]>
Commit | Line | Data |
---|---|---|
1 | /* | |
2 | * DRBG: Deterministic Random Bits Generator | |
3 | * Based on NIST Recommended DRBG from NIST SP800-90A with the following | |
4 | * properties: | |
5 | * * CTR DRBG with DF with AES-128, AES-192, AES-256 cores | |
6 | * * Hash DRBG with DF with SHA-1, SHA-256, SHA-384, SHA-512 cores | |
7 | * * HMAC DRBG with DF with SHA-1, SHA-256, SHA-384, SHA-512 cores | |
8 | * * with and without prediction resistance | |
9 | * | |
10 | * Copyright Stephan Mueller <smueller@chronox.de>, 2014 | |
11 | * | |
12 | * Redistribution and use in source and binary forms, with or without | |
13 | * modification, are permitted provided that the following conditions | |
14 | * are met: | |
15 | * 1. Redistributions of source code must retain the above copyright | |
16 | * notice, and the entire permission notice in its entirety, | |
17 | * including the disclaimer of warranties. | |
18 | * 2. Redistributions in binary form must reproduce the above copyright | |
19 | * notice, this list of conditions and the following disclaimer in the | |
20 | * documentation and/or other materials provided with the distribution. | |
21 | * 3. The name of the author may not be used to endorse or promote | |
22 | * products derived from this software without specific prior | |
23 | * written permission. | |
24 | * | |
25 | * ALTERNATIVELY, this product may be distributed under the terms of | |
26 | * the GNU General Public License, in which case the provisions of the GPL are | |
27 | * required INSTEAD OF the above restrictions. (This clause is | |
28 | * necessary due to a potential bad interaction between the GPL and | |
29 | * the restrictions contained in a BSD-style copyright.) | |
30 | * | |
31 | * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED | |
32 | * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES | |
33 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, ALL OF | |
34 | * WHICH ARE HEREBY DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE | |
35 | * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR | |
36 | * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT | |
37 | * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR | |
38 | * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF | |
39 | * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT | |
40 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE | |
41 | * USE OF THIS SOFTWARE, EVEN IF NOT ADVISED OF THE POSSIBILITY OF SUCH | |
42 | * DAMAGE. | |
43 | * | |
44 | * DRBG Usage | |
45 | * ========== | |
46 | * The SP 800-90A DRBG allows the user to specify a personalization string | |
47 | * for initialization as well as an additional information string for each | |
48 | * random number request. The following code fragments show how a caller | |
49 | * uses the kernel crypto API to use the full functionality of the DRBG. | |
50 | * | |
51 | * Usage without any additional data | |
52 | * --------------------------------- | |
53 | * struct crypto_rng *drng; | |
54 | * int err; | |
55 | * char data[DATALEN]; | |
56 | * | |
57 | * drng = crypto_alloc_rng(drng_name, 0, 0); | |
58 | * err = crypto_rng_get_bytes(drng, &data, DATALEN); | |
59 | * crypto_free_rng(drng); | |
60 | * | |
61 | * | |
62 | * Usage with personalization string during initialization | |
63 | * ------------------------------------------------------- | |
64 | * struct crypto_rng *drng; | |
65 | * int err; | |
66 | * char data[DATALEN]; | |
67 | * struct drbg_string pers; | |
68 | * char personalization[11] = "some-string"; | |
69 | * | |
70 | * drbg_string_fill(&pers, personalization, strlen(personalization)); | |
71 | * drng = crypto_alloc_rng(drng_name, 0, 0); | |
72 | * // The reset completely re-initializes the DRBG with the provided | |
73 | * // personalization string | |
74 | * err = crypto_rng_reset(drng, &personalization, strlen(personalization)); | |
75 | * err = crypto_rng_get_bytes(drng, &data, DATALEN); | |
76 | * crypto_free_rng(drng); | |
77 | * | |
78 | * | |
79 | * Usage with additional information string during random number request | |
80 | * --------------------------------------------------------------------- | |
81 | * struct crypto_rng *drng; | |
82 | * int err; | |
83 | * char data[DATALEN]; | |
84 | * char addtl_string[11] = "some-string"; | |
85 | * string drbg_string addtl; | |
86 | * | |
87 | * drbg_string_fill(&addtl, addtl_string, strlen(addtl_string)); | |
88 | * drng = crypto_alloc_rng(drng_name, 0, 0); | |
89 | * // The following call is a wrapper to crypto_rng_get_bytes() and returns | |
90 | * // the same error codes. | |
91 | * err = crypto_drbg_get_bytes_addtl(drng, &data, DATALEN, &addtl); | |
92 | * crypto_free_rng(drng); | |
93 | * | |
94 | * | |
95 | * Usage with personalization and additional information strings | |
96 | * ------------------------------------------------------------- | |
97 | * Just mix both scenarios above. | |
98 | */ | |
99 | ||
100 | #include <crypto/drbg.h> | |
101 | ||
102 | /*************************************************************** | |
103 | * Backend cipher definitions available to DRBG | |
104 | ***************************************************************/ | |
105 | ||
106 | /* | |
107 | * The order of the DRBG definitions here matter: every DRBG is registered | |
108 | * as stdrng. Each DRBG receives an increasing cra_priority values the later | |
109 | * they are defined in this array (see drbg_fill_array). | |
110 | * | |
111 | * HMAC DRBGs are favored over Hash DRBGs over CTR DRBGs, and | |
112 | * the SHA256 / AES 256 over other ciphers. Thus, the favored | |
113 | * DRBGs are the latest entries in this array. | |
114 | */ | |
115 | static const struct drbg_core drbg_cores[] = { | |
116 | #ifdef CONFIG_CRYPTO_DRBG_CTR | |
117 | { | |
118 | .flags = DRBG_CTR | DRBG_STRENGTH128, | |
119 | .statelen = 32, /* 256 bits as defined in 10.2.1 */ | |
120 | .blocklen_bytes = 16, | |
121 | .cra_name = "ctr_aes128", | |
122 | .backend_cra_name = "aes", | |
123 | }, { | |
124 | .flags = DRBG_CTR | DRBG_STRENGTH192, | |
125 | .statelen = 40, /* 320 bits as defined in 10.2.1 */ | |
126 | .blocklen_bytes = 16, | |
127 | .cra_name = "ctr_aes192", | |
128 | .backend_cra_name = "aes", | |
129 | }, { | |
130 | .flags = DRBG_CTR | DRBG_STRENGTH256, | |
131 | .statelen = 48, /* 384 bits as defined in 10.2.1 */ | |
132 | .blocklen_bytes = 16, | |
133 | .cra_name = "ctr_aes256", | |
134 | .backend_cra_name = "aes", | |
135 | }, | |
136 | #endif /* CONFIG_CRYPTO_DRBG_CTR */ | |
137 | #ifdef CONFIG_CRYPTO_DRBG_HASH | |
138 | { | |
139 | .flags = DRBG_HASH | DRBG_STRENGTH128, | |
140 | .statelen = 55, /* 440 bits */ | |
141 | .blocklen_bytes = 20, | |
142 | .cra_name = "sha1", | |
143 | .backend_cra_name = "sha1", | |
144 | }, { | |
145 | .flags = DRBG_HASH | DRBG_STRENGTH256, | |
146 | .statelen = 111, /* 888 bits */ | |
147 | .blocklen_bytes = 48, | |
148 | .cra_name = "sha384", | |
149 | .backend_cra_name = "sha384", | |
150 | }, { | |
151 | .flags = DRBG_HASH | DRBG_STRENGTH256, | |
152 | .statelen = 111, /* 888 bits */ | |
153 | .blocklen_bytes = 64, | |
154 | .cra_name = "sha512", | |
155 | .backend_cra_name = "sha512", | |
156 | }, { | |
157 | .flags = DRBG_HASH | DRBG_STRENGTH256, | |
158 | .statelen = 55, /* 440 bits */ | |
159 | .blocklen_bytes = 32, | |
160 | .cra_name = "sha256", | |
161 | .backend_cra_name = "sha256", | |
162 | }, | |
163 | #endif /* CONFIG_CRYPTO_DRBG_HASH */ | |
164 | #ifdef CONFIG_CRYPTO_DRBG_HMAC | |
165 | { | |
166 | .flags = DRBG_HMAC | DRBG_STRENGTH128, | |
167 | .statelen = 20, /* block length of cipher */ | |
168 | .blocklen_bytes = 20, | |
169 | .cra_name = "hmac_sha1", | |
170 | .backend_cra_name = "hmac(sha1)", | |
171 | }, { | |
172 | .flags = DRBG_HMAC | DRBG_STRENGTH256, | |
173 | .statelen = 48, /* block length of cipher */ | |
174 | .blocklen_bytes = 48, | |
175 | .cra_name = "hmac_sha384", | |
176 | .backend_cra_name = "hmac(sha384)", | |
177 | }, { | |
178 | .flags = DRBG_HMAC | DRBG_STRENGTH256, | |
179 | .statelen = 64, /* block length of cipher */ | |
180 | .blocklen_bytes = 64, | |
181 | .cra_name = "hmac_sha512", | |
182 | .backend_cra_name = "hmac(sha512)", | |
183 | }, { | |
184 | .flags = DRBG_HMAC | DRBG_STRENGTH256, | |
185 | .statelen = 32, /* block length of cipher */ | |
186 | .blocklen_bytes = 32, | |
187 | .cra_name = "hmac_sha256", | |
188 | .backend_cra_name = "hmac(sha256)", | |
189 | }, | |
190 | #endif /* CONFIG_CRYPTO_DRBG_HMAC */ | |
191 | }; | |
192 | ||
193 | /****************************************************************** | |
194 | * Generic helper functions | |
195 | ******************************************************************/ | |
196 | ||
197 | /* | |
198 | * Return strength of DRBG according to SP800-90A section 8.4 | |
199 | * | |
200 | * @flags DRBG flags reference | |
201 | * | |
202 | * Return: normalized strength in *bytes* value or 32 as default | |
203 | * to counter programming errors | |
204 | */ | |
205 | static inline unsigned short drbg_sec_strength(drbg_flag_t flags) | |
206 | { | |
207 | switch (flags & DRBG_STRENGTH_MASK) { | |
208 | case DRBG_STRENGTH128: | |
209 | return 16; | |
210 | case DRBG_STRENGTH192: | |
211 | return 24; | |
212 | case DRBG_STRENGTH256: | |
213 | return 32; | |
214 | default: | |
215 | return 32; | |
216 | } | |
217 | } | |
218 | ||
219 | /* | |
220 | * FIPS 140-2 continuous self test | |
221 | * The test is performed on the result of one round of the output | |
222 | * function. Thus, the function implicitly knows the size of the | |
223 | * buffer. | |
224 | * | |
225 | * @drbg DRBG handle | |
226 | * @buf output buffer of random data to be checked | |
227 | * | |
228 | * return: | |
229 | * true on success | |
230 | * false on error | |
231 | */ | |
232 | static bool drbg_fips_continuous_test(struct drbg_state *drbg, | |
233 | const unsigned char *buf) | |
234 | { | |
235 | #ifdef CONFIG_CRYPTO_FIPS | |
236 | int ret = 0; | |
237 | /* skip test if we test the overall system */ | |
238 | if (list_empty(&drbg->test_data.list)) | |
239 | return true; | |
240 | /* only perform test in FIPS mode */ | |
241 | if (0 == fips_enabled) | |
242 | return true; | |
243 | if (!drbg->fips_primed) { | |
244 | /* Priming of FIPS test */ | |
245 | memcpy(drbg->prev, buf, drbg_blocklen(drbg)); | |
246 | drbg->fips_primed = true; | |
247 | /* return false due to priming, i.e. another round is needed */ | |
248 | return false; | |
249 | } | |
250 | ret = memcmp(drbg->prev, buf, drbg_blocklen(drbg)); | |
251 | if (!ret) | |
252 | panic("DRBG continuous self test failed\n"); | |
253 | memcpy(drbg->prev, buf, drbg_blocklen(drbg)); | |
254 | /* the test shall pass when the two compared values are not equal */ | |
255 | return ret != 0; | |
256 | #else | |
257 | return true; | |
258 | #endif /* CONFIG_CRYPTO_FIPS */ | |
259 | } | |
260 | ||
261 | /* | |
262 | * Convert an integer into a byte representation of this integer. | |
263 | * The byte representation is big-endian | |
264 | * | |
265 | * @val value to be converted | |
266 | * @buf buffer holding the converted integer -- caller must ensure that | |
267 | * buffer size is at least 32 bit | |
268 | */ | |
269 | #if (defined(CONFIG_CRYPTO_DRBG_HASH) || defined(CONFIG_CRYPTO_DRBG_CTR)) | |
270 | static inline void drbg_cpu_to_be32(__u32 val, unsigned char *buf) | |
271 | { | |
272 | struct s { | |
273 | __be32 conv; | |
274 | }; | |
275 | struct s *conversion = (struct s *) buf; | |
276 | ||
277 | conversion->conv = cpu_to_be32(val); | |
278 | } | |
279 | #endif /* defined(CONFIG_CRYPTO_DRBG_HASH) || defined(CONFIG_CRYPTO_DRBG_CTR) */ | |
280 | ||
281 | /****************************************************************** | |
282 | * CTR DRBG callback functions | |
283 | ******************************************************************/ | |
284 | ||
285 | #ifdef CONFIG_CRYPTO_DRBG_CTR | |
286 | #define CRYPTO_DRBG_CTR_STRING "CTR " | |
287 | MODULE_ALIAS_CRYPTO("drbg_pr_ctr_aes256"); | |
288 | MODULE_ALIAS_CRYPTO("drbg_nopr_ctr_aes256"); | |
289 | MODULE_ALIAS_CRYPTO("drbg_pr_ctr_aes192"); | |
290 | MODULE_ALIAS_CRYPTO("drbg_nopr_ctr_aes192"); | |
291 | MODULE_ALIAS_CRYPTO("drbg_pr_ctr_aes128"); | |
292 | MODULE_ALIAS_CRYPTO("drbg_nopr_ctr_aes128"); | |
293 | ||
294 | static int drbg_kcapi_sym(struct drbg_state *drbg, const unsigned char *key, | |
295 | unsigned char *outval, const struct drbg_string *in); | |
296 | static int drbg_init_sym_kernel(struct drbg_state *drbg); | |
297 | static int drbg_fini_sym_kernel(struct drbg_state *drbg); | |
298 | ||
299 | /* BCC function for CTR DRBG as defined in 10.4.3 */ | |
300 | static int drbg_ctr_bcc(struct drbg_state *drbg, | |
301 | unsigned char *out, const unsigned char *key, | |
302 | struct list_head *in) | |
303 | { | |
304 | int ret = 0; | |
305 | struct drbg_string *curr = NULL; | |
306 | struct drbg_string data; | |
307 | short cnt = 0; | |
308 | ||
309 | drbg_string_fill(&data, out, drbg_blocklen(drbg)); | |
310 | ||
311 | /* 10.4.3 step 2 / 4 */ | |
312 | list_for_each_entry(curr, in, list) { | |
313 | const unsigned char *pos = curr->buf; | |
314 | size_t len = curr->len; | |
315 | /* 10.4.3 step 4.1 */ | |
316 | while (len) { | |
317 | /* 10.4.3 step 4.2 */ | |
318 | if (drbg_blocklen(drbg) == cnt) { | |
319 | cnt = 0; | |
320 | ret = drbg_kcapi_sym(drbg, key, out, &data); | |
321 | if (ret) | |
322 | return ret; | |
323 | } | |
324 | out[cnt] ^= *pos; | |
325 | pos++; | |
326 | cnt++; | |
327 | len--; | |
328 | } | |
329 | } | |
330 | /* 10.4.3 step 4.2 for last block */ | |
331 | if (cnt) | |
332 | ret = drbg_kcapi_sym(drbg, key, out, &data); | |
333 | ||
334 | return ret; | |
335 | } | |
336 | ||
337 | /* | |
338 | * scratchpad usage: drbg_ctr_update is interlinked with drbg_ctr_df | |
339 | * (and drbg_ctr_bcc, but this function does not need any temporary buffers), | |
340 | * the scratchpad is used as follows: | |
341 | * drbg_ctr_update: | |
342 | * temp | |
343 | * start: drbg->scratchpad | |
344 | * length: drbg_statelen(drbg) + drbg_blocklen(drbg) | |
345 | * note: the cipher writing into this variable works | |
346 | * blocklen-wise. Now, when the statelen is not a multiple | |
347 | * of blocklen, the generateion loop below "spills over" | |
348 | * by at most blocklen. Thus, we need to give sufficient | |
349 | * memory. | |
350 | * df_data | |
351 | * start: drbg->scratchpad + | |
352 | * drbg_statelen(drbg) + drbg_blocklen(drbg) | |
353 | * length: drbg_statelen(drbg) | |
354 | * | |
355 | * drbg_ctr_df: | |
356 | * pad | |
357 | * start: df_data + drbg_statelen(drbg) | |
358 | * length: drbg_blocklen(drbg) | |
359 | * iv | |
360 | * start: pad + drbg_blocklen(drbg) | |
361 | * length: drbg_blocklen(drbg) | |
362 | * temp | |
363 | * start: iv + drbg_blocklen(drbg) | |
364 | * length: drbg_satelen(drbg) + drbg_blocklen(drbg) | |
365 | * note: temp is the buffer that the BCC function operates | |
366 | * on. BCC operates blockwise. drbg_statelen(drbg) | |
367 | * is sufficient when the DRBG state length is a multiple | |
368 | * of the block size. For AES192 (and maybe other ciphers) | |
369 | * this is not correct and the length for temp is | |
370 | * insufficient (yes, that also means for such ciphers, | |
371 | * the final output of all BCC rounds are truncated). | |
372 | * Therefore, add drbg_blocklen(drbg) to cover all | |
373 | * possibilities. | |
374 | */ | |
375 | ||
376 | /* Derivation Function for CTR DRBG as defined in 10.4.2 */ | |
377 | static int drbg_ctr_df(struct drbg_state *drbg, | |
378 | unsigned char *df_data, size_t bytes_to_return, | |
379 | struct list_head *seedlist) | |
380 | { | |
381 | int ret = -EFAULT; | |
382 | unsigned char L_N[8]; | |
383 | /* S3 is input */ | |
384 | struct drbg_string S1, S2, S4, cipherin; | |
385 | LIST_HEAD(bcc_list); | |
386 | unsigned char *pad = df_data + drbg_statelen(drbg); | |
387 | unsigned char *iv = pad + drbg_blocklen(drbg); | |
388 | unsigned char *temp = iv + drbg_blocklen(drbg); | |
389 | size_t padlen = 0; | |
390 | unsigned int templen = 0; | |
391 | /* 10.4.2 step 7 */ | |
392 | unsigned int i = 0; | |
393 | /* 10.4.2 step 8 */ | |
394 | const unsigned char *K = (unsigned char *) | |
395 | "\x00\x01\x02\x03\x04\x05\x06\x07" | |
396 | "\x08\x09\x0a\x0b\x0c\x0d\x0e\x0f" | |
397 | "\x10\x11\x12\x13\x14\x15\x16\x17" | |
398 | "\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f"; | |
399 | unsigned char *X; | |
400 | size_t generated_len = 0; | |
401 | size_t inputlen = 0; | |
402 | struct drbg_string *seed = NULL; | |
403 | ||
404 | memset(pad, 0, drbg_blocklen(drbg)); | |
405 | memset(iv, 0, drbg_blocklen(drbg)); | |
406 | ||
407 | /* 10.4.2 step 1 is implicit as we work byte-wise */ | |
408 | ||
409 | /* 10.4.2 step 2 */ | |
410 | if ((512/8) < bytes_to_return) | |
411 | return -EINVAL; | |
412 | ||
413 | /* 10.4.2 step 2 -- calculate the entire length of all input data */ | |
414 | list_for_each_entry(seed, seedlist, list) | |
415 | inputlen += seed->len; | |
416 | drbg_cpu_to_be32(inputlen, &L_N[0]); | |
417 | ||
418 | /* 10.4.2 step 3 */ | |
419 | drbg_cpu_to_be32(bytes_to_return, &L_N[4]); | |
420 | ||
421 | /* 10.4.2 step 5: length is L_N, input_string, one byte, padding */ | |
422 | padlen = (inputlen + sizeof(L_N) + 1) % (drbg_blocklen(drbg)); | |
423 | /* wrap the padlen appropriately */ | |
424 | if (padlen) | |
425 | padlen = drbg_blocklen(drbg) - padlen; | |
426 | /* | |
427 | * pad / padlen contains the 0x80 byte and the following zero bytes. | |
428 | * As the calculated padlen value only covers the number of zero | |
429 | * bytes, this value has to be incremented by one for the 0x80 byte. | |
430 | */ | |
431 | padlen++; | |
432 | pad[0] = 0x80; | |
433 | ||
434 | /* 10.4.2 step 4 -- first fill the linked list and then order it */ | |
435 | drbg_string_fill(&S1, iv, drbg_blocklen(drbg)); | |
436 | list_add_tail(&S1.list, &bcc_list); | |
437 | drbg_string_fill(&S2, L_N, sizeof(L_N)); | |
438 | list_add_tail(&S2.list, &bcc_list); | |
439 | list_splice_tail(seedlist, &bcc_list); | |
440 | drbg_string_fill(&S4, pad, padlen); | |
441 | list_add_tail(&S4.list, &bcc_list); | |
442 | ||
443 | /* 10.4.2 step 9 */ | |
444 | while (templen < (drbg_keylen(drbg) + (drbg_blocklen(drbg)))) { | |
445 | /* | |
446 | * 10.4.2 step 9.1 - the padding is implicit as the buffer | |
447 | * holds zeros after allocation -- even the increment of i | |
448 | * is irrelevant as the increment remains within length of i | |
449 | */ | |
450 | drbg_cpu_to_be32(i, iv); | |
451 | /* 10.4.2 step 9.2 -- BCC and concatenation with temp */ | |
452 | ret = drbg_ctr_bcc(drbg, temp + templen, K, &bcc_list); | |
453 | if (ret) | |
454 | goto out; | |
455 | /* 10.4.2 step 9.3 */ | |
456 | i++; | |
457 | templen += drbg_blocklen(drbg); | |
458 | } | |
459 | ||
460 | /* 10.4.2 step 11 */ | |
461 | X = temp + (drbg_keylen(drbg)); | |
462 | drbg_string_fill(&cipherin, X, drbg_blocklen(drbg)); | |
463 | ||
464 | /* 10.4.2 step 12: overwriting of outval is implemented in next step */ | |
465 | ||
466 | /* 10.4.2 step 13 */ | |
467 | while (generated_len < bytes_to_return) { | |
468 | short blocklen = 0; | |
469 | /* | |
470 | * 10.4.2 step 13.1: the truncation of the key length is | |
471 | * implicit as the key is only drbg_blocklen in size based on | |
472 | * the implementation of the cipher function callback | |
473 | */ | |
474 | ret = drbg_kcapi_sym(drbg, temp, X, &cipherin); | |
475 | if (ret) | |
476 | goto out; | |
477 | blocklen = (drbg_blocklen(drbg) < | |
478 | (bytes_to_return - generated_len)) ? | |
479 | drbg_blocklen(drbg) : | |
480 | (bytes_to_return - generated_len); | |
481 | /* 10.4.2 step 13.2 and 14 */ | |
482 | memcpy(df_data + generated_len, X, blocklen); | |
483 | generated_len += blocklen; | |
484 | } | |
485 | ||
486 | ret = 0; | |
487 | ||
488 | out: | |
489 | memset(iv, 0, drbg_blocklen(drbg)); | |
490 | memset(temp, 0, drbg_statelen(drbg) + drbg_blocklen(drbg)); | |
491 | memset(pad, 0, drbg_blocklen(drbg)); | |
492 | return ret; | |
493 | } | |
494 | ||
495 | /* | |
496 | * update function of CTR DRBG as defined in 10.2.1.2 | |
497 | * | |
498 | * The reseed variable has an enhanced meaning compared to the update | |
499 | * functions of the other DRBGs as follows: | |
500 | * 0 => initial seed from initialization | |
501 | * 1 => reseed via drbg_seed | |
502 | * 2 => first invocation from drbg_ctr_update when addtl is present. In | |
503 | * this case, the df_data scratchpad is not deleted so that it is | |
504 | * available for another calls to prevent calling the DF function | |
505 | * again. | |
506 | * 3 => second invocation from drbg_ctr_update. When the update function | |
507 | * was called with addtl, the df_data memory already contains the | |
508 | * DFed addtl information and we do not need to call DF again. | |
509 | */ | |
510 | static int drbg_ctr_update(struct drbg_state *drbg, struct list_head *seed, | |
511 | int reseed) | |
512 | { | |
513 | int ret = -EFAULT; | |
514 | /* 10.2.1.2 step 1 */ | |
515 | unsigned char *temp = drbg->scratchpad; | |
516 | unsigned char *df_data = drbg->scratchpad + drbg_statelen(drbg) + | |
517 | drbg_blocklen(drbg); | |
518 | unsigned char *temp_p, *df_data_p; /* pointer to iterate over buffers */ | |
519 | unsigned int len = 0; | |
520 | struct drbg_string cipherin; | |
521 | ||
522 | if (3 > reseed) | |
523 | memset(df_data, 0, drbg_statelen(drbg)); | |
524 | ||
525 | /* 10.2.1.3.2 step 2 and 10.2.1.4.2 step 2 */ | |
526 | if (seed) { | |
527 | ret = drbg_ctr_df(drbg, df_data, drbg_statelen(drbg), seed); | |
528 | if (ret) | |
529 | goto out; | |
530 | } | |
531 | ||
532 | drbg_string_fill(&cipherin, drbg->V, drbg_blocklen(drbg)); | |
533 | /* | |
534 | * 10.2.1.3.2 steps 2 and 3 are already covered as the allocation | |
535 | * zeroizes all memory during initialization | |
536 | */ | |
537 | while (len < (drbg_statelen(drbg))) { | |
538 | /* 10.2.1.2 step 2.1 */ | |
539 | crypto_inc(drbg->V, drbg_blocklen(drbg)); | |
540 | /* | |
541 | * 10.2.1.2 step 2.2 */ | |
542 | ret = drbg_kcapi_sym(drbg, drbg->C, temp + len, &cipherin); | |
543 | if (ret) | |
544 | goto out; | |
545 | /* 10.2.1.2 step 2.3 and 3 */ | |
546 | len += drbg_blocklen(drbg); | |
547 | } | |
548 | ||
549 | /* 10.2.1.2 step 4 */ | |
550 | temp_p = temp; | |
551 | df_data_p = df_data; | |
552 | for (len = 0; len < drbg_statelen(drbg); len++) { | |
553 | *temp_p ^= *df_data_p; | |
554 | df_data_p++; temp_p++; | |
555 | } | |
556 | ||
557 | /* 10.2.1.2 step 5 */ | |
558 | memcpy(drbg->C, temp, drbg_keylen(drbg)); | |
559 | /* 10.2.1.2 step 6 */ | |
560 | memcpy(drbg->V, temp + drbg_keylen(drbg), drbg_blocklen(drbg)); | |
561 | ret = 0; | |
562 | ||
563 | out: | |
564 | memset(temp, 0, drbg_statelen(drbg) + drbg_blocklen(drbg)); | |
565 | if (2 != reseed) | |
566 | memset(df_data, 0, drbg_statelen(drbg)); | |
567 | return ret; | |
568 | } | |
569 | ||
570 | /* | |
571 | * scratchpad use: drbg_ctr_update is called independently from | |
572 | * drbg_ctr_extract_bytes. Therefore, the scratchpad is reused | |
573 | */ | |
574 | /* Generate function of CTR DRBG as defined in 10.2.1.5.2 */ | |
575 | static int drbg_ctr_generate(struct drbg_state *drbg, | |
576 | unsigned char *buf, unsigned int buflen, | |
577 | struct list_head *addtl) | |
578 | { | |
579 | int len = 0; | |
580 | int ret = 0; | |
581 | struct drbg_string data; | |
582 | ||
583 | /* 10.2.1.5.2 step 2 */ | |
584 | if (addtl && !list_empty(addtl)) { | |
585 | ret = drbg_ctr_update(drbg, addtl, 2); | |
586 | if (ret) | |
587 | return 0; | |
588 | } | |
589 | ||
590 | /* 10.2.1.5.2 step 4.1 */ | |
591 | crypto_inc(drbg->V, drbg_blocklen(drbg)); | |
592 | drbg_string_fill(&data, drbg->V, drbg_blocklen(drbg)); | |
593 | while (len < buflen) { | |
594 | int outlen = 0; | |
595 | /* 10.2.1.5.2 step 4.2 */ | |
596 | ret = drbg_kcapi_sym(drbg, drbg->C, drbg->scratchpad, &data); | |
597 | if (ret) { | |
598 | len = ret; | |
599 | goto out; | |
600 | } | |
601 | outlen = (drbg_blocklen(drbg) < (buflen - len)) ? | |
602 | drbg_blocklen(drbg) : (buflen - len); | |
603 | if (!drbg_fips_continuous_test(drbg, drbg->scratchpad)) { | |
604 | /* 10.2.1.5.2 step 6 */ | |
605 | crypto_inc(drbg->V, drbg_blocklen(drbg)); | |
606 | continue; | |
607 | } | |
608 | /* 10.2.1.5.2 step 4.3 */ | |
609 | memcpy(buf + len, drbg->scratchpad, outlen); | |
610 | len += outlen; | |
611 | /* 10.2.1.5.2 step 6 */ | |
612 | if (len < buflen) | |
613 | crypto_inc(drbg->V, drbg_blocklen(drbg)); | |
614 | } | |
615 | ||
616 | /* 10.2.1.5.2 step 6 */ | |
617 | ret = drbg_ctr_update(drbg, NULL, 3); | |
618 | if (ret) | |
619 | len = ret; | |
620 | ||
621 | out: | |
622 | memset(drbg->scratchpad, 0, drbg_blocklen(drbg)); | |
623 | return len; | |
624 | } | |
625 | ||
626 | static struct drbg_state_ops drbg_ctr_ops = { | |
627 | .update = drbg_ctr_update, | |
628 | .generate = drbg_ctr_generate, | |
629 | .crypto_init = drbg_init_sym_kernel, | |
630 | .crypto_fini = drbg_fini_sym_kernel, | |
631 | }; | |
632 | #endif /* CONFIG_CRYPTO_DRBG_CTR */ | |
633 | ||
634 | /****************************************************************** | |
635 | * HMAC DRBG callback functions | |
636 | ******************************************************************/ | |
637 | ||
638 | #if defined(CONFIG_CRYPTO_DRBG_HASH) || defined(CONFIG_CRYPTO_DRBG_HMAC) | |
639 | static int drbg_kcapi_hash(struct drbg_state *drbg, const unsigned char *key, | |
640 | unsigned char *outval, const struct list_head *in); | |
641 | static int drbg_init_hash_kernel(struct drbg_state *drbg); | |
642 | static int drbg_fini_hash_kernel(struct drbg_state *drbg); | |
643 | #endif /* (CONFIG_CRYPTO_DRBG_HASH || CONFIG_CRYPTO_DRBG_HMAC) */ | |
644 | ||
645 | #ifdef CONFIG_CRYPTO_DRBG_HMAC | |
646 | #define CRYPTO_DRBG_HMAC_STRING "HMAC " | |
647 | MODULE_ALIAS_CRYPTO("drbg_pr_hmac_sha512"); | |
648 | MODULE_ALIAS_CRYPTO("drbg_nopr_hmac_sha512"); | |
649 | MODULE_ALIAS_CRYPTO("drbg_pr_hmac_sha384"); | |
650 | MODULE_ALIAS_CRYPTO("drbg_nopr_hmac_sha384"); | |
651 | MODULE_ALIAS_CRYPTO("drbg_pr_hmac_sha256"); | |
652 | MODULE_ALIAS_CRYPTO("drbg_nopr_hmac_sha256"); | |
653 | MODULE_ALIAS_CRYPTO("drbg_pr_hmac_sha1"); | |
654 | MODULE_ALIAS_CRYPTO("drbg_nopr_hmac_sha1"); | |
655 | ||
656 | /* update function of HMAC DRBG as defined in 10.1.2.2 */ | |
657 | static int drbg_hmac_update(struct drbg_state *drbg, struct list_head *seed, | |
658 | int reseed) | |
659 | { | |
660 | int ret = -EFAULT; | |
661 | int i = 0; | |
662 | struct drbg_string seed1, seed2, vdata; | |
663 | LIST_HEAD(seedlist); | |
664 | LIST_HEAD(vdatalist); | |
665 | ||
666 | if (!reseed) | |
667 | /* 10.1.2.3 step 2 -- memset(0) of C is implicit with kzalloc */ | |
668 | memset(drbg->V, 1, drbg_statelen(drbg)); | |
669 | ||
670 | drbg_string_fill(&seed1, drbg->V, drbg_statelen(drbg)); | |
671 | list_add_tail(&seed1.list, &seedlist); | |
672 | /* buffer of seed2 will be filled in for loop below with one byte */ | |
673 | drbg_string_fill(&seed2, NULL, 1); | |
674 | list_add_tail(&seed2.list, &seedlist); | |
675 | /* input data of seed is allowed to be NULL at this point */ | |
676 | if (seed) | |
677 | list_splice_tail(seed, &seedlist); | |
678 | ||
679 | drbg_string_fill(&vdata, drbg->V, drbg_statelen(drbg)); | |
680 | list_add_tail(&vdata.list, &vdatalist); | |
681 | for (i = 2; 0 < i; i--) { | |
682 | /* first round uses 0x0, second 0x1 */ | |
683 | unsigned char prefix = DRBG_PREFIX0; | |
684 | if (1 == i) | |
685 | prefix = DRBG_PREFIX1; | |
686 | /* 10.1.2.2 step 1 and 4 -- concatenation and HMAC for key */ | |
687 | seed2.buf = &prefix; | |
688 | ret = drbg_kcapi_hash(drbg, drbg->C, drbg->C, &seedlist); | |
689 | if (ret) | |
690 | return ret; | |
691 | ||
692 | /* 10.1.2.2 step 2 and 5 -- HMAC for V */ | |
693 | ret = drbg_kcapi_hash(drbg, drbg->C, drbg->V, &vdatalist); | |
694 | if (ret) | |
695 | return ret; | |
696 | ||
697 | /* 10.1.2.2 step 3 */ | |
698 | if (!seed) | |
699 | return ret; | |
700 | } | |
701 | ||
702 | return 0; | |
703 | } | |
704 | ||
705 | /* generate function of HMAC DRBG as defined in 10.1.2.5 */ | |
706 | static int drbg_hmac_generate(struct drbg_state *drbg, | |
707 | unsigned char *buf, | |
708 | unsigned int buflen, | |
709 | struct list_head *addtl) | |
710 | { | |
711 | int len = 0; | |
712 | int ret = 0; | |
713 | struct drbg_string data; | |
714 | LIST_HEAD(datalist); | |
715 | ||
716 | /* 10.1.2.5 step 2 */ | |
717 | if (addtl && !list_empty(addtl)) { | |
718 | ret = drbg_hmac_update(drbg, addtl, 1); | |
719 | if (ret) | |
720 | return ret; | |
721 | } | |
722 | ||
723 | drbg_string_fill(&data, drbg->V, drbg_statelen(drbg)); | |
724 | list_add_tail(&data.list, &datalist); | |
725 | while (len < buflen) { | |
726 | unsigned int outlen = 0; | |
727 | /* 10.1.2.5 step 4.1 */ | |
728 | ret = drbg_kcapi_hash(drbg, drbg->C, drbg->V, &datalist); | |
729 | if (ret) | |
730 | return ret; | |
731 | outlen = (drbg_blocklen(drbg) < (buflen - len)) ? | |
732 | drbg_blocklen(drbg) : (buflen - len); | |
733 | if (!drbg_fips_continuous_test(drbg, drbg->V)) | |
734 | continue; | |
735 | ||
736 | /* 10.1.2.5 step 4.2 */ | |
737 | memcpy(buf + len, drbg->V, outlen); | |
738 | len += outlen; | |
739 | } | |
740 | ||
741 | /* 10.1.2.5 step 6 */ | |
742 | if (addtl && !list_empty(addtl)) | |
743 | ret = drbg_hmac_update(drbg, addtl, 1); | |
744 | else | |
745 | ret = drbg_hmac_update(drbg, NULL, 1); | |
746 | if (ret) | |
747 | return ret; | |
748 | ||
749 | return len; | |
750 | } | |
751 | ||
752 | static struct drbg_state_ops drbg_hmac_ops = { | |
753 | .update = drbg_hmac_update, | |
754 | .generate = drbg_hmac_generate, | |
755 | .crypto_init = drbg_init_hash_kernel, | |
756 | .crypto_fini = drbg_fini_hash_kernel, | |
757 | }; | |
758 | #endif /* CONFIG_CRYPTO_DRBG_HMAC */ | |
759 | ||
760 | /****************************************************************** | |
761 | * Hash DRBG callback functions | |
762 | ******************************************************************/ | |
763 | ||
764 | #ifdef CONFIG_CRYPTO_DRBG_HASH | |
765 | #define CRYPTO_DRBG_HASH_STRING "HASH " | |
766 | MODULE_ALIAS_CRYPTO("drbg_pr_sha512"); | |
767 | MODULE_ALIAS_CRYPTO("drbg_nopr_sha512"); | |
768 | MODULE_ALIAS_CRYPTO("drbg_pr_sha384"); | |
769 | MODULE_ALIAS_CRYPTO("drbg_nopr_sha384"); | |
770 | MODULE_ALIAS_CRYPTO("drbg_pr_sha256"); | |
771 | MODULE_ALIAS_CRYPTO("drbg_nopr_sha256"); | |
772 | MODULE_ALIAS_CRYPTO("drbg_pr_sha1"); | |
773 | MODULE_ALIAS_CRYPTO("drbg_nopr_sha1"); | |
774 | ||
775 | /* | |
776 | * Increment buffer | |
777 | * | |
778 | * @dst buffer to increment | |
779 | * @add value to add | |
780 | */ | |
781 | static inline void drbg_add_buf(unsigned char *dst, size_t dstlen, | |
782 | const unsigned char *add, size_t addlen) | |
783 | { | |
784 | /* implied: dstlen > addlen */ | |
785 | unsigned char *dstptr; | |
786 | const unsigned char *addptr; | |
787 | unsigned int remainder = 0; | |
788 | size_t len = addlen; | |
789 | ||
790 | dstptr = dst + (dstlen-1); | |
791 | addptr = add + (addlen-1); | |
792 | while (len) { | |
793 | remainder += *dstptr + *addptr; | |
794 | *dstptr = remainder & 0xff; | |
795 | remainder >>= 8; | |
796 | len--; dstptr--; addptr--; | |
797 | } | |
798 | len = dstlen - addlen; | |
799 | while (len && remainder > 0) { | |
800 | remainder = *dstptr + 1; | |
801 | *dstptr = remainder & 0xff; | |
802 | remainder >>= 8; | |
803 | len--; dstptr--; | |
804 | } | |
805 | } | |
806 | ||
807 | /* | |
808 | * scratchpad usage: as drbg_hash_update and drbg_hash_df are used | |
809 | * interlinked, the scratchpad is used as follows: | |
810 | * drbg_hash_update | |
811 | * start: drbg->scratchpad | |
812 | * length: drbg_statelen(drbg) | |
813 | * drbg_hash_df: | |
814 | * start: drbg->scratchpad + drbg_statelen(drbg) | |
815 | * length: drbg_blocklen(drbg) | |
816 | * | |
817 | * drbg_hash_process_addtl uses the scratchpad, but fully completes | |
818 | * before either of the functions mentioned before are invoked. Therefore, | |
819 | * drbg_hash_process_addtl does not need to be specifically considered. | |
820 | */ | |
821 | ||
822 | /* Derivation Function for Hash DRBG as defined in 10.4.1 */ | |
823 | static int drbg_hash_df(struct drbg_state *drbg, | |
824 | unsigned char *outval, size_t outlen, | |
825 | struct list_head *entropylist) | |
826 | { | |
827 | int ret = 0; | |
828 | size_t len = 0; | |
829 | unsigned char input[5]; | |
830 | unsigned char *tmp = drbg->scratchpad + drbg_statelen(drbg); | |
831 | struct drbg_string data; | |
832 | ||
833 | /* 10.4.1 step 3 */ | |
834 | input[0] = 1; | |
835 | drbg_cpu_to_be32((outlen * 8), &input[1]); | |
836 | ||
837 | /* 10.4.1 step 4.1 -- concatenation of data for input into hash */ | |
838 | drbg_string_fill(&data, input, 5); | |
839 | list_add(&data.list, entropylist); | |
840 | ||
841 | /* 10.4.1 step 4 */ | |
842 | while (len < outlen) { | |
843 | short blocklen = 0; | |
844 | /* 10.4.1 step 4.1 */ | |
845 | ret = drbg_kcapi_hash(drbg, NULL, tmp, entropylist); | |
846 | if (ret) | |
847 | goto out; | |
848 | /* 10.4.1 step 4.2 */ | |
849 | input[0]++; | |
850 | blocklen = (drbg_blocklen(drbg) < (outlen - len)) ? | |
851 | drbg_blocklen(drbg) : (outlen - len); | |
852 | memcpy(outval + len, tmp, blocklen); | |
853 | len += blocklen; | |
854 | } | |
855 | ||
856 | out: | |
857 | memset(tmp, 0, drbg_blocklen(drbg)); | |
858 | return ret; | |
859 | } | |
860 | ||
861 | /* update function for Hash DRBG as defined in 10.1.1.2 / 10.1.1.3 */ | |
862 | static int drbg_hash_update(struct drbg_state *drbg, struct list_head *seed, | |
863 | int reseed) | |
864 | { | |
865 | int ret = 0; | |
866 | struct drbg_string data1, data2; | |
867 | LIST_HEAD(datalist); | |
868 | LIST_HEAD(datalist2); | |
869 | unsigned char *V = drbg->scratchpad; | |
870 | unsigned char prefix = DRBG_PREFIX1; | |
871 | ||
872 | if (!seed) | |
873 | return -EINVAL; | |
874 | ||
875 | if (reseed) { | |
876 | /* 10.1.1.3 step 1 */ | |
877 | memcpy(V, drbg->V, drbg_statelen(drbg)); | |
878 | drbg_string_fill(&data1, &prefix, 1); | |
879 | list_add_tail(&data1.list, &datalist); | |
880 | drbg_string_fill(&data2, V, drbg_statelen(drbg)); | |
881 | list_add_tail(&data2.list, &datalist); | |
882 | } | |
883 | list_splice_tail(seed, &datalist); | |
884 | ||
885 | /* 10.1.1.2 / 10.1.1.3 step 2 and 3 */ | |
886 | ret = drbg_hash_df(drbg, drbg->V, drbg_statelen(drbg), &datalist); | |
887 | if (ret) | |
888 | goto out; | |
889 | ||
890 | /* 10.1.1.2 / 10.1.1.3 step 4 */ | |
891 | prefix = DRBG_PREFIX0; | |
892 | drbg_string_fill(&data1, &prefix, 1); | |
893 | list_add_tail(&data1.list, &datalist2); | |
894 | drbg_string_fill(&data2, drbg->V, drbg_statelen(drbg)); | |
895 | list_add_tail(&data2.list, &datalist2); | |
896 | /* 10.1.1.2 / 10.1.1.3 step 4 */ | |
897 | ret = drbg_hash_df(drbg, drbg->C, drbg_statelen(drbg), &datalist2); | |
898 | ||
899 | out: | |
900 | memset(drbg->scratchpad, 0, drbg_statelen(drbg)); | |
901 | return ret; | |
902 | } | |
903 | ||
904 | /* processing of additional information string for Hash DRBG */ | |
905 | static int drbg_hash_process_addtl(struct drbg_state *drbg, | |
906 | struct list_head *addtl) | |
907 | { | |
908 | int ret = 0; | |
909 | struct drbg_string data1, data2; | |
910 | LIST_HEAD(datalist); | |
911 | unsigned char prefix = DRBG_PREFIX2; | |
912 | ||
913 | /* 10.1.1.4 step 2 */ | |
914 | if (!addtl || list_empty(addtl)) | |
915 | return 0; | |
916 | ||
917 | /* 10.1.1.4 step 2a */ | |
918 | drbg_string_fill(&data1, &prefix, 1); | |
919 | drbg_string_fill(&data2, drbg->V, drbg_statelen(drbg)); | |
920 | list_add_tail(&data1.list, &datalist); | |
921 | list_add_tail(&data2.list, &datalist); | |
922 | list_splice_tail(addtl, &datalist); | |
923 | ret = drbg_kcapi_hash(drbg, NULL, drbg->scratchpad, &datalist); | |
924 | if (ret) | |
925 | goto out; | |
926 | ||
927 | /* 10.1.1.4 step 2b */ | |
928 | drbg_add_buf(drbg->V, drbg_statelen(drbg), | |
929 | drbg->scratchpad, drbg_blocklen(drbg)); | |
930 | ||
931 | out: | |
932 | memset(drbg->scratchpad, 0, drbg_blocklen(drbg)); | |
933 | return ret; | |
934 | } | |
935 | ||
936 | /* Hashgen defined in 10.1.1.4 */ | |
937 | static int drbg_hash_hashgen(struct drbg_state *drbg, | |
938 | unsigned char *buf, | |
939 | unsigned int buflen) | |
940 | { | |
941 | int len = 0; | |
942 | int ret = 0; | |
943 | unsigned char *src = drbg->scratchpad; | |
944 | unsigned char *dst = drbg->scratchpad + drbg_statelen(drbg); | |
945 | struct drbg_string data; | |
946 | LIST_HEAD(datalist); | |
947 | ||
948 | /* 10.1.1.4 step hashgen 2 */ | |
949 | memcpy(src, drbg->V, drbg_statelen(drbg)); | |
950 | ||
951 | drbg_string_fill(&data, src, drbg_statelen(drbg)); | |
952 | list_add_tail(&data.list, &datalist); | |
953 | while (len < buflen) { | |
954 | unsigned int outlen = 0; | |
955 | /* 10.1.1.4 step hashgen 4.1 */ | |
956 | ret = drbg_kcapi_hash(drbg, NULL, dst, &datalist); | |
957 | if (ret) { | |
958 | len = ret; | |
959 | goto out; | |
960 | } | |
961 | outlen = (drbg_blocklen(drbg) < (buflen - len)) ? | |
962 | drbg_blocklen(drbg) : (buflen - len); | |
963 | if (!drbg_fips_continuous_test(drbg, dst)) { | |
964 | crypto_inc(src, drbg_statelen(drbg)); | |
965 | continue; | |
966 | } | |
967 | /* 10.1.1.4 step hashgen 4.2 */ | |
968 | memcpy(buf + len, dst, outlen); | |
969 | len += outlen; | |
970 | /* 10.1.1.4 hashgen step 4.3 */ | |
971 | if (len < buflen) | |
972 | crypto_inc(src, drbg_statelen(drbg)); | |
973 | } | |
974 | ||
975 | out: | |
976 | memset(drbg->scratchpad, 0, | |
977 | (drbg_statelen(drbg) + drbg_blocklen(drbg))); | |
978 | return len; | |
979 | } | |
980 | ||
981 | /* generate function for Hash DRBG as defined in 10.1.1.4 */ | |
982 | static int drbg_hash_generate(struct drbg_state *drbg, | |
983 | unsigned char *buf, unsigned int buflen, | |
984 | struct list_head *addtl) | |
985 | { | |
986 | int len = 0; | |
987 | int ret = 0; | |
988 | union { | |
989 | unsigned char req[8]; | |
990 | __be64 req_int; | |
991 | } u; | |
992 | unsigned char prefix = DRBG_PREFIX3; | |
993 | struct drbg_string data1, data2; | |
994 | LIST_HEAD(datalist); | |
995 | ||
996 | /* 10.1.1.4 step 2 */ | |
997 | ret = drbg_hash_process_addtl(drbg, addtl); | |
998 | if (ret) | |
999 | return ret; | |
1000 | /* 10.1.1.4 step 3 */ | |
1001 | len = drbg_hash_hashgen(drbg, buf, buflen); | |
1002 | ||
1003 | /* this is the value H as documented in 10.1.1.4 */ | |
1004 | /* 10.1.1.4 step 4 */ | |
1005 | drbg_string_fill(&data1, &prefix, 1); | |
1006 | list_add_tail(&data1.list, &datalist); | |
1007 | drbg_string_fill(&data2, drbg->V, drbg_statelen(drbg)); | |
1008 | list_add_tail(&data2.list, &datalist); | |
1009 | ret = drbg_kcapi_hash(drbg, NULL, drbg->scratchpad, &datalist); | |
1010 | if (ret) { | |
1011 | len = ret; | |
1012 | goto out; | |
1013 | } | |
1014 | ||
1015 | /* 10.1.1.4 step 5 */ | |
1016 | drbg_add_buf(drbg->V, drbg_statelen(drbg), | |
1017 | drbg->scratchpad, drbg_blocklen(drbg)); | |
1018 | drbg_add_buf(drbg->V, drbg_statelen(drbg), | |
1019 | drbg->C, drbg_statelen(drbg)); | |
1020 | u.req_int = cpu_to_be64(drbg->reseed_ctr); | |
1021 | drbg_add_buf(drbg->V, drbg_statelen(drbg), u.req, 8); | |
1022 | ||
1023 | out: | |
1024 | memset(drbg->scratchpad, 0, drbg_blocklen(drbg)); | |
1025 | return len; | |
1026 | } | |
1027 | ||
1028 | /* | |
1029 | * scratchpad usage: as update and generate are used isolated, both | |
1030 | * can use the scratchpad | |
1031 | */ | |
1032 | static struct drbg_state_ops drbg_hash_ops = { | |
1033 | .update = drbg_hash_update, | |
1034 | .generate = drbg_hash_generate, | |
1035 | .crypto_init = drbg_init_hash_kernel, | |
1036 | .crypto_fini = drbg_fini_hash_kernel, | |
1037 | }; | |
1038 | #endif /* CONFIG_CRYPTO_DRBG_HASH */ | |
1039 | ||
1040 | /****************************************************************** | |
1041 | * Functions common for DRBG implementations | |
1042 | ******************************************************************/ | |
1043 | ||
1044 | static inline int __drbg_seed(struct drbg_state *drbg, struct list_head *seed, | |
1045 | int reseed) | |
1046 | { | |
1047 | int ret = drbg->d_ops->update(drbg, seed, reseed); | |
1048 | ||
1049 | if (ret) | |
1050 | return ret; | |
1051 | ||
1052 | drbg->seeded = true; | |
1053 | /* 10.1.1.2 / 10.1.1.3 step 5 */ | |
1054 | drbg->reseed_ctr = 1; | |
1055 | ||
1056 | return ret; | |
1057 | } | |
1058 | ||
1059 | static void drbg_async_seed(struct work_struct *work) | |
1060 | { | |
1061 | struct drbg_string data; | |
1062 | LIST_HEAD(seedlist); | |
1063 | struct drbg_state *drbg = container_of(work, struct drbg_state, | |
1064 | seed_work); | |
1065 | ||
1066 | get_blocking_random_bytes(drbg->seed_buf, drbg->seed_buf_len); | |
1067 | ||
1068 | drbg_string_fill(&data, drbg->seed_buf, drbg->seed_buf_len); | |
1069 | list_add_tail(&data.list, &seedlist); | |
1070 | mutex_lock(&drbg->drbg_mutex); | |
1071 | __drbg_seed(drbg, &seedlist, true); | |
1072 | memzero_explicit(drbg->seed_buf, drbg->seed_buf_len); | |
1073 | mutex_unlock(&drbg->drbg_mutex); | |
1074 | } | |
1075 | ||
1076 | /* | |
1077 | * Seeding or reseeding of the DRBG | |
1078 | * | |
1079 | * @drbg: DRBG state struct | |
1080 | * @pers: personalization / additional information buffer | |
1081 | * @reseed: 0 for initial seed process, 1 for reseeding | |
1082 | * | |
1083 | * return: | |
1084 | * 0 on success | |
1085 | * error value otherwise | |
1086 | */ | |
1087 | static int drbg_seed(struct drbg_state *drbg, struct drbg_string *pers, | |
1088 | bool reseed) | |
1089 | { | |
1090 | int ret = 0; | |
1091 | struct drbg_string data1; | |
1092 | LIST_HEAD(seedlist); | |
1093 | ||
1094 | /* 9.1 / 9.2 / 9.3.1 step 3 */ | |
1095 | if (pers && pers->len > (drbg_max_addtl(drbg))) { | |
1096 | pr_devel("DRBG: personalization string too long %zu\n", | |
1097 | pers->len); | |
1098 | return -EINVAL; | |
1099 | } | |
1100 | ||
1101 | if (list_empty(&drbg->test_data.list)) { | |
1102 | drbg_string_fill(&data1, drbg->test_data.buf, | |
1103 | drbg->test_data.len); | |
1104 | pr_devel("DRBG: using test entropy\n"); | |
1105 | } else { | |
1106 | pr_devel("DRBG: (re)seeding with %zu bytes of entropy\n", | |
1107 | drbg->seed_buf_len); | |
1108 | get_random_bytes(drbg->seed_buf, drbg->seed_buf_len); | |
1109 | drbg_string_fill(&data1, drbg->seed_buf, drbg->seed_buf_len); | |
1110 | } | |
1111 | list_add_tail(&data1.list, &seedlist); | |
1112 | ||
1113 | /* | |
1114 | * concatenation of entropy with personalization str / addtl input) | |
1115 | * the variable pers is directly handed in by the caller, so check its | |
1116 | * contents whether it is appropriate | |
1117 | */ | |
1118 | if (pers && pers->buf && 0 < pers->len) { | |
1119 | list_add_tail(&pers->list, &seedlist); | |
1120 | pr_devel("DRBG: using personalization string\n"); | |
1121 | } | |
1122 | ||
1123 | if (!reseed) { | |
1124 | memset(drbg->V, 0, drbg_statelen(drbg)); | |
1125 | memset(drbg->C, 0, drbg_statelen(drbg)); | |
1126 | } | |
1127 | ||
1128 | ret = __drbg_seed(drbg, &seedlist, reseed); | |
1129 | ||
1130 | /* | |
1131 | * Clear the initial entropy buffer as the async call may not overwrite | |
1132 | * that buffer for quite some time. | |
1133 | */ | |
1134 | memzero_explicit(drbg->seed_buf, drbg->seed_buf_len); | |
1135 | if (ret) | |
1136 | goto out; | |
1137 | /* | |
1138 | * For all subsequent seeding calls, we only need the seed buffer | |
1139 | * equal to the security strength of the DRBG. We undo the calculation | |
1140 | * in drbg_alloc_state. | |
1141 | */ | |
1142 | if (!reseed) | |
1143 | drbg->seed_buf_len = drbg->seed_buf_len / 3 * 2; | |
1144 | ||
1145 | /* Invoke asynchronous seeding unless DRBG is in test mode. */ | |
1146 | if (!list_empty(&drbg->test_data.list) && !reseed) | |
1147 | schedule_work(&drbg->seed_work); | |
1148 | ||
1149 | out: | |
1150 | return ret; | |
1151 | } | |
1152 | ||
1153 | /* Free all substructures in a DRBG state without the DRBG state structure */ | |
1154 | static inline void drbg_dealloc_state(struct drbg_state *drbg) | |
1155 | { | |
1156 | if (!drbg) | |
1157 | return; | |
1158 | kzfree(drbg->V); | |
1159 | drbg->V = NULL; | |
1160 | kzfree(drbg->C); | |
1161 | drbg->C = NULL; | |
1162 | kzfree(drbg->scratchpad); | |
1163 | drbg->scratchpad = NULL; | |
1164 | drbg->reseed_ctr = 0; | |
1165 | drbg->d_ops = NULL; | |
1166 | drbg->core = NULL; | |
1167 | #ifdef CONFIG_CRYPTO_FIPS | |
1168 | kzfree(drbg->prev); | |
1169 | drbg->prev = NULL; | |
1170 | drbg->fips_primed = false; | |
1171 | #endif | |
1172 | kzfree(drbg->seed_buf); | |
1173 | drbg->seed_buf = NULL; | |
1174 | } | |
1175 | ||
1176 | /* | |
1177 | * Allocate all sub-structures for a DRBG state. | |
1178 | * The DRBG state structure must already be allocated. | |
1179 | */ | |
1180 | static inline int drbg_alloc_state(struct drbg_state *drbg) | |
1181 | { | |
1182 | int ret = -ENOMEM; | |
1183 | unsigned int sb_size = 0; | |
1184 | ||
1185 | switch (drbg->core->flags & DRBG_TYPE_MASK) { | |
1186 | #ifdef CONFIG_CRYPTO_DRBG_HMAC | |
1187 | case DRBG_HMAC: | |
1188 | drbg->d_ops = &drbg_hmac_ops; | |
1189 | break; | |
1190 | #endif /* CONFIG_CRYPTO_DRBG_HMAC */ | |
1191 | #ifdef CONFIG_CRYPTO_DRBG_HASH | |
1192 | case DRBG_HASH: | |
1193 | drbg->d_ops = &drbg_hash_ops; | |
1194 | break; | |
1195 | #endif /* CONFIG_CRYPTO_DRBG_HASH */ | |
1196 | #ifdef CONFIG_CRYPTO_DRBG_CTR | |
1197 | case DRBG_CTR: | |
1198 | drbg->d_ops = &drbg_ctr_ops; | |
1199 | break; | |
1200 | #endif /* CONFIG_CRYPTO_DRBG_CTR */ | |
1201 | default: | |
1202 | ret = -EOPNOTSUPP; | |
1203 | goto err; | |
1204 | } | |
1205 | ||
1206 | drbg->V = kmalloc(drbg_statelen(drbg), GFP_KERNEL); | |
1207 | if (!drbg->V) | |
1208 | goto err; | |
1209 | drbg->C = kmalloc(drbg_statelen(drbg), GFP_KERNEL); | |
1210 | if (!drbg->C) | |
1211 | goto err; | |
1212 | #ifdef CONFIG_CRYPTO_FIPS | |
1213 | drbg->prev = kmalloc(drbg_blocklen(drbg), GFP_KERNEL); | |
1214 | if (!drbg->prev) | |
1215 | goto err; | |
1216 | drbg->fips_primed = false; | |
1217 | #endif | |
1218 | /* scratchpad is only generated for CTR and Hash */ | |
1219 | if (drbg->core->flags & DRBG_HMAC) | |
1220 | sb_size = 0; | |
1221 | else if (drbg->core->flags & DRBG_CTR) | |
1222 | sb_size = drbg_statelen(drbg) + drbg_blocklen(drbg) + /* temp */ | |
1223 | drbg_statelen(drbg) + /* df_data */ | |
1224 | drbg_blocklen(drbg) + /* pad */ | |
1225 | drbg_blocklen(drbg) + /* iv */ | |
1226 | drbg_statelen(drbg) + drbg_blocklen(drbg); /* temp */ | |
1227 | else | |
1228 | sb_size = drbg_statelen(drbg) + drbg_blocklen(drbg); | |
1229 | ||
1230 | if (0 < sb_size) { | |
1231 | drbg->scratchpad = kzalloc(sb_size, GFP_KERNEL); | |
1232 | if (!drbg->scratchpad) | |
1233 | goto err; | |
1234 | } | |
1235 | ||
1236 | /* | |
1237 | * Gather entropy equal to the security strength of the DRBG. | |
1238 | * With a derivation function, a nonce is required in addition | |
1239 | * to the entropy. A nonce must be at least 1/2 of the security | |
1240 | * strength of the DRBG in size. Thus, entropy * nonce is 3/2 | |
1241 | * of the strength. The consideration of a nonce is only | |
1242 | * applicable during initial seeding. | |
1243 | */ | |
1244 | drbg->seed_buf_len = drbg_sec_strength(drbg->core->flags); | |
1245 | if (!drbg->seed_buf_len) { | |
1246 | ret = -EFAULT; | |
1247 | goto err; | |
1248 | } | |
1249 | /* ensure we have sufficient buffer space for initial seed */ | |
1250 | drbg->seed_buf_len = ((drbg->seed_buf_len + 1) / 2) * 3; | |
1251 | drbg->seed_buf = kzalloc(drbg->seed_buf_len, GFP_KERNEL); | |
1252 | if (!drbg->seed_buf) | |
1253 | goto err; | |
1254 | ||
1255 | INIT_WORK(&drbg->seed_work, drbg_async_seed); | |
1256 | ||
1257 | return 0; | |
1258 | ||
1259 | err: | |
1260 | drbg_dealloc_state(drbg); | |
1261 | return ret; | |
1262 | } | |
1263 | ||
1264 | /************************************************************************* | |
1265 | * DRBG interface functions | |
1266 | *************************************************************************/ | |
1267 | ||
1268 | /* | |
1269 | * DRBG generate function as required by SP800-90A - this function | |
1270 | * generates random numbers | |
1271 | * | |
1272 | * @drbg DRBG state handle | |
1273 | * @buf Buffer where to store the random numbers -- the buffer must already | |
1274 | * be pre-allocated by caller | |
1275 | * @buflen Length of output buffer - this value defines the number of random | |
1276 | * bytes pulled from DRBG | |
1277 | * @addtl Additional input that is mixed into state, may be NULL -- note | |
1278 | * the entropy is pulled by the DRBG internally unconditionally | |
1279 | * as defined in SP800-90A. The additional input is mixed into | |
1280 | * the state in addition to the pulled entropy. | |
1281 | * | |
1282 | * return: 0 when all bytes are generated; < 0 in case of an error | |
1283 | */ | |
1284 | static int drbg_generate(struct drbg_state *drbg, | |
1285 | unsigned char *buf, unsigned int buflen, | |
1286 | struct drbg_string *addtl) | |
1287 | { | |
1288 | int len = 0; | |
1289 | LIST_HEAD(addtllist); | |
1290 | ||
1291 | if (!drbg->core) { | |
1292 | pr_devel("DRBG: not yet seeded\n"); | |
1293 | return -EINVAL; | |
1294 | } | |
1295 | if (0 == buflen || !buf) { | |
1296 | pr_devel("DRBG: no output buffer provided\n"); | |
1297 | return -EINVAL; | |
1298 | } | |
1299 | if (addtl && NULL == addtl->buf && 0 < addtl->len) { | |
1300 | pr_devel("DRBG: wrong format of additional information\n"); | |
1301 | return -EINVAL; | |
1302 | } | |
1303 | ||
1304 | /* 9.3.1 step 2 */ | |
1305 | len = -EINVAL; | |
1306 | if (buflen > (drbg_max_request_bytes(drbg))) { | |
1307 | pr_devel("DRBG: requested random numbers too large %u\n", | |
1308 | buflen); | |
1309 | goto err; | |
1310 | } | |
1311 | ||
1312 | /* 9.3.1 step 3 is implicit with the chosen DRBG */ | |
1313 | ||
1314 | /* 9.3.1 step 4 */ | |
1315 | if (addtl && addtl->len > (drbg_max_addtl(drbg))) { | |
1316 | pr_devel("DRBG: additional information string too long %zu\n", | |
1317 | addtl->len); | |
1318 | goto err; | |
1319 | } | |
1320 | /* 9.3.1 step 5 is implicit with the chosen DRBG */ | |
1321 | ||
1322 | /* | |
1323 | * 9.3.1 step 6 and 9 supplemented by 9.3.2 step c is implemented | |
1324 | * here. The spec is a bit convoluted here, we make it simpler. | |
1325 | */ | |
1326 | if ((drbg_max_requests(drbg)) < drbg->reseed_ctr) | |
1327 | drbg->seeded = false; | |
1328 | ||
1329 | if (drbg->pr || !drbg->seeded) { | |
1330 | pr_devel("DRBG: reseeding before generation (prediction " | |
1331 | "resistance: %s, state %s)\n", | |
1332 | drbg->pr ? "true" : "false", | |
1333 | drbg->seeded ? "seeded" : "unseeded"); | |
1334 | /* 9.3.1 steps 7.1 through 7.3 */ | |
1335 | len = drbg_seed(drbg, addtl, true); | |
1336 | if (len) | |
1337 | goto err; | |
1338 | /* 9.3.1 step 7.4 */ | |
1339 | addtl = NULL; | |
1340 | } | |
1341 | ||
1342 | if (addtl && 0 < addtl->len) | |
1343 | list_add_tail(&addtl->list, &addtllist); | |
1344 | /* 9.3.1 step 8 and 10 */ | |
1345 | len = drbg->d_ops->generate(drbg, buf, buflen, &addtllist); | |
1346 | ||
1347 | /* 10.1.1.4 step 6, 10.1.2.5 step 7, 10.2.1.5.2 step 7 */ | |
1348 | drbg->reseed_ctr++; | |
1349 | if (0 >= len) | |
1350 | goto err; | |
1351 | ||
1352 | /* | |
1353 | * Section 11.3.3 requires to re-perform self tests after some | |
1354 | * generated random numbers. The chosen value after which self | |
1355 | * test is performed is arbitrary, but it should be reasonable. | |
1356 | * However, we do not perform the self tests because of the following | |
1357 | * reasons: it is mathematically impossible that the initial self tests | |
1358 | * were successfully and the following are not. If the initial would | |
1359 | * pass and the following would not, the kernel integrity is violated. | |
1360 | * In this case, the entire kernel operation is questionable and it | |
1361 | * is unlikely that the integrity violation only affects the | |
1362 | * correct operation of the DRBG. | |
1363 | * | |
1364 | * Albeit the following code is commented out, it is provided in | |
1365 | * case somebody has a need to implement the test of 11.3.3. | |
1366 | */ | |
1367 | #if 0 | |
1368 | if (drbg->reseed_ctr && !(drbg->reseed_ctr % 4096)) { | |
1369 | int err = 0; | |
1370 | pr_devel("DRBG: start to perform self test\n"); | |
1371 | if (drbg->core->flags & DRBG_HMAC) | |
1372 | err = alg_test("drbg_pr_hmac_sha256", | |
1373 | "drbg_pr_hmac_sha256", 0, 0); | |
1374 | else if (drbg->core->flags & DRBG_CTR) | |
1375 | err = alg_test("drbg_pr_ctr_aes128", | |
1376 | "drbg_pr_ctr_aes128", 0, 0); | |
1377 | else | |
1378 | err = alg_test("drbg_pr_sha256", | |
1379 | "drbg_pr_sha256", 0, 0); | |
1380 | if (err) { | |
1381 | pr_err("DRBG: periodical self test failed\n"); | |
1382 | /* | |
1383 | * uninstantiate implies that from now on, only errors | |
1384 | * are returned when reusing this DRBG cipher handle | |
1385 | */ | |
1386 | drbg_uninstantiate(drbg); | |
1387 | return 0; | |
1388 | } else { | |
1389 | pr_devel("DRBG: self test successful\n"); | |
1390 | } | |
1391 | } | |
1392 | #endif | |
1393 | ||
1394 | /* | |
1395 | * All operations were successful, return 0 as mandated by | |
1396 | * the kernel crypto API interface. | |
1397 | */ | |
1398 | len = 0; | |
1399 | err: | |
1400 | return len; | |
1401 | } | |
1402 | ||
1403 | /* | |
1404 | * Wrapper around drbg_generate which can pull arbitrary long strings | |
1405 | * from the DRBG without hitting the maximum request limitation. | |
1406 | * | |
1407 | * Parameters: see drbg_generate | |
1408 | * Return codes: see drbg_generate -- if one drbg_generate request fails, | |
1409 | * the entire drbg_generate_long request fails | |
1410 | */ | |
1411 | static int drbg_generate_long(struct drbg_state *drbg, | |
1412 | unsigned char *buf, unsigned int buflen, | |
1413 | struct drbg_string *addtl) | |
1414 | { | |
1415 | unsigned int len = 0; | |
1416 | unsigned int slice = 0; | |
1417 | do { | |
1418 | int err = 0; | |
1419 | unsigned int chunk = 0; | |
1420 | slice = ((buflen - len) / drbg_max_request_bytes(drbg)); | |
1421 | chunk = slice ? drbg_max_request_bytes(drbg) : (buflen - len); | |
1422 | mutex_lock(&drbg->drbg_mutex); | |
1423 | err = drbg_generate(drbg, buf + len, chunk, addtl); | |
1424 | mutex_unlock(&drbg->drbg_mutex); | |
1425 | if (0 > err) | |
1426 | return err; | |
1427 | len += chunk; | |
1428 | } while (slice > 0 && (len < buflen)); | |
1429 | return 0; | |
1430 | } | |
1431 | ||
1432 | /* | |
1433 | * DRBG instantiation function as required by SP800-90A - this function | |
1434 | * sets up the DRBG handle, performs the initial seeding and all sanity | |
1435 | * checks required by SP800-90A | |
1436 | * | |
1437 | * @drbg memory of state -- if NULL, new memory is allocated | |
1438 | * @pers Personalization string that is mixed into state, may be NULL -- note | |
1439 | * the entropy is pulled by the DRBG internally unconditionally | |
1440 | * as defined in SP800-90A. The additional input is mixed into | |
1441 | * the state in addition to the pulled entropy. | |
1442 | * @coreref reference to core | |
1443 | * @pr prediction resistance enabled | |
1444 | * | |
1445 | * return | |
1446 | * 0 on success | |
1447 | * error value otherwise | |
1448 | */ | |
1449 | static int drbg_instantiate(struct drbg_state *drbg, struct drbg_string *pers, | |
1450 | int coreref, bool pr) | |
1451 | { | |
1452 | int ret; | |
1453 | bool reseed = true; | |
1454 | ||
1455 | pr_devel("DRBG: Initializing DRBG core %d with prediction resistance " | |
1456 | "%s\n", coreref, pr ? "enabled" : "disabled"); | |
1457 | mutex_lock(&drbg->drbg_mutex); | |
1458 | ||
1459 | /* 9.1 step 1 is implicit with the selected DRBG type */ | |
1460 | ||
1461 | /* | |
1462 | * 9.1 step 2 is implicit as caller can select prediction resistance | |
1463 | * and the flag is copied into drbg->flags -- | |
1464 | * all DRBG types support prediction resistance | |
1465 | */ | |
1466 | ||
1467 | /* 9.1 step 4 is implicit in drbg_sec_strength */ | |
1468 | ||
1469 | if (!drbg->core) { | |
1470 | drbg->core = &drbg_cores[coreref]; | |
1471 | drbg->pr = pr; | |
1472 | drbg->seeded = false; | |
1473 | ||
1474 | ret = drbg_alloc_state(drbg); | |
1475 | if (ret) | |
1476 | goto unlock; | |
1477 | ||
1478 | ret = -EFAULT; | |
1479 | if (drbg->d_ops->crypto_init(drbg)) | |
1480 | goto err; | |
1481 | ||
1482 | reseed = false; | |
1483 | } | |
1484 | ||
1485 | ret = drbg_seed(drbg, pers, reseed); | |
1486 | ||
1487 | if (ret && !reseed) { | |
1488 | drbg->d_ops->crypto_fini(drbg); | |
1489 | goto err; | |
1490 | } | |
1491 | ||
1492 | mutex_unlock(&drbg->drbg_mutex); | |
1493 | return ret; | |
1494 | ||
1495 | err: | |
1496 | drbg_dealloc_state(drbg); | |
1497 | unlock: | |
1498 | mutex_unlock(&drbg->drbg_mutex); | |
1499 | return ret; | |
1500 | } | |
1501 | ||
1502 | /* | |
1503 | * DRBG uninstantiate function as required by SP800-90A - this function | |
1504 | * frees all buffers and the DRBG handle | |
1505 | * | |
1506 | * @drbg DRBG state handle | |
1507 | * | |
1508 | * return | |
1509 | * 0 on success | |
1510 | */ | |
1511 | static int drbg_uninstantiate(struct drbg_state *drbg) | |
1512 | { | |
1513 | cancel_work_sync(&drbg->seed_work); | |
1514 | if (drbg->d_ops) | |
1515 | drbg->d_ops->crypto_fini(drbg); | |
1516 | drbg_dealloc_state(drbg); | |
1517 | /* no scrubbing of test_data -- this shall survive an uninstantiate */ | |
1518 | return 0; | |
1519 | } | |
1520 | ||
1521 | /* | |
1522 | * Helper function for setting the test data in the DRBG | |
1523 | * | |
1524 | * @drbg DRBG state handle | |
1525 | * @data test data | |
1526 | * @len test data length | |
1527 | */ | |
1528 | static void drbg_kcapi_set_entropy(struct crypto_rng *tfm, | |
1529 | const u8 *data, unsigned int len) | |
1530 | { | |
1531 | struct drbg_state *drbg = crypto_rng_ctx(tfm); | |
1532 | ||
1533 | mutex_lock(&drbg->drbg_mutex); | |
1534 | drbg_string_fill(&drbg->test_data, data, len); | |
1535 | mutex_unlock(&drbg->drbg_mutex); | |
1536 | } | |
1537 | ||
1538 | /*************************************************************** | |
1539 | * Kernel crypto API cipher invocations requested by DRBG | |
1540 | ***************************************************************/ | |
1541 | ||
1542 | #if defined(CONFIG_CRYPTO_DRBG_HASH) || defined(CONFIG_CRYPTO_DRBG_HMAC) | |
1543 | struct sdesc { | |
1544 | struct shash_desc shash; | |
1545 | char ctx[]; | |
1546 | }; | |
1547 | ||
1548 | static int drbg_init_hash_kernel(struct drbg_state *drbg) | |
1549 | { | |
1550 | struct sdesc *sdesc; | |
1551 | struct crypto_shash *tfm; | |
1552 | ||
1553 | tfm = crypto_alloc_shash(drbg->core->backend_cra_name, 0, 0); | |
1554 | if (IS_ERR(tfm)) { | |
1555 | pr_info("DRBG: could not allocate digest TFM handle\n"); | |
1556 | return PTR_ERR(tfm); | |
1557 | } | |
1558 | BUG_ON(drbg_blocklen(drbg) != crypto_shash_digestsize(tfm)); | |
1559 | sdesc = kzalloc(sizeof(struct shash_desc) + crypto_shash_descsize(tfm), | |
1560 | GFP_KERNEL); | |
1561 | if (!sdesc) { | |
1562 | crypto_free_shash(tfm); | |
1563 | return -ENOMEM; | |
1564 | } | |
1565 | ||
1566 | sdesc->shash.tfm = tfm; | |
1567 | sdesc->shash.flags = 0; | |
1568 | drbg->priv_data = sdesc; | |
1569 | return 0; | |
1570 | } | |
1571 | ||
1572 | static int drbg_fini_hash_kernel(struct drbg_state *drbg) | |
1573 | { | |
1574 | struct sdesc *sdesc = (struct sdesc *)drbg->priv_data; | |
1575 | if (sdesc) { | |
1576 | crypto_free_shash(sdesc->shash.tfm); | |
1577 | kzfree(sdesc); | |
1578 | } | |
1579 | drbg->priv_data = NULL; | |
1580 | return 0; | |
1581 | } | |
1582 | ||
1583 | static int drbg_kcapi_hash(struct drbg_state *drbg, const unsigned char *key, | |
1584 | unsigned char *outval, const struct list_head *in) | |
1585 | { | |
1586 | struct sdesc *sdesc = (struct sdesc *)drbg->priv_data; | |
1587 | struct drbg_string *input = NULL; | |
1588 | ||
1589 | if (key) | |
1590 | crypto_shash_setkey(sdesc->shash.tfm, key, drbg_statelen(drbg)); | |
1591 | crypto_shash_init(&sdesc->shash); | |
1592 | list_for_each_entry(input, in, list) | |
1593 | crypto_shash_update(&sdesc->shash, input->buf, input->len); | |
1594 | return crypto_shash_final(&sdesc->shash, outval); | |
1595 | } | |
1596 | #endif /* (CONFIG_CRYPTO_DRBG_HASH || CONFIG_CRYPTO_DRBG_HMAC) */ | |
1597 | ||
1598 | #ifdef CONFIG_CRYPTO_DRBG_CTR | |
1599 | static int drbg_init_sym_kernel(struct drbg_state *drbg) | |
1600 | { | |
1601 | int ret = 0; | |
1602 | struct crypto_cipher *tfm; | |
1603 | ||
1604 | tfm = crypto_alloc_cipher(drbg->core->backend_cra_name, 0, 0); | |
1605 | if (IS_ERR(tfm)) { | |
1606 | pr_info("DRBG: could not allocate cipher TFM handle\n"); | |
1607 | return PTR_ERR(tfm); | |
1608 | } | |
1609 | BUG_ON(drbg_blocklen(drbg) != crypto_cipher_blocksize(tfm)); | |
1610 | drbg->priv_data = tfm; | |
1611 | return ret; | |
1612 | } | |
1613 | ||
1614 | static int drbg_fini_sym_kernel(struct drbg_state *drbg) | |
1615 | { | |
1616 | struct crypto_cipher *tfm = | |
1617 | (struct crypto_cipher *)drbg->priv_data; | |
1618 | if (tfm) | |
1619 | crypto_free_cipher(tfm); | |
1620 | drbg->priv_data = NULL; | |
1621 | return 0; | |
1622 | } | |
1623 | ||
1624 | static int drbg_kcapi_sym(struct drbg_state *drbg, const unsigned char *key, | |
1625 | unsigned char *outval, const struct drbg_string *in) | |
1626 | { | |
1627 | struct crypto_cipher *tfm = | |
1628 | (struct crypto_cipher *)drbg->priv_data; | |
1629 | ||
1630 | crypto_cipher_setkey(tfm, key, (drbg_keylen(drbg))); | |
1631 | /* there is only component in *in */ | |
1632 | BUG_ON(in->len < drbg_blocklen(drbg)); | |
1633 | crypto_cipher_encrypt_one(tfm, outval, in->buf); | |
1634 | return 0; | |
1635 | } | |
1636 | #endif /* CONFIG_CRYPTO_DRBG_CTR */ | |
1637 | ||
1638 | /*************************************************************** | |
1639 | * Kernel crypto API interface to register DRBG | |
1640 | ***************************************************************/ | |
1641 | ||
1642 | /* | |
1643 | * Look up the DRBG flags by given kernel crypto API cra_name | |
1644 | * The code uses the drbg_cores definition to do this | |
1645 | * | |
1646 | * @cra_name kernel crypto API cra_name | |
1647 | * @coreref reference to integer which is filled with the pointer to | |
1648 | * the applicable core | |
1649 | * @pr reference for setting prediction resistance | |
1650 | * | |
1651 | * return: flags | |
1652 | */ | |
1653 | static inline void drbg_convert_tfm_core(const char *cra_driver_name, | |
1654 | int *coreref, bool *pr) | |
1655 | { | |
1656 | int i = 0; | |
1657 | size_t start = 0; | |
1658 | int len = 0; | |
1659 | ||
1660 | *pr = true; | |
1661 | /* disassemble the names */ | |
1662 | if (!memcmp(cra_driver_name, "drbg_nopr_", 10)) { | |
1663 | start = 10; | |
1664 | *pr = false; | |
1665 | } else if (!memcmp(cra_driver_name, "drbg_pr_", 8)) { | |
1666 | start = 8; | |
1667 | } else { | |
1668 | return; | |
1669 | } | |
1670 | ||
1671 | /* remove the first part */ | |
1672 | len = strlen(cra_driver_name) - start; | |
1673 | for (i = 0; ARRAY_SIZE(drbg_cores) > i; i++) { | |
1674 | if (!memcmp(cra_driver_name + start, drbg_cores[i].cra_name, | |
1675 | len)) { | |
1676 | *coreref = i; | |
1677 | return; | |
1678 | } | |
1679 | } | |
1680 | } | |
1681 | ||
1682 | static int drbg_kcapi_init(struct crypto_tfm *tfm) | |
1683 | { | |
1684 | struct drbg_state *drbg = crypto_tfm_ctx(tfm); | |
1685 | ||
1686 | mutex_init(&drbg->drbg_mutex); | |
1687 | ||
1688 | return 0; | |
1689 | } | |
1690 | ||
1691 | static void drbg_kcapi_cleanup(struct crypto_tfm *tfm) | |
1692 | { | |
1693 | drbg_uninstantiate(crypto_tfm_ctx(tfm)); | |
1694 | } | |
1695 | ||
1696 | /* | |
1697 | * Generate random numbers invoked by the kernel crypto API: | |
1698 | * The API of the kernel crypto API is extended as follows: | |
1699 | * | |
1700 | * src is additional input supplied to the RNG. | |
1701 | * slen is the length of src. | |
1702 | * dst is the output buffer where random data is to be stored. | |
1703 | * dlen is the length of dst. | |
1704 | */ | |
1705 | static int drbg_kcapi_random(struct crypto_rng *tfm, | |
1706 | const u8 *src, unsigned int slen, | |
1707 | u8 *dst, unsigned int dlen) | |
1708 | { | |
1709 | struct drbg_state *drbg = crypto_rng_ctx(tfm); | |
1710 | struct drbg_string *addtl = NULL; | |
1711 | struct drbg_string string; | |
1712 | ||
1713 | if (slen) { | |
1714 | /* linked list variable is now local to allow modification */ | |
1715 | drbg_string_fill(&string, src, slen); | |
1716 | addtl = &string; | |
1717 | } | |
1718 | ||
1719 | return drbg_generate_long(drbg, dst, dlen, addtl); | |
1720 | } | |
1721 | ||
1722 | /* | |
1723 | * Seed the DRBG invoked by the kernel crypto API | |
1724 | */ | |
1725 | static int drbg_kcapi_seed(struct crypto_rng *tfm, | |
1726 | const u8 *seed, unsigned int slen) | |
1727 | { | |
1728 | struct drbg_state *drbg = crypto_rng_ctx(tfm); | |
1729 | struct crypto_tfm *tfm_base = crypto_rng_tfm(tfm); | |
1730 | bool pr = false; | |
1731 | struct drbg_string string; | |
1732 | struct drbg_string *seed_string = NULL; | |
1733 | int coreref = 0; | |
1734 | ||
1735 | drbg_convert_tfm_core(crypto_tfm_alg_driver_name(tfm_base), &coreref, | |
1736 | &pr); | |
1737 | if (0 < slen) { | |
1738 | drbg_string_fill(&string, seed, slen); | |
1739 | seed_string = &string; | |
1740 | } | |
1741 | ||
1742 | return drbg_instantiate(drbg, seed_string, coreref, pr); | |
1743 | } | |
1744 | ||
1745 | /*************************************************************** | |
1746 | * Kernel module: code to load the module | |
1747 | ***************************************************************/ | |
1748 | ||
1749 | /* | |
1750 | * Tests as defined in 11.3.2 in addition to the cipher tests: testing | |
1751 | * of the error handling. | |
1752 | * | |
1753 | * Note: testing of failing seed source as defined in 11.3.2 is not applicable | |
1754 | * as seed source of get_random_bytes does not fail. | |
1755 | * | |
1756 | * Note 2: There is no sensible way of testing the reseed counter | |
1757 | * enforcement, so skip it. | |
1758 | */ | |
1759 | static inline int __init drbg_healthcheck_sanity(void) | |
1760 | { | |
1761 | int len = 0; | |
1762 | #define OUTBUFLEN 16 | |
1763 | unsigned char buf[OUTBUFLEN]; | |
1764 | struct drbg_state *drbg = NULL; | |
1765 | int ret = -EFAULT; | |
1766 | int rc = -EFAULT; | |
1767 | bool pr = false; | |
1768 | int coreref = 0; | |
1769 | struct drbg_string addtl; | |
1770 | size_t max_addtllen, max_request_bytes; | |
1771 | ||
1772 | /* only perform test in FIPS mode */ | |
1773 | if (!fips_enabled) | |
1774 | return 0; | |
1775 | ||
1776 | #ifdef CONFIG_CRYPTO_DRBG_CTR | |
1777 | drbg_convert_tfm_core("drbg_nopr_ctr_aes128", &coreref, &pr); | |
1778 | #elif defined CONFIG_CRYPTO_DRBG_HASH | |
1779 | drbg_convert_tfm_core("drbg_nopr_sha256", &coreref, &pr); | |
1780 | #else | |
1781 | drbg_convert_tfm_core("drbg_nopr_hmac_sha256", &coreref, &pr); | |
1782 | #endif | |
1783 | ||
1784 | drbg = kzalloc(sizeof(struct drbg_state), GFP_KERNEL); | |
1785 | if (!drbg) | |
1786 | return -ENOMEM; | |
1787 | ||
1788 | mutex_init(&drbg->drbg_mutex); | |
1789 | ||
1790 | /* | |
1791 | * if the following tests fail, it is likely that there is a buffer | |
1792 | * overflow as buf is much smaller than the requested or provided | |
1793 | * string lengths -- in case the error handling does not succeed | |
1794 | * we may get an OOPS. And we want to get an OOPS as this is a | |
1795 | * grave bug. | |
1796 | */ | |
1797 | ||
1798 | /* get a valid instance of DRBG for following tests */ | |
1799 | ret = drbg_instantiate(drbg, NULL, coreref, pr); | |
1800 | if (ret) { | |
1801 | rc = ret; | |
1802 | goto outbuf; | |
1803 | } | |
1804 | max_addtllen = drbg_max_addtl(drbg); | |
1805 | max_request_bytes = drbg_max_request_bytes(drbg); | |
1806 | drbg_string_fill(&addtl, buf, max_addtllen + 1); | |
1807 | /* overflow addtllen with additonal info string */ | |
1808 | len = drbg_generate(drbg, buf, OUTBUFLEN, &addtl); | |
1809 | BUG_ON(0 < len); | |
1810 | /* overflow max_bits */ | |
1811 | len = drbg_generate(drbg, buf, (max_request_bytes + 1), NULL); | |
1812 | BUG_ON(0 < len); | |
1813 | drbg_uninstantiate(drbg); | |
1814 | ||
1815 | /* overflow max addtllen with personalization string */ | |
1816 | ret = drbg_instantiate(drbg, &addtl, coreref, pr); | |
1817 | BUG_ON(0 == ret); | |
1818 | /* all tests passed */ | |
1819 | rc = 0; | |
1820 | ||
1821 | pr_devel("DRBG: Sanity tests for failure code paths successfully " | |
1822 | "completed\n"); | |
1823 | ||
1824 | drbg_uninstantiate(drbg); | |
1825 | outbuf: | |
1826 | kzfree(drbg); | |
1827 | return rc; | |
1828 | } | |
1829 | ||
1830 | static struct rng_alg drbg_algs[22]; | |
1831 | ||
1832 | /* | |
1833 | * Fill the array drbg_algs used to register the different DRBGs | |
1834 | * with the kernel crypto API. To fill the array, the information | |
1835 | * from drbg_cores[] is used. | |
1836 | */ | |
1837 | static inline void __init drbg_fill_array(struct rng_alg *alg, | |
1838 | const struct drbg_core *core, int pr) | |
1839 | { | |
1840 | int pos = 0; | |
1841 | static int priority = 100; | |
1842 | ||
1843 | memcpy(alg->base.cra_name, "stdrng", 6); | |
1844 | if (pr) { | |
1845 | memcpy(alg->base.cra_driver_name, "drbg_pr_", 8); | |
1846 | pos = 8; | |
1847 | } else { | |
1848 | memcpy(alg->base.cra_driver_name, "drbg_nopr_", 10); | |
1849 | pos = 10; | |
1850 | } | |
1851 | memcpy(alg->base.cra_driver_name + pos, core->cra_name, | |
1852 | strlen(core->cra_name)); | |
1853 | ||
1854 | alg->base.cra_priority = priority; | |
1855 | priority++; | |
1856 | /* | |
1857 | * If FIPS mode enabled, the selected DRBG shall have the | |
1858 | * highest cra_priority over other stdrng instances to ensure | |
1859 | * it is selected. | |
1860 | */ | |
1861 | if (fips_enabled) | |
1862 | alg->base.cra_priority += 200; | |
1863 | ||
1864 | alg->base.cra_ctxsize = sizeof(struct drbg_state); | |
1865 | alg->base.cra_module = THIS_MODULE; | |
1866 | alg->base.cra_init = drbg_kcapi_init; | |
1867 | alg->base.cra_exit = drbg_kcapi_cleanup; | |
1868 | alg->generate = drbg_kcapi_random; | |
1869 | alg->seed = drbg_kcapi_seed; | |
1870 | alg->set_ent = drbg_kcapi_set_entropy; | |
1871 | alg->seedsize = 0; | |
1872 | } | |
1873 | ||
1874 | static int __init drbg_init(void) | |
1875 | { | |
1876 | unsigned int i = 0; /* pointer to drbg_algs */ | |
1877 | unsigned int j = 0; /* pointer to drbg_cores */ | |
1878 | int ret = -EFAULT; | |
1879 | ||
1880 | ret = drbg_healthcheck_sanity(); | |
1881 | if (ret) | |
1882 | return ret; | |
1883 | ||
1884 | if (ARRAY_SIZE(drbg_cores) * 2 > ARRAY_SIZE(drbg_algs)) { | |
1885 | pr_info("DRBG: Cannot register all DRBG types" | |
1886 | "(slots needed: %zu, slots available: %zu)\n", | |
1887 | ARRAY_SIZE(drbg_cores) * 2, ARRAY_SIZE(drbg_algs)); | |
1888 | return ret; | |
1889 | } | |
1890 | ||
1891 | /* | |
1892 | * each DRBG definition can be used with PR and without PR, thus | |
1893 | * we instantiate each DRBG in drbg_cores[] twice. | |
1894 | * | |
1895 | * As the order of placing them into the drbg_algs array matters | |
1896 | * (the later DRBGs receive a higher cra_priority) we register the | |
1897 | * prediction resistance DRBGs first as the should not be too | |
1898 | * interesting. | |
1899 | */ | |
1900 | for (j = 0; ARRAY_SIZE(drbg_cores) > j; j++, i++) | |
1901 | drbg_fill_array(&drbg_algs[i], &drbg_cores[j], 1); | |
1902 | for (j = 0; ARRAY_SIZE(drbg_cores) > j; j++, i++) | |
1903 | drbg_fill_array(&drbg_algs[i], &drbg_cores[j], 0); | |
1904 | return crypto_register_rngs(drbg_algs, (ARRAY_SIZE(drbg_cores) * 2)); | |
1905 | } | |
1906 | ||
1907 | static void __exit drbg_exit(void) | |
1908 | { | |
1909 | crypto_unregister_rngs(drbg_algs, (ARRAY_SIZE(drbg_cores) * 2)); | |
1910 | } | |
1911 | ||
1912 | module_init(drbg_init); | |
1913 | module_exit(drbg_exit); | |
1914 | #ifndef CRYPTO_DRBG_HASH_STRING | |
1915 | #define CRYPTO_DRBG_HASH_STRING "" | |
1916 | #endif | |
1917 | #ifndef CRYPTO_DRBG_HMAC_STRING | |
1918 | #define CRYPTO_DRBG_HMAC_STRING "" | |
1919 | #endif | |
1920 | #ifndef CRYPTO_DRBG_CTR_STRING | |
1921 | #define CRYPTO_DRBG_CTR_STRING "" | |
1922 | #endif | |
1923 | MODULE_LICENSE("GPL"); | |
1924 | MODULE_AUTHOR("Stephan Mueller <smueller@chronox.de>"); | |
1925 | MODULE_DESCRIPTION("NIST SP800-90A Deterministic Random Bit Generator (DRBG) " | |
1926 | "using following cores: " | |
1927 | CRYPTO_DRBG_HASH_STRING | |
1928 | CRYPTO_DRBG_HMAC_STRING | |
1929 | CRYPTO_DRBG_CTR_STRING); |