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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 | #include <linux/kernel.h> | |
102 | ||
103 | /*************************************************************** | |
104 | * Backend cipher definitions available to DRBG | |
105 | ***************************************************************/ | |
106 | ||
107 | /* | |
108 | * The order of the DRBG definitions here matter: every DRBG is registered | |
109 | * as stdrng. Each DRBG receives an increasing cra_priority values the later | |
110 | * they are defined in this array (see drbg_fill_array). | |
111 | * | |
112 | * HMAC DRBGs are favored over Hash DRBGs over CTR DRBGs, and | |
113 | * the SHA256 / AES 256 over other ciphers. Thus, the favored | |
114 | * DRBGs are the latest entries in this array. | |
115 | */ | |
116 | static const struct drbg_core drbg_cores[] = { | |
117 | #ifdef CONFIG_CRYPTO_DRBG_CTR | |
118 | { | |
119 | .flags = DRBG_CTR | DRBG_STRENGTH128, | |
120 | .statelen = 32, /* 256 bits as defined in 10.2.1 */ | |
121 | .blocklen_bytes = 16, | |
122 | .cra_name = "ctr_aes128", | |
123 | .backend_cra_name = "aes", | |
124 | }, { | |
125 | .flags = DRBG_CTR | DRBG_STRENGTH192, | |
126 | .statelen = 40, /* 320 bits as defined in 10.2.1 */ | |
127 | .blocklen_bytes = 16, | |
128 | .cra_name = "ctr_aes192", | |
129 | .backend_cra_name = "aes", | |
130 | }, { | |
131 | .flags = DRBG_CTR | DRBG_STRENGTH256, | |
132 | .statelen = 48, /* 384 bits as defined in 10.2.1 */ | |
133 | .blocklen_bytes = 16, | |
134 | .cra_name = "ctr_aes256", | |
135 | .backend_cra_name = "aes", | |
136 | }, | |
137 | #endif /* CONFIG_CRYPTO_DRBG_CTR */ | |
138 | #ifdef CONFIG_CRYPTO_DRBG_HASH | |
139 | { | |
140 | .flags = DRBG_HASH | DRBG_STRENGTH128, | |
141 | .statelen = 55, /* 440 bits */ | |
142 | .blocklen_bytes = 20, | |
143 | .cra_name = "sha1", | |
144 | .backend_cra_name = "sha1", | |
145 | }, { | |
146 | .flags = DRBG_HASH | DRBG_STRENGTH256, | |
147 | .statelen = 111, /* 888 bits */ | |
148 | .blocklen_bytes = 48, | |
149 | .cra_name = "sha384", | |
150 | .backend_cra_name = "sha384", | |
151 | }, { | |
152 | .flags = DRBG_HASH | DRBG_STRENGTH256, | |
153 | .statelen = 111, /* 888 bits */ | |
154 | .blocklen_bytes = 64, | |
155 | .cra_name = "sha512", | |
156 | .backend_cra_name = "sha512", | |
157 | }, { | |
158 | .flags = DRBG_HASH | DRBG_STRENGTH256, | |
159 | .statelen = 55, /* 440 bits */ | |
160 | .blocklen_bytes = 32, | |
161 | .cra_name = "sha256", | |
162 | .backend_cra_name = "sha256", | |
163 | }, | |
164 | #endif /* CONFIG_CRYPTO_DRBG_HASH */ | |
165 | #ifdef CONFIG_CRYPTO_DRBG_HMAC | |
166 | { | |
167 | .flags = DRBG_HMAC | DRBG_STRENGTH128, | |
168 | .statelen = 20, /* block length of cipher */ | |
169 | .blocklen_bytes = 20, | |
170 | .cra_name = "hmac_sha1", | |
171 | .backend_cra_name = "hmac(sha1)", | |
172 | }, { | |
173 | .flags = DRBG_HMAC | DRBG_STRENGTH256, | |
174 | .statelen = 48, /* block length of cipher */ | |
175 | .blocklen_bytes = 48, | |
176 | .cra_name = "hmac_sha384", | |
177 | .backend_cra_name = "hmac(sha384)", | |
178 | }, { | |
179 | .flags = DRBG_HMAC | DRBG_STRENGTH256, | |
180 | .statelen = 64, /* block length of cipher */ | |
181 | .blocklen_bytes = 64, | |
182 | .cra_name = "hmac_sha512", | |
183 | .backend_cra_name = "hmac(sha512)", | |
184 | }, { | |
185 | .flags = DRBG_HMAC | DRBG_STRENGTH256, | |
186 | .statelen = 32, /* block length of cipher */ | |
187 | .blocklen_bytes = 32, | |
188 | .cra_name = "hmac_sha256", | |
189 | .backend_cra_name = "hmac(sha256)", | |
190 | }, | |
191 | #endif /* CONFIG_CRYPTO_DRBG_HMAC */ | |
192 | }; | |
193 | ||
194 | static int drbg_uninstantiate(struct drbg_state *drbg); | |
195 | ||
196 | /****************************************************************** | |
197 | * Generic helper functions | |
198 | ******************************************************************/ | |
199 | ||
200 | /* | |
201 | * Return strength of DRBG according to SP800-90A section 8.4 | |
202 | * | |
203 | * @flags DRBG flags reference | |
204 | * | |
205 | * Return: normalized strength in *bytes* value or 32 as default | |
206 | * to counter programming errors | |
207 | */ | |
208 | static inline unsigned short drbg_sec_strength(drbg_flag_t flags) | |
209 | { | |
210 | switch (flags & DRBG_STRENGTH_MASK) { | |
211 | case DRBG_STRENGTH128: | |
212 | return 16; | |
213 | case DRBG_STRENGTH192: | |
214 | return 24; | |
215 | case DRBG_STRENGTH256: | |
216 | return 32; | |
217 | default: | |
218 | return 32; | |
219 | } | |
220 | } | |
221 | ||
222 | /* | |
223 | * FIPS 140-2 continuous self test | |
224 | * The test is performed on the result of one round of the output | |
225 | * function. Thus, the function implicitly knows the size of the | |
226 | * buffer. | |
227 | * | |
228 | * @drbg DRBG handle | |
229 | * @buf output buffer of random data to be checked | |
230 | * | |
231 | * return: | |
232 | * true on success | |
233 | * false on error | |
234 | */ | |
235 | static bool drbg_fips_continuous_test(struct drbg_state *drbg, | |
236 | const unsigned char *buf) | |
237 | { | |
238 | #ifdef CONFIG_CRYPTO_FIPS | |
239 | int ret = 0; | |
240 | /* skip test if we test the overall system */ | |
241 | if (list_empty(&drbg->test_data.list)) | |
242 | return true; | |
243 | /* only perform test in FIPS mode */ | |
244 | if (0 == fips_enabled) | |
245 | return true; | |
246 | if (!drbg->fips_primed) { | |
247 | /* Priming of FIPS test */ | |
248 | memcpy(drbg->prev, buf, drbg_blocklen(drbg)); | |
249 | drbg->fips_primed = true; | |
250 | /* return false due to priming, i.e. another round is needed */ | |
251 | return false; | |
252 | } | |
253 | ret = memcmp(drbg->prev, buf, drbg_blocklen(drbg)); | |
254 | if (!ret) | |
255 | panic("DRBG continuous self test failed\n"); | |
256 | memcpy(drbg->prev, buf, drbg_blocklen(drbg)); | |
257 | /* the test shall pass when the two compared values are not equal */ | |
258 | return ret != 0; | |
259 | #else | |
260 | return true; | |
261 | #endif /* CONFIG_CRYPTO_FIPS */ | |
262 | } | |
263 | ||
264 | /* | |
265 | * Convert an integer into a byte representation of this integer. | |
266 | * The byte representation is big-endian | |
267 | * | |
268 | * @val value to be converted | |
269 | * @buf buffer holding the converted integer -- caller must ensure that | |
270 | * buffer size is at least 32 bit | |
271 | */ | |
272 | #if (defined(CONFIG_CRYPTO_DRBG_HASH) || defined(CONFIG_CRYPTO_DRBG_CTR)) | |
273 | static inline void drbg_cpu_to_be32(__u32 val, unsigned char *buf) | |
274 | { | |
275 | struct s { | |
276 | __be32 conv; | |
277 | }; | |
278 | struct s *conversion = (struct s *) buf; | |
279 | ||
280 | conversion->conv = cpu_to_be32(val); | |
281 | } | |
282 | #endif /* defined(CONFIG_CRYPTO_DRBG_HASH) || defined(CONFIG_CRYPTO_DRBG_CTR) */ | |
283 | ||
284 | /****************************************************************** | |
285 | * CTR DRBG callback functions | |
286 | ******************************************************************/ | |
287 | ||
288 | #ifdef CONFIG_CRYPTO_DRBG_CTR | |
289 | #define CRYPTO_DRBG_CTR_STRING "CTR " | |
290 | MODULE_ALIAS_CRYPTO("drbg_pr_ctr_aes256"); | |
291 | MODULE_ALIAS_CRYPTO("drbg_nopr_ctr_aes256"); | |
292 | MODULE_ALIAS_CRYPTO("drbg_pr_ctr_aes192"); | |
293 | MODULE_ALIAS_CRYPTO("drbg_nopr_ctr_aes192"); | |
294 | MODULE_ALIAS_CRYPTO("drbg_pr_ctr_aes128"); | |
295 | MODULE_ALIAS_CRYPTO("drbg_nopr_ctr_aes128"); | |
296 | ||
297 | static int drbg_kcapi_sym(struct drbg_state *drbg, const unsigned char *key, | |
298 | unsigned char *outval, const struct drbg_string *in); | |
299 | static int drbg_init_sym_kernel(struct drbg_state *drbg); | |
300 | static int drbg_fini_sym_kernel(struct drbg_state *drbg); | |
301 | ||
302 | /* BCC function for CTR DRBG as defined in 10.4.3 */ | |
303 | static int drbg_ctr_bcc(struct drbg_state *drbg, | |
304 | unsigned char *out, const unsigned char *key, | |
305 | struct list_head *in) | |
306 | { | |
307 | int ret = 0; | |
308 | struct drbg_string *curr = NULL; | |
309 | struct drbg_string data; | |
310 | short cnt = 0; | |
311 | ||
312 | drbg_string_fill(&data, out, drbg_blocklen(drbg)); | |
313 | ||
314 | /* 10.4.3 step 2 / 4 */ | |
315 | list_for_each_entry(curr, in, list) { | |
316 | const unsigned char *pos = curr->buf; | |
317 | size_t len = curr->len; | |
318 | /* 10.4.3 step 4.1 */ | |
319 | while (len) { | |
320 | /* 10.4.3 step 4.2 */ | |
321 | if (drbg_blocklen(drbg) == cnt) { | |
322 | cnt = 0; | |
323 | ret = drbg_kcapi_sym(drbg, key, out, &data); | |
324 | if (ret) | |
325 | return ret; | |
326 | } | |
327 | out[cnt] ^= *pos; | |
328 | pos++; | |
329 | cnt++; | |
330 | len--; | |
331 | } | |
332 | } | |
333 | /* 10.4.3 step 4.2 for last block */ | |
334 | if (cnt) | |
335 | ret = drbg_kcapi_sym(drbg, key, out, &data); | |
336 | ||
337 | return ret; | |
338 | } | |
339 | ||
340 | /* | |
341 | * scratchpad usage: drbg_ctr_update is interlinked with drbg_ctr_df | |
342 | * (and drbg_ctr_bcc, but this function does not need any temporary buffers), | |
343 | * the scratchpad is used as follows: | |
344 | * drbg_ctr_update: | |
345 | * temp | |
346 | * start: drbg->scratchpad | |
347 | * length: drbg_statelen(drbg) + drbg_blocklen(drbg) | |
348 | * note: the cipher writing into this variable works | |
349 | * blocklen-wise. Now, when the statelen is not a multiple | |
350 | * of blocklen, the generateion loop below "spills over" | |
351 | * by at most blocklen. Thus, we need to give sufficient | |
352 | * memory. | |
353 | * df_data | |
354 | * start: drbg->scratchpad + | |
355 | * drbg_statelen(drbg) + drbg_blocklen(drbg) | |
356 | * length: drbg_statelen(drbg) | |
357 | * | |
358 | * drbg_ctr_df: | |
359 | * pad | |
360 | * start: df_data + drbg_statelen(drbg) | |
361 | * length: drbg_blocklen(drbg) | |
362 | * iv | |
363 | * start: pad + drbg_blocklen(drbg) | |
364 | * length: drbg_blocklen(drbg) | |
365 | * temp | |
366 | * start: iv + drbg_blocklen(drbg) | |
367 | * length: drbg_satelen(drbg) + drbg_blocklen(drbg) | |
368 | * note: temp is the buffer that the BCC function operates | |
369 | * on. BCC operates blockwise. drbg_statelen(drbg) | |
370 | * is sufficient when the DRBG state length is a multiple | |
371 | * of the block size. For AES192 (and maybe other ciphers) | |
372 | * this is not correct and the length for temp is | |
373 | * insufficient (yes, that also means for such ciphers, | |
374 | * the final output of all BCC rounds are truncated). | |
375 | * Therefore, add drbg_blocklen(drbg) to cover all | |
376 | * possibilities. | |
377 | */ | |
378 | ||
379 | /* Derivation Function for CTR DRBG as defined in 10.4.2 */ | |
380 | static int drbg_ctr_df(struct drbg_state *drbg, | |
381 | unsigned char *df_data, size_t bytes_to_return, | |
382 | struct list_head *seedlist) | |
383 | { | |
384 | int ret = -EFAULT; | |
385 | unsigned char L_N[8]; | |
386 | /* S3 is input */ | |
387 | struct drbg_string S1, S2, S4, cipherin; | |
388 | LIST_HEAD(bcc_list); | |
389 | unsigned char *pad = df_data + drbg_statelen(drbg); | |
390 | unsigned char *iv = pad + drbg_blocklen(drbg); | |
391 | unsigned char *temp = iv + drbg_blocklen(drbg); | |
392 | size_t padlen = 0; | |
393 | unsigned int templen = 0; | |
394 | /* 10.4.2 step 7 */ | |
395 | unsigned int i = 0; | |
396 | /* 10.4.2 step 8 */ | |
397 | const unsigned char *K = (unsigned char *) | |
398 | "\x00\x01\x02\x03\x04\x05\x06\x07" | |
399 | "\x08\x09\x0a\x0b\x0c\x0d\x0e\x0f" | |
400 | "\x10\x11\x12\x13\x14\x15\x16\x17" | |
401 | "\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f"; | |
402 | unsigned char *X; | |
403 | size_t generated_len = 0; | |
404 | size_t inputlen = 0; | |
405 | struct drbg_string *seed = NULL; | |
406 | ||
407 | memset(pad, 0, drbg_blocklen(drbg)); | |
408 | memset(iv, 0, drbg_blocklen(drbg)); | |
409 | ||
410 | /* 10.4.2 step 1 is implicit as we work byte-wise */ | |
411 | ||
412 | /* 10.4.2 step 2 */ | |
413 | if ((512/8) < bytes_to_return) | |
414 | return -EINVAL; | |
415 | ||
416 | /* 10.4.2 step 2 -- calculate the entire length of all input data */ | |
417 | list_for_each_entry(seed, seedlist, list) | |
418 | inputlen += seed->len; | |
419 | drbg_cpu_to_be32(inputlen, &L_N[0]); | |
420 | ||
421 | /* 10.4.2 step 3 */ | |
422 | drbg_cpu_to_be32(bytes_to_return, &L_N[4]); | |
423 | ||
424 | /* 10.4.2 step 5: length is L_N, input_string, one byte, padding */ | |
425 | padlen = (inputlen + sizeof(L_N) + 1) % (drbg_blocklen(drbg)); | |
426 | /* wrap the padlen appropriately */ | |
427 | if (padlen) | |
428 | padlen = drbg_blocklen(drbg) - padlen; | |
429 | /* | |
430 | * pad / padlen contains the 0x80 byte and the following zero bytes. | |
431 | * As the calculated padlen value only covers the number of zero | |
432 | * bytes, this value has to be incremented by one for the 0x80 byte. | |
433 | */ | |
434 | padlen++; | |
435 | pad[0] = 0x80; | |
436 | ||
437 | /* 10.4.2 step 4 -- first fill the linked list and then order it */ | |
438 | drbg_string_fill(&S1, iv, drbg_blocklen(drbg)); | |
439 | list_add_tail(&S1.list, &bcc_list); | |
440 | drbg_string_fill(&S2, L_N, sizeof(L_N)); | |
441 | list_add_tail(&S2.list, &bcc_list); | |
442 | list_splice_tail(seedlist, &bcc_list); | |
443 | drbg_string_fill(&S4, pad, padlen); | |
444 | list_add_tail(&S4.list, &bcc_list); | |
445 | ||
446 | /* 10.4.2 step 9 */ | |
447 | while (templen < (drbg_keylen(drbg) + (drbg_blocklen(drbg)))) { | |
448 | /* | |
449 | * 10.4.2 step 9.1 - the padding is implicit as the buffer | |
450 | * holds zeros after allocation -- even the increment of i | |
451 | * is irrelevant as the increment remains within length of i | |
452 | */ | |
453 | drbg_cpu_to_be32(i, iv); | |
454 | /* 10.4.2 step 9.2 -- BCC and concatenation with temp */ | |
455 | ret = drbg_ctr_bcc(drbg, temp + templen, K, &bcc_list); | |
456 | if (ret) | |
457 | goto out; | |
458 | /* 10.4.2 step 9.3 */ | |
459 | i++; | |
460 | templen += drbg_blocklen(drbg); | |
461 | } | |
462 | ||
463 | /* 10.4.2 step 11 */ | |
464 | X = temp + (drbg_keylen(drbg)); | |
465 | drbg_string_fill(&cipherin, X, drbg_blocklen(drbg)); | |
466 | ||
467 | /* 10.4.2 step 12: overwriting of outval is implemented in next step */ | |
468 | ||
469 | /* 10.4.2 step 13 */ | |
470 | while (generated_len < bytes_to_return) { | |
471 | short blocklen = 0; | |
472 | /* | |
473 | * 10.4.2 step 13.1: the truncation of the key length is | |
474 | * implicit as the key is only drbg_blocklen in size based on | |
475 | * the implementation of the cipher function callback | |
476 | */ | |
477 | ret = drbg_kcapi_sym(drbg, temp, X, &cipherin); | |
478 | if (ret) | |
479 | goto out; | |
480 | blocklen = (drbg_blocklen(drbg) < | |
481 | (bytes_to_return - generated_len)) ? | |
482 | drbg_blocklen(drbg) : | |
483 | (bytes_to_return - generated_len); | |
484 | /* 10.4.2 step 13.2 and 14 */ | |
485 | memcpy(df_data + generated_len, X, blocklen); | |
486 | generated_len += blocklen; | |
487 | } | |
488 | ||
489 | ret = 0; | |
490 | ||
491 | out: | |
492 | memset(iv, 0, drbg_blocklen(drbg)); | |
493 | memset(temp, 0, drbg_statelen(drbg) + drbg_blocklen(drbg)); | |
494 | memset(pad, 0, drbg_blocklen(drbg)); | |
495 | return ret; | |
496 | } | |
497 | ||
498 | /* | |
499 | * update function of CTR DRBG as defined in 10.2.1.2 | |
500 | * | |
501 | * The reseed variable has an enhanced meaning compared to the update | |
502 | * functions of the other DRBGs as follows: | |
503 | * 0 => initial seed from initialization | |
504 | * 1 => reseed via drbg_seed | |
505 | * 2 => first invocation from drbg_ctr_update when addtl is present. In | |
506 | * this case, the df_data scratchpad is not deleted so that it is | |
507 | * available for another calls to prevent calling the DF function | |
508 | * again. | |
509 | * 3 => second invocation from drbg_ctr_update. When the update function | |
510 | * was called with addtl, the df_data memory already contains the | |
511 | * DFed addtl information and we do not need to call DF again. | |
512 | */ | |
513 | static int drbg_ctr_update(struct drbg_state *drbg, struct list_head *seed, | |
514 | int reseed) | |
515 | { | |
516 | int ret = -EFAULT; | |
517 | /* 10.2.1.2 step 1 */ | |
518 | unsigned char *temp = drbg->scratchpad; | |
519 | unsigned char *df_data = drbg->scratchpad + drbg_statelen(drbg) + | |
520 | drbg_blocklen(drbg); | |
521 | unsigned char *temp_p, *df_data_p; /* pointer to iterate over buffers */ | |
522 | unsigned int len = 0; | |
523 | struct drbg_string cipherin; | |
524 | ||
525 | if (3 > reseed) | |
526 | memset(df_data, 0, drbg_statelen(drbg)); | |
527 | ||
528 | /* 10.2.1.3.2 step 2 and 10.2.1.4.2 step 2 */ | |
529 | if (seed) { | |
530 | ret = drbg_ctr_df(drbg, df_data, drbg_statelen(drbg), seed); | |
531 | if (ret) | |
532 | goto out; | |
533 | } | |
534 | ||
535 | drbg_string_fill(&cipherin, drbg->V, drbg_blocklen(drbg)); | |
536 | /* | |
537 | * 10.2.1.3.2 steps 2 and 3 are already covered as the allocation | |
538 | * zeroizes all memory during initialization | |
539 | */ | |
540 | while (len < (drbg_statelen(drbg))) { | |
541 | /* 10.2.1.2 step 2.1 */ | |
542 | crypto_inc(drbg->V, drbg_blocklen(drbg)); | |
543 | /* | |
544 | * 10.2.1.2 step 2.2 */ | |
545 | ret = drbg_kcapi_sym(drbg, drbg->C, temp + len, &cipherin); | |
546 | if (ret) | |
547 | goto out; | |
548 | /* 10.2.1.2 step 2.3 and 3 */ | |
549 | len += drbg_blocklen(drbg); | |
550 | } | |
551 | ||
552 | /* 10.2.1.2 step 4 */ | |
553 | temp_p = temp; | |
554 | df_data_p = df_data; | |
555 | for (len = 0; len < drbg_statelen(drbg); len++) { | |
556 | *temp_p ^= *df_data_p; | |
557 | df_data_p++; temp_p++; | |
558 | } | |
559 | ||
560 | /* 10.2.1.2 step 5 */ | |
561 | memcpy(drbg->C, temp, drbg_keylen(drbg)); | |
562 | /* 10.2.1.2 step 6 */ | |
563 | memcpy(drbg->V, temp + drbg_keylen(drbg), drbg_blocklen(drbg)); | |
564 | ret = 0; | |
565 | ||
566 | out: | |
567 | memset(temp, 0, drbg_statelen(drbg) + drbg_blocklen(drbg)); | |
568 | if (2 != reseed) | |
569 | memset(df_data, 0, drbg_statelen(drbg)); | |
570 | return ret; | |
571 | } | |
572 | ||
573 | /* | |
574 | * scratchpad use: drbg_ctr_update is called independently from | |
575 | * drbg_ctr_extract_bytes. Therefore, the scratchpad is reused | |
576 | */ | |
577 | /* Generate function of CTR DRBG as defined in 10.2.1.5.2 */ | |
578 | static int drbg_ctr_generate(struct drbg_state *drbg, | |
579 | unsigned char *buf, unsigned int buflen, | |
580 | struct list_head *addtl) | |
581 | { | |
582 | int len = 0; | |
583 | int ret = 0; | |
584 | struct drbg_string data; | |
585 | ||
586 | /* 10.2.1.5.2 step 2 */ | |
587 | if (addtl && !list_empty(addtl)) { | |
588 | ret = drbg_ctr_update(drbg, addtl, 2); | |
589 | if (ret) | |
590 | return 0; | |
591 | } | |
592 | ||
593 | /* 10.2.1.5.2 step 4.1 */ | |
594 | crypto_inc(drbg->V, drbg_blocklen(drbg)); | |
595 | drbg_string_fill(&data, drbg->V, drbg_blocklen(drbg)); | |
596 | while (len < buflen) { | |
597 | int outlen = 0; | |
598 | /* 10.2.1.5.2 step 4.2 */ | |
599 | ret = drbg_kcapi_sym(drbg, drbg->C, drbg->scratchpad, &data); | |
600 | if (ret) { | |
601 | len = ret; | |
602 | goto out; | |
603 | } | |
604 | outlen = (drbg_blocklen(drbg) < (buflen - len)) ? | |
605 | drbg_blocklen(drbg) : (buflen - len); | |
606 | if (!drbg_fips_continuous_test(drbg, drbg->scratchpad)) { | |
607 | /* 10.2.1.5.2 step 6 */ | |
608 | crypto_inc(drbg->V, drbg_blocklen(drbg)); | |
609 | continue; | |
610 | } | |
611 | /* 10.2.1.5.2 step 4.3 */ | |
612 | memcpy(buf + len, drbg->scratchpad, outlen); | |
613 | len += outlen; | |
614 | /* 10.2.1.5.2 step 6 */ | |
615 | if (len < buflen) | |
616 | crypto_inc(drbg->V, drbg_blocklen(drbg)); | |
617 | } | |
618 | ||
619 | /* 10.2.1.5.2 step 6 */ | |
620 | ret = drbg_ctr_update(drbg, NULL, 3); | |
621 | if (ret) | |
622 | len = ret; | |
623 | ||
624 | out: | |
625 | memset(drbg->scratchpad, 0, drbg_blocklen(drbg)); | |
626 | return len; | |
627 | } | |
628 | ||
629 | static struct drbg_state_ops drbg_ctr_ops = { | |
630 | .update = drbg_ctr_update, | |
631 | .generate = drbg_ctr_generate, | |
632 | .crypto_init = drbg_init_sym_kernel, | |
633 | .crypto_fini = drbg_fini_sym_kernel, | |
634 | }; | |
635 | #endif /* CONFIG_CRYPTO_DRBG_CTR */ | |
636 | ||
637 | /****************************************************************** | |
638 | * HMAC DRBG callback functions | |
639 | ******************************************************************/ | |
640 | ||
641 | #if defined(CONFIG_CRYPTO_DRBG_HASH) || defined(CONFIG_CRYPTO_DRBG_HMAC) | |
642 | static int drbg_kcapi_hash(struct drbg_state *drbg, const unsigned char *key, | |
643 | unsigned char *outval, const struct list_head *in); | |
644 | static int drbg_init_hash_kernel(struct drbg_state *drbg); | |
645 | static int drbg_fini_hash_kernel(struct drbg_state *drbg); | |
646 | #endif /* (CONFIG_CRYPTO_DRBG_HASH || CONFIG_CRYPTO_DRBG_HMAC) */ | |
647 | ||
648 | #ifdef CONFIG_CRYPTO_DRBG_HMAC | |
649 | #define CRYPTO_DRBG_HMAC_STRING "HMAC " | |
650 | MODULE_ALIAS_CRYPTO("drbg_pr_hmac_sha512"); | |
651 | MODULE_ALIAS_CRYPTO("drbg_nopr_hmac_sha512"); | |
652 | MODULE_ALIAS_CRYPTO("drbg_pr_hmac_sha384"); | |
653 | MODULE_ALIAS_CRYPTO("drbg_nopr_hmac_sha384"); | |
654 | MODULE_ALIAS_CRYPTO("drbg_pr_hmac_sha256"); | |
655 | MODULE_ALIAS_CRYPTO("drbg_nopr_hmac_sha256"); | |
656 | MODULE_ALIAS_CRYPTO("drbg_pr_hmac_sha1"); | |
657 | MODULE_ALIAS_CRYPTO("drbg_nopr_hmac_sha1"); | |
658 | ||
659 | /* update function of HMAC DRBG as defined in 10.1.2.2 */ | |
660 | static int drbg_hmac_update(struct drbg_state *drbg, struct list_head *seed, | |
661 | int reseed) | |
662 | { | |
663 | int ret = -EFAULT; | |
664 | int i = 0; | |
665 | struct drbg_string seed1, seed2, vdata; | |
666 | LIST_HEAD(seedlist); | |
667 | LIST_HEAD(vdatalist); | |
668 | ||
669 | if (!reseed) | |
670 | /* 10.1.2.3 step 2 -- memset(0) of C is implicit with kzalloc */ | |
671 | memset(drbg->V, 1, drbg_statelen(drbg)); | |
672 | ||
673 | drbg_string_fill(&seed1, drbg->V, drbg_statelen(drbg)); | |
674 | list_add_tail(&seed1.list, &seedlist); | |
675 | /* buffer of seed2 will be filled in for loop below with one byte */ | |
676 | drbg_string_fill(&seed2, NULL, 1); | |
677 | list_add_tail(&seed2.list, &seedlist); | |
678 | /* input data of seed is allowed to be NULL at this point */ | |
679 | if (seed) | |
680 | list_splice_tail(seed, &seedlist); | |
681 | ||
682 | drbg_string_fill(&vdata, drbg->V, drbg_statelen(drbg)); | |
683 | list_add_tail(&vdata.list, &vdatalist); | |
684 | for (i = 2; 0 < i; i--) { | |
685 | /* first round uses 0x0, second 0x1 */ | |
686 | unsigned char prefix = DRBG_PREFIX0; | |
687 | if (1 == i) | |
688 | prefix = DRBG_PREFIX1; | |
689 | /* 10.1.2.2 step 1 and 4 -- concatenation and HMAC for key */ | |
690 | seed2.buf = &prefix; | |
691 | ret = drbg_kcapi_hash(drbg, drbg->C, drbg->C, &seedlist); | |
692 | if (ret) | |
693 | return ret; | |
694 | ||
695 | /* 10.1.2.2 step 2 and 5 -- HMAC for V */ | |
696 | ret = drbg_kcapi_hash(drbg, drbg->C, drbg->V, &vdatalist); | |
697 | if (ret) | |
698 | return ret; | |
699 | ||
700 | /* 10.1.2.2 step 3 */ | |
701 | if (!seed) | |
702 | return ret; | |
703 | } | |
704 | ||
705 | return 0; | |
706 | } | |
707 | ||
708 | /* generate function of HMAC DRBG as defined in 10.1.2.5 */ | |
709 | static int drbg_hmac_generate(struct drbg_state *drbg, | |
710 | unsigned char *buf, | |
711 | unsigned int buflen, | |
712 | struct list_head *addtl) | |
713 | { | |
714 | int len = 0; | |
715 | int ret = 0; | |
716 | struct drbg_string data; | |
717 | LIST_HEAD(datalist); | |
718 | ||
719 | /* 10.1.2.5 step 2 */ | |
720 | if (addtl && !list_empty(addtl)) { | |
721 | ret = drbg_hmac_update(drbg, addtl, 1); | |
722 | if (ret) | |
723 | return ret; | |
724 | } | |
725 | ||
726 | drbg_string_fill(&data, drbg->V, drbg_statelen(drbg)); | |
727 | list_add_tail(&data.list, &datalist); | |
728 | while (len < buflen) { | |
729 | unsigned int outlen = 0; | |
730 | /* 10.1.2.5 step 4.1 */ | |
731 | ret = drbg_kcapi_hash(drbg, drbg->C, drbg->V, &datalist); | |
732 | if (ret) | |
733 | return ret; | |
734 | outlen = (drbg_blocklen(drbg) < (buflen - len)) ? | |
735 | drbg_blocklen(drbg) : (buflen - len); | |
736 | if (!drbg_fips_continuous_test(drbg, drbg->V)) | |
737 | continue; | |
738 | ||
739 | /* 10.1.2.5 step 4.2 */ | |
740 | memcpy(buf + len, drbg->V, outlen); | |
741 | len += outlen; | |
742 | } | |
743 | ||
744 | /* 10.1.2.5 step 6 */ | |
745 | if (addtl && !list_empty(addtl)) | |
746 | ret = drbg_hmac_update(drbg, addtl, 1); | |
747 | else | |
748 | ret = drbg_hmac_update(drbg, NULL, 1); | |
749 | if (ret) | |
750 | return ret; | |
751 | ||
752 | return len; | |
753 | } | |
754 | ||
755 | static struct drbg_state_ops drbg_hmac_ops = { | |
756 | .update = drbg_hmac_update, | |
757 | .generate = drbg_hmac_generate, | |
758 | .crypto_init = drbg_init_hash_kernel, | |
759 | .crypto_fini = drbg_fini_hash_kernel, | |
760 | }; | |
761 | #endif /* CONFIG_CRYPTO_DRBG_HMAC */ | |
762 | ||
763 | /****************************************************************** | |
764 | * Hash DRBG callback functions | |
765 | ******************************************************************/ | |
766 | ||
767 | #ifdef CONFIG_CRYPTO_DRBG_HASH | |
768 | #define CRYPTO_DRBG_HASH_STRING "HASH " | |
769 | MODULE_ALIAS_CRYPTO("drbg_pr_sha512"); | |
770 | MODULE_ALIAS_CRYPTO("drbg_nopr_sha512"); | |
771 | MODULE_ALIAS_CRYPTO("drbg_pr_sha384"); | |
772 | MODULE_ALIAS_CRYPTO("drbg_nopr_sha384"); | |
773 | MODULE_ALIAS_CRYPTO("drbg_pr_sha256"); | |
774 | MODULE_ALIAS_CRYPTO("drbg_nopr_sha256"); | |
775 | MODULE_ALIAS_CRYPTO("drbg_pr_sha1"); | |
776 | MODULE_ALIAS_CRYPTO("drbg_nopr_sha1"); | |
777 | ||
778 | /* | |
779 | * Increment buffer | |
780 | * | |
781 | * @dst buffer to increment | |
782 | * @add value to add | |
783 | */ | |
784 | static inline void drbg_add_buf(unsigned char *dst, size_t dstlen, | |
785 | const unsigned char *add, size_t addlen) | |
786 | { | |
787 | /* implied: dstlen > addlen */ | |
788 | unsigned char *dstptr; | |
789 | const unsigned char *addptr; | |
790 | unsigned int remainder = 0; | |
791 | size_t len = addlen; | |
792 | ||
793 | dstptr = dst + (dstlen-1); | |
794 | addptr = add + (addlen-1); | |
795 | while (len) { | |
796 | remainder += *dstptr + *addptr; | |
797 | *dstptr = remainder & 0xff; | |
798 | remainder >>= 8; | |
799 | len--; dstptr--; addptr--; | |
800 | } | |
801 | len = dstlen - addlen; | |
802 | while (len && remainder > 0) { | |
803 | remainder = *dstptr + 1; | |
804 | *dstptr = remainder & 0xff; | |
805 | remainder >>= 8; | |
806 | len--; dstptr--; | |
807 | } | |
808 | } | |
809 | ||
810 | /* | |
811 | * scratchpad usage: as drbg_hash_update and drbg_hash_df are used | |
812 | * interlinked, the scratchpad is used as follows: | |
813 | * drbg_hash_update | |
814 | * start: drbg->scratchpad | |
815 | * length: drbg_statelen(drbg) | |
816 | * drbg_hash_df: | |
817 | * start: drbg->scratchpad + drbg_statelen(drbg) | |
818 | * length: drbg_blocklen(drbg) | |
819 | * | |
820 | * drbg_hash_process_addtl uses the scratchpad, but fully completes | |
821 | * before either of the functions mentioned before are invoked. Therefore, | |
822 | * drbg_hash_process_addtl does not need to be specifically considered. | |
823 | */ | |
824 | ||
825 | /* Derivation Function for Hash DRBG as defined in 10.4.1 */ | |
826 | static int drbg_hash_df(struct drbg_state *drbg, | |
827 | unsigned char *outval, size_t outlen, | |
828 | struct list_head *entropylist) | |
829 | { | |
830 | int ret = 0; | |
831 | size_t len = 0; | |
832 | unsigned char input[5]; | |
833 | unsigned char *tmp = drbg->scratchpad + drbg_statelen(drbg); | |
834 | struct drbg_string data; | |
835 | ||
836 | /* 10.4.1 step 3 */ | |
837 | input[0] = 1; | |
838 | drbg_cpu_to_be32((outlen * 8), &input[1]); | |
839 | ||
840 | /* 10.4.1 step 4.1 -- concatenation of data for input into hash */ | |
841 | drbg_string_fill(&data, input, 5); | |
842 | list_add(&data.list, entropylist); | |
843 | ||
844 | /* 10.4.1 step 4 */ | |
845 | while (len < outlen) { | |
846 | short blocklen = 0; | |
847 | /* 10.4.1 step 4.1 */ | |
848 | ret = drbg_kcapi_hash(drbg, NULL, tmp, entropylist); | |
849 | if (ret) | |
850 | goto out; | |
851 | /* 10.4.1 step 4.2 */ | |
852 | input[0]++; | |
853 | blocklen = (drbg_blocklen(drbg) < (outlen - len)) ? | |
854 | drbg_blocklen(drbg) : (outlen - len); | |
855 | memcpy(outval + len, tmp, blocklen); | |
856 | len += blocklen; | |
857 | } | |
858 | ||
859 | out: | |
860 | memset(tmp, 0, drbg_blocklen(drbg)); | |
861 | return ret; | |
862 | } | |
863 | ||
864 | /* update function for Hash DRBG as defined in 10.1.1.2 / 10.1.1.3 */ | |
865 | static int drbg_hash_update(struct drbg_state *drbg, struct list_head *seed, | |
866 | int reseed) | |
867 | { | |
868 | int ret = 0; | |
869 | struct drbg_string data1, data2; | |
870 | LIST_HEAD(datalist); | |
871 | LIST_HEAD(datalist2); | |
872 | unsigned char *V = drbg->scratchpad; | |
873 | unsigned char prefix = DRBG_PREFIX1; | |
874 | ||
875 | if (!seed) | |
876 | return -EINVAL; | |
877 | ||
878 | if (reseed) { | |
879 | /* 10.1.1.3 step 1 */ | |
880 | memcpy(V, drbg->V, drbg_statelen(drbg)); | |
881 | drbg_string_fill(&data1, &prefix, 1); | |
882 | list_add_tail(&data1.list, &datalist); | |
883 | drbg_string_fill(&data2, V, drbg_statelen(drbg)); | |
884 | list_add_tail(&data2.list, &datalist); | |
885 | } | |
886 | list_splice_tail(seed, &datalist); | |
887 | ||
888 | /* 10.1.1.2 / 10.1.1.3 step 2 and 3 */ | |
889 | ret = drbg_hash_df(drbg, drbg->V, drbg_statelen(drbg), &datalist); | |
890 | if (ret) | |
891 | goto out; | |
892 | ||
893 | /* 10.1.1.2 / 10.1.1.3 step 4 */ | |
894 | prefix = DRBG_PREFIX0; | |
895 | drbg_string_fill(&data1, &prefix, 1); | |
896 | list_add_tail(&data1.list, &datalist2); | |
897 | drbg_string_fill(&data2, drbg->V, drbg_statelen(drbg)); | |
898 | list_add_tail(&data2.list, &datalist2); | |
899 | /* 10.1.1.2 / 10.1.1.3 step 4 */ | |
900 | ret = drbg_hash_df(drbg, drbg->C, drbg_statelen(drbg), &datalist2); | |
901 | ||
902 | out: | |
903 | memset(drbg->scratchpad, 0, drbg_statelen(drbg)); | |
904 | return ret; | |
905 | } | |
906 | ||
907 | /* processing of additional information string for Hash DRBG */ | |
908 | static int drbg_hash_process_addtl(struct drbg_state *drbg, | |
909 | struct list_head *addtl) | |
910 | { | |
911 | int ret = 0; | |
912 | struct drbg_string data1, data2; | |
913 | LIST_HEAD(datalist); | |
914 | unsigned char prefix = DRBG_PREFIX2; | |
915 | ||
916 | /* 10.1.1.4 step 2 */ | |
917 | if (!addtl || list_empty(addtl)) | |
918 | return 0; | |
919 | ||
920 | /* 10.1.1.4 step 2a */ | |
921 | drbg_string_fill(&data1, &prefix, 1); | |
922 | drbg_string_fill(&data2, drbg->V, drbg_statelen(drbg)); | |
923 | list_add_tail(&data1.list, &datalist); | |
924 | list_add_tail(&data2.list, &datalist); | |
925 | list_splice_tail(addtl, &datalist); | |
926 | ret = drbg_kcapi_hash(drbg, NULL, drbg->scratchpad, &datalist); | |
927 | if (ret) | |
928 | goto out; | |
929 | ||
930 | /* 10.1.1.4 step 2b */ | |
931 | drbg_add_buf(drbg->V, drbg_statelen(drbg), | |
932 | drbg->scratchpad, drbg_blocklen(drbg)); | |
933 | ||
934 | out: | |
935 | memset(drbg->scratchpad, 0, drbg_blocklen(drbg)); | |
936 | return ret; | |
937 | } | |
938 | ||
939 | /* Hashgen defined in 10.1.1.4 */ | |
940 | static int drbg_hash_hashgen(struct drbg_state *drbg, | |
941 | unsigned char *buf, | |
942 | unsigned int buflen) | |
943 | { | |
944 | int len = 0; | |
945 | int ret = 0; | |
946 | unsigned char *src = drbg->scratchpad; | |
947 | unsigned char *dst = drbg->scratchpad + drbg_statelen(drbg); | |
948 | struct drbg_string data; | |
949 | LIST_HEAD(datalist); | |
950 | ||
951 | /* 10.1.1.4 step hashgen 2 */ | |
952 | memcpy(src, drbg->V, drbg_statelen(drbg)); | |
953 | ||
954 | drbg_string_fill(&data, src, drbg_statelen(drbg)); | |
955 | list_add_tail(&data.list, &datalist); | |
956 | while (len < buflen) { | |
957 | unsigned int outlen = 0; | |
958 | /* 10.1.1.4 step hashgen 4.1 */ | |
959 | ret = drbg_kcapi_hash(drbg, NULL, dst, &datalist); | |
960 | if (ret) { | |
961 | len = ret; | |
962 | goto out; | |
963 | } | |
964 | outlen = (drbg_blocklen(drbg) < (buflen - len)) ? | |
965 | drbg_blocklen(drbg) : (buflen - len); | |
966 | if (!drbg_fips_continuous_test(drbg, dst)) { | |
967 | crypto_inc(src, drbg_statelen(drbg)); | |
968 | continue; | |
969 | } | |
970 | /* 10.1.1.4 step hashgen 4.2 */ | |
971 | memcpy(buf + len, dst, outlen); | |
972 | len += outlen; | |
973 | /* 10.1.1.4 hashgen step 4.3 */ | |
974 | if (len < buflen) | |
975 | crypto_inc(src, drbg_statelen(drbg)); | |
976 | } | |
977 | ||
978 | out: | |
979 | memset(drbg->scratchpad, 0, | |
980 | (drbg_statelen(drbg) + drbg_blocklen(drbg))); | |
981 | return len; | |
982 | } | |
983 | ||
984 | /* generate function for Hash DRBG as defined in 10.1.1.4 */ | |
985 | static int drbg_hash_generate(struct drbg_state *drbg, | |
986 | unsigned char *buf, unsigned int buflen, | |
987 | struct list_head *addtl) | |
988 | { | |
989 | int len = 0; | |
990 | int ret = 0; | |
991 | union { | |
992 | unsigned char req[8]; | |
993 | __be64 req_int; | |
994 | } u; | |
995 | unsigned char prefix = DRBG_PREFIX3; | |
996 | struct drbg_string data1, data2; | |
997 | LIST_HEAD(datalist); | |
998 | ||
999 | /* 10.1.1.4 step 2 */ | |
1000 | ret = drbg_hash_process_addtl(drbg, addtl); | |
1001 | if (ret) | |
1002 | return ret; | |
1003 | /* 10.1.1.4 step 3 */ | |
1004 | len = drbg_hash_hashgen(drbg, buf, buflen); | |
1005 | ||
1006 | /* this is the value H as documented in 10.1.1.4 */ | |
1007 | /* 10.1.1.4 step 4 */ | |
1008 | drbg_string_fill(&data1, &prefix, 1); | |
1009 | list_add_tail(&data1.list, &datalist); | |
1010 | drbg_string_fill(&data2, drbg->V, drbg_statelen(drbg)); | |
1011 | list_add_tail(&data2.list, &datalist); | |
1012 | ret = drbg_kcapi_hash(drbg, NULL, drbg->scratchpad, &datalist); | |
1013 | if (ret) { | |
1014 | len = ret; | |
1015 | goto out; | |
1016 | } | |
1017 | ||
1018 | /* 10.1.1.4 step 5 */ | |
1019 | drbg_add_buf(drbg->V, drbg_statelen(drbg), | |
1020 | drbg->scratchpad, drbg_blocklen(drbg)); | |
1021 | drbg_add_buf(drbg->V, drbg_statelen(drbg), | |
1022 | drbg->C, drbg_statelen(drbg)); | |
1023 | u.req_int = cpu_to_be64(drbg->reseed_ctr); | |
1024 | drbg_add_buf(drbg->V, drbg_statelen(drbg), u.req, 8); | |
1025 | ||
1026 | out: | |
1027 | memset(drbg->scratchpad, 0, drbg_blocklen(drbg)); | |
1028 | return len; | |
1029 | } | |
1030 | ||
1031 | /* | |
1032 | * scratchpad usage: as update and generate are used isolated, both | |
1033 | * can use the scratchpad | |
1034 | */ | |
1035 | static struct drbg_state_ops drbg_hash_ops = { | |
1036 | .update = drbg_hash_update, | |
1037 | .generate = drbg_hash_generate, | |
1038 | .crypto_init = drbg_init_hash_kernel, | |
1039 | .crypto_fini = drbg_fini_hash_kernel, | |
1040 | }; | |
1041 | #endif /* CONFIG_CRYPTO_DRBG_HASH */ | |
1042 | ||
1043 | /****************************************************************** | |
1044 | * Functions common for DRBG implementations | |
1045 | ******************************************************************/ | |
1046 | ||
1047 | static inline int __drbg_seed(struct drbg_state *drbg, struct list_head *seed, | |
1048 | int reseed) | |
1049 | { | |
1050 | int ret = drbg->d_ops->update(drbg, seed, reseed); | |
1051 | ||
1052 | if (ret) | |
1053 | return ret; | |
1054 | ||
1055 | drbg->seeded = true; | |
1056 | /* 10.1.1.2 / 10.1.1.3 step 5 */ | |
1057 | drbg->reseed_ctr = 1; | |
1058 | ||
1059 | return ret; | |
1060 | } | |
1061 | ||
1062 | static void drbg_async_seed(struct work_struct *work) | |
1063 | { | |
1064 | struct drbg_string data; | |
1065 | LIST_HEAD(seedlist); | |
1066 | struct drbg_state *drbg = container_of(work, struct drbg_state, | |
1067 | seed_work); | |
1068 | unsigned int entropylen = drbg_sec_strength(drbg->core->flags); | |
1069 | unsigned char entropy[32]; | |
1070 | ||
1071 | BUG_ON(!entropylen); | |
1072 | BUG_ON(entropylen > sizeof(entropy)); | |
1073 | get_random_bytes(entropy, entropylen); | |
1074 | ||
1075 | drbg_string_fill(&data, entropy, entropylen); | |
1076 | list_add_tail(&data.list, &seedlist); | |
1077 | ||
1078 | mutex_lock(&drbg->drbg_mutex); | |
1079 | ||
1080 | /* If nonblocking pool is initialized, deactivate Jitter RNG */ | |
1081 | crypto_free_rng(drbg->jent); | |
1082 | drbg->jent = NULL; | |
1083 | ||
1084 | /* Set seeded to false so that if __drbg_seed fails the | |
1085 | * next generate call will trigger a reseed. | |
1086 | */ | |
1087 | drbg->seeded = false; | |
1088 | ||
1089 | __drbg_seed(drbg, &seedlist, true); | |
1090 | ||
1091 | mutex_unlock(&drbg->drbg_mutex); | |
1092 | ||
1093 | memzero_explicit(entropy, entropylen); | |
1094 | } | |
1095 | ||
1096 | /* | |
1097 | * Seeding or reseeding of the DRBG | |
1098 | * | |
1099 | * @drbg: DRBG state struct | |
1100 | * @pers: personalization / additional information buffer | |
1101 | * @reseed: 0 for initial seed process, 1 for reseeding | |
1102 | * | |
1103 | * return: | |
1104 | * 0 on success | |
1105 | * error value otherwise | |
1106 | */ | |
1107 | static int drbg_seed(struct drbg_state *drbg, struct drbg_string *pers, | |
1108 | bool reseed) | |
1109 | { | |
1110 | int ret; | |
1111 | unsigned char entropy[((32 + 16) * 2)]; | |
1112 | unsigned int entropylen = drbg_sec_strength(drbg->core->flags); | |
1113 | struct drbg_string data1; | |
1114 | LIST_HEAD(seedlist); | |
1115 | ||
1116 | /* 9.1 / 9.2 / 9.3.1 step 3 */ | |
1117 | if (pers && pers->len > (drbg_max_addtl(drbg))) { | |
1118 | pr_devel("DRBG: personalization string too long %zu\n", | |
1119 | pers->len); | |
1120 | return -EINVAL; | |
1121 | } | |
1122 | ||
1123 | if (list_empty(&drbg->test_data.list)) { | |
1124 | drbg_string_fill(&data1, drbg->test_data.buf, | |
1125 | drbg->test_data.len); | |
1126 | pr_devel("DRBG: using test entropy\n"); | |
1127 | } else { | |
1128 | /* | |
1129 | * Gather entropy equal to the security strength of the DRBG. | |
1130 | * With a derivation function, a nonce is required in addition | |
1131 | * to the entropy. A nonce must be at least 1/2 of the security | |
1132 | * strength of the DRBG in size. Thus, entropy + nonce is 3/2 | |
1133 | * of the strength. The consideration of a nonce is only | |
1134 | * applicable during initial seeding. | |
1135 | */ | |
1136 | BUG_ON(!entropylen); | |
1137 | if (!reseed) | |
1138 | entropylen = ((entropylen + 1) / 2) * 3; | |
1139 | BUG_ON((entropylen * 2) > sizeof(entropy)); | |
1140 | ||
1141 | /* Get seed from in-kernel /dev/urandom */ | |
1142 | get_random_bytes(entropy, entropylen); | |
1143 | ||
1144 | if (!drbg->jent) { | |
1145 | drbg_string_fill(&data1, entropy, entropylen); | |
1146 | pr_devel("DRBG: (re)seeding with %u bytes of entropy\n", | |
1147 | entropylen); | |
1148 | } else { | |
1149 | /* Get seed from Jitter RNG */ | |
1150 | ret = crypto_rng_get_bytes(drbg->jent, | |
1151 | entropy + entropylen, | |
1152 | entropylen); | |
1153 | if (ret) { | |
1154 | pr_devel("DRBG: jent failed with %d\n", ret); | |
1155 | return ret; | |
1156 | } | |
1157 | ||
1158 | drbg_string_fill(&data1, entropy, entropylen * 2); | |
1159 | pr_devel("DRBG: (re)seeding with %u bytes of entropy\n", | |
1160 | entropylen * 2); | |
1161 | } | |
1162 | } | |
1163 | list_add_tail(&data1.list, &seedlist); | |
1164 | ||
1165 | /* | |
1166 | * concatenation of entropy with personalization str / addtl input) | |
1167 | * the variable pers is directly handed in by the caller, so check its | |
1168 | * contents whether it is appropriate | |
1169 | */ | |
1170 | if (pers && pers->buf && 0 < pers->len) { | |
1171 | list_add_tail(&pers->list, &seedlist); | |
1172 | pr_devel("DRBG: using personalization string\n"); | |
1173 | } | |
1174 | ||
1175 | if (!reseed) { | |
1176 | memset(drbg->V, 0, drbg_statelen(drbg)); | |
1177 | memset(drbg->C, 0, drbg_statelen(drbg)); | |
1178 | } | |
1179 | ||
1180 | ret = __drbg_seed(drbg, &seedlist, reseed); | |
1181 | ||
1182 | memzero_explicit(entropy, entropylen * 2); | |
1183 | ||
1184 | return ret; | |
1185 | } | |
1186 | ||
1187 | /* Free all substructures in a DRBG state without the DRBG state structure */ | |
1188 | static inline void drbg_dealloc_state(struct drbg_state *drbg) | |
1189 | { | |
1190 | if (!drbg) | |
1191 | return; | |
1192 | kzfree(drbg->V); | |
1193 | drbg->V = NULL; | |
1194 | kzfree(drbg->C); | |
1195 | drbg->C = NULL; | |
1196 | kzfree(drbg->scratchpad); | |
1197 | drbg->scratchpad = NULL; | |
1198 | drbg->reseed_ctr = 0; | |
1199 | drbg->d_ops = NULL; | |
1200 | drbg->core = NULL; | |
1201 | #ifdef CONFIG_CRYPTO_FIPS | |
1202 | kzfree(drbg->prev); | |
1203 | drbg->prev = NULL; | |
1204 | drbg->fips_primed = false; | |
1205 | #endif | |
1206 | } | |
1207 | ||
1208 | /* | |
1209 | * Allocate all sub-structures for a DRBG state. | |
1210 | * The DRBG state structure must already be allocated. | |
1211 | */ | |
1212 | static inline int drbg_alloc_state(struct drbg_state *drbg) | |
1213 | { | |
1214 | int ret = -ENOMEM; | |
1215 | unsigned int sb_size = 0; | |
1216 | ||
1217 | switch (drbg->core->flags & DRBG_TYPE_MASK) { | |
1218 | #ifdef CONFIG_CRYPTO_DRBG_HMAC | |
1219 | case DRBG_HMAC: | |
1220 | drbg->d_ops = &drbg_hmac_ops; | |
1221 | break; | |
1222 | #endif /* CONFIG_CRYPTO_DRBG_HMAC */ | |
1223 | #ifdef CONFIG_CRYPTO_DRBG_HASH | |
1224 | case DRBG_HASH: | |
1225 | drbg->d_ops = &drbg_hash_ops; | |
1226 | break; | |
1227 | #endif /* CONFIG_CRYPTO_DRBG_HASH */ | |
1228 | #ifdef CONFIG_CRYPTO_DRBG_CTR | |
1229 | case DRBG_CTR: | |
1230 | drbg->d_ops = &drbg_ctr_ops; | |
1231 | break; | |
1232 | #endif /* CONFIG_CRYPTO_DRBG_CTR */ | |
1233 | default: | |
1234 | ret = -EOPNOTSUPP; | |
1235 | goto err; | |
1236 | } | |
1237 | ||
1238 | drbg->V = kmalloc(drbg_statelen(drbg), GFP_KERNEL); | |
1239 | if (!drbg->V) | |
1240 | goto err; | |
1241 | drbg->C = kmalloc(drbg_statelen(drbg), GFP_KERNEL); | |
1242 | if (!drbg->C) | |
1243 | goto err; | |
1244 | #ifdef CONFIG_CRYPTO_FIPS | |
1245 | drbg->prev = kmalloc(drbg_blocklen(drbg), GFP_KERNEL); | |
1246 | if (!drbg->prev) | |
1247 | goto err; | |
1248 | drbg->fips_primed = false; | |
1249 | #endif | |
1250 | /* scratchpad is only generated for CTR and Hash */ | |
1251 | if (drbg->core->flags & DRBG_HMAC) | |
1252 | sb_size = 0; | |
1253 | else if (drbg->core->flags & DRBG_CTR) | |
1254 | sb_size = drbg_statelen(drbg) + drbg_blocklen(drbg) + /* temp */ | |
1255 | drbg_statelen(drbg) + /* df_data */ | |
1256 | drbg_blocklen(drbg) + /* pad */ | |
1257 | drbg_blocklen(drbg) + /* iv */ | |
1258 | drbg_statelen(drbg) + drbg_blocklen(drbg); /* temp */ | |
1259 | else | |
1260 | sb_size = drbg_statelen(drbg) + drbg_blocklen(drbg); | |
1261 | ||
1262 | if (0 < sb_size) { | |
1263 | drbg->scratchpad = kzalloc(sb_size, GFP_KERNEL); | |
1264 | if (!drbg->scratchpad) | |
1265 | goto err; | |
1266 | } | |
1267 | ||
1268 | return 0; | |
1269 | ||
1270 | err: | |
1271 | drbg_dealloc_state(drbg); | |
1272 | return ret; | |
1273 | } | |
1274 | ||
1275 | /************************************************************************* | |
1276 | * DRBG interface functions | |
1277 | *************************************************************************/ | |
1278 | ||
1279 | /* | |
1280 | * DRBG generate function as required by SP800-90A - this function | |
1281 | * generates random numbers | |
1282 | * | |
1283 | * @drbg DRBG state handle | |
1284 | * @buf Buffer where to store the random numbers -- the buffer must already | |
1285 | * be pre-allocated by caller | |
1286 | * @buflen Length of output buffer - this value defines the number of random | |
1287 | * bytes pulled from DRBG | |
1288 | * @addtl Additional input that is mixed into state, may be NULL -- note | |
1289 | * the entropy is pulled by the DRBG internally unconditionally | |
1290 | * as defined in SP800-90A. The additional input is mixed into | |
1291 | * the state in addition to the pulled entropy. | |
1292 | * | |
1293 | * return: 0 when all bytes are generated; < 0 in case of an error | |
1294 | */ | |
1295 | static int drbg_generate(struct drbg_state *drbg, | |
1296 | unsigned char *buf, unsigned int buflen, | |
1297 | struct drbg_string *addtl) | |
1298 | { | |
1299 | int len = 0; | |
1300 | LIST_HEAD(addtllist); | |
1301 | ||
1302 | if (!drbg->core) { | |
1303 | pr_devel("DRBG: not yet seeded\n"); | |
1304 | return -EINVAL; | |
1305 | } | |
1306 | if (0 == buflen || !buf) { | |
1307 | pr_devel("DRBG: no output buffer provided\n"); | |
1308 | return -EINVAL; | |
1309 | } | |
1310 | if (addtl && NULL == addtl->buf && 0 < addtl->len) { | |
1311 | pr_devel("DRBG: wrong format of additional information\n"); | |
1312 | return -EINVAL; | |
1313 | } | |
1314 | ||
1315 | /* 9.3.1 step 2 */ | |
1316 | len = -EINVAL; | |
1317 | if (buflen > (drbg_max_request_bytes(drbg))) { | |
1318 | pr_devel("DRBG: requested random numbers too large %u\n", | |
1319 | buflen); | |
1320 | goto err; | |
1321 | } | |
1322 | ||
1323 | /* 9.3.1 step 3 is implicit with the chosen DRBG */ | |
1324 | ||
1325 | /* 9.3.1 step 4 */ | |
1326 | if (addtl && addtl->len > (drbg_max_addtl(drbg))) { | |
1327 | pr_devel("DRBG: additional information string too long %zu\n", | |
1328 | addtl->len); | |
1329 | goto err; | |
1330 | } | |
1331 | /* 9.3.1 step 5 is implicit with the chosen DRBG */ | |
1332 | ||
1333 | /* | |
1334 | * 9.3.1 step 6 and 9 supplemented by 9.3.2 step c is implemented | |
1335 | * here. The spec is a bit convoluted here, we make it simpler. | |
1336 | */ | |
1337 | if ((drbg_max_requests(drbg)) < drbg->reseed_ctr) | |
1338 | drbg->seeded = false; | |
1339 | ||
1340 | if (drbg->pr || !drbg->seeded) { | |
1341 | pr_devel("DRBG: reseeding before generation (prediction " | |
1342 | "resistance: %s, state %s)\n", | |
1343 | drbg->pr ? "true" : "false", | |
1344 | drbg->seeded ? "seeded" : "unseeded"); | |
1345 | /* 9.3.1 steps 7.1 through 7.3 */ | |
1346 | len = drbg_seed(drbg, addtl, true); | |
1347 | if (len) | |
1348 | goto err; | |
1349 | /* 9.3.1 step 7.4 */ | |
1350 | addtl = NULL; | |
1351 | } | |
1352 | ||
1353 | if (addtl && 0 < addtl->len) | |
1354 | list_add_tail(&addtl->list, &addtllist); | |
1355 | /* 9.3.1 step 8 and 10 */ | |
1356 | len = drbg->d_ops->generate(drbg, buf, buflen, &addtllist); | |
1357 | ||
1358 | /* 10.1.1.4 step 6, 10.1.2.5 step 7, 10.2.1.5.2 step 7 */ | |
1359 | drbg->reseed_ctr++; | |
1360 | if (0 >= len) | |
1361 | goto err; | |
1362 | ||
1363 | /* | |
1364 | * Section 11.3.3 requires to re-perform self tests after some | |
1365 | * generated random numbers. The chosen value after which self | |
1366 | * test is performed is arbitrary, but it should be reasonable. | |
1367 | * However, we do not perform the self tests because of the following | |
1368 | * reasons: it is mathematically impossible that the initial self tests | |
1369 | * were successfully and the following are not. If the initial would | |
1370 | * pass and the following would not, the kernel integrity is violated. | |
1371 | * In this case, the entire kernel operation is questionable and it | |
1372 | * is unlikely that the integrity violation only affects the | |
1373 | * correct operation of the DRBG. | |
1374 | * | |
1375 | * Albeit the following code is commented out, it is provided in | |
1376 | * case somebody has a need to implement the test of 11.3.3. | |
1377 | */ | |
1378 | #if 0 | |
1379 | if (drbg->reseed_ctr && !(drbg->reseed_ctr % 4096)) { | |
1380 | int err = 0; | |
1381 | pr_devel("DRBG: start to perform self test\n"); | |
1382 | if (drbg->core->flags & DRBG_HMAC) | |
1383 | err = alg_test("drbg_pr_hmac_sha256", | |
1384 | "drbg_pr_hmac_sha256", 0, 0); | |
1385 | else if (drbg->core->flags & DRBG_CTR) | |
1386 | err = alg_test("drbg_pr_ctr_aes128", | |
1387 | "drbg_pr_ctr_aes128", 0, 0); | |
1388 | else | |
1389 | err = alg_test("drbg_pr_sha256", | |
1390 | "drbg_pr_sha256", 0, 0); | |
1391 | if (err) { | |
1392 | pr_err("DRBG: periodical self test failed\n"); | |
1393 | /* | |
1394 | * uninstantiate implies that from now on, only errors | |
1395 | * are returned when reusing this DRBG cipher handle | |
1396 | */ | |
1397 | drbg_uninstantiate(drbg); | |
1398 | return 0; | |
1399 | } else { | |
1400 | pr_devel("DRBG: self test successful\n"); | |
1401 | } | |
1402 | } | |
1403 | #endif | |
1404 | ||
1405 | /* | |
1406 | * All operations were successful, return 0 as mandated by | |
1407 | * the kernel crypto API interface. | |
1408 | */ | |
1409 | len = 0; | |
1410 | err: | |
1411 | return len; | |
1412 | } | |
1413 | ||
1414 | /* | |
1415 | * Wrapper around drbg_generate which can pull arbitrary long strings | |
1416 | * from the DRBG without hitting the maximum request limitation. | |
1417 | * | |
1418 | * Parameters: see drbg_generate | |
1419 | * Return codes: see drbg_generate -- if one drbg_generate request fails, | |
1420 | * the entire drbg_generate_long request fails | |
1421 | */ | |
1422 | static int drbg_generate_long(struct drbg_state *drbg, | |
1423 | unsigned char *buf, unsigned int buflen, | |
1424 | struct drbg_string *addtl) | |
1425 | { | |
1426 | unsigned int len = 0; | |
1427 | unsigned int slice = 0; | |
1428 | do { | |
1429 | int err = 0; | |
1430 | unsigned int chunk = 0; | |
1431 | slice = ((buflen - len) / drbg_max_request_bytes(drbg)); | |
1432 | chunk = slice ? drbg_max_request_bytes(drbg) : (buflen - len); | |
1433 | mutex_lock(&drbg->drbg_mutex); | |
1434 | err = drbg_generate(drbg, buf + len, chunk, addtl); | |
1435 | mutex_unlock(&drbg->drbg_mutex); | |
1436 | if (0 > err) | |
1437 | return err; | |
1438 | len += chunk; | |
1439 | } while (slice > 0 && (len < buflen)); | |
1440 | return 0; | |
1441 | } | |
1442 | ||
1443 | static void drbg_schedule_async_seed(struct random_ready_callback *rdy) | |
1444 | { | |
1445 | struct drbg_state *drbg = container_of(rdy, struct drbg_state, | |
1446 | random_ready); | |
1447 | ||
1448 | schedule_work(&drbg->seed_work); | |
1449 | } | |
1450 | ||
1451 | static int drbg_prepare_hrng(struct drbg_state *drbg) | |
1452 | { | |
1453 | int err; | |
1454 | ||
1455 | /* We do not need an HRNG in test mode. */ | |
1456 | if (list_empty(&drbg->test_data.list)) | |
1457 | return 0; | |
1458 | ||
1459 | INIT_WORK(&drbg->seed_work, drbg_async_seed); | |
1460 | ||
1461 | drbg->random_ready.owner = THIS_MODULE; | |
1462 | drbg->random_ready.func = drbg_schedule_async_seed; | |
1463 | ||
1464 | err = add_random_ready_callback(&drbg->random_ready); | |
1465 | ||
1466 | switch (err) { | |
1467 | case 0: | |
1468 | break; | |
1469 | ||
1470 | case -EALREADY: | |
1471 | err = 0; | |
1472 | /* fall through */ | |
1473 | ||
1474 | default: | |
1475 | drbg->random_ready.func = NULL; | |
1476 | return err; | |
1477 | } | |
1478 | ||
1479 | drbg->jent = crypto_alloc_rng("jitterentropy_rng", 0, 0); | |
1480 | ||
1481 | return err; | |
1482 | } | |
1483 | ||
1484 | /* | |
1485 | * DRBG instantiation function as required by SP800-90A - this function | |
1486 | * sets up the DRBG handle, performs the initial seeding and all sanity | |
1487 | * checks required by SP800-90A | |
1488 | * | |
1489 | * @drbg memory of state -- if NULL, new memory is allocated | |
1490 | * @pers Personalization string that is mixed into state, may be NULL -- note | |
1491 | * the entropy is pulled by the DRBG internally unconditionally | |
1492 | * as defined in SP800-90A. The additional input is mixed into | |
1493 | * the state in addition to the pulled entropy. | |
1494 | * @coreref reference to core | |
1495 | * @pr prediction resistance enabled | |
1496 | * | |
1497 | * return | |
1498 | * 0 on success | |
1499 | * error value otherwise | |
1500 | */ | |
1501 | static int drbg_instantiate(struct drbg_state *drbg, struct drbg_string *pers, | |
1502 | int coreref, bool pr) | |
1503 | { | |
1504 | int ret; | |
1505 | bool reseed = true; | |
1506 | ||
1507 | pr_devel("DRBG: Initializing DRBG core %d with prediction resistance " | |
1508 | "%s\n", coreref, pr ? "enabled" : "disabled"); | |
1509 | mutex_lock(&drbg->drbg_mutex); | |
1510 | ||
1511 | /* 9.1 step 1 is implicit with the selected DRBG type */ | |
1512 | ||
1513 | /* | |
1514 | * 9.1 step 2 is implicit as caller can select prediction resistance | |
1515 | * and the flag is copied into drbg->flags -- | |
1516 | * all DRBG types support prediction resistance | |
1517 | */ | |
1518 | ||
1519 | /* 9.1 step 4 is implicit in drbg_sec_strength */ | |
1520 | ||
1521 | if (!drbg->core) { | |
1522 | drbg->core = &drbg_cores[coreref]; | |
1523 | drbg->pr = pr; | |
1524 | drbg->seeded = false; | |
1525 | ||
1526 | ret = drbg_alloc_state(drbg); | |
1527 | if (ret) | |
1528 | goto unlock; | |
1529 | ||
1530 | ret = -EFAULT; | |
1531 | if (drbg->d_ops->crypto_init(drbg)) | |
1532 | goto err; | |
1533 | ||
1534 | ret = drbg_prepare_hrng(drbg); | |
1535 | if (ret) | |
1536 | goto free_everything; | |
1537 | ||
1538 | if (IS_ERR(drbg->jent)) { | |
1539 | ret = PTR_ERR(drbg->jent); | |
1540 | drbg->jent = NULL; | |
1541 | if (fips_enabled || ret != -ENOENT) | |
1542 | goto free_everything; | |
1543 | pr_info("DRBG: Continuing without Jitter RNG\n"); | |
1544 | } | |
1545 | ||
1546 | reseed = false; | |
1547 | } | |
1548 | ||
1549 | ret = drbg_seed(drbg, pers, reseed); | |
1550 | ||
1551 | if (ret && !reseed) | |
1552 | goto free_everything; | |
1553 | ||
1554 | mutex_unlock(&drbg->drbg_mutex); | |
1555 | return ret; | |
1556 | ||
1557 | err: | |
1558 | drbg_dealloc_state(drbg); | |
1559 | unlock: | |
1560 | mutex_unlock(&drbg->drbg_mutex); | |
1561 | return ret; | |
1562 | ||
1563 | free_everything: | |
1564 | mutex_unlock(&drbg->drbg_mutex); | |
1565 | drbg_uninstantiate(drbg); | |
1566 | return ret; | |
1567 | } | |
1568 | ||
1569 | /* | |
1570 | * DRBG uninstantiate function as required by SP800-90A - this function | |
1571 | * frees all buffers and the DRBG handle | |
1572 | * | |
1573 | * @drbg DRBG state handle | |
1574 | * | |
1575 | * return | |
1576 | * 0 on success | |
1577 | */ | |
1578 | static int drbg_uninstantiate(struct drbg_state *drbg) | |
1579 | { | |
1580 | if (drbg->random_ready.func) { | |
1581 | del_random_ready_callback(&drbg->random_ready); | |
1582 | cancel_work_sync(&drbg->seed_work); | |
1583 | crypto_free_rng(drbg->jent); | |
1584 | drbg->jent = NULL; | |
1585 | } | |
1586 | ||
1587 | if (drbg->d_ops) | |
1588 | drbg->d_ops->crypto_fini(drbg); | |
1589 | drbg_dealloc_state(drbg); | |
1590 | /* no scrubbing of test_data -- this shall survive an uninstantiate */ | |
1591 | return 0; | |
1592 | } | |
1593 | ||
1594 | /* | |
1595 | * Helper function for setting the test data in the DRBG | |
1596 | * | |
1597 | * @drbg DRBG state handle | |
1598 | * @data test data | |
1599 | * @len test data length | |
1600 | */ | |
1601 | static void drbg_kcapi_set_entropy(struct crypto_rng *tfm, | |
1602 | const u8 *data, unsigned int len) | |
1603 | { | |
1604 | struct drbg_state *drbg = crypto_rng_ctx(tfm); | |
1605 | ||
1606 | mutex_lock(&drbg->drbg_mutex); | |
1607 | drbg_string_fill(&drbg->test_data, data, len); | |
1608 | mutex_unlock(&drbg->drbg_mutex); | |
1609 | } | |
1610 | ||
1611 | /*************************************************************** | |
1612 | * Kernel crypto API cipher invocations requested by DRBG | |
1613 | ***************************************************************/ | |
1614 | ||
1615 | #if defined(CONFIG_CRYPTO_DRBG_HASH) || defined(CONFIG_CRYPTO_DRBG_HMAC) | |
1616 | struct sdesc { | |
1617 | struct shash_desc shash; | |
1618 | char ctx[]; | |
1619 | }; | |
1620 | ||
1621 | static int drbg_init_hash_kernel(struct drbg_state *drbg) | |
1622 | { | |
1623 | struct sdesc *sdesc; | |
1624 | struct crypto_shash *tfm; | |
1625 | ||
1626 | tfm = crypto_alloc_shash(drbg->core->backend_cra_name, 0, 0); | |
1627 | if (IS_ERR(tfm)) { | |
1628 | pr_info("DRBG: could not allocate digest TFM handle\n"); | |
1629 | return PTR_ERR(tfm); | |
1630 | } | |
1631 | BUG_ON(drbg_blocklen(drbg) != crypto_shash_digestsize(tfm)); | |
1632 | sdesc = kzalloc(sizeof(struct shash_desc) + crypto_shash_descsize(tfm), | |
1633 | GFP_KERNEL); | |
1634 | if (!sdesc) { | |
1635 | crypto_free_shash(tfm); | |
1636 | return -ENOMEM; | |
1637 | } | |
1638 | ||
1639 | sdesc->shash.tfm = tfm; | |
1640 | sdesc->shash.flags = 0; | |
1641 | drbg->priv_data = sdesc; | |
1642 | return 0; | |
1643 | } | |
1644 | ||
1645 | static int drbg_fini_hash_kernel(struct drbg_state *drbg) | |
1646 | { | |
1647 | struct sdesc *sdesc = (struct sdesc *)drbg->priv_data; | |
1648 | if (sdesc) { | |
1649 | crypto_free_shash(sdesc->shash.tfm); | |
1650 | kzfree(sdesc); | |
1651 | } | |
1652 | drbg->priv_data = NULL; | |
1653 | return 0; | |
1654 | } | |
1655 | ||
1656 | static int drbg_kcapi_hash(struct drbg_state *drbg, const unsigned char *key, | |
1657 | unsigned char *outval, const struct list_head *in) | |
1658 | { | |
1659 | struct sdesc *sdesc = (struct sdesc *)drbg->priv_data; | |
1660 | struct drbg_string *input = NULL; | |
1661 | ||
1662 | if (key) | |
1663 | crypto_shash_setkey(sdesc->shash.tfm, key, drbg_statelen(drbg)); | |
1664 | crypto_shash_init(&sdesc->shash); | |
1665 | list_for_each_entry(input, in, list) | |
1666 | crypto_shash_update(&sdesc->shash, input->buf, input->len); | |
1667 | return crypto_shash_final(&sdesc->shash, outval); | |
1668 | } | |
1669 | #endif /* (CONFIG_CRYPTO_DRBG_HASH || CONFIG_CRYPTO_DRBG_HMAC) */ | |
1670 | ||
1671 | #ifdef CONFIG_CRYPTO_DRBG_CTR | |
1672 | static int drbg_init_sym_kernel(struct drbg_state *drbg) | |
1673 | { | |
1674 | int ret = 0; | |
1675 | struct crypto_cipher *tfm; | |
1676 | ||
1677 | tfm = crypto_alloc_cipher(drbg->core->backend_cra_name, 0, 0); | |
1678 | if (IS_ERR(tfm)) { | |
1679 | pr_info("DRBG: could not allocate cipher TFM handle\n"); | |
1680 | return PTR_ERR(tfm); | |
1681 | } | |
1682 | BUG_ON(drbg_blocklen(drbg) != crypto_cipher_blocksize(tfm)); | |
1683 | drbg->priv_data = tfm; | |
1684 | return ret; | |
1685 | } | |
1686 | ||
1687 | static int drbg_fini_sym_kernel(struct drbg_state *drbg) | |
1688 | { | |
1689 | struct crypto_cipher *tfm = | |
1690 | (struct crypto_cipher *)drbg->priv_data; | |
1691 | if (tfm) | |
1692 | crypto_free_cipher(tfm); | |
1693 | drbg->priv_data = NULL; | |
1694 | return 0; | |
1695 | } | |
1696 | ||
1697 | static int drbg_kcapi_sym(struct drbg_state *drbg, const unsigned char *key, | |
1698 | unsigned char *outval, const struct drbg_string *in) | |
1699 | { | |
1700 | struct crypto_cipher *tfm = | |
1701 | (struct crypto_cipher *)drbg->priv_data; | |
1702 | ||
1703 | crypto_cipher_setkey(tfm, key, (drbg_keylen(drbg))); | |
1704 | /* there is only component in *in */ | |
1705 | BUG_ON(in->len < drbg_blocklen(drbg)); | |
1706 | crypto_cipher_encrypt_one(tfm, outval, in->buf); | |
1707 | return 0; | |
1708 | } | |
1709 | #endif /* CONFIG_CRYPTO_DRBG_CTR */ | |
1710 | ||
1711 | /*************************************************************** | |
1712 | * Kernel crypto API interface to register DRBG | |
1713 | ***************************************************************/ | |
1714 | ||
1715 | /* | |
1716 | * Look up the DRBG flags by given kernel crypto API cra_name | |
1717 | * The code uses the drbg_cores definition to do this | |
1718 | * | |
1719 | * @cra_name kernel crypto API cra_name | |
1720 | * @coreref reference to integer which is filled with the pointer to | |
1721 | * the applicable core | |
1722 | * @pr reference for setting prediction resistance | |
1723 | * | |
1724 | * return: flags | |
1725 | */ | |
1726 | static inline void drbg_convert_tfm_core(const char *cra_driver_name, | |
1727 | int *coreref, bool *pr) | |
1728 | { | |
1729 | int i = 0; | |
1730 | size_t start = 0; | |
1731 | int len = 0; | |
1732 | ||
1733 | *pr = true; | |
1734 | /* disassemble the names */ | |
1735 | if (!memcmp(cra_driver_name, "drbg_nopr_", 10)) { | |
1736 | start = 10; | |
1737 | *pr = false; | |
1738 | } else if (!memcmp(cra_driver_name, "drbg_pr_", 8)) { | |
1739 | start = 8; | |
1740 | } else { | |
1741 | return; | |
1742 | } | |
1743 | ||
1744 | /* remove the first part */ | |
1745 | len = strlen(cra_driver_name) - start; | |
1746 | for (i = 0; ARRAY_SIZE(drbg_cores) > i; i++) { | |
1747 | if (!memcmp(cra_driver_name + start, drbg_cores[i].cra_name, | |
1748 | len)) { | |
1749 | *coreref = i; | |
1750 | return; | |
1751 | } | |
1752 | } | |
1753 | } | |
1754 | ||
1755 | static int drbg_kcapi_init(struct crypto_tfm *tfm) | |
1756 | { | |
1757 | struct drbg_state *drbg = crypto_tfm_ctx(tfm); | |
1758 | ||
1759 | mutex_init(&drbg->drbg_mutex); | |
1760 | ||
1761 | return 0; | |
1762 | } | |
1763 | ||
1764 | static void drbg_kcapi_cleanup(struct crypto_tfm *tfm) | |
1765 | { | |
1766 | drbg_uninstantiate(crypto_tfm_ctx(tfm)); | |
1767 | } | |
1768 | ||
1769 | /* | |
1770 | * Generate random numbers invoked by the kernel crypto API: | |
1771 | * The API of the kernel crypto API is extended as follows: | |
1772 | * | |
1773 | * src is additional input supplied to the RNG. | |
1774 | * slen is the length of src. | |
1775 | * dst is the output buffer where random data is to be stored. | |
1776 | * dlen is the length of dst. | |
1777 | */ | |
1778 | static int drbg_kcapi_random(struct crypto_rng *tfm, | |
1779 | const u8 *src, unsigned int slen, | |
1780 | u8 *dst, unsigned int dlen) | |
1781 | { | |
1782 | struct drbg_state *drbg = crypto_rng_ctx(tfm); | |
1783 | struct drbg_string *addtl = NULL; | |
1784 | struct drbg_string string; | |
1785 | ||
1786 | if (slen) { | |
1787 | /* linked list variable is now local to allow modification */ | |
1788 | drbg_string_fill(&string, src, slen); | |
1789 | addtl = &string; | |
1790 | } | |
1791 | ||
1792 | return drbg_generate_long(drbg, dst, dlen, addtl); | |
1793 | } | |
1794 | ||
1795 | /* | |
1796 | * Seed the DRBG invoked by the kernel crypto API | |
1797 | */ | |
1798 | static int drbg_kcapi_seed(struct crypto_rng *tfm, | |
1799 | const u8 *seed, unsigned int slen) | |
1800 | { | |
1801 | struct drbg_state *drbg = crypto_rng_ctx(tfm); | |
1802 | struct crypto_tfm *tfm_base = crypto_rng_tfm(tfm); | |
1803 | bool pr = false; | |
1804 | struct drbg_string string; | |
1805 | struct drbg_string *seed_string = NULL; | |
1806 | int coreref = 0; | |
1807 | ||
1808 | drbg_convert_tfm_core(crypto_tfm_alg_driver_name(tfm_base), &coreref, | |
1809 | &pr); | |
1810 | if (0 < slen) { | |
1811 | drbg_string_fill(&string, seed, slen); | |
1812 | seed_string = &string; | |
1813 | } | |
1814 | ||
1815 | return drbg_instantiate(drbg, seed_string, coreref, pr); | |
1816 | } | |
1817 | ||
1818 | /*************************************************************** | |
1819 | * Kernel module: code to load the module | |
1820 | ***************************************************************/ | |
1821 | ||
1822 | /* | |
1823 | * Tests as defined in 11.3.2 in addition to the cipher tests: testing | |
1824 | * of the error handling. | |
1825 | * | |
1826 | * Note: testing of failing seed source as defined in 11.3.2 is not applicable | |
1827 | * as seed source of get_random_bytes does not fail. | |
1828 | * | |
1829 | * Note 2: There is no sensible way of testing the reseed counter | |
1830 | * enforcement, so skip it. | |
1831 | */ | |
1832 | static inline int __init drbg_healthcheck_sanity(void) | |
1833 | { | |
1834 | int len = 0; | |
1835 | #define OUTBUFLEN 16 | |
1836 | unsigned char buf[OUTBUFLEN]; | |
1837 | struct drbg_state *drbg = NULL; | |
1838 | int ret = -EFAULT; | |
1839 | int rc = -EFAULT; | |
1840 | bool pr = false; | |
1841 | int coreref = 0; | |
1842 | struct drbg_string addtl; | |
1843 | size_t max_addtllen, max_request_bytes; | |
1844 | ||
1845 | /* only perform test in FIPS mode */ | |
1846 | if (!fips_enabled) | |
1847 | return 0; | |
1848 | ||
1849 | #ifdef CONFIG_CRYPTO_DRBG_CTR | |
1850 | drbg_convert_tfm_core("drbg_nopr_ctr_aes128", &coreref, &pr); | |
1851 | #elif defined CONFIG_CRYPTO_DRBG_HASH | |
1852 | drbg_convert_tfm_core("drbg_nopr_sha256", &coreref, &pr); | |
1853 | #else | |
1854 | drbg_convert_tfm_core("drbg_nopr_hmac_sha256", &coreref, &pr); | |
1855 | #endif | |
1856 | ||
1857 | drbg = kzalloc(sizeof(struct drbg_state), GFP_KERNEL); | |
1858 | if (!drbg) | |
1859 | return -ENOMEM; | |
1860 | ||
1861 | mutex_init(&drbg->drbg_mutex); | |
1862 | ||
1863 | /* | |
1864 | * if the following tests fail, it is likely that there is a buffer | |
1865 | * overflow as buf is much smaller than the requested or provided | |
1866 | * string lengths -- in case the error handling does not succeed | |
1867 | * we may get an OOPS. And we want to get an OOPS as this is a | |
1868 | * grave bug. | |
1869 | */ | |
1870 | ||
1871 | /* get a valid instance of DRBG for following tests */ | |
1872 | ret = drbg_instantiate(drbg, NULL, coreref, pr); | |
1873 | if (ret) { | |
1874 | rc = ret; | |
1875 | goto outbuf; | |
1876 | } | |
1877 | max_addtllen = drbg_max_addtl(drbg); | |
1878 | max_request_bytes = drbg_max_request_bytes(drbg); | |
1879 | drbg_string_fill(&addtl, buf, max_addtllen + 1); | |
1880 | /* overflow addtllen with additonal info string */ | |
1881 | len = drbg_generate(drbg, buf, OUTBUFLEN, &addtl); | |
1882 | BUG_ON(0 < len); | |
1883 | /* overflow max_bits */ | |
1884 | len = drbg_generate(drbg, buf, (max_request_bytes + 1), NULL); | |
1885 | BUG_ON(0 < len); | |
1886 | drbg_uninstantiate(drbg); | |
1887 | ||
1888 | /* overflow max addtllen with personalization string */ | |
1889 | ret = drbg_instantiate(drbg, &addtl, coreref, pr); | |
1890 | BUG_ON(0 == ret); | |
1891 | /* all tests passed */ | |
1892 | rc = 0; | |
1893 | ||
1894 | pr_devel("DRBG: Sanity tests for failure code paths successfully " | |
1895 | "completed\n"); | |
1896 | ||
1897 | drbg_uninstantiate(drbg); | |
1898 | outbuf: | |
1899 | kzfree(drbg); | |
1900 | return rc; | |
1901 | } | |
1902 | ||
1903 | static struct rng_alg drbg_algs[22]; | |
1904 | ||
1905 | /* | |
1906 | * Fill the array drbg_algs used to register the different DRBGs | |
1907 | * with the kernel crypto API. To fill the array, the information | |
1908 | * from drbg_cores[] is used. | |
1909 | */ | |
1910 | static inline void __init drbg_fill_array(struct rng_alg *alg, | |
1911 | const struct drbg_core *core, int pr) | |
1912 | { | |
1913 | int pos = 0; | |
1914 | static int priority = 200; | |
1915 | ||
1916 | memcpy(alg->base.cra_name, "stdrng", 6); | |
1917 | if (pr) { | |
1918 | memcpy(alg->base.cra_driver_name, "drbg_pr_", 8); | |
1919 | pos = 8; | |
1920 | } else { | |
1921 | memcpy(alg->base.cra_driver_name, "drbg_nopr_", 10); | |
1922 | pos = 10; | |
1923 | } | |
1924 | memcpy(alg->base.cra_driver_name + pos, core->cra_name, | |
1925 | strlen(core->cra_name)); | |
1926 | ||
1927 | alg->base.cra_priority = priority; | |
1928 | priority++; | |
1929 | /* | |
1930 | * If FIPS mode enabled, the selected DRBG shall have the | |
1931 | * highest cra_priority over other stdrng instances to ensure | |
1932 | * it is selected. | |
1933 | */ | |
1934 | if (fips_enabled) | |
1935 | alg->base.cra_priority += 200; | |
1936 | ||
1937 | alg->base.cra_ctxsize = sizeof(struct drbg_state); | |
1938 | alg->base.cra_module = THIS_MODULE; | |
1939 | alg->base.cra_init = drbg_kcapi_init; | |
1940 | alg->base.cra_exit = drbg_kcapi_cleanup; | |
1941 | alg->generate = drbg_kcapi_random; | |
1942 | alg->seed = drbg_kcapi_seed; | |
1943 | alg->set_ent = drbg_kcapi_set_entropy; | |
1944 | alg->seedsize = 0; | |
1945 | } | |
1946 | ||
1947 | static int __init drbg_init(void) | |
1948 | { | |
1949 | unsigned int i = 0; /* pointer to drbg_algs */ | |
1950 | unsigned int j = 0; /* pointer to drbg_cores */ | |
1951 | int ret = -EFAULT; | |
1952 | ||
1953 | ret = drbg_healthcheck_sanity(); | |
1954 | if (ret) | |
1955 | return ret; | |
1956 | ||
1957 | if (ARRAY_SIZE(drbg_cores) * 2 > ARRAY_SIZE(drbg_algs)) { | |
1958 | pr_info("DRBG: Cannot register all DRBG types" | |
1959 | "(slots needed: %zu, slots available: %zu)\n", | |
1960 | ARRAY_SIZE(drbg_cores) * 2, ARRAY_SIZE(drbg_algs)); | |
1961 | return ret; | |
1962 | } | |
1963 | ||
1964 | /* | |
1965 | * each DRBG definition can be used with PR and without PR, thus | |
1966 | * we instantiate each DRBG in drbg_cores[] twice. | |
1967 | * | |
1968 | * As the order of placing them into the drbg_algs array matters | |
1969 | * (the later DRBGs receive a higher cra_priority) we register the | |
1970 | * prediction resistance DRBGs first as the should not be too | |
1971 | * interesting. | |
1972 | */ | |
1973 | for (j = 0; ARRAY_SIZE(drbg_cores) > j; j++, i++) | |
1974 | drbg_fill_array(&drbg_algs[i], &drbg_cores[j], 1); | |
1975 | for (j = 0; ARRAY_SIZE(drbg_cores) > j; j++, i++) | |
1976 | drbg_fill_array(&drbg_algs[i], &drbg_cores[j], 0); | |
1977 | return crypto_register_rngs(drbg_algs, (ARRAY_SIZE(drbg_cores) * 2)); | |
1978 | } | |
1979 | ||
1980 | static void __exit drbg_exit(void) | |
1981 | { | |
1982 | crypto_unregister_rngs(drbg_algs, (ARRAY_SIZE(drbg_cores) * 2)); | |
1983 | } | |
1984 | ||
1985 | module_init(drbg_init); | |
1986 | module_exit(drbg_exit); | |
1987 | #ifndef CRYPTO_DRBG_HASH_STRING | |
1988 | #define CRYPTO_DRBG_HASH_STRING "" | |
1989 | #endif | |
1990 | #ifndef CRYPTO_DRBG_HMAC_STRING | |
1991 | #define CRYPTO_DRBG_HMAC_STRING "" | |
1992 | #endif | |
1993 | #ifndef CRYPTO_DRBG_CTR_STRING | |
1994 | #define CRYPTO_DRBG_CTR_STRING "" | |
1995 | #endif | |
1996 | MODULE_LICENSE("GPL"); | |
1997 | MODULE_AUTHOR("Stephan Mueller <smueller@chronox.de>"); | |
1998 | MODULE_DESCRIPTION("NIST SP800-90A Deterministic Random Bit Generator (DRBG) " | |
1999 | "using following cores: " | |
2000 | CRYPTO_DRBG_HASH_STRING | |
2001 | CRYPTO_DRBG_HMAC_STRING | |
2002 | CRYPTO_DRBG_CTR_STRING); | |
2003 | MODULE_ALIAS_CRYPTO("stdrng"); |