| /* One way encryption based on SHA512 sum. |
| Copyright (C) 2007-2018 Free Software Foundation, Inc. |
| This file is part of the GNU C Library. |
| Contributed by Ulrich Drepper <drepper@redhat.com>, 2007. |
| |
| The GNU C Library is free software; you can redistribute it and/or |
| modify it under the terms of the GNU Lesser General Public |
| License as published by the Free Software Foundation; either |
| version 2.1 of the License, or (at your option) any later version. |
| |
| The GNU C Library 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 |
| Lesser General Public License for more details. |
| |
| You should have received a copy of the GNU Lesser General Public |
| License along with the GNU C Library; if not, see |
| <http://www.gnu.org/licenses/>. */ |
| |
| #include <assert.h> |
| #include <errno.h> |
| #include <stdbool.h> |
| #include <stdlib.h> |
| #include <string.h> |
| #include <stdint.h> |
| #include <sys/param.h> |
| |
| #include "sha512.h" |
| #include "crypt-private.h" |
| |
| |
| #ifdef USE_NSS |
| typedef int PRBool; |
| # include <hasht.h> |
| # include <nsslowhash.h> |
| |
| # define sha512_init_ctx(ctxp, nss_ctxp) \ |
| do \ |
| { \ |
| if (((nss_ctxp = NSSLOWHASH_NewContext (nss_ictx, HASH_AlgSHA512)) \ |
| == NULL)) \ |
| { \ |
| if (nss_ctx != NULL) \ |
| NSSLOWHASH_Destroy (nss_ctx); \ |
| if (nss_alt_ctx != NULL) \ |
| NSSLOWHASH_Destroy (nss_alt_ctx); \ |
| return NULL; \ |
| } \ |
| NSSLOWHASH_Begin (nss_ctxp); \ |
| } \ |
| while (0) |
| |
| # define sha512_process_bytes(buf, len, ctxp, nss_ctxp) \ |
| NSSLOWHASH_Update (nss_ctxp, (const unsigned char *) buf, len) |
| |
| # define sha512_finish_ctx(ctxp, nss_ctxp, result) \ |
| do \ |
| { \ |
| unsigned int ret; \ |
| NSSLOWHASH_End (nss_ctxp, result, &ret, sizeof (result)); \ |
| assert (ret == sizeof (result)); \ |
| NSSLOWHASH_Destroy (nss_ctxp); \ |
| nss_ctxp = NULL; \ |
| } \ |
| while (0) |
| #else |
| # define sha512_init_ctx(ctxp, nss_ctxp) \ |
| __sha512_init_ctx (ctxp) |
| |
| # define sha512_process_bytes(buf, len, ctxp, nss_ctxp) \ |
| __sha512_process_bytes(buf, len, ctxp) |
| |
| # define sha512_finish_ctx(ctxp, nss_ctxp, result) \ |
| __sha512_finish_ctx (ctxp, result) |
| #endif |
| |
| |
| /* Define our magic string to mark salt for SHA512 "encryption" |
| replacement. */ |
| static const char sha512_salt_prefix[] = "$6$"; |
| |
| /* Prefix for optional rounds specification. */ |
| static const char sha512_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 |
| |
| |
| /* Prototypes for local functions. */ |
| extern char *__sha512_crypt_r (const char *key, const char *salt, |
| char *buffer, int buflen); |
| extern char *__sha512_crypt (const char *key, const char *salt); |
| |
| |
| char * |
| __sha512_crypt_r (const char *key, const char *salt, char *buffer, int buflen) |
| { |
| unsigned char alt_result[64] |
| __attribute__ ((__aligned__ (__alignof__ (uint64_t)))); |
| unsigned char temp_result[64] |
| __attribute__ ((__aligned__ (__alignof__ (uint64_t)))); |
| size_t salt_len; |
| size_t key_len; |
| size_t cnt; |
| char *cp; |
| char *copied_key = NULL; |
| char *copied_salt = NULL; |
| char *p_bytes; |
| char *s_bytes; |
| /* Default number of rounds. */ |
| size_t rounds = ROUNDS_DEFAULT; |
| bool rounds_custom = false; |
| size_t alloca_used = 0; |
| char *free_key = NULL; |
| char *free_pbytes = NULL; |
| |
| /* Find beginning of salt string. The prefix should normally always |
| be present. Just in case it is not. */ |
| if (strncmp (sha512_salt_prefix, salt, sizeof (sha512_salt_prefix) - 1) == 0) |
| /* Skip salt prefix. */ |
| salt += sizeof (sha512_salt_prefix) - 1; |
| |
| if (strncmp (salt, sha512_rounds_prefix, sizeof (sha512_rounds_prefix) - 1) |
| == 0) |
| { |
| const char *num = salt + sizeof (sha512_rounds_prefix) - 1; |
| char *endp; |
| unsigned long int 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); |
| |
| if ((key - (char *) 0) % __alignof__ (uint64_t) != 0) |
| { |
| char *tmp; |
| |
| if (__libc_use_alloca (alloca_used + key_len + __alignof__ (uint64_t))) |
| tmp = alloca_account (key_len + __alignof__ (uint64_t), alloca_used); |
| else |
| { |
| free_key = tmp = (char *) malloc (key_len + __alignof__ (uint64_t)); |
| if (tmp == NULL) |
| return NULL; |
| } |
| |
| key = copied_key = |
| memcpy (tmp + __alignof__ (uint64_t) |
| - (tmp - (char *) 0) % __alignof__ (uint64_t), |
| key, key_len); |
| assert ((key - (char *) 0) % __alignof__ (uint64_t) == 0); |
| } |
| |
| if ((salt - (char *) 0) % __alignof__ (uint64_t) != 0) |
| { |
| char *tmp = (char *) alloca (salt_len + __alignof__ (uint64_t)); |
| salt = copied_salt = |
| memcpy (tmp + __alignof__ (uint64_t) |
| - (tmp - (char *) 0) % __alignof__ (uint64_t), |
| salt, salt_len); |
| assert ((salt - (char *) 0) % __alignof__ (uint64_t) == 0); |
| } |
| |
| #ifdef USE_NSS |
| /* Initialize libfreebl3. */ |
| NSSLOWInitContext *nss_ictx = NSSLOW_Init (); |
| if (nss_ictx == NULL) |
| { |
| free (free_key); |
| return NULL; |
| } |
| NSSLOWHASHContext *nss_ctx = NULL; |
| NSSLOWHASHContext *nss_alt_ctx = NULL; |
| #else |
| struct sha512_ctx ctx; |
| struct sha512_ctx alt_ctx; |
| #endif |
| |
| /* Prepare for the real work. */ |
| sha512_init_ctx (&ctx, nss_ctx); |
| |
| /* Add the key string. */ |
| sha512_process_bytes (key, key_len, &ctx, nss_ctx); |
| |
| /* The last part is the salt string. This must be at most 16 |
| characters and it ends at the first `$' character. */ |
| sha512_process_bytes (salt, salt_len, &ctx, nss_ctx); |
| |
| |
| /* Compute alternate SHA512 sum with input KEY, SALT, and KEY. The |
| final result will be added to the first context. */ |
| sha512_init_ctx (&alt_ctx, nss_alt_ctx); |
| |
| /* Add key. */ |
| sha512_process_bytes (key, key_len, &alt_ctx, nss_alt_ctx); |
| |
| /* Add salt. */ |
| sha512_process_bytes (salt, salt_len, &alt_ctx, nss_alt_ctx); |
| |
| /* Add key again. */ |
| sha512_process_bytes (key, key_len, &alt_ctx, nss_alt_ctx); |
| |
| /* Now get result of this (64 bytes) and add it to the other |
| context. */ |
| sha512_finish_ctx (&alt_ctx, nss_alt_ctx, alt_result); |
| |
| /* Add for any character in the key one byte of the alternate sum. */ |
| for (cnt = key_len; cnt > 64; cnt -= 64) |
| sha512_process_bytes (alt_result, 64, &ctx, nss_ctx); |
| sha512_process_bytes (alt_result, cnt, &ctx, nss_ctx); |
| |
| /* 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) |
| sha512_process_bytes (alt_result, 64, &ctx, nss_ctx); |
| else |
| sha512_process_bytes (key, key_len, &ctx, nss_ctx); |
| |
| /* Create intermediate result. */ |
| sha512_finish_ctx (&ctx, nss_ctx, alt_result); |
| |
| /* Start computation of P byte sequence. */ |
| sha512_init_ctx (&alt_ctx, nss_alt_ctx); |
| |
| /* For every character in the password add the entire password. */ |
| for (cnt = 0; cnt < key_len; ++cnt) |
| sha512_process_bytes (key, key_len, &alt_ctx, nss_alt_ctx); |
| |
| /* Finish the digest. */ |
| sha512_finish_ctx (&alt_ctx, nss_alt_ctx, temp_result); |
| |
| /* Create byte sequence P. */ |
| if (__libc_use_alloca (alloca_used + key_len)) |
| cp = p_bytes = (char *) alloca (key_len); |
| else |
| { |
| free_pbytes = cp = p_bytes = (char *)malloc (key_len); |
| if (free_pbytes == NULL) |
| { |
| free (free_key); |
| return NULL; |
| } |
| } |
| |
| for (cnt = key_len; cnt >= 64; cnt -= 64) |
| cp = mempcpy (cp, temp_result, 64); |
| memcpy (cp, temp_result, cnt); |
| |
| /* Start computation of S byte sequence. */ |
| sha512_init_ctx (&alt_ctx, nss_alt_ctx); |
| |
| /* For every character in the password add the entire password. */ |
| for (cnt = 0; cnt < 16 + alt_result[0]; ++cnt) |
| sha512_process_bytes (salt, salt_len, &alt_ctx, nss_alt_ctx); |
| |
| /* Finish the digest. */ |
| sha512_finish_ctx (&alt_ctx, nss_alt_ctx, temp_result); |
| |
| /* Create byte sequence S. */ |
| cp = s_bytes = alloca (salt_len); |
| for (cnt = salt_len; cnt >= 64; cnt -= 64) |
| cp = mempcpy (cp, temp_result, 64); |
| memcpy (cp, temp_result, cnt); |
| |
| /* Repeatedly run the collected hash value through SHA512 to burn |
| CPU cycles. */ |
| for (cnt = 0; cnt < rounds; ++cnt) |
| { |
| /* New context. */ |
| sha512_init_ctx (&ctx, nss_ctx); |
| |
| /* Add key or last result. */ |
| if ((cnt & 1) != 0) |
| sha512_process_bytes (p_bytes, key_len, &ctx, nss_ctx); |
| else |
| sha512_process_bytes (alt_result, 64, &ctx, nss_ctx); |
| |
| /* Add salt for numbers not divisible by 3. */ |
| if (cnt % 3 != 0) |
| sha512_process_bytes (s_bytes, salt_len, &ctx, nss_ctx); |
| |
| /* Add key for numbers not divisible by 7. */ |
| if (cnt % 7 != 0) |
| sha512_process_bytes (p_bytes, key_len, &ctx, nss_ctx); |
| |
| /* Add key or last result. */ |
| if ((cnt & 1) != 0) |
| sha512_process_bytes (alt_result, 64, &ctx, nss_ctx); |
| else |
| sha512_process_bytes (p_bytes, key_len, &ctx, nss_ctx); |
| |
| /* Create intermediate result. */ |
| sha512_finish_ctx (&ctx, nss_ctx, alt_result); |
| } |
| |
| #ifdef USE_NSS |
| /* Free libfreebl3 resources. */ |
| NSSLOW_Shutdown (nss_ictx); |
| #endif |
| |
| /* Now we can construct the result string. It consists of three |
| parts. */ |
| cp = __stpncpy (buffer, sha512_salt_prefix, MAX (0, buflen)); |
| buflen -= sizeof (sha512_salt_prefix) - 1; |
| |
| if (rounds_custom) |
| { |
| int n = __snprintf (cp, MAX (0, buflen), "%s%zu$", |
| sha512_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 (&cp, &buflen, |
| alt_result[0], alt_result[21], alt_result[42], 4); |
| __b64_from_24bit (&cp, &buflen, |
| alt_result[22], alt_result[43], alt_result[1], 4); |
| __b64_from_24bit (&cp, &buflen, |
| alt_result[44], alt_result[2], alt_result[23], 4); |
| __b64_from_24bit (&cp, &buflen, |
| alt_result[3], alt_result[24], alt_result[45], 4); |
| __b64_from_24bit (&cp, &buflen, |
| alt_result[25], alt_result[46], alt_result[4], 4); |
| __b64_from_24bit (&cp, &buflen, |
| alt_result[47], alt_result[5], alt_result[26], 4); |
| __b64_from_24bit (&cp, &buflen, |
| alt_result[6], alt_result[27], alt_result[48], 4); |
| __b64_from_24bit (&cp, &buflen, |
| alt_result[28], alt_result[49], alt_result[7], 4); |
| __b64_from_24bit (&cp, &buflen, |
| alt_result[50], alt_result[8], alt_result[29], 4); |
| __b64_from_24bit (&cp, &buflen, |
| alt_result[9], alt_result[30], alt_result[51], 4); |
| __b64_from_24bit (&cp, &buflen, |
| alt_result[31], alt_result[52], alt_result[10], 4); |
| __b64_from_24bit (&cp, &buflen, |
| alt_result[53], alt_result[11], alt_result[32], 4); |
| __b64_from_24bit (&cp, &buflen, |
| alt_result[12], alt_result[33], alt_result[54], 4); |
| __b64_from_24bit (&cp, &buflen, |
| alt_result[34], alt_result[55], alt_result[13], 4); |
| __b64_from_24bit (&cp, &buflen, |
| alt_result[56], alt_result[14], alt_result[35], 4); |
| __b64_from_24bit (&cp, &buflen, |
| alt_result[15], alt_result[36], alt_result[57], 4); |
| __b64_from_24bit (&cp, &buflen, |
| alt_result[37], alt_result[58], alt_result[16], 4); |
| __b64_from_24bit (&cp, &buflen, |
| alt_result[59], alt_result[17], alt_result[38], 4); |
| __b64_from_24bit (&cp, &buflen, |
| alt_result[18], alt_result[39], alt_result[60], 4); |
| __b64_from_24bit (&cp, &buflen, |
| alt_result[40], alt_result[61], alt_result[19], 4); |
| __b64_from_24bit (&cp, &buflen, |
| alt_result[62], alt_result[20], alt_result[41], 4); |
| __b64_from_24bit (&cp, &buflen, |
| 0, 0, alt_result[63], 2); |
| |
| if (buflen <= 0) |
| { |
| __set_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 SHA512 implementation as well. */ |
| #ifndef USE_NSS |
| __sha512_init_ctx (&ctx); |
| __sha512_finish_ctx (&ctx, alt_result); |
| explicit_bzero (&ctx, sizeof (ctx)); |
| explicit_bzero (&alt_ctx, sizeof (alt_ctx)); |
| #endif |
| explicit_bzero (temp_result, sizeof (temp_result)); |
| explicit_bzero (p_bytes, key_len); |
| explicit_bzero (s_bytes, salt_len); |
| if (copied_key != NULL) |
| explicit_bzero (copied_key, key_len); |
| if (copied_salt != NULL) |
| explicit_bzero (copied_salt, salt_len); |
| |
| free (free_key); |
| free (free_pbytes); |
| return buffer; |
| } |
| |
| #ifndef _LIBC |
| # define libc_freeres_ptr(decl) decl |
| #endif |
| libc_freeres_ptr (static char *buffer); |
| |
| /* This entry point is equivalent to the `crypt' function in Unix |
| libcs. */ |
| char * |
| __sha512_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 |
| `sha512_crypt_r'. */ |
| static int buflen; |
| int needed = (sizeof (sha512_salt_prefix) - 1 |
| + sizeof (sha512_rounds_prefix) + 9 + 1 |
| + strlen (salt) + 1 + 86 + 1); |
| |
| if (buflen < needed) |
| { |
| char *new_buffer = (char *) realloc (buffer, needed); |
| if (new_buffer == NULL) |
| return NULL; |
| |
| buffer = new_buffer; |
| buflen = needed; |
| } |
| |
| return __sha512_crypt_r (key, salt, buffer, buflen); |
| } |
| |
| #ifndef _LIBC |
| static void |
| __attribute__ ((__destructor__)) |
| free_mem (void) |
| { |
| free (buffer); |
| } |
| #endif |