/* $OpenBSD: bcrypt.c,v 1.57 2016/08/26 08:25:02 guenther Exp $ */ /* * Copyright (c) 2014 Ted Unangst * Copyright (c) 1997 Niels Provos * * 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 * 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 #include #include #include #include #include #include #include "blf.h" #include "blowfish.h" /* 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 *); /* * 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; snprintf( (char *)salt, saltbuflen, "$2b$%2.2u$", log_rounds ); encode_base64( (char *)salt + 7, csalt, sizeof( csalt ) ); return 0; } /* * the core bcrypt function */ static int bcrypt_hashpass(const char *key, const uint8_t *salt, char *encrypted, size_t encryptedlen) { blf_ctx state; uint32_t rounds, i, k; uint16_t j; size_t key_len; uint8_t salt_len, logr, minor; uint8_t ciphertext[4 * BCRYPT_WORDS] = "OrpheanBeholderScryDoubt"; uint8_t csalt[BCRYPT_MAXSALT]; uint32_t cdata[BCRYPT_WORDS]; if (encryptedlen < BCRYPT_HASHSPACE) goto inval; /* Check and discard "$" identifier */ if (salt[0] != '$') goto inval; salt += 1; if (salt[0] != BCRYPT_VERSION) goto inval; /* Check for minor versions */ switch ((minor = salt[1])) { case 'a': key_len = (uint8_t)(strlen( key ) + 1); break; case 'b': /* strlen() returns a size_t, but the function calls * below result in implicit casts to a narrower integer * type, so cap key_len at the actual maximum supported * length here to avoid integer wraparound */ key_len = strlen( key ); if (key_len > 72) key_len = 72; key_len++; /* include the NUL */ break; default: goto inval; } if (salt[2] != '$') 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)); 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; if (strlen( (char *)salt ) * 3 / 4 < BCRYPT_MAXSALT) goto inval; /* We dont want the base64 salt but the raw data */ if (decode_base64( csalt, BCRYPT_MAXSALT, (char *)salt )) 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 ); for (k = 0; k < rounds; k++) { Blowfish_expand0state( &state, (uint8_t *)key, (uint16_t)key_len ); 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); cdata[i] = cdata[i] >> 8; ciphertext[4 * i + 2] = (uint8_t)(cdata[i] & 0xff); cdata[i] = cdata[i] >> 8; ciphertext[4 * i + 1] = (uint8_t)(cdata[i] & 0xff); cdata[i] = cdata[i] >> 8; ciphertext[4 * i + 0] = (uint8_t)(cdata[i] & 0xff); } 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; } /* * internal utilities */ static const uint8_t Base64Code[] = "./ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"; static const uint8_t index_64[128] = { 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)]) /* * read buflen (after decoding) bytes of data from b64data */ static int decode_base64(uint8_t *buffer, size_t len, const char *b64data) { uint8_t *bp = buffer; const uint8_t *p = (uint8_t *)b64data; uint8_t c1, c2, c3, c4; 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)); if (bp >= buffer + len) break; c3 = CHAR64( *(p + 2) ); if (c3 == 255) return -1; *bp++ = (uint8_t)(((c2 & 0x0f) << 4) | ((c3 & 0x3c) >> 2)); if (bp >= buffer + len) break; c4 = CHAR64( *(p + 3) ); if (c4 == 255) return -1; *bp++ = (uint8_t)(((c3 & 0x03) << 6) | c4); 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) { uint8_t *bp = (uint8_t *)b64buffer; const uint8_t *p = data; uint8_t c1, c2; while (p < data + len) { c1 = *p++; *bp++ = Base64Code[(c1 >> 2)]; c1 = (uint8_t)((c1 & 0x03) << 4); if (p >= data + len) { *bp++ = Base64Code[c1]; break; } c2 = *p++; c1 |= (c2 >> 4) & 0x0f; *bp++ = Base64Code[c1]; c1 = (uint8_t)((c2 & 0x0f) << 2); 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) { static uint8_t gsalt[BCRYPT_SALTSPACE]; bcrypt_initsalt( log_rounds, gsalt, sizeof( gsalt ) ); return gsalt; } static char * bcrypt(const char *pass, const uint8_t *salt) { static char gencrypted[BCRYPT_HASHSPACE]; if (bcrypt_hashpass( pass, salt, gencrypted, sizeof( gencrypted ) ) != 0) return NULL; return gencrypted; }