From 71e2fd608ccc0e6e85833a70df253cf0cfae9607 Mon Sep 17 00:00:00 2001 From: Dimitri Sokolyuk Date: Sun, 18 Sep 2016 20:15:16 +0200 Subject: Add bcrypt_pbdkf --- orig/lib/bcrypt_pbkdf.3 | 69 ++++++++++++++++++++ orig/lib/bcrypt_pbkdf.c | 169 ++++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 238 insertions(+) create mode 100644 orig/lib/bcrypt_pbkdf.3 create mode 100644 orig/lib/bcrypt_pbkdf.c (limited to 'orig/lib') diff --git a/orig/lib/bcrypt_pbkdf.3 b/orig/lib/bcrypt_pbkdf.3 new file mode 100644 index 0000000..eb43d43 --- /dev/null +++ b/orig/lib/bcrypt_pbkdf.3 @@ -0,0 +1,69 @@ +.\" $OpenBSD: bcrypt_pbkdf.3,v 1.6 2014/11/25 03:37:12 tedu Exp $ +.\" +.\" Copyright (c) 2012 Ted Unangst +.\" +.\" 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. +.\" +.Dd $Mdocdate: November 25 2014 $ +.Dt BCRYPT_PBKDF 3 +.Os +.Sh NAME +.Nm bcrypt_pbkdf +.Nd bcrypt password-based key derivation function +.Sh SYNOPSIS +.In util.h +.Ft int +.Fn bcrypt_pbkdf "const char *pass" "size_t pass_len" "const uint8_t *salt" \ + "size_t salt_len" "uint8_t *key" "size_t key_len" "unsigned int rounds" +.Sh DESCRIPTION +The +.Nm +function converts a password into a byte array suitable for use as +an encryption key. +The password and salt values are combined and repeatedly hashed +.Ar rounds +times. +The salt value should be randomly generated beforehand. +The repeated hashing is designed to thwart discovery of the key via +password guessing attacks. +The higher the number of rounds, the slower each attempt will be. +.\" A minimum value of at least 4 is recommended. +.Sh RETURN VALUES +The +.Fn bcrypt_pbkdf +function returns 0 to indicate success and \-1 for failure. +.\" .Sh EXAMPLES +.\" .Sh ERRORS +.Sh SEE ALSO +.Xr bcrypt 3 +.Sh STANDARDS +.Rs +.%A Niels Provos and David Mazieres +.%D June 1999 +.%T A Future-Adaptable Password Scheme +.Re +.Pp +.Rs +.%A B. Kaliski +.%D September 2000 +.%R RFC 2898 +.%T PKCS #5: Password-Based Cryptography Specification Version 2.0 +.Re +.\" .Sh HISTORY +.\" .Sh AUTHORS +.Sh CAVEATS +This implementation deviates slightly from the PBKDF2 standard by mixing +output key bits nonlinearly. +By mixing the output bytes together, an attacker is required to perform +all of the work without taking any shortcuts. +.\" .Sh BUGS diff --git a/orig/lib/bcrypt_pbkdf.c b/orig/lib/bcrypt_pbkdf.c new file mode 100644 index 0000000..cde347c --- /dev/null +++ b/orig/lib/bcrypt_pbkdf.c @@ -0,0 +1,169 @@ +/* $OpenBSD: bcrypt_pbkdf.c,v 1.13 2015/01/12 03:20:04 tedu Exp $ */ +/* + * Copyright (c) 2013 Ted Unangst + * + * 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. + */ + +#include + +#include +#include +#include +#include +#include +#include + +#define MINIMUM(a,b) (((a) < (b)) ? (a) : (b)) + +/* + * pkcs #5 pbkdf2 implementation using the "bcrypt" hash + * + * The bcrypt hash function is derived from the bcrypt password hashing + * function with the following modifications: + * 1. The input password and salt are preprocessed with SHA512. + * 2. The output length is expanded to 256 bits. + * 3. Subsequently the magic string to be encrypted is lengthened and modifed + * to "OxychromaticBlowfishSwatDynamite" + * 4. The hash function is defined to perform 64 rounds of initial state + * expansion. (More rounds are performed by iterating the hash.) + * + * Note that this implementation pulls the SHA512 operations into the caller + * as a performance optimization. + * + * One modification from official pbkdf2. Instead of outputting key material + * linearly, we mix it. pbkdf2 has a known weakness where if one uses it to + * generate (e.g.) 512 bits of key material for use as two 256 bit keys, an + * attacker can merely run once through the outer loop, but the user + * always runs it twice. Shuffling output bytes requires computing the + * entirety of the key material to assemble any subkey. This is something a + * wise caller could do; we just do it for you. + */ + +#define BCRYPT_WORDS 8 +#define BCRYPT_HASHSIZE (BCRYPT_WORDS * 4) + +static void +bcrypt_hash(uint8_t *sha2pass, uint8_t *sha2salt, uint8_t *out) +{ + blf_ctx state; + uint8_t ciphertext[BCRYPT_HASHSIZE] = + "OxychromaticBlowfishSwatDynamite"; + uint32_t cdata[BCRYPT_WORDS]; + int i; + uint16_t j; + size_t shalen = SHA512_DIGEST_LENGTH; + + /* key expansion */ + Blowfish_initstate(&state); + Blowfish_expandstate(&state, sha2salt, shalen, sha2pass, shalen); + for (i = 0; i < 64; i++) { + Blowfish_expand0state(&state, sha2salt, shalen); + Blowfish_expand0state(&state, sha2pass, shalen); + } + + /* encryption */ + j = 0; + for (i = 0; i < BCRYPT_WORDS; i++) + cdata[i] = Blowfish_stream2word(ciphertext, sizeof(ciphertext), + &j); + for (i = 0; i < 64; i++) + blf_enc(&state, cdata, sizeof(cdata) / sizeof(uint64_t)); + + /* copy out */ + for (i = 0; i < BCRYPT_WORDS; i++) { + out[4 * i + 3] = (cdata[i] >> 24) & 0xff; + out[4 * i + 2] = (cdata[i] >> 16) & 0xff; + out[4 * i + 1] = (cdata[i] >> 8) & 0xff; + out[4 * i + 0] = cdata[i] & 0xff; + } + + /* zap */ + explicit_bzero(ciphertext, sizeof(ciphertext)); + explicit_bzero(cdata, sizeof(cdata)); + explicit_bzero(&state, sizeof(state)); +} + +int +bcrypt_pbkdf(const char *pass, size_t passlen, const uint8_t *salt, size_t saltlen, + uint8_t *key, size_t keylen, unsigned int rounds) +{ + SHA2_CTX ctx; + uint8_t sha2pass[SHA512_DIGEST_LENGTH]; + uint8_t sha2salt[SHA512_DIGEST_LENGTH]; + uint8_t out[BCRYPT_HASHSIZE]; + uint8_t tmpout[BCRYPT_HASHSIZE]; + uint8_t countsalt[4]; + size_t i, j, amt, stride; + uint32_t count; + size_t origkeylen = keylen; + + /* nothing crazy */ + if (rounds < 1) + return -1; + if (passlen == 0 || saltlen == 0 || keylen == 0 || + keylen > sizeof(out) * sizeof(out)) + return -1; + stride = (keylen + sizeof(out) - 1) / sizeof(out); + amt = (keylen + stride - 1) / stride; + + /* collapse password */ + SHA512Init(&ctx); + SHA512Update(&ctx, pass, passlen); + SHA512Final(sha2pass, &ctx); + + + /* generate key, sizeof(out) at a time */ + for (count = 1; keylen > 0; count++) { + countsalt[0] = (count >> 24) & 0xff; + countsalt[1] = (count >> 16) & 0xff; + countsalt[2] = (count >> 8) & 0xff; + countsalt[3] = count & 0xff; + + /* first round, salt is salt */ + SHA512Init(&ctx); + SHA512Update(&ctx, salt, saltlen); + SHA512Update(&ctx, countsalt, sizeof(countsalt)); + SHA512Final(sha2salt, &ctx); + bcrypt_hash(sha2pass, sha2salt, tmpout); + memcpy(out, tmpout, sizeof(out)); + + for (i = 1; i < rounds; i++) { + /* subsequent rounds, salt is previous output */ + SHA512Init(&ctx); + SHA512Update(&ctx, tmpout, sizeof(tmpout)); + SHA512Final(sha2salt, &ctx); + bcrypt_hash(sha2pass, sha2salt, tmpout); + for (j = 0; j < sizeof(out); j++) + out[j] ^= tmpout[j]; + } + + /* + * pbkdf2 deviation: output the key material non-linearly. + */ + amt = MINIMUM(amt, keylen); + for (i = 0; i < amt; i++) { + size_t dest = i * stride + (count - 1); + if (dest >= origkeylen) + break; + key[dest] = out[i]; + } + keylen -= i; + } + + /* zap */ + explicit_bzero(&ctx, sizeof(ctx)); + explicit_bzero(out, sizeof(out)); + + return 0; +} -- cgit v1.2.3