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/*
* Copyright (c) 1989 - 1993, Julianne Frances Haugh
* Copyright (c) 1996 - 1999, Marek Michałkiewicz
* Copyright (c) 2003 - 2005, Tomasz Kłoczko
* Copyright (c) 2007 - 2008, 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>
#ident "$Id$"
#include <sys/types.h>
#include <stdio.h>
#include "prototypes.h"
#include "defines.h"
#include <pwd.h>
/*
* valid - compare encrypted passwords
*
* Valid() compares the DES encrypted password from the password file
* against the password which the user has entered after it has been
* encrypted using the same salt as the original. Entries which do
* not have a password file entry have a NULL pw_name field and this
* is used to indicate that a dummy salt must be used to encrypt the
* password anyway.
*/
bool valid (const char *password, const struct passwd *ent)
{
const char *encrypted;
/*@observer@*/const char *salt;
/*
* Start with blank or empty password entries. Always encrypt
* a password if no such user exists. Only if the ID exists and
* the password is really empty do you return quickly. This
* routine is meant to waste CPU time.
*/
if ((NULL != ent->pw_name) && ('\0' == ent->pw_passwd[0])) {
if ('\0' == password[0]) {
return true; /* user entered nothing */
} else {
return false; /* user entered something! */
}
}
/*
* If there is no entry then we need a salt to use.
*/
if ((NULL == ent->pw_name) || ('\0' == ent->pw_passwd[0])) {
salt = "xx";
} else {
salt = ent->pw_passwd;
}
/*
* Now, perform the encryption using the salt from before on
* the users input. Since we always encrypt the string, it
* should be very difficult to determine if the user exists by
* looking at execution time.
*/
encrypted = pw_encrypt (password, salt);
/*
* One last time we must deal with there being no password file
* entry for the user. We use the pw_name == NULL idiom to
* cause non-existent users to not be validated.
*/
if ( (NULL != ent->pw_name)
&& (NULL != encrypted)
&& (strcmp (encrypted, ent->pw_passwd) == 0)) {
return true;
} else {
return false;
}
}
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