freebsd-dev/lib/libcrypt/crypt.c
Dag-Erling Smørgrav 5280a31478 r261913 broke DES passwords, because the only way they could work,
since they don't have an easily recognizable signature, was if they
were the default.  This commit rewrites crypt_set_format(3) etc to
address this:

 - Use a pointer instead of an index to identify the default format.
   This pointer is initialized at compile time to point to the first
   first element in the list of supported formats, eliminating the
   need for crypt_setdefault().  Using a pointer also simplifies
   iterating through the list.

 - Associate DES with the magic string "_", which takes care of the
   Extended DES format.

 - Finally, as a special case, if the salt does not match any known
   magic string but matches ^[./0-9A-Za-z]{13}$, it is assumed to be a
   DES password and is passed on to crypt_des().

MFC after:	1 week
2014-04-26 11:50:25 +00:00

117 lines
3.3 KiB
C

/*-
* Copyright (c) 1999 Mark Murray
* Copyright (c) 2014 Dag-Erling Smørgrav
* 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.
*
* THIS SOFTWARE IS PROVIDED BY MARK MURRAY 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 MARK MURRAY 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 <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/types.h>
#include <libutil.h>
#include <string.h>
#include <unistd.h>
#include "crypt.h"
/*
* List of supported crypt(3) formats. The first element in the list will
* be the default.
*/
static const struct crypt_format {
const char *const name;
char *(*const func)(const char *, const char *);
const char *const magic;
} crypt_formats[] = {
/* default format */
{ "sha512", crypt_sha512, "$6$" },
/* other supported formats */
{ "md5", crypt_md5, "$1$" },
#ifdef HAS_BLOWFISH
{ "blf", crypt_blowfish, "$2" },
#endif
{ "nth", crypt_nthash, "$3$" },
{ "sha256", crypt_sha256, "$5$" },
#ifdef HAS_DES
{ "des", crypt_des, "_" },
#endif
/* sentinel */
{ NULL, NULL, NULL }
};
static const struct crypt_format *crypt_format = &crypt_formats[0];
#define DES_SALT_ALPHABET \
"./0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"
/*
* Returns the name of the currently selected format.
*/
const char *
crypt_get_format(void)
{
return (crypt_format->name);
}
/*
* Selects the format to use for subsequent crypt(3) invocations.
*/
int
crypt_set_format(const char *format)
{
const struct crypt_format *cf;
for (cf = crypt_formats; cf->name != NULL; ++cf) {
if (strcasecmp(cf->name, format) == 0) {
crypt_format = cf;
return (1);
}
}
return (0);
}
/*
* Hash the given password with the given salt. If the salt begins with a
* magic string (e.g. "$6$" for sha512), the corresponding format is used;
* otherwise, the currently selected format is used.
*/
char *
crypt(const char *passwd, const char *salt)
{
const struct crypt_format *cf;
for (cf = crypt_formats; cf->name != NULL; ++cf)
if (cf->magic != NULL && strstr(salt, cf->magic) == salt)
return (cf->func(passwd, salt));
#ifdef HAS_DES
if (strlen(salt) == 13 && strspn(salt, DES_SALT_ALPHABET) == 13)
return (crypt_des(passwd, salt));
#endif
return (crypt_format->func(passwd, salt));
}