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/** Fichier auth.c
**
** Routines de gestion des mots de passe
**
** Copyright (c) 1991-2010 by Ollivier ROBERT
** A distribuer selon les regles de la GNU GPL General Public Licence
** Voir le fichier COPYING fourni.
**
**/
#ifndef lint
static const char * rcsid = "@(#) $Id: auth.c,v 0dcc27d2f900 2009/12/01 17:37:46 roberto $";
#endif
#include "config.h" /* GNU configure */
/* fichier de configuration */
#include "conf.h"
static int pam_pwcheck (struct passwd *calife, char * user_to_be, \
char * user_pass, int l_size);
static int local_pwcheck (struct passwd *calife, char * user_to_be, \
char * user_pass, int l_size);
static void get_user_passwd(char * user_pass, int l_size);
/** authenticate_user
**
** Demande et verifie le mot de passe pour l'utilisateur name
** Si name == root on ne fait rien.
**
** Parametres : name char * nom de l'utilisateur
** user_to_be char * qui va-t-on devenir
** this_time char * quand ?
** tty char * sur quel tty
**
** Retourne : neant
**
** Algo:
** si WITH_PAM est définit
** on essaie auth_pam()
** si ça plante, on continue avec un warning
** sinon retour ok
** fin
** vérification mdp
**
**/
void
authenticate_user (char * who, char * user_to_be, char * when, char * tty)
{
int i = 0, rval, md5_here = 0;
size_t l_size = 0;
struct passwd * calife;
char got_pass = AUTH_ERR;
char * pt_pass, * pt_enc,
* user_pass = NULL, * enc_pass = NULL, salt [10];
/*
* returns long usually
*/
#ifdef HAVE_WORKING_SYSCONF
l_size = (size_t) sysconf (_SC_LINE_MAX);
#else
l_size = MAX_STRING;
#endif /* HAVE_WORKING_SYSCONF */
user_pass = (char *) xalloc (l_size);
enc_pass = (char *) xalloc (l_size);
/*
* become root again
*/
GET_ROOT;
calife = getpwnam (who); /* null or locked password */
RELEASE_ROOT;
if (calife == NULL)
die (1, "Bad pw data at line %d", __LINE__);
#ifdef WITH_PAM
got_pass = pam_pwcheck (calife, user_to_be, user_pass, l_size);
#endif
if (got_pass != AUTH_OK)
got_pass = local_pwcheck (calife, user_to_be, user_pass, l_size);
MESSAGE_1 ("Auth process returned %d\n", got_pass);
if (got_pass == AUTH_NULL)
{
syslog (LOG_AUTH | LOG_ERR, "NULL CALIFE %s to %s on %s", who, \
user_to_be, tty);
closelog ();
die (10, "Sorry.\n");
}
if (got_pass == AUTH_ERR)
{
syslog (LOG_AUTH | LOG_ERR, "BAD CALIFE %s to %s on %s", who, user_to_be, tty);
closelog ();
die (9, "Sorry.\n");
}
if (got_pass == AUTH_BADP)
{
syslog (LOG_AUTH|LOG_ERR, "GARBLED PASSWORD %s to unknown %s on%s",\
who, user_to_be, tty);
die (8, "Bad password string.\n");
}
free (user_pass);
free (enc_pass);
}
/** local_pwcheck
**
** Private method to check user password against local database
**
** Parameters: calife struct passwd * requesting user
** user_to_be char * target user
** user_pass chat * user password
** l_size int maximum size for password
**
** Returns: got_pass Whether we got authenticated or not
**/
static
int local_pwcheck (struct passwd * calife, char * user_to_be, \
char * user_pass, int l_size)
{
char * pt_pass, * who;
int i, rval, got_pass = AUTH_ERR, md5_here = 0;
#if defined (HAVE_SHADOW_H) && defined (HAVE_GETSPNAM) && !defined(UNUSED_SHADOW)
struct spwd * scalife;
#endif
MESSAGE_1 ("Testing w/o PAM with got_pass = %d\n", got_pass);
#if defined (HAVE_SHADOW_H) && defined (HAVE_GETSPNAM) && !defined(UNUSED_SHADOW)
who = calife->pw_name;
GET_ROOT;
scalife = getspnam (who); /* null or locked password */
RELEASE_ROOT;
/*
* Goal is to manipulate only "calife", not both so if "scalife" is
* valid, copy "scalife" interesting data into "calife"
*/
if (scalife)
{
calife->pw_passwd =
(char *) xalloc (strlen (scalife->sp_pwdp) + 1);
strcpy (calife->pw_passwd, scalife->sp_pwdp);
}
#endif /* HAVE_SHADOW_H */
MESSAGE ("Not using PAM.\n");
if ((*(calife->pw_passwd)) == '\0' || (*(calife->pw_passwd)) == '*')
return (AUTH_NULL);
if (getuid () != 0)
{
char * pt_pass, * pt_enc,
* user_pass, * enc_pass, salt [10];
user_pass = (char *) xalloc (l_size);
enc_pass = (char *) xalloc (l_size);
/*
* cope with MD5 based crypt(3)
*/
if (!strncmp (calife->pw_passwd, "$1$", 3)) /* MD5 */
{
char * pp = (char *) xalloc (strlen (calife->pw_passwd) + 1);
char * md5_salt;
char * md5_pass;
strcpy (pp, calife->pw_passwd + 3);
md5_salt = strtok (pp, "$");
md5_pass = strtok (NULL, "$");
if (md5_pass == NULL ||
md5_salt == NULL ||
(strlen (md5_salt) > 8)) /* garbled password */
return (AUTH_BADP);
MESSAGE_1 ("MD5 password found, salt=%s\n", md5_salt);
strcpy (salt, md5_salt);
free (pp);
}
else
{
strncpy (salt, calife->pw_passwd, 2);
salt [2] = '\0';
}
for ( i = 0; i < MAX_ATTEMPTS; i ++ )
{
get_user_passwd (user_pass, l_size);
/*
* At this point, either we have a password or
* it has died already
*/
pt_enc = (char *) crypt (user_pass, calife->pw_passwd);
/*
* Wipe out the cleartext password
*/
memset (user_pass, '\0', l_size);
/*
* Move from the static buffer intoa safe location of our own
*/
memset (enc_pass, '\0', l_size);
strcpy (enc_pass, pt_enc);
/*
* assumes standard crypt(3)
*/
if (!strcmp (enc_pass, calife->pw_passwd))
{
got_pass = AUTH_OK;
break;
}
} /* for */
} /* end if for getuid() */
return (got_pass);
}
/** pam_pwcheck
**
** Private method to check user password against PAM backend.
**
** Parameters: calife struct passwd * target user
** user_to_be char * target user
** user_pass chat * user password
** l_size int maximum size for password
**
** Returns: whether the password was obtained through PAM or not
** (including failure in PAM process)
**/
static
int pam_pwcheck (struct passwd *calife, char * user_to_be, char * user_pass,\
int l_size)
{
char * pt_pass, * who;
int i, rval, got_pass = AUTH_ERR;
#ifdef WITH_PAM
who = calife->pw_name;
if (getuid () != 0)
{
MESSAGE ("Trying PAM\n");
for ( i = 0; i < MAX_ATTEMPTS; i++ )
{
get_user_passwd (user_pass, l_size);
/*
* At this point, either we have a password or
* it has died already
*/
MESSAGE ("Testing auth with PAM.\n");
rval = auth_pam (&calife, user_pass);
MESSAGE_1 ("PAM auth_pam returned %d\n", rval);
if (rval)
{
syslog (LOG_AUTH | LOG_ERR, "PAM failed with code %d for %s", rval, who);
/*
* Check return value:
* - 0: auth succeeded
* - >0: auth failed.
*/
/* Fallback to previous methods? */
}
else
{
syslog (LOG_AUTH | LOG_INFO, "PAM auth succeeded for %s", who);
got_pass = AUTH_OK;
break;
}
} /* end for */
}
else
got_pass = AUTH_OK;
#endif
return got_pass;
}
/** get_user_passwd
**
** When not using PAM, get the user's password with getpass/getpassphrase
**
** Parameters: user_pass char * password
** l_size int maximum size
**
** Returns: nothing
**/
static
void get_user_passwd(char * user_pass, int l_size)
{
char * pt_pass;
/* XXX Solaris 10
* Solaris 5.10 (and maybe before) truncate getpass() entry
* to 8 bytes, use getpassphrase(3) instead
*
* Use getpassphrase(3) if available
*/
#ifdef HAVE_GETPASSPHRASE
pt_pass = (char *) getpassphrase ("Password:");
#else
pt_pass = (char *) getpass ("Password:");
#endif /* HAVE_GETPASSPHRASE */
/*
* XXX don't assume getpass(3) will check the buffer
* length. Linux glibc apparently lacks such checking and
* will happily segfault if the previous entered password
* was too big.
* cf. <URL:http://www.securityfocus.com/archive/1/355510>
*/
if (pt_pass == NULL)
die(1, "Corrupted or too long password");
memset (user_pass, '\0', l_size);
/*
* Be a bit more careful there
*/
strncpy (user_pass, pt_pass, l_size);
user_pass[l_size - 1] = '\0';
}
/*
get_user_data
calife
scalife
get_user_password
(select getpass or getpassphrase)
check_passwd
if_pam
auth_pam
else
(select encryption method based on sig $nn$salt$passwd)
end
*/
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