98 lines
3.3 KiB
C
98 lines
3.3 KiB
C
/*
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* Copyright 1989 - 1993, Julianne Frances Haugh
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of Julianne F. Haugh nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY JULIE HAUGH AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL JULIE HAUGH OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <config.h>
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#ident "$Id$"
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#include <sys/types.h>
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#include <stdio.h>
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#include "prototypes.h"
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#include "defines.h"
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#include <pwd.h>
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/*
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* valid - compare encrypted passwords
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*
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* Valid() compares the DES encrypted password from the password file
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* against the password which the user has entered after it has been
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* encrypted using the same salt as the original. Entries which do
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* not have a password file entry have a NULL pw_name field and this
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* is used to indicate that a dummy salt must be used to encrypt the
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* password anyway.
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*/
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int valid (const char *password, const struct passwd *ent)
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{
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const char *encrypted;
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const char *salt;
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/*
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* Start with blank or empty password entries. Always encrypt
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* a password if no such user exists. Only if the ID exists and
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* the password is really empty do you return quickly. This
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* routine is meant to waste CPU time.
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*/
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if (ent->pw_name && !ent->pw_passwd[0]) {
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if (!password[0])
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return (1); /* user entered nothing */
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else
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return (0); /* user entered something! */
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}
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/*
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* If there is no entry then we need a salt to use.
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*/
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if (ent->pw_name == (char *) 0 || ent->pw_passwd[0] == '\0') {
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salt = "xx";
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} else {
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salt = ent->pw_passwd;
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}
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/*
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* Now, perform the encryption using the salt from before on
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* the users input. Since we always encrypt the string, it
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* should be very difficult to determine if the user exists by
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* looking at execution time.
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*/
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encrypted = pw_encrypt (password, salt);
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/*
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* One last time we must deal with there being no password file
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* entry for the user. We use the pw_name == NULL idiom to
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* cause non-existent users to not be validated.
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*/
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if (ent->pw_name && strcmp (encrypted, ent->pw_passwd) == 0)
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return (1);
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else
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return (0);
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}
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