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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
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 */
121static 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 */
244static 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 */
280static 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))
316static 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 */
333static 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
365static int drbg_kcapi_sym(struct drbg_state *drbg, const unsigned char *key,
366 unsigned char *outval, const struct drbg_string *in);
367static int drbg_init_sym_kernel(struct drbg_state *drbg);
368static int drbg_fini_sym_kernel(struct drbg_state *drbg);
369
370/* BCC function for CTR DRBG as defined in 10.4.3 */
371static 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)
449 * length: (drbg_keylen(drbg) + drbg_blocklen(drbg) ==
450 * drbg_statelen(drbg))
451 */
452
453/* Derivation Function for CTR DRBG as defined in 10.4.2 */
454static int drbg_ctr_df(struct drbg_state *drbg,
455 unsigned char *df_data, size_t bytes_to_return,
456 struct drbg_string *addtl)
457{
458 int ret = -EFAULT;
459 unsigned char L_N[8];
460 /* S3 is input */
461 struct drbg_string S1, S2, S4, cipherin;
462 struct drbg_string *tempstr = addtl;
463 unsigned char *pad = df_data + drbg_statelen(drbg);
464 unsigned char *iv = pad + drbg_blocklen(drbg);
465 unsigned char *temp = iv + drbg_blocklen(drbg);
466 size_t padlen = 0;
467 unsigned int templen = 0;
468 /* 10.4.2 step 7 */
469 unsigned int i = 0;
470 /* 10.4.2 step 8 */
471 const unsigned char *K = (unsigned char *)
472 "\x00\x01\x02\x03\x04\x05\x06\x07"
473 "\x08\x09\x0a\x0b\x0c\x0d\x0e\x0f"
474 "\x10\x11\x12\x13\x14\x15\x16\x17"
475 "\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f";
476 unsigned char *X;
477 size_t generated_len = 0;
478 size_t inputlen = 0;
479
480 memset(pad, 0, drbg_blocklen(drbg));
481 memset(iv, 0, drbg_blocklen(drbg));
482 memset(temp, 0, drbg_statelen(drbg));
483
484 /* 10.4.2 step 1 is implicit as we work byte-wise */
485
486 /* 10.4.2 step 2 */
487 if ((512/8) < bytes_to_return)
488 return -EINVAL;
489
490 /* 10.4.2 step 2 -- calculate the entire length of all input data */
491 for (; NULL != tempstr; tempstr = tempstr->next)
492 inputlen += tempstr->len;
493 drbg_int2byte(&L_N[0], inputlen, 4);
494
495 /* 10.4.2 step 3 */
496 drbg_int2byte(&L_N[4], bytes_to_return, 4);
497
498 /* 10.4.2 step 5: length is L_N, input_string, one byte, padding */
499 padlen = (inputlen + sizeof(L_N) + 1) % (drbg_blocklen(drbg));
500 /* wrap the padlen appropriately */
501 if (padlen)
502 padlen = drbg_blocklen(drbg) - padlen;
503 /*
504 * pad / padlen contains the 0x80 byte and the following zero bytes.
505 * As the calculated padlen value only covers the number of zero
506 * bytes, this value has to be incremented by one for the 0x80 byte.
507 */
508 padlen++;
509 pad[0] = 0x80;
510
511 /* 10.4.2 step 4 -- first fill the linked list and then order it */
512 drbg_string_fill(&S1, iv, drbg_blocklen(drbg));
513 drbg_string_fill(&S2, L_N, sizeof(L_N));
514 drbg_string_fill(&S4, pad, padlen);
515 S1.next = &S2;
516 S2.next = addtl;
517
518 /*
519 * splice in addtl between S2 and S4 -- we place S4 at the end of the
520 * input data chain
521 */
522 tempstr = addtl;
523 for (; NULL != tempstr; tempstr = tempstr->next)
524 if (NULL == tempstr->next)
525 break;
526 tempstr->next = &S4;
527
528 /* 10.4.2 step 9 */
529 while (templen < (drbg_keylen(drbg) + (drbg_blocklen(drbg)))) {
530 /*
531 * 10.4.2 step 9.1 - the padding is implicit as the buffer
532 * holds zeros after allocation -- even the increment of i
533 * is irrelevant as the increment remains within length of i
534 */
535 drbg_int2byte(iv, i, 4);
536 /* 10.4.2 step 9.2 -- BCC and concatenation with temp */
537 ret = drbg_ctr_bcc(drbg, temp + templen, K, &S1);
538 if (ret)
539 goto out;
540 /* 10.4.2 step 9.3 */
541 i++;
542 templen += drbg_blocklen(drbg);
543 }
544
545 /* 10.4.2 step 11 */
546 X = temp + (drbg_keylen(drbg));
547 drbg_string_fill(&cipherin, X, drbg_blocklen(drbg));
548
549 /* 10.4.2 step 12: overwriting of outval is implemented in next step */
550
551 /* 10.4.2 step 13 */
552 while (generated_len < bytes_to_return) {
553 short blocklen = 0;
554 /*
555 * 10.4.2 step 13.1: the truncation of the key length is
556 * implicit as the key is only drbg_blocklen in size based on
557 * the implementation of the cipher function callback
558 */
559 ret = drbg_kcapi_sym(drbg, temp, X, &cipherin);
560 if (ret)
561 goto out;
562 blocklen = (drbg_blocklen(drbg) <
563 (bytes_to_return - generated_len)) ?
564 drbg_blocklen(drbg) :
565 (bytes_to_return - generated_len);
566 /* 10.4.2 step 13.2 and 14 */
567 memcpy(df_data + generated_len, X, blocklen);
568 generated_len += blocklen;
569 }
570
571 ret = 0;
572
573out:
574 memset(iv, 0, drbg_blocklen(drbg));
575 memset(temp, 0, drbg_statelen(drbg));
576 memset(pad, 0, drbg_blocklen(drbg));
577 return ret;
578}
579
580/* update function of CTR DRBG as defined in 10.2.1.2 */
581static int drbg_ctr_update(struct drbg_state *drbg,
582 struct drbg_string *addtl, int reseed)
583{
584 int ret = -EFAULT;
585 /* 10.2.1.2 step 1 */
586 unsigned char *temp = drbg->scratchpad;
587 unsigned char *df_data = drbg->scratchpad + drbg_statelen(drbg) +
588 drbg_blocklen(drbg);
589 unsigned char *temp_p, *df_data_p; /* pointer to iterate over buffers */
590 unsigned int len = 0;
591 struct drbg_string cipherin;
592 unsigned char prefix = DRBG_PREFIX1;
593
594 memset(temp, 0, drbg_statelen(drbg) + drbg_blocklen(drbg));
595 memset(df_data, 0, drbg_statelen(drbg));
596
597 /* 10.2.1.3.2 step 2 and 10.2.1.4.2 step 2 */
598 if (addtl && 0 < addtl->len) {
599 ret = drbg_ctr_df(drbg, df_data, drbg_statelen(drbg),
600 addtl);
601 if (ret)
602 goto out;
603 }
604
605 drbg_string_fill(&cipherin, drbg->V, drbg_blocklen(drbg));
606 /*
607 * 10.2.1.3.2 steps 2 and 3 are already covered as the allocation
608 * zeroizes all memory during initialization
609 */
610 while (len < (drbg_statelen(drbg))) {
611 /* 10.2.1.2 step 2.1 */
612 drbg_add_buf(drbg->V, drbg_blocklen(drbg), &prefix, 1);
613 /*
614 * 10.2.1.2 step 2.2 */
615 ret = drbg_kcapi_sym(drbg, drbg->C, temp + len, &cipherin);
616 if (ret)
617 goto out;
618 /* 10.2.1.2 step 2.3 and 3 */
619 len += drbg_blocklen(drbg);
620 }
621
622 /* 10.2.1.2 step 4 */
623 temp_p = temp;
624 df_data_p = df_data;
625 for (len = 0; len < drbg_statelen(drbg); len++) {
626 *temp_p ^= *df_data_p;
627 df_data_p++; temp_p++;
628 }
629
630 /* 10.2.1.2 step 5 */
631 memcpy(drbg->C, temp, drbg_keylen(drbg));
632 /* 10.2.1.2 step 6 */
633 memcpy(drbg->V, temp + drbg_keylen(drbg), drbg_blocklen(drbg));
634 ret = 0;
635
636out:
637 memset(temp, 0, drbg_statelen(drbg) + drbg_blocklen(drbg));
638 memset(df_data, 0, drbg_statelen(drbg));
639 return ret;
640}
641
642/*
643 * scratchpad use: drbg_ctr_update is called independently from
644 * drbg_ctr_extract_bytes. Therefore, the scratchpad is reused
645 */
646/* Generate function of CTR DRBG as defined in 10.2.1.5.2 */
647static int drbg_ctr_generate(struct drbg_state *drbg,
648 unsigned char *buf, unsigned int buflen,
649 struct drbg_string *addtl)
650{
651 int len = 0;
652 int ret = 0;
653 struct drbg_string data;
654 unsigned char prefix = DRBG_PREFIX1;
655
656 memset(drbg->scratchpad, 0, drbg_blocklen(drbg));
657
658 /* 10.2.1.5.2 step 2 */
659 if (addtl && 0 < addtl->len) {
660 addtl->next = NULL;
661 ret = drbg_ctr_update(drbg, addtl, 1);
662 if (ret)
663 return 0;
664 }
665
666 /* 10.2.1.5.2 step 4.1 */
667 drbg_add_buf(drbg->V, drbg_blocklen(drbg), &prefix, 1);
668 drbg_string_fill(&data, drbg->V, drbg_blocklen(drbg));
669 while (len < buflen) {
670 int outlen = 0;
671 /* 10.2.1.5.2 step 4.2 */
672 ret = drbg_kcapi_sym(drbg, drbg->C, drbg->scratchpad, &data);
673 if (ret) {
674 len = ret;
675 goto out;
676 }
677 outlen = (drbg_blocklen(drbg) < (buflen - len)) ?
678 drbg_blocklen(drbg) : (buflen - len);
679 if (!drbg_fips_continuous_test(drbg, drbg->scratchpad)) {
680 /* 10.2.1.5.2 step 6 */
681 drbg_add_buf(drbg->V, drbg_blocklen(drbg), &prefix, 1);
682 continue;
683 }
684 /* 10.2.1.5.2 step 4.3 */
685 memcpy(buf + len, drbg->scratchpad, outlen);
686 len += outlen;
687 /* 10.2.1.5.2 step 6 */
688 if (len < buflen)
689 drbg_add_buf(drbg->V, drbg_blocklen(drbg), &prefix, 1);
690 }
691
692 /* 10.2.1.5.2 step 6 */
693 if (addtl)
694 addtl->next = NULL;
695 /*
696 * The following call invokes the DF function again which could be
697 * optimized. In step 2, the "additional_input" after step 2 is the
698 * output of the DF function. If this result would be saved, the DF
699 * function would not need to be invoked again at this point.
700 */
701 ret = drbg_ctr_update(drbg, addtl, 1);
702 if (ret)
703 len = ret;
704
705out:
706 memset(drbg->scratchpad, 0, drbg_blocklen(drbg));
707 return len;
708}
709
710static struct drbg_state_ops drbg_ctr_ops = {
711 .update = drbg_ctr_update,
712 .generate = drbg_ctr_generate,
713 .crypto_init = drbg_init_sym_kernel,
714 .crypto_fini = drbg_fini_sym_kernel,
715};
716#endif /* CONFIG_CRYPTO_DRBG_CTR */
717
718/******************************************************************
719 * HMAC DRBG callback functions
720 ******************************************************************/
721
722#if defined(CONFIG_CRYPTO_DRBG_HASH) || defined(CONFIG_CRYPTO_DRBG_HMAC)
723static int drbg_kcapi_hash(struct drbg_state *drbg, const unsigned char *key,
724 unsigned char *outval, const struct drbg_string *in);
725static int drbg_init_hash_kernel(struct drbg_state *drbg);
726static int drbg_fini_hash_kernel(struct drbg_state *drbg);
727#endif /* (CONFIG_CRYPTO_DRBG_HASH || CONFIG_CRYPTO_DRBG_HMAC) */
728
729#ifdef CONFIG_CRYPTO_DRBG_HMAC
730/* update function of HMAC DRBG as defined in 10.1.2.2 */
731static int drbg_hmac_update(struct drbg_state *drbg,
732 struct drbg_string *seed, int reseed)
733{
734 int ret = -EFAULT;
735 int i = 0;
736 struct drbg_string seed1, seed2, cipherin;
737
738 if (!reseed) {
739 /* 10.1.2.3 step 2 */
740 memset(drbg->C, 0, drbg_statelen(drbg));
741 memset(drbg->V, 1, drbg_statelen(drbg));
742 }
743
744 drbg_string_fill(&seed1, drbg->V, drbg_statelen(drbg));
745 /* buffer of seed2 will be filled in for loop below with one byte */
746 drbg_string_fill(&seed2, NULL, 1);
747 seed1.next = &seed2;
748 /* input data of seed is allowed to be NULL at this point */
749 seed2.next = seed;
750
751 drbg_string_fill(&cipherin, drbg->V, drbg_statelen(drbg));
752 for (i = 2; 0 < i; i--) {
753 /* first round uses 0x0, second 0x1 */
754 unsigned char prefix = DRBG_PREFIX0;
755 if (1 == i)
756 prefix = DRBG_PREFIX1;
757 /* 10.1.2.2 step 1 and 4 -- concatenation and HMAC for key */
758 seed2.buf = &prefix;
759 ret = drbg_kcapi_hash(drbg, drbg->C, drbg->C, &seed1);
760 if (ret)
761 return ret;
762
763 /* 10.1.2.2 step 2 and 5 -- HMAC for V */
764 ret = drbg_kcapi_hash(drbg, drbg->C, drbg->V, &cipherin);
765 if (ret)
766 return ret;
767
768 /* 10.1.2.2 step 3 */
769 if (!seed || 0 == seed->len)
770 return ret;
771 }
772
773 return 0;
774}
775
776/* generate function of HMAC DRBG as defined in 10.1.2.5 */
777static int drbg_hmac_generate(struct drbg_state *drbg,
778 unsigned char *buf,
779 unsigned int buflen,
780 struct drbg_string *addtl)
781{
782 int len = 0;
783 int ret = 0;
784 struct drbg_string data;
785
786 /* 10.1.2.5 step 2 */
787 if (addtl && 0 < addtl->len) {
788 addtl->next = NULL;
789 ret = drbg_hmac_update(drbg, addtl, 1);
790 if (ret)
791 return ret;
792 }
793
794 drbg_string_fill(&data, drbg->V, drbg_statelen(drbg));
795 while (len < buflen) {
796 unsigned int outlen = 0;
797 /* 10.1.2.5 step 4.1 */
798 ret = drbg_kcapi_hash(drbg, drbg->C, drbg->V, &data);
799 if (ret)
800 return ret;
801 outlen = (drbg_blocklen(drbg) < (buflen - len)) ?
802 drbg_blocklen(drbg) : (buflen - len);
803 if (!drbg_fips_continuous_test(drbg, drbg->V))
804 continue;
805
806 /* 10.1.2.5 step 4.2 */
807 memcpy(buf + len, drbg->V, outlen);
808 len += outlen;
809 }
810
811 /* 10.1.2.5 step 6 */
812 if (addtl)
813 addtl->next = NULL;
814 ret = drbg_hmac_update(drbg, addtl, 1);
815 if (ret)
816 return ret;
817
818 return len;
819}
820
821static struct drbg_state_ops drbg_hmac_ops = {
822 .update = drbg_hmac_update,
823 .generate = drbg_hmac_generate,
824 .crypto_init = drbg_init_hash_kernel,
825 .crypto_fini = drbg_fini_hash_kernel,
826
827};
828#endif /* CONFIG_CRYPTO_DRBG_HMAC */
829
830/******************************************************************
831 * Hash DRBG callback functions
832 ******************************************************************/
833
834#ifdef CONFIG_CRYPTO_DRBG_HASH
835/*
836 * scratchpad usage: as drbg_hash_update and drbg_hash_df are used
837 * interlinked, the scratchpad is used as follows:
838 * drbg_hash_update
839 * start: drbg->scratchpad
840 * length: drbg_statelen(drbg)
841 * drbg_hash_df:
842 * start: drbg->scratchpad + drbg_statelen(drbg)
843 * length: drbg_blocklen(drbg)
844 *
845 * drbg_hash_process_addtl uses the scratchpad, but fully completes
846 * before either of the functions mentioned before are invoked. Therefore,
847 * drbg_hash_process_addtl does not need to be specifically considered.
848 */
849
850/* Derivation Function for Hash DRBG as defined in 10.4.1 */
851static int drbg_hash_df(struct drbg_state *drbg,
852 unsigned char *outval, size_t outlen,
853 struct drbg_string *entropy)
854{
855 int ret = 0;
856 size_t len = 0;
857 unsigned char input[5];
858 unsigned char *tmp = drbg->scratchpad + drbg_statelen(drbg);
859 struct drbg_string data1;
860
861 memset(tmp, 0, drbg_blocklen(drbg));
862
863 /* 10.4.1 step 3 */
864 input[0] = 1;
865 drbg_int2byte(&input[1], (outlen * 8), 4);
866
867 /* 10.4.1 step 4.1 -- concatenation of data for input into hash */
868 drbg_string_fill(&data1, input, 5);
869 data1.next = entropy;
870
871 /* 10.4.1 step 4 */
872 while (len < outlen) {
873 short blocklen = 0;
874 /* 10.4.1 step 4.1 */
875 ret = drbg_kcapi_hash(drbg, NULL, tmp, &data1);
876 if (ret)
877 goto out;
878 /* 10.4.1 step 4.2 */
879 input[0]++;
880 blocklen = (drbg_blocklen(drbg) < (outlen - len)) ?
881 drbg_blocklen(drbg) : (outlen - len);
882 memcpy(outval + len, tmp, blocklen);
883 len += blocklen;
884 }
885
886out:
887 memset(tmp, 0, drbg_blocklen(drbg));
888 return ret;
889}
890
891/* update function for Hash DRBG as defined in 10.1.1.2 / 10.1.1.3 */
892static int drbg_hash_update(struct drbg_state *drbg, struct drbg_string *seed,
893 int reseed)
894{
895 int ret = 0;
896 struct drbg_string data1, data2;
897 unsigned char *V = drbg->scratchpad;
898 unsigned char prefix = DRBG_PREFIX1;
899
900 memset(drbg->scratchpad, 0, drbg_statelen(drbg));
901 if (!seed)
902 return -EINVAL;
903
904 if (reseed) {
905 /* 10.1.1.3 step 1 */
906 memcpy(V, drbg->V, drbg_statelen(drbg));
907 drbg_string_fill(&data1, &prefix, 1);
908 drbg_string_fill(&data2, V, drbg_statelen(drbg));
909 data1.next = &data2;
910 data2.next = seed;
911 } else {
912 drbg_string_fill(&data1, seed->buf, seed->len);
913 data1.next = seed->next;
914 }
915
916 /* 10.1.1.2 / 10.1.1.3 step 2 and 3 */
917 ret = drbg_hash_df(drbg, drbg->V, drbg_statelen(drbg), &data1);
918 if (ret)
919 goto out;
920
921 /* 10.1.1.2 / 10.1.1.3 step 4 */
922 prefix = DRBG_PREFIX0;
923 drbg_string_fill(&data1, &prefix, 1);
924 drbg_string_fill(&data2, drbg->V, drbg_statelen(drbg));
925 data1.next = &data2;
926 /* 10.1.1.2 / 10.1.1.3 step 4 */
927 ret = drbg_hash_df(drbg, drbg->C, drbg_statelen(drbg), &data1);
928
929out:
930 memset(drbg->scratchpad, 0, drbg_statelen(drbg));
931 return ret;
932}
933
934/* processing of additional information string for Hash DRBG */
935static int drbg_hash_process_addtl(struct drbg_state *drbg,
936 struct drbg_string *addtl)
937{
938 int ret = 0;
939 struct drbg_string data1, data2;
940 struct drbg_string *data3;
941 unsigned char prefix = DRBG_PREFIX2;
942
943 /* this is value w as per documentation */
944 memset(drbg->scratchpad, 0, drbg_blocklen(drbg));
945
946 /* 10.1.1.4 step 2 */
947 if (!addtl || 0 == addtl->len)
948 return 0;
949
950 /* 10.1.1.4 step 2a */
951 drbg_string_fill(&data1, &prefix, 1);
952 drbg_string_fill(&data2, drbg->V, drbg_statelen(drbg));
953 data3 = addtl;
954 data1.next = &data2;
955 data2.next = data3;
956 data3->next = NULL;
957 ret = drbg_kcapi_hash(drbg, NULL, drbg->scratchpad, &data1);
958 if (ret)
959 goto out;
960
961 /* 10.1.1.4 step 2b */
962 drbg_add_buf(drbg->V, drbg_statelen(drbg),
963 drbg->scratchpad, drbg_blocklen(drbg));
964
965out:
966 memset(drbg->scratchpad, 0, drbg_blocklen(drbg));
967 return ret;
968}
969
970/* Hashgen defined in 10.1.1.4 */
971static int drbg_hash_hashgen(struct drbg_state *drbg,
972 unsigned char *buf,
973 unsigned int buflen)
974{
975 int len = 0;
976 int ret = 0;
977 unsigned char *src = drbg->scratchpad;
978 unsigned char *dst = drbg->scratchpad + drbg_statelen(drbg);
979 struct drbg_string data;
980 unsigned char prefix = DRBG_PREFIX1;
981
982 memset(src, 0, drbg_statelen(drbg));
983 memset(dst, 0, drbg_blocklen(drbg));
984
985 /* 10.1.1.4 step hashgen 2 */
986 memcpy(src, drbg->V, drbg_statelen(drbg));
987
988 drbg_string_fill(&data, src, drbg_statelen(drbg));
989 while (len < buflen) {
990 unsigned int outlen = 0;
991 /* 10.1.1.4 step hashgen 4.1 */
992 ret = drbg_kcapi_hash(drbg, NULL, dst, &data);
993 if (ret) {
994 len = ret;
995 goto out;
996 }
997 outlen = (drbg_blocklen(drbg) < (buflen - len)) ?
998 drbg_blocklen(drbg) : (buflen - len);
999 if (!drbg_fips_continuous_test(drbg, dst)) {
1000 drbg_add_buf(src, drbg_statelen(drbg), &prefix, 1);
1001 continue;
1002 }
1003 /* 10.1.1.4 step hashgen 4.2 */
1004 memcpy(buf + len, dst, outlen);
1005 len += outlen;
1006 /* 10.1.1.4 hashgen step 4.3 */
1007 if (len < buflen)
1008 drbg_add_buf(src, drbg_statelen(drbg), &prefix, 1);
1009 }
1010
1011out:
1012 memset(drbg->scratchpad, 0,
1013 (drbg_statelen(drbg) + drbg_blocklen(drbg)));
1014 return len;
1015}
1016
1017/* generate function for Hash DRBG as defined in 10.1.1.4 */
1018static int drbg_hash_generate(struct drbg_state *drbg,
1019 unsigned char *buf, unsigned int buflen,
1020 struct drbg_string *addtl)
1021{
1022 int len = 0;
1023 int ret = 0;
1024 unsigned char req[8];
1025 unsigned char prefix = DRBG_PREFIX3;
1026 struct drbg_string data1, data2;
1027
1028 /* 10.1.1.4 step 2 */
1029 ret = drbg_hash_process_addtl(drbg, addtl);
1030 if (ret)
1031 return ret;
1032 /* 10.1.1.4 step 3 */
1033 len = drbg_hash_hashgen(drbg, buf, buflen);
1034
1035 /* this is the value H as documented in 10.1.1.4 */
1036 memset(drbg->scratchpad, 0, drbg_blocklen(drbg));
1037 /* 10.1.1.4 step 4 */
1038 drbg_string_fill(&data1, &prefix, 1);
1039 drbg_string_fill(&data2, drbg->V, drbg_statelen(drbg));
1040 data1.next = &data2;
1041 ret = drbg_kcapi_hash(drbg, NULL, drbg->scratchpad, &data1);
1042 if (ret) {
1043 len = ret;
1044 goto out;
1045 }
1046
1047 /* 10.1.1.4 step 5 */
1048 drbg_add_buf(drbg->V, drbg_statelen(drbg),
1049 drbg->scratchpad, drbg_blocklen(drbg));
1050 drbg_add_buf(drbg->V, drbg_statelen(drbg),
1051 drbg->C, drbg_statelen(drbg));
1052 drbg_int2byte(req, drbg->reseed_ctr, sizeof(req));
1053 drbg_add_buf(drbg->V, drbg_statelen(drbg), req, 8);
1054
1055out:
1056 memset(drbg->scratchpad, 0, drbg_blocklen(drbg));
1057 return len;
1058}
1059
1060/*
1061 * scratchpad usage: as update and generate are used isolated, both
1062 * can use the scratchpad
1063 */
1064static struct drbg_state_ops drbg_hash_ops = {
1065 .update = drbg_hash_update,
1066 .generate = drbg_hash_generate,
1067 .crypto_init = drbg_init_hash_kernel,
1068 .crypto_fini = drbg_fini_hash_kernel,
1069};
1070#endif /* CONFIG_CRYPTO_DRBG_HASH */
1071
1072/******************************************************************
1073 * Functions common for DRBG implementations
1074 ******************************************************************/
1075
1076/*
1077 * Seeding or reseeding of the DRBG
1078 *
1079 * @drbg: DRBG state struct
1080 * @pers: personalization / additional information buffer
1081 * @reseed: 0 for initial seed process, 1 for reseeding
1082 *
1083 * return:
1084 * 0 on success
1085 * error value otherwise
1086 */
1087static int drbg_seed(struct drbg_state *drbg, struct drbg_string *pers,
1088 bool reseed)
1089{
1090 int ret = 0;
1091 unsigned char *entropy = NULL;
1092 size_t entropylen = 0;
1093 struct drbg_string data1;
1094
1095 /* 9.1 / 9.2 / 9.3.1 step 3 */
1096 if (pers && pers->len > (drbg_max_addtl(drbg))) {
1097 pr_devel("DRBG: personalization string too long %lu\n",
1098 pers->len);
1099 return -EINVAL;
1100 }
1101
1102 if (drbg->test_data && drbg->test_data->testentropy) {
1103 drbg_string_fill(&data1, drbg->test_data->testentropy->buf,
1104 drbg->test_data->testentropy->len);
1105 pr_devel("DRBG: using test entropy\n");
1106 } else {
1107 /*
1108 * Gather entropy equal to the security strength of the DRBG.
1109 * With a derivation function, a nonce is required in addition
1110 * to the entropy. A nonce must be at least 1/2 of the security
1111 * strength of the DRBG in size. Thus, entropy * nonce is 3/2
1112 * of the strength. The consideration of a nonce is only
1113 * applicable during initial seeding.
1114 */
1115 entropylen = drbg_sec_strength(drbg->core->flags);
1116 if (!entropylen)
1117 return -EFAULT;
1118 if (!reseed)
1119 entropylen = ((entropylen + 1) / 2) * 3;
1120 pr_devel("DRBG: (re)seeding with %zu bytes of entropy\n",
1121 entropylen);
1122 entropy = kzalloc(entropylen, GFP_KERNEL);
1123 if (!entropy)
1124 return -ENOMEM;
1125 get_random_bytes(entropy, entropylen);
1126 drbg_string_fill(&data1, entropy, entropylen);
1127 }
1128
1129 /*
1130 * concatenation of entropy with personalization str / addtl input)
1131 * the variable pers is directly handed in by the caller, so check its
1132 * contents whether it is appropriate
1133 */
1134 if (pers && pers->buf && 0 < pers->len && NULL == pers->next) {
1135 data1.next = pers;
1136 pr_devel("DRBG: using personalization string\n");
1137 }
1138
1139 ret = drbg->d_ops->update(drbg, &data1, reseed);
1140 if (ret)
1141 goto out;
1142
1143 drbg->seeded = true;
1144 /* 10.1.1.2 / 10.1.1.3 step 5 */
1145 drbg->reseed_ctr = 1;
1146
1147out:
1148 if (entropy)
1149 kzfree(entropy);
1150 return ret;
1151}
1152
1153/* Free all substructures in a DRBG state without the DRBG state structure */
1154static inline void drbg_dealloc_state(struct drbg_state *drbg)
1155{
1156 if (!drbg)
1157 return;
1158 if (drbg->V)
1159 kzfree(drbg->V);
1160 drbg->V = NULL;
1161 if (drbg->C)
1162 kzfree(drbg->C);
1163 drbg->C = NULL;
1164 if (drbg->scratchpad)
1165 kzfree(drbg->scratchpad);
1166 drbg->scratchpad = NULL;
1167 drbg->reseed_ctr = 0;
1168#ifdef CONFIG_CRYPTO_FIPS
1169 if (drbg->prev)
1170 kzfree(drbg->prev);
1171 drbg->prev = NULL;
1172 drbg->fips_primed = false;
1173#endif
1174}
1175
1176/*
1177 * Allocate all sub-structures for a DRBG state.
1178 * The DRBG state structure must already be allocated.
1179 */
1180static inline int drbg_alloc_state(struct drbg_state *drbg)
1181{
1182 int ret = -ENOMEM;
1183 unsigned int sb_size = 0;
1184
1185 if (!drbg)
1186 return -EINVAL;
1187
1188 drbg->V = kzalloc(drbg_statelen(drbg), GFP_KERNEL);
1189 if (!drbg->V)
1190 goto err;
1191 drbg->C = kzalloc(drbg_statelen(drbg), GFP_KERNEL);
1192 if (!drbg->C)
1193 goto err;
1194#ifdef CONFIG_CRYPTO_FIPS
1195 drbg->prev = kzalloc(drbg_blocklen(drbg), GFP_KERNEL);
1196 if (!drbg->prev)
1197 goto err;
1198 drbg->fips_primed = false;
1199#endif
1200 /* scratchpad is only generated for CTR and Hash */
1201 if (drbg->core->flags & DRBG_HMAC)
1202 sb_size = 0;
1203 else if (drbg->core->flags & DRBG_CTR)
1204 sb_size = drbg_statelen(drbg) + drbg_blocklen(drbg) + /* temp */
1205 drbg_statelen(drbg) + /* df_data */
1206 drbg_blocklen(drbg) + /* pad */
1207 drbg_blocklen(drbg) + /* iv */
1208 drbg_statelen(drbg); /* temp */
1209 else
1210 sb_size = drbg_statelen(drbg) + drbg_blocklen(drbg);
1211
1212 if (0 < sb_size) {
1213 drbg->scratchpad = kzalloc(sb_size, GFP_KERNEL);
1214 if (!drbg->scratchpad)
1215 goto err;
1216 }
1217 spin_lock_init(&drbg->drbg_lock);
1218 return 0;
1219
1220err:
1221 drbg_dealloc_state(drbg);
1222 return ret;
1223}
1224
1225/*
1226 * Strategy to avoid holding long term locks: generate a shadow copy of DRBG
1227 * and perform all operations on this shadow copy. After finishing, restore
1228 * the updated state of the shadow copy into original drbg state. This way,
1229 * only the read and write operations of the original drbg state must be
1230 * locked
1231 */
1232static inline void drbg_copy_drbg(struct drbg_state *src,
1233 struct drbg_state *dst)
1234{
1235 if (!src || !dst)
1236 return;
1237 memcpy(dst->V, src->V, drbg_statelen(src));
1238 memcpy(dst->C, src->C, drbg_statelen(src));
1239 dst->reseed_ctr = src->reseed_ctr;
1240 dst->seeded = src->seeded;
1241 dst->pr = src->pr;
1242#ifdef CONFIG_CRYPTO_FIPS
1243 dst->fips_primed = src->fips_primed;
1244 memcpy(dst->prev, src->prev, drbg_blocklen(src));
1245#endif
1246 /*
1247 * Not copied:
1248 * scratchpad is initialized drbg_alloc_state;
1249 * priv_data is initialized with call to crypto_init;
1250 * d_ops and core are set outside, as these parameters are const;
1251 * test_data is set outside to prevent it being copied back.
1252 */
1253}
1254
1255static int drbg_make_shadow(struct drbg_state *drbg, struct drbg_state **shadow)
1256{
1257 int ret = -ENOMEM;
1258 struct drbg_state *tmp = NULL;
1259
1260 if (!drbg || !drbg->core || !drbg->V || !drbg->C) {
1261 pr_devel("DRBG: attempt to generate shadow copy for "
1262 "uninitialized DRBG state rejected\n");
1263 return -EINVAL;
1264 }
1265 /* HMAC does not have a scratchpad */
1266 if (!(drbg->core->flags & DRBG_HMAC) && NULL == drbg->scratchpad)
1267 return -EINVAL;
1268
1269 tmp = kzalloc(sizeof(struct drbg_state), GFP_KERNEL);
1270 if (!tmp)
1271 return -ENOMEM;
1272
1273 /* read-only data as they are defined as const, no lock needed */
1274 tmp->core = drbg->core;
1275 tmp->d_ops = drbg->d_ops;
1276
1277 ret = drbg_alloc_state(tmp);
1278 if (ret)
1279 goto err;
1280
1281 spin_lock_bh(&drbg->drbg_lock);
1282 drbg_copy_drbg(drbg, tmp);
1283 /* only make a link to the test buffer, as we only read that data */
1284 tmp->test_data = drbg->test_data;
1285 spin_unlock_bh(&drbg->drbg_lock);
1286 *shadow = tmp;
1287 return 0;
1288
1289err:
1290 if (tmp)
1291 kzfree(tmp);
1292 return ret;
1293}
1294
1295static void drbg_restore_shadow(struct drbg_state *drbg,
1296 struct drbg_state **shadow)
1297{
1298 struct drbg_state *tmp = *shadow;
1299
1300 spin_lock_bh(&drbg->drbg_lock);
1301 drbg_copy_drbg(tmp, drbg);
1302 spin_unlock_bh(&drbg->drbg_lock);
1303 drbg_dealloc_state(tmp);
1304 kzfree(tmp);
1305 *shadow = NULL;
1306}
1307
1308/*************************************************************************
1309 * DRBG interface functions
1310 *************************************************************************/
1311
1312/*
1313 * DRBG generate function as required by SP800-90A - this function
1314 * generates random numbers
1315 *
1316 * @drbg DRBG state handle
1317 * @buf Buffer where to store the random numbers -- the buffer must already
1318 * be pre-allocated by caller
1319 * @buflen Length of output buffer - this value defines the number of random
1320 * bytes pulled from DRBG
1321 * @addtl Additional input that is mixed into state, may be NULL -- note
1322 * the entropy is pulled by the DRBG internally unconditionally
1323 * as defined in SP800-90A. The additional input is mixed into
1324 * the state in addition to the pulled entropy.
1325 *
1326 * return: generated number of bytes
1327 */
1328static int drbg_generate(struct drbg_state *drbg,
1329 unsigned char *buf, unsigned int buflen,
1330 struct drbg_string *addtl)
1331{
1332 int len = 0;
1333 struct drbg_state *shadow = NULL;
1334
1335 if (0 == buflen || !buf) {
1336 pr_devel("DRBG: no output buffer provided\n");
1337 return -EINVAL;
1338 }
1339 if (addtl && NULL == addtl->buf && 0 < addtl->len) {
1340 pr_devel("DRBG: wrong format of additional information\n");
1341 return -EINVAL;
1342 }
1343
1344 len = drbg_make_shadow(drbg, &shadow);
1345 if (len) {
1346 pr_devel("DRBG: shadow copy cannot be generated\n");
1347 return len;
1348 }
1349
1350 /* 9.3.1 step 2 */
1351 len = -EINVAL;
1352 if (buflen > (drbg_max_request_bytes(shadow))) {
1353 pr_devel("DRBG: requested random numbers too large %u\n",
1354 buflen);
1355 goto err;
1356 }
1357
1358 /* 9.3.1 step 3 is implicit with the chosen DRBG */
1359
1360 /* 9.3.1 step 4 */
1361 if (addtl && addtl->len > (drbg_max_addtl(shadow))) {
1362 pr_devel("DRBG: additional information string too long %zu\n",
1363 addtl->len);
1364 goto err;
1365 }
1366 /* 9.3.1 step 5 is implicit with the chosen DRBG */
1367
1368 /*
1369 * 9.3.1 step 6 and 9 supplemented by 9.3.2 step c is implemented
1370 * here. The spec is a bit convoluted here, we make it simpler.
1371 */
1372 if ((drbg_max_requests(shadow)) < shadow->reseed_ctr)
1373 shadow->seeded = false;
1374
1375 /* allocate cipher handle */
1376 if (shadow->d_ops->crypto_init) {
1377 len = shadow->d_ops->crypto_init(shadow);
1378 if (len)
1379 goto err;
1380 }
1381
1382 if (shadow->pr || !shadow->seeded) {
1383 pr_devel("DRBG: reseeding before generation (prediction "
1384 "resistance: %s, state %s)\n",
1385 drbg->pr ? "true" : "false",
1386 drbg->seeded ? "seeded" : "unseeded");
1387 /* 9.3.1 steps 7.1 through 7.3 */
1388 len = drbg_seed(shadow, addtl, true);
1389 if (len)
1390 goto err;
1391 /* 9.3.1 step 7.4 */
1392 addtl = NULL;
1393 }
1394 /* 9.3.1 step 8 and 10 */
1395 len = shadow->d_ops->generate(shadow, buf, buflen, addtl);
1396
1397 /* 10.1.1.4 step 6, 10.1.2.5 step 7, 10.2.1.5.2 step 7 */
1398 shadow->reseed_ctr++;
1399 if (0 >= len)
1400 goto err;
1401
1402 /*
1403 * Section 11.3.3 requires to re-perform self tests after some
1404 * generated random numbers. The chosen value after which self
1405 * test is performed is arbitrary, but it should be reasonable.
1406 * However, we do not perform the self tests because of the following
1407 * reasons: it is mathematically impossible that the initial self tests
1408 * were successfully and the following are not. If the initial would
1409 * pass and the following would not, the kernel integrity is violated.
1410 * In this case, the entire kernel operation is questionable and it
1411 * is unlikely that the integrity violation only affects the
1412 * correct operation of the DRBG.
1413 *
1414 * Albeit the following code is commented out, it is provided in
1415 * case somebody has a need to implement the test of 11.3.3.
1416 */
1417#if 0
1418 if (shadow->reseed_ctr && !(shadow->reseed_ctr % 4096)) {
1419 int err = 0;
1420 pr_devel("DRBG: start to perform self test\n");
1421 if (drbg->core->flags & DRBG_HMAC)
1422 err = alg_test("drbg_pr_hmac_sha256",
1423 "drbg_pr_hmac_sha256", 0, 0);
1424 else if (drbg->core->flags & DRBG_CTR)
1425 err = alg_test("drbg_pr_ctr_aes128",
1426 "drbg_pr_ctr_aes128", 0, 0);
1427 else
1428 err = alg_test("drbg_pr_sha256",
1429 "drbg_pr_sha256", 0, 0);
1430 if (err) {
1431 pr_err("DRBG: periodical self test failed\n");
1432 /*
1433 * uninstantiate implies that from now on, only errors
1434 * are returned when reusing this DRBG cipher handle
1435 */
1436 drbg_uninstantiate(drbg);
1437 drbg_dealloc_state(shadow);
1438 kzfree(shadow);
1439 return 0;
1440 } else {
1441 pr_devel("DRBG: self test successful\n");
1442 }
1443 }
1444#endif
1445
1446err:
1447 if (shadow->d_ops->crypto_fini)
1448 shadow->d_ops->crypto_fini(shadow);
1449 drbg_restore_shadow(drbg, &shadow);
1450 return len;
1451}
1452
1453/*
1454 * Wrapper around drbg_generate which can pull arbitrary long strings
1455 * from the DRBG without hitting the maximum request limitation.
1456 *
1457 * Parameters: see drbg_generate
1458 * Return codes: see drbg_generate -- if one drbg_generate request fails,
1459 * the entire drbg_generate_long request fails
1460 */
1461static int drbg_generate_long(struct drbg_state *drbg,
1462 unsigned char *buf, unsigned int buflen,
1463 struct drbg_string *addtl)
1464{
1465 int len = 0;
1466 unsigned int slice = 0;
1467 do {
1468 int tmplen = 0;
1469 unsigned int chunk = 0;
1470 slice = ((buflen - len) / drbg_max_request_bytes(drbg));
1471 chunk = slice ? drbg_max_request_bytes(drbg) : (buflen - len);
1472 tmplen = drbg_generate(drbg, buf + len, chunk, addtl);
1473 if (0 >= tmplen)
1474 return tmplen;
1475 len += tmplen;
1476 } while (slice > 0);
1477 return len;
1478}
1479
1480/*
1481 * DRBG instantiation function as required by SP800-90A - this function
1482 * sets up the DRBG handle, performs the initial seeding and all sanity
1483 * checks required by SP800-90A
1484 *
1485 * @drbg memory of state -- if NULL, new memory is allocated
1486 * @pers Personalization string that is mixed into state, may be NULL -- note
1487 * the entropy is pulled by the DRBG internally unconditionally
1488 * as defined in SP800-90A. The additional input is mixed into
1489 * the state in addition to the pulled entropy.
1490 * @coreref reference to core
1491 * @pr prediction resistance enabled
1492 *
1493 * return
1494 * 0 on success
1495 * error value otherwise
1496 */
1497static int drbg_instantiate(struct drbg_state *drbg, struct drbg_string *pers,
1498 int coreref, bool pr)
1499{
1500 int ret = -ENOMEM;
1501
1502 pr_devel("DRBG: Initializing DRBG core %d with prediction resistance "
1503 "%s\n", coreref, pr ? "enabled" : "disabled");
1504 drbg->core = &drbg_cores[coreref];
1505 drbg->pr = pr;
1506 drbg->seeded = false;
1507 switch (drbg->core->flags & DRBG_TYPE_MASK) {
1508#ifdef CONFIG_CRYPTO_DRBG_HMAC
1509 case DRBG_HMAC:
1510 drbg->d_ops = &drbg_hmac_ops;
1511 break;
1512#endif /* CONFIG_CRYPTO_DRBG_HMAC */
1513#ifdef CONFIG_CRYPTO_DRBG_HASH
1514 case DRBG_HASH:
1515 drbg->d_ops = &drbg_hash_ops;
1516 break;
1517#endif /* CONFIG_CRYPTO_DRBG_HASH */
1518#ifdef CONFIG_CRYPTO_DRBG_CTR
1519 case DRBG_CTR:
1520 drbg->d_ops = &drbg_ctr_ops;
1521 break;
1522#endif /* CONFIG_CRYPTO_DRBG_CTR */
1523 default:
1524 return -EOPNOTSUPP;
1525 }
1526
1527 /* 9.1 step 1 is implicit with the selected DRBG type */
1528
1529 /*
1530 * 9.1 step 2 is implicit as caller can select prediction resistance
1531 * and the flag is copied into drbg->flags --
1532 * all DRBG types support prediction resistance
1533 */
1534
1535 /* 9.1 step 4 is implicit in drbg_sec_strength */
1536
1537 ret = drbg_alloc_state(drbg);
1538 if (ret)
1539 return ret;
1540
1541 ret = -EFAULT;
1542 if (drbg->d_ops->crypto_init && drbg->d_ops->crypto_init(drbg))
1543 goto err;
1544 ret = drbg_seed(drbg, pers, false);
1545 if (drbg->d_ops->crypto_fini)
1546 drbg->d_ops->crypto_fini(drbg);
1547 if (ret)
1548 goto err;
1549
1550 return 0;
1551
1552err:
1553 drbg_dealloc_state(drbg);
1554 return ret;
1555}
1556
1557/*
1558 * DRBG uninstantiate function as required by SP800-90A - this function
1559 * frees all buffers and the DRBG handle
1560 *
1561 * @drbg DRBG state handle
1562 *
1563 * return
1564 * 0 on success
1565 */
1566static int drbg_uninstantiate(struct drbg_state *drbg)
1567{
1568 spin_lock_bh(&drbg->drbg_lock);
1569 drbg_dealloc_state(drbg);
1570 /* no scrubbing of test_data -- this shall survive an uninstantiate */
1571 spin_unlock_bh(&drbg->drbg_lock);
1572 return 0;
1573}
1574
1575/*
1576 * Helper function for setting the test data in the DRBG
1577 *
1578 * @drbg DRBG state handle
1579 * @test_data test data to sets
1580 */
1581static inline void drbg_set_testdata(struct drbg_state *drbg,
1582 struct drbg_test_data *test_data)
1583{
1584 if (!test_data || !test_data->testentropy)
1585 return;
1586 spin_lock_bh(&drbg->drbg_lock);
1587 drbg->test_data = test_data;
1588 spin_unlock_bh(&drbg->drbg_lock);
1589}
1590
1591/***************************************************************
1592 * Kernel crypto API cipher invocations requested by DRBG
1593 ***************************************************************/
1594
1595#if defined(CONFIG_CRYPTO_DRBG_HASH) || defined(CONFIG_CRYPTO_DRBG_HMAC)
1596struct sdesc {
1597 struct shash_desc shash;
1598 char ctx[];
1599};
1600
1601static int drbg_init_hash_kernel(struct drbg_state *drbg)
1602{
1603 struct sdesc *sdesc;
1604 struct crypto_shash *tfm;
1605
1606 tfm = crypto_alloc_shash(drbg->core->backend_cra_name, 0, 0);
1607 if (IS_ERR(tfm)) {
1608 pr_info("DRBG: could not allocate digest TFM handle\n");
1609 return PTR_ERR(tfm);
1610 }
1611 BUG_ON(drbg_blocklen(drbg) != crypto_shash_digestsize(tfm));
1612 sdesc = kzalloc(sizeof(struct shash_desc) + crypto_shash_descsize(tfm),
1613 GFP_KERNEL);
1614 if (!sdesc) {
1615 crypto_free_shash(tfm);
1616 return -ENOMEM;
1617 }
1618
1619 sdesc->shash.tfm = tfm;
1620 sdesc->shash.flags = 0;
1621 drbg->priv_data = sdesc;
1622 return 0;
1623}
1624
1625static int drbg_fini_hash_kernel(struct drbg_state *drbg)
1626{
1627 struct sdesc *sdesc = (struct sdesc *)drbg->priv_data;
1628 if (sdesc) {
1629 crypto_free_shash(sdesc->shash.tfm);
1630 kzfree(sdesc);
1631 }
1632 drbg->priv_data = NULL;
1633 return 0;
1634}
1635
1636static int drbg_kcapi_hash(struct drbg_state *drbg, const unsigned char *key,
1637 unsigned char *outval, const struct drbg_string *in)
1638{
1639 struct sdesc *sdesc = (struct sdesc *)drbg->priv_data;
1640
1641 if (key)
1642 crypto_shash_setkey(sdesc->shash.tfm, key, drbg_statelen(drbg));
1643 crypto_shash_init(&sdesc->shash);
1644 for (; NULL != in; in = in->next)
1645 crypto_shash_update(&sdesc->shash, in->buf, in->len);
1646 return crypto_shash_final(&sdesc->shash, outval);
1647}
1648#endif /* (CONFIG_CRYPTO_DRBG_HASH || CONFIG_CRYPTO_DRBG_HMAC) */
1649
1650#ifdef CONFIG_CRYPTO_DRBG_CTR
1651static int drbg_init_sym_kernel(struct drbg_state *drbg)
1652{
1653 int ret = 0;
1654 struct crypto_blkcipher *tfm;
1655
1656 tfm = crypto_alloc_blkcipher(drbg->core->backend_cra_name, 0, 0);
1657 if (IS_ERR(tfm)) {
1658 pr_info("DRBG: could not allocate cipher TFM handle\n");
1659 return PTR_ERR(tfm);
1660 }
1661 BUG_ON(drbg_blocklen(drbg) != crypto_blkcipher_blocksize(tfm));
1662 drbg->priv_data = tfm;
1663 return ret;
1664}
1665
1666static int drbg_fini_sym_kernel(struct drbg_state *drbg)
1667{
1668 struct crypto_blkcipher *tfm =
1669 (struct crypto_blkcipher *)drbg->priv_data;
1670 if (tfm)
1671 crypto_free_blkcipher(tfm);
1672 drbg->priv_data = NULL;
1673 return 0;
1674}
1675
1676static int drbg_kcapi_sym(struct drbg_state *drbg, const unsigned char *key,
1677 unsigned char *outval, const struct drbg_string *in)
1678{
1679 int ret = 0;
1680 struct scatterlist sg_in, sg_out;
1681 struct blkcipher_desc desc;
1682 struct crypto_blkcipher *tfm =
1683 (struct crypto_blkcipher *)drbg->priv_data;
1684
1685 desc.tfm = tfm;
1686 desc.flags = 0;
1687 crypto_blkcipher_setkey(tfm, key, (drbg_keylen(drbg)));
1688 /* there is only component in *in */
1689 sg_init_one(&sg_in, in->buf, in->len);
1690 sg_init_one(&sg_out, outval, drbg_blocklen(drbg));
1691 ret = crypto_blkcipher_encrypt(&desc, &sg_out, &sg_in, in->len);
1692
1693 return ret;
1694}
1695#endif /* CONFIG_CRYPTO_DRBG_CTR */
1696
1697/***************************************************************
1698 * Kernel crypto API interface to register DRBG
1699 ***************************************************************/
1700
1701/*
1702 * Look up the DRBG flags by given kernel crypto API cra_name
1703 * The code uses the drbg_cores definition to do this
1704 *
1705 * @cra_name kernel crypto API cra_name
1706 * @coreref reference to integer which is filled with the pointer to
1707 * the applicable core
1708 * @pr reference for setting prediction resistance
1709 *
1710 * return: flags
1711 */
1712static inline void drbg_convert_tfm_core(const char *cra_driver_name,
1713 int *coreref, bool *pr)
1714{
1715 int i = 0;
1716 size_t start = 0;
1717 int len = 0;
1718
1719 *pr = true;
1720 /* disassemble the names */
1721 if (!memcmp(cra_driver_name, "drbg_nopr_", 10)) {
1722 start = 10;
1723 *pr = false;
1724 } else if (!memcmp(cra_driver_name, "drbg_pr_", 8)) {
1725 start = 8;
1726 } else {
1727 return;
1728 }
1729
1730 /* remove the first part */
1731 len = strlen(cra_driver_name) - start;
1732 for (i = 0; ARRAY_SIZE(drbg_cores) > i; i++) {
1733 if (!memcmp(cra_driver_name + start, drbg_cores[i].cra_name,
1734 len)) {
1735 *coreref = i;
1736 return;
1737 }
1738 }
1739}
1740
1741static int drbg_kcapi_init(struct crypto_tfm *tfm)
1742{
1743 struct drbg_state *drbg = crypto_tfm_ctx(tfm);
1744 bool pr = false;
1745 int coreref = 0;
1746
1747 drbg_convert_tfm_core(crypto_tfm_alg_name(tfm), &coreref, &pr);
1748 /*
1749 * when personalization string is needed, the caller must call reset
1750 * and provide the personalization string as seed information
1751 */
1752 return drbg_instantiate(drbg, NULL, coreref, pr);
1753}
1754
1755static void drbg_kcapi_cleanup(struct crypto_tfm *tfm)
1756{
1757 drbg_uninstantiate(crypto_tfm_ctx(tfm));
1758}
1759
1760/*
1761 * Generate random numbers invoked by the kernel crypto API:
1762 * The API of the kernel crypto API is extended as follows:
1763 *
1764 * If dlen is larger than zero, rdata is interpreted as the output buffer
1765 * where random data is to be stored.
1766 *
1767 * If dlen is zero, rdata is interpreted as a pointer to a struct drbg_gen
1768 * which holds the additional information string that is used for the
1769 * DRBG generation process. The output buffer that is to be used to store
1770 * data is also pointed to by struct drbg_gen.
1771 */
1772static int drbg_kcapi_random(struct crypto_rng *tfm, u8 *rdata,
1773 unsigned int dlen)
1774{
1775 struct drbg_state *drbg = crypto_rng_ctx(tfm);
1776 if (0 < dlen) {
1777 return drbg_generate_long(drbg, rdata, dlen, NULL);
1778 } else {
1779 struct drbg_gen *data = (struct drbg_gen *)rdata;
1780 /* catch NULL pointer */
1781 if (!data)
1782 return 0;
1783 drbg_set_testdata(drbg, data->test_data);
1784 return drbg_generate_long(drbg, data->outbuf, data->outlen,
1785 data->addtl);
1786 }
1787}
1788
1789/*
1790 * Reset the DRBG invoked by the kernel crypto API
1791 * The reset implies a full re-initialization of the DRBG. Similar to the
1792 * generate function of drbg_kcapi_random, this function extends the
1793 * kernel crypto API interface with struct drbg_gen
1794 */
1795static int drbg_kcapi_reset(struct crypto_rng *tfm, u8 *seed, unsigned int slen)
1796{
1797 struct drbg_state *drbg = crypto_rng_ctx(tfm);
1798 struct crypto_tfm *tfm_base = crypto_rng_tfm(tfm);
1799 bool pr = false;
1800 struct drbg_string seed_string;
1801 int coreref = 0;
1802
1803 drbg_uninstantiate(drbg);
1804 drbg_convert_tfm_core(crypto_tfm_alg_driver_name(tfm_base), &coreref,
1805 &pr);
1806 if (0 < slen) {
1807 drbg_string_fill(&seed_string, seed, slen);
1808 return drbg_instantiate(drbg, &seed_string, coreref, pr);
1809 } else {
1810 struct drbg_gen *data = (struct drbg_gen *)seed;
1811 /* allow invocation of API call with NULL, 0 */
1812 if (!data)
1813 return drbg_instantiate(drbg, NULL, coreref, pr);
1814 drbg_set_testdata(drbg, data->test_data);
1815 return drbg_instantiate(drbg, data->addtl, coreref, pr);
1816 }
1817}
1818
1819/***************************************************************
1820 * Kernel module: code to load the module
1821 ***************************************************************/
1822
1823/*
1824 * Tests as defined in 11.3.2 in addition to the cipher tests: testing
1825 * of the error handling.
1826 *
1827 * Note: testing of failing seed source as defined in 11.3.2 is not applicable
1828 * as seed source of get_random_bytes does not fail.
1829 *
1830 * Note 2: There is no sensible way of testing the reseed counter
1831 * enforcement, so skip it.
1832 */
1833static inline int __init drbg_healthcheck_sanity(void)
1834{
1835#ifdef CONFIG_CRYPTO_FIPS
1836 int len = 0;
1837#define OUTBUFLEN 16
1838 unsigned char buf[OUTBUFLEN];
1839 struct drbg_state *drbg = NULL;
1840 int ret = -EFAULT;
1841 int rc = -EFAULT;
1842 bool pr = false;
1843 int coreref = 0;
1844 struct drbg_string addtl;
1845 size_t max_addtllen, max_request_bytes;
1846
1847 /* only perform test in FIPS mode */
1848 if (!fips_enabled)
1849 return 0;
1850
1851#ifdef CONFIG_CRYPTO_DRBG_CTR
1852 drbg_convert_tfm_core("drbg_nopr_ctr_aes128", &coreref, &pr);
1853#elif CONFIG_CRYPTO_DRBG_HASH
1854 drbg_convert_tfm_core("drbg_nopr_sha256", &coreref, &pr);
1855#else
1856 drbg_convert_tfm_core("drbg_nopr_hmac_sha256", &coreref, &pr);
1857#endif
1858
1859 drbg = kzalloc(sizeof(struct drbg_state), GFP_KERNEL);
1860 if (!drbg)
1861 return -ENOMEM;
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 /* test uninstantated DRBG */
1892 len = drbg_generate(drbg, buf, (max_request_bytes + 1), NULL);
1893 BUG_ON(0 < len);
1894 /* all tests passed */
1895 rc = 0;
1896
1897 pr_devel("DRBG: Sanity tests for failure code paths successfully "
1898 "completed\n");
1899
1900 drbg_uninstantiate(drbg);
1901outbuf:
1902 kzfree(drbg);
1903 return rc;
1904#else /* CONFIG_CRYPTO_FIPS */
1905 return 0;
1906#endif /* CONFIG_CRYPTO_FIPS */
1907}
1908
1909static struct crypto_alg drbg_algs[22];
1910
1911/*
1912 * Fill the array drbg_algs used to register the different DRBGs
1913 * with the kernel crypto API. To fill the array, the information
1914 * from drbg_cores[] is used.
1915 */
1916static inline void __init drbg_fill_array(struct crypto_alg *alg,
1917 const struct drbg_core *core, int pr)
1918{
1919 int pos = 0;
1920 static int priority = 100;
1921
1922 memset(alg, 0, sizeof(struct crypto_alg));
1923 memcpy(alg->cra_name, "stdrng", 6);
1924 if (pr) {
1925 memcpy(alg->cra_driver_name, "drbg_pr_", 8);
1926 pos = 8;
1927 } else {
1928 memcpy(alg->cra_driver_name, "drbg_nopr_", 10);
1929 pos = 10;
1930 }
1931 memcpy(alg->cra_driver_name + pos, core->cra_name,
1932 strlen(core->cra_name));
1933
1934 alg->cra_priority = priority;
1935 priority++;
1936 /*
1937 * If FIPS mode enabled, the selected DRBG shall have the
1938 * highest cra_priority over other stdrng instances to ensure
1939 * it is selected.
1940 */
1941 if (fips_enabled)
1942 alg->cra_priority += 200;
1943
1944 alg->cra_flags = CRYPTO_ALG_TYPE_RNG;
1945 alg->cra_ctxsize = sizeof(struct drbg_state);
1946 alg->cra_type = &crypto_rng_type;
1947 alg->cra_module = THIS_MODULE;
1948 alg->cra_init = drbg_kcapi_init;
1949 alg->cra_exit = drbg_kcapi_cleanup;
1950 alg->cra_u.rng.rng_make_random = drbg_kcapi_random;
1951 alg->cra_u.rng.rng_reset = drbg_kcapi_reset;
1952 alg->cra_u.rng.seedsize = 0;
1953}
1954
1955static int __init drbg_init(void)
1956{
1957 unsigned int i = 0; /* pointer to drbg_algs */
1958 unsigned int j = 0; /* pointer to drbg_cores */
1959 int ret = -EFAULT;
1960
1961 ret = drbg_healthcheck_sanity();
1962 if (ret)
1963 return ret;
1964
1965 if (ARRAY_SIZE(drbg_cores) * 2 > ARRAY_SIZE(drbg_algs)) {
1966 pr_info("DRBG: Cannot register all DRBG types"
1967 "(slots needed: %lu, slots available: %lu)\n",
1968 ARRAY_SIZE(drbg_cores) * 2, ARRAY_SIZE(drbg_algs));
1969 return ret;
1970 }
1971
1972 /*
1973 * each DRBG definition can be used with PR and without PR, thus
1974 * we instantiate each DRBG in drbg_cores[] twice.
1975 *
1976 * As the order of placing them into the drbg_algs array matters
1977 * (the later DRBGs receive a higher cra_priority) we register the
1978 * prediction resistance DRBGs first as the should not be too
1979 * interesting.
1980 */
1981 for (j = 0; ARRAY_SIZE(drbg_cores) > j; j++, i++)
1982 drbg_fill_array(&drbg_algs[i], &drbg_cores[j], 1);
1983 for (j = 0; ARRAY_SIZE(drbg_cores) > j; j++, i++)
1984 drbg_fill_array(&drbg_algs[i], &drbg_cores[j], 0);
1985 return crypto_register_algs(drbg_algs, (ARRAY_SIZE(drbg_cores) * 2));
1986}
1987
1988void __exit drbg_exit(void)
1989{
1990 crypto_unregister_algs(drbg_algs, (ARRAY_SIZE(drbg_cores) * 2));
1991}
1992
1993module_init(drbg_init);
1994module_exit(drbg_exit);
1995MODULE_LICENSE("GPL");
1996MODULE_AUTHOR("Stephan Mueller <smueller@chronox.de>");
1997MODULE_DESCRIPTION("NIST SP800-90A Deterministic Random Bit Generator (DRBG) using following cores:"
1998#ifdef CONFIG_CRYPTO_DRBG_HMAC
1999"HMAC "
2000#endif
2001#ifdef CONFIG_CRYPTO_DRBG_HASH
2002"Hash "
2003#endif
2004#ifdef CONFIG_CRYPTO_DRBG_CTR
2005"CTR"
2006#endif
2007);
generated by cgit v1.2.2 (git 2.25.0) at 2024-11-24 20:02:32 -0500