/* $OpenBSD: bcrypt.c,v 1.29 2014/02/24 19:45:43 tedu 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.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
/* 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, password)
* state := ExpandKey (state, 0, salt)
* 4. ctext := "OrpheanBeholderScryDoubt"
* 5. REPEAT 64:
* ctext := Encrypt_ECB (state, ctext);
* 6. RETURN Concatenate (salt, ctext);
*
*/
/*
* FreeBSD implementation by Paul Herman <pherman@frenchfries.net>
* and updated by Xin Li <delphij@FreeBSD.org>
*/
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <string.h>
#include <pwd.h>
#include "blowfish.h"
#include "crypt.h"
/* 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_BLOCKS 6 /* Ciphertext blocks */
#define BCRYPT_MINLOGROUNDS 4 /* we have log2(rounds) in salt */
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 *);
const static u_int8_t Base64Code[] =
"./ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";
const static 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++ = (c1 << 2) | ((c2 & 0x30) >> 4);
if (bp >= buffer + len)
break;
c3 = CHAR64(*(p + 2));
if (c3 == 255)
break;
*bp++ = ((c2 & 0x0f) << 4) | ((c3 & 0x3c) >> 2);
if (bp >= buffer + len)
break;
c4 = CHAR64(*(p + 3));
if (c4 == 255)
break;
*bp++ = ((c3 & 0x03) << 6) | c4;
p += 4;
}
}
/* We handle $Vers$log2(NumRounds)$salt+passwd$
i.e. $2$04$iwouldntknowwhattosayetKdJ6iFtacBqJdKe6aW7ou */
int
crypt_blowfish(const char *key, const char *salt, char *buffer)
{
blf_ctx state;
u_int32_t rounds, i, k;
u_int16_t j;
size_t key_len;
u_int8_t salt_len, logr, minr;
u_int8_t ciphertext[4 * BCRYPT_BLOCKS] = "OrpheanBeholderScryDoubt";
u_int8_t csalt[BCRYPT_MAXSALT];
u_int32_t cdata[BCRYPT_BLOCKS];
char arounds[3];
/* Defaults */
minr = 'b';
logr = BCRYPT_MINLOGROUNDS;
rounds = 1U << logr;
if (*salt == '$') {
/* Discard "$" identifier */
salt++;
if (*salt > BCRYPT_VERSION)
return (-1);
/* Check for minor versions */
if (salt[1] != '$') {
switch (salt[1]) {
case 'a': /* 'ab' should not yield the same as 'abab' */
case 'b': /* cap input length at 72 bytes */
case 'y': /* same as 'b', for compatibility
* with openwall crypt_blowfish
*/
minr = salt[1];
salt++;
break;
default:
return (-1);
}
} else
minr = 0;
/* Discard version + "$" identifier */
salt += 2;
if (salt[2] != '$')
/* Out of sync with passwd entry */
return (-1);
memcpy(arounds, salt, sizeof(arounds));
if (arounds[sizeof(arounds) - 1] != '$')
return (-1);
arounds[sizeof(arounds) - 1] = 0;
logr = strtonum(arounds, BCRYPT_MINLOGROUNDS, 31, NULL);
if (logr == 0)
return (-1);
/* Computer power doesn't increase linearly, 2^x should be fine */
rounds = 1U << logr;
/* Discard num rounds + "$" identifier */
salt += 3;
}
if (strlen(salt) * 3 / 4 < BCRYPT_MAXSALT)
return (-1);
/* We dont want the base64 salt but the raw data */
decode_base64(csalt, BCRYPT_MAXSALT, (const u_int8_t *) salt);
salt_len = BCRYPT_MAXSALT;
if (minr <= 'a')
key_len = (u_int8_t)(strlen(key) + (minr >= 'a' ? 1 : 0));
else {
/* strlen() returns a size_t, but the function calls
* below result in implicit casts to a narrower integer
* type, so cap key_len at the actual maximum supported
* length here to avoid integer wraparound */
key_len = strlen(key);
if (key_len > 72)
key_len = 72;
key_len++; /* include the NUL */
}
/* Setting up S-Boxes and Subkeys */
Blowfish_initstate(&state);
Blowfish_expandstate(&state, csalt, salt_len,
(const u_int8_t *) key, key_len);
for (k = 0; k < rounds; k++) {
Blowfish_expand0state(&state, (const u_int8_t *) key, key_len);
Blowfish_expand0state(&state, csalt, salt_len);
}
/* This can be precomputed later */
j = 0;
for (i = 0; i < BCRYPT_BLOCKS; i++)
cdata[i] = Blowfish_stream2word(ciphertext, 4 * BCRYPT_BLOCKS, &j);
/* Now do the encryption */
for (k = 0; k < 64; k++)
blf_enc(&state, cdata, BCRYPT_BLOCKS / 2);
for (i = 0; i < BCRYPT_BLOCKS; i++) {
ciphertext[4 * i + 3] = cdata[i] & 0xff;
cdata[i] = cdata[i] >> 8;
ciphertext[4 * i + 2] = cdata[i] & 0xff;
cdata[i] = cdata[i] >> 8;
ciphertext[4 * i + 1] = cdata[i] & 0xff;
cdata[i] = cdata[i] >> 8;
ciphertext[4 * i + 0] = cdata[i] & 0xff;
}
*buffer++ = '$';
*buffer++ = BCRYPT_VERSION;
if (minr)
*buffer++ = minr;
*buffer++ = '$';
snprintf(buffer, 4, "%2.2u$", logr);
buffer += 3;
encode_base64((u_int8_t *)buffer, csalt, BCRYPT_MAXSALT);
buffer += strlen(buffer);
encode_base64((u_int8_t *)buffer, ciphertext, 4 * BCRYPT_BLOCKS - 1);
memset(&state, 0, sizeof(state));
memset(ciphertext, 0, sizeof(ciphertext));
memset(csalt, 0, sizeof(csalt));
memset(cdata, 0, sizeof(cdata));
return (0);
}
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[(c1 >> 2)];
c1 = (c1 & 0x03) << 4;
if (p >= data + len) {
*bp++ = Base64Code[c1];
break;
}
c2 = *p++;
c1 |= (c2 >> 4) & 0x0f;
*bp++ = Base64Code[c1];
c1 = (c2 & 0x0f) << 2;
if (p >= data + len) {
*bp++ = Base64Code[c1];
break;
}
c2 = *p++;
c1 |= (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, sizeof(salt) - 6, stdin);
salt[99] = 0;
printf("72 bytes of password: ");
fpurge(stdin);
fgets(blubber, sizeof(blubber), 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