NetBSD/lib/libcrypt/bcrypt.c

380 lines
9.8 KiB
C

/* $NetBSD: bcrypt.c,v 1.19 2013/08/28 17:47:07 riastradh Exp $ */
/* $OpenBSD: bcrypt.c,v 1.16 2002/02/19 19:39:36 millert Exp $ */
/*
* Copyright 1997 Niels Provos <provos@physnet.uni-hamburg.de>
* 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.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by Niels Provos.
* 4. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 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.
*/
/* This password hashing algorithm was designed by David Mazieres
* <dm@lcs.mit.edu> and works as follows:
*
* 1. state := InitState ()
* 2. state := ExpandKey (state, salt, password) 3.
* REPEAT rounds:
* state := ExpandKey (state, 0, salt)
* state := ExpandKey(state, 0, password)
* 4. ctext := "OrpheanBeholderScryDoubt"
* 5. REPEAT 64:
* ctext := Encrypt_ECB (state, ctext);
* 6. RETURN Concatenate (salt, ctext);
*
*/
#include <sys/cdefs.h>
__RCSID("$NetBSD: bcrypt.c,v 1.19 2013/08/28 17:47:07 riastradh Exp $");
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <string.h>
#include <pwd.h>
#include <errno.h>
#include <limits.h>
#include "crypt.h"
#include "blowfish.c"
/* This implementation is adaptable to current computing power.
* You can have up to 2^31 rounds which should be enough for some
* time to come.
*/
#define BCRYPT_VERSION '2'
#define BCRYPT_MAXSALT 16 /* Precomputation is just so nice */
#define BCRYPT_MAXSALTLEN (7 + (BCRYPT_MAXSALT * 4 + 2) / 3 + 1)
#define BCRYPT_BLOCKS 6 /* Ciphertext blocks */
#define BCRYPT_MINROUNDS 16 /* we have log2(rounds) in salt */
static void encode_salt(char *, u_int8_t *, u_int16_t, u_int8_t);
static void encode_base64(u_int8_t *, u_int8_t *, u_int16_t);
static void decode_base64(u_int8_t *, u_int16_t, const u_int8_t *);
char *__bcrypt(const char *, const char *); /* XXX */
static char encrypted[_PASSWORD_LEN];
static const u_int8_t Base64Code[] =
"./ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";
char *bcrypt_gensalt(u_int8_t);
static const u_int8_t index_64[128] =
{
255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 0, 1, 54, 55,
56, 57, 58, 59, 60, 61, 62, 63, 255, 255,
255, 255, 255, 255, 255, 2, 3, 4, 5, 6,
7, 8, 9, 10, 11, 12, 13, 14, 15, 16,
17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27,
255, 255, 255, 255, 255, 255, 28, 29, 30,
31, 32, 33, 34, 35, 36, 37, 38, 39, 40,
41, 42, 43, 44, 45, 46, 47, 48, 49, 50,
51, 52, 53, 255, 255, 255, 255, 255
};
#define CHAR64(c) ( (c) > 127 ? 255 : index_64[(c)])
static void
decode_base64(u_int8_t *buffer, u_int16_t len, const u_int8_t *data)
{
u_int8_t *bp = buffer;
const u_int8_t *p = data;
u_int8_t c1, c2, c3, c4;
while (bp < buffer + len) {
c1 = CHAR64(*p);
c2 = CHAR64(*(p + 1));
/* Invalid data */
if (c1 == 255 || c2 == 255)
break;
*bp++ = ((u_int32_t)c1 << 2) | (((u_int32_t)c2 & 0x30) >> 4);
if (bp >= buffer + len)
break;
c3 = CHAR64(*(p + 2));
if (c3 == 255)
break;
*bp++ = (((u_int32_t)c2 & 0x0f) << 4) | (((uint32_t)c3 & 0x3c) >> 2);
if (bp >= buffer + len)
break;
c4 = CHAR64(*(p + 3));
if (c4 == 255)
break;
*bp++ = ((c3 & 0x03) << 6) | c4;
p += 4;
}
}
static void
encode_salt(char *salt, u_int8_t *csalt, u_int16_t clen, u_int8_t logr)
{
salt[0] = '$';
salt[1] = BCRYPT_VERSION;
salt[2] = 'a';
salt[3] = '$';
snprintf(salt + 4, 4, "%2.2u$", logr);
encode_base64((u_int8_t *) salt + 7, csalt, clen);
}
int
__gensalt_blowfish(char *salt, size_t saltlen, const char *option)
{
size_t i;
u_int32_t seed = 0;
u_int8_t csalt[BCRYPT_MAXSALT];
unsigned long nrounds;
char *ep;
if (saltlen < BCRYPT_MAXSALTLEN) {
errno = ENOSPC;
return -1;
}
if (option == NULL) {
errno = EINVAL;
return -1;
}
nrounds = strtoul(option, &ep, 0);
if (option == ep || *ep) {
errno = EINVAL;
return -1;
}
if (errno == ERANGE && nrounds == ULONG_MAX)
return -1;
if (nrounds < 4)
nrounds = 4;
else if (nrounds > 31)
nrounds = 31;
for (i = 0; i < BCRYPT_MAXSALT; i++) {
if (i % 4 == 0)
seed = arc4random();
csalt[i] = seed & 0xff;
seed = seed >> 8;
}
encode_salt(salt, csalt, BCRYPT_MAXSALT, (u_int8_t)nrounds);
return 0;
}
/* Generates a salt for this version of crypt.
Since versions may change. Keeping this here
seems sensible.
XXX: compat.
*/
char *
bcrypt_gensalt(u_int8_t log_rounds)
{
static char gsalt[BCRYPT_MAXSALTLEN];
char num[10];
(void)snprintf(num, sizeof(num), "%d", log_rounds);
if (__gensalt_blowfish(gsalt, sizeof(gsalt), num) == -1)
return NULL;
return gsalt;
}
/* We handle $Vers$log2(NumRounds)$salt+passwd$
i.e. $2$04$iwouldntknowwhattosayetKdJ6iFtacBqJdKe6aW7ou */
char *
__bcrypt(const char *key, const char *salt)
{
blf_ctx state;
u_int32_t rounds, i, k;
u_int16_t j;
u_int8_t key_len, salt_len, logr, minor;
u_int8_t ciphertext[4 * BCRYPT_BLOCKS] = "OrpheanBeholderScryDoubt";
u_int8_t csalt[BCRYPT_MAXSALT];
u_int32_t cdata[BCRYPT_BLOCKS];
int n;
size_t len;
/* Discard "$" identifier */
salt++;
if (*salt > BCRYPT_VERSION)
return NULL;
/* Check for minor versions */
if (salt[1] != '$') {
switch (salt[1]) {
case 'a':
/* 'ab' should not yield the same as 'abab' */
minor = salt[1];
salt++;
break;
default:
return NULL;
}
} else
minor = 0;
/* Discard version + "$" identifier */
salt += 2;
if (salt[2] != '$')
/* Out of sync with passwd entry */
return NULL;
/* Computer power doesn't increase linear, 2^x should be fine */
n = atoi(salt);
if (n > 31 || n < 0)
return NULL;
logr = (u_int8_t)n;
if ((rounds = (u_int32_t) 1 << logr) < BCRYPT_MINROUNDS)
return NULL;
/* Discard num rounds + "$" identifier */
salt += 3;
if (strlen(salt) * 3 / 4 < BCRYPT_MAXSALT)
return NULL;
/* We dont want the base64 salt but the raw data */
decode_base64(csalt, BCRYPT_MAXSALT, (const u_int8_t *)salt);
salt_len = BCRYPT_MAXSALT;
len = strlen(key);
if (len > 72)
key_len = 72;
else
key_len = (uint8_t)len;
key_len += minor >= 'a' ? 1 : 0;
/* Setting up S-Boxes and Subkeys */
Blowfish_initstate(&state);
Blowfish_expandstate(&state, csalt, salt_len,
(const u_int8_t *) key, key_len);
for (k = 0; k < rounds; k++) {
Blowfish_expand0state(&state, (const u_int8_t *) key, key_len);
Blowfish_expand0state(&state, csalt, salt_len);
}
/* This can be precomputed later */
j = 0;
for (i = 0; i < BCRYPT_BLOCKS; i++)
cdata[i] = Blowfish_stream2word(ciphertext, 4 * BCRYPT_BLOCKS, &j);
/* Now do the encryption */
for (k = 0; k < 64; k++)
blf_enc(&state, cdata, BCRYPT_BLOCKS / 2);
for (i = 0; i < BCRYPT_BLOCKS; i++) {
ciphertext[4 * i + 3] = cdata[i] & 0xff;
cdata[i] = cdata[i] >> 8;
ciphertext[4 * i + 2] = cdata[i] & 0xff;
cdata[i] = cdata[i] >> 8;
ciphertext[4 * i + 1] = cdata[i] & 0xff;
cdata[i] = cdata[i] >> 8;
ciphertext[4 * i + 0] = cdata[i] & 0xff;
}
i = 0;
encrypted[i++] = '$';
encrypted[i++] = BCRYPT_VERSION;
if (minor)
encrypted[i++] = minor;
encrypted[i++] = '$';
snprintf(encrypted + i, 4, "%2.2u$", logr);
encode_base64((u_int8_t *) encrypted + i + 3, csalt, BCRYPT_MAXSALT);
encode_base64((u_int8_t *) encrypted + strlen(encrypted), ciphertext,
4 * BCRYPT_BLOCKS - 1);
explicit_memset(&state, 0, sizeof(state));
return encrypted;
}
static void
encode_base64(u_int8_t *buffer, u_int8_t *data, u_int16_t len)
{
u_int8_t *bp = buffer;
u_int8_t *p = data;
u_int8_t c1, c2;
while (p < data + len) {
c1 = *p++;
*bp++ = Base64Code[((u_int32_t)c1 >> 2)];
c1 = (c1 & 0x03) << 4;
if (p >= data + len) {
*bp++ = Base64Code[c1];
break;
}
c2 = *p++;
c1 |= ((u_int32_t)c2 >> 4) & 0x0f;
*bp++ = Base64Code[c1];
c1 = (c2 & 0x0f) << 2;
if (p >= data + len) {
*bp++ = Base64Code[c1];
break;
}
c2 = *p++;
c1 |= ((u_int32_t)c2 >> 6) & 0x03;
*bp++ = Base64Code[c1];
*bp++ = Base64Code[c2 & 0x3f];
}
*bp = '\0';
}
#if 0
void
main()
{
char blubber[73];
char salt[100];
char *p;
salt[0] = '$';
salt[1] = BCRYPT_VERSION;
salt[2] = '$';
snprintf(salt + 3, 4, "%2.2u$", 5);
printf("24 bytes of salt: ");
fgets(salt + 6, 94, stdin);
salt[99] = 0;
printf("72 bytes of password: ");
fpurge(stdin);
fgets(blubber, 73, stdin);
blubber[72] = 0;
p = crypt(blubber, salt);
printf("Passwd entry: %s\n\n", p);
p = bcrypt_gensalt(5);
printf("Generated salt: %s\n", p);
p = crypt(blubber, p);
printf("Passwd entry: %s\n", p);
}
#endif