freebsd-skq/lib/libcrypt/crypt.c
Ed Schouten 5f521d7ba7 Make libcrypt thread-safe. Add crypt_r(3).
glibc has a pretty nice function called crypt_r(3), which is nothing
more than crypt(3), but thread-safe. It accomplishes this by introducing
a 'struct crypt_data' structure that contains a buffer that is large
enough to hold the resulting string.

Let's go ahead and also add this function. It would be a shame if a
useful function like this wouldn't be usable in multithreaded apps.
Refactor crypt.c and all of the backends to no longer declare static
arrays, but write their output in a provided buffer.

There is no need to do any buffer length computation here, as we'll just
need to ensure that 'struct crypt_data' is large enough, which it is.
_PASSWORD_LEN is defined to 128 bytes, but in this case I'm picking 256,
as this is going to be part of the actual ABI.

Differential Revision:	https://reviews.freebsd.org/D7306
2016-08-10 15:16:28 +00:00

141 lines
3.9 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 default algorithm is the last entry in the list (second-to-last
* array element since the last is a sentinel). The reason for placing
* the default last rather than first is that DES needs to be at the
* bottom for the algorithm guessing logic in crypt(3) to work correctly,
* and it needs to be the default for backward compatibility.
*/
static const struct crypt_format {
const char *name;
int (*func)(const char *, const char *, char *);
const char *magic;
} crypt_formats[] = {
{ "md5", crypt_md5, "$1$" },
#ifdef HAS_BLOWFISH
{ "blf", crypt_blowfish, "$2" },
#endif
{ "nth", crypt_nthash, "$3$" },
{ "sha256", crypt_sha256, "$5$" },
{ "sha512", crypt_sha512, "$6$" },
#ifdef HAS_DES
{ "des", crypt_des, "_" },
#endif
/* sentinel */
{ NULL, NULL, NULL }
};
static const struct crypt_format *crypt_format =
&crypt_formats[(sizeof crypt_formats / sizeof *crypt_formats) - 2];
#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_r(const char *passwd, const char *salt, struct crypt_data *data)
{
const struct crypt_format *cf;
int (*func)(const char *, const char *, char *);
#ifdef HAS_DES
int len;
#endif
for (cf = crypt_formats; cf->name != NULL; ++cf)
if (cf->magic != NULL && strstr(salt, cf->magic) == salt) {
func = cf->func;
goto match;
}
#ifdef HAS_DES
len = strlen(salt);
if ((len == 13 || len == 2) && strspn(salt, DES_SALT_ALPHABET) == len) {
func = crypt_des;
goto match;
}
#endif
func = crypt_format->func;
match:
if (func(passwd, salt, data->__buf) != 0)
return (NULL);
return (data->__buf);
}
char *
crypt(const char *passwd, const char *salt)
{
static struct crypt_data data;
return (crypt_r(passwd, salt, &data));
}