF the information you need to get from posix_getpwnam comes from a host participating in an NIS network, you can accomplish the same thing with the following command:
$autharray = split(":",`ypmatch $USER passwd`);
(pretty long explanation for such a short solution huh?)
You'll have to get at the fields by their index number ($autharray[0], $autharray[1], ...) using this method.
To create an associative array that is plug-in compatible with the posix_getpwnam function, you'll probably need to use the 'list' specifier to do the assignments.
I hope this helps someone.
--S
darryl at pointclark dot net
18-Oct-2001 05:43
18-Oct-2001 05:43
If you need to validate a *real* unix password on a system using shadowed passwords, the posix_getpwnam() function in PHP won't work (as mentioned, 'x', or '*', will be in the password field).
I have a need to verify a user/pass within PHP (using SSL!). I don't know if this is the best way, but it's what I'm doing at the moment (works well!).
First, you need some help from the OS. I wrote a tiny C utility that does the shadow look-up for me... It requires root access to read /etc/shadow. So after you compile (gcc -O2 -s -o spasswd -lcrypt spasswd.c), you need to either use sudo to run it, or
# chown root spasswd && chmod u+s spasswd
To code that I'm using to authenticate a user/pass from PHP looks like:
function Authenticate($realm)
{
global $PHP_AUTH_USER;
global $PHP_AUTH_PW;
if(!isset($PHP_AUTH_USER))
{
header("WWW-Authenticate: Basic realm=\"$realm\"");
header("HTTP/1.0 401 Unauthorized");
return false;
}
else
{
if(($fh = popen("/usr/sbin/spasswd", "w")))
{
fputs($fh, "$PHP_AUTH_USER $PHP_AUTH_PW");
$r = pclose($fh);
if(!$r)
return true;
}
}
header("WWW-Authenticate: Basic realm=\"$realm\"");
header("HTTP/1.0 401 Unauthorized");
return false;
}
The C source for spasswd.c:
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <crypt.h>
#include <shadow.h>
static char salt[12], user[128], pass[128];
void die(void)
{
memset(salt, '\0', 12);
memset(user, '\0', 128);
memset(pass, '\0', 128);
}
int main(int argc, char *argv[])
{
struct spwd *passwd;
atexit(die); die();
if(fscanf(stdin, "%127s %127s", user, pass) != 2)
return 1;
if(!(passwd = getspnam(user)))
return 1;
strncpy(salt, passwd->sp_pwdp, 11);
strncpy(pass, crypt(pass, salt), 127);
if(!strncmp(pass, passwd->sp_pwdp, 127))
return 0;
return 1;
}
Hope this helps someone...
sezery at damla dot net
03-Oct-2001 09:09
03-Oct-2001 09:09
User and group functions do not work on recent Redhat systems since these functions are based on /etc/group file but new redhat does not put group members' list into this file. Instead you need to examine /etc/passwd file and find members of a group by checking group id.