nettle-bugs

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[PATCH] (revision 3.1) Added bcrypt() support.
by Stephen R. van den Berg 07 Apr '20

07 Apr '20

--- Makefile.in | 2 +- base64-decode.c | 17 +- blowfish-bcrypt.c | 511 ++++++++++++++++++++++++++++++ blowfish.h => blowfish-internal.h | 51 +-- blowfish.c | 23 +- blowfish.h | 15 + nettle.texinfo | 67 ++++ 7 files changed, 620 insertions(+), 66 deletions(-) create mode 100644 blowfish-bcrypt.c copy blowfish.h => blowfish-internal.h (50%) diff --git a/Makefile.in b/Makefile.in index ddc30428..bfb7ac57 100644 --- a/Makefile.in +++ b/Makefile.in @@ -73,7 +73,7 @@ nettle_SOURCES = aes-decrypt-internal.c aes-decrypt.c \ aes256-set-encrypt-key.c aes256-set-decrypt-key.c \ aes256-meta.c \ arcfour.c arcfour-crypt.c \ - arctwo.c arctwo-meta.c blowfish.c \ + arctwo.c arctwo-meta.c blowfish.c blowfish-bcrypt.c \ base16-encode.c base16-decode.c base16-meta.c \ base64-encode.c base64-decode.c base64-meta.c \ base64url-encode.c base64url-decode.c base64url-meta.c \ diff --git a/base64-decode.c b/base64-decode.c index b993117a..9273224a 100644 --- a/base64-decode.c +++ b/base64-decode.c @@ -45,7 +45,7 @@ void base64_decode_init(struct base64_decode_ctx *ctx) { - static const signed char base64_decode_table[0x100] = + static const signed char base64_decode_table[0x80] = { /* White space is HT, VT, FF, CR, LF and SPC */ -1, -1, -1, -1, -1, -1, -1, -1, -1, -2, -2, -2, -2, -2, -1, -1, @@ -56,14 +56,6 @@ base64_decode_init(struct base64_decode_ctx *ctx) 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -1, -1, -1, -1, -1, -1, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, -1, -1, -1, -1, -1, - -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, - -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, - -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, - -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, - -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, - -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, - -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, - -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, }; ctx->word = ctx->bits = ctx->padding = 0; @@ -75,7 +67,12 @@ base64_decode_single(struct base64_decode_ctx *ctx, uint8_t *dst, char src) { - int data = ctx->table[(uint8_t) src]; + int data; + + if ((uint8_t) src > 0x7f) + return -1; + + data = ctx->table[(uint8_t) src]; switch(data) { diff --git a/blowfish-bcrypt.c b/blowfish-bcrypt.c new file mode 100644 index 00000000..e573c86e --- /dev/null +++ b/blowfish-bcrypt.c @@ -0,0 +1,511 @@ +/* blowfish-bcrypt.c + + The blowfish bcrypt implementation. + + Copyright (c) 2020 Stephen R. van den Berg + + This file is part of GNU Nettle. + + GNU Nettle is free software: you can redistribute it and/or + modify it under the terms of either: + + * the GNU Lesser General Public License as published by the Free + Software Foundation; either version 3 of the License, or (at your + option) any later version. + + or + + * the GNU General Public License as published by the Free + Software Foundation; either version 2 of the License, or (at your + option) any later version. + + or both in parallel, as here. + + GNU Nettle is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + General Public License for more details. + + You should have received copies of the GNU General Public License and + the GNU Lesser General Public License along with this program. If + not, see http://www.gnu.org/licenses/. +*/ + +#if HAVE_CONFIG_H +#include "config.h" +#endif + +#include <assert.h> +#include <string.h> +#include <stdlib.h> + +#include "blowfish.h" +#include "blowfish-internal.h" +#include "base64.h" + +#include "macros.h" + +#define CRYPTPLEN 7 +#define SALTLEN ((BLOWFISH_BCRYPT_BINSALT_SIZE*8+5) / 6) + +#define HASHOFFSET (CRYPTPLEN + SALTLEN) + +static const signed char radix64_decode_table[0x80] = { + /* White space is HT, VT, FF, CR, LF and SPC */ + -1, -1, -1, -1, -1, -1, -1, -1, -1, -2, -2, -2, -2, -2, -1, -1, + -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, + -2, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 0, 1, + 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, -1, -1, -1, -3, -1, -1, + -1, 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, -1, -1, -1, -1, -1, + -1, 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, -1, -1, -1, -1, -1, +}; + +static const char radix64_encode_table[64] = + "./ABCDEFGHIJKLMNOPQRSTUVWXYZ" + "abcdefghijklmnopqrstuvwxyz" + "0123456789"; + +int +blowfish_bcrypt_verify(const char *key, + const char *hashed) +{ + char newhash[BLOWFISH_BCRYPT_HASH_SIZE]; + + return blowfish_bcrypt_hash(sizeof newhash, + newhash, key, hashed, -1, (void*)0) + && !strcmp(newhash, hashed); +} + +static char *encode_radix64(char *dst, size_t len, const uint8_t *src) +{ + struct base64_encode_ctx ctx; + base64_encode_init(&ctx); + ctx.alphabet = radix64_encode_table; + dst += base64_encode_update(&ctx, dst, len, src); + dst += base64_encode_final(&ctx, dst); + *--dst = '\0'; /* Strip the trailing = */ + return dst; +} + +/* + * Large parts of the code below are based on public domain sources. + * The comments and copyright notices have been preserved. + * Any code added or modified by me is licensed under the + * licenses listed above. -- Stephen R. van den Berg + */ + +/* + * This code comes from John the Ripper password cracker, with reentrant + * and crypt(3) interfaces added, but optimizations specific to password + * cracking removed. + * + * Written by Solar Designer <solar at openwall.com> in 1998-2015. + * No copyright is claimed, and the software is hereby placed in the public + * domain. In case this attempt to disclaim copyright and place the software + * in the public domain is deemed null and void, then the software is + * Copyright (c) 1998-2015 Solar Designer and it is hereby released to the + * general public under the following terms: + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted. + * + * There's ABSOLUTELY NO WARRANTY, express or implied. + * + * It is my intent that you should be able to use this on your system, + * as part of a software package, or anywhere else to improve security, + * ensure compatibility, or for any other purpose. I would appreciate + * it if you give credit where it is due and keep your modifications in + * the public domain as well, but I don't require that in order to let + * you place this code and any modifications you make under a license + * of your choice. + * + * This implementation is fully compatible with OpenBSD's bcrypt.c for prefix + * "$2b$", originally by Niels Provos <provos at citi.umich.edu>, and it uses + * some of his ideas. The password hashing algorithm was designed by David + * Mazieres <dm at lcs.mit.edu>. For information on the level of + * compatibility for bcrypt hash prefixes other than "$2b$", please refer to + * the comments in set_key() below and to the included crypt(3) man page. + */ + +typedef uint32_t bf_key[_BLOWFISH_ROUNDS + 2]; + +/* + * Magic IV for 64 Blowfish encryptions that we do at the end. + * The string is "OrpheanBeholderScryDoubt" on big-endian. + */ +static uint32_t magic_w[6] = { + 0x4F727068, 0x65616E42, 0x65686F6C, + 0x64657253, 0x63727944, 0x6F756274 +}; + +static void swap32(uint32_t *x, int count) +{ +#if !WORDS_BIGENDIAN + do { + uint32_t tmp = *x; + tmp = (tmp << 16) | (tmp >> 16); + *x++ = ((tmp & 0x00FF00FF) << 8) | ((tmp >> 8) & 0x00FF00FF); + } while (--count); +#endif +} + +static void set_xkey(const char *key, bf_key expanded, bf_key initial, + unsigned bug, uint32_t safety) +{ + const char *ptr = key; + unsigned i, j; + uint32_t sign, diff, tmp[2]; + +/* + * There was a sign extension bug in older revisions of this function. While + * we would have liked to simply fix the bug and move on, we have to provide + * a backwards compatibility feature (essentially the bug) for some systems and + * a safety measure for some others. The latter is needed because for certain + * multiple inputs to the buggy algorithm there exist easily found inputs to + * the correct algorithm that produce the same hash. Thus, we optionally + * deviate from the correct algorithm just enough to avoid such collisions. + * While the bug itself affected the majority of passwords containing + * characters with the 8th bit set (although only a percentage of those in a + * collision-producing way), the anti-collision safety measure affects + * only a subset of passwords containing the '\xff' character (not even all of + * those passwords, just some of them). This character is not found in valid + * UTF-8 sequences and is rarely used in popular 8-bit character encodings. + * Thus, the safety measure is unlikely to cause much annoyance, and is a + * reasonable tradeoff to use when authenticating against existing hashes that + * are not reliably known to have been computed with the correct algorithm. + * + * We use an approach that tries to minimize side-channel leaks of password + * information - that is, we mostly use fixed-cost bitwise operations instead + * of branches or table lookups. (One conditional branch based on password + * length remains. It is not part of the bug aftermath, though, and is + * difficult and possibly unreasonable to avoid given the use of C strings by + * the caller, which results in similar timing leaks anyway.) + * + * For actual implementation, we set an array index in the variable "bug" + * (0 means no bug, 1 means sign extension bug emulation) and a flag in the + * variable "safety" (bit 16 is set when the safety measure is requested). + * Valid combinations of settings are: + * + * Prefix "$2a$": bug = 0, safety = 0x10000 + * Prefix "$2b$": bug = 0, safety = 0 + * Prefix "$2x$": bug = 1, safety = 0 + * Prefix "$2y$": bug = 0, safety = 0 + */ + + sign = diff = 0; + + for (i = 0; i < _BLOWFISH_ROUNDS + 2; i++) { + tmp[0] = tmp[1] = 0; + for (j = 0; j < 4; j++) { + tmp[0] <<= 8; + tmp[0] |= (unsigned char)*ptr; /* correct */ + tmp[1] <<= 8; + tmp[1] |= (signed char)*ptr; /* bug */ +/* + * Sign extension in the first char has no effect - nothing to overwrite yet, + * and those extra 24 bits will be fully shifted out of the 32-bit word. For + * chars 2, 3, 4 in each four-char block, we set bit 7 of "sign" if sign + * extension in tmp[1] occurs. Once this flag is set, it remains set. + */ + if (j) + sign |= tmp[1] & 0x80; + if (!*ptr) + ptr = key; + else + ptr++; + } + diff |= tmp[0] ^ tmp[1]; /* Non-zero on any differences */ + + expanded[i] = tmp[bug]; + initial[i] = _nettle_blowfish_initial_ctx.p[i] ^ tmp[bug]; + } + +/* + * At this point, "diff" is zero if the correct and buggy algorithms produced + * exactly the same result. If so and if "sign" is non-zero, which indicates + * that there was a non-benign sign extension, this means that we have a + * collision between the correctly computed hash for this password and a set of + * passwords that could be supplied to the buggy algorithm. Our safety measure + * is meant to protect from such many-buggy to one-correct collisions, by + * deviating from the correct algorithm in such cases. Let's check for this. + */ + diff |= diff >> 16; /* still zero if exact match */ + diff &= 0xffff; /* ditto */ + diff += 0xffff; /* bit 16 set if "diff" was non-zero (on non-match) */ + sign <<= 9; /* move the non-benign sign extension flag to bit 16 */ + sign &= ~diff & safety; /* action needed? */ + +/* + * If we have determined that we need to deviate from the correct algorithm, + * flip bit 16 in initial expanded key. (The choice of 16 is arbitrary, but + * let's stick to it now. It came out of the approach we used above, and it's + * not any worse than any other choice we could make.) + * + * It is crucial that we don't do the same to the expanded key used in the main + * Eksblowfish loop. By doing it to only one of these two, we deviate from a + * state that could be directly specified by a password to the buggy algorithm + * (and to the fully correct one as well, but that's a side-effect). + */ + initial[0] ^= sign; +} + +static int ibcrypt(size_t length, char *dst, + const char *key, const char *scheme, + int minlog2rounds, + int log2rounds, const uint8_t *salt) +{ + struct { + struct blowfish_ctx ctx; + bf_key expanded_key; + union { + uint32_t salt[4]; + uint32_t output[6]; + } binary; + } data; + uint8_t psalt[BLOWFISH_BCRYPT_BINSALT_SIZE]; + uint32_t L, R; + uint32_t *ptr; + uint32_t count; + int i; + size_t schemelen = strlen(scheme); + unsigned cscheme; + unsigned bug = 0; + uint32_t safety = 0; + if (length < BLOWFISH_BCRYPT_HASH_SIZE || + schemelen < 2) + return 0; + + if (schemelen >= 3 && *scheme++ != '$') + return 0; + if (*scheme++ != '2') + return 0; + + switch (cscheme = *scheme++) { + default: + return 0; + case 'a': safety = 0x10000; + break; + case 'x': bug = 1; + break; + case 'b': case 'y': + break; + } + + if (schemelen >= 4) { + if (*scheme++ != '$') + return 0; + if (schemelen >= 6) { + if (log2rounds < 0) + log2rounds = atoi(scheme); + scheme += 2; + if (schemelen >= CRYPTPLEN && *scheme++ != '$') + return 0; + if (schemelen >= HASHOFFSET && !salt) { + struct base64_decode_ctx ctx; + size_t saltlen = BLOWFISH_BCRYPT_BINSALT_SIZE; + + base64_decode_init(&ctx); + ctx.table = radix64_decode_table; + + if (!base64_decode_update(&ctx, &saltlen, (uint8_t *) data.binary.salt, + SALTLEN, scheme) + || saltlen != BLOWFISH_BCRYPT_BINSALT_SIZE) + return 0; + } + } + } + + if (salt) + memcpy(data.binary.salt, salt, BLOWFISH_BCRYPT_BINSALT_SIZE); + else if (schemelen < HASHOFFSET) + return 0; + memcpy(psalt, data.binary.salt, BLOWFISH_BCRYPT_BINSALT_SIZE); + swap32(data.binary.salt, 4); + + if (log2rounds < minlog2rounds || log2rounds > 31) + return 0; + count = (uint32_t)1 << log2rounds; + + set_xkey(key, data.expanded_key, data.ctx.p, bug, safety); + memcpy(data.ctx.s, _nettle_blowfish_initial_ctx.s, sizeof(data.ctx.s)); + + L = R = 0; + for (i = 0; i < _BLOWFISH_ROUNDS + 2; i += 2) { + L ^= data.binary.salt[i & 2]; + R ^= data.binary.salt[(i & 2) + 1]; + _nettle_blowfish_encround(&data.ctx, &L, &R); + data.ctx.p[i] = L; + data.ctx.p[i + 1] = R; + } + + ptr = data.ctx.s[0]; + do { + ptr += 4; + L ^= data.binary.salt[(_BLOWFISH_ROUNDS + 2) & 3]; + R ^= data.binary.salt[(_BLOWFISH_ROUNDS + 3) & 3]; + _nettle_blowfish_encround(&data.ctx, &L, &R); + *(ptr - 4) = L; + *(ptr - 3) = R; + + L ^= data.binary.salt[(_BLOWFISH_ROUNDS + 4) & 3]; + R ^= data.binary.salt[(_BLOWFISH_ROUNDS + 5) & 3]; + _nettle_blowfish_encround(&data.ctx, &L, &R); + *(ptr - 2) = L; + *(ptr - 1) = R; + } while (ptr < &data.ctx.s[3][0xFF]); + + do { + int done; + + for (i = 0; i < _BLOWFISH_ROUNDS + 2; i += 2) { + data.ctx.p[i] ^= data.expanded_key[i]; + data.ctx.p[i + 1] ^= data.expanded_key[i + 1]; + } + + done = 0; + do { + uint32_t tmp1, tmp2, tmp3, tmp4; + + L = R = 0; + ptr = data.ctx.p; + do { + ptr += 2; + _nettle_blowfish_encround(&data.ctx, &L, &R); + *(ptr - 2) = L; + *(ptr - 1) = R; + } while (ptr < &data.ctx.p[_BLOWFISH_ROUNDS + 2]); + + ptr = data.ctx.s[0]; + do { + ptr += 2; + _nettle_blowfish_encround(&data.ctx, &L, &R); + *(ptr - 2) = L; + *(ptr - 1) = R; + } while (ptr < &data.ctx.s[3][0xFF]); + + if (done) + break; + done = 1; + + tmp1 = data.binary.salt[0]; + tmp2 = data.binary.salt[1]; + tmp3 = data.binary.salt[2]; + tmp4 = data.binary.salt[3]; + for (i = 0; i < _BLOWFISH_ROUNDS; i += 4) { + data.ctx.p[i] ^= tmp1; + data.ctx.p[i + 1] ^= tmp2; + data.ctx.p[i + 2] ^= tmp3; + data.ctx.p[i + 3] ^= tmp4; + } + data.ctx.p[16] ^= tmp1; + data.ctx.p[17] ^= tmp2; + } while (1); + } while (--count); + + for (i = 0; i < 6; i += 2) { + L = magic_w[i]; + R = magic_w[i + 1]; + + count = 64; + do + _nettle_blowfish_encround(&data.ctx, &L, &R); + while (--count); + + data.binary.output[i] = L; + data.binary.output[i + 1] = R; + } + + *dst++ = '$'; + *dst++ = '2'; + *dst++ = cscheme; + *dst++ = '$'; + *dst++ = '0' + log2rounds / 10; + *dst++ = '0' + log2rounds % 10; + *dst++ = '$'; + dst = encode_radix64(dst, BLOWFISH_BCRYPT_BINSALT_SIZE, psalt) - 1; + + swap32(data.binary.output, 6); +/* This has to be bug-compatible with the original implementation, so + only encode 23 of the 24 bytes. */ + encode_radix64(dst, 23, (uint8_t *) data.binary.output); + return cscheme; +} + +/* + * Please preserve the runtime self-test. It serves two purposes at once: + * + * 1. We really can't afford the risk of producing incompatible hashes e.g. + * when there's something like gcc bug 26587 again, whereas an application or + * library integrating this code might not also integrate our external tests or + * it might not run them after every build. Even if it does, the miscompile + * might only occur on the production build, but not on a testing build (such + * as because of different optimization settings). It is painful to recover + * from incorrectly-computed hashes - merely fixing whatever broke is not + * enough. Thus, a proactive measure like this self-test is needed. + * + * 2. We don't want to leave sensitive data from our actual password hash + * computation on the stack or in registers. Previous revisions of the code + * would do explicit cleanups, but simply running the self-test after hash + * computation is more reliable. + * + * The performance cost of this quick self-test is around 0.6% at the "$2a$08" + * setting. + */ +int blowfish_bcrypt_hash(size_t length, char *dst, + const char *key, const char *scheme, + int log2rounds, const uint8_t *salt) +{ + const char *test_pw = "8b \xd0\xc1\xd2\xcf\xcc\xd8"; + const char *test_scheme = "$2a$00$abcdefghijklmnopqrstuu"; + static const char * const test_hashes[2] = + {"i1D709vfamulimlGcq0qq3UvuUasvEa\0\x55", /* 'a', 'b', 'y' */ + "VUrPmXD6q/nVSSp7pNDhCR9071IfIRe\0\x55"}; /* 'x' */ + const char *test_hash = test_hashes[0]; + int cscheme; + int ok; + struct { + char s[HASHOFFSET + 1]; + char o[HASHOFFSET + 31 + 1 + 1 + 1]; + } buf; + + if (length) + *dst = '\0'; +/* Hash the supplied password */ + cscheme = ibcrypt(length, dst, key, scheme, 4, log2rounds, salt); + +/* + * Do a quick self-test. It is important that we make both calls to ibcrypt() + * from the same scope such that they likely use the same stack locations, + * which makes the second call overwrite the first call's sensitive data on the + * stack and makes it more likely that any alignment related issues would be + * detected by the self-test. + */ + memcpy(buf.s, test_scheme, sizeof(buf.s)); + + if (cscheme) + test_hash = test_hashes[(buf.s[2] = cscheme) == 'x']; + + memset(buf.o, 0x55, sizeof(buf.o)); + buf.o[sizeof(buf.o) - 1] = 0; + ok = ibcrypt(sizeof(buf.o) - (1 + 1), buf.o, test_pw, + buf.s, 0, -1, (void*)0); + + ok = (ok && + !memcmp(buf.o, buf.s, HASHOFFSET) && + !memcmp(buf.o + HASHOFFSET, test_hash, 31 + 1 + 1 + 1)); + + { + const char *k = "\xff\xa3" "34" "\xff\xff\xff\xa3" "345"; + bf_key ae, ai, ye, yi; + set_xkey(k, ae, ai, 0, 0x10000); /* $2a$ */ + set_xkey(k, ye, yi, 0, 0); /* $2y$ */ + ai[0] ^= 0x10000; /* undo the safety (for comparison) */ + ok = ok && ai[0] == 0xdb9c59bc && ye[17] == 0x33343500 && + !memcmp(ae, ye, sizeof(ae)) && + !memcmp(ai, yi, sizeof(ai)); + } + + return ok && !!cscheme; +} diff --git a/blowfish.h b/blowfish-internal.h similarity index 50% copy from blowfish.h copy to blowfish-internal.h index bcdc7cb6..da28fa34 100644 --- a/blowfish.h +++ b/blowfish-internal.h @@ -1,4 +1,4 @@ -/* blowfish.h +/* blowfish-internal.h Blowfish block cipher. @@ -32,8 +32,8 @@ not, see http://www.gnu.org/licenses/. */ -#ifndef NETTLE_BLOWFISH_H_INCLUDED -#define NETTLE_BLOWFISH_H_INCLUDED +#ifndef NETTLE_BLOWFISH_INTERNAL_H_INCLUDED +#define NETTLE_BLOWFISH_INTERNAL_H_INCLUDED #include "nettle-types.h" @@ -41,49 +41,12 @@ extern "C" { #endif -/* Name mangling */ -#define blowfish_set_key nettle_blowfish_set_key -#define blowfish128_set_key nettle_blowfish128_set_key -#define blowfish_encrypt nettle_blowfish_encrypt -#define blowfish_decrypt nettle_blowfish_decrypt - -#define BLOWFISH_BLOCK_SIZE 8 - -/* Variable key size between 64 and 448 bits. */ -#define BLOWFISH_MIN_KEY_SIZE 8 -#define BLOWFISH_MAX_KEY_SIZE 56 - -/* Default to 128 bits */ -#define BLOWFISH_KEY_SIZE 16 - -#define BLOWFISH128_KEY_SIZE 16 - -#define _BLOWFISH_ROUNDS 16 - -struct blowfish_ctx -{ - uint32_t s[4][256]; - uint32_t p[_BLOWFISH_ROUNDS+2]; -}; - -/* Returns 0 for weak keys, otherwise 1. */ -int -blowfish_set_key(struct blowfish_ctx *ctx, - size_t length, const uint8_t *key); -int -blowfish128_set_key(struct blowfish_ctx *ctx, const uint8_t *key); - -void -blowfish_encrypt(const struct blowfish_ctx *ctx, - size_t length, uint8_t *dst, - const uint8_t *src); -void -blowfish_decrypt(const struct blowfish_ctx *ctx, - size_t length, uint8_t *dst, - const uint8_t *src); +extern const struct blowfish_ctx _nettle_blowfish_initial_ctx; +extern void _nettle_blowfish_encround (const struct blowfish_ctx *ctx, + uint32_t * ret_xl, uint32_t * ret_xr); #ifdef __cplusplus } #endif -#endif /* NETTLE_BLOWFISH_H_INCLUDED */ +#endif /* NETTLE_BLOWFISH_INTERNAL_H_INCLUDED */ diff --git a/blowfish.c b/blowfish.c index 52040f13..e73caffe 100644 --- a/blowfish.c +++ b/blowfish.c @@ -54,12 +54,13 @@ #include <assert.h> #include "blowfish.h" +#include "blowfish-internal.h" #include "macros.h" /* precomputed S boxes */ -static const struct blowfish_ctx -initial_ctx = { +const struct blowfish_ctx +_nettle_blowfish_initial_ctx = { { { /* ks0 */ 0xD1310BA6, 0x98DFB5AC, 0x2FFD72DB, 0xD01ADFB7, 0xB8E1AFED, 0x6A267E96, @@ -261,8 +262,8 @@ initial_ctx = { #define R(c, l,r,i) do { l ^= c->p[i]; r ^= F(c,l); } while(0) -static void -encrypt (const struct blowfish_ctx *ctx, uint32_t * ret_xl, +void +_nettle_blowfish_encround (const struct blowfish_ctx *ctx, uint32_t * ret_xl, uint32_t * ret_xr) { uint32_t xl, xr; @@ -295,7 +296,7 @@ encrypt (const struct blowfish_ctx *ctx, uint32_t * ret_xl, } static void -decrypt (const struct blowfish_ctx *ctx, uint32_t * ret_xl, uint32_t * ret_xr) +decround (const struct blowfish_ctx *ctx, uint32_t * ret_xl, uint32_t * ret_xr) { uint32_t xl, xr; @@ -339,7 +340,7 @@ blowfish_encrypt (const struct blowfish_ctx *ctx, d1 = READ_UINT32(src); d2 = READ_UINT32(src+4); - encrypt (ctx, &d1, &d2); + _nettle_blowfish_encround (ctx, &d1, &d2); dst[0] = (d1 >> 24) & 0xff; dst[1] = (d1 >> 16) & 0xff; dst[2] = (d1 >> 8) & 0xff; @@ -361,7 +362,7 @@ blowfish_decrypt (const struct blowfish_ctx *ctx, d1 = READ_UINT32(src); d2 = READ_UINT32(src+4); - decrypt (ctx, &d1, &d2); + decround (ctx, &d1, &d2); dst[0] = (d1 >> 24) & 0xff; dst[1] = (d1 >> 16) & 0xff; dst[2] = (d1 >> 8) & 0xff; @@ -380,7 +381,7 @@ blowfish_set_key (struct blowfish_ctx *ctx, int i, j; uint32_t data, datal, datar; - *ctx = initial_ctx; + *ctx = _nettle_blowfish_initial_ctx; for (i = j = 0; i < _BLOWFISH_ROUNDS + 2; i++) { @@ -393,15 +394,15 @@ blowfish_set_key (struct blowfish_ctx *ctx, datal = datar = 0; for (i = 0; i < _BLOWFISH_ROUNDS + 2; i += 2) { - encrypt (ctx, &datal, &datar); + _nettle_blowfish_encround (ctx, &datal, &datar); ctx->p[i] = datal; ctx->p[i + 1] = datar; } - + for (j = 0; j < 4; j++) for (i = 0; i < 256; i += 2) { - encrypt (ctx, &datal, &datar); + _nettle_blowfish_encround (ctx, &datal, &datar); ctx->s[j][i] = datal; ctx->s[j][i + 1] = datar; } diff --git a/blowfish.h b/blowfish.h index bcdc7cb6..af48e20f 100644 --- a/blowfish.h +++ b/blowfish.h @@ -46,6 +46,8 @@ extern "C" { #define blowfish128_set_key nettle_blowfish128_set_key #define blowfish_encrypt nettle_blowfish_encrypt #define blowfish_decrypt nettle_blowfish_decrypt +#define blowfish_bcrypt_hash nettle_blowfish_bcrypt_hash +#define blowfish_bcrypt_verify nettle_blowfish_bcrypt_verify #define BLOWFISH_BLOCK_SIZE 8 @@ -60,6 +62,9 @@ extern "C" { #define _BLOWFISH_ROUNDS 16 +#define BLOWFISH_BCRYPT_HASH_SIZE (60 + 1) /* Including null-terminator */ +#define BLOWFISH_BCRYPT_BINSALT_SIZE 16 /* Binary string size */ + struct blowfish_ctx { uint32_t s[4][256]; @@ -81,6 +86,16 @@ void blowfish_decrypt(const struct blowfish_ctx *ctx, size_t length, uint8_t *dst, const uint8_t *src); +int +blowfish_bcrypt_hash(size_t length, + char *dst, + const char *key, + const char *scheme, + int log2rounds, + const uint8_t *salt); +int +blowfish_bcrypt_verify(const char *key, + const char *hashed); #ifdef __cplusplus } diff --git a/nettle.texinfo b/nettle.texinfo index ff64889c..13b1df39 100644 --- a/nettle.texinfo +++ b/nettle.texinfo @@ -1512,6 +1512,73 @@ in any other way. Analogous to @code{blowfish_encrypt} @end deftypefun +@deftypefun int blowfish_bcrypt_hash (size_t @var{length}, char *@var{dst}, const char *@var{key}, const char *@var{scheme}, int @var{log2rounds}, const uint8_t *@var{salt}) +Compute the bcrypt password hash. +The function will return @code{0} if the hash cannot be computed +due to invalid input. +The function will return @code{1} and store the computed hash +in the array pointed to by @var{dst}. The hash is computed based +on the chosen @var{scheme}, number of rounds @var{log2rounds} and +specified @var{salt}. + +@var{length} must be at least @code{BLOWFISH_BCRYPT_HASH_SIZE}. + +@var{dst} must point to a character array of the specified @var{length}. + +@var{key} contains the zero terminated plaintext password string. + +@var{scheme} contains either just the chosen scheme (valid schemes +are: @code{2a}, @code{2b}, @code{2x} or @code{2y}), or +(the prefix of) an existing hashed password (typically @code{$2b$10$...}). + +@var{log2rounds} contains the log2 of the number of encryption rounds +that must be used to compute the hash. If it is @code{-1} the value +will be extracted from @var{scheme}. + +@var{salt} should point to an array of @code{BLOWFISH_BCRYPT_BINSALT_SIZE} +random bytes to be used to perturb the hash computation. If it is @code{NULL} +the salt will be extracted from @var{scheme}. + +Sample code to generate a bcrypt hash: +@example +char cleartxtpassword[] = "ExamplePassword"; +uint8_t salt[BLOWFISH_BCRYPT_BINSALT_SIZE]; +@dots{} +/* Make sure that salt is filled with random bytes */ +@dots{} +char hashedresult[BLOWFISH_BCRYPT_HASH_SIZE]; +int result = blowfish_bcrypt(sizeof(hashedresult), hashedresult, + cleartxtpassword, "2b", 10, salt); +if (result) + printf("%s\n", hashedresult); +@end example +@end deftypefun + +@deftypefun int blowfish_bcrypt_verify (const char *@var{key}, const char *@var{hashed}) +Verifies the bcrypt password hash against the supplied plaintext password. +The function will return @code{0} if the password does not match. +The function will return @code{1} if the password matches. + +@var{key} contains the zero terminated plaintext password string. + +@var{hashed} contains the zero terminated hashed string to compare with. + +Sample code to verify a bcrypt hash: +@example +char cleartxtpassword[] = "ExamplePassword"; +char existinghashed[] = + "$2y$" /* Hash algorithm version */ + "10" /* 2^10 hash rounds (strength) */ + "$" /* separator */ + "1b2lPgo4XumibnJGN3r3sO" /* base64 encoded 16-byte salt */ + "u7wE7xNfYDKlAxZffJDCJdVfFTAyevu"; /* Hashedpart */ +if (blowfish_bcrypt_verify(cleartxtpassword, existinghashed)) + printf("Password is correct."); +else + printf("Password is incorrect."); +@end example +@end deftypefun + @subsection Camellia @cindex Camellia -- 2.20.1

3 5

Failure of gnutls ci build
by nisse＠lysator.liu.se 03 Apr '20

03 Apr '20

Hi, I committed a change to update nettle version numbers, which implies a new symbol version for internal symbols. That seems to break the gnutls ci build, https://gitlab.com/gnutls/nettle/-/jobs/487360242 The error is 1217 ./bootstrap: getting translations into po/.reference for gnutls... 1218 wget: /lib64/libhogweed.so.5: version `HOGWEED_INTERNAL_5_0' not found (required by /lib64/libgnutls.so.30) 1219 wget: /lib64/libnettle.so.7: version `NETTLE_INTERNAL_7_0' not found (required by /lib64/libgnutls.so.30) I don't quite understand all details. This job buils and installs nettle, as ./configure --disable-documentation --prefix=/usr --libdir=/usr/lib64 && make -j4 && make install replacing any previously instaled version with the same soname. So that's a somewhat broader test than I had expected. That explains why linking of wget is affected. The more worring part is that the installed gnutls library seems to depend on internal nettle symbols (it would have been nice if the error message named the offending symbols). Is that intended? It's not necessarily wrong, but any packaged version of gnutls built that way *must* be marked to depend on exactly the same versions of nettle with which it was built. And the ci rule would need to use a different prefix and some other way to tell the gnutls build to use the newly built nettle library instead of the system version. On my own debian machine I have libgnutls.so.30, but apparently an older version. According to objdump -T /usr/lib/x86_64-linux-gnu/libgnutls.so.30 the version I have refers only to symbols with version NETTLE_6 and HOGWEED_4, i.e., nettle version older than 3.5. And no mention of NETTLE_INTERNAL or HOGWEED_INTERNAL. Regards, /Niels -- Niels Möller. PGP-encrypted email is preferred. Keyid 368C6677. Internet email is subject to wholesale government surveillance.

5 9

Nettle 3.5.1 and OS X 10.12 patch
by Jeffrey Walton 31 Mar '20

31 Mar '20

Hi Everyone/Niels, I've got a bare-bones Mac-mini without Xcode. It has CC Tools but that is it. It is in a stock configuration. When I attempt to run 'make check' nearly every test failed due to missing libnettle and libhogweed. The libraries were present in .lib/, but something was blowing away LD_LIBRARY_PATH and DYLD_LIBRARY_PATH. My driver script set it, and the Nettle sources also set it after I set it. But by the times the test runner scripts were run, they were empty again (they were empty at the Makefile, before hitting the test runners). I know Apple did some hardening lately but I have not read anything about scrubbing LD_LIBRARY_PATH and DYLD_LIBRARY_PATH. But it appears something was sanitizing the environment. Attached is the patch I needed for the issue on OS X 10.12. It also tested good on Ubuntu 18.04 and Solaris 11.3. Earlier versions of OS X, like OS X 10.9 and OS X 10.5, were OK. It was just OS X 10.12. The short of it is, each test runner, like run-tests.sh, needed to restore the variables using an absolute path. dirname is Posix so it is available to strip the unwanted path component, like testsuite/ or example/. +nettle_lib_dir=`dirname $PWD`/.lib +LD_LIBRARY_PATH=$nettle_lib_dir +DYLD_LIBRARY_PATH=$nettle_lib_dir + +export LD_LIBRARY_PATH +export DYLD_LIBRARY_PATH Jeff

3 13

Failure of gnutls ci build
by nisse＠lysator.liu.se 29 Mar '20

29 Mar '20

Hi, I committed a change to update nettle version numbers, which implies a new symbol version for internal symbols. That seems to break the gnutls ci build, https://gitlab.com/gnutls/nettle/-/jobs/487360242 The error is 1217 ./bootstrap: getting translations into po/.reference for gnutls... 1218 wget: /lib64/libhogweed.so.5: version `HOGWEED_INTERNAL_5_0' not found (required by /lib64/libgnutls.so.30) 1219 wget: /lib64/libnettle.so.7: version `NETTLE_INTERNAL_7_0' not found (required by /lib64/libgnutls.so.30) I don't quite understand all details. This job buils and installs nettle, as ./configure --disable-documentation --prefix=/usr --libdir=/usr/lib64 && make -j4 && make install replacing any previously installed version with the same soname. So that's a somewhat broader test than I had expected. That explains why linking of wget is affected. The more worring part is that the installed gnutls library seems to depend on internal nettle symbols (it would have been nice if the error message named the offending symbols). Is that intended? It's not necessarily wrong, but any packaged version of gnutls built that way *must* be marked to depend on exactly the same versions of nettle with which it was built. And the ci rule would need to use a different prefix and some other way to tell the gnutls build to use the newly built nettle library instead of the system version. On my own debian machine I have libgnutls.so.30, but apparently an older version. According to objdump -T /usr/lib/x86_64-linux-gnu/libgnutls.so.30 the version I have refers only to symbols with version NETTLE_6 and HOGWEED_4, i.e., nettle version older than 3.5. And no mention of NETTLE_INTERNAL or HOGWEED_INTERNAL. Regards, /Niels -- Niels Möller. PGP-encrypted email is preferred. Keyid 368C6677. Internet email is subject to wholesale government surveillance.

1 0

Failure of gnutls ci build
by nisse＠lysator.liu.se 28 Mar '20

28 Mar '20

Hi, I committed a change to update nettle version numbers, which implies a new symbol version for internal symbols. That seems to break the gnutls ci build, https://gitlab.com/gnutls/nettle/-/jobs/487360242 The error is 1217 ./bootstrap: getting translations into po/.reference for gnutls... 1218 wget: /lib64/libhogweed.so.5: version `HOGWEED_INTERNAL_5_0' not found (required by /lib64/libgnutls.so.30) 1219 wget: /lib64/libnettle.so.7: version `NETTLE_INTERNAL_7_0' not found (required by /lib64/libgnutls.so.30) I don't quite understand all details. This job buils and installs nettle, as ./configure --disable-documentation --prefix=/usr --libdir=/usr/lib64 && make -j4 && make install replacing any previously installed version with the same soname. So that's a somewhat broader test than I had expected. That explains why linking of wget is affected. The more worring part is that the installed gnutls library seems to depend on internal nettle symbols (it would have been nice if the error message named the offending symbols). Is that intended? It's not necessarily wrong, but any packaged version of gnutls built that way *must* be marked to depend on exactly the same versions of nettle with which it was built. And the ci rule would need to use a different prefix and some other way to tell the gnutls build to use the newly built nettle library instead of the system version. On my own debian machine I have libgnutls.so.30, but apparently an older version. According to objdump -T /usr/lib/x86_64-linux-gnu/libgnutls.so.30 the version I have refers only to symbols with version NETTLE_6 and HOGWEED_4, i.e., nettle version older than 3.5. And no mention of NETTLE_INTERNAL or HOGWEED_INTERNAL. Regards, /Niels -- Niels Möller. PGP-encrypted email is preferred. Keyid 368C6677. Internet email is subject to wholesale government surveillance.

1 0

[PATCH] (revision 3.0) Added bcrypt() support.
by Stephen R. van den Berg 23 Mar '20

23 Mar '20

--- Makefile.in | 2 +- base64-decode.c | 17 +- blowfish-bcrypt.c | 531 ++++++++++++++++++++++++++++++ blowfish.h => blowfish-internal.h | 51 +-- blowfish.c | 23 +- blowfish.h | 15 + nettle.texinfo | 67 ++++ 7 files changed, 640 insertions(+), 66 deletions(-) create mode 100644 blowfish-bcrypt.c copy blowfish.h => blowfish-internal.h (50%) diff --git a/Makefile.in b/Makefile.in index ddc30428..bfb7ac57 100644 --- a/Makefile.in +++ b/Makefile.in @@ -73,7 +73,7 @@ nettle_SOURCES = aes-decrypt-internal.c aes-decrypt.c \ aes256-set-encrypt-key.c aes256-set-decrypt-key.c \ aes256-meta.c \ arcfour.c arcfour-crypt.c \ - arctwo.c arctwo-meta.c blowfish.c \ + arctwo.c arctwo-meta.c blowfish.c blowfish-bcrypt.c \ base16-encode.c base16-decode.c base16-meta.c \ base64-encode.c base64-decode.c base64-meta.c \ base64url-encode.c base64url-decode.c base64url-meta.c \ diff --git a/base64-decode.c b/base64-decode.c index b993117a..9273224a 100644 --- a/base64-decode.c +++ b/base64-decode.c @@ -45,7 +45,7 @@ void base64_decode_init(struct base64_decode_ctx *ctx) { - static const signed char base64_decode_table[0x100] = + static const signed char base64_decode_table[0x80] = { /* White space is HT, VT, FF, CR, LF and SPC */ -1, -1, -1, -1, -1, -1, -1, -1, -1, -2, -2, -2, -2, -2, -1, -1, @@ -56,14 +56,6 @@ base64_decode_init(struct base64_decode_ctx *ctx) 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -1, -1, -1, -1, -1, -1, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, -1, -1, -1, -1, -1, - -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, - -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, - -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, - -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, - -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, - -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, - -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, - -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, }; ctx->word = ctx->bits = ctx->padding = 0; @@ -75,7 +67,12 @@ base64_decode_single(struct base64_decode_ctx *ctx, uint8_t *dst, char src) { - int data = ctx->table[(uint8_t) src]; + int data; + + if ((uint8_t) src > 0x7f) + return -1; + + data = ctx->table[(uint8_t) src]; switch(data) { diff --git a/blowfish-bcrypt.c b/blowfish-bcrypt.c new file mode 100644 index 00000000..60bbd090 --- /dev/null +++ b/blowfish-bcrypt.c @@ -0,0 +1,531 @@ +/* blowfish-bcrypt.c + + The blowfish bcrypt implementation. + + Copyright (c) 2020 Stephen R. van den Berg + + This file is part of GNU Nettle. + + GNU Nettle is free software: you can redistribute it and/or + modify it under the terms of either: + + * the GNU Lesser General Public License as published by the Free + Software Foundation; either version 3 of the License, or (at your + option) any later version. + + or + + * the GNU General Public License as published by the Free + Software Foundation; either version 2 of the License, or (at your + option) any later version. + + or both in parallel, as here. + + GNU Nettle is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + General Public License for more details. + + You should have received copies of the GNU General Public License and + the GNU Lesser General Public License along with this program. If + not, see http://www.gnu.org/licenses/. +*/ + +#if HAVE_CONFIG_H +#include "config.h" +#endif + +#include <assert.h> +#include <string.h> +#include <stdlib.h> + +#include "blowfish.h" +#include "blowfish-internal.h" +#include "base64.h" + +#include "macros.h" + +#define CRYPTPLEN 7 +#define SALTLEN ((BLOWFISH_BCRYPT_BINSALT_SIZE*8+5) / 6) + +#define HASHOFFSET (CRYPTPLEN + SALTLEN) + +static const signed char radix64_decode_table[0x80] = { + /* White space is HT, VT, FF, CR, LF and SPC */ + -1, -1, -1, -1, -1, -1, -1, -1, -1, -2, -2, -2, -2, -2, -1, -1, + -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, + -2, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 0, 1, + 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, -1, -1, -1, -3, -1, -1, + -1, 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, -1, -1, -1, -1, -1, + -1, 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, -1, -1, -1, -1, -1, +}; + +static const char radix64_encode_table[64] = + "./ABCDEFGHIJKLMNOPQRSTUVWXYZ" + "abcdefghijklmnopqrstuvwxyz" + "0123456789"; + +int +blowfish_bcrypt_verify(const char *key, + const char *hashed) +{ + char newhash[BLOWFISH_BCRYPT_HASH_SIZE]; + + return blowfish_bcrypt_hash(sizeof newhash, + newhash, key, hashed, -1, (void*)0) + && !strcmp(newhash, hashed); +} + +static char *encode_radix64(char *dst, size_t len, const uint8_t *src) +{ + struct base64_encode_ctx ctx; + base64_encode_init(&ctx); + ctx.alphabet = radix64_encode_table; + dst += base64_encode_update(&ctx, dst, len, src); + dst += base64_encode_final(&ctx, dst); + *--dst = '\0'; /* Strip the trailing = */ + return dst; +} + +/* + * Large parts of the code below are based on public domain sources. + * The comments and copyright notices have been preserved. + * Any code added or modified by me is licensed under the + * licenses listed above. -- Stephen R. van den Berg + */ + +/* + * This code comes from John the Ripper password cracker, with reentrant + * and crypt(3) interfaces added, but optimizations specific to password + * cracking removed. + * + * Written by Solar Designer <solar at openwall.com> in 1998-2015. + * No copyright is claimed, and the software is hereby placed in the public + * domain. In case this attempt to disclaim copyright and place the software + * in the public domain is deemed null and void, then the software is + * Copyright (c) 1998-2015 Solar Designer and it is hereby released to the + * general public under the following terms: + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted. + * + * There's ABSOLUTELY NO WARRANTY, express or implied. + * + * It is my intent that you should be able to use this on your system, + * as part of a software package, or anywhere else to improve security, + * ensure compatibility, or for any other purpose. I would appreciate + * it if you give credit where it is due and keep your modifications in + * the public domain as well, but I don't require that in order to let + * you place this code and any modifications you make under a license + * of your choice. + * + * This implementation is fully compatible with OpenBSD's bcrypt.c for prefix + * "$2b$", originally by Niels Provos <provos at citi.umich.edu>, and it uses + * some of his ideas. The password hashing algorithm was designed by David + * Mazieres <dm at lcs.mit.edu>. For information on the level of + * compatibility for bcrypt hash prefixes other than "$2b$", please refer to + * the comments in set_key() below and to the included crypt(3) man page. + */ + +typedef uint32_t bf_key[_BLOWFISH_ROUNDS + 2]; + +/* + * Magic IV for 64 Blowfish encryptions that we do at the end. + * The string is "OrpheanBeholderScryDoubt" on big-endian. + */ +static uint32_t magic_w[6] = { + 0x4F727068, 0x65616E42, 0x65686F6C, + 0x64657253, 0x63727944, 0x6F756274 +}; + +static void swap32(uint32_t *x, int count) +{ +#if !WORDS_BIGENDIAN + do { + uint32_t tmp = *x; + tmp = (tmp << 16) | (tmp >> 16); + *x++ = ((tmp & 0x00FF00FF) << 8) | ((tmp >> 8) & 0x00FF00FF); + } while (--count); +#endif +} + +static void set_xkey(const char *key, bf_key expanded, bf_key initial, + unsigned bug, uint32_t safety) +{ + const char *ptr = key; + unsigned i, j; + uint32_t sign, diff, tmp[2]; + +/* + * There was a sign extension bug in older revisions of this function. While + * we would have liked to simply fix the bug and move on, we have to provide + * a backwards compatibility feature (essentially the bug) for some systems and + * a safety measure for some others. The latter is needed because for certain + * multiple inputs to the buggy algorithm there exist easily found inputs to + * the correct algorithm that produce the same hash. Thus, we optionally + * deviate from the correct algorithm just enough to avoid such collisions. + * While the bug itself affected the majority of passwords containing + * characters with the 8th bit set (although only a percentage of those in a + * collision-producing way), the anti-collision safety measure affects + * only a subset of passwords containing the '\xff' character (not even all of + * those passwords, just some of them). This character is not found in valid + * UTF-8 sequences and is rarely used in popular 8-bit character encodings. + * Thus, the safety measure is unlikely to cause much annoyance, and is a + * reasonable tradeoff to use when authenticating against existing hashes that + * are not reliably known to have been computed with the correct algorithm. + * + * We use an approach that tries to minimize side-channel leaks of password + * information - that is, we mostly use fixed-cost bitwise operations instead + * of branches or table lookups. (One conditional branch based on password + * length remains. It is not part of the bug aftermath, though, and is + * difficult and possibly unreasonable to avoid given the use of C strings by + * the caller, which results in similar timing leaks anyway.) + * + * For actual implementation, we set an array index in the variable "bug" + * (0 means no bug, 1 means sign extension bug emulation) and a flag in the + * variable "safety" (bit 16 is set when the safety measure is requested). + * Valid combinations of settings are: + * + * Prefix "$2a$": bug = 0, safety = 0x10000 + * Prefix "$2b$": bug = 0, safety = 0 + * Prefix "$2x$": bug = 1, safety = 0 + * Prefix "$2y$": bug = 0, safety = 0 + */ + + sign = diff = 0; + + for (i = 0; i < _BLOWFISH_ROUNDS + 2; i++) { + tmp[0] = tmp[1] = 0; + for (j = 0; j < 4; j++) { + tmp[0] <<= 8; + tmp[0] |= (unsigned char)*ptr; /* correct */ + tmp[1] <<= 8; + tmp[1] |= (signed char)*ptr; /* bug */ +/* + * Sign extension in the first char has no effect - nothing to overwrite yet, + * and those extra 24 bits will be fully shifted out of the 32-bit word. For + * chars 2, 3, 4 in each four-char block, we set bit 7 of "sign" if sign + * extension in tmp[1] occurs. Once this flag is set, it remains set. + */ + if (j) + sign |= tmp[1] & 0x80; + if (!*ptr) + ptr = key; + else + ptr++; + } + diff |= tmp[0] ^ tmp[1]; /* Non-zero on any differences */ + + expanded[i] = tmp[bug]; + initial[i] = _nettle_blowfish_initial_ctx.p[i] ^ tmp[bug]; + } + +/* + * At this point, "diff" is zero if the correct and buggy algorithms produced + * exactly the same result. If so and if "sign" is non-zero, which indicates + * that there was a non-benign sign extension, this means that we have a + * collision between the correctly computed hash for this password and a set of + * passwords that could be supplied to the buggy algorithm. Our safety measure + * is meant to protect from such many-buggy to one-correct collisions, by + * deviating from the correct algorithm in such cases. Let's check for this. + */ + diff |= diff >> 16; /* still zero if exact match */ + diff &= 0xffff; /* ditto */ + diff += 0xffff; /* bit 16 set if "diff" was non-zero (on non-match) */ + sign <<= 9; /* move the non-benign sign extension flag to bit 16 */ + sign &= ~diff & safety; /* action needed? */ + +/* + * If we have determined that we need to deviate from the correct algorithm, + * flip bit 16 in initial expanded key. (The choice of 16 is arbitrary, but + * let's stick to it now. It came out of the approach we used above, and it's + * not any worse than any other choice we could make.) + * + * It is crucial that we don't do the same to the expanded key used in the main + * Eksblowfish loop. By doing it to only one of these two, we deviate from a + * state that could be directly specified by a password to the buggy algorithm + * (and to the fully correct one as well, but that's a side-effect). + */ + initial[0] ^= sign; +} + +static int ibcrypt(size_t length, char *dst, + const char *key, const char *scheme, + int minlog2rounds, + int log2rounds, const uint8_t *salt) +{ + struct { + struct blowfish_ctx ctx; + bf_key expanded_key; + union { + uint32_t salt[4]; + uint32_t output[6]; + } binary; + } data; + uint8_t psalt[BLOWFISH_BCRYPT_BINSALT_SIZE]; + uint32_t L, R; + uint32_t *ptr; + uint32_t count; + int i; + size_t schemelen = strlen(scheme); + unsigned cscheme; + unsigned bug = 0; + uint32_t safety = 0; + if (length < BLOWFISH_BCRYPT_HASH_SIZE || + schemelen < 2) + return 0; + + if (schemelen >= 3 && *scheme++ != '$') + return 0; + if (*scheme++ != '2') + return 0; + + switch (cscheme = *scheme++) { + default: + return 0; + case 'a': safety = 0x10000; + break; + case 'x': bug = 1; + break; + case 'b': case 'y': + break; + } + + if (schemelen >= 4) { + if (*scheme++ != '$') + return 0; + if (schemelen >= 6) { + if (log2rounds < 0) + log2rounds = atoi(scheme); + scheme += 2; + if (schemelen >= CRYPTPLEN && *scheme++ != '$') + return 0; + if (schemelen >= HASHOFFSET && !salt) { + struct base64_decode_ctx ctx; + size_t saltlen = BLOWFISH_BCRYPT_BINSALT_SIZE; + + base64_decode_init(&ctx); + ctx.table = radix64_decode_table; + + if (!base64_decode_update(&ctx, &saltlen, (uint8_t *) data.binary.salt, + SALTLEN, scheme) + || saltlen != BLOWFISH_BCRYPT_BINSALT_SIZE) + return 0; + } + } + } + + if (salt) + memcpy(data.binary.salt, salt, BLOWFISH_BCRYPT_BINSALT_SIZE); + else if (schemelen < HASHOFFSET) + return 0; + memcpy(psalt, data.binary.salt, BLOWFISH_BCRYPT_BINSALT_SIZE); + swap32(data.binary.salt, 4); + + if (log2rounds < minlog2rounds || log2rounds > 31) + return 0; + count = (uint32_t)1 << log2rounds; + + set_xkey(key, data.expanded_key, data.ctx.p, bug, safety); + memcpy(data.ctx.s, _nettle_blowfish_initial_ctx.s, sizeof(data.ctx.s)); + + L = R = 0; + for (i = 0; i < _BLOWFISH_ROUNDS + 2; i += 2) { + L ^= data.binary.salt[i & 2]; + R ^= data.binary.salt[(i & 2) + 1]; + _nettle_blowfish_encround(&data.ctx, &L, &R); + data.ctx.p[i] = L; + data.ctx.p[i + 1] = R; + } + + ptr = data.ctx.s[0]; + do { + ptr += 4; + L ^= data.binary.salt[(_BLOWFISH_ROUNDS + 2) & 3]; + R ^= data.binary.salt[(_BLOWFISH_ROUNDS + 3) & 3]; + _nettle_blowfish_encround(&data.ctx, &L, &R); + *(ptr - 4) = L; + *(ptr - 3) = R; + + L ^= data.binary.salt[(_BLOWFISH_ROUNDS + 4) & 3]; + R ^= data.binary.salt[(_BLOWFISH_ROUNDS + 5) & 3]; + _nettle_blowfish_encround(&data.ctx, &L, &R); + *(ptr - 2) = L; + *(ptr - 1) = R; + } while (ptr < &data.ctx.s[3][0xFF]); + + do { + int done; + + for (i = 0; i < _BLOWFISH_ROUNDS + 2; i += 2) { + data.ctx.p[i] ^= data.expanded_key[i]; + data.ctx.p[i + 1] ^= data.expanded_key[i + 1]; + } + + done = 0; + do { + uint32_t tmp1, tmp2, tmp3, tmp4; + + L = R = 0; + ptr = data.ctx.p; + do { + ptr += 2; + _nettle_blowfish_encround(&data.ctx, &L, &R); + *(ptr - 2) = L; + *(ptr - 1) = R; + } while (ptr < &data.ctx.p[_BLOWFISH_ROUNDS + 2]); + + ptr = data.ctx.s[0]; + do { + ptr += 2; + _nettle_blowfish_encround(&data.ctx, &L, &R); + *(ptr - 2) = L; + *(ptr - 1) = R; + } while (ptr < &data.ctx.s[3][0xFF]); + + if (done) + break; + done = 1; + + tmp1 = data.binary.salt[0]; + tmp2 = data.binary.salt[1]; + tmp3 = data.binary.salt[2]; + tmp4 = data.binary.salt[3]; + for (i = 0; i < _BLOWFISH_ROUNDS; i += 4) { + data.ctx.p[i] ^= tmp1; + data.ctx.p[i + 1] ^= tmp2; + data.ctx.p[i + 2] ^= tmp3; + data.ctx.p[i + 3] ^= tmp4; + } + data.ctx.p[16] ^= tmp1; + data.ctx.p[17] ^= tmp2; + } while (1); + } while (--count); + + for (i = 0; i < 6; i += 2) { + L = magic_w[i]; + R = magic_w[i + 1]; + + count = 64; + do + _nettle_blowfish_encround(&data.ctx, &L, &R); + while (--count); + + data.binary.output[i] = L; + data.binary.output[i + 1] = R; + } + + *dst++ = '$'; + *dst++ = '2'; + *dst++ = cscheme; + *dst++ = '$'; + *dst++ = '0' + log2rounds / 10; + *dst++ = '0' + log2rounds % 10; + *dst++ = '$'; + dst = encode_radix64(dst, BLOWFISH_BCRYPT_BINSALT_SIZE, psalt) - 1; + + swap32(data.binary.output, 6); +/* This has to be bug-compatible with the original implementation, so + only encode 23 of the 24 bytes. */ + encode_radix64(dst, 23, (uint8_t *) data.binary.output); + return cscheme; +} + +static +int bcrypt_output_magic(const char *settings, char *output, int size) +{ + if (size < 3) + return -1; + + output[0] = '*'; + output[1] = '0'; + output[2] = '\0'; + + if (settings[0] == '*' && settings[1] == '0') + output[1] = '1'; + + return 0; +} + +/* + * Please preserve the runtime self-test. It serves two purposes at once: + * + * 1. We really can't afford the risk of producing incompatible hashes e.g. + * when there's something like gcc bug 26587 again, whereas an application or + * library integrating this code might not also integrate our external tests or + * it might not run them after every build. Even if it does, the miscompile + * might only occur on the production build, but not on a testing build (such + * as because of different optimization settings). It is painful to recover + * from incorrectly-computed hashes - merely fixing whatever broke is not + * enough. Thus, a proactive measure like this self-test is needed. + * + * 2. We don't want to leave sensitive data from our actual password hash + * computation on the stack or in registers. Previous revisions of the code + * would do explicit cleanups, but simply running the self-test after hash + * computation is more reliable. + * + * The performance cost of this quick self-test is around 0.6% at the "$2a$08" + * setting. + */ +int blowfish_bcrypt_hash(size_t length, char *dst, + const char *key, const char *scheme, + int log2rounds, const uint8_t *salt) +{ + const char *test_pw = "8b \xd0\xc1\xd2\xcf\xcc\xd8"; + const char *test_scheme = "$2a$00$abcdefghijklmnopqrstuu"; + static const char * const test_hashes[2] = + {"i1D709vfamulimlGcq0qq3UvuUasvEa\0\x55", /* 'a', 'b', 'y' */ + "VUrPmXD6q/nVSSp7pNDhCR9071IfIRe\0\x55"}; /* 'x' */ + const char *test_hash = test_hashes[0]; + int cscheme; + int ok; + struct { + char s[HASHOFFSET + 1]; + char o[HASHOFFSET + 31 + 1 + 1 + 1]; + } buf; + +/* Hash the supplied password */ + bcrypt_output_magic(scheme, dst, length); + cscheme = ibcrypt(length, dst, key, scheme, 4, log2rounds, salt); + +/* + * Do a quick self-test. It is important that we make both calls to ibcrypt() + * from the same scope such that they likely use the same stack locations, + * which makes the second call overwrite the first call's sensitive data on the + * stack and makes it more likely that any alignment related issues would be + * detected by the self-test. + */ + memcpy(buf.s, test_scheme, sizeof(buf.s)); + + if (cscheme) + test_hash = test_hashes[(buf.s[2] = cscheme) == 'x']; + + memset(buf.o, 0x55, sizeof(buf.o)); + buf.o[sizeof(buf.o) - 1] = 0; + ok = ibcrypt(sizeof(buf.o) - (1 + 1), buf.o, test_pw, + buf.s, 0, -1, (void*)0); + + ok = (ok && + !memcmp(buf.o, buf.s, HASHOFFSET) && + !memcmp(buf.o + HASHOFFSET, test_hash, 31 + 1 + 1 + 1)); + + { + const char *k = "\xff\xa3" "34" "\xff\xff\xff\xa3" "345"; + bf_key ae, ai, ye, yi; + set_xkey(k, ae, ai, 0, 0x10000); /* $2a$ */ + set_xkey(k, ye, yi, 0, 0); /* $2y$ */ + ai[0] ^= 0x10000; /* undo the safety (for comparison) */ + ok = ok && ai[0] == 0xdb9c59bc && ye[17] == 0x33343500 && + !memcmp(ae, ye, sizeof(ae)) && + !memcmp(ai, yi, sizeof(ai)); + } + + if (ok) + return !!cscheme; + +/* Should not happen */ + bcrypt_output_magic(scheme, dst, length); + return 0; +} diff --git a/blowfish.h b/blowfish-internal.h similarity index 50% copy from blowfish.h copy to blowfish-internal.h index bcdc7cb6..da28fa34 100644 --- a/blowfish.h +++ b/blowfish-internal.h @@ -1,4 +1,4 @@ -/* blowfish.h +/* blowfish-internal.h Blowfish block cipher. @@ -32,8 +32,8 @@ not, see http://www.gnu.org/licenses/. */ -#ifndef NETTLE_BLOWFISH_H_INCLUDED -#define NETTLE_BLOWFISH_H_INCLUDED +#ifndef NETTLE_BLOWFISH_INTERNAL_H_INCLUDED +#define NETTLE_BLOWFISH_INTERNAL_H_INCLUDED #include "nettle-types.h" @@ -41,49 +41,12 @@ extern "C" { #endif -/* Name mangling */ -#define blowfish_set_key nettle_blowfish_set_key -#define blowfish128_set_key nettle_blowfish128_set_key -#define blowfish_encrypt nettle_blowfish_encrypt -#define blowfish_decrypt nettle_blowfish_decrypt - -#define BLOWFISH_BLOCK_SIZE 8 - -/* Variable key size between 64 and 448 bits. */ -#define BLOWFISH_MIN_KEY_SIZE 8 -#define BLOWFISH_MAX_KEY_SIZE 56 - -/* Default to 128 bits */ -#define BLOWFISH_KEY_SIZE 16 - -#define BLOWFISH128_KEY_SIZE 16 - -#define _BLOWFISH_ROUNDS 16 - -struct blowfish_ctx -{ - uint32_t s[4][256]; - uint32_t p[_BLOWFISH_ROUNDS+2]; -}; - -/* Returns 0 for weak keys, otherwise 1. */ -int -blowfish_set_key(struct blowfish_ctx *ctx, - size_t length, const uint8_t *key); -int -blowfish128_set_key(struct blowfish_ctx *ctx, const uint8_t *key); - -void -blowfish_encrypt(const struct blowfish_ctx *ctx, - size_t length, uint8_t *dst, - const uint8_t *src); -void -blowfish_decrypt(const struct blowfish_ctx *ctx, - size_t length, uint8_t *dst, - const uint8_t *src); +extern const struct blowfish_ctx _nettle_blowfish_initial_ctx; +extern void _nettle_blowfish_encround (const struct blowfish_ctx *ctx, + uint32_t * ret_xl, uint32_t * ret_xr); #ifdef __cplusplus } #endif -#endif /* NETTLE_BLOWFISH_H_INCLUDED */ +#endif /* NETTLE_BLOWFISH_INTERNAL_H_INCLUDED */ diff --git a/blowfish.c b/blowfish.c index 52040f13..e73caffe 100644 --- a/blowfish.c +++ b/blowfish.c @@ -54,12 +54,13 @@ #include <assert.h> #include "blowfish.h" +#include "blowfish-internal.h" #include "macros.h" /* precomputed S boxes */ -static const struct blowfish_ctx -initial_ctx = { +const struct blowfish_ctx +_nettle_blowfish_initial_ctx = { { { /* ks0 */ 0xD1310BA6, 0x98DFB5AC, 0x2FFD72DB, 0xD01ADFB7, 0xB8E1AFED, 0x6A267E96, @@ -261,8 +262,8 @@ initial_ctx = { #define R(c, l,r,i) do { l ^= c->p[i]; r ^= F(c,l); } while(0) -static void -encrypt (const struct blowfish_ctx *ctx, uint32_t * ret_xl, +void +_nettle_blowfish_encround (const struct blowfish_ctx *ctx, uint32_t * ret_xl, uint32_t * ret_xr) { uint32_t xl, xr; @@ -295,7 +296,7 @@ encrypt (const struct blowfish_ctx *ctx, uint32_t * ret_xl, } static void -decrypt (const struct blowfish_ctx *ctx, uint32_t * ret_xl, uint32_t * ret_xr) +decround (const struct blowfish_ctx *ctx, uint32_t * ret_xl, uint32_t * ret_xr) { uint32_t xl, xr; @@ -339,7 +340,7 @@ blowfish_encrypt (const struct blowfish_ctx *ctx, d1 = READ_UINT32(src); d2 = READ_UINT32(src+4); - encrypt (ctx, &d1, &d2); + _nettle_blowfish_encround (ctx, &d1, &d2); dst[0] = (d1 >> 24) & 0xff; dst[1] = (d1 >> 16) & 0xff; dst[2] = (d1 >> 8) & 0xff; @@ -361,7 +362,7 @@ blowfish_decrypt (const struct blowfish_ctx *ctx, d1 = READ_UINT32(src); d2 = READ_UINT32(src+4); - decrypt (ctx, &d1, &d2); + decround (ctx, &d1, &d2); dst[0] = (d1 >> 24) & 0xff; dst[1] = (d1 >> 16) & 0xff; dst[2] = (d1 >> 8) & 0xff; @@ -380,7 +381,7 @@ blowfish_set_key (struct blowfish_ctx *ctx, int i, j; uint32_t data, datal, datar; - *ctx = initial_ctx; + *ctx = _nettle_blowfish_initial_ctx; for (i = j = 0; i < _BLOWFISH_ROUNDS + 2; i++) { @@ -393,15 +394,15 @@ blowfish_set_key (struct blowfish_ctx *ctx, datal = datar = 0; for (i = 0; i < _BLOWFISH_ROUNDS + 2; i += 2) { - encrypt (ctx, &datal, &datar); + _nettle_blowfish_encround (ctx, &datal, &datar); ctx->p[i] = datal; ctx->p[i + 1] = datar; } - + for (j = 0; j < 4; j++) for (i = 0; i < 256; i += 2) { - encrypt (ctx, &datal, &datar); + _nettle_blowfish_encround (ctx, &datal, &datar); ctx->s[j][i] = datal; ctx->s[j][i + 1] = datar; } diff --git a/blowfish.h b/blowfish.h index bcdc7cb6..af48e20f 100644 --- a/blowfish.h +++ b/blowfish.h @@ -46,6 +46,8 @@ extern "C" { #define blowfish128_set_key nettle_blowfish128_set_key #define blowfish_encrypt nettle_blowfish_encrypt #define blowfish_decrypt nettle_blowfish_decrypt +#define blowfish_bcrypt_hash nettle_blowfish_bcrypt_hash +#define blowfish_bcrypt_verify nettle_blowfish_bcrypt_verify #define BLOWFISH_BLOCK_SIZE 8 @@ -60,6 +62,9 @@ extern "C" { #define _BLOWFISH_ROUNDS 16 +#define BLOWFISH_BCRYPT_HASH_SIZE (60 + 1) /* Including null-terminator */ +#define BLOWFISH_BCRYPT_BINSALT_SIZE 16 /* Binary string size */ + struct blowfish_ctx { uint32_t s[4][256]; @@ -81,6 +86,16 @@ void blowfish_decrypt(const struct blowfish_ctx *ctx, size_t length, uint8_t *dst, const uint8_t *src); +int +blowfish_bcrypt_hash(size_t length, + char *dst, + const char *key, + const char *scheme, + int log2rounds, + const uint8_t *salt); +int +blowfish_bcrypt_verify(const char *key, + const char *hashed); #ifdef __cplusplus } diff --git a/nettle.texinfo b/nettle.texinfo index ff64889c..13b1df39 100644 --- a/nettle.texinfo +++ b/nettle.texinfo @@ -1512,6 +1512,73 @@ in any other way. Analogous to @code{blowfish_encrypt} @end deftypefun +@deftypefun int blowfish_bcrypt_hash (size_t @var{length}, char *@var{dst}, const char *@var{key}, const char *@var{scheme}, int @var{log2rounds}, const uint8_t *@var{salt}) +Compute the bcrypt password hash. +The function will return @code{0} if the hash cannot be computed +due to invalid input. +The function will return @code{1} and store the computed hash +in the array pointed to by @var{dst}. The hash is computed based +on the chosen @var{scheme}, number of rounds @var{log2rounds} and +specified @var{salt}. + +@var{length} must be at least @code{BLOWFISH_BCRYPT_HASH_SIZE}. + +@var{dst} must point to a character array of the specified @var{length}. + +@var{key} contains the zero terminated plaintext password string. + +@var{scheme} contains either just the chosen scheme (valid schemes +are: @code{2a}, @code{2b}, @code{2x} or @code{2y}), or +(the prefix of) an existing hashed password (typically @code{$2b$10$...}). + +@var{log2rounds} contains the log2 of the number of encryption rounds +that must be used to compute the hash. If it is @code{-1} the value +will be extracted from @var{scheme}. + +@var{salt} should point to an array of @code{BLOWFISH_BCRYPT_BINSALT_SIZE} +random bytes to be used to perturb the hash computation. If it is @code{NULL} +the salt will be extracted from @var{scheme}. + +Sample code to generate a bcrypt hash: +@example +char cleartxtpassword[] = "ExamplePassword"; +uint8_t salt[BLOWFISH_BCRYPT_BINSALT_SIZE]; +@dots{} +/* Make sure that salt is filled with random bytes */ +@dots{} +char hashedresult[BLOWFISH_BCRYPT_HASH_SIZE]; +int result = blowfish_bcrypt(sizeof(hashedresult), hashedresult, + cleartxtpassword, "2b", 10, salt); +if (result) + printf("%s\n", hashedresult); +@end example +@end deftypefun + +@deftypefun int blowfish_bcrypt_verify (const char *@var{key}, const char *@var{hashed}) +Verifies the bcrypt password hash against the supplied plaintext password. +The function will return @code{0} if the password does not match. +The function will return @code{1} if the password matches. + +@var{key} contains the zero terminated plaintext password string. + +@var{hashed} contains the zero terminated hashed string to compare with. + +Sample code to verify a bcrypt hash: +@example +char cleartxtpassword[] = "ExamplePassword"; +char existinghashed[] = + "$2y$" /* Hash algorithm version */ + "10" /* 2^10 hash rounds (strength) */ + "$" /* separator */ + "1b2lPgo4XumibnJGN3r3sO" /* base64 encoded 16-byte salt */ + "u7wE7xNfYDKlAxZffJDCJdVfFTAyevu"; /* Hashedpart */ +if (blowfish_bcrypt_verify(cleartxtpassword, existinghashed)) + printf("Password is correct."); +else + printf("Password is incorrect."); +@end example +@end deftypefun + @subsection Camellia @cindex Camellia -- 2.20.1

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Re: [PATCH] x86: Add x86-ibt-test.c
by nisse＠lysator.liu.se 22 Mar '20

22 Mar '20

"H.J. Lu" <hjl.tools(a)gmail.com> writes: > Here is the updated patch. Pushed to the master-updates branch now. Thanks! Regards, /Niels -- Niels Möller. PGP-encrypted email is preferred. Keyid 368C6677. Internet email is subject to wholesale government surveillance.

1 0

Re: [PATCH] x86: Add x86-ibt-test.c
by nisse＠lysator.liu.se 22 Mar '20

22 Mar '20

"H.J. Lu" <hjl.tools(a)gmail.com> writes: > Here is the updated patch. Thanks! > +#ifdef __i386__ > +static unsigned int > +_get_ssp(void) > +{ > + unsigned int ssp; > + asm volatile("xor %0, %0\n\trdsspd %0" : "=r" (ssp)); > + return ssp; > +} > +#else I take it the rdssp instruction is a nop on older processors? I had a quick look at https://software.intel.com/sites/default/files/managed/4d/2a/control-flow-e… and I don't find any mention of a cpuid bit to check before using this instruction. Regards, /Niels -- Niels Möller. PGP-encrypted email is preferred. Keyid 368C6677. Internet email is subject to wholesale government surveillance.

1 0

Re: [PATCH] x86: Add ibt-test.c
by nisse＠lysator.liu.se 22 Mar '20

22 Mar '20

"H.J. Lu" <hjl.tools(a)gmail.com> writes: > Like this? Yes, thanks! A few comments below. > +AC_CACHE_CHECK([compiler support for -mshstk], > + nettle_cv_x86_mshstk_cflags, > +[AC_TRY_COMPILE([],[int foo], > +nettle_cv_x86_mshstk_cflags=yes, > +nettle_cv_x86_mshstk_cflags=no)]) > +if test "$nettle_cv_x86_mshstk_cflags" = yes; then > + EXTRA_X86_CFLAGS=-mshstk > +fi > +AC_SUBST(EXTRA_X86_CFLAGS) Maybe rename autoconf variable to TESTSUITE_CFLAGS. This check may well be enough, but you could consider limiting it to x86 targets, and having the test program include x86intrin.h and use _get_ssp. > diff --git a/testsuite/.test-rules.make b/testsuite/.test-rules.make > index 922a2c7f..257ce86e 100644 > --- a/testsuite/.test-rules.make > +++ b/testsuite/.test-rules.make > @@ -178,6 +178,9 @@ xts-test$(EXEEXT): xts-test.$(OBJEXT) > pbkdf2-test$(EXEEXT): pbkdf2-test.$(OBJEXT) > $(LINK) pbkdf2-test.$(OBJEXT) $(TEST_OBJS) -o pbkdf2-test$(EXEEXT) > > +ibt-test$(EXEEXT): ibt-test.$(OBJEXT) > + $(LINK) ibt-test.$(OBJEXT) $(TEST_OBJS) -o ibt-test$(EXEEXT) > + Maybe rename x86-ibt-test, if you think this feature is going to be x86 only for the foreseeable future. > diff --git a/testsuite/ibt-test.c b/testsuite/ibt-test.c > new file mode 100644 > index 00000000..fdc97d8f > --- /dev/null > +++ b/testsuite/ibt-test.c > @@ -0,0 +1,43 @@ > +#include "testutils.h" > +#ifdef __CET__ It would make some sense to also check for __GNUC__, __i386__/__x86_64__, and __posix__. Is __CET__ specific enough, or is there a risk that some other compiler or target will use that name with a different meaning? In particular, can it break windows builds? If needed here, same should apply to the configure check from the previous patch. > +#include <signal.h> > +#include <x86intrin.h> > + > +static void > +segfault_handler(int signo) > +{ > + exit(0); > +} > + > +void > +ibt_violation(void) > +{ > +#ifdef __i386__ > + asm volatile("lea 1f, %eax\n\t" > + "jmp *%eax\n" > + "1:"); > +#else > + asm volatile("lea 1f, %rax\n\t" > + "jmp *%rax\n" > + "1:"); > +#endif > +} Nice and easy. I think these need a clobber list to tell gcc that it modifies eax/rax, though. > +void > +test_main(void) > +{ > + /* NB: This test should trigger SIGSEGV on CET platforms. If SHSTK > + is disabled, assuming IBT is also disabled. */ > + if (_get_ssp() == 0) > + SKIP(); I would suggest if (_get_ssp() == 0) { ibt_violation() SKIP(); } to have the inline asm exercised, even when cet is disabled. Can you explain what _get_ssp does? It seems it is included via x86intrin.h, and defined (on x86_64) as extern __inline unsigned long long __attribute__((__gnu_inline__, __always_inline__, __artificial__)) _get_ssp (void) { return __builtin_ia32_rdsspq (); } Would it be easier to define it using inline asm, eliminating the configure check for -mshstk? Or is it a complicated thing involving a cpuid check first? > + signal(SIGSEGV, segfault_handler); > + ibt_violation(); > + FAIL(); > +} > +#else > +void > +test_main(void) > +{ > +} Should use SKIP() Regards, /Niels -- Niels Möller. PGP-encrypted email is preferred. Keyid 368C6677. Internet email is subject to wholesale government surveillance.

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Re: [PATCH] x86: Build with -z ibt -z shstk if possible
by nisse＠lysator.liu.se 22 Mar '20

22 Mar '20

"H.J. Lu" <hjl.tools(a)gmail.com> writes: > Where should such a CET violation happen? I added a CET violation test to glibc: > > void (*funcp) (void); > funcp = mmap (NULL, 0x1000, PROT_EXEC | PROT_READ | PROT_WRITE, > MAP_ANONYMOUS | MAP_PRIVATE, -1); > printf ("mmap = %p\n", funcp); > /* Write RET instruction. */ > *(char *) funcp = 0xc3; > funcp (); > > I can do something similar. But it is independent of nettle. The reason it makes sense to have such a test in nettle is that nettle includes code (your patch) that affects if cet works. If practical, I'd prefer to do it with inline assembly rather than constructing code at run time, to not have to worry about flushing caches. I suspect the tricky part is for the test to find out if cet protections are expected to work on the test system. Maybe one approch could be to have two test executables with a cet violation, one linking only to libc, and one linking also to nettle, hogweed and gmp. Then we'd expect that either both crash or none crash. > The regular tests have covered the nettle library with > > $ ./configure CC='gcc -fcf-protextion=full' && make && make check > > I got many CET violations on CET platform before my fix was merged. That's excellent. What I worry is, now that it's is working fine, if some later change accidentally breaks cet marks. If that's not detected by tests, then applications linking with nettle will not get the cet protection at runtime, despite being compiled with -fcf-protection=full. So it would be nice with an integration level test to catch that type of potential regression. It's a bit special to test security features; it's not enough to test that everything works fine in the absense of attack, we need tests to model the attacks, at least when that's practical. Regards, /Niels -- Niels Möller. PGP-encrypted email is preferred. Keyid 368C6677. Internet email is subject to wholesale government surveillance.

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