349 lines
9.0 KiB
C
349 lines
9.0 KiB
C
/*
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* Copyright 1997 Niels Provos <provos@physnet.uni-hamburg.de>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by Niels Provos.
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* 4. The name of the author may not be used to endorse or promote products
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* derived from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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/* This password hashing algorithm was designed by David Mazieres
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* <dm@lcs.mit.edu> and works as follows:
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*
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* 1. state := InitState ()
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* 2. state := ExpandKey (state, salt, password) 3.
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* REPEAT rounds:
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* state := ExpandKey (state, 0, salt)
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* state := ExpandKey(state, 0, password)
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* 4. ctext := "OrpheanBeholderScryDoubt"
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* 5. REPEAT 64:
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* ctext := Encrypt_ECB (state, ctext);
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* 6. RETURN Concatenate (salt, ctext);
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*
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*/
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/*
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* FreeBSD implementation by Paul Herman <pherman@frenchfries.net>
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <sys/types.h>
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#include <string.h>
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#include <pwd.h>
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#include "blowfish.h"
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#include "crypt.h"
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/* This implementation is adaptable to current computing power.
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* You can have up to 2^31 rounds which should be enough for some
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* time to come.
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*/
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#define BCRYPT_VERSION '2'
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#define BCRYPT_MAXSALT 16 /* Precomputation is just so nice */
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#define BCRYPT_BLOCKS 6 /* Ciphertext blocks */
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#define BCRYPT_MINROUNDS 16 /* we have log2(rounds) in salt */
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char *bcrypt_gensalt(u_int8_t);
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static void encode_salt(char *, u_int8_t *, u_int16_t, u_int8_t);
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static void encode_base64(u_int8_t *, u_int8_t *, u_int16_t);
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static void decode_base64(u_int8_t *, u_int16_t, const u_int8_t *);
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static char encrypted[_PASSWORD_LEN];
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static char gsalt[BCRYPT_MAXSALT * 4 / 3 + 1];
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static char error[] = ":";
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static const u_int8_t Base64Code[] =
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"./ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";
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static const u_int8_t index_64[128] =
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{
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255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
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255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
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255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
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255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
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255, 255, 255, 255, 255, 255, 0, 1, 54, 55,
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56, 57, 58, 59, 60, 61, 62, 63, 255, 255,
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255, 255, 255, 255, 255, 2, 3, 4, 5, 6,
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7, 8, 9, 10, 11, 12, 13, 14, 15, 16,
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17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27,
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255, 255, 255, 255, 255, 255, 28, 29, 30,
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31, 32, 33, 34, 35, 36, 37, 38, 39, 40,
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41, 42, 43, 44, 45, 46, 47, 48, 49, 50,
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51, 52, 53, 255, 255, 255, 255, 255
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};
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#define CHAR64(c) ( (c) > 127 ? 255 : index_64[(c)])
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static void
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decode_base64(u_int8_t *buffer, u_int16_t len, const u_int8_t *data)
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{
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u_int8_t *bp = buffer;
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const u_int8_t *p = data;
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u_int8_t c1, c2, c3, c4;
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while (bp < buffer + len) {
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c1 = CHAR64(*p);
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c2 = CHAR64(*(p + 1));
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/* Invalid data */
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if (c1 == 255 || c2 == 255)
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break;
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*bp++ = (u_int8_t)((c1 << 2) | ((c2 & 0x30) >> 4));
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if (bp >= buffer + len)
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break;
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c3 = CHAR64(*(p + 2));
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if (c3 == 255)
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break;
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*bp++ = ((c2 & 0x0f) << 4) | ((c3 & 0x3c) >> 2);
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if (bp >= buffer + len)
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break;
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c4 = CHAR64(*(p + 3));
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if (c4 == 255)
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break;
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*bp++ = ((c3 & 0x03) << 6) | c4;
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p += 4;
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}
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}
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static void
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encode_salt(char *salt, u_int8_t *csalt, u_int16_t clen, u_int8_t logr)
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{
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salt[0] = '$';
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salt[1] = BCRYPT_VERSION;
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salt[2] = 'a';
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salt[3] = '$';
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snprintf(salt + 4, 4, "%2.2u$", logr);
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encode_base64((u_int8_t *) salt + 7, csalt, clen);
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}
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/* Generates a salt for this version of crypt.
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Since versions may change. Keeping this here
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seems sensible.
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*/
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char *
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bcrypt_gensalt(u_int8_t log_rounds)
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{
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u_int8_t csalt[BCRYPT_MAXSALT];
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u_int16_t i;
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u_int32_t seed = 0;
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for (i = 0; i < BCRYPT_MAXSALT; i++) {
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if (i % 4 == 0)
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seed = arc4random();
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csalt[i] = seed & 0xff;
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seed = seed >> 8;
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}
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if (log_rounds < 4)
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log_rounds = 4;
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encode_salt(gsalt, csalt, BCRYPT_MAXSALT, log_rounds);
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return gsalt;
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}
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/* We handle $Vers$log2(NumRounds)$salt+passwd$
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i.e. $2$04$iwouldntknowwhattosayetKdJ6iFtacBqJdKe6aW7ou */
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char *
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crypt_blowfish(const char *key, const char *salt)
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{
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blf_ctx state;
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u_int32_t rounds, i, k;
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u_int16_t j;
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u_int8_t key_len, salt_len, logr, minr;
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u_int8_t ciphertext[4 * BCRYPT_BLOCKS] = "OrpheanBeholderScryDoubt";
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u_int8_t csalt[BCRYPT_MAXSALT];
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u_int32_t cdata[BCRYPT_BLOCKS];
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static const char *magic = "$2a$04$";
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/* Defaults */
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minr = 'a';
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logr = 4;
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rounds = 1 << logr;
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/* If it starts with the magic string, then skip that */
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if(!strncmp(salt, magic, strlen(magic))) {
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salt += strlen(magic);
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}
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else if (*salt == '$') {
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/* Discard "$" identifier */
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salt++;
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if (*salt > BCRYPT_VERSION) {
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/* How do I handle errors ? Return ':' */
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return error;
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}
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/* Check for minor versions */
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if (salt[1] != '$') {
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switch (salt[1]) {
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case 'a':
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/* 'ab' should not yield the same as 'abab' */
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minr = (u_int8_t)salt[1];
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salt++;
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break;
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default:
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return error;
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}
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} else
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minr = 0;
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/* Discard version + "$" identifier */
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salt += 2;
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if (salt[2] != '$')
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/* Out of sync with passwd entry */
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return error;
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/* Computer power doesnt increase linear, 2^x should be fine */
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logr = (u_int8_t)atoi(salt);
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rounds = 1 << logr;
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if (rounds < BCRYPT_MINROUNDS)
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return error;
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/* Discard num rounds + "$" identifier */
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salt += 3;
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}
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/* We dont want the base64 salt but the raw data */
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decode_base64(csalt, BCRYPT_MAXSALT, salt);
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salt_len = BCRYPT_MAXSALT;
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key_len = (u_int8_t)(strlen(key) + (minr >= 'a' ? 1 : 0));
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/* Setting up S-Boxes and Subkeys */
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Blowfish_initstate(&state);
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Blowfish_expandstate(&state, csalt, salt_len,
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(const u_int8_t *) key, key_len);
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for (k = 0; k < rounds; k++) {
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Blowfish_expand0state(&state, (const u_int8_t *) key, key_len);
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Blowfish_expand0state(&state, csalt, salt_len);
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}
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/* This can be precomputed later */
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j = 0;
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for (i = 0; i < BCRYPT_BLOCKS; i++)
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cdata[i] = Blowfish_stream2word(ciphertext, 4 * BCRYPT_BLOCKS, &j);
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/* Now do the encryption */
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for (k = 0; k < 64; k++)
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blf_enc(&state, cdata, BCRYPT_BLOCKS / 2);
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for (i = 0; i < BCRYPT_BLOCKS; i++) {
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ciphertext[4 * i + 3] = cdata[i] & 0xff;
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cdata[i] = cdata[i] >> 8;
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ciphertext[4 * i + 2] = cdata[i] & 0xff;
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cdata[i] = cdata[i] >> 8;
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ciphertext[4 * i + 1] = cdata[i] & 0xff;
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cdata[i] = cdata[i] >> 8;
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ciphertext[4 * i + 0] = cdata[i] & 0xff;
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}
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i = 0;
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encrypted[i++] = '$';
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encrypted[i++] = BCRYPT_VERSION;
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if (minr)
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encrypted[i++] = (int8_t)minr;
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encrypted[i++] = '$';
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snprintf(encrypted + i, 4, "%2.2u$", logr);
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encode_base64((u_int8_t *) encrypted + i + 3, csalt, BCRYPT_MAXSALT);
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encode_base64((u_int8_t *) encrypted + strlen(encrypted), ciphertext,
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4 * BCRYPT_BLOCKS - 1);
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return encrypted;
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}
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static void
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encode_base64(u_int8_t *buffer, u_int8_t *data, u_int16_t len)
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{
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u_int8_t *bp = buffer;
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u_int8_t *p = data;
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u_int8_t c1, c2;
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while (p < data + len) {
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c1 = *p++;
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*bp++ = Base64Code[(c1 >> 2)];
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c1 = (c1 & 0x03) << 4;
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if (p >= data + len) {
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*bp++ = Base64Code[c1];
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break;
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}
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c2 = *p++;
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c1 |= (c2 >> 4) & 0x0f;
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*bp++ = Base64Code[c1];
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c1 = (c2 & 0x0f) << 2;
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if (p >= data + len) {
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*bp++ = Base64Code[c1];
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break;
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}
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c2 = *p++;
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c1 |= (c2 >> 6) & 0x03;
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*bp++ = Base64Code[c1];
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*bp++ = Base64Code[c2 & 0x3f];
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}
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*bp = '\0';
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}
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#if 0
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void
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main()
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{
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char blubber[73];
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char salt[100];
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char *p;
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salt[0] = '$';
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salt[1] = BCRYPT_VERSION;
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salt[2] = '$';
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snprintf(salt + 3, 4, "%2.2u$", 5);
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printf("24 bytes of salt: ");
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fgets(salt + 6, 94, stdin);
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salt[99] = 0;
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printf("72 bytes of password: ");
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fpurge(stdin);
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fgets(blubber, 73, stdin);
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blubber[72] = 0;
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p = crypt(blubber, salt);
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printf("Passwd entry: %s\n\n", p);
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p = bcrypt_gensalt(5);
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printf("Generated salt: %s\n", p);
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p = crypt(blubber, p);
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printf("Passwd entry: %s\n", p);
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}
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#endif
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