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/*
* Copyright (c) 1992 - 1994, Julianne Frances Haugh
* Copyright (c) 1996 - 2000, Marek Michałkiewicz
* Copyright (c) 2003 - 2006, Tomasz Kłoczko
* Copyright (c) 2008 - 2009, Nicolas François
* 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. The name of the copyright holders or contributors may not be used to
* endorse or promote products derived from this software without
* specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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 THE COPYRIGHT
* HOLDERS 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 "$Id$"
#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
bool wipe_clear_pass = true;
/*@null@*/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,
/*@null@*/const char *input)
{
char prompt[1024];
char *clear = NULL;
const char *cp;
const char *encrypted;
int retval;
#ifdef SKEY
bool use_skey = false;
char challenge_info[40];
struct skey skey;
#endif
/*
* There are programs for adding and deleting authentication data.
*/
if ((PW_ADD == reason) || (PW_DELETE == reason)) {
return 0;
}
/*
* There are even programs for changing the user name ...
*/
if ((PW_CHANGE == reason) && (NULL != input)) {
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 ((PW_CHANGE == reason) && (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 ((NULL == cipher) || ('\0' == *cipher)) {
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 = true;
}
#endif
/*
* Prompt for the password as required. FTPD and REXECD both
* get the cleartext password for us.
*/
if ((PW_FTP != reason) && (PW_REXEC != reason) && (NULL == input)) {
cp = getdef_str ("LOGIN_STRING");
if (NULL == cp) {
cp = _(PROMPT);
}
#ifdef SKEY
if (use_skey) {
printf ("[%s]\n", challenge_info);
}
#endif
snprintf (prompt, sizeof prompt, cp, user);
clear = getpass (prompt);
if (NULL == 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.
*/
encrypted = pw_encrypt (input, cipher);
if (NULL != encrypted) {
retval = strcmp (encrypted, cipher);
} else {
retval = -1;
}
#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 ((0 != retval) && ('\0' == input[0]) && use_skey) {
clear = getpass (prompt);
if (NULL == clear) {
static char c[1];
c[0] = '\0';
clear = c;
}
input = clear;
}
if ((0 != 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 && (NULL != clear) && ('\0' != *clear)) {
strzero (clear);
}
return retval;
}
#else /* !USE_PAM */
extern int errno; /* warning: ANSI C forbids an empty source file */
#endif /* !USE_PAM */
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