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path: root/daemon/verify.c
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/* GDM - The Gnome Display Manager
 * Copyright (C) 1998, 1999 Martin Kasper Petersen <mkp@SunSITE.auc.dk>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <syslog.h>
#include <pwd.h>
#include <glib.h>
#include <crypt.h>
#include <config.h>
#include <gnome.h>

#ifdef HAVE_PAM
  #include <security/pam_appl.h>
#endif /* HAVE_PAM */

#ifdef HAVE_SHADOW
  #include <shadow.h>
#endif /* HAVE_SHADOW */

#include "gdm.h"

static const gchar RCSid[]="$Id$";

extern void gdm_abort(const char*, ...);
extern void gdm_debug(const char*, ...);
extern void gdm_error(const char*, ...);
extern gchar *gdm_slave_greeter_ctl(gchar cmd, gchar *str);

extern gboolean GdmVerboseAuth;
extern gboolean GdmAllowRoot;

gchar *gdm_verify_user (gchar *display);
void gdm_verify_cleanup (void);


#ifdef HAVE_PAM

pam_handle_t *pamh;


static gint 
gdm_verify_pam_conv(int num_msg, const struct pam_message **msg,
		    struct pam_response **resp,
		    void *appdata_ptr)
{
    gint replies = 0;
    struct pam_response *reply = NULL;
    gchar *s;
    
    reply=g_new0(struct pam_response, num_msg);

    if(!reply) 
	return PAM_CONV_ERR;
    
    for(replies=0; replies<num_msg; replies++) {

	switch(msg[replies]->msg_style) {

	case PAM_PROMPT_ECHO_ON:
	    s=gdm_slave_greeter_ctl(GDM_PROMPT, (gchar *)msg[replies]->msg);
	    reply[replies].resp_retcode=PAM_SUCCESS;
	    reply[replies].resp=g_strdup(s);
	    g_free(s);
	    break;

	case PAM_PROMPT_ECHO_OFF:
	    s=gdm_slave_greeter_ctl(GDM_NOECHO, (gchar *)msg[replies]->msg);
	    reply[replies].resp_retcode=PAM_SUCCESS;
	    reply[replies].resp=g_strdup(s);
	    g_free(s);
	    break;

	case PAM_ERROR_MSG:
	case PAM_TEXT_INFO:
	    gdm_slave_greeter_ctl(GDM_MSGERR, (gchar *)msg[replies]->msg);
	    reply[replies].resp_retcode=PAM_SUCCESS;
	    reply[replies].resp=NULL;
	    break;

	default:
	    g_free(reply);
	    return PAM_CONV_ERR;
	}

    }

    *resp=reply;
    return(PAM_SUCCESS);
}


static struct pam_conv pamc = {
    &gdm_verify_pam_conv,
    NULL
};


gchar *
gdm_verify_user (gchar *display) 
{
    gint pamerr, i;
    gchar *login;
    gchar **pamenv;
    struct passwd *pwent;

    login=gdm_slave_greeter_ctl(GDM_PROMPT, _("Login:"));

    if(!login)
	return(NULL);

    pwent=getpwnam(login);

    if(!pwent) {
	gdm_error(_("Couldn't authenticate %s"), login);

	if(GdmVerboseAuth)
	    gdm_slave_greeter_ctl(GDM_MSGERR, _("User unknown"));

	return(NULL);
    }

    if(GdmAllowRoot && pwent->pw_uid == 0) {
	gdm_error(_("Root login disallowed on display '%s'"), display);

	if(GdmVerboseAuth)
	    gdm_slave_greeter_ctl(GDM_MSGERR, _("Root login disallowed"));

	return(NULL);
    }

    if((pamerr=pam_start("gdm", login, &pamc, &pamh)) != PAM_SUCCESS) {
	gdm_error(_("Can't find /etc/pam.d/gdm!"));
    }
    
    if((pamerr=pam_set_item(pamh, PAM_TTY, display)) != PAM_SUCCESS) {
	gdm_error(_("Can't set PAM_TTY=%s"), ":0");
	goto pamerr;
    }
    
    if((pamerr=pam_authenticate(pamh, 0)) != PAM_SUCCESS) {
	gdm_error(_("Couldn't authenticate %s"), login);
	goto pamerr;
    }

    if((pamerr=pam_acct_mgmt(pamh, 0)) != PAM_SUCCESS) {
	gdm_error(_("Couldn't set acct. mgmt for %s"), login);
	goto pamerr;
    }

    if((pamerr=pam_setcred(pamh, 0)) != PAM_SUCCESS) {
	gdm_error(_("Couldn't set credentials for %s"), login);
	goto pamerr;
    }

    if((pamerr=pam_open_session(pamh, 0)) != PAM_SUCCESS) {
	gdm_error(_("Couldn't open session for %s"), login);
	goto pamerr;
    }

    if((pamenv=pam_getenvlist(pamh))) {
	for(i=0 ; pamenv[i] ; i++) {
            putenv(pamenv[i]);
        }
    }

    return(login);

 pamerr:

    if(GdmVerboseAuth)
	gdm_slave_greeter_ctl(GDM_MSGERR, (gchar *)pam_strerror(pamh, pamerr));

    pam_end(pamh, pamerr);
    pamh=NULL;

    /* Workaround to avoid gdm messages being logged as PAM_pwdb */
    closelog();
    openlog("gdm", LOG_PID, LOG_DAEMON);

    return(NULL);
}

#else /* HAVE_PAM */

gchar *
gdm_verify_user (gchar *display) 
{
    gchar *login, *passwd, *ppasswd;
    struct passwd *pwent;

#ifdef HAVE_SHADOW
    struct spwd *sp;
#endif

    login=gdm_slave_greeter_ctl(GDM_PROMPT, _("Login:"));
    pwent=getpwnam(login);

    if(!pwent) {
	gdm_error(_("Couldn't authenticate %s"), login);

	if(GdmVerboseAuth)
	    gdm_slave_greeter_ctl(GDM_MSGERR, _("User unknown"));

	return(NULL);
    }

    if(GdmAllowRoot && pwent->pw_uid == 0) {
	gdm_error(_("Root login disallowed on display '%s'"), display);

	if(GdmVerboseAuth)
	    gdm_slave_greeter_ctl(GDM_MSGERR, _("Root login disallowed"));

	return(NULL);
    }	

    ppasswd=!pwent ? NULL : pwent->pw_passwd;

#ifdef HAVE_SHADOW
    sp=getspnam(login);

    if(sp)
        ppasswd=sp->sp_pwdp;

    endspent();
#endif /* HAVE_SHADOW */

    passwd=gdm_slave_greeter_ctl(GDM_NOECHO, _("Password:"));

    if (!passwd || !ppasswd || strcmp(crypt(passwd, ppasswd), ppasswd)) {

	if(GdmVerboseAuth)
	    gdm_slave_greeter_ctl(GDM_MSGERR, _("Incorrect password"));

	return(NULL);
    }

    return(login);
}
#endif /* HAVE_PAM */


void 
gdm_verify_cleanup (void)
{
#ifdef HAVE_PAM
    gdm_debug("gdm_verify_cleanup: Closing session %d", pamh);

    if(pamh) {
	pam_close_session(pamh, 0);
	pam_end(pamh, PAM_SUCCESS);
	pamh=NULL;
    }

    /* Workaround to avoid gdm messages being logged as PAM_pwdb */
    closelog();
    openlog("gdm", LOG_PID, LOG_DAEMON);
#endif /* HAVE_PAM */
}

/* EOF */