shadow/libmisc/valid.c
nekral-guest c7302b61ef Make sure every source files are distributed with a copyright and license.
Files with no license use the default 3-clauses BSD license. The copyright
were mostly not recorded; they were updated according to the Changelog.
"Julianne Frances Haugh and contributors" changed to "copyright holders
and contributors".
2008-04-27 00:40:09 +00:00

102 lines
3.4 KiB
C

/*
* Copyright (c) 1989 - 1993, Julianne Frances Haugh
* Copyright (c) 1996 - 1999, Marek Michałkiewicz
* Copyright (c) 2003 - 2005, Tomasz Kłoczko
* Copyright (c) 2007 , 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.
*/
int valid (const char *password, const struct passwd *ent)
{
const char *encrypted;
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 (ent->pw_name && !ent->pw_passwd[0]) {
if (!password[0])
return (1); /* user entered nothing */
else
return (0); /* user entered something! */
}
/*
* If there is no entry then we need a salt to use.
*/
if (ent->pw_name == (char *) 0 || ent->pw_passwd[0] == '\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 (ent->pw_name && strcmp (encrypted, ent->pw_passwd) == 0)
return (1);
else
return (0);
}