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/*
* Copyright (C) 2008 Red Hat, Inc.
* Copyright (C) 2009-2010 Andrew Psaltis <ampsaltis@gmail.com>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General
* Public License along with this library; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place, Suite 330,
* Boston, MA 02111-1307, USA.
*
* Authors: Andrew Psaltis <ampsaltis@gmail.com>, based on
* polkitagenthelper.c which was written by
* David Zeuthen <davidz@redhat.com>
*/
#include "config.h"
#include "polkitagenthelperprivate.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <syslog.h>
#include <shadow.h>
#include <grp.h>
#include <pwd.h>
#include <time.h>
#include <polkit/polkit.h>
static gboolean shadow_authenticate (struct spwd *shadow);
int
main (int argc, char *argv[])
{
struct spwd *shadow;
const char *user_to_auth;
char *cookie = NULL;
time_t now;
/* clear the entire environment to avoid attacks with
libraries honoring environment variables */
if (_polkit_clearenv () != 0)
goto error;
/* set a minimal environment */
setenv ("PATH", "/usr/sbin:/usr/bin:/sbin:/bin", 1);
/* check that we are setuid root */
if (geteuid () != 0)
{
fprintf (stderr, "polkit-agent-helper-1: needs to be setuid root\n");
goto error;
}
openlog ("polkit-agent-helper-1", LOG_CONS | LOG_PID, LOG_AUTHPRIV);
/* check for correct invocation */
if (!(argc == 2 || argc == 3))
{
syslog (LOG_NOTICE, "inappropriate use of helper, wrong number of arguments [uid=%d]", getuid ());
fprintf (stderr, "polkit-agent-helper-1: wrong number of arguments. This incident has been logged.\n");
goto error;
}
if (getuid () != 0)
{
/* check we're running with a non-tty stdin */
if (isatty (STDIN_FILENO) != 0)
{
syslog (LOG_NOTICE, "inappropriate use of helper, stdin is a tty [uid=%d]", getuid ());
fprintf (stderr, "polkit-agent-helper-1: inappropriate use of helper, stdin is a tty. This incident has been logged.\n");
goto error;
}
}
user_to_auth = argv[1];
cookie = read_cookie (argc, argv);
if (!cookie)
goto error;
#ifdef PAH_DEBUG
fprintf (stderr, "polkit-agent-helper-1: user to auth is '%s'.\n", user_to_auth);
#endif /* PAH_DEBUG */
/* Ask shadow about the user requesting authentication */
shadow = getspnam (user_to_auth);
if (shadow == NULL)
{
syslog (LOG_NOTICE, "shadow file data information request for user '%s' [uid=%d] failed", user_to_auth, getuid ());
fprintf(stderr, "polkit-agent-helper-1: could not get shadow information for '%s'", user_to_auth);
goto error;
}
/* Check the user's identity */
if (shadow_authenticate (shadow) == FALSE)
{
syslog (LOG_NOTICE, "authentication failure [uid=%d] trying to authenticate '%s'", getuid (), user_to_auth);
fprintf (stderr, "polkit-agent-helper-1: authentication failure. This incident has been logged.\n");
goto error;
}
/* Check whether the user's password has expired */
now = time (NULL);
if (shadow->sp_max >= 0 && (shadow->sp_lstchg + shadow->sp_max) * 60 * 60 * 24 <= now)
{
syslog (LOG_NOTICE, "password expired for user '%s' [uid=%d] trying to authenticate", user_to_auth, getuid ());
fprintf (stderr, "polkit-agent-helper-1: authorization failure. This incident has been logged.\n");
goto error;
}
/* Check whether the user's password has aged (and account expired along
* with it)
*/
if (shadow->sp_inact >= 0 && (shadow->sp_lstchg + shadow->sp_max + shadow->sp_inact) * 60 * 60 * 24 <= now)
{
syslog (LOG_NOTICE, "password aged for user '%s' [uid=%d] trying to authenticate", user_to_auth, getuid ());
fprintf (stderr, "polkit-agent-helper-1: authorization failure. This incident has been logged.\n");
goto error;
}
/* Check whether the user's account has expired */
if (shadow->sp_expire >= 0 && shadow->sp_expire * 60 * 60 * 24 <= now)
{
syslog (LOG_NOTICE, "account expired for user '%s' [uid=%d] trying to authenticate", user_to_auth, getuid ());
fprintf (stderr, "polkit-agent-helper-1: authorization failure. This incident has been logged.\n");
goto error;
}
#ifdef PAH_DEBUG
fprintf (stderr, "polkit-agent-helper-1: sending D-Bus message to PolicyKit daemon\n");
#endif /* PAH_DEBUG */
/* now send a D-Bus message to the PolicyKit daemon that
* includes a) the cookie; and b) the user we authenticated
*/
if (!send_dbus_message (cookie, user_to_auth))
{
#ifdef PAH_DEBUG
fprintf (stderr, "polkit-agent-helper-1: error sending D-Bus message to PolicyKit daemon\n");
#endif /* PAH_DEBUG */
goto error;
}
free (cookie);
#ifdef PAH_DEBUG
fprintf (stderr, "polkit-agent-helper-1: successfully sent D-Bus message to PolicyKit daemon\n");
#endif /* PAH_DEBUG */
fprintf (stdout, "SUCCESS\n");
flush_and_wait ();
return 0;
error:
free (cookie);
fprintf (stdout, "FAILURE\n");
flush_and_wait ();
return 1;
}
static gboolean
shadow_authenticate (struct spwd *shadow)
{
char passwd[512], *crypt_pass;
fprintf (stdout, "PAM_PROMPT_ECHO_OFF password:\n");
fflush (stdout);
usleep (10 * 1000); /* since fflush(3) seems buggy */
if (fgets (passwd, sizeof (passwd), stdin) == NULL)
goto error;
if (strlen (passwd) > 0 && passwd[strlen (passwd) - 1] == '\n')
passwd[strlen (passwd) - 1] = '\0';
/* Use the encrypted password as the salt, according to the crypt(3) man page,
* it will perform whatever encryption method is specified in /etc/shadow
*/
crypt_pass = crypt (passwd, shadow->sp_pwdp);
if (crypt_pass == NULL)
goto error;
if (strcmp (shadow->sp_pwdp, crypt (passwd, shadow->sp_pwdp)) != 0)
goto error;
return 1;
error:
return 0;
}
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