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541af946 SM |
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 | #if !defined(CONFIG_CRYPTO_DRBG_HASH) && \ | |
103 | !defined(CONFIG_CRYPTO_DRBG_HMAC) && \ | |
104 | !defined(CONFIG_CRYPTO_DRBG_CTR) | |
105 | #warning "The DRBG code is useless without compiling at least one DRBG type" | |
106 | #endif | |
107 | ||
108 | /*************************************************************** | |
109 | * Backend cipher definitions available to DRBG | |
110 | ***************************************************************/ | |
111 | ||
112 | /* | |
113 | * The order of the DRBG definitions here matter: every DRBG is registered | |
114 | * as stdrng. Each DRBG receives an increasing cra_priority values the later | |
115 | * they are defined in this array (see drbg_fill_array). | |
116 | * | |
117 | * HMAC DRBGs are favored over Hash DRBGs over CTR DRBGs, and | |
118 | * the SHA256 / AES 256 over other ciphers. Thus, the favored | |
119 | * DRBGs are the latest entries in this array. | |
120 | */ | |
121 | static const struct drbg_core drbg_cores[] = { | |
122 | #ifdef CONFIG_CRYPTO_DRBG_CTR | |
123 | { | |
124 | .flags = DRBG_CTR | DRBG_STRENGTH128, | |
125 | .statelen = 32, /* 256 bits as defined in 10.2.1 */ | |
126 | .max_addtllen = 35, | |
127 | .max_bits = 19, | |
128 | .max_req = 48, | |
129 | .blocklen_bytes = 16, | |
130 | .cra_name = "ctr_aes128", | |
131 | .backend_cra_name = "ecb(aes)", | |
132 | }, { | |
133 | .flags = DRBG_CTR | DRBG_STRENGTH192, | |
134 | .statelen = 40, /* 320 bits as defined in 10.2.1 */ | |
135 | .max_addtllen = 35, | |
136 | .max_bits = 19, | |
137 | .max_req = 48, | |
138 | .blocklen_bytes = 16, | |
139 | .cra_name = "ctr_aes192", | |
140 | .backend_cra_name = "ecb(aes)", | |
141 | }, { | |
142 | .flags = DRBG_CTR | DRBG_STRENGTH256, | |
143 | .statelen = 48, /* 384 bits as defined in 10.2.1 */ | |
144 | .max_addtllen = 35, | |
145 | .max_bits = 19, | |
146 | .max_req = 48, | |
147 | .blocklen_bytes = 16, | |
148 | .cra_name = "ctr_aes256", | |
149 | .backend_cra_name = "ecb(aes)", | |
150 | }, | |
151 | #endif /* CONFIG_CRYPTO_DRBG_CTR */ | |
152 | #ifdef CONFIG_CRYPTO_DRBG_HASH | |
153 | { | |
154 | .flags = DRBG_HASH | DRBG_STRENGTH128, | |
155 | .statelen = 55, /* 440 bits */ | |
156 | .max_addtllen = 35, | |
157 | .max_bits = 19, | |
158 | .max_req = 48, | |
159 | .blocklen_bytes = 20, | |
160 | .cra_name = "sha1", | |
161 | .backend_cra_name = "sha1", | |
162 | }, { | |
163 | .flags = DRBG_HASH | DRBG_STRENGTH256, | |
164 | .statelen = 111, /* 888 bits */ | |
165 | .max_addtllen = 35, | |
166 | .max_bits = 19, | |
167 | .max_req = 48, | |
168 | .blocklen_bytes = 48, | |
169 | .cra_name = "sha384", | |
170 | .backend_cra_name = "sha384", | |
171 | }, { | |
172 | .flags = DRBG_HASH | DRBG_STRENGTH256, | |
173 | .statelen = 111, /* 888 bits */ | |
174 | .max_addtllen = 35, | |
175 | .max_bits = 19, | |
176 | .max_req = 48, | |
177 | .blocklen_bytes = 64, | |
178 | .cra_name = "sha512", | |
179 | .backend_cra_name = "sha512", | |
180 | }, { | |
181 | .flags = DRBG_HASH | DRBG_STRENGTH256, | |
182 | .statelen = 55, /* 440 bits */ | |
183 | .max_addtllen = 35, | |
184 | .max_bits = 19, | |
185 | .max_req = 48, | |
186 | .blocklen_bytes = 32, | |
187 | .cra_name = "sha256", | |
188 | .backend_cra_name = "sha256", | |
189 | }, | |
190 | #endif /* CONFIG_CRYPTO_DRBG_HASH */ | |
191 | #ifdef CONFIG_CRYPTO_DRBG_HMAC | |
192 | { | |
193 | .flags = DRBG_HMAC | DRBG_STRENGTH256, | |
194 | .statelen = 20, /* block length of cipher */ | |
195 | .max_addtllen = 35, | |
196 | .max_bits = 19, | |
197 | .max_req = 48, | |
198 | .blocklen_bytes = 20, | |
199 | .cra_name = "hmac_sha1", | |
200 | .backend_cra_name = "hmac(sha1)", | |
201 | }, { | |
202 | .flags = DRBG_HMAC | DRBG_STRENGTH256, | |
203 | .statelen = 48, /* block length of cipher */ | |
204 | .max_addtllen = 35, | |
205 | .max_bits = 19, | |
206 | .max_req = 48, | |
207 | .blocklen_bytes = 48, | |
208 | .cra_name = "hmac_sha384", | |
209 | .backend_cra_name = "hmac(sha384)", | |
210 | }, { | |
211 | .flags = DRBG_HMAC | DRBG_STRENGTH256, | |
212 | .statelen = 64, /* block length of cipher */ | |
213 | .max_addtllen = 35, | |
214 | .max_bits = 19, | |
215 | .max_req = 48, | |
216 | .blocklen_bytes = 64, | |
217 | .cra_name = "hmac_sha512", | |
218 | .backend_cra_name = "hmac(sha512)", | |
219 | }, { | |
220 | .flags = DRBG_HMAC | DRBG_STRENGTH256, | |
221 | .statelen = 32, /* block length of cipher */ | |
222 | .max_addtllen = 35, | |
223 | .max_bits = 19, | |
224 | .max_req = 48, | |
225 | .blocklen_bytes = 32, | |
226 | .cra_name = "hmac_sha256", | |
227 | .backend_cra_name = "hmac(sha256)", | |
228 | }, | |
229 | #endif /* CONFIG_CRYPTO_DRBG_HMAC */ | |
230 | }; | |
231 | ||
232 | /****************************************************************** | |
233 | * Generic helper functions | |
234 | ******************************************************************/ | |
235 | ||
236 | /* | |
237 | * Return strength of DRBG according to SP800-90A section 8.4 | |
238 | * | |
239 | * @flags DRBG flags reference | |
240 | * | |
241 | * Return: normalized strength in *bytes* value or 32 as default | |
242 | * to counter programming errors | |
243 | */ | |
244 | static inline unsigned short drbg_sec_strength(drbg_flag_t flags) | |
245 | { | |
246 | switch (flags & DRBG_STRENGTH_MASK) { | |
247 | case DRBG_STRENGTH128: | |
248 | return 16; | |
249 | case DRBG_STRENGTH192: | |
250 | return 24; | |
251 | case DRBG_STRENGTH256: | |
252 | return 32; | |
253 | default: | |
254 | return 32; | |
255 | } | |
256 | } | |
257 | ||
258 | /* | |
259 | * FIPS 140-2 continuous self test | |
260 | * The test is performed on the result of one round of the output | |
261 | * function. Thus, the function implicitly knows the size of the | |
262 | * buffer. | |
263 | * | |
264 | * The FIPS test can be called in an endless loop until it returns | |
265 | * true. Although the code looks like a potential for a deadlock, it | |
266 | * is not the case, because returning a false cannot mathematically | |
267 | * occur (except once when a reseed took place and the updated state | |
268 | * would is now set up such that the generation of new value returns | |
269 | * an identical one -- this is most unlikely and would happen only once). | |
270 | * Thus, if this function repeatedly returns false and thus would cause | |
271 | * a deadlock, the integrity of the entire kernel is lost. | |
272 | * | |
273 | * @drbg DRBG handle | |
274 | * @buf output buffer of random data to be checked | |
275 | * | |
276 | * return: | |
277 | * true on success | |
278 | * false on error | |
279 | */ | |
280 | static bool drbg_fips_continuous_test(struct drbg_state *drbg, | |
281 | const unsigned char *buf) | |
282 | { | |
283 | #ifdef CONFIG_CRYPTO_FIPS | |
284 | int ret = 0; | |
285 | /* skip test if we test the overall system */ | |
286 | if (drbg->test_data) | |
287 | return true; | |
288 | /* only perform test in FIPS mode */ | |
289 | if (0 == fips_enabled) | |
290 | return true; | |
291 | if (!drbg->fips_primed) { | |
292 | /* Priming of FIPS test */ | |
293 | memcpy(drbg->prev, buf, drbg_blocklen(drbg)); | |
294 | drbg->fips_primed = true; | |
295 | /* return false due to priming, i.e. another round is needed */ | |
296 | return false; | |
297 | } | |
298 | ret = memcmp(drbg->prev, buf, drbg_blocklen(drbg)); | |
299 | memcpy(drbg->prev, buf, drbg_blocklen(drbg)); | |
300 | /* the test shall pass when the two compared values are not equal */ | |
301 | return ret != 0; | |
302 | #else | |
303 | return true; | |
304 | #endif /* CONFIG_CRYPTO_FIPS */ | |
305 | } | |
306 | ||
307 | /* | |
308 | * Convert an integer into a byte representation of this integer. | |
309 | * The byte representation is big-endian | |
310 | * | |
311 | * @buf buffer holding the converted integer | |
312 | * @val value to be converted | |
313 | * @buflen length of buffer | |
314 | */ | |
315 | #if (defined(CONFIG_CRYPTO_DRBG_HASH) || defined(CONFIG_CRYPTO_DRBG_CTR)) | |
316 | static inline void drbg_int2byte(unsigned char *buf, uint64_t val, | |
317 | size_t buflen) | |
318 | { | |
319 | unsigned char *byte; | |
320 | uint64_t i; | |
321 | ||
322 | byte = buf + (buflen - 1); | |
323 | for (i = 0; i < buflen; i++) | |
324 | *(byte--) = val >> (i * 8) & 0xff; | |
325 | } | |
326 | ||
327 | /* | |
328 | * Increment buffer | |
329 | * | |
330 | * @dst buffer to increment | |
331 | * @add value to add | |
332 | */ | |
333 | static inline void drbg_add_buf(unsigned char *dst, size_t dstlen, | |
334 | const unsigned char *add, size_t addlen) | |
335 | { | |
336 | /* implied: dstlen > addlen */ | |
337 | unsigned char *dstptr; | |
338 | const unsigned char *addptr; | |
339 | unsigned int remainder = 0; | |
340 | size_t len = addlen; | |
341 | ||
342 | dstptr = dst + (dstlen-1); | |
343 | addptr = add + (addlen-1); | |
344 | while (len) { | |
345 | remainder += *dstptr + *addptr; | |
346 | *dstptr = remainder & 0xff; | |
347 | remainder >>= 8; | |
348 | len--; dstptr--; addptr--; | |
349 | } | |
350 | len = dstlen - addlen; | |
351 | while (len && remainder > 0) { | |
352 | remainder = *dstptr + 1; | |
353 | *dstptr = remainder & 0xff; | |
354 | remainder >>= 8; | |
355 | len--; dstptr--; | |
356 | } | |
357 | } | |
358 | #endif /* defined(CONFIG_CRYPTO_DRBG_HASH) || defined(CONFIG_CRYPTO_DRBG_CTR) */ | |
359 | ||
360 | /****************************************************************** | |
361 | * CTR DRBG callback functions | |
362 | ******************************************************************/ | |
363 | ||
364 | #ifdef CONFIG_CRYPTO_DRBG_CTR | |
365 | static int drbg_kcapi_sym(struct drbg_state *drbg, const unsigned char *key, | |
366 | unsigned char *outval, const struct drbg_string *in); | |
367 | static int drbg_init_sym_kernel(struct drbg_state *drbg); | |
368 | static int drbg_fini_sym_kernel(struct drbg_state *drbg); | |
369 | ||
370 | /* BCC function for CTR DRBG as defined in 10.4.3 */ | |
371 | static int drbg_ctr_bcc(struct drbg_state *drbg, | |
372 | unsigned char *out, const unsigned char *key, | |
373 | struct drbg_string *in) | |
374 | { | |
375 | int ret = -EFAULT; | |
376 | struct drbg_string *curr = in; | |
377 | size_t inpos = curr->len; | |
378 | const unsigned char *pos = curr->buf; | |
379 | struct drbg_string data; | |
380 | ||
381 | drbg_string_fill(&data, out, drbg_blocklen(drbg)); | |
382 | ||
383 | /* 10.4.3 step 1 */ | |
384 | memset(out, 0, drbg_blocklen(drbg)); | |
385 | ||
386 | /* 10.4.3 step 2 / 4 */ | |
387 | while (inpos) { | |
388 | short cnt = 0; | |
389 | /* 10.4.3 step 4.1 */ | |
390 | for (cnt = 0; cnt < drbg_blocklen(drbg); cnt++) { | |
391 | out[cnt] ^= *pos; | |
392 | pos++; inpos--; | |
393 | /* | |
394 | * The following branch implements the linked list | |
395 | * iteration of drbg_string *in. If we are at the | |
396 | * end of the current list member, we have to start | |
397 | * using the next member if available. The inpos | |
398 | * value always points to the current byte and will | |
399 | * be zero if we have processed the last byte of | |
400 | * the last linked list member. | |
401 | */ | |
402 | if (0 == inpos) { | |
403 | curr = curr->next; | |
404 | if (NULL != curr) { | |
405 | pos = curr->buf; | |
406 | inpos = curr->len; | |
407 | } else { | |
408 | inpos = 0; | |
409 | break; | |
410 | } | |
411 | } | |
412 | } | |
413 | /* 10.4.3 step 4.2 */ | |
414 | ret = drbg_kcapi_sym(drbg, key, out, &data); | |
415 | if (ret) | |
416 | return ret; | |
417 | /* 10.4.3 step 2 */ | |
418 | } | |
419 | return 0; | |
420 | } | |
421 | ||
422 | /* | |
423 | * scratchpad usage: drbg_ctr_update is interlinked with drbg_ctr_df | |
424 | * (and drbg_ctr_bcc, but this function does not need any temporary buffers), | |
425 | * the scratchpad is used as follows: | |
426 | * drbg_ctr_update: | |
427 | * temp | |
428 | * start: drbg->scratchpad | |
429 | * length: drbg_statelen(drbg) + drbg_blocklen(drbg) | |
430 | * note: the cipher writing into this variable works | |
431 | * blocklen-wise. Now, when the statelen is not a multiple | |
432 | * of blocklen, the generateion loop below "spills over" | |
433 | * by at most blocklen. Thus, we need to give sufficient | |
434 | * memory. | |
435 | * df_data | |
436 | * start: drbg->scratchpad + | |
437 | * drbg_statelen(drbg) + drbg_blocklen(drbg) | |
438 | * length: drbg_statelen(drbg) | |
439 | * | |
440 | * drbg_ctr_df: | |
441 | * pad | |
442 | * start: df_data + drbg_statelen(drbg) | |
443 | * length: drbg_blocklen(drbg) | |
444 | * iv | |
445 | * start: pad + drbg_blocklen(drbg) | |
446 | * length: drbg_blocklen(drbg) | |
447 | * temp | |
448 | * start: iv + drbg_blocklen(drbg) | |
8fecaad7 SM |
449 | * length: drbg_satelen(drbg) + drbg_blocklen(drbg) |
450 | * note: temp is the buffer that the BCC function operates | |
451 | * on. BCC operates blockwise. drbg_statelen(drbg) | |
452 | * is sufficient when the DRBG state length is a multiple | |
453 | * of the block size. For AES192 (and maybe other ciphers) | |
454 | * this is not correct and the length for temp is | |
455 | * insufficient (yes, that also means for such ciphers, | |
456 | * the final output of all BCC rounds are truncated). | |
457 | * Therefore, add drbg_blocklen(drbg) to cover all | |
458 | * possibilities. | |
541af946 SM |
459 | */ |
460 | ||
461 | /* Derivation Function for CTR DRBG as defined in 10.4.2 */ | |
462 | static int drbg_ctr_df(struct drbg_state *drbg, | |
463 | unsigned char *df_data, size_t bytes_to_return, | |
464 | struct drbg_string *addtl) | |
465 | { | |
466 | int ret = -EFAULT; | |
467 | unsigned char L_N[8]; | |
468 | /* S3 is input */ | |
469 | struct drbg_string S1, S2, S4, cipherin; | |
470 | struct drbg_string *tempstr = addtl; | |
471 | unsigned char *pad = df_data + drbg_statelen(drbg); | |
472 | unsigned char *iv = pad + drbg_blocklen(drbg); | |
473 | unsigned char *temp = iv + drbg_blocklen(drbg); | |
474 | size_t padlen = 0; | |
475 | unsigned int templen = 0; | |
476 | /* 10.4.2 step 7 */ | |
477 | unsigned int i = 0; | |
478 | /* 10.4.2 step 8 */ | |
479 | const unsigned char *K = (unsigned char *) | |
480 | "\x00\x01\x02\x03\x04\x05\x06\x07" | |
481 | "\x08\x09\x0a\x0b\x0c\x0d\x0e\x0f" | |
482 | "\x10\x11\x12\x13\x14\x15\x16\x17" | |
483 | "\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f"; | |
484 | unsigned char *X; | |
485 | size_t generated_len = 0; | |
486 | size_t inputlen = 0; | |
487 | ||
488 | memset(pad, 0, drbg_blocklen(drbg)); | |
489 | memset(iv, 0, drbg_blocklen(drbg)); | |
490 | memset(temp, 0, drbg_statelen(drbg)); | |
491 | ||
492 | /* 10.4.2 step 1 is implicit as we work byte-wise */ | |
493 | ||
494 | /* 10.4.2 step 2 */ | |
495 | if ((512/8) < bytes_to_return) | |
496 | return -EINVAL; | |
497 | ||
498 | /* 10.4.2 step 2 -- calculate the entire length of all input data */ | |
499 | for (; NULL != tempstr; tempstr = tempstr->next) | |
500 | inputlen += tempstr->len; | |
501 | drbg_int2byte(&L_N[0], inputlen, 4); | |
502 | ||
503 | /* 10.4.2 step 3 */ | |
504 | drbg_int2byte(&L_N[4], bytes_to_return, 4); | |
505 | ||
506 | /* 10.4.2 step 5: length is L_N, input_string, one byte, padding */ | |
507 | padlen = (inputlen + sizeof(L_N) + 1) % (drbg_blocklen(drbg)); | |
508 | /* wrap the padlen appropriately */ | |
509 | if (padlen) | |
510 | padlen = drbg_blocklen(drbg) - padlen; | |
511 | /* | |
512 | * pad / padlen contains the 0x80 byte and the following zero bytes. | |
513 | * As the calculated padlen value only covers the number of zero | |
514 | * bytes, this value has to be incremented by one for the 0x80 byte. | |
515 | */ | |
516 | padlen++; | |
517 | pad[0] = 0x80; | |
518 | ||
519 | /* 10.4.2 step 4 -- first fill the linked list and then order it */ | |
520 | drbg_string_fill(&S1, iv, drbg_blocklen(drbg)); | |
521 | drbg_string_fill(&S2, L_N, sizeof(L_N)); | |
522 | drbg_string_fill(&S4, pad, padlen); | |
523 | S1.next = &S2; | |
524 | S2.next = addtl; | |
525 | ||
526 | /* | |
c0eedf80 SM |
527 | * Splice in addtl between S2 and S4 -- we place S4 at the end |
528 | * of the input data chain. As this code is only triggered when | |
529 | * addtl is not NULL, no NULL checks are necessary. | |
541af946 SM |
530 | */ |
531 | tempstr = addtl; | |
c0eedf80 SM |
532 | while (tempstr->next) |
533 | tempstr = tempstr->next; | |
541af946 SM |
534 | tempstr->next = &S4; |
535 | ||
536 | /* 10.4.2 step 9 */ | |
537 | while (templen < (drbg_keylen(drbg) + (drbg_blocklen(drbg)))) { | |
538 | /* | |
539 | * 10.4.2 step 9.1 - the padding is implicit as the buffer | |
540 | * holds zeros after allocation -- even the increment of i | |
541 | * is irrelevant as the increment remains within length of i | |
542 | */ | |
543 | drbg_int2byte(iv, i, 4); | |
544 | /* 10.4.2 step 9.2 -- BCC and concatenation with temp */ | |
545 | ret = drbg_ctr_bcc(drbg, temp + templen, K, &S1); | |
546 | if (ret) | |
547 | goto out; | |
548 | /* 10.4.2 step 9.3 */ | |
549 | i++; | |
550 | templen += drbg_blocklen(drbg); | |
551 | } | |
552 | ||
553 | /* 10.4.2 step 11 */ | |
554 | X = temp + (drbg_keylen(drbg)); | |
555 | drbg_string_fill(&cipherin, X, drbg_blocklen(drbg)); | |
556 | ||
557 | /* 10.4.2 step 12: overwriting of outval is implemented in next step */ | |
558 | ||
559 | /* 10.4.2 step 13 */ | |
560 | while (generated_len < bytes_to_return) { | |
561 | short blocklen = 0; | |
562 | /* | |
563 | * 10.4.2 step 13.1: the truncation of the key length is | |
564 | * implicit as the key is only drbg_blocklen in size based on | |
565 | * the implementation of the cipher function callback | |
566 | */ | |
567 | ret = drbg_kcapi_sym(drbg, temp, X, &cipherin); | |
568 | if (ret) | |
569 | goto out; | |
570 | blocklen = (drbg_blocklen(drbg) < | |
571 | (bytes_to_return - generated_len)) ? | |
572 | drbg_blocklen(drbg) : | |
573 | (bytes_to_return - generated_len); | |
574 | /* 10.4.2 step 13.2 and 14 */ | |
575 | memcpy(df_data + generated_len, X, blocklen); | |
576 | generated_len += blocklen; | |
577 | } | |
578 | ||
579 | ret = 0; | |
580 | ||
581 | out: | |
582 | memset(iv, 0, drbg_blocklen(drbg)); | |
583 | memset(temp, 0, drbg_statelen(drbg)); | |
584 | memset(pad, 0, drbg_blocklen(drbg)); | |
585 | return ret; | |
586 | } | |
587 | ||
588 | /* update function of CTR DRBG as defined in 10.2.1.2 */ | |
589 | static int drbg_ctr_update(struct drbg_state *drbg, | |
590 | struct drbg_string *addtl, int reseed) | |
591 | { | |
592 | int ret = -EFAULT; | |
593 | /* 10.2.1.2 step 1 */ | |
594 | unsigned char *temp = drbg->scratchpad; | |
595 | unsigned char *df_data = drbg->scratchpad + drbg_statelen(drbg) + | |
596 | drbg_blocklen(drbg); | |
597 | unsigned char *temp_p, *df_data_p; /* pointer to iterate over buffers */ | |
598 | unsigned int len = 0; | |
599 | struct drbg_string cipherin; | |
600 | unsigned char prefix = DRBG_PREFIX1; | |
601 | ||
602 | memset(temp, 0, drbg_statelen(drbg) + drbg_blocklen(drbg)); | |
603 | memset(df_data, 0, drbg_statelen(drbg)); | |
604 | ||
605 | /* 10.2.1.3.2 step 2 and 10.2.1.4.2 step 2 */ | |
606 | if (addtl && 0 < addtl->len) { | |
607 | ret = drbg_ctr_df(drbg, df_data, drbg_statelen(drbg), | |
608 | addtl); | |
609 | if (ret) | |
610 | goto out; | |
611 | } | |
612 | ||
613 | drbg_string_fill(&cipherin, drbg->V, drbg_blocklen(drbg)); | |
614 | /* | |
615 | * 10.2.1.3.2 steps 2 and 3 are already covered as the allocation | |
616 | * zeroizes all memory during initialization | |
617 | */ | |
618 | while (len < (drbg_statelen(drbg))) { | |
619 | /* 10.2.1.2 step 2.1 */ | |
620 | drbg_add_buf(drbg->V, drbg_blocklen(drbg), &prefix, 1); | |
621 | /* | |
622 | * 10.2.1.2 step 2.2 */ | |
623 | ret = drbg_kcapi_sym(drbg, drbg->C, temp + len, &cipherin); | |
624 | if (ret) | |
625 | goto out; | |
626 | /* 10.2.1.2 step 2.3 and 3 */ | |
627 | len += drbg_blocklen(drbg); | |
628 | } | |
629 | ||
630 | /* 10.2.1.2 step 4 */ | |
631 | temp_p = temp; | |
632 | df_data_p = df_data; | |
633 | for (len = 0; len < drbg_statelen(drbg); len++) { | |
634 | *temp_p ^= *df_data_p; | |
635 | df_data_p++; temp_p++; | |
636 | } | |
637 | ||
638 | /* 10.2.1.2 step 5 */ | |
639 | memcpy(drbg->C, temp, drbg_keylen(drbg)); | |
640 | /* 10.2.1.2 step 6 */ | |
641 | memcpy(drbg->V, temp + drbg_keylen(drbg), drbg_blocklen(drbg)); | |
642 | ret = 0; | |
643 | ||
644 | out: | |
645 | memset(temp, 0, drbg_statelen(drbg) + drbg_blocklen(drbg)); | |
646 | memset(df_data, 0, drbg_statelen(drbg)); | |
647 | return ret; | |
648 | } | |
649 | ||
650 | /* | |
651 | * scratchpad use: drbg_ctr_update is called independently from | |
652 | * drbg_ctr_extract_bytes. Therefore, the scratchpad is reused | |
653 | */ | |
654 | /* Generate function of CTR DRBG as defined in 10.2.1.5.2 */ | |
655 | static int drbg_ctr_generate(struct drbg_state *drbg, | |
656 | unsigned char *buf, unsigned int buflen, | |
657 | struct drbg_string *addtl) | |
658 | { | |
659 | int len = 0; | |
660 | int ret = 0; | |
661 | struct drbg_string data; | |
662 | unsigned char prefix = DRBG_PREFIX1; | |
663 | ||
664 | memset(drbg->scratchpad, 0, drbg_blocklen(drbg)); | |
665 | ||
666 | /* 10.2.1.5.2 step 2 */ | |
667 | if (addtl && 0 < addtl->len) { | |
668 | addtl->next = NULL; | |
669 | ret = drbg_ctr_update(drbg, addtl, 1); | |
670 | if (ret) | |
671 | return 0; | |
672 | } | |
673 | ||
674 | /* 10.2.1.5.2 step 4.1 */ | |
675 | drbg_add_buf(drbg->V, drbg_blocklen(drbg), &prefix, 1); | |
676 | drbg_string_fill(&data, drbg->V, drbg_blocklen(drbg)); | |
677 | while (len < buflen) { | |
678 | int outlen = 0; | |
679 | /* 10.2.1.5.2 step 4.2 */ | |
680 | ret = drbg_kcapi_sym(drbg, drbg->C, drbg->scratchpad, &data); | |
681 | if (ret) { | |
682 | len = ret; | |
683 | goto out; | |
684 | } | |
685 | outlen = (drbg_blocklen(drbg) < (buflen - len)) ? | |
686 | drbg_blocklen(drbg) : (buflen - len); | |
687 | if (!drbg_fips_continuous_test(drbg, drbg->scratchpad)) { | |
688 | /* 10.2.1.5.2 step 6 */ | |
689 | drbg_add_buf(drbg->V, drbg_blocklen(drbg), &prefix, 1); | |
690 | continue; | |
691 | } | |
692 | /* 10.2.1.5.2 step 4.3 */ | |
693 | memcpy(buf + len, drbg->scratchpad, outlen); | |
694 | len += outlen; | |
695 | /* 10.2.1.5.2 step 6 */ | |
696 | if (len < buflen) | |
697 | drbg_add_buf(drbg->V, drbg_blocklen(drbg), &prefix, 1); | |
698 | } | |
699 | ||
700 | /* 10.2.1.5.2 step 6 */ | |
701 | if (addtl) | |
702 | addtl->next = NULL; | |
703 | /* | |
704 | * The following call invokes the DF function again which could be | |
705 | * optimized. In step 2, the "additional_input" after step 2 is the | |
706 | * output of the DF function. If this result would be saved, the DF | |
707 | * function would not need to be invoked again at this point. | |
708 | */ | |
709 | ret = drbg_ctr_update(drbg, addtl, 1); | |
710 | if (ret) | |
711 | len = ret; | |
712 | ||
713 | out: | |
714 | memset(drbg->scratchpad, 0, drbg_blocklen(drbg)); | |
715 | return len; | |
716 | } | |
717 | ||
718 | static struct drbg_state_ops drbg_ctr_ops = { | |
719 | .update = drbg_ctr_update, | |
720 | .generate = drbg_ctr_generate, | |
721 | .crypto_init = drbg_init_sym_kernel, | |
722 | .crypto_fini = drbg_fini_sym_kernel, | |
723 | }; | |
724 | #endif /* CONFIG_CRYPTO_DRBG_CTR */ | |
725 | ||
726 | /****************************************************************** | |
727 | * HMAC DRBG callback functions | |
728 | ******************************************************************/ | |
729 | ||
730 | #if defined(CONFIG_CRYPTO_DRBG_HASH) || defined(CONFIG_CRYPTO_DRBG_HMAC) | |
731 | static int drbg_kcapi_hash(struct drbg_state *drbg, const unsigned char *key, | |
732 | unsigned char *outval, const struct drbg_string *in); | |
733 | static int drbg_init_hash_kernel(struct drbg_state *drbg); | |
734 | static int drbg_fini_hash_kernel(struct drbg_state *drbg); | |
735 | #endif /* (CONFIG_CRYPTO_DRBG_HASH || CONFIG_CRYPTO_DRBG_HMAC) */ | |
736 | ||
737 | #ifdef CONFIG_CRYPTO_DRBG_HMAC | |
738 | /* update function of HMAC DRBG as defined in 10.1.2.2 */ | |
739 | static int drbg_hmac_update(struct drbg_state *drbg, | |
740 | struct drbg_string *seed, int reseed) | |
741 | { | |
742 | int ret = -EFAULT; | |
743 | int i = 0; | |
744 | struct drbg_string seed1, seed2, cipherin; | |
745 | ||
746 | if (!reseed) { | |
747 | /* 10.1.2.3 step 2 */ | |
748 | memset(drbg->C, 0, drbg_statelen(drbg)); | |
749 | memset(drbg->V, 1, drbg_statelen(drbg)); | |
750 | } | |
751 | ||
752 | drbg_string_fill(&seed1, drbg->V, drbg_statelen(drbg)); | |
753 | /* buffer of seed2 will be filled in for loop below with one byte */ | |
754 | drbg_string_fill(&seed2, NULL, 1); | |
755 | seed1.next = &seed2; | |
756 | /* input data of seed is allowed to be NULL at this point */ | |
757 | seed2.next = seed; | |
758 | ||
759 | drbg_string_fill(&cipherin, drbg->V, drbg_statelen(drbg)); | |
760 | for (i = 2; 0 < i; i--) { | |
761 | /* first round uses 0x0, second 0x1 */ | |
762 | unsigned char prefix = DRBG_PREFIX0; | |
763 | if (1 == i) | |
764 | prefix = DRBG_PREFIX1; | |
765 | /* 10.1.2.2 step 1 and 4 -- concatenation and HMAC for key */ | |
766 | seed2.buf = &prefix; | |
767 | ret = drbg_kcapi_hash(drbg, drbg->C, drbg->C, &seed1); | |
768 | if (ret) | |
769 | return ret; | |
770 | ||
771 | /* 10.1.2.2 step 2 and 5 -- HMAC for V */ | |
772 | ret = drbg_kcapi_hash(drbg, drbg->C, drbg->V, &cipherin); | |
773 | if (ret) | |
774 | return ret; | |
775 | ||
776 | /* 10.1.2.2 step 3 */ | |
777 | if (!seed || 0 == seed->len) | |
778 | return ret; | |
779 | } | |
780 | ||
781 | return 0; | |
782 | } | |
783 | ||
784 | /* generate function of HMAC DRBG as defined in 10.1.2.5 */ | |
785 | static int drbg_hmac_generate(struct drbg_state *drbg, | |
786 | unsigned char *buf, | |
787 | unsigned int buflen, | |
788 | struct drbg_string *addtl) | |
789 | { | |
790 | int len = 0; | |
791 | int ret = 0; | |
792 | struct drbg_string data; | |
793 | ||
794 | /* 10.1.2.5 step 2 */ | |
795 | if (addtl && 0 < addtl->len) { | |
796 | addtl->next = NULL; | |
797 | ret = drbg_hmac_update(drbg, addtl, 1); | |
798 | if (ret) | |
799 | return ret; | |
800 | } | |
801 | ||
802 | drbg_string_fill(&data, drbg->V, drbg_statelen(drbg)); | |
803 | while (len < buflen) { | |
804 | unsigned int outlen = 0; | |
805 | /* 10.1.2.5 step 4.1 */ | |
806 | ret = drbg_kcapi_hash(drbg, drbg->C, drbg->V, &data); | |
807 | if (ret) | |
808 | return ret; | |
809 | outlen = (drbg_blocklen(drbg) < (buflen - len)) ? | |
810 | drbg_blocklen(drbg) : (buflen - len); | |
811 | if (!drbg_fips_continuous_test(drbg, drbg->V)) | |
812 | continue; | |
813 | ||
814 | /* 10.1.2.5 step 4.2 */ | |
815 | memcpy(buf + len, drbg->V, outlen); | |
816 | len += outlen; | |
817 | } | |
818 | ||
819 | /* 10.1.2.5 step 6 */ | |
820 | if (addtl) | |
821 | addtl->next = NULL; | |
822 | ret = drbg_hmac_update(drbg, addtl, 1); | |
823 | if (ret) | |
824 | return ret; | |
825 | ||
826 | return len; | |
827 | } | |
828 | ||
829 | static struct drbg_state_ops drbg_hmac_ops = { | |
830 | .update = drbg_hmac_update, | |
831 | .generate = drbg_hmac_generate, | |
832 | .crypto_init = drbg_init_hash_kernel, | |
833 | .crypto_fini = drbg_fini_hash_kernel, | |
834 | ||
835 | }; | |
836 | #endif /* CONFIG_CRYPTO_DRBG_HMAC */ | |
837 | ||
838 | /****************************************************************** | |
839 | * Hash DRBG callback functions | |
840 | ******************************************************************/ | |
841 | ||
842 | #ifdef CONFIG_CRYPTO_DRBG_HASH | |
843 | /* | |
844 | * scratchpad usage: as drbg_hash_update and drbg_hash_df are used | |
845 | * interlinked, the scratchpad is used as follows: | |
846 | * drbg_hash_update | |
847 | * start: drbg->scratchpad | |
848 | * length: drbg_statelen(drbg) | |
849 | * drbg_hash_df: | |
850 | * start: drbg->scratchpad + drbg_statelen(drbg) | |
851 | * length: drbg_blocklen(drbg) | |
852 | * | |
853 | * drbg_hash_process_addtl uses the scratchpad, but fully completes | |
854 | * before either of the functions mentioned before are invoked. Therefore, | |
855 | * drbg_hash_process_addtl does not need to be specifically considered. | |
856 | */ | |
857 | ||
858 | /* Derivation Function for Hash DRBG as defined in 10.4.1 */ | |
859 | static int drbg_hash_df(struct drbg_state *drbg, | |
860 | unsigned char *outval, size_t outlen, | |
861 | struct drbg_string *entropy) | |
862 | { | |
863 | int ret = 0; | |
864 | size_t len = 0; | |
865 | unsigned char input[5]; | |
866 | unsigned char *tmp = drbg->scratchpad + drbg_statelen(drbg); | |
867 | struct drbg_string data1; | |
868 | ||
869 | memset(tmp, 0, drbg_blocklen(drbg)); | |
870 | ||
871 | /* 10.4.1 step 3 */ | |
872 | input[0] = 1; | |
873 | drbg_int2byte(&input[1], (outlen * 8), 4); | |
874 | ||
875 | /* 10.4.1 step 4.1 -- concatenation of data for input into hash */ | |
876 | drbg_string_fill(&data1, input, 5); | |
877 | data1.next = entropy; | |
878 | ||
879 | /* 10.4.1 step 4 */ | |
880 | while (len < outlen) { | |
881 | short blocklen = 0; | |
882 | /* 10.4.1 step 4.1 */ | |
883 | ret = drbg_kcapi_hash(drbg, NULL, tmp, &data1); | |
884 | if (ret) | |
885 | goto out; | |
886 | /* 10.4.1 step 4.2 */ | |
887 | input[0]++; | |
888 | blocklen = (drbg_blocklen(drbg) < (outlen - len)) ? | |
889 | drbg_blocklen(drbg) : (outlen - len); | |
890 | memcpy(outval + len, tmp, blocklen); | |
891 | len += blocklen; | |
892 | } | |
893 | ||
894 | out: | |
895 | memset(tmp, 0, drbg_blocklen(drbg)); | |
896 | return ret; | |
897 | } | |
898 | ||
899 | /* update function for Hash DRBG as defined in 10.1.1.2 / 10.1.1.3 */ | |
900 | static int drbg_hash_update(struct drbg_state *drbg, struct drbg_string *seed, | |
901 | int reseed) | |
902 | { | |
903 | int ret = 0; | |
904 | struct drbg_string data1, data2; | |
905 | unsigned char *V = drbg->scratchpad; | |
906 | unsigned char prefix = DRBG_PREFIX1; | |
907 | ||
908 | memset(drbg->scratchpad, 0, drbg_statelen(drbg)); | |
909 | if (!seed) | |
910 | return -EINVAL; | |
911 | ||
912 | if (reseed) { | |
913 | /* 10.1.1.3 step 1 */ | |
914 | memcpy(V, drbg->V, drbg_statelen(drbg)); | |
915 | drbg_string_fill(&data1, &prefix, 1); | |
916 | drbg_string_fill(&data2, V, drbg_statelen(drbg)); | |
917 | data1.next = &data2; | |
918 | data2.next = seed; | |
919 | } else { | |
920 | drbg_string_fill(&data1, seed->buf, seed->len); | |
921 | data1.next = seed->next; | |
922 | } | |
923 | ||
924 | /* 10.1.1.2 / 10.1.1.3 step 2 and 3 */ | |
925 | ret = drbg_hash_df(drbg, drbg->V, drbg_statelen(drbg), &data1); | |
926 | if (ret) | |
927 | goto out; | |
928 | ||
929 | /* 10.1.1.2 / 10.1.1.3 step 4 */ | |
930 | prefix = DRBG_PREFIX0; | |
931 | drbg_string_fill(&data1, &prefix, 1); | |
932 | drbg_string_fill(&data2, drbg->V, drbg_statelen(drbg)); | |
933 | data1.next = &data2; | |
934 | /* 10.1.1.2 / 10.1.1.3 step 4 */ | |
935 | ret = drbg_hash_df(drbg, drbg->C, drbg_statelen(drbg), &data1); | |
936 | ||
937 | out: | |
938 | memset(drbg->scratchpad, 0, drbg_statelen(drbg)); | |
939 | return ret; | |
940 | } | |
941 | ||
942 | /* processing of additional information string for Hash DRBG */ | |
943 | static int drbg_hash_process_addtl(struct drbg_state *drbg, | |
944 | struct drbg_string *addtl) | |
945 | { | |
946 | int ret = 0; | |
947 | struct drbg_string data1, data2; | |
948 | struct drbg_string *data3; | |
949 | unsigned char prefix = DRBG_PREFIX2; | |
950 | ||
951 | /* this is value w as per documentation */ | |
952 | memset(drbg->scratchpad, 0, drbg_blocklen(drbg)); | |
953 | ||
954 | /* 10.1.1.4 step 2 */ | |
955 | if (!addtl || 0 == addtl->len) | |
956 | return 0; | |
957 | ||
958 | /* 10.1.1.4 step 2a */ | |
959 | drbg_string_fill(&data1, &prefix, 1); | |
960 | drbg_string_fill(&data2, drbg->V, drbg_statelen(drbg)); | |
961 | data3 = addtl; | |
962 | data1.next = &data2; | |
963 | data2.next = data3; | |
964 | data3->next = NULL; | |
965 | ret = drbg_kcapi_hash(drbg, NULL, drbg->scratchpad, &data1); | |
966 | if (ret) | |
967 | goto out; | |
968 | ||
969 | /* 10.1.1.4 step 2b */ | |
970 | drbg_add_buf(drbg->V, drbg_statelen(drbg), | |
971 | drbg->scratchpad, drbg_blocklen(drbg)); | |
972 | ||
973 | out: | |
974 | memset(drbg->scratchpad, 0, drbg_blocklen(drbg)); | |
975 | return ret; | |
976 | } | |
977 | ||
978 | /* Hashgen defined in 10.1.1.4 */ | |
979 | static int drbg_hash_hashgen(struct drbg_state *drbg, | |
980 | unsigned char *buf, | |
981 | unsigned int buflen) | |
982 | { | |
983 | int len = 0; | |
984 | int ret = 0; | |
985 | unsigned char *src = drbg->scratchpad; | |
986 | unsigned char *dst = drbg->scratchpad + drbg_statelen(drbg); | |
987 | struct drbg_string data; | |
988 | unsigned char prefix = DRBG_PREFIX1; | |
989 | ||
990 | memset(src, 0, drbg_statelen(drbg)); | |
991 | memset(dst, 0, drbg_blocklen(drbg)); | |
992 | ||
993 | /* 10.1.1.4 step hashgen 2 */ | |
994 | memcpy(src, drbg->V, drbg_statelen(drbg)); | |
995 | ||
996 | drbg_string_fill(&data, src, drbg_statelen(drbg)); | |
997 | while (len < buflen) { | |
998 | unsigned int outlen = 0; | |
999 | /* 10.1.1.4 step hashgen 4.1 */ | |
1000 | ret = drbg_kcapi_hash(drbg, NULL, dst, &data); | |
1001 | if (ret) { | |
1002 | len = ret; | |
1003 | goto out; | |
1004 | } | |
1005 | outlen = (drbg_blocklen(drbg) < (buflen - len)) ? | |
1006 | drbg_blocklen(drbg) : (buflen - len); | |
1007 | if (!drbg_fips_continuous_test(drbg, dst)) { | |
1008 | drbg_add_buf(src, drbg_statelen(drbg), &prefix, 1); | |
1009 | continue; | |
1010 | } | |
1011 | /* 10.1.1.4 step hashgen 4.2 */ | |
1012 | memcpy(buf + len, dst, outlen); | |
1013 | len += outlen; | |
1014 | /* 10.1.1.4 hashgen step 4.3 */ | |
1015 | if (len < buflen) | |
1016 | drbg_add_buf(src, drbg_statelen(drbg), &prefix, 1); | |
1017 | } | |
1018 | ||
1019 | out: | |
1020 | memset(drbg->scratchpad, 0, | |
1021 | (drbg_statelen(drbg) + drbg_blocklen(drbg))); | |
1022 | return len; | |
1023 | } | |
1024 | ||
1025 | /* generate function for Hash DRBG as defined in 10.1.1.4 */ | |
1026 | static int drbg_hash_generate(struct drbg_state *drbg, | |
1027 | unsigned char *buf, unsigned int buflen, | |
1028 | struct drbg_string *addtl) | |
1029 | { | |
1030 | int len = 0; | |
1031 | int ret = 0; | |
1032 | unsigned char req[8]; | |
1033 | unsigned char prefix = DRBG_PREFIX3; | |
1034 | struct drbg_string data1, data2; | |
1035 | ||
1036 | /* 10.1.1.4 step 2 */ | |
1037 | ret = drbg_hash_process_addtl(drbg, addtl); | |
1038 | if (ret) | |
1039 | return ret; | |
1040 | /* 10.1.1.4 step 3 */ | |
1041 | len = drbg_hash_hashgen(drbg, buf, buflen); | |
1042 | ||
1043 | /* this is the value H as documented in 10.1.1.4 */ | |
1044 | memset(drbg->scratchpad, 0, drbg_blocklen(drbg)); | |
1045 | /* 10.1.1.4 step 4 */ | |
1046 | drbg_string_fill(&data1, &prefix, 1); | |
1047 | drbg_string_fill(&data2, drbg->V, drbg_statelen(drbg)); | |
1048 | data1.next = &data2; | |
1049 | ret = drbg_kcapi_hash(drbg, NULL, drbg->scratchpad, &data1); | |
1050 | if (ret) { | |
1051 | len = ret; | |
1052 | goto out; | |
1053 | } | |
1054 | ||
1055 | /* 10.1.1.4 step 5 */ | |
1056 | drbg_add_buf(drbg->V, drbg_statelen(drbg), | |
1057 | drbg->scratchpad, drbg_blocklen(drbg)); | |
1058 | drbg_add_buf(drbg->V, drbg_statelen(drbg), | |
1059 | drbg->C, drbg_statelen(drbg)); | |
1060 | drbg_int2byte(req, drbg->reseed_ctr, sizeof(req)); | |
1061 | drbg_add_buf(drbg->V, drbg_statelen(drbg), req, 8); | |
1062 | ||
1063 | out: | |
1064 | memset(drbg->scratchpad, 0, drbg_blocklen(drbg)); | |
1065 | return len; | |
1066 | } | |
1067 | ||
1068 | /* | |
1069 | * scratchpad usage: as update and generate are used isolated, both | |
1070 | * can use the scratchpad | |
1071 | */ | |
1072 | static struct drbg_state_ops drbg_hash_ops = { | |
1073 | .update = drbg_hash_update, | |
1074 | .generate = drbg_hash_generate, | |
1075 | .crypto_init = drbg_init_hash_kernel, | |
1076 | .crypto_fini = drbg_fini_hash_kernel, | |
1077 | }; | |
1078 | #endif /* CONFIG_CRYPTO_DRBG_HASH */ | |
1079 | ||
1080 | /****************************************************************** | |
1081 | * Functions common for DRBG implementations | |
1082 | ******************************************************************/ | |
1083 | ||
1084 | /* | |
1085 | * Seeding or reseeding of the DRBG | |
1086 | * | |
1087 | * @drbg: DRBG state struct | |
1088 | * @pers: personalization / additional information buffer | |
1089 | * @reseed: 0 for initial seed process, 1 for reseeding | |
1090 | * | |
1091 | * return: | |
1092 | * 0 on success | |
1093 | * error value otherwise | |
1094 | */ | |
1095 | static int drbg_seed(struct drbg_state *drbg, struct drbg_string *pers, | |
1096 | bool reseed) | |
1097 | { | |
1098 | int ret = 0; | |
1099 | unsigned char *entropy = NULL; | |
1100 | size_t entropylen = 0; | |
1101 | struct drbg_string data1; | |
1102 | ||
1103 | /* 9.1 / 9.2 / 9.3.1 step 3 */ | |
1104 | if (pers && pers->len > (drbg_max_addtl(drbg))) { | |
1105 | pr_devel("DRBG: personalization string too long %lu\n", | |
1106 | pers->len); | |
1107 | return -EINVAL; | |
1108 | } | |
1109 | ||
1110 | if (drbg->test_data && drbg->test_data->testentropy) { | |
1111 | drbg_string_fill(&data1, drbg->test_data->testentropy->buf, | |
1112 | drbg->test_data->testentropy->len); | |
1113 | pr_devel("DRBG: using test entropy\n"); | |
1114 | } else { | |
1115 | /* | |
1116 | * Gather entropy equal to the security strength of the DRBG. | |
1117 | * With a derivation function, a nonce is required in addition | |
1118 | * to the entropy. A nonce must be at least 1/2 of the security | |
1119 | * strength of the DRBG in size. Thus, entropy * nonce is 3/2 | |
1120 | * of the strength. The consideration of a nonce is only | |
1121 | * applicable during initial seeding. | |
1122 | */ | |
1123 | entropylen = drbg_sec_strength(drbg->core->flags); | |
1124 | if (!entropylen) | |
1125 | return -EFAULT; | |
1126 | if (!reseed) | |
1127 | entropylen = ((entropylen + 1) / 2) * 3; | |
1128 | pr_devel("DRBG: (re)seeding with %zu bytes of entropy\n", | |
1129 | entropylen); | |
1130 | entropy = kzalloc(entropylen, GFP_KERNEL); | |
1131 | if (!entropy) | |
1132 | return -ENOMEM; | |
1133 | get_random_bytes(entropy, entropylen); | |
1134 | drbg_string_fill(&data1, entropy, entropylen); | |
1135 | } | |
1136 | ||
1137 | /* | |
1138 | * concatenation of entropy with personalization str / addtl input) | |
1139 | * the variable pers is directly handed in by the caller, so check its | |
1140 | * contents whether it is appropriate | |
1141 | */ | |
1142 | if (pers && pers->buf && 0 < pers->len && NULL == pers->next) { | |
1143 | data1.next = pers; | |
1144 | pr_devel("DRBG: using personalization string\n"); | |
1145 | } | |
1146 | ||
1147 | ret = drbg->d_ops->update(drbg, &data1, reseed); | |
1148 | if (ret) | |
1149 | goto out; | |
1150 | ||
1151 | drbg->seeded = true; | |
1152 | /* 10.1.1.2 / 10.1.1.3 step 5 */ | |
1153 | drbg->reseed_ctr = 1; | |
1154 | ||
1155 | out: | |
1156 | if (entropy) | |
1157 | kzfree(entropy); | |
1158 | return ret; | |
1159 | } | |
1160 | ||
1161 | /* Free all substructures in a DRBG state without the DRBG state structure */ | |
1162 | static inline void drbg_dealloc_state(struct drbg_state *drbg) | |
1163 | { | |
1164 | if (!drbg) | |
1165 | return; | |
1166 | if (drbg->V) | |
1167 | kzfree(drbg->V); | |
1168 | drbg->V = NULL; | |
1169 | if (drbg->C) | |
1170 | kzfree(drbg->C); | |
1171 | drbg->C = NULL; | |
1172 | if (drbg->scratchpad) | |
1173 | kzfree(drbg->scratchpad); | |
1174 | drbg->scratchpad = NULL; | |
1175 | drbg->reseed_ctr = 0; | |
1176 | #ifdef CONFIG_CRYPTO_FIPS | |
1177 | if (drbg->prev) | |
1178 | kzfree(drbg->prev); | |
1179 | drbg->prev = NULL; | |
1180 | drbg->fips_primed = false; | |
1181 | #endif | |
1182 | } | |
1183 | ||
1184 | /* | |
1185 | * Allocate all sub-structures for a DRBG state. | |
1186 | * The DRBG state structure must already be allocated. | |
1187 | */ | |
1188 | static inline int drbg_alloc_state(struct drbg_state *drbg) | |
1189 | { | |
1190 | int ret = -ENOMEM; | |
1191 | unsigned int sb_size = 0; | |
1192 | ||
1193 | if (!drbg) | |
1194 | return -EINVAL; | |
1195 | ||
1196 | drbg->V = kzalloc(drbg_statelen(drbg), GFP_KERNEL); | |
1197 | if (!drbg->V) | |
1198 | goto err; | |
1199 | drbg->C = kzalloc(drbg_statelen(drbg), GFP_KERNEL); | |
1200 | if (!drbg->C) | |
1201 | goto err; | |
1202 | #ifdef CONFIG_CRYPTO_FIPS | |
1203 | drbg->prev = kzalloc(drbg_blocklen(drbg), GFP_KERNEL); | |
1204 | if (!drbg->prev) | |
1205 | goto err; | |
1206 | drbg->fips_primed = false; | |
1207 | #endif | |
1208 | /* scratchpad is only generated for CTR and Hash */ | |
1209 | if (drbg->core->flags & DRBG_HMAC) | |
1210 | sb_size = 0; | |
1211 | else if (drbg->core->flags & DRBG_CTR) | |
1212 | sb_size = drbg_statelen(drbg) + drbg_blocklen(drbg) + /* temp */ | |
1213 | drbg_statelen(drbg) + /* df_data */ | |
1214 | drbg_blocklen(drbg) + /* pad */ | |
1215 | drbg_blocklen(drbg) + /* iv */ | |
8fecaad7 | 1216 | drbg_statelen(drbg) + drbg_blocklen(drbg); /* temp */ |
541af946 SM |
1217 | else |
1218 | sb_size = drbg_statelen(drbg) + drbg_blocklen(drbg); | |
1219 | ||
1220 | if (0 < sb_size) { | |
1221 | drbg->scratchpad = kzalloc(sb_size, GFP_KERNEL); | |
1222 | if (!drbg->scratchpad) | |
1223 | goto err; | |
1224 | } | |
1225 | spin_lock_init(&drbg->drbg_lock); | |
1226 | return 0; | |
1227 | ||
1228 | err: | |
1229 | drbg_dealloc_state(drbg); | |
1230 | return ret; | |
1231 | } | |
1232 | ||
1233 | /* | |
1234 | * Strategy to avoid holding long term locks: generate a shadow copy of DRBG | |
1235 | * and perform all operations on this shadow copy. After finishing, restore | |
1236 | * the updated state of the shadow copy into original drbg state. This way, | |
1237 | * only the read and write operations of the original drbg state must be | |
1238 | * locked | |
1239 | */ | |
1240 | static inline void drbg_copy_drbg(struct drbg_state *src, | |
1241 | struct drbg_state *dst) | |
1242 | { | |
1243 | if (!src || !dst) | |
1244 | return; | |
1245 | memcpy(dst->V, src->V, drbg_statelen(src)); | |
1246 | memcpy(dst->C, src->C, drbg_statelen(src)); | |
1247 | dst->reseed_ctr = src->reseed_ctr; | |
1248 | dst->seeded = src->seeded; | |
1249 | dst->pr = src->pr; | |
1250 | #ifdef CONFIG_CRYPTO_FIPS | |
1251 | dst->fips_primed = src->fips_primed; | |
1252 | memcpy(dst->prev, src->prev, drbg_blocklen(src)); | |
1253 | #endif | |
1254 | /* | |
1255 | * Not copied: | |
1256 | * scratchpad is initialized drbg_alloc_state; | |
1257 | * priv_data is initialized with call to crypto_init; | |
1258 | * d_ops and core are set outside, as these parameters are const; | |
1259 | * test_data is set outside to prevent it being copied back. | |
1260 | */ | |
1261 | } | |
1262 | ||
1263 | static int drbg_make_shadow(struct drbg_state *drbg, struct drbg_state **shadow) | |
1264 | { | |
1265 | int ret = -ENOMEM; | |
1266 | struct drbg_state *tmp = NULL; | |
1267 | ||
1268 | if (!drbg || !drbg->core || !drbg->V || !drbg->C) { | |
1269 | pr_devel("DRBG: attempt to generate shadow copy for " | |
1270 | "uninitialized DRBG state rejected\n"); | |
1271 | return -EINVAL; | |
1272 | } | |
1273 | /* HMAC does not have a scratchpad */ | |
1274 | if (!(drbg->core->flags & DRBG_HMAC) && NULL == drbg->scratchpad) | |
1275 | return -EINVAL; | |
1276 | ||
1277 | tmp = kzalloc(sizeof(struct drbg_state), GFP_KERNEL); | |
1278 | if (!tmp) | |
1279 | return -ENOMEM; | |
1280 | ||
1281 | /* read-only data as they are defined as const, no lock needed */ | |
1282 | tmp->core = drbg->core; | |
1283 | tmp->d_ops = drbg->d_ops; | |
1284 | ||
1285 | ret = drbg_alloc_state(tmp); | |
1286 | if (ret) | |
1287 | goto err; | |
1288 | ||
1289 | spin_lock_bh(&drbg->drbg_lock); | |
1290 | drbg_copy_drbg(drbg, tmp); | |
1291 | /* only make a link to the test buffer, as we only read that data */ | |
1292 | tmp->test_data = drbg->test_data; | |
1293 | spin_unlock_bh(&drbg->drbg_lock); | |
1294 | *shadow = tmp; | |
1295 | return 0; | |
1296 | ||
1297 | err: | |
1298 | if (tmp) | |
1299 | kzfree(tmp); | |
1300 | return ret; | |
1301 | } | |
1302 | ||
1303 | static void drbg_restore_shadow(struct drbg_state *drbg, | |
1304 | struct drbg_state **shadow) | |
1305 | { | |
1306 | struct drbg_state *tmp = *shadow; | |
1307 | ||
1308 | spin_lock_bh(&drbg->drbg_lock); | |
1309 | drbg_copy_drbg(tmp, drbg); | |
1310 | spin_unlock_bh(&drbg->drbg_lock); | |
1311 | drbg_dealloc_state(tmp); | |
1312 | kzfree(tmp); | |
1313 | *shadow = NULL; | |
1314 | } | |
1315 | ||
1316 | /************************************************************************* | |
1317 | * DRBG interface functions | |
1318 | *************************************************************************/ | |
1319 | ||
1320 | /* | |
1321 | * DRBG generate function as required by SP800-90A - this function | |
1322 | * generates random numbers | |
1323 | * | |
1324 | * @drbg DRBG state handle | |
1325 | * @buf Buffer where to store the random numbers -- the buffer must already | |
1326 | * be pre-allocated by caller | |
1327 | * @buflen Length of output buffer - this value defines the number of random | |
1328 | * bytes pulled from DRBG | |
1329 | * @addtl Additional input that is mixed into state, may be NULL -- note | |
1330 | * the entropy is pulled by the DRBG internally unconditionally | |
1331 | * as defined in SP800-90A. The additional input is mixed into | |
1332 | * the state in addition to the pulled entropy. | |
1333 | * | |
1334 | * return: generated number of bytes | |
1335 | */ | |
1336 | static int drbg_generate(struct drbg_state *drbg, | |
1337 | unsigned char *buf, unsigned int buflen, | |
1338 | struct drbg_string *addtl) | |
1339 | { | |
1340 | int len = 0; | |
1341 | struct drbg_state *shadow = NULL; | |
1342 | ||
1343 | if (0 == buflen || !buf) { | |
1344 | pr_devel("DRBG: no output buffer provided\n"); | |
1345 | return -EINVAL; | |
1346 | } | |
1347 | if (addtl && NULL == addtl->buf && 0 < addtl->len) { | |
1348 | pr_devel("DRBG: wrong format of additional information\n"); | |
1349 | return -EINVAL; | |
1350 | } | |
1351 | ||
1352 | len = drbg_make_shadow(drbg, &shadow); | |
1353 | if (len) { | |
1354 | pr_devel("DRBG: shadow copy cannot be generated\n"); | |
1355 | return len; | |
1356 | } | |
1357 | ||
1358 | /* 9.3.1 step 2 */ | |
1359 | len = -EINVAL; | |
1360 | if (buflen > (drbg_max_request_bytes(shadow))) { | |
1361 | pr_devel("DRBG: requested random numbers too large %u\n", | |
1362 | buflen); | |
1363 | goto err; | |
1364 | } | |
1365 | ||
1366 | /* 9.3.1 step 3 is implicit with the chosen DRBG */ | |
1367 | ||
1368 | /* 9.3.1 step 4 */ | |
1369 | if (addtl && addtl->len > (drbg_max_addtl(shadow))) { | |
1370 | pr_devel("DRBG: additional information string too long %zu\n", | |
1371 | addtl->len); | |
1372 | goto err; | |
1373 | } | |
1374 | /* 9.3.1 step 5 is implicit with the chosen DRBG */ | |
1375 | ||
1376 | /* | |
1377 | * 9.3.1 step 6 and 9 supplemented by 9.3.2 step c is implemented | |
1378 | * here. The spec is a bit convoluted here, we make it simpler. | |
1379 | */ | |
1380 | if ((drbg_max_requests(shadow)) < shadow->reseed_ctr) | |
1381 | shadow->seeded = false; | |
1382 | ||
1383 | /* allocate cipher handle */ | |
1384 | if (shadow->d_ops->crypto_init) { | |
1385 | len = shadow->d_ops->crypto_init(shadow); | |
1386 | if (len) | |
1387 | goto err; | |
1388 | } | |
1389 | ||
1390 | if (shadow->pr || !shadow->seeded) { | |
1391 | pr_devel("DRBG: reseeding before generation (prediction " | |
1392 | "resistance: %s, state %s)\n", | |
1393 | drbg->pr ? "true" : "false", | |
1394 | drbg->seeded ? "seeded" : "unseeded"); | |
1395 | /* 9.3.1 steps 7.1 through 7.3 */ | |
1396 | len = drbg_seed(shadow, addtl, true); | |
1397 | if (len) | |
1398 | goto err; | |
1399 | /* 9.3.1 step 7.4 */ | |
1400 | addtl = NULL; | |
1401 | } | |
1402 | /* 9.3.1 step 8 and 10 */ | |
1403 | len = shadow->d_ops->generate(shadow, buf, buflen, addtl); | |
1404 | ||
1405 | /* 10.1.1.4 step 6, 10.1.2.5 step 7, 10.2.1.5.2 step 7 */ | |
1406 | shadow->reseed_ctr++; | |
1407 | if (0 >= len) | |
1408 | goto err; | |
1409 | ||
1410 | /* | |
1411 | * Section 11.3.3 requires to re-perform self tests after some | |
1412 | * generated random numbers. The chosen value after which self | |
1413 | * test is performed is arbitrary, but it should be reasonable. | |
1414 | * However, we do not perform the self tests because of the following | |
1415 | * reasons: it is mathematically impossible that the initial self tests | |
1416 | * were successfully and the following are not. If the initial would | |
1417 | * pass and the following would not, the kernel integrity is violated. | |
1418 | * In this case, the entire kernel operation is questionable and it | |
1419 | * is unlikely that the integrity violation only affects the | |
1420 | * correct operation of the DRBG. | |
1421 | * | |
1422 | * Albeit the following code is commented out, it is provided in | |
1423 | * case somebody has a need to implement the test of 11.3.3. | |
1424 | */ | |
1425 | #if 0 | |
1426 | if (shadow->reseed_ctr && !(shadow->reseed_ctr % 4096)) { | |
1427 | int err = 0; | |
1428 | pr_devel("DRBG: start to perform self test\n"); | |
1429 | if (drbg->core->flags & DRBG_HMAC) | |
1430 | err = alg_test("drbg_pr_hmac_sha256", | |
1431 | "drbg_pr_hmac_sha256", 0, 0); | |
1432 | else if (drbg->core->flags & DRBG_CTR) | |
1433 | err = alg_test("drbg_pr_ctr_aes128", | |
1434 | "drbg_pr_ctr_aes128", 0, 0); | |
1435 | else | |
1436 | err = alg_test("drbg_pr_sha256", | |
1437 | "drbg_pr_sha256", 0, 0); | |
1438 | if (err) { | |
1439 | pr_err("DRBG: periodical self test failed\n"); | |
1440 | /* | |
1441 | * uninstantiate implies that from now on, only errors | |
1442 | * are returned when reusing this DRBG cipher handle | |
1443 | */ | |
1444 | drbg_uninstantiate(drbg); | |
1445 | drbg_dealloc_state(shadow); | |
1446 | kzfree(shadow); | |
1447 | return 0; | |
1448 | } else { | |
1449 | pr_devel("DRBG: self test successful\n"); | |
1450 | } | |
1451 | } | |
1452 | #endif | |
1453 | ||
1454 | err: | |
1455 | if (shadow->d_ops->crypto_fini) | |
1456 | shadow->d_ops->crypto_fini(shadow); | |
1457 | drbg_restore_shadow(drbg, &shadow); | |
1458 | return len; | |
1459 | } | |
1460 | ||
1461 | /* | |
1462 | * Wrapper around drbg_generate which can pull arbitrary long strings | |
1463 | * from the DRBG without hitting the maximum request limitation. | |
1464 | * | |
1465 | * Parameters: see drbg_generate | |
1466 | * Return codes: see drbg_generate -- if one drbg_generate request fails, | |
1467 | * the entire drbg_generate_long request fails | |
1468 | */ | |
1469 | static int drbg_generate_long(struct drbg_state *drbg, | |
1470 | unsigned char *buf, unsigned int buflen, | |
1471 | struct drbg_string *addtl) | |
1472 | { | |
1473 | int len = 0; | |
1474 | unsigned int slice = 0; | |
1475 | do { | |
1476 | int tmplen = 0; | |
1477 | unsigned int chunk = 0; | |
1478 | slice = ((buflen - len) / drbg_max_request_bytes(drbg)); | |
1479 | chunk = slice ? drbg_max_request_bytes(drbg) : (buflen - len); | |
1480 | tmplen = drbg_generate(drbg, buf + len, chunk, addtl); | |
1481 | if (0 >= tmplen) | |
1482 | return tmplen; | |
1483 | len += tmplen; | |
1484 | } while (slice > 0); | |
1485 | return len; | |
1486 | } | |
1487 | ||
1488 | /* | |
1489 | * DRBG instantiation function as required by SP800-90A - this function | |
1490 | * sets up the DRBG handle, performs the initial seeding and all sanity | |
1491 | * checks required by SP800-90A | |
1492 | * | |
1493 | * @drbg memory of state -- if NULL, new memory is allocated | |
1494 | * @pers Personalization string that is mixed into state, may be NULL -- note | |
1495 | * the entropy is pulled by the DRBG internally unconditionally | |
1496 | * as defined in SP800-90A. The additional input is mixed into | |
1497 | * the state in addition to the pulled entropy. | |
1498 | * @coreref reference to core | |
1499 | * @pr prediction resistance enabled | |
1500 | * | |
1501 | * return | |
1502 | * 0 on success | |
1503 | * error value otherwise | |
1504 | */ | |
1505 | static int drbg_instantiate(struct drbg_state *drbg, struct drbg_string *pers, | |
1506 | int coreref, bool pr) | |
1507 | { | |
1508 | int ret = -ENOMEM; | |
1509 | ||
1510 | pr_devel("DRBG: Initializing DRBG core %d with prediction resistance " | |
1511 | "%s\n", coreref, pr ? "enabled" : "disabled"); | |
1512 | drbg->core = &drbg_cores[coreref]; | |
1513 | drbg->pr = pr; | |
1514 | drbg->seeded = false; | |
1515 | switch (drbg->core->flags & DRBG_TYPE_MASK) { | |
1516 | #ifdef CONFIG_CRYPTO_DRBG_HMAC | |
1517 | case DRBG_HMAC: | |
1518 | drbg->d_ops = &drbg_hmac_ops; | |
1519 | break; | |
1520 | #endif /* CONFIG_CRYPTO_DRBG_HMAC */ | |
1521 | #ifdef CONFIG_CRYPTO_DRBG_HASH | |
1522 | case DRBG_HASH: | |
1523 | drbg->d_ops = &drbg_hash_ops; | |
1524 | break; | |
1525 | #endif /* CONFIG_CRYPTO_DRBG_HASH */ | |
1526 | #ifdef CONFIG_CRYPTO_DRBG_CTR | |
1527 | case DRBG_CTR: | |
1528 | drbg->d_ops = &drbg_ctr_ops; | |
1529 | break; | |
1530 | #endif /* CONFIG_CRYPTO_DRBG_CTR */ | |
1531 | default: | |
1532 | return -EOPNOTSUPP; | |
1533 | } | |
1534 | ||
1535 | /* 9.1 step 1 is implicit with the selected DRBG type */ | |
1536 | ||
1537 | /* | |
1538 | * 9.1 step 2 is implicit as caller can select prediction resistance | |
1539 | * and the flag is copied into drbg->flags -- | |
1540 | * all DRBG types support prediction resistance | |
1541 | */ | |
1542 | ||
1543 | /* 9.1 step 4 is implicit in drbg_sec_strength */ | |
1544 | ||
1545 | ret = drbg_alloc_state(drbg); | |
1546 | if (ret) | |
1547 | return ret; | |
1548 | ||
1549 | ret = -EFAULT; | |
1550 | if (drbg->d_ops->crypto_init && drbg->d_ops->crypto_init(drbg)) | |
1551 | goto err; | |
1552 | ret = drbg_seed(drbg, pers, false); | |
1553 | if (drbg->d_ops->crypto_fini) | |
1554 | drbg->d_ops->crypto_fini(drbg); | |
1555 | if (ret) | |
1556 | goto err; | |
1557 | ||
1558 | return 0; | |
1559 | ||
1560 | err: | |
1561 | drbg_dealloc_state(drbg); | |
1562 | return ret; | |
1563 | } | |
1564 | ||
1565 | /* | |
1566 | * DRBG uninstantiate function as required by SP800-90A - this function | |
1567 | * frees all buffers and the DRBG handle | |
1568 | * | |
1569 | * @drbg DRBG state handle | |
1570 | * | |
1571 | * return | |
1572 | * 0 on success | |
1573 | */ | |
1574 | static int drbg_uninstantiate(struct drbg_state *drbg) | |
1575 | { | |
1576 | spin_lock_bh(&drbg->drbg_lock); | |
1577 | drbg_dealloc_state(drbg); | |
1578 | /* no scrubbing of test_data -- this shall survive an uninstantiate */ | |
1579 | spin_unlock_bh(&drbg->drbg_lock); | |
1580 | return 0; | |
1581 | } | |
1582 | ||
1583 | /* | |
1584 | * Helper function for setting the test data in the DRBG | |
1585 | * | |
1586 | * @drbg DRBG state handle | |
1587 | * @test_data test data to sets | |
1588 | */ | |
1589 | static inline void drbg_set_testdata(struct drbg_state *drbg, | |
1590 | struct drbg_test_data *test_data) | |
1591 | { | |
1592 | if (!test_data || !test_data->testentropy) | |
1593 | return; | |
1594 | spin_lock_bh(&drbg->drbg_lock); | |
1595 | drbg->test_data = test_data; | |
1596 | spin_unlock_bh(&drbg->drbg_lock); | |
1597 | } | |
1598 | ||
1599 | /*************************************************************** | |
1600 | * Kernel crypto API cipher invocations requested by DRBG | |
1601 | ***************************************************************/ | |
1602 | ||
1603 | #if defined(CONFIG_CRYPTO_DRBG_HASH) || defined(CONFIG_CRYPTO_DRBG_HMAC) | |
1604 | struct sdesc { | |
1605 | struct shash_desc shash; | |
1606 | char ctx[]; | |
1607 | }; | |
1608 | ||
1609 | static int drbg_init_hash_kernel(struct drbg_state *drbg) | |
1610 | { | |
1611 | struct sdesc *sdesc; | |
1612 | struct crypto_shash *tfm; | |
1613 | ||
1614 | tfm = crypto_alloc_shash(drbg->core->backend_cra_name, 0, 0); | |
1615 | if (IS_ERR(tfm)) { | |
1616 | pr_info("DRBG: could not allocate digest TFM handle\n"); | |
1617 | return PTR_ERR(tfm); | |
1618 | } | |
1619 | BUG_ON(drbg_blocklen(drbg) != crypto_shash_digestsize(tfm)); | |
1620 | sdesc = kzalloc(sizeof(struct shash_desc) + crypto_shash_descsize(tfm), | |
1621 | GFP_KERNEL); | |
1622 | if (!sdesc) { | |
1623 | crypto_free_shash(tfm); | |
1624 | return -ENOMEM; | |
1625 | } | |
1626 | ||
1627 | sdesc->shash.tfm = tfm; | |
1628 | sdesc->shash.flags = 0; | |
1629 | drbg->priv_data = sdesc; | |
1630 | return 0; | |
1631 | } | |
1632 | ||
1633 | static int drbg_fini_hash_kernel(struct drbg_state *drbg) | |
1634 | { | |
1635 | struct sdesc *sdesc = (struct sdesc *)drbg->priv_data; | |
1636 | if (sdesc) { | |
1637 | crypto_free_shash(sdesc->shash.tfm); | |
1638 | kzfree(sdesc); | |
1639 | } | |
1640 | drbg->priv_data = NULL; | |
1641 | return 0; | |
1642 | } | |
1643 | ||
1644 | static int drbg_kcapi_hash(struct drbg_state *drbg, const unsigned char *key, | |
1645 | unsigned char *outval, const struct drbg_string *in) | |
1646 | { | |
1647 | struct sdesc *sdesc = (struct sdesc *)drbg->priv_data; | |
1648 | ||
1649 | if (key) | |
1650 | crypto_shash_setkey(sdesc->shash.tfm, key, drbg_statelen(drbg)); | |
1651 | crypto_shash_init(&sdesc->shash); | |
1652 | for (; NULL != in; in = in->next) | |
1653 | crypto_shash_update(&sdesc->shash, in->buf, in->len); | |
1654 | return crypto_shash_final(&sdesc->shash, outval); | |
1655 | } | |
1656 | #endif /* (CONFIG_CRYPTO_DRBG_HASH || CONFIG_CRYPTO_DRBG_HMAC) */ | |
1657 | ||
1658 | #ifdef CONFIG_CRYPTO_DRBG_CTR | |
1659 | static int drbg_init_sym_kernel(struct drbg_state *drbg) | |
1660 | { | |
1661 | int ret = 0; | |
1662 | struct crypto_blkcipher *tfm; | |
1663 | ||
1664 | tfm = crypto_alloc_blkcipher(drbg->core->backend_cra_name, 0, 0); | |
1665 | if (IS_ERR(tfm)) { | |
1666 | pr_info("DRBG: could not allocate cipher TFM handle\n"); | |
1667 | return PTR_ERR(tfm); | |
1668 | } | |
1669 | BUG_ON(drbg_blocklen(drbg) != crypto_blkcipher_blocksize(tfm)); | |
1670 | drbg->priv_data = tfm; | |
1671 | return ret; | |
1672 | } | |
1673 | ||
1674 | static int drbg_fini_sym_kernel(struct drbg_state *drbg) | |
1675 | { | |
1676 | struct crypto_blkcipher *tfm = | |
1677 | (struct crypto_blkcipher *)drbg->priv_data; | |
1678 | if (tfm) | |
1679 | crypto_free_blkcipher(tfm); | |
1680 | drbg->priv_data = NULL; | |
1681 | return 0; | |
1682 | } | |
1683 | ||
1684 | static int drbg_kcapi_sym(struct drbg_state *drbg, const unsigned char *key, | |
1685 | unsigned char *outval, const struct drbg_string *in) | |
1686 | { | |
1687 | int ret = 0; | |
1688 | struct scatterlist sg_in, sg_out; | |
1689 | struct blkcipher_desc desc; | |
1690 | struct crypto_blkcipher *tfm = | |
1691 | (struct crypto_blkcipher *)drbg->priv_data; | |
1692 | ||
1693 | desc.tfm = tfm; | |
1694 | desc.flags = 0; | |
1695 | crypto_blkcipher_setkey(tfm, key, (drbg_keylen(drbg))); | |
1696 | /* there is only component in *in */ | |
1697 | sg_init_one(&sg_in, in->buf, in->len); | |
1698 | sg_init_one(&sg_out, outval, drbg_blocklen(drbg)); | |
1699 | ret = crypto_blkcipher_encrypt(&desc, &sg_out, &sg_in, in->len); | |
1700 | ||
1701 | return ret; | |
1702 | } | |
1703 | #endif /* CONFIG_CRYPTO_DRBG_CTR */ | |
1704 | ||
1705 | /*************************************************************** | |
1706 | * Kernel crypto API interface to register DRBG | |
1707 | ***************************************************************/ | |
1708 | ||
1709 | /* | |
1710 | * Look up the DRBG flags by given kernel crypto API cra_name | |
1711 | * The code uses the drbg_cores definition to do this | |
1712 | * | |
1713 | * @cra_name kernel crypto API cra_name | |
1714 | * @coreref reference to integer which is filled with the pointer to | |
1715 | * the applicable core | |
1716 | * @pr reference for setting prediction resistance | |
1717 | * | |
1718 | * return: flags | |
1719 | */ | |
1720 | static inline void drbg_convert_tfm_core(const char *cra_driver_name, | |
1721 | int *coreref, bool *pr) | |
1722 | { | |
1723 | int i = 0; | |
1724 | size_t start = 0; | |
1725 | int len = 0; | |
1726 | ||
1727 | *pr = true; | |
1728 | /* disassemble the names */ | |
1729 | if (!memcmp(cra_driver_name, "drbg_nopr_", 10)) { | |
1730 | start = 10; | |
1731 | *pr = false; | |
1732 | } else if (!memcmp(cra_driver_name, "drbg_pr_", 8)) { | |
1733 | start = 8; | |
1734 | } else { | |
1735 | return; | |
1736 | } | |
1737 | ||
1738 | /* remove the first part */ | |
1739 | len = strlen(cra_driver_name) - start; | |
1740 | for (i = 0; ARRAY_SIZE(drbg_cores) > i; i++) { | |
1741 | if (!memcmp(cra_driver_name + start, drbg_cores[i].cra_name, | |
1742 | len)) { | |
1743 | *coreref = i; | |
1744 | return; | |
1745 | } | |
1746 | } | |
1747 | } | |
1748 | ||
1749 | static int drbg_kcapi_init(struct crypto_tfm *tfm) | |
1750 | { | |
1751 | struct drbg_state *drbg = crypto_tfm_ctx(tfm); | |
1752 | bool pr = false; | |
1753 | int coreref = 0; | |
1754 | ||
1755 | drbg_convert_tfm_core(crypto_tfm_alg_name(tfm), &coreref, &pr); | |
1756 | /* | |
1757 | * when personalization string is needed, the caller must call reset | |
1758 | * and provide the personalization string as seed information | |
1759 | */ | |
1760 | return drbg_instantiate(drbg, NULL, coreref, pr); | |
1761 | } | |
1762 | ||
1763 | static void drbg_kcapi_cleanup(struct crypto_tfm *tfm) | |
1764 | { | |
1765 | drbg_uninstantiate(crypto_tfm_ctx(tfm)); | |
1766 | } | |
1767 | ||
1768 | /* | |
1769 | * Generate random numbers invoked by the kernel crypto API: | |
1770 | * The API of the kernel crypto API is extended as follows: | |
1771 | * | |
1772 | * If dlen is larger than zero, rdata is interpreted as the output buffer | |
1773 | * where random data is to be stored. | |
1774 | * | |
1775 | * If dlen is zero, rdata is interpreted as a pointer to a struct drbg_gen | |
1776 | * which holds the additional information string that is used for the | |
1777 | * DRBG generation process. The output buffer that is to be used to store | |
1778 | * data is also pointed to by struct drbg_gen. | |
1779 | */ | |
1780 | static int drbg_kcapi_random(struct crypto_rng *tfm, u8 *rdata, | |
1781 | unsigned int dlen) | |
1782 | { | |
1783 | struct drbg_state *drbg = crypto_rng_ctx(tfm); | |
1784 | if (0 < dlen) { | |
1785 | return drbg_generate_long(drbg, rdata, dlen, NULL); | |
1786 | } else { | |
1787 | struct drbg_gen *data = (struct drbg_gen *)rdata; | |
1788 | /* catch NULL pointer */ | |
1789 | if (!data) | |
1790 | return 0; | |
1791 | drbg_set_testdata(drbg, data->test_data); | |
1792 | return drbg_generate_long(drbg, data->outbuf, data->outlen, | |
1793 | data->addtl); | |
1794 | } | |
1795 | } | |
1796 | ||
1797 | /* | |
1798 | * Reset the DRBG invoked by the kernel crypto API | |
1799 | * The reset implies a full re-initialization of the DRBG. Similar to the | |
1800 | * generate function of drbg_kcapi_random, this function extends the | |
1801 | * kernel crypto API interface with struct drbg_gen | |
1802 | */ | |
1803 | static int drbg_kcapi_reset(struct crypto_rng *tfm, u8 *seed, unsigned int slen) | |
1804 | { | |
1805 | struct drbg_state *drbg = crypto_rng_ctx(tfm); | |
1806 | struct crypto_tfm *tfm_base = crypto_rng_tfm(tfm); | |
1807 | bool pr = false; | |
1808 | struct drbg_string seed_string; | |
1809 | int coreref = 0; | |
1810 | ||
1811 | drbg_uninstantiate(drbg); | |
1812 | drbg_convert_tfm_core(crypto_tfm_alg_driver_name(tfm_base), &coreref, | |
1813 | &pr); | |
1814 | if (0 < slen) { | |
1815 | drbg_string_fill(&seed_string, seed, slen); | |
1816 | return drbg_instantiate(drbg, &seed_string, coreref, pr); | |
1817 | } else { | |
1818 | struct drbg_gen *data = (struct drbg_gen *)seed; | |
1819 | /* allow invocation of API call with NULL, 0 */ | |
1820 | if (!data) | |
1821 | return drbg_instantiate(drbg, NULL, coreref, pr); | |
1822 | drbg_set_testdata(drbg, data->test_data); | |
1823 | return drbg_instantiate(drbg, data->addtl, coreref, pr); | |
1824 | } | |
1825 | } | |
1826 | ||
1827 | /*************************************************************** | |
1828 | * Kernel module: code to load the module | |
1829 | ***************************************************************/ | |
1830 | ||
1831 | /* | |
1832 | * Tests as defined in 11.3.2 in addition to the cipher tests: testing | |
1833 | * of the error handling. | |
1834 | * | |
1835 | * Note: testing of failing seed source as defined in 11.3.2 is not applicable | |
1836 | * as seed source of get_random_bytes does not fail. | |
1837 | * | |
1838 | * Note 2: There is no sensible way of testing the reseed counter | |
1839 | * enforcement, so skip it. | |
1840 | */ | |
1841 | static inline int __init drbg_healthcheck_sanity(void) | |
1842 | { | |
1843 | #ifdef CONFIG_CRYPTO_FIPS | |
1844 | int len = 0; | |
1845 | #define OUTBUFLEN 16 | |
1846 | unsigned char buf[OUTBUFLEN]; | |
1847 | struct drbg_state *drbg = NULL; | |
1848 | int ret = -EFAULT; | |
1849 | int rc = -EFAULT; | |
1850 | bool pr = false; | |
1851 | int coreref = 0; | |
1852 | struct drbg_string addtl; | |
1853 | size_t max_addtllen, max_request_bytes; | |
1854 | ||
1855 | /* only perform test in FIPS mode */ | |
1856 | if (!fips_enabled) | |
1857 | return 0; | |
1858 | ||
1859 | #ifdef CONFIG_CRYPTO_DRBG_CTR | |
1860 | drbg_convert_tfm_core("drbg_nopr_ctr_aes128", &coreref, &pr); | |
1861 | #elif CONFIG_CRYPTO_DRBG_HASH | |
1862 | drbg_convert_tfm_core("drbg_nopr_sha256", &coreref, &pr); | |
1863 | #else | |
1864 | drbg_convert_tfm_core("drbg_nopr_hmac_sha256", &coreref, &pr); | |
1865 | #endif | |
1866 | ||
1867 | drbg = kzalloc(sizeof(struct drbg_state), GFP_KERNEL); | |
1868 | if (!drbg) | |
1869 | return -ENOMEM; | |
1870 | ||
1871 | /* | |
1872 | * if the following tests fail, it is likely that there is a buffer | |
1873 | * overflow as buf is much smaller than the requested or provided | |
1874 | * string lengths -- in case the error handling does not succeed | |
1875 | * we may get an OOPS. And we want to get an OOPS as this is a | |
1876 | * grave bug. | |
1877 | */ | |
1878 | ||
1879 | /* get a valid instance of DRBG for following tests */ | |
1880 | ret = drbg_instantiate(drbg, NULL, coreref, pr); | |
1881 | if (ret) { | |
1882 | rc = ret; | |
1883 | goto outbuf; | |
1884 | } | |
1885 | max_addtllen = drbg_max_addtl(drbg); | |
1886 | max_request_bytes = drbg_max_request_bytes(drbg); | |
1887 | drbg_string_fill(&addtl, buf, max_addtllen + 1); | |
1888 | /* overflow addtllen with additonal info string */ | |
1889 | len = drbg_generate(drbg, buf, OUTBUFLEN, &addtl); | |
1890 | BUG_ON(0 < len); | |
1891 | /* overflow max_bits */ | |
1892 | len = drbg_generate(drbg, buf, (max_request_bytes + 1), NULL); | |
1893 | BUG_ON(0 < len); | |
1894 | drbg_uninstantiate(drbg); | |
1895 | ||
1896 | /* overflow max addtllen with personalization string */ | |
1897 | ret = drbg_instantiate(drbg, &addtl, coreref, pr); | |
1898 | BUG_ON(0 == ret); | |
1899 | /* test uninstantated DRBG */ | |
1900 | len = drbg_generate(drbg, buf, (max_request_bytes + 1), NULL); | |
1901 | BUG_ON(0 < len); | |
1902 | /* all tests passed */ | |
1903 | rc = 0; | |
1904 | ||
1905 | pr_devel("DRBG: Sanity tests for failure code paths successfully " | |
1906 | "completed\n"); | |
1907 | ||
1908 | drbg_uninstantiate(drbg); | |
1909 | outbuf: | |
1910 | kzfree(drbg); | |
1911 | return rc; | |
1912 | #else /* CONFIG_CRYPTO_FIPS */ | |
1913 | return 0; | |
1914 | #endif /* CONFIG_CRYPTO_FIPS */ | |
1915 | } | |
1916 | ||
1917 | static struct crypto_alg drbg_algs[22]; | |
1918 | ||
1919 | /* | |
1920 | * Fill the array drbg_algs used to register the different DRBGs | |
1921 | * with the kernel crypto API. To fill the array, the information | |
1922 | * from drbg_cores[] is used. | |
1923 | */ | |
1924 | static inline void __init drbg_fill_array(struct crypto_alg *alg, | |
1925 | const struct drbg_core *core, int pr) | |
1926 | { | |
1927 | int pos = 0; | |
1928 | static int priority = 100; | |
1929 | ||
1930 | memset(alg, 0, sizeof(struct crypto_alg)); | |
1931 | memcpy(alg->cra_name, "stdrng", 6); | |
1932 | if (pr) { | |
1933 | memcpy(alg->cra_driver_name, "drbg_pr_", 8); | |
1934 | pos = 8; | |
1935 | } else { | |
1936 | memcpy(alg->cra_driver_name, "drbg_nopr_", 10); | |
1937 | pos = 10; | |
1938 | } | |
1939 | memcpy(alg->cra_driver_name + pos, core->cra_name, | |
1940 | strlen(core->cra_name)); | |
1941 | ||
1942 | alg->cra_priority = priority; | |
1943 | priority++; | |
1944 | /* | |
1945 | * If FIPS mode enabled, the selected DRBG shall have the | |
1946 | * highest cra_priority over other stdrng instances to ensure | |
1947 | * it is selected. | |
1948 | */ | |
1949 | if (fips_enabled) | |
1950 | alg->cra_priority += 200; | |
1951 | ||
1952 | alg->cra_flags = CRYPTO_ALG_TYPE_RNG; | |
1953 | alg->cra_ctxsize = sizeof(struct drbg_state); | |
1954 | alg->cra_type = &crypto_rng_type; | |
1955 | alg->cra_module = THIS_MODULE; | |
1956 | alg->cra_init = drbg_kcapi_init; | |
1957 | alg->cra_exit = drbg_kcapi_cleanup; | |
1958 | alg->cra_u.rng.rng_make_random = drbg_kcapi_random; | |
1959 | alg->cra_u.rng.rng_reset = drbg_kcapi_reset; | |
1960 | alg->cra_u.rng.seedsize = 0; | |
1961 | } | |
1962 | ||
1963 | static int __init drbg_init(void) | |
1964 | { | |
1965 | unsigned int i = 0; /* pointer to drbg_algs */ | |
1966 | unsigned int j = 0; /* pointer to drbg_cores */ | |
1967 | int ret = -EFAULT; | |
1968 | ||
1969 | ret = drbg_healthcheck_sanity(); | |
1970 | if (ret) | |
1971 | return ret; | |
1972 | ||
1973 | if (ARRAY_SIZE(drbg_cores) * 2 > ARRAY_SIZE(drbg_algs)) { | |
1974 | pr_info("DRBG: Cannot register all DRBG types" | |
1975 | "(slots needed: %lu, slots available: %lu)\n", | |
1976 | ARRAY_SIZE(drbg_cores) * 2, ARRAY_SIZE(drbg_algs)); | |
1977 | return ret; | |
1978 | } | |
1979 | ||
1980 | /* | |
1981 | * each DRBG definition can be used with PR and without PR, thus | |
1982 | * we instantiate each DRBG in drbg_cores[] twice. | |
1983 | * | |
1984 | * As the order of placing them into the drbg_algs array matters | |
1985 | * (the later DRBGs receive a higher cra_priority) we register the | |
1986 | * prediction resistance DRBGs first as the should not be too | |
1987 | * interesting. | |
1988 | */ | |
1989 | for (j = 0; ARRAY_SIZE(drbg_cores) > j; j++, i++) | |
1990 | drbg_fill_array(&drbg_algs[i], &drbg_cores[j], 1); | |
1991 | for (j = 0; ARRAY_SIZE(drbg_cores) > j; j++, i++) | |
1992 | drbg_fill_array(&drbg_algs[i], &drbg_cores[j], 0); | |
1993 | return crypto_register_algs(drbg_algs, (ARRAY_SIZE(drbg_cores) * 2)); | |
1994 | } | |
1995 | ||
1996 | void __exit drbg_exit(void) | |
1997 | { | |
1998 | crypto_unregister_algs(drbg_algs, (ARRAY_SIZE(drbg_cores) * 2)); | |
1999 | } | |
2000 | ||
2001 | module_init(drbg_init); | |
2002 | module_exit(drbg_exit); | |
2003 | MODULE_LICENSE("GPL"); | |
2004 | MODULE_AUTHOR("Stephan Mueller <smueller@chronox.de>"); | |
2005 | MODULE_DESCRIPTION("NIST SP800-90A Deterministic Random Bit Generator (DRBG) using following cores:" | |
2006 | #ifdef CONFIG_CRYPTO_DRBG_HMAC | |
2007 | "HMAC " | |
2008 | #endif | |
2009 | #ifdef CONFIG_CRYPTO_DRBG_HASH | |
2010 | "Hash " | |
2011 | #endif | |
2012 | #ifdef CONFIG_CRYPTO_DRBG_CTR | |
2013 | "CTR" | |
2014 | #endif | |
2015 | ); |