forked from Imagelibrary/rtems
fe90ada455
context after they are finialized after r336539, so do not do it. Submitted by: David CARLIER <devnexen gmail com> MFC after: 1 month (after r336539) Differential Revision: https://reviews.freebsd.org/D16059
266 lines
8.2 KiB
C
266 lines
8.2 KiB
C
/*-
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* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
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*
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* Copyright (c) 2011 The FreeBSD Project. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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/* Based on:
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* SHA256-based Unix crypt implementation. Released into the Public Domain by
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* Ulrich Drepper <drepper@redhat.com>. */
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <sys/endian.h>
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#include <sys/param.h>
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#include <errno.h>
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#include <limits.h>
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#include <sha256.h>
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#include <stdbool.h>
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#include <stdint.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <crypt.h>
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/* Define our magic string to mark salt for SHA256 "encryption" replacement. */
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static const char sha256_salt_prefix[] = "$5$";
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/* Prefix for optional rounds specification. */
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static const char sha256_rounds_prefix[] = "rounds=";
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/* Maximum salt string length. */
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#define SALT_LEN_MAX 16
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/* Default number of rounds if not explicitly specified. */
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#define ROUNDS_DEFAULT 5000
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/* Minimum number of rounds. */
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#define ROUNDS_MIN 1000
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/* Maximum number of rounds. */
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#define ROUNDS_MAX 999999999
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char *
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crypt_sha256_r(const char *key, const char *salt, struct crypt_data *data)
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{
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u_long srounds;
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int n;
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uint8_t alt_result[32], temp_result[32];
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SHA256_CTX ctx, alt_ctx;
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size_t salt_len, key_len, cnt, rounds;
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char *cp, *p_bytes, *s_bytes, *endp;
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const char *num;
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bool rounds_custom;
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char *buffer = &data->buffer[0];
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int buflen = (int)sizeof(data->buffer);
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/* Default number of rounds. */
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rounds = ROUNDS_DEFAULT;
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rounds_custom = false;
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/* Find beginning of salt string. The prefix should normally always
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* be present. Just in case it is not. */
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if (strncmp(sha256_salt_prefix, salt, sizeof(sha256_salt_prefix) - 1) == 0)
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/* Skip salt prefix. */
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salt += sizeof(sha256_salt_prefix) - 1;
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if (strncmp(salt, sha256_rounds_prefix, sizeof(sha256_rounds_prefix) - 1)
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== 0) {
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num = salt + sizeof(sha256_rounds_prefix) - 1;
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srounds = strtoul(num, &endp, 10);
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if (*endp == '$') {
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salt = endp + 1;
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rounds = MAX(ROUNDS_MIN, MIN(srounds, ROUNDS_MAX));
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rounds_custom = true;
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}
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}
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salt_len = MIN(strcspn(salt, "$"), SALT_LEN_MAX);
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key_len = strlen(key);
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/* Prepare for the real work. */
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SHA256_Init(&ctx);
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/* Add the key string. */
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SHA256_Update(&ctx, key, key_len);
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/* The last part is the salt string. This must be at most 8
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* characters and it ends at the first `$' character (for
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* compatibility with existing implementations). */
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SHA256_Update(&ctx, salt, salt_len);
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/* Compute alternate SHA256 sum with input KEY, SALT, and KEY. The
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* final result will be added to the first context. */
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SHA256_Init(&alt_ctx);
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/* Add key. */
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SHA256_Update(&alt_ctx, key, key_len);
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/* Add salt. */
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SHA256_Update(&alt_ctx, salt, salt_len);
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/* Add key again. */
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SHA256_Update(&alt_ctx, key, key_len);
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/* Now get result of this (32 bytes) and add it to the other context. */
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SHA256_Final(alt_result, &alt_ctx);
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/* Add for any character in the key one byte of the alternate sum. */
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for (cnt = key_len; cnt > 32; cnt -= 32)
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SHA256_Update(&ctx, alt_result, 32);
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SHA256_Update(&ctx, alt_result, cnt);
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/* Take the binary representation of the length of the key and for
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* every 1 add the alternate sum, for every 0 the key. */
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for (cnt = key_len; cnt > 0; cnt >>= 1)
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if ((cnt & 1) != 0)
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SHA256_Update(&ctx, alt_result, 32);
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else
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SHA256_Update(&ctx, key, key_len);
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/* Create intermediate result. */
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SHA256_Final(alt_result, &ctx);
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/* Start computation of P byte sequence. */
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SHA256_Init(&alt_ctx);
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/* For every character in the password add the entire password. */
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for (cnt = 0; cnt < key_len; ++cnt)
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SHA256_Update(&alt_ctx, key, key_len);
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/* Finish the digest. */
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SHA256_Final(temp_result, &alt_ctx);
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/* Create byte sequence P. */
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cp = p_bytes = alloca(key_len);
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for (cnt = key_len; cnt >= 32; cnt -= 32) {
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memcpy(cp, temp_result, 32);
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cp += 32;
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}
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memcpy(cp, temp_result, cnt);
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/* Start computation of S byte sequence. */
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SHA256_Init(&alt_ctx);
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/* For every character in the password add the entire password. */
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for (cnt = 0; cnt < 16 + alt_result[0]; ++cnt)
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SHA256_Update(&alt_ctx, salt, salt_len);
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/* Finish the digest. */
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SHA256_Final(temp_result, &alt_ctx);
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/* Create byte sequence S. */
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cp = s_bytes = alloca(salt_len);
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for (cnt = salt_len; cnt >= 32; cnt -= 32) {
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memcpy(cp, temp_result, 32);
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cp += 32;
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}
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memcpy(cp, temp_result, cnt);
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/* Repeatedly run the collected hash value through SHA256 to burn CPU
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* cycles. */
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for (cnt = 0; cnt < rounds; ++cnt) {
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/* New context. */
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SHA256_Init(&ctx);
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/* Add key or last result. */
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if ((cnt & 1) != 0)
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SHA256_Update(&ctx, p_bytes, key_len);
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else
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SHA256_Update(&ctx, alt_result, 32);
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/* Add salt for numbers not divisible by 3. */
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if (cnt % 3 != 0)
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SHA256_Update(&ctx, s_bytes, salt_len);
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/* Add key for numbers not divisible by 7. */
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if (cnt % 7 != 0)
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SHA256_Update(&ctx, p_bytes, key_len);
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/* Add key or last result. */
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if ((cnt & 1) != 0)
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SHA256_Update(&ctx, alt_result, 32);
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else
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SHA256_Update(&ctx, p_bytes, key_len);
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/* Create intermediate result. */
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SHA256_Final(alt_result, &ctx);
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}
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/* Now we can construct the result string. It consists of three
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* parts. */
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cp = stpncpy(buffer, sha256_salt_prefix, MAX(0, buflen));
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buflen -= sizeof(sha256_salt_prefix) - 1;
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if (rounds_custom) {
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n = snprintf(cp, MAX(0, buflen), "%s%zu$",
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sha256_rounds_prefix, rounds);
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cp += n;
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buflen -= n;
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}
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cp = stpncpy(cp, salt, MIN((size_t)MAX(0, buflen), salt_len));
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buflen -= MIN((size_t)MAX(0, buflen), salt_len);
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if (buflen > 0) {
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*cp++ = '$';
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--buflen;
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}
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b64_from_24bit(alt_result[0], alt_result[10], alt_result[20], 4, &buflen, &cp);
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b64_from_24bit(alt_result[21], alt_result[1], alt_result[11], 4, &buflen, &cp);
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b64_from_24bit(alt_result[12], alt_result[22], alt_result[2], 4, &buflen, &cp);
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b64_from_24bit(alt_result[3], alt_result[13], alt_result[23], 4, &buflen, &cp);
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b64_from_24bit(alt_result[24], alt_result[4], alt_result[14], 4, &buflen, &cp);
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b64_from_24bit(alt_result[15], alt_result[25], alt_result[5], 4, &buflen, &cp);
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b64_from_24bit(alt_result[6], alt_result[16], alt_result[26], 4, &buflen, &cp);
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b64_from_24bit(alt_result[27], alt_result[7], alt_result[17], 4, &buflen, &cp);
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b64_from_24bit(alt_result[18], alt_result[28], alt_result[8], 4, &buflen, &cp);
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b64_from_24bit(alt_result[9], alt_result[19], alt_result[29], 4, &buflen, &cp);
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b64_from_24bit(0, alt_result[31], alt_result[30], 3, &buflen, &cp);
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if (buflen <= 0) {
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errno = ERANGE;
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buffer = NULL;
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}
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else
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*cp = '\0'; /* Terminate the string. */
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/* Clear the buffer for the intermediate result so that people
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* attaching to processes or reading core dumps cannot get any
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* information. We do it in this way to clear correct_words[] inside
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* the SHA256 implementation as well. */
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SHA256_Init(&ctx);
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SHA256_Final(alt_result, &ctx);
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memset(temp_result, '\0', sizeof(temp_result));
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memset(p_bytes, '\0', key_len);
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memset(s_bytes, '\0', salt_len);
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return buffer;
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}
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struct crypt_format crypt_sha256_format =
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CRYPT_FORMAT_INITIALIZER(crypt_sha256_r, "$5$");
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