freebsd-skq/lib/libcrypt/crypt-sha256.c
Pedro F. Giffuni 5e53a4f90f lib: further adoption of SPDX licensing ID tags.
Mainly focus on files that use BSD 2-Clause license, however the tool I
was using mis-identified many licenses so this was mostly a manual - error
prone - task.

The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.
2017-11-26 02:00:33 +00:00

434 lines
13 KiB
C

/*-
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
*
* Copyright (c) 2011 The FreeBSD Project. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
/* Based on:
* SHA256-based Unix crypt implementation. Released into the Public Domain by
* Ulrich Drepper <drepper@redhat.com>. */
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/endian.h>
#include <sys/param.h>
#include <errno.h>
#include <limits.h>
#include <sha256.h>
#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "crypt.h"
/* Define our magic string to mark salt for SHA256 "encryption" replacement. */
static const char sha256_salt_prefix[] = "$5$";
/* Prefix for optional rounds specification. */
static const char sha256_rounds_prefix[] = "rounds=";
/* Maximum salt string length. */
#define SALT_LEN_MAX 16
/* Default number of rounds if not explicitly specified. */
#define ROUNDS_DEFAULT 5000
/* Minimum number of rounds. */
#define ROUNDS_MIN 1000
/* Maximum number of rounds. */
#define ROUNDS_MAX 999999999
int
crypt_sha256(const char *key, const char *salt, char *buffer)
{
u_long srounds;
uint8_t alt_result[32], temp_result[32];
SHA256_CTX ctx, alt_ctx;
size_t salt_len, key_len, cnt, rounds;
char *cp, *copied_key, *copied_salt, *p_bytes, *s_bytes, *endp;
const char *num;
bool rounds_custom;
copied_key = NULL;
copied_salt = NULL;
/* Default number of rounds. */
rounds = ROUNDS_DEFAULT;
rounds_custom = false;
/* Find beginning of salt string. The prefix should normally always
* be present. Just in case it is not. */
if (strncmp(sha256_salt_prefix, salt, sizeof(sha256_salt_prefix) - 1) == 0)
/* Skip salt prefix. */
salt += sizeof(sha256_salt_prefix) - 1;
if (strncmp(salt, sha256_rounds_prefix, sizeof(sha256_rounds_prefix) - 1)
== 0) {
num = salt + sizeof(sha256_rounds_prefix) - 1;
srounds = strtoul(num, &endp, 10);
if (*endp == '$') {
salt = endp + 1;
rounds = MAX(ROUNDS_MIN, MIN(srounds, ROUNDS_MAX));
rounds_custom = true;
}
}
salt_len = MIN(strcspn(salt, "$"), SALT_LEN_MAX);
key_len = strlen(key);
/* Prepare for the real work. */
SHA256_Init(&ctx);
/* Add the key string. */
SHA256_Update(&ctx, key, key_len);
/* The last part is the salt string. This must be at most 8
* characters and it ends at the first `$' character (for
* compatibility with existing implementations). */
SHA256_Update(&ctx, salt, salt_len);
/* Compute alternate SHA256 sum with input KEY, SALT, and KEY. The
* final result will be added to the first context. */
SHA256_Init(&alt_ctx);
/* Add key. */
SHA256_Update(&alt_ctx, key, key_len);
/* Add salt. */
SHA256_Update(&alt_ctx, salt, salt_len);
/* Add key again. */
SHA256_Update(&alt_ctx, key, key_len);
/* Now get result of this (32 bytes) and add it to the other context. */
SHA256_Final(alt_result, &alt_ctx);
/* Add for any character in the key one byte of the alternate sum. */
for (cnt = key_len; cnt > 32; cnt -= 32)
SHA256_Update(&ctx, alt_result, 32);
SHA256_Update(&ctx, alt_result, cnt);
/* Take the binary representation of the length of the key and for
* every 1 add the alternate sum, for every 0 the key. */
for (cnt = key_len; cnt > 0; cnt >>= 1)
if ((cnt & 1) != 0)
SHA256_Update(&ctx, alt_result, 32);
else
SHA256_Update(&ctx, key, key_len);
/* Create intermediate result. */
SHA256_Final(alt_result, &ctx);
/* Start computation of P byte sequence. */
SHA256_Init(&alt_ctx);
/* For every character in the password add the entire password. */
for (cnt = 0; cnt < key_len; ++cnt)
SHA256_Update(&alt_ctx, key, key_len);
/* Finish the digest. */
SHA256_Final(temp_result, &alt_ctx);
/* Create byte sequence P. */
cp = p_bytes = alloca(key_len);
for (cnt = key_len; cnt >= 32; cnt -= 32) {
memcpy(cp, temp_result, 32);
cp += 32;
}
memcpy(cp, temp_result, cnt);
/* Start computation of S byte sequence. */
SHA256_Init(&alt_ctx);
/* For every character in the password add the entire password. */
for (cnt = 0; cnt < 16 + alt_result[0]; ++cnt)
SHA256_Update(&alt_ctx, salt, salt_len);
/* Finish the digest. */
SHA256_Final(temp_result, &alt_ctx);
/* Create byte sequence S. */
cp = s_bytes = alloca(salt_len);
for (cnt = salt_len; cnt >= 32; cnt -= 32) {
memcpy(cp, temp_result, 32);
cp += 32;
}
memcpy(cp, temp_result, cnt);
/* Repeatedly run the collected hash value through SHA256 to burn CPU
* cycles. */
for (cnt = 0; cnt < rounds; ++cnt) {
/* New context. */
SHA256_Init(&ctx);
/* Add key or last result. */
if ((cnt & 1) != 0)
SHA256_Update(&ctx, p_bytes, key_len);
else
SHA256_Update(&ctx, alt_result, 32);
/* Add salt for numbers not divisible by 3. */
if (cnt % 3 != 0)
SHA256_Update(&ctx, s_bytes, salt_len);
/* Add key for numbers not divisible by 7. */
if (cnt % 7 != 0)
SHA256_Update(&ctx, p_bytes, key_len);
/* Add key or last result. */
if ((cnt & 1) != 0)
SHA256_Update(&ctx, alt_result, 32);
else
SHA256_Update(&ctx, p_bytes, key_len);
/* Create intermediate result. */
SHA256_Final(alt_result, &ctx);
}
/* Now we can construct the result string. It consists of three
* parts. */
cp = stpcpy(buffer, sha256_salt_prefix);
if (rounds_custom)
cp += sprintf(cp, "%s%zu$", sha256_rounds_prefix, rounds);
cp = stpncpy(cp, salt, salt_len);
*cp++ = '$';
b64_from_24bit(alt_result[0], alt_result[10], alt_result[20], 4, &cp);
b64_from_24bit(alt_result[21], alt_result[1], alt_result[11], 4, &cp);
b64_from_24bit(alt_result[12], alt_result[22], alt_result[2], 4, &cp);
b64_from_24bit(alt_result[3], alt_result[13], alt_result[23], 4, &cp);
b64_from_24bit(alt_result[24], alt_result[4], alt_result[14], 4, &cp);
b64_from_24bit(alt_result[15], alt_result[25], alt_result[5], 4, &cp);
b64_from_24bit(alt_result[6], alt_result[16], alt_result[26], 4, &cp);
b64_from_24bit(alt_result[27], alt_result[7], alt_result[17], 4, &cp);
b64_from_24bit(alt_result[18], alt_result[28], alt_result[8], 4, &cp);
b64_from_24bit(alt_result[9], alt_result[19], alt_result[29], 4, &cp);
b64_from_24bit(0, alt_result[31], alt_result[30], 3, &cp);
*cp = '\0'; /* Terminate the string. */
/* Clear the buffer for the intermediate result so that people
* attaching to processes or reading core dumps cannot get any
* information. We do it in this way to clear correct_words[] inside
* the SHA256 implementation as well. */
SHA256_Init(&ctx);
SHA256_Final(alt_result, &ctx);
memset(temp_result, '\0', sizeof(temp_result));
memset(p_bytes, '\0', key_len);
memset(s_bytes, '\0', salt_len);
memset(&ctx, '\0', sizeof(ctx));
memset(&alt_ctx, '\0', sizeof(alt_ctx));
if (copied_key != NULL)
memset(copied_key, '\0', key_len);
if (copied_salt != NULL)
memset(copied_salt, '\0', salt_len);
return (0);
}
#ifdef TEST
static const struct {
const char *input;
const char result[32];
} tests[] =
{
/* Test vectors from FIPS 180-2: appendix B.1. */
{
"abc",
"\xba\x78\x16\xbf\x8f\x01\xcf\xea\x41\x41\x40\xde\x5d\xae\x22\x23"
"\xb0\x03\x61\xa3\x96\x17\x7a\x9c\xb4\x10\xff\x61\xf2\x00\x15\xad"
},
/* Test vectors from FIPS 180-2: appendix B.2. */
{
"abcdbcdecdefdefgefghfghighijhijkijkljklmklmnlmnomnopnopq",
"\x24\x8d\x6a\x61\xd2\x06\x38\xb8\xe5\xc0\x26\x93\x0c\x3e\x60\x39"
"\xa3\x3c\xe4\x59\x64\xff\x21\x67\xf6\xec\xed\xd4\x19\xdb\x06\xc1"
},
/* Test vectors from the NESSIE project. */
{
"",
"\xe3\xb0\xc4\x42\x98\xfc\x1c\x14\x9a\xfb\xf4\xc8\x99\x6f\xb9\x24"
"\x27\xae\x41\xe4\x64\x9b\x93\x4c\xa4\x95\x99\x1b\x78\x52\xb8\x55"
},
{
"a",
"\xca\x97\x81\x12\xca\x1b\xbd\xca\xfa\xc2\x31\xb3\x9a\x23\xdc\x4d"
"\xa7\x86\xef\xf8\x14\x7c\x4e\x72\xb9\x80\x77\x85\xaf\xee\x48\xbb"
},
{
"message digest",
"\xf7\x84\x6f\x55\xcf\x23\xe1\x4e\xeb\xea\xb5\xb4\xe1\x55\x0c\xad"
"\x5b\x50\x9e\x33\x48\xfb\xc4\xef\xa3\xa1\x41\x3d\x39\x3c\xb6\x50"
},
{
"abcdefghijklmnopqrstuvwxyz",
"\x71\xc4\x80\xdf\x93\xd6\xae\x2f\x1e\xfa\xd1\x44\x7c\x66\xc9\x52"
"\x5e\x31\x62\x18\xcf\x51\xfc\x8d\x9e\xd8\x32\xf2\xda\xf1\x8b\x73"
},
{
"abcdbcdecdefdefgefghfghighijhijkijkljklmklmnlmnomnopnopq",
"\x24\x8d\x6a\x61\xd2\x06\x38\xb8\xe5\xc0\x26\x93\x0c\x3e\x60\x39"
"\xa3\x3c\xe4\x59\x64\xff\x21\x67\xf6\xec\xed\xd4\x19\xdb\x06\xc1"
},
{
"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789",
"\xdb\x4b\xfc\xbd\x4d\xa0\xcd\x85\xa6\x0c\x3c\x37\xd3\xfb\xd8\x80"
"\x5c\x77\xf1\x5f\xc6\xb1\xfd\xfe\x61\x4e\xe0\xa7\xc8\xfd\xb4\xc0"
},
{
"123456789012345678901234567890123456789012345678901234567890"
"12345678901234567890",
"\xf3\x71\xbc\x4a\x31\x1f\x2b\x00\x9e\xef\x95\x2d\xd8\x3c\xa8\x0e"
"\x2b\x60\x02\x6c\x8e\x93\x55\x92\xd0\xf9\xc3\x08\x45\x3c\x81\x3e"
}
};
#define ntests (sizeof (tests) / sizeof (tests[0]))
static const struct {
const char *salt;
const char *input;
const char *expected;
} tests2[] =
{
{
"$5$saltstring", "Hello world!",
"$5$saltstring$5B8vYYiY.CVt1RlTTf8KbXBH3hsxY/GNooZaBBGWEc5"
},
{
"$5$rounds=10000$saltstringsaltstring", "Hello world!",
"$5$rounds=10000$saltstringsaltst$3xv.VbSHBb41AL9AvLeujZkZRBAwqFMz2."
"opqey6IcA"
},
{
"$5$rounds=5000$toolongsaltstring", "This is just a test",
"$5$rounds=5000$toolongsaltstrin$Un/5jzAHMgOGZ5.mWJpuVolil07guHPvOW8"
"mGRcvxa5"
},
{
"$5$rounds=1400$anotherlongsaltstring",
"a very much longer text to encrypt. This one even stretches over more"
"than one line.",
"$5$rounds=1400$anotherlongsalts$Rx.j8H.h8HjEDGomFU8bDkXm3XIUnzyxf12"
"oP84Bnq1"
},
{
"$5$rounds=77777$short",
"we have a short salt string but not a short password",
"$5$rounds=77777$short$JiO1O3ZpDAxGJeaDIuqCoEFysAe1mZNJRs3pw0KQRd/"
},
{
"$5$rounds=123456$asaltof16chars..", "a short string",
"$5$rounds=123456$asaltof16chars..$gP3VQ/6X7UUEW3HkBn2w1/Ptq2jxPyzV/"
"cZKmF/wJvD"
},
{
"$5$rounds=10$roundstoolow", "the minimum number is still observed",
"$5$rounds=1000$roundstoolow$yfvwcWrQ8l/K0DAWyuPMDNHpIVlTQebY9l/gL97"
"2bIC"
},
};
#define ntests2 (sizeof (tests2) / sizeof (tests2[0]))
int
main(void)
{
SHA256_CTX ctx;
uint8_t sum[32];
int result = 0;
int i, cnt;
for (cnt = 0; cnt < (int)ntests; ++cnt) {
SHA256_Init(&ctx);
SHA256_Update(&ctx, tests[cnt].input, strlen(tests[cnt].input));
SHA256_Final(sum, &ctx);
if (memcmp(tests[cnt].result, sum, 32) != 0) {
for (i = 0; i < 32; i++)
printf("%02X", tests[cnt].result[i]);
printf("\n");
for (i = 0; i < 32; i++)
printf("%02X", sum[i]);
printf("\n");
printf("test %d run %d failed\n", cnt, 1);
result = 1;
}
SHA256_Init(&ctx);
for (i = 0; tests[cnt].input[i] != '\0'; ++i)
SHA256_Update(&ctx, &tests[cnt].input[i], 1);
SHA256_Final(sum, &ctx);
if (memcmp(tests[cnt].result, sum, 32) != 0) {
for (i = 0; i < 32; i++)
printf("%02X", tests[cnt].result[i]);
printf("\n");
for (i = 0; i < 32; i++)
printf("%02X", sum[i]);
printf("\n");
printf("test %d run %d failed\n", cnt, 2);
result = 1;
}
}
/* Test vector from FIPS 180-2: appendix B.3. */
char buf[1000];
memset(buf, 'a', sizeof(buf));
SHA256_Init(&ctx);
for (i = 0; i < 1000; ++i)
SHA256_Update(&ctx, buf, sizeof(buf));
SHA256_Final(sum, &ctx);
static const char expected[32] =
"\xcd\xc7\x6e\x5c\x99\x14\xfb\x92\x81\xa1\xc7\xe2\x84\xd7\x3e\x67"
"\xf1\x80\x9a\x48\xa4\x97\x20\x0e\x04\x6d\x39\xcc\xc7\x11\x2c\xd0";
if (memcmp(expected, sum, 32) != 0) {
printf("test %d failed\n", cnt);
result = 1;
}
for (cnt = 0; cnt < ntests2; ++cnt) {
char *cp = crypt_sha256(tests2[cnt].input, tests2[cnt].salt);
if (strcmp(cp, tests2[cnt].expected) != 0) {
printf("test %d: expected \"%s\", got \"%s\"\n",
cnt, tests2[cnt].expected, cp);
result = 1;
}
}
if (result == 0)
puts("all tests OK");
return result;
}
#endif /* TEST */