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| Current File : //usr/src/lib/libcrypt/crypt-sha256.c |
/*
* 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: release/9.1.0/lib/libcrypt/crypt-sha256.c 221471 2011-05-05 01:09:42Z obrien $");
#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
static char *
crypt_sha256_r(const char *key, const char *salt, char *buffer, int buflen)
{
u_long srounds;
int n;
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 = stpncpy(buffer, sha256_salt_prefix, MAX(0, buflen));
buflen -= sizeof(sha256_salt_prefix) - 1;
if (rounds_custom) {
n = snprintf(cp, MAX(0, buflen), "%s%zu$",
sha256_rounds_prefix, rounds);
cp += n;
buflen -= n;
}
cp = stpncpy(cp, salt, MIN((size_t)MAX(0, buflen), salt_len));
buflen -= MIN((size_t)MAX(0, buflen), salt_len);
if (buflen > 0) {
*cp++ = '$';
--buflen;
}
b64_from_24bit(alt_result[0], alt_result[10], alt_result[20], 4, &buflen, &cp);
b64_from_24bit(alt_result[21], alt_result[1], alt_result[11], 4, &buflen, &cp);
b64_from_24bit(alt_result[12], alt_result[22], alt_result[2], 4, &buflen, &cp);
b64_from_24bit(alt_result[3], alt_result[13], alt_result[23], 4, &buflen, &cp);
b64_from_24bit(alt_result[24], alt_result[4], alt_result[14], 4, &buflen, &cp);
b64_from_24bit(alt_result[15], alt_result[25], alt_result[5], 4, &buflen, &cp);
b64_from_24bit(alt_result[6], alt_result[16], alt_result[26], 4, &buflen, &cp);
b64_from_24bit(alt_result[27], alt_result[7], alt_result[17], 4, &buflen, &cp);
b64_from_24bit(alt_result[18], alt_result[28], alt_result[8], 4, &buflen, &cp);
b64_from_24bit(alt_result[9], alt_result[19], alt_result[29], 4, &buflen, &cp);
b64_from_24bit(0, alt_result[31], alt_result[30], 3, &buflen, &cp);
if (buflen <= 0) {
errno = ERANGE;
buffer = NULL;
}
else
*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 buffer;
}
/* This entry point is equivalent to crypt(3). */
char *
crypt_sha256(const char *key, const char *salt)
{
/* We don't want to have an arbitrary limit in the size of the
* password. We can compute an upper bound for the size of the
* result in advance and so we can prepare the buffer we pass to
* `crypt_sha256_r'. */
static char *buffer;
static int buflen;
int needed;
char *new_buffer;
needed = (sizeof(sha256_salt_prefix) - 1
+ sizeof(sha256_rounds_prefix) + 9 + 1
+ strlen(salt) + 1 + 43 + 1);
if (buflen < needed) {
new_buffer = (char *)realloc(buffer, needed);
if (new_buffer == NULL)
return NULL;
buffer = new_buffer;
buflen = needed;
}
return crypt_sha256_r(key, salt, buffer, buflen);
}
#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 */