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 /* This password hashing algorithm was designed by David Mazieres 35 * <dm@lcs.mit.edu> and works as follows: 36 * 37 * 1. state := InitState () 38 * 2. state := ExpandKey (state, salt, password) 39 * 3. REPEAT rounds: 40 * state := ExpandKey (state, 0, password) 41 * state := ExpandKey (state, 0, salt) 42 * 4. ctext := "OrpheanBeholderScryDoubt" 43 * 5. REPEAT 64: 44 * ctext := Encrypt_ECB (state, ctext); 45 * 6. RETURN Concatenate (salt, ctext); 46 * 47 */ 48 49 /* 50 * FreeBSD implementation by Paul Herman <pherman@frenchfries.net> 51 * and updated by Xin Li <delphij@FreeBSD.org> 52 */ 53 54 #include <stdio.h> 55 #include <stdlib.h> 56 #include <sys/types.h> 57 #include <string.h> 58 #include <pwd.h> 59 #include "blowfish.h" 60 #include "crypt.h" 61 62 /* This implementation is adaptable to current computing power. 63 * You can have up to 2^31 rounds which should be enough for some 64 * time to come. 65 */ 66 67 #define BCRYPT_VERSION '2' 68 #define BCRYPT_MAXSALT 16 /* Precomputation is just so nice */ 69 #define BCRYPT_BLOCKS 6 /* Ciphertext blocks */ 70 #define BCRYPT_MINLOGROUNDS 4 /* we have log2(rounds) in salt */ 71 72 73 static void encode_base64(u_int8_t *, u_int8_t *, u_int16_t); 74 static void decode_base64(u_int8_t *, u_int16_t, const u_int8_t *); 75 76 const static u_int8_t Base64Code[] = 77 "./ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"; 78 79 const static u_int8_t index_64[128] = { 80 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 81 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 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, 0, 1, 54, 55, 85 56, 57, 58, 59, 60, 61, 62, 63, 255, 255, 86 255, 255, 255, 255, 255, 2, 3, 4, 5, 6, 87 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 88 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 89 255, 255, 255, 255, 255, 255, 28, 29, 30, 90 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 91 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 92 51, 52, 53, 255, 255, 255, 255, 255 93 }; 94 #define CHAR64(c) ( (c) > 127 ? 255 : index_64[(c)]) 95 96 static void 97 decode_base64(u_int8_t *buffer, u_int16_t len, const u_int8_t *data) 98 { 99 u_int8_t *bp = buffer; 100 const u_int8_t *p = data; 101 u_int8_t c1, c2, c3, c4; 102 while (bp < buffer + len) { 103 c1 = CHAR64(*p); 104 c2 = CHAR64(*(p + 1)); 105 106 /* Invalid data */ 107 if (c1 == 255 || c2 == 255) 108 break; 109 110 *bp++ = (c1 << 2) | ((c2 & 0x30) >> 4); 111 if (bp >= buffer + len) 112 break; 113 114 c3 = CHAR64(*(p + 2)); 115 if (c3 == 255) 116 break; 117 118 *bp++ = ((c2 & 0x0f) << 4) | ((c3 & 0x3c) >> 2); 119 if (bp >= buffer + len) 120 break; 121 122 c4 = CHAR64(*(p + 3)); 123 if (c4 == 255) 124 break; 125 *bp++ = ((c3 & 0x03) << 6) | c4; 126 127 p += 4; 128 } 129 } 130 131 /* We handle $Vers$log2(NumRounds)$salt+passwd$ 132 i.e. $2$04$iwouldntknowwhattosayetKdJ6iFtacBqJdKe6aW7ou */ 133 134 int 135 crypt_blowfish(const char *key, const char *salt, char *buffer) 136 { 137 blf_ctx state; 138 u_int32_t rounds, i, k; 139 u_int16_t j; 140 size_t key_len; 141 u_int8_t salt_len, logr, minr; 142 u_int8_t ciphertext[4 * BCRYPT_BLOCKS] = "OrpheanBeholderScryDoubt"; 143 u_int8_t csalt[BCRYPT_MAXSALT]; 144 u_int32_t cdata[BCRYPT_BLOCKS]; 145 char arounds[3]; 146 147 /* Defaults */ 148 minr = 'b'; 149 logr = BCRYPT_MINLOGROUNDS; 150 rounds = 1U << logr; 151 152 if (*salt == '$') { 153 /* Discard "$" identifier */ 154 salt++; 155 156 if (*salt > BCRYPT_VERSION) 157 return (-1); 158 159 /* Check for minor versions */ 160 if (salt[1] != '$') { 161 switch (salt[1]) { 162 case 'a': /* 'ab' should not yield the same as 'abab' */ 163 case 'b': /* cap input length at 72 bytes */ 164 case 'y': /* same as 'b', for compatibility 165 * with openwall crypt_blowfish 166 */ 167 minr = salt[1]; 168 salt++; 169 break; 170 default: 171 return (-1); 172 } 173 } else 174 minr = 0; 175 176 /* Discard version + "$" identifier */ 177 salt += 2; 178 179 if (salt[2] != '$') 180 /* Out of sync with passwd entry */ 181 return (-1); 182 183 memcpy(arounds, salt, sizeof(arounds)); 184 if (arounds[sizeof(arounds) - 1] != '$') 185 return (-1); 186 arounds[sizeof(arounds) - 1] = 0; 187 logr = strtonum(arounds, BCRYPT_MINLOGROUNDS, 31, NULL); 188 if (logr == 0) 189 return (-1); 190 /* Computer power doesn't increase linearly, 2^x should be fine */ 191 rounds = 1U << logr; 192 193 /* Discard num rounds + "$" identifier */ 194 salt += 3; 195 } 196 197 if (strlen(salt) * 3 / 4 < BCRYPT_MAXSALT) 198 return (-1); 199 200 /* We dont want the base64 salt but the raw data */ 201 decode_base64(csalt, BCRYPT_MAXSALT, (const u_int8_t *) salt); 202 salt_len = BCRYPT_MAXSALT; 203 if (minr <= 'a') 204 key_len = (u_int8_t)(strlen(key) + (minr >= 'a' ? 1 : 0)); 205 else { 206 /* strlen() returns a size_t, but the function calls 207 * below result in implicit casts to a narrower integer 208 * type, so cap key_len at the actual maximum supported 209 * length here to avoid integer wraparound */ 210 key_len = strlen(key); 211 if (key_len > 72) 212 key_len = 72; 213 key_len++; /* include the NUL */ 214 } 215 216 /* Setting up S-Boxes and Subkeys */ 217 Blowfish_initstate(&state); 218 Blowfish_expandstate(&state, csalt, salt_len, 219 (const u_int8_t *) key, key_len); 220 for (k = 0; k < rounds; k++) { 221 Blowfish_expand0state(&state, (const u_int8_t *) key, key_len); 222 Blowfish_expand0state(&state, csalt, salt_len); 223 } 224 225 /* This can be precomputed later */ 226 j = 0; 227 for (i = 0; i < BCRYPT_BLOCKS; i++) 228 cdata[i] = Blowfish_stream2word(ciphertext, 4 * BCRYPT_BLOCKS, &j); 229 230 /* Now do the encryption */ 231 for (k = 0; k < 64; k++) 232 blf_enc(&state, cdata, BCRYPT_BLOCKS / 2); 233 234 for (i = 0; i < BCRYPT_BLOCKS; i++) { 235 ciphertext[4 * i + 3] = cdata[i] & 0xff; 236 cdata[i] = cdata[i] >> 8; 237 ciphertext[4 * i + 2] = cdata[i] & 0xff; 238 cdata[i] = cdata[i] >> 8; 239 ciphertext[4 * i + 1] = cdata[i] & 0xff; 240 cdata[i] = cdata[i] >> 8; 241 ciphertext[4 * i + 0] = cdata[i] & 0xff; 242 } 243 244 245 *buffer++ = '$'; 246 *buffer++ = BCRYPT_VERSION; 247 if (minr) 248 *buffer++ = minr; 249 *buffer++ = '$'; 250 251 snprintf(buffer, 4, "%2.2u$", logr); 252 buffer += 3; 253 254 encode_base64((u_int8_t *)buffer, csalt, BCRYPT_MAXSALT); 255 buffer += strlen(buffer); 256 encode_base64((u_int8_t *)buffer, ciphertext, 4 * BCRYPT_BLOCKS - 1); 257 memset(&state, 0, sizeof(state)); 258 memset(ciphertext, 0, sizeof(ciphertext)); 259 memset(csalt, 0, sizeof(csalt)); 260 memset(cdata, 0, sizeof(cdata)); 261 return (0); 262 } 263 264 static void 265 encode_base64(u_int8_t *buffer, u_int8_t *data, u_int16_t len) 266 { 267 u_int8_t *bp = buffer; 268 u_int8_t *p = data; 269 u_int8_t c1, c2; 270 while (p < data + len) { 271 c1 = *p++; 272 *bp++ = Base64Code[(c1 >> 2)]; 273 c1 = (c1 & 0x03) << 4; 274 if (p >= data + len) { 275 *bp++ = Base64Code[c1]; 276 break; 277 } 278 c2 = *p++; 279 c1 |= (c2 >> 4) & 0x0f; 280 *bp++ = Base64Code[c1]; 281 c1 = (c2 & 0x0f) << 2; 282 if (p >= data + len) { 283 *bp++ = Base64Code[c1]; 284 break; 285 } 286 c2 = *p++; 287 c1 |= (c2 >> 6) & 0x03; 288 *bp++ = Base64Code[c1]; 289 *bp++ = Base64Code[c2 & 0x3f]; 290 } 291 *bp = '\0'; 292 } 293 #if 0 294 void 295 main() 296 { 297 char blubber[73]; 298 char salt[100]; 299 char *p; 300 salt[0] = '$'; 301 salt[1] = BCRYPT_VERSION; 302 salt[2] = '$'; 303 304 snprintf(salt + 3, 4, "%2.2u$", 5); 305 306 printf("24 bytes of salt: "); 307 fgets(salt + 6, sizeof(salt) - 6, stdin); 308 salt[99] = 0; 309 printf("72 bytes of password: "); 310 fpurge(stdin); 311 fgets(blubber, sizeof(blubber), stdin); 312 blubber[72] = 0; 313 314 p = crypt(blubber, salt); 315 printf("Passwd entry: %s\n\n", p); 316 317 p = bcrypt_gensalt(5); 318 printf("Generated salt: %s\n", p); 319 p = crypt(blubber, p); 320 printf("Passwd entry: %s\n", p); 321 } 322 #endif 323