1 /* $OpenBSD: bcrypt.c,v 1.29 2014/02/24 19:45:43 tedu Exp $ */ 2 3 /* 4 * Copyright 1997 Niels Provos <provos@physnet.uni-hamburg.de> 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. All advertising materials mentioning features or use of this software 16 * must display the following acknowledgement: 17 * This product includes software developed by Niels Provos. 18 * 4. The name of the author may not be used to endorse or promote products 19 * derived from this software without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 22 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 23 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 24 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 25 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 26 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 27 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 28 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 29 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 30 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 31 */ 32 33 #include <sys/cdefs.h> 34 __FBSDID("$FreeBSD$"); 35 36 /* This password hashing algorithm was designed by David Mazieres 37 * <dm@lcs.mit.edu> and works as follows: 38 * 39 * 1. state := InitState () 40 * 2. state := ExpandKey (state, salt, password) 41 * 3. REPEAT rounds: 42 * state := ExpandKey (state, 0, password) 43 * state := ExpandKey (state, 0, salt) 44 * 4. ctext := "OrpheanBeholderScryDoubt" 45 * 5. REPEAT 64: 46 * ctext := Encrypt_ECB (state, ctext); 47 * 6. RETURN Concatenate (salt, ctext); 48 * 49 */ 50 51 /* 52 * FreeBSD implementation by Paul Herman <pherman@frenchfries.net> 53 * and updated by Xin Li <delphij@FreeBSD.org> 54 */ 55 56 #include <stdio.h> 57 #include <stdlib.h> 58 #include <sys/types.h> 59 #include <string.h> 60 #include <pwd.h> 61 #include "blowfish.h" 62 #include "crypt.h" 63 64 /* This implementation is adaptable to current computing power. 65 * You can have up to 2^31 rounds which should be enough for some 66 * time to come. 67 */ 68 69 #define BCRYPT_VERSION '2' 70 #define BCRYPT_MAXSALT 16 /* Precomputation is just so nice */ 71 #define BCRYPT_BLOCKS 6 /* Ciphertext blocks */ 72 #define BCRYPT_MINLOGROUNDS 4 /* we have log2(rounds) in salt */ 73 74 75 static void encode_base64(u_int8_t *, u_int8_t *, u_int16_t); 76 static void decode_base64(u_int8_t *, u_int16_t, const u_int8_t *); 77 78 static char encrypted[_PASSWORD_LEN]; 79 80 const static u_int8_t Base64Code[] = 81 "./ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"; 82 83 const static u_int8_t index_64[128] = { 84 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 85 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 86 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 87 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 88 255, 255, 255, 255, 255, 255, 0, 1, 54, 55, 89 56, 57, 58, 59, 60, 61, 62, 63, 255, 255, 90 255, 255, 255, 255, 255, 2, 3, 4, 5, 6, 91 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 92 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 93 255, 255, 255, 255, 255, 255, 28, 29, 30, 94 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 95 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 96 51, 52, 53, 255, 255, 255, 255, 255 97 }; 98 #define CHAR64(c) ( (c) > 127 ? 255 : index_64[(c)]) 99 100 static void 101 decode_base64(u_int8_t *buffer, u_int16_t len, const u_int8_t *data) 102 { 103 u_int8_t *bp = buffer; 104 const u_int8_t *p = data; 105 u_int8_t c1, c2, c3, c4; 106 while (bp < buffer + len) { 107 c1 = CHAR64(*p); 108 c2 = CHAR64(*(p + 1)); 109 110 /* Invalid data */ 111 if (c1 == 255 || c2 == 255) 112 break; 113 114 *bp++ = (c1 << 2) | ((c2 & 0x30) >> 4); 115 if (bp >= buffer + len) 116 break; 117 118 c3 = CHAR64(*(p + 2)); 119 if (c3 == 255) 120 break; 121 122 *bp++ = ((c2 & 0x0f) << 4) | ((c3 & 0x3c) >> 2); 123 if (bp >= buffer + len) 124 break; 125 126 c4 = CHAR64(*(p + 3)); 127 if (c4 == 255) 128 break; 129 *bp++ = ((c3 & 0x03) << 6) | c4; 130 131 p += 4; 132 } 133 } 134 135 /* We handle $Vers$log2(NumRounds)$salt+passwd$ 136 i.e. $2$04$iwouldntknowwhattosayetKdJ6iFtacBqJdKe6aW7ou */ 137 138 char * 139 crypt_blowfish(const char *key, const char *salt) 140 { 141 blf_ctx state; 142 u_int32_t rounds, i, k; 143 u_int16_t j; 144 size_t key_len; 145 u_int8_t salt_len, logr, minr; 146 u_int8_t ciphertext[4 * BCRYPT_BLOCKS] = "OrpheanBeholderScryDoubt"; 147 u_int8_t csalt[BCRYPT_MAXSALT]; 148 u_int32_t cdata[BCRYPT_BLOCKS]; 149 char arounds[3]; 150 151 /* Defaults */ 152 minr = 'b'; 153 logr = BCRYPT_MINLOGROUNDS; 154 rounds = 1U << logr; 155 156 if (*salt == '$') { 157 /* Discard "$" identifier */ 158 salt++; 159 160 if (*salt > BCRYPT_VERSION) { 161 /* How do I handle errors ? Return NULL */ 162 return NULL; 163 } 164 165 /* Check for minor versions */ 166 if (salt[1] != '$') { 167 switch (salt[1]) { 168 case 'a': /* 'ab' should not yield the same as 'abab' */ 169 case 'b': /* cap input length at 72 bytes */ 170 case 'y': /* same as 'b', for compatibility 171 * with openwall crypt_blowfish 172 */ 173 minr = salt[1]; 174 salt++; 175 break; 176 default: 177 return NULL; 178 } 179 } else 180 minr = 0; 181 182 /* Discard version + "$" identifier */ 183 salt += 2; 184 185 if (salt[2] != '$') 186 /* Out of sync with passwd entry */ 187 return NULL; 188 189 memcpy(arounds, salt, sizeof(arounds)); 190 if (arounds[sizeof(arounds) - 1] != '$') 191 return NULL; 192 arounds[sizeof(arounds) - 1] = 0; 193 logr = strtonum(arounds, BCRYPT_MINLOGROUNDS, 31, NULL); 194 if (logr == 0) 195 return NULL; 196 /* Computer power doesn't increase linearly, 2^x should be fine */ 197 rounds = 1U << logr; 198 199 /* Discard num rounds + "$" identifier */ 200 salt += 3; 201 } 202 203 if (strlen(salt) * 3 / 4 < BCRYPT_MAXSALT) 204 return NULL; 205 206 /* We dont want the base64 salt but the raw data */ 207 decode_base64(csalt, BCRYPT_MAXSALT, (const u_int8_t *) salt); 208 salt_len = BCRYPT_MAXSALT; 209 if (minr <= 'a') 210 key_len = (u_int8_t)(strlen(key) + (minr >= 'a' ? 1 : 0)); 211 else { 212 /* strlen() returns a size_t, but the function calls 213 * below result in implicit casts to a narrower integer 214 * type, so cap key_len at the actual maximum supported 215 * length here to avoid integer wraparound */ 216 key_len = strlen(key); 217 if (key_len > 72) 218 key_len = 72; 219 key_len++; /* include the NUL */ 220 } 221 222 /* Setting up S-Boxes and Subkeys */ 223 Blowfish_initstate(&state); 224 Blowfish_expandstate(&state, csalt, salt_len, 225 (const u_int8_t *) key, key_len); 226 for (k = 0; k < rounds; k++) { 227 Blowfish_expand0state(&state, (const u_int8_t *) key, key_len); 228 Blowfish_expand0state(&state, csalt, salt_len); 229 } 230 231 /* This can be precomputed later */ 232 j = 0; 233 for (i = 0; i < BCRYPT_BLOCKS; i++) 234 cdata[i] = Blowfish_stream2word(ciphertext, 4 * BCRYPT_BLOCKS, &j); 235 236 /* Now do the encryption */ 237 for (k = 0; k < 64; k++) 238 blf_enc(&state, cdata, BCRYPT_BLOCKS / 2); 239 240 for (i = 0; i < BCRYPT_BLOCKS; i++) { 241 ciphertext[4 * i + 3] = cdata[i] & 0xff; 242 cdata[i] = cdata[i] >> 8; 243 ciphertext[4 * i + 2] = cdata[i] & 0xff; 244 cdata[i] = cdata[i] >> 8; 245 ciphertext[4 * i + 1] = cdata[i] & 0xff; 246 cdata[i] = cdata[i] >> 8; 247 ciphertext[4 * i + 0] = cdata[i] & 0xff; 248 } 249 250 251 i = 0; 252 encrypted[i++] = '$'; 253 encrypted[i++] = BCRYPT_VERSION; 254 if (minr) 255 encrypted[i++] = minr; 256 encrypted[i++] = '$'; 257 258 snprintf(encrypted + i, 4, "%2.2u$", logr); 259 260 encode_base64((u_int8_t *) encrypted + i + 3, csalt, BCRYPT_MAXSALT); 261 encode_base64((u_int8_t *) encrypted + strlen(encrypted), ciphertext, 262 4 * BCRYPT_BLOCKS - 1); 263 memset(&state, 0, sizeof(state)); 264 memset(ciphertext, 0, sizeof(ciphertext)); 265 memset(csalt, 0, sizeof(csalt)); 266 memset(cdata, 0, sizeof(cdata)); 267 return encrypted; 268 } 269 270 static void 271 encode_base64(u_int8_t *buffer, u_int8_t *data, u_int16_t len) 272 { 273 u_int8_t *bp = buffer; 274 u_int8_t *p = data; 275 u_int8_t c1, c2; 276 while (p < data + len) { 277 c1 = *p++; 278 *bp++ = Base64Code[(c1 >> 2)]; 279 c1 = (c1 & 0x03) << 4; 280 if (p >= data + len) { 281 *bp++ = Base64Code[c1]; 282 break; 283 } 284 c2 = *p++; 285 c1 |= (c2 >> 4) & 0x0f; 286 *bp++ = Base64Code[c1]; 287 c1 = (c2 & 0x0f) << 2; 288 if (p >= data + len) { 289 *bp++ = Base64Code[c1]; 290 break; 291 } 292 c2 = *p++; 293 c1 |= (c2 >> 6) & 0x03; 294 *bp++ = Base64Code[c1]; 295 *bp++ = Base64Code[c2 & 0x3f]; 296 } 297 *bp = '\0'; 298 } 299 #if 0 300 void 301 main() 302 { 303 char blubber[73]; 304 char salt[100]; 305 char *p; 306 salt[0] = '$'; 307 salt[1] = BCRYPT_VERSION; 308 salt[2] = '$'; 309 310 snprintf(salt + 3, 4, "%2.2u$", 5); 311 312 printf("24 bytes of salt: "); 313 fgets(salt + 6, sizeof(salt) - 6, stdin); 314 salt[99] = 0; 315 printf("72 bytes of password: "); 316 fpurge(stdin); 317 fgets(blubber, sizeof(blubber), stdin); 318 blubber[72] = 0; 319 320 p = crypt(blubber, salt); 321 printf("Passwd entry: %s\n\n", p); 322 323 p = bcrypt_gensalt(5); 324 printf("Generated salt: %s\n", p); 325 p = crypt(blubber, p); 326 printf("Passwd entry: %s\n", p); 327 } 328 #endif 329