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c3266dc0 | 1 | /* One way encryption based on SHA512 sum. |
bfff8b1b | 2 | Copyright (C) 2007-2017 Free Software Foundation, Inc. |
c3266dc0 UD |
3 | This file is part of the GNU C Library. |
4 | Contributed by Ulrich Drepper <drepper@redhat.com>, 2007. | |
5 | ||
6 | The GNU C Library is free software; you can redistribute it and/or | |
7 | modify it under the terms of the GNU Lesser General Public | |
8 | License as published by the Free Software Foundation; either | |
9 | version 2.1 of the License, or (at your option) any later version. | |
10 | ||
11 | The GNU C Library is distributed in the hope that it will be useful, | |
12 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
14 | Lesser General Public License for more details. | |
15 | ||
16 | You should have received a copy of the GNU Lesser General Public | |
59ba27a6 PE |
17 | License along with the GNU C Library; if not, see |
18 | <http://www.gnu.org/licenses/>. */ | |
c3266dc0 UD |
19 | |
20 | #include <assert.h> | |
21 | #include <errno.h> | |
22 | #include <stdbool.h> | |
23 | #include <stdlib.h> | |
24 | #include <string.h> | |
e054f494 | 25 | #include <stdint.h> |
c3266dc0 UD |
26 | #include <sys/param.h> |
27 | ||
28 | #include "sha512.h" | |
8747cd03 | 29 | #include "crypt-private.h" |
c3266dc0 UD |
30 | |
31 | ||
ff886b82 UD |
32 | #ifdef USE_NSS |
33 | typedef int PRBool; | |
34 | # include <hasht.h> | |
35 | # include <nsslowhash.h> | |
36 | ||
37 | # define sha512_init_ctx(ctxp, nss_ctxp) \ | |
38 | do \ | |
39 | { \ | |
40 | if (((nss_ctxp = NSSLOWHASH_NewContext (nss_ictx, HASH_AlgSHA512)) \ | |
41 | == NULL)) \ | |
42 | { \ | |
43 | if (nss_ctx != NULL) \ | |
44 | NSSLOWHASH_Destroy (nss_ctx); \ | |
45 | if (nss_alt_ctx != NULL) \ | |
46 | NSSLOWHASH_Destroy (nss_alt_ctx); \ | |
47 | return NULL; \ | |
48 | } \ | |
49 | NSSLOWHASH_Begin (nss_ctxp); \ | |
50 | } \ | |
51 | while (0) | |
52 | ||
53 | # define sha512_process_bytes(buf, len, ctxp, nss_ctxp) \ | |
54 | NSSLOWHASH_Update (nss_ctxp, (const unsigned char *) buf, len) | |
55 | ||
56 | # define sha512_finish_ctx(ctxp, nss_ctxp, result) \ | |
57 | do \ | |
58 | { \ | |
59 | unsigned int ret; \ | |
60 | NSSLOWHASH_End (nss_ctxp, result, &ret, sizeof (result)); \ | |
61 | assert (ret == sizeof (result)); \ | |
62 | NSSLOWHASH_Destroy (nss_ctxp); \ | |
63 | nss_ctxp = NULL; \ | |
64 | } \ | |
65 | while (0) | |
66 | #else | |
67 | # define sha512_init_ctx(ctxp, nss_ctxp) \ | |
68 | __sha512_init_ctx (ctxp) | |
69 | ||
70 | # define sha512_process_bytes(buf, len, ctxp, nss_ctxp) \ | |
71 | __sha512_process_bytes(buf, len, ctxp) | |
72 | ||
73 | # define sha512_finish_ctx(ctxp, nss_ctxp, result) \ | |
74 | __sha512_finish_ctx (ctxp, result) | |
75 | #endif | |
76 | ||
77 | ||
c3266dc0 UD |
78 | /* Define our magic string to mark salt for SHA512 "encryption" |
79 | replacement. */ | |
80 | static const char sha512_salt_prefix[] = "$6$"; | |
81 | ||
82 | /* Prefix for optional rounds specification. */ | |
83 | static const char sha512_rounds_prefix[] = "rounds="; | |
84 | ||
85 | /* Maximum salt string length. */ | |
86 | #define SALT_LEN_MAX 16 | |
87 | /* Default number of rounds if not explicitly specified. */ | |
88 | #define ROUNDS_DEFAULT 5000 | |
89 | /* Minimum number of rounds. */ | |
90 | #define ROUNDS_MIN 1000 | |
91 | /* Maximum number of rounds. */ | |
92 | #define ROUNDS_MAX 999999999 | |
93 | ||
c3266dc0 UD |
94 | |
95 | /* Prototypes for local functions. */ | |
96 | extern char *__sha512_crypt_r (const char *key, const char *salt, | |
97 | char *buffer, int buflen); | |
98 | extern char *__sha512_crypt (const char *key, const char *salt); | |
99 | ||
100 | ||
101 | char * | |
9dd346ff | 102 | __sha512_crypt_r (const char *key, const char *salt, char *buffer, int buflen) |
c3266dc0 UD |
103 | { |
104 | unsigned char alt_result[64] | |
105 | __attribute__ ((__aligned__ (__alignof__ (uint64_t)))); | |
106 | unsigned char temp_result[64] | |
107 | __attribute__ ((__aligned__ (__alignof__ (uint64_t)))); | |
c3266dc0 UD |
108 | size_t salt_len; |
109 | size_t key_len; | |
110 | size_t cnt; | |
111 | char *cp; | |
112 | char *copied_key = NULL; | |
113 | char *copied_salt = NULL; | |
114 | char *p_bytes; | |
115 | char *s_bytes; | |
116 | /* Default number of rounds. */ | |
117 | size_t rounds = ROUNDS_DEFAULT; | |
118 | bool rounds_custom = false; | |
b8dc394d JL |
119 | size_t alloca_used = 0; |
120 | char *free_key = NULL; | |
121 | char *free_pbytes = NULL; | |
c3266dc0 UD |
122 | |
123 | /* Find beginning of salt string. The prefix should normally always | |
124 | be present. Just in case it is not. */ | |
125 | if (strncmp (sha512_salt_prefix, salt, sizeof (sha512_salt_prefix) - 1) == 0) | |
126 | /* Skip salt prefix. */ | |
127 | salt += sizeof (sha512_salt_prefix) - 1; | |
128 | ||
129 | if (strncmp (salt, sha512_rounds_prefix, sizeof (sha512_rounds_prefix) - 1) | |
130 | == 0) | |
131 | { | |
132 | const char *num = salt + sizeof (sha512_rounds_prefix) - 1; | |
133 | char *endp; | |
134 | unsigned long int srounds = strtoul (num, &endp, 10); | |
135 | if (*endp == '$') | |
136 | { | |
137 | salt = endp + 1; | |
138 | rounds = MAX (ROUNDS_MIN, MIN (srounds, ROUNDS_MAX)); | |
139 | rounds_custom = true; | |
140 | } | |
141 | } | |
142 | ||
143 | salt_len = MIN (strcspn (salt, "$"), SALT_LEN_MAX); | |
144 | key_len = strlen (key); | |
145 | ||
146 | if ((key - (char *) 0) % __alignof__ (uint64_t) != 0) | |
147 | { | |
b8dc394d JL |
148 | char *tmp; |
149 | ||
150 | if (__libc_use_alloca (alloca_used + key_len + __alignof__ (uint64_t))) | |
151 | tmp = alloca_account (key_len + __alignof__ (uint64_t), alloca_used); | |
152 | else | |
153 | { | |
154 | free_key = tmp = (char *) malloc (key_len + __alignof__ (uint64_t)); | |
155 | if (tmp == NULL) | |
156 | return NULL; | |
157 | } | |
158 | ||
c3266dc0 UD |
159 | key = copied_key = |
160 | memcpy (tmp + __alignof__ (uint64_t) | |
161 | - (tmp - (char *) 0) % __alignof__ (uint64_t), | |
162 | key, key_len); | |
163 | assert ((key - (char *) 0) % __alignof__ (uint64_t) == 0); | |
164 | } | |
165 | ||
166 | if ((salt - (char *) 0) % __alignof__ (uint64_t) != 0) | |
167 | { | |
168 | char *tmp = (char *) alloca (salt_len + __alignof__ (uint64_t)); | |
169 | salt = copied_salt = | |
170 | memcpy (tmp + __alignof__ (uint64_t) | |
171 | - (tmp - (char *) 0) % __alignof__ (uint64_t), | |
172 | salt, salt_len); | |
173 | assert ((salt - (char *) 0) % __alignof__ (uint64_t) == 0); | |
174 | } | |
175 | ||
ff886b82 UD |
176 | #ifdef USE_NSS |
177 | /* Initialize libfreebl3. */ | |
178 | NSSLOWInitContext *nss_ictx = NSSLOW_Init (); | |
179 | if (nss_ictx == NULL) | |
b8dc394d JL |
180 | { |
181 | free (free_key); | |
182 | return NULL; | |
183 | } | |
ff886b82 UD |
184 | NSSLOWHASHContext *nss_ctx = NULL; |
185 | NSSLOWHASHContext *nss_alt_ctx = NULL; | |
186 | #else | |
187 | struct sha512_ctx ctx; | |
188 | struct sha512_ctx alt_ctx; | |
189 | #endif | |
190 | ||
c3266dc0 | 191 | /* Prepare for the real work. */ |
ff886b82 | 192 | sha512_init_ctx (&ctx, nss_ctx); |
c3266dc0 UD |
193 | |
194 | /* Add the key string. */ | |
ff886b82 | 195 | sha512_process_bytes (key, key_len, &ctx, nss_ctx); |
c3266dc0 | 196 | |
7f745396 UD |
197 | /* The last part is the salt string. This must be at most 16 |
198 | characters and it ends at the first `$' character. */ | |
ff886b82 | 199 | sha512_process_bytes (salt, salt_len, &ctx, nss_ctx); |
c3266dc0 UD |
200 | |
201 | ||
202 | /* Compute alternate SHA512 sum with input KEY, SALT, and KEY. The | |
203 | final result will be added to the first context. */ | |
ff886b82 | 204 | sha512_init_ctx (&alt_ctx, nss_alt_ctx); |
c3266dc0 UD |
205 | |
206 | /* Add key. */ | |
ff886b82 | 207 | sha512_process_bytes (key, key_len, &alt_ctx, nss_alt_ctx); |
c3266dc0 UD |
208 | |
209 | /* Add salt. */ | |
ff886b82 | 210 | sha512_process_bytes (salt, salt_len, &alt_ctx, nss_alt_ctx); |
c3266dc0 UD |
211 | |
212 | /* Add key again. */ | |
ff886b82 | 213 | sha512_process_bytes (key, key_len, &alt_ctx, nss_alt_ctx); |
c3266dc0 UD |
214 | |
215 | /* Now get result of this (64 bytes) and add it to the other | |
216 | context. */ | |
ff886b82 | 217 | sha512_finish_ctx (&alt_ctx, nss_alt_ctx, alt_result); |
c3266dc0 UD |
218 | |
219 | /* Add for any character in the key one byte of the alternate sum. */ | |
220 | for (cnt = key_len; cnt > 64; cnt -= 64) | |
ff886b82 UD |
221 | sha512_process_bytes (alt_result, 64, &ctx, nss_ctx); |
222 | sha512_process_bytes (alt_result, cnt, &ctx, nss_ctx); | |
c3266dc0 UD |
223 | |
224 | /* Take the binary representation of the length of the key and for every | |
225 | 1 add the alternate sum, for every 0 the key. */ | |
226 | for (cnt = key_len; cnt > 0; cnt >>= 1) | |
227 | if ((cnt & 1) != 0) | |
ff886b82 | 228 | sha512_process_bytes (alt_result, 64, &ctx, nss_ctx); |
c3266dc0 | 229 | else |
ff886b82 | 230 | sha512_process_bytes (key, key_len, &ctx, nss_ctx); |
c3266dc0 UD |
231 | |
232 | /* Create intermediate result. */ | |
ff886b82 | 233 | sha512_finish_ctx (&ctx, nss_ctx, alt_result); |
c3266dc0 UD |
234 | |
235 | /* Start computation of P byte sequence. */ | |
ff886b82 | 236 | sha512_init_ctx (&alt_ctx, nss_alt_ctx); |
c3266dc0 UD |
237 | |
238 | /* For every character in the password add the entire password. */ | |
239 | for (cnt = 0; cnt < key_len; ++cnt) | |
ff886b82 | 240 | sha512_process_bytes (key, key_len, &alt_ctx, nss_alt_ctx); |
c3266dc0 UD |
241 | |
242 | /* Finish the digest. */ | |
ff886b82 | 243 | sha512_finish_ctx (&alt_ctx, nss_alt_ctx, temp_result); |
c3266dc0 UD |
244 | |
245 | /* Create byte sequence P. */ | |
b8dc394d JL |
246 | if (__libc_use_alloca (alloca_used + key_len)) |
247 | cp = p_bytes = (char *) alloca (key_len); | |
248 | else | |
249 | { | |
250 | free_pbytes = cp = p_bytes = (char *)malloc (key_len); | |
251 | if (free_pbytes == NULL) | |
252 | { | |
253 | free (free_key); | |
254 | return NULL; | |
255 | } | |
256 | } | |
257 | ||
c3266dc0 UD |
258 | for (cnt = key_len; cnt >= 64; cnt -= 64) |
259 | cp = mempcpy (cp, temp_result, 64); | |
260 | memcpy (cp, temp_result, cnt); | |
261 | ||
262 | /* Start computation of S byte sequence. */ | |
ff886b82 | 263 | sha512_init_ctx (&alt_ctx, nss_alt_ctx); |
c3266dc0 UD |
264 | |
265 | /* For every character in the password add the entire password. */ | |
266 | for (cnt = 0; cnt < 16 + alt_result[0]; ++cnt) | |
ff886b82 | 267 | sha512_process_bytes (salt, salt_len, &alt_ctx, nss_alt_ctx); |
c3266dc0 UD |
268 | |
269 | /* Finish the digest. */ | |
ff886b82 | 270 | sha512_finish_ctx (&alt_ctx, nss_alt_ctx, temp_result); |
c3266dc0 UD |
271 | |
272 | /* Create byte sequence S. */ | |
273 | cp = s_bytes = alloca (salt_len); | |
274 | for (cnt = salt_len; cnt >= 64; cnt -= 64) | |
275 | cp = mempcpy (cp, temp_result, 64); | |
276 | memcpy (cp, temp_result, cnt); | |
277 | ||
278 | /* Repeatedly run the collected hash value through SHA512 to burn | |
279 | CPU cycles. */ | |
280 | for (cnt = 0; cnt < rounds; ++cnt) | |
281 | { | |
282 | /* New context. */ | |
ff886b82 | 283 | sha512_init_ctx (&ctx, nss_ctx); |
c3266dc0 UD |
284 | |
285 | /* Add key or last result. */ | |
286 | if ((cnt & 1) != 0) | |
ff886b82 | 287 | sha512_process_bytes (p_bytes, key_len, &ctx, nss_ctx); |
c3266dc0 | 288 | else |
ff886b82 | 289 | sha512_process_bytes (alt_result, 64, &ctx, nss_ctx); |
c3266dc0 UD |
290 | |
291 | /* Add salt for numbers not divisible by 3. */ | |
292 | if (cnt % 3 != 0) | |
ff886b82 | 293 | sha512_process_bytes (s_bytes, salt_len, &ctx, nss_ctx); |
c3266dc0 UD |
294 | |
295 | /* Add key for numbers not divisible by 7. */ | |
296 | if (cnt % 7 != 0) | |
ff886b82 | 297 | sha512_process_bytes (p_bytes, key_len, &ctx, nss_ctx); |
c3266dc0 UD |
298 | |
299 | /* Add key or last result. */ | |
300 | if ((cnt & 1) != 0) | |
ff886b82 | 301 | sha512_process_bytes (alt_result, 64, &ctx, nss_ctx); |
c3266dc0 | 302 | else |
ff886b82 | 303 | sha512_process_bytes (p_bytes, key_len, &ctx, nss_ctx); |
c3266dc0 UD |
304 | |
305 | /* Create intermediate result. */ | |
ff886b82 | 306 | sha512_finish_ctx (&ctx, nss_ctx, alt_result); |
c3266dc0 UD |
307 | } |
308 | ||
ff886b82 UD |
309 | #ifdef USE_NSS |
310 | /* Free libfreebl3 resources. */ | |
311 | NSSLOW_Shutdown (nss_ictx); | |
312 | #endif | |
313 | ||
c3266dc0 UD |
314 | /* Now we can construct the result string. It consists of three |
315 | parts. */ | |
316 | cp = __stpncpy (buffer, sha512_salt_prefix, MAX (0, buflen)); | |
317 | buflen -= sizeof (sha512_salt_prefix) - 1; | |
318 | ||
319 | if (rounds_custom) | |
320 | { | |
61158ffa JM |
321 | int n = __snprintf (cp, MAX (0, buflen), "%s%zu$", |
322 | sha512_rounds_prefix, rounds); | |
c3266dc0 UD |
323 | cp += n; |
324 | buflen -= n; | |
325 | } | |
326 | ||
327 | cp = __stpncpy (cp, salt, MIN ((size_t) MAX (0, buflen), salt_len)); | |
328 | buflen -= MIN ((size_t) MAX (0, buflen), salt_len); | |
329 | ||
330 | if (buflen > 0) | |
331 | { | |
332 | *cp++ = '$'; | |
333 | --buflen; | |
334 | } | |
335 | ||
8747cd03 KS |
336 | __b64_from_24bit (&cp, &buflen, |
337 | alt_result[0], alt_result[21], alt_result[42], 4); | |
338 | __b64_from_24bit (&cp, &buflen, | |
339 | alt_result[22], alt_result[43], alt_result[1], 4); | |
340 | __b64_from_24bit (&cp, &buflen, | |
341 | alt_result[44], alt_result[2], alt_result[23], 4); | |
342 | __b64_from_24bit (&cp, &buflen, | |
343 | alt_result[3], alt_result[24], alt_result[45], 4); | |
344 | __b64_from_24bit (&cp, &buflen, | |
345 | alt_result[25], alt_result[46], alt_result[4], 4); | |
346 | __b64_from_24bit (&cp, &buflen, | |
347 | alt_result[47], alt_result[5], alt_result[26], 4); | |
348 | __b64_from_24bit (&cp, &buflen, | |
349 | alt_result[6], alt_result[27], alt_result[48], 4); | |
350 | __b64_from_24bit (&cp, &buflen, | |
351 | alt_result[28], alt_result[49], alt_result[7], 4); | |
352 | __b64_from_24bit (&cp, &buflen, | |
353 | alt_result[50], alt_result[8], alt_result[29], 4); | |
354 | __b64_from_24bit (&cp, &buflen, | |
355 | alt_result[9], alt_result[30], alt_result[51], 4); | |
356 | __b64_from_24bit (&cp, &buflen, | |
357 | alt_result[31], alt_result[52], alt_result[10], 4); | |
358 | __b64_from_24bit (&cp, &buflen, | |
359 | alt_result[53], alt_result[11], alt_result[32], 4); | |
360 | __b64_from_24bit (&cp, &buflen, | |
361 | alt_result[12], alt_result[33], alt_result[54], 4); | |
362 | __b64_from_24bit (&cp, &buflen, | |
363 | alt_result[34], alt_result[55], alt_result[13], 4); | |
364 | __b64_from_24bit (&cp, &buflen, | |
365 | alt_result[56], alt_result[14], alt_result[35], 4); | |
366 | __b64_from_24bit (&cp, &buflen, | |
367 | alt_result[15], alt_result[36], alt_result[57], 4); | |
368 | __b64_from_24bit (&cp, &buflen, | |
369 | alt_result[37], alt_result[58], alt_result[16], 4); | |
370 | __b64_from_24bit (&cp, &buflen, | |
371 | alt_result[59], alt_result[17], alt_result[38], 4); | |
372 | __b64_from_24bit (&cp, &buflen, | |
373 | alt_result[18], alt_result[39], alt_result[60], 4); | |
374 | __b64_from_24bit (&cp, &buflen, | |
375 | alt_result[40], alt_result[61], alt_result[19], 4); | |
376 | __b64_from_24bit (&cp, &buflen, | |
377 | alt_result[62], alt_result[20], alt_result[41], 4); | |
378 | __b64_from_24bit (&cp, &buflen, | |
379 | 0, 0, alt_result[63], 2); | |
c3266dc0 UD |
380 | |
381 | if (buflen <= 0) | |
382 | { | |
383 | __set_errno (ERANGE); | |
384 | buffer = NULL; | |
385 | } | |
386 | else | |
387 | *cp = '\0'; /* Terminate the string. */ | |
388 | ||
389 | /* Clear the buffer for the intermediate result so that people | |
390 | attaching to processes or reading core dumps cannot get any | |
391 | information. We do it in this way to clear correct_words[] | |
392 | inside the SHA512 implementation as well. */ | |
ff886b82 | 393 | #ifndef USE_NSS |
c3266dc0 UD |
394 | __sha512_init_ctx (&ctx); |
395 | __sha512_finish_ctx (&ctx, alt_result); | |
ea1bd74d ZW |
396 | explicit_bzero (&ctx, sizeof (ctx)); |
397 | explicit_bzero (&alt_ctx, sizeof (alt_ctx)); | |
ff886b82 | 398 | #endif |
ea1bd74d ZW |
399 | explicit_bzero (temp_result, sizeof (temp_result)); |
400 | explicit_bzero (p_bytes, key_len); | |
401 | explicit_bzero (s_bytes, salt_len); | |
c3266dc0 | 402 | if (copied_key != NULL) |
ea1bd74d | 403 | explicit_bzero (copied_key, key_len); |
c3266dc0 | 404 | if (copied_salt != NULL) |
ea1bd74d | 405 | explicit_bzero (copied_salt, salt_len); |
c3266dc0 | 406 | |
b8dc394d JL |
407 | free (free_key); |
408 | free (free_pbytes); | |
c3266dc0 UD |
409 | return buffer; |
410 | } | |
411 | ||
412 | #ifndef _LIBC | |
413 | # define libc_freeres_ptr(decl) decl | |
414 | #endif | |
415 | libc_freeres_ptr (static char *buffer); | |
416 | ||
417 | /* This entry point is equivalent to the `crypt' function in Unix | |
418 | libcs. */ | |
419 | char * | |
420 | __sha512_crypt (const char *key, const char *salt) | |
421 | { | |
422 | /* We don't want to have an arbitrary limit in the size of the | |
423 | password. We can compute an upper bound for the size of the | |
424 | result in advance and so we can prepare the buffer we pass to | |
425 | `sha512_crypt_r'. */ | |
426 | static int buflen; | |
427 | int needed = (sizeof (sha512_salt_prefix) - 1 | |
428 | + sizeof (sha512_rounds_prefix) + 9 + 1 | |
429 | + strlen (salt) + 1 + 86 + 1); | |
430 | ||
431 | if (buflen < needed) | |
432 | { | |
433 | char *new_buffer = (char *) realloc (buffer, needed); | |
434 | if (new_buffer == NULL) | |
435 | return NULL; | |
436 | ||
437 | buffer = new_buffer; | |
438 | buflen = needed; | |
439 | } | |
440 | ||
441 | return __sha512_crypt_r (key, salt, buffer, buflen); | |
442 | } | |
443 | ||
444 | #ifndef _LIBC | |
445 | static void | |
446 | __attribute__ ((__destructor__)) | |
447 | free_mem (void) | |
448 | { | |
449 | free (buffer); | |
450 | } | |
451 | #endif |