/* $OpenBSD: bcrypt.c,v 1.36 2014/03/24 00:00:29 tedu 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 /* 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_BLOCKS 6 /* Ciphertext blocks */ #define BCRYPT_MINLOGROUNDS 4 /* we have log2(rounds) in salt */ #define BCRYPT_SALTSPACE (7 + (BCRYPT_MAXSALT * 4 + 2) / 3 + 1) char *bcrypt_gensalt(u_int8_t); static void encode_base64(u_int8_t *, u_int8_t *, u_int16_t); static void decode_base64(u_int8_t *, u_int16_t, u_int8_t *); /* * 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) return -1; arc4random_buf(csalt, sizeof(csalt)); if (log_rounds < 4) log_rounds = 4; else if (log_rounds > 31) log_rounds = 31; snprintf(salt, saltbuflen, "$2a$%2.2u$", log_rounds); encode_base64((uint8_t *)salt + 7, csalt, sizeof(csalt)); return 0; } /* * the core bcrypt function */ static int bcrypt_hashpass(const char *key, const char *salt, char *encrypted, size_t encryptedlen) { blf_ctx state; u_int32_t rounds, i, k; u_int16_t j; size_t key_len; u_int8_t salt_len, logr, minor; u_int8_t ciphertext[4 * BCRYPT_BLOCKS] = "OrpheanBeholderScryDoubt"; u_int8_t csalt[BCRYPT_MAXSALT]; u_int32_t cdata[BCRYPT_BLOCKS]; char arounds[3]; /* Discard "$" identifier */ salt++; if (*salt > BCRYPT_VERSION) { return -1; } /* Check for minor versions */ if (salt[1] != '$') { switch (salt[1]) { case 'a': /* 'ab' should not yield the same as 'abab' */ case 'b': /* cap input length at 72 bytes */ minor = salt[1]; salt++; break; default: return -1; } } else minor = 0; /* Discard version + "$" identifier */ salt += 2; if (salt[2] != '$') /* Out of sync with passwd entry */ return -1; memcpy(arounds, salt, sizeof(arounds)); if (arounds[sizeof(arounds) - 1] != '$') return -1; arounds[sizeof(arounds) - 1] = 0; logr = strtonum(arounds, BCRYPT_MINLOGROUNDS, 31, NULL); if (logr == 0) return -1; /* Computer power doesn't increase linearly, 2^x should be fine */ rounds = 1U << logr; /* Discard num rounds + "$" identifier */ salt += 3; if (strlen(salt) * 3 / 4 < BCRYPT_MAXSALT) return -1; /* We dont want the base64 salt but the raw data */ decode_base64(csalt, BCRYPT_MAXSALT, (u_int8_t *) salt); salt_len = BCRYPT_MAXSALT; if (minor <= 'a') key_len = (u_int8_t)(strlen(key) + (minor >= 'a' ? 1 : 0)); else { /* strlen() returns a size_t, but the function calls * below result in implicit casts to a narrower integer * type, so cap key_len at the actual maximum supported * length here to avoid integer wraparound */ key_len = strlen(key); if (key_len > 72) key_len = 72; key_len++; /* include the NUL */ } /* Setting up S-Boxes and Subkeys */ Blowfish_initstate(&state); Blowfish_expandstate(&state, csalt, salt_len, (u_int8_t *) key, key_len); for (k = 0; k < rounds; k++) { Blowfish_expand0state(&state, (u_int8_t *) key, key_len); Blowfish_expand0state(&state, csalt, salt_len); } /* This can be precomputed later */ j = 0; for (i = 0; i < BCRYPT_BLOCKS; i++) cdata[i] = Blowfish_stream2word(ciphertext, 4 * BCRYPT_BLOCKS, &j); /* Now do the encryption */ for (k = 0; k < 64; k++) blf_enc(&state, cdata, BCRYPT_BLOCKS / 2); for (i = 0; i < BCRYPT_BLOCKS; i++) { ciphertext[4 * i + 3] = cdata[i] & 0xff; cdata[i] = cdata[i] >> 8; ciphertext[4 * i + 2] = cdata[i] & 0xff; cdata[i] = cdata[i] >> 8; ciphertext[4 * i + 1] = cdata[i] & 0xff; cdata[i] = cdata[i] >> 8; ciphertext[4 * i + 0] = cdata[i] & 0xff; } i = 0; encrypted[i++] = '$'; encrypted[i++] = BCRYPT_VERSION; if (minor) encrypted[i++] = minor; encrypted[i++] = '$'; snprintf(encrypted + i, 4, "%2.2u$", logr); encode_base64((u_int8_t *) encrypted + i + 3, csalt, BCRYPT_MAXSALT); encode_base64((u_int8_t *) encrypted + strlen(encrypted), ciphertext, 4 * BCRYPT_BLOCKS - 1); memset(&state, 0, sizeof(state)); memset(ciphertext, 0, sizeof(ciphertext)); memset(csalt, 0, sizeof(csalt)); memset(cdata, 0, sizeof(cdata)); return 0; } /* * user friendly functions */ int bcrypt_newhash(const char *pass, int log_rounds, char *hash, size_t hashlen) { char salt[BCRYPT_SALTSPACE]; if (bcrypt_initsalt(log_rounds, salt, sizeof(salt)) != 0) return -1; if (bcrypt_hashpass(pass, salt, hash, hashlen) != 0) return -1; explicit_bzero(salt, sizeof(salt)); return 0; } int bcrypt_checkpass(const char *pass, const char *goodhash) { char hash[_PASSWORD_LEN]; if (bcrypt_hashpass(pass, goodhash, hash, sizeof(hash)) != 0) return -1; if (strlen(hash) != strlen(goodhash) || timingsafe_bcmp(hash, goodhash, strlen(goodhash)) != 0) return -1; explicit_bzero(hash, sizeof(hash)); return 0; } /* * internal utilities */ const static u_int8_t Base64Code[] = "./ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"; const static u_int8_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 ? 255 : index_64[(c)]) static void decode_base64(u_int8_t *buffer, u_int16_t len, u_int8_t *data) { u_int8_t *bp = buffer; u_int8_t *p = data; u_int8_t c1, c2, c3, c4; while (bp < buffer + len) { c1 = CHAR64(*p); c2 = CHAR64(*(p + 1)); /* Invalid data */ if (c1 == 255 || c2 == 255) break; *bp++ = (c1 << 2) | ((c2 & 0x30) >> 4); if (bp >= buffer + len) break; c3 = CHAR64(*(p + 2)); if (c3 == 255) break; *bp++ = ((c2 & 0x0f) << 4) | ((c3 & 0x3c) >> 2); if (bp >= buffer + len) break; c4 = CHAR64(*(p + 3)); if (c4 == 255) break; *bp++ = ((c3 & 0x03) << 6) | c4; p += 4; } } static void encode_base64(u_int8_t *buffer, u_int8_t *data, u_int16_t len) { u_int8_t *bp = buffer; u_int8_t *p = data; u_int8_t c1, c2; while (p < data + len) { c1 = *p++; *bp++ = Base64Code[(c1 >> 2)]; c1 = (c1 & 0x03) << 4; if (p >= data + len) { *bp++ = Base64Code[c1]; break; } c2 = *p++; c1 |= (c2 >> 4) & 0x0f; *bp++ = Base64Code[c1]; c1 = (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'; } /* * classic interface */ char * bcrypt_gensalt(u_int8_t log_rounds) { static char gsalt[BCRYPT_SALTSPACE]; bcrypt_initsalt(log_rounds, gsalt, sizeof(gsalt)); return gsalt; } char * bcrypt(const char *pass, const char *salt) { static char gencrypted[_PASSWORD_LEN]; static char gerror[2]; /* How do I handle errors ? Return ':' */ strlcpy(gerror, ":", sizeof(gerror)); if (bcrypt_hashpass(pass, salt, gencrypted, sizeof(gencrypted)) != 0) return gerror; return gencrypted; }