shadow/libmisc/valid.c
Serge Hallyn f93cf255d4 Update licensing info
Closes #238

Update all files to list SPDX license shortname.  Most files are
BSD 3 clause license.

The exceptions are:

serge@sl ~/src/shadow$ git grep SPDX-License | grep -v BSD-3-Clause
contrib/atudel:# SPDX-License-Identifier: BSD-4-Clause
lib/tcbfuncs.c: * SPDX-License-Identifier: 0BSD
libmisc/salt.c: * SPDX-License-Identifier: Unlicense
src/login_nopam.c: * SPDX-License-Identifier: Unlicense
src/nologin.c: * SPDX-License-Identifier: BSD-2-Clause
src/vipw.c: * SPDX-License-Identifier: GPL-2.0-or-later

Signed-off-by: Serge Hallyn <serge@hallyn.com>
2021-12-23 19:36:50 -06:00

83 lines
2.1 KiB
C

/*
* SPDX-FileCopyrightText: 1989 - 1993, Julianne Frances Haugh
* SPDX-FileCopyrightText: 1996 - 1999, Marek Michałkiewicz
* SPDX-FileCopyrightText: 2003 - 2005, Tomasz Kłoczko
* SPDX-FileCopyrightText: 2007 - 2008, Nicolas François
*
* SPDX-License-Identifier: BSD-3-Clause
*/
#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;
}
}