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MasterPassword/platform-independent/cli-c/cli/bcrypt.h

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/* $OpenBSD: bcrypt.c,v 1.57 2016/08/26 08:25:02 guenther Exp $ */
/*
* Copyright (c) 2014 Ted Unangst <tedu@openbsd.org>
* Copyright (c) 1997 Niels Provos <provos@umich.edu>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
/* 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);
*
*/
#include <sys/types.h>
#include <ctype.h>
#include <errno.h>
#include <pwd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
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#include "blf.h"
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#include "blowfish.h"
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/* 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_WORDS 6 /* Ciphertext words */
#define BCRYPT_MINLOGROUNDS 4 /* we have log2(rounds) in salt */
#define BCRYPT_SALTSPACE (7 + (BCRYPT_MAXSALT * 4 + 2) / 3 + 1)
#define BCRYPT_HASHSPACE 61
static int encode_base64(char *, const uint8_t *, size_t);
static int decode_base64(uint8_t *, size_t, const char *);
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/*
* Generates a salt for this version of crypt.
*/
static int
bcrypt_initsalt(int log_rounds, uint8_t *salt, size_t saltbuflen) {
uint8_t csalt[BCRYPT_MAXSALT];
if (saltbuflen < BCRYPT_SALTSPACE) {
errno = EINVAL;
return -1;
}
arc4random_buf( csalt, sizeof( csalt ) );
if (log_rounds < 4)
log_rounds = 4;
else if (log_rounds > 31)
log_rounds = 31;
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snprintf( (char *)salt, saltbuflen, "$2b$%2.2u$", log_rounds );
encode_base64( (char *)salt + 7, csalt, sizeof( csalt ) );
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return 0;
}
/*
* the core bcrypt function
*/
static int
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bcrypt_hashpass(const char *key, const uint8_t *salt, char *encrypted,
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size_t encryptedlen) {
blf_ctx state;
uint32_t rounds, i, k;
uint16_t j;
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size_t key_len;
uint8_t salt_len, logr, minor;
uint8_t ciphertext[4 * BCRYPT_WORDS] = "OrpheanBeholderScryDoubt";
uint8_t csalt[BCRYPT_MAXSALT];
uint32_t cdata[BCRYPT_WORDS];
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if (encryptedlen < BCRYPT_HASHSPACE)
goto inval;
/* Check and discard "$" identifier */
if (salt[0] != '$')
goto inval;
salt += 1;
if (salt[0] != BCRYPT_VERSION)
goto inval;
/* Check for minor versions */
switch ((minor = salt[1])) {
case 'a':
key_len = (uint8_t)(strlen( key ) + 1);
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break;
case 'b':
/* strlen() returns a size_t, but the function calls
* below result in implicit casts to a narrower integer
* type, so cap key_len at the actual maximum supported
* length here to avoid integer wraparound */
key_len = strlen( key );
if (key_len > 72)
key_len = 72;
key_len++; /* include the NUL */
break;
default:
goto inval;
}
if (salt[2] != '$')
goto inval;
/* Discard version + "$" identifier */
salt += 3;
/* Check and parse num rounds */
if (!isdigit( (unsigned char)salt[0] ) ||
!isdigit( (unsigned char)salt[1] ) || salt[2] != '$')
goto inval;
logr = (uint8_t)((salt[1] - '0') + ((salt[0] - '0') * 10));
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if (logr < BCRYPT_MINLOGROUNDS || logr > 31)
goto inval;
/* Computer power doesn't increase linearly, 2^x should be fine */
rounds = 1U << logr;
/* Discard num rounds + "$" identifier */
salt += 3;
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if (strlen( (char *)salt ) * 3 / 4 < BCRYPT_MAXSALT)
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goto inval;
/* We dont want the base64 salt but the raw data */
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if (decode_base64( csalt, BCRYPT_MAXSALT, (char *)salt ))
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goto inval;
salt_len = BCRYPT_MAXSALT;
/* Setting up S-Boxes and Subkeys */
Blowfish_initstate( &state );
Blowfish_expandstate( &state, csalt, salt_len,
(uint8_t *)key, (uint16_t)key_len );
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for (k = 0; k < rounds; k++) {
Blowfish_expand0state( &state, (uint8_t *)key, (uint16_t)key_len );
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Blowfish_expand0state( &state, csalt, salt_len );
}
/* This can be precomputed later */
j = 0;
for (i = 0; i < BCRYPT_WORDS; i++)
cdata[i] = Blowfish_stream2word( ciphertext, 4 * BCRYPT_WORDS, &j );
/* Now do the encryption */
for (k = 0; k < 64; k++)
blf_enc( &state, cdata, BCRYPT_WORDS / 2 );
for (i = 0; i < BCRYPT_WORDS; i++) {
ciphertext[4 * i + 3] = (uint8_t)(cdata[i] & 0xff);
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cdata[i] = cdata[i] >> 8;
ciphertext[4 * i + 2] = (uint8_t)(cdata[i] & 0xff);
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cdata[i] = cdata[i] >> 8;
ciphertext[4 * i + 1] = (uint8_t)(cdata[i] & 0xff);
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cdata[i] = cdata[i] >> 8;
ciphertext[4 * i + 0] = (uint8_t)(cdata[i] & 0xff);
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}
snprintf( encrypted, 8, "$2%c$%2.2u$", minor, logr );
encode_base64( encrypted + 7, csalt, BCRYPT_MAXSALT );
encode_base64( encrypted + 7 + 22, ciphertext, 4 * BCRYPT_WORDS - 1 );
bzero( &state, sizeof( state ) );
bzero( ciphertext, sizeof( ciphertext ) );
bzero( csalt, sizeof( csalt ) );
bzero( cdata, sizeof( cdata ) );
return 0;
inval:
errno = EINVAL;
return -1;
}
/*
* user friendly functions
*/
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static int
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bcrypt_newhash(const char *pass, int log_rounds, char *hash, size_t hashlen) {
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uint8_t salt[BCRYPT_SALTSPACE];
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if (bcrypt_initsalt( log_rounds, salt, sizeof( salt ) ) != 0)
return -1;
if (bcrypt_hashpass( pass, salt, hash, hashlen ) != 0)
return -1;
bzero( salt, sizeof( salt ) );
return 0;
}
static int __unused
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bcrypt_checkpass(const char *pass, const char *goodhash) {
char hash[BCRYPT_HASHSPACE];
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if (bcrypt_hashpass( pass, (const uint8_t *)goodhash, hash, sizeof( hash ) ) != 0)
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return -1;
if (strlen( hash ) != strlen( goodhash ) ||
timingsafe_bcmp( hash, goodhash, strlen( goodhash ) ) != 0) {
errno = EACCES;
return -1;
}
bzero( hash, sizeof( hash ) );
return 0;
}
/*
* Measure this system's performance by measuring the time for 8 rounds.
* We are aiming for something that takes around 0.1s, but not too much over.
*/
static int __unused
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_bcrypt_autorounds(void) {
struct timespec before, after;
int r = 8;
char buf[_PASSWORD_LEN];
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time_t duration;
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clock_gettime( CLOCK_THREAD_CPUTIME_ID, &before );
bcrypt_newhash( "testpassword", r, buf, sizeof( buf ) );
clock_gettime( CLOCK_THREAD_CPUTIME_ID, &after );
duration = after.tv_sec - before.tv_sec;
duration *= 1000000;
duration += (after.tv_nsec - before.tv_nsec) / 1000;
/* too quick? slow it down. */
while (r < 16 && duration <= 60000) {
r += 1;
duration *= 2;
}
/* too slow? speed it up. */
while (r > 6 && duration > 120000) {
r -= 1;
duration /= 2;
}
return r;
}
/*
* internal utilities
*/
static const uint8_t Base64Code[] =
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"./ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";
static const uint8_t index_64[128] = {
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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 ? (uint8_t)255 : index_64[(c)])
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/*
* read buflen (after decoding) bytes of data from b64data
*/
static int
decode_base64(uint8_t *buffer, size_t len, const char *b64data) {
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uint8_t *bp = buffer;
const uint8_t *p = (uint8_t *)b64data;
uint8_t c1, c2, c3, c4;
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while (bp < buffer + len) {
c1 = CHAR64( *p );
/* Invalid data */
if (c1 == 255)
return -1;
c2 = CHAR64( *(p + 1) );
if (c2 == 255)
return -1;
*bp++ = (uint8_t)((c1 << 2) | ((c2 & 0x30) >> 4));
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if (bp >= buffer + len)
break;
c3 = CHAR64( *(p + 2) );
if (c3 == 255)
return -1;
*bp++ = (uint8_t)(((c2 & 0x0f) << 4) | ((c3 & 0x3c) >> 2));
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if (bp >= buffer + len)
break;
c4 = CHAR64( *(p + 3) );
if (c4 == 255)
return -1;
*bp++ = (uint8_t)(((c3 & 0x03) << 6) | c4);
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p += 4;
}
return 0;
}
/*
* Turn len bytes of data into base64 encoded data.
* This works without = padding.
*/
static int
encode_base64(char *b64buffer, const uint8_t *data, size_t len) {
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uint8_t *bp = (uint8_t *)b64buffer;
const uint8_t *p = data;
uint8_t c1, c2;
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while (p < data + len) {
c1 = *p++;
*bp++ = Base64Code[(c1 >> 2)];
c1 = (uint8_t)((c1 & 0x03) << 4);
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if (p >= data + len) {
*bp++ = Base64Code[c1];
break;
}
c2 = *p++;
c1 |= (c2 >> 4) & 0x0f;
*bp++ = Base64Code[c1];
c1 = (uint8_t)((c2 & 0x0f) << 2);
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if (p >= data + len) {
*bp++ = Base64Code[c1];
break;
}
c2 = *p++;
c1 |= (c2 >> 6) & 0x03;
*bp++ = Base64Code[c1];
*bp++ = Base64Code[c2 & 0x3f];
}
*bp = '\0';
return 0;
}
/*
* classic interface
*/
static uint8_t *
bcrypt_gensalt(uint8_t log_rounds) {
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static uint8_t gsalt[BCRYPT_SALTSPACE];
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bcrypt_initsalt( log_rounds, gsalt, sizeof( gsalt ) );
return gsalt;
}
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static char *
bcrypt(const char *pass, const uint8_t *salt) {
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static char gencrypted[BCRYPT_HASHSPACE];
if (bcrypt_hashpass( pass, salt, gencrypted, sizeof( gencrypted ) ) != 0)
return NULL;
return gencrypted;
}