shadow/lib/pwauth.c

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/*
* Copyright 1992 - 1994, Julianne Frances Haugh
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of Julianne F. Haugh nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY JULIE HAUGH AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL JULIE HAUGH OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <config.h>
#ifndef USE_PAM
#ident "$Id: pwauth.c,v 1.23 2006/06/24 13:17:18 kloczek Exp $"
#include <errno.h>
#include <fcntl.h>
#include <signal.h>
#include <stdio.h>
#include <sys/types.h>
#include <unistd.h>
#include "prototypes.h"
#include "defines.h"
#include "pwauth.h"
#include "getdef.h"
#ifdef SKEY
#include <skey.h>
#endif
#ifdef __linux__ /* standard password prompt by default */
static const char *PROMPT = gettext_noop ("Password: ");
#else
static const char *PROMPT = gettext_noop ("%s's Password: ");
#endif
int wipe_clear_pass = 1;
char *clear_pass = NULL;
/*
* pw_auth - perform getpass/crypt authentication
*
* pw_auth gets the user's cleartext password and encrypts it
* using the salt in the encrypted password. The results are
* compared.
*/
int
pw_auth (const char *cipher, const char *user, int reason, const char *input)
{
char prompt[1024];
char *clear = NULL;
const char *cp;
int retval;
#ifdef SKEY
int use_skey = 0;
char challenge_info[40];
struct skey skey;
#endif
/*
* There are programs for adding and deleting authentication data.
*/
if (reason == PW_ADD || reason == PW_DELETE)
return 0;
/*
* There are even programs for changing the user name ...
*/
if (reason == PW_CHANGE && input != (char *) 0)
return 0;
/*
* WARNING:
*
* When we change a password and we are root, we don't prompt.
* This is so root can change any password without having to
* know it. This is a policy decision that might have to be
* revisited.
*/
if (reason == PW_CHANGE && getuid () == 0)
return 0;
/*
* WARNING:
*
* When we are logging in a user with no ciphertext password,
* we don't prompt for the password or anything. In reality
* the user could just hit <ENTER>, so it doesn't really
* matter.
*/
if (cipher == (char *) 0 || *cipher == '\0')
return 0;
#ifdef SKEY
/*
* If the user has an S/KEY entry show them the pertinent info
* and then we can try validating the created cyphertext and the SKEY.
* If there is no SKEY information we default to not using SKEY.
*/
# ifdef SKEY_BSD_STYLE
/*
* Some BSD updates to the S/KEY API adds a fourth parameter; the
* sizeof of the challenge info buffer.
*/
# define skeychallenge(s,u,c) skeychallenge(s,u,c,sizeof(c))
# endif
if (skeychallenge (&skey, user, challenge_info) == 0)
use_skey = 1;
#endif
/*
* Prompt for the password as required. FTPD and REXECD both
* get the cleartext password for us.
*/
if (reason != PW_FTP && reason != PW_REXEC && !input) {
if (!(cp = getdef_str ("LOGIN_STRING")))
cp = _(PROMPT);
#ifdef SKEY
if (use_skey)
printf ("[%s]\n", challenge_info);
#endif
snprintf (prompt, sizeof prompt, cp, user);
clear = getpass (prompt);
if (!clear) {
static char c[1];
c[0] = '\0';
clear = c;
}
input = clear;
}
/*
* Convert the cleartext password into a ciphertext string.
* If the two match, the return value will be zero, which is
* SUCCESS. Otherwise we see if SKEY is being used and check
* the results there as well.
*/
retval = strcmp (pw_encrypt (input, cipher), cipher);
#ifdef SKEY
/*
* If (1) The password fails to match, and
* (2) The password is empty and
* (3) We are using OPIE or S/Key, then
* ...Re-prompt, with echo on.
* -- AR 8/22/1999
*/
if (retval && !input[0] && (use_skey)) {
clear = getpass (prompt);
if (!clear) {
static char c[1];
c[0] = '\0';
clear = c;
}
input = clear;
}
if (retval && use_skey) {
int passcheck = -1;
if (skeyverify (&skey, input) == 0)
passcheck = skey.n;
if (passcheck > 0)
retval = 0;
}
#endif
/*
* Things like RADIUS authentication may need the password -
* if the external variable wipe_clear_pass is zero, we will
* not wipe it (the caller should wipe clear_pass when it is
* no longer needed). --marekm
*/
clear_pass = clear;
if (wipe_clear_pass && clear && *clear)
strzero (clear);
return retval;
}
#endif /* !USE_PAM */