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 const static u_int8_t Base64Code[] = 79 "./ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"; 80 81 const static u_int8_t index_64[128] = { 82 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 83 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 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, 0, 1, 54, 55, 87 56, 57, 58, 59, 60, 61, 62, 63, 255, 255, 88 255, 255, 255, 255, 255, 2, 3, 4, 5, 6, 89 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 90 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 91 255, 255, 255, 255, 255, 255, 28, 29, 30, 92 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 93 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 94 51, 52, 53, 255, 255, 255, 255, 255 95 }; 96 #define CHAR64(c) ( (c) > 127 ? 255 : index_64[(c)]) 97 98 static void 99 decode_base64(u_int8_t *buffer, u_int16_t len, const u_int8_t *data) 100 { 101 u_int8_t *bp = buffer; 102 const u_int8_t *p = data; 103 u_int8_t c1, c2, c3, c4; 104 while (bp < buffer + len) { 105 c1 = CHAR64(*p); 106 c2 = CHAR64(*(p + 1)); 107 108 /* Invalid data */ 109 if (c1 == 255 || c2 == 255) 110 break; 111 112 *bp++ = (c1 << 2) | ((c2 & 0x30) >> 4); 113 if (bp >= buffer + len) 114 break; 115 116 c3 = CHAR64(*(p + 2)); 117 if (c3 == 255) 118 break; 119 120 *bp++ = ((c2 & 0x0f) << 4) | ((c3 & 0x3c) >> 2); 121 if (bp >= buffer + len) 122 break; 123 124 c4 = CHAR64(*(p + 3)); 125 if (c4 == 255) 126 break; 127 *bp++ = ((c3 & 0x03) << 6) | c4; 128 129 p += 4; 130 } 131 } 132 133 /* We handle $Vers$log2(NumRounds)$salt+passwd$ 134 i.e. $2$04$iwouldntknowwhattosayetKdJ6iFtacBqJdKe6aW7ou */ 135 136 int 137 crypt_blowfish(const char *key, const char *salt, char *buffer) 138 { 139 blf_ctx state; 140 u_int32_t rounds, i, k; 141 u_int16_t j; 142 size_t key_len; 143 u_int8_t salt_len, logr, minr; 144 u_int8_t ciphertext[4 * BCRYPT_BLOCKS] = "OrpheanBeholderScryDoubt"; 145 u_int8_t csalt[BCRYPT_MAXSALT]; 146 u_int32_t cdata[BCRYPT_BLOCKS]; 147 char arounds[3]; 148 149 /* Defaults */ 150 minr = 'b'; 151 logr = BCRYPT_MINLOGROUNDS; 152 rounds = 1U << logr; 153 154 if (*salt == '$') { 155 /* Discard "$" identifier */ 156 salt++; 157 158 if (*salt > BCRYPT_VERSION) 159 return (-1); 160 161 /* Check for minor versions */ 162 if (salt[1] != '$') { 163 switch (salt[1]) { 164 case 'a': /* 'ab' should not yield the same as 'abab' */ 165 case 'b': /* cap input length at 72 bytes */ 166 case 'y': /* same as 'b', for compatibility 167 * with openwall crypt_blowfish 168 */ 169 minr = salt[1]; 170 salt++; 171 break; 172 default: 173 return (-1); 174 } 175 } else 176 minr = 0; 177 178 /* Discard version + "$" identifier */ 179 salt += 2; 180 181 if (salt[2] != '$') 182 /* Out of sync with passwd entry */ 183 return (-1); 184 185 memcpy(arounds, salt, sizeof(arounds)); 186 if (arounds[sizeof(arounds) - 1] != '$') 187 return (-1); 188 arounds[sizeof(arounds) - 1] = 0; 189 logr = strtonum(arounds, BCRYPT_MINLOGROUNDS, 31, NULL); 190 if (logr == 0) 191 return (-1); 192 /* Computer power doesn't increase linearly, 2^x should be fine */ 193 rounds = 1U << logr; 194 195 /* Discard num rounds + "$" identifier */ 196 salt += 3; 197 } 198 199 if (strlen(salt) * 3 / 4 < BCRYPT_MAXSALT) 200 return (-1); 201 202 /* We dont want the base64 salt but the raw data */ 203 decode_base64(csalt, BCRYPT_MAXSALT, (const u_int8_t *) salt); 204 salt_len = BCRYPT_MAXSALT; 205 if (minr <= 'a') 206 key_len = (u_int8_t)(strlen(key) + (minr >= 'a' ? 1 : 0)); 207 else { 208 /* strlen() returns a size_t, but the function calls 209 * below result in implicit casts to a narrower integer 210 * type, so cap key_len at the actual maximum supported 211 * length here to avoid integer wraparound */ 212 key_len = strlen(key); 213 if (key_len > 72) 214 key_len = 72; 215 key_len++; /* include the NUL */ 216 } 217 218 /* Setting up S-Boxes and Subkeys */ 219 Blowfish_initstate(&state); 220 Blowfish_expandstate(&state, csalt, salt_len, 221 (const u_int8_t *) key, key_len); 222 for (k = 0; k < rounds; k++) { 223 Blowfish_expand0state(&state, (const u_int8_t *) key, key_len); 224 Blowfish_expand0state(&state, csalt, salt_len); 225 } 226 227 /* This can be precomputed later */ 228 j = 0; 229 for (i = 0; i < BCRYPT_BLOCKS; i++) 230 cdata[i] = Blowfish_stream2word(ciphertext, 4 * BCRYPT_BLOCKS, &j); 231 232 /* Now do the encryption */ 233 for (k = 0; k < 64; k++) 234 blf_enc(&state, cdata, BCRYPT_BLOCKS / 2); 235 236 for (i = 0; i < BCRYPT_BLOCKS; i++) { 237 ciphertext[4 * i + 3] = cdata[i] & 0xff; 238 cdata[i] = cdata[i] >> 8; 239 ciphertext[4 * i + 2] = cdata[i] & 0xff; 240 cdata[i] = cdata[i] >> 8; 241 ciphertext[4 * i + 1] = cdata[i] & 0xff; 242 cdata[i] = cdata[i] >> 8; 243 ciphertext[4 * i + 0] = cdata[i] & 0xff; 244 } 245 246 247 *buffer++ = '$'; 248 *buffer++ = BCRYPT_VERSION; 249 if (minr) 250 *buffer++ = minr; 251 *buffer++ = '$'; 252 253 snprintf(buffer, 4, "%2.2u$", logr); 254 buffer += 3; 255 256 encode_base64((u_int8_t *)buffer, csalt, BCRYPT_MAXSALT); 257 buffer += strlen(buffer); 258 encode_base64((u_int8_t *)buffer, ciphertext, 4 * BCRYPT_BLOCKS - 1); 259 memset(&state, 0, sizeof(state)); 260 memset(ciphertext, 0, sizeof(ciphertext)); 261 memset(csalt, 0, sizeof(csalt)); 262 memset(cdata, 0, sizeof(cdata)); 263 return (0); 264 } 265 266 static void 267 encode_base64(u_int8_t *buffer, u_int8_t *data, u_int16_t len) 268 { 269 u_int8_t *bp = buffer; 270 u_int8_t *p = data; 271 u_int8_t c1, c2; 272 while (p < data + len) { 273 c1 = *p++; 274 *bp++ = Base64Code[(c1 >> 2)]; 275 c1 = (c1 & 0x03) << 4; 276 if (p >= data + len) { 277 *bp++ = Base64Code[c1]; 278 break; 279 } 280 c2 = *p++; 281 c1 |= (c2 >> 4) & 0x0f; 282 *bp++ = Base64Code[c1]; 283 c1 = (c2 & 0x0f) << 2; 284 if (p >= data + len) { 285 *bp++ = Base64Code[c1]; 286 break; 287 } 288 c2 = *p++; 289 c1 |= (c2 >> 6) & 0x03; 290 *bp++ = Base64Code[c1]; 291 *bp++ = Base64Code[c2 & 0x3f]; 292 } 293 *bp = '\0'; 294 } 295 #if 0 296 void 297 main() 298 { 299 char blubber[73]; 300 char salt[100]; 301 char *p; 302 salt[0] = '$'; 303 salt[1] = BCRYPT_VERSION; 304 salt[2] = '$'; 305 306 snprintf(salt + 3, 4, "%2.2u$", 5); 307 308 printf("24 bytes of salt: "); 309 fgets(salt + 6, sizeof(salt) - 6, stdin); 310 salt[99] = 0; 311 printf("72 bytes of password: "); 312 fpurge(stdin); 313 fgets(blubber, sizeof(blubber), stdin); 314 blubber[72] = 0; 315 316 p = crypt(blubber, salt); 317 printf("Passwd entry: %s\n\n", p); 318 319 p = bcrypt_gensalt(5); 320 printf("Generated salt: %s\n", p); 321 p = crypt(blubber, p); 322 printf("Passwd entry: %s\n", p); 323 } 324 #endif 325