diff options
Diffstat (limited to 'lib/libcrypt/crypt-sha256.c')
| -rw-r--r-- | lib/libcrypt/crypt-sha256.c | 477 |
1 files changed, 477 insertions, 0 deletions
diff --git a/lib/libcrypt/crypt-sha256.c b/lib/libcrypt/crypt-sha256.c new file mode 100644 index 0000000..d9e4ea6 --- /dev/null +++ b/lib/libcrypt/crypt-sha256.c @@ -0,0 +1,477 @@ +/* + * 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 + +static char * +sha256_crypt_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 * +sha256_crypt(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 + * `sha256_crypt_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 sha256_crypt_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 = sha256_crypt(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 */ |
