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freebsd/lib/libcrypt/crypt-md5.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

148 lines
4.4 KiB
C

/*-
* Copyright (c) 2003 Poul-Henning Kamp
* 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 THE AUTHOR 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 AUTHOR 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 <err.h>
#include <md5.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include "crypt.h"
/*
* UNIX password
*/
int
crypt_md5(const char *pw, const char *salt, char *buffer)
{
MD5_CTX ctx,ctx1;
unsigned long l;
int sl, pl;
u_int i;
u_char final[MD5_SIZE];
const char *ep;
static const char *magic = "$1$";
/* If the salt starts with the magic string, skip that. */
if (!strncmp(salt, magic, strlen(magic)))
salt += strlen(magic);
/* It stops at the first '$', max 8 chars */
for (ep = salt; *ep && *ep != '$' && ep < salt + 8; ep++)
continue;
/* get the length of the true salt */
sl = ep - salt;
MD5Init(&ctx);
/* The password first, since that is what is most unknown */
MD5Update(&ctx, (const u_char *)pw, strlen(pw));
/* Then our magic string */
MD5Update(&ctx, (const u_char *)magic, strlen(magic));
/* Then the raw salt */
MD5Update(&ctx, (const u_char *)salt, (u_int)sl);
/* Then just as many characters of the MD5(pw,salt,pw) */
MD5Init(&ctx1);
MD5Update(&ctx1, (const u_char *)pw, strlen(pw));
MD5Update(&ctx1, (const u_char *)salt, (u_int)sl);
MD5Update(&ctx1, (const u_char *)pw, strlen(pw));
MD5Final(final, &ctx1);
for(pl = (int)strlen(pw); pl > 0; pl -= MD5_SIZE)
MD5Update(&ctx, (const u_char *)final,
(u_int)(pl > MD5_SIZE ? MD5_SIZE : pl));
/* Don't leave anything around in vm they could use. */
memset(final, 0, sizeof(final));
/* Then something really weird... */
for (i = strlen(pw); i; i >>= 1)
if(i & 1)
MD5Update(&ctx, (const u_char *)final, 1);
else
MD5Update(&ctx, (const u_char *)pw, 1);
/* Now make the output string */
buffer = stpcpy(buffer, magic);
buffer = stpncpy(buffer, salt, (u_int)sl);
*buffer++ = '$';
MD5Final(final, &ctx);
/*
* and now, just to make sure things don't run too fast
* On a 60 Mhz Pentium this takes 34 msec, so you would
* need 30 seconds to build a 1000 entry dictionary...
*/
for(i = 0; i < 1000; i++) {
MD5Init(&ctx1);
if(i & 1)
MD5Update(&ctx1, (const u_char *)pw, strlen(pw));
else
MD5Update(&ctx1, (const u_char *)final, MD5_SIZE);
if(i % 3)
MD5Update(&ctx1, (const u_char *)salt, (u_int)sl);
if(i % 7)
MD5Update(&ctx1, (const u_char *)pw, strlen(pw));
if(i & 1)
MD5Update(&ctx1, (const u_char *)final, MD5_SIZE);
else
MD5Update(&ctx1, (const u_char *)pw, strlen(pw));
MD5Final(final, &ctx1);
}
l = (final[ 0]<<16) | (final[ 6]<<8) | final[12];
_crypt_to64(buffer, l, 4); buffer += 4;
l = (final[ 1]<<16) | (final[ 7]<<8) | final[13];
_crypt_to64(buffer, l, 4); buffer += 4;
l = (final[ 2]<<16) | (final[ 8]<<8) | final[14];
_crypt_to64(buffer, l, 4); buffer += 4;
l = (final[ 3]<<16) | (final[ 9]<<8) | final[15];
_crypt_to64(buffer, l, 4); buffer += 4;
l = (final[ 4]<<16) | (final[10]<<8) | final[ 5];
_crypt_to64(buffer, l, 4); buffer += 4;
l = final[11];
_crypt_to64(buffer, l, 2); buffer += 2;
*buffer = '\0';
/* Don't leave anything around in vm they could use. */
memset(final, 0, sizeof(final));
return (0);
}