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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/***************************************************************
103 * Backend cipher definitions available to DRBG
104 ***************************************************************/
105
106/*
107 * The order of the DRBG definitions here matter: every DRBG is registered
108 * as stdrng. Each DRBG receives an increasing cra_priority values the later
109 * they are defined in this array (see drbg_fill_array).
110 *
111 * HMAC DRBGs are favored over Hash DRBGs over CTR DRBGs, and
112 * the SHA256 / AES 256 over other ciphers. Thus, the favored
113 * DRBGs are the latest entries in this array.
114 */
115static const struct drbg_core drbg_cores[] = {
116#ifdef CONFIG_CRYPTO_DRBG_CTR
117 {
118 .flags = DRBG_CTR | DRBG_STRENGTH128,
119 .statelen = 32, /* 256 bits as defined in 10.2.1 */
120 .max_addtllen = 35,
121 .max_bits = 19,
122 .max_req = 48,
123 .blocklen_bytes = 16,
124 .cra_name = "ctr_aes128",
125 .backend_cra_name = "ecb(aes)",
126 }, {
127 .flags = DRBG_CTR | DRBG_STRENGTH192,
128 .statelen = 40, /* 320 bits as defined in 10.2.1 */
129 .max_addtllen = 35,
130 .max_bits = 19,
131 .max_req = 48,
132 .blocklen_bytes = 16,
133 .cra_name = "ctr_aes192",
134 .backend_cra_name = "ecb(aes)",
135 }, {
136 .flags = DRBG_CTR | DRBG_STRENGTH256,
137 .statelen = 48, /* 384 bits as defined in 10.2.1 */
138 .max_addtllen = 35,
139 .max_bits = 19,
140 .max_req = 48,
141 .blocklen_bytes = 16,
142 .cra_name = "ctr_aes256",
143 .backend_cra_name = "ecb(aes)",
144 },
145#endif /* CONFIG_CRYPTO_DRBG_CTR */
146#ifdef CONFIG_CRYPTO_DRBG_HASH
147 {
148 .flags = DRBG_HASH | DRBG_STRENGTH128,
149 .statelen = 55, /* 440 bits */
150 .max_addtllen = 35,
151 .max_bits = 19,
152 .max_req = 48,
153 .blocklen_bytes = 20,
154 .cra_name = "sha1",
155 .backend_cra_name = "sha1",
156 }, {
157 .flags = DRBG_HASH | DRBG_STRENGTH256,
158 .statelen = 111, /* 888 bits */
159 .max_addtllen = 35,
160 .max_bits = 19,
161 .max_req = 48,
162 .blocklen_bytes = 48,
163 .cra_name = "sha384",
164 .backend_cra_name = "sha384",
165 }, {
166 .flags = DRBG_HASH | DRBG_STRENGTH256,
167 .statelen = 111, /* 888 bits */
168 .max_addtllen = 35,
169 .max_bits = 19,
170 .max_req = 48,
171 .blocklen_bytes = 64,
172 .cra_name = "sha512",
173 .backend_cra_name = "sha512",
174 }, {
175 .flags = DRBG_HASH | DRBG_STRENGTH256,
176 .statelen = 55, /* 440 bits */
177 .max_addtllen = 35,
178 .max_bits = 19,
179 .max_req = 48,
180 .blocklen_bytes = 32,
181 .cra_name = "sha256",
182 .backend_cra_name = "sha256",
183 },
184#endif /* CONFIG_CRYPTO_DRBG_HASH */
185#ifdef CONFIG_CRYPTO_DRBG_HMAC
186 {
187 .flags = DRBG_HMAC | DRBG_STRENGTH128,
188 .statelen = 20, /* block length of cipher */
189 .max_addtllen = 35,
190 .max_bits = 19,
191 .max_req = 48,
192 .blocklen_bytes = 20,
193 .cra_name = "hmac_sha1",
194 .backend_cra_name = "hmac(sha1)",
195 }, {
196 .flags = DRBG_HMAC | DRBG_STRENGTH256,
197 .statelen = 48, /* block length of cipher */
198 .max_addtllen = 35,
199 .max_bits = 19,
200 .max_req = 48,
201 .blocklen_bytes = 48,
202 .cra_name = "hmac_sha384",
203 .backend_cra_name = "hmac(sha384)",
204 }, {
205 .flags = DRBG_HMAC | DRBG_STRENGTH256,
206 .statelen = 64, /* block length of cipher */
207 .max_addtllen = 35,
208 .max_bits = 19,
209 .max_req = 48,
210 .blocklen_bytes = 64,
211 .cra_name = "hmac_sha512",
212 .backend_cra_name = "hmac(sha512)",
213 }, {
214 .flags = DRBG_HMAC | DRBG_STRENGTH256,
215 .statelen = 32, /* block length of cipher */
216 .max_addtllen = 35,
217 .max_bits = 19,
218 .max_req = 48,
219 .blocklen_bytes = 32,
220 .cra_name = "hmac_sha256",
221 .backend_cra_name = "hmac(sha256)",
222 },
223#endif /* CONFIG_CRYPTO_DRBG_HMAC */
224};
225
226/******************************************************************
227 * Generic helper functions
228 ******************************************************************/
229
230/*
231 * Return strength of DRBG according to SP800-90A section 8.4
232 *
233 * @flags DRBG flags reference
234 *
235 * Return: normalized strength in *bytes* value or 32 as default
236 * to counter programming errors
237 */
238static inline unsigned short drbg_sec_strength(drbg_flag_t flags)
239{
240 switch (flags & DRBG_STRENGTH_MASK) {
241 case DRBG_STRENGTH128:
242 return 16;
243 case DRBG_STRENGTH192:
244 return 24;
245 case DRBG_STRENGTH256:
246 return 32;
247 default:
248 return 32;
249 }
250}
251
252/*
253 * FIPS 140-2 continuous self test
254 * The test is performed on the result of one round of the output
255 * function. Thus, the function implicitly knows the size of the
256 * buffer.
257 *
258 * The FIPS test can be called in an endless loop until it returns
259 * true. Although the code looks like a potential for a deadlock, it
260 * is not the case, because returning a false cannot mathematically
261 * occur (except once when a reseed took place and the updated state
262 * would is now set up such that the generation of new value returns
263 * an identical one -- this is most unlikely and would happen only once).
264 * Thus, if this function repeatedly returns false and thus would cause
265 * a deadlock, the integrity of the entire kernel is lost.
266 *
267 * @drbg DRBG handle
268 * @buf output buffer of random data to be checked
269 *
270 * return:
271 * true on success
272 * false on error
273 */
274static bool drbg_fips_continuous_test(struct drbg_state *drbg,
275 const unsigned char *buf)
276{
277#ifdef CONFIG_CRYPTO_FIPS
278 int ret = 0;
279 /* skip test if we test the overall system */
280 if (drbg->test_data)
281 return true;
282 /* only perform test in FIPS mode */
283 if (0 == fips_enabled)
284 return true;
285 if (!drbg->fips_primed) {
286 /* Priming of FIPS test */
287 memcpy(drbg->prev, buf, drbg_blocklen(drbg));
288 drbg->fips_primed = true;
289 /* return false due to priming, i.e. another round is needed */
290 return false;
291 }
292 ret = memcmp(drbg->prev, buf, drbg_blocklen(drbg));
293 memcpy(drbg->prev, buf, drbg_blocklen(drbg));
294 /* the test shall pass when the two compared values are not equal */
295 return ret != 0;
296#else
297 return true;
298#endif /* CONFIG_CRYPTO_FIPS */
299}
300
301/*
302 * Convert an integer into a byte representation of this integer.
303 * The byte representation is big-endian
304 *
305 * @buf buffer holding the converted integer
306 * @val value to be converted
307 * @buflen length of buffer
308 */
309#if (defined(CONFIG_CRYPTO_DRBG_HASH) || defined(CONFIG_CRYPTO_DRBG_CTR))
310static inline void drbg_int2byte(unsigned char *buf, uint64_t val,
311 size_t buflen)
312{
313 unsigned char *byte;
314 uint64_t i;
315
316 byte = buf + (buflen - 1);
317 for (i = 0; i < buflen; i++)
318 *(byte--) = val >> (i * 8) & 0xff;
319}
320
321/*
322 * Increment buffer
323 *
324 * @dst buffer to increment
325 * @add value to add
326 */
327static inline void drbg_add_buf(unsigned char *dst, size_t dstlen,
328 const unsigned char *add, size_t addlen)
329{
330 /* implied: dstlen > addlen */
331 unsigned char *dstptr;
332 const unsigned char *addptr;
333 unsigned int remainder = 0;
334 size_t len = addlen;
335
336 dstptr = dst + (dstlen-1);
337 addptr = add + (addlen-1);
338 while (len) {
339 remainder += *dstptr + *addptr;
340 *dstptr = remainder & 0xff;
341 remainder >>= 8;
342 len--; dstptr--; addptr--;
343 }
344 len = dstlen - addlen;
345 while (len && remainder > 0) {
346 remainder = *dstptr + 1;
347 *dstptr = remainder & 0xff;
348 remainder >>= 8;
349 len--; dstptr--;
350 }
351}
352#endif /* defined(CONFIG_CRYPTO_DRBG_HASH) || defined(CONFIG_CRYPTO_DRBG_CTR) */
353
354/******************************************************************
355 * CTR DRBG callback functions
356 ******************************************************************/
357
358#ifdef CONFIG_CRYPTO_DRBG_CTR
359#define CRYPTO_DRBG_CTR_STRING "CTR "
360static int drbg_kcapi_sym(struct drbg_state *drbg, const unsigned char *key,
361 unsigned char *outval, const struct drbg_string *in);
362static int drbg_init_sym_kernel(struct drbg_state *drbg);
363static int drbg_fini_sym_kernel(struct drbg_state *drbg);
364
365/* BCC function for CTR DRBG as defined in 10.4.3 */
366static int drbg_ctr_bcc(struct drbg_state *drbg,
367 unsigned char *out, const unsigned char *key,
368 struct list_head *in)
369{
370 int ret = 0;
371 struct drbg_string *curr = NULL;
372 struct drbg_string data;
373 short cnt = 0;
374
375 drbg_string_fill(&data, out, drbg_blocklen(drbg));
376
377 /* 10.4.3 step 1 */
378 memset(out, 0, drbg_blocklen(drbg));
379
380 /* 10.4.3 step 2 / 4 */
381 list_for_each_entry(curr, in, list) {
382 const unsigned char *pos = curr->buf;
383 size_t len = curr->len;
384 /* 10.4.3 step 4.1 */
385 while (len) {
386 /* 10.4.3 step 4.2 */
387 if (drbg_blocklen(drbg) == cnt) {
388 cnt = 0;
389 ret = drbg_kcapi_sym(drbg, key, out, &data);
390 if (ret)
391 return ret;
392 }
393 out[cnt] ^= *pos;
394 pos++;
395 cnt++;
396 len--;
397 }
398 }
399 /* 10.4.3 step 4.2 for last block */
400 if (cnt)
401 ret = drbg_kcapi_sym(drbg, key, out, &data);
402
403 return ret;
404}
405
406/*
407 * scratchpad usage: drbg_ctr_update is interlinked with drbg_ctr_df
408 * (and drbg_ctr_bcc, but this function does not need any temporary buffers),
409 * the scratchpad is used as follows:
410 * drbg_ctr_update:
411 * temp
412 * start: drbg->scratchpad
413 * length: drbg_statelen(drbg) + drbg_blocklen(drbg)
414 * note: the cipher writing into this variable works
415 * blocklen-wise. Now, when the statelen is not a multiple
416 * of blocklen, the generateion loop below "spills over"
417 * by at most blocklen. Thus, we need to give sufficient
418 * memory.
419 * df_data
420 * start: drbg->scratchpad +
421 * drbg_statelen(drbg) + drbg_blocklen(drbg)
422 * length: drbg_statelen(drbg)
423 *
424 * drbg_ctr_df:
425 * pad
426 * start: df_data + drbg_statelen(drbg)
427 * length: drbg_blocklen(drbg)
428 * iv
429 * start: pad + drbg_blocklen(drbg)
430 * length: drbg_blocklen(drbg)
431 * temp
432 * start: iv + drbg_blocklen(drbg)
433 * length: drbg_satelen(drbg) + drbg_blocklen(drbg)
434 * note: temp is the buffer that the BCC function operates
435 * on. BCC operates blockwise. drbg_statelen(drbg)
436 * is sufficient when the DRBG state length is a multiple
437 * of the block size. For AES192 (and maybe other ciphers)
438 * this is not correct and the length for temp is
439 * insufficient (yes, that also means for such ciphers,
440 * the final output of all BCC rounds are truncated).
441 * Therefore, add drbg_blocklen(drbg) to cover all
442 * possibilities.
443 */
444
445/* Derivation Function for CTR DRBG as defined in 10.4.2 */
446static int drbg_ctr_df(struct drbg_state *drbg,
447 unsigned char *df_data, size_t bytes_to_return,
448 struct list_head *seedlist)
449{
450 int ret = -EFAULT;
451 unsigned char L_N[8];
452 /* S3 is input */
453 struct drbg_string S1, S2, S4, cipherin;
454 LIST_HEAD(bcc_list);
455 unsigned char *pad = df_data + drbg_statelen(drbg);
456 unsigned char *iv = pad + drbg_blocklen(drbg);
457 unsigned char *temp = iv + drbg_blocklen(drbg);
458 size_t padlen = 0;
459 unsigned int templen = 0;
460 /* 10.4.2 step 7 */
461 unsigned int i = 0;
462 /* 10.4.2 step 8 */
463 const unsigned char *K = (unsigned char *)
464 "\x00\x01\x02\x03\x04\x05\x06\x07"
465 "\x08\x09\x0a\x0b\x0c\x0d\x0e\x0f"
466 "\x10\x11\x12\x13\x14\x15\x16\x17"
467 "\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f";
468 unsigned char *X;
469 size_t generated_len = 0;
470 size_t inputlen = 0;
471 struct drbg_string *seed = NULL;
472
473 memset(pad, 0, drbg_blocklen(drbg));
474 memset(iv, 0, drbg_blocklen(drbg));
475 memset(temp, 0, drbg_statelen(drbg));
476
477 /* 10.4.2 step 1 is implicit as we work byte-wise */
478
479 /* 10.4.2 step 2 */
480 if ((512/8) < bytes_to_return)
481 return -EINVAL;
482
483 /* 10.4.2 step 2 -- calculate the entire length of all input data */
484 list_for_each_entry(seed, seedlist, list)
485 inputlen += seed->len;
486 drbg_int2byte(&L_N[0], inputlen, 4);
487
488 /* 10.4.2 step 3 */
489 drbg_int2byte(&L_N[4], bytes_to_return, 4);
490
491 /* 10.4.2 step 5: length is L_N, input_string, one byte, padding */
492 padlen = (inputlen + sizeof(L_N) + 1) % (drbg_blocklen(drbg));
493 /* wrap the padlen appropriately */
494 if (padlen)
495 padlen = drbg_blocklen(drbg) - padlen;
496 /*
497 * pad / padlen contains the 0x80 byte and the following zero bytes.
498 * As the calculated padlen value only covers the number of zero
499 * bytes, this value has to be incremented by one for the 0x80 byte.
500 */
501 padlen++;
502 pad[0] = 0x80;
503
504 /* 10.4.2 step 4 -- first fill the linked list and then order it */
505 drbg_string_fill(&S1, iv, drbg_blocklen(drbg));
506 list_add_tail(&S1.list, &bcc_list);
507 drbg_string_fill(&S2, L_N, sizeof(L_N));
508 list_add_tail(&S2.list, &bcc_list);
509 list_splice_tail(seedlist, &bcc_list);
510 drbg_string_fill(&S4, pad, padlen);
511 list_add_tail(&S4.list, &bcc_list);
512
513 /* 10.4.2 step 9 */
514 while (templen < (drbg_keylen(drbg) + (drbg_blocklen(drbg)))) {
515 /*
516 * 10.4.2 step 9.1 - the padding is implicit as the buffer
517 * holds zeros after allocation -- even the increment of i
518 * is irrelevant as the increment remains within length of i
519 */
520 drbg_int2byte(iv, i, 4);
521 /* 10.4.2 step 9.2 -- BCC and concatenation with temp */
522 ret = drbg_ctr_bcc(drbg, temp + templen, K, &bcc_list);
523 if (ret)
524 goto out;
525 /* 10.4.2 step 9.3 */
526 i++;
527 templen += drbg_blocklen(drbg);
528 }
529
530 /* 10.4.2 step 11 */
531 X = temp + (drbg_keylen(drbg));
532 drbg_string_fill(&cipherin, X, drbg_blocklen(drbg));
533
534 /* 10.4.2 step 12: overwriting of outval is implemented in next step */
535
536 /* 10.4.2 step 13 */
537 while (generated_len < bytes_to_return) {
538 short blocklen = 0;
539 /*
540 * 10.4.2 step 13.1: the truncation of the key length is
541 * implicit as the key is only drbg_blocklen in size based on
542 * the implementation of the cipher function callback
543 */
544 ret = drbg_kcapi_sym(drbg, temp, X, &cipherin);
545 if (ret)
546 goto out;
547 blocklen = (drbg_blocklen(drbg) <
548 (bytes_to_return - generated_len)) ?
549 drbg_blocklen(drbg) :
550 (bytes_to_return - generated_len);
551 /* 10.4.2 step 13.2 and 14 */
552 memcpy(df_data + generated_len, X, blocklen);
553 generated_len += blocklen;
554 }
555
556 ret = 0;
557
558out:
559 memset(iv, 0, drbg_blocklen(drbg));
560 memset(temp, 0, drbg_statelen(drbg));
561 memset(pad, 0, drbg_blocklen(drbg));
562 return ret;
563}
564
565/*
566 * update function of CTR DRBG as defined in 10.2.1.2
567 *
568 * The reseed variable has an enhanced meaning compared to the update
569 * functions of the other DRBGs as follows:
570 * 0 => initial seed from initialization
571 * 1 => reseed via drbg_seed
572 * 2 => first invocation from drbg_ctr_update when addtl is present. In
573 * this case, the df_data scratchpad is not deleted so that it is
574 * available for another calls to prevent calling the DF function
575 * again.
576 * 3 => second invocation from drbg_ctr_update. When the update function
577 * was called with addtl, the df_data memory already contains the
578 * DFed addtl information and we do not need to call DF again.
579 */
580static int drbg_ctr_update(struct drbg_state *drbg, struct list_head *seed,
581 int reseed)
582{
583 int ret = -EFAULT;
584 /* 10.2.1.2 step 1 */
585 unsigned char *temp = drbg->scratchpad;
586 unsigned char *df_data = drbg->scratchpad + drbg_statelen(drbg) +
587 drbg_blocklen(drbg);
588 unsigned char *temp_p, *df_data_p; /* pointer to iterate over buffers */
589 unsigned int len = 0;
590 struct drbg_string cipherin;
591 unsigned char prefix = DRBG_PREFIX1;
592
593 memset(temp, 0, drbg_statelen(drbg) + drbg_blocklen(drbg));
594 if (3 > reseed)
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 (seed) {
599 ret = drbg_ctr_df(drbg, df_data, drbg_statelen(drbg), seed);
600 if (ret)
601 goto out;
602 }
603
604 drbg_string_fill(&cipherin, drbg->V, drbg_blocklen(drbg));
605 /*
606 * 10.2.1.3.2 steps 2 and 3 are already covered as the allocation
607 * zeroizes all memory during initialization
608 */
609 while (len < (drbg_statelen(drbg))) {
610 /* 10.2.1.2 step 2.1 */
611 drbg_add_buf(drbg->V, drbg_blocklen(drbg), &prefix, 1);
612 /*
613 * 10.2.1.2 step 2.2 */
614 ret = drbg_kcapi_sym(drbg, drbg->C, temp + len, &cipherin);
615 if (ret)
616 goto out;
617 /* 10.2.1.2 step 2.3 and 3 */
618 len += drbg_blocklen(drbg);
619 }
620
621 /* 10.2.1.2 step 4 */
622 temp_p = temp;
623 df_data_p = df_data;
624 for (len = 0; len < drbg_statelen(drbg); len++) {
625 *temp_p ^= *df_data_p;
626 df_data_p++; temp_p++;
627 }
628
629 /* 10.2.1.2 step 5 */
630 memcpy(drbg->C, temp, drbg_keylen(drbg));
631 /* 10.2.1.2 step 6 */
632 memcpy(drbg->V, temp + drbg_keylen(drbg), drbg_blocklen(drbg));
633 ret = 0;
634
635out:
636 memset(temp, 0, drbg_statelen(drbg) + drbg_blocklen(drbg));
637 if (2 != reseed)
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 list_head *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 && !list_empty(addtl)) {
660 ret = drbg_ctr_update(drbg, addtl, 2);
661 if (ret)
662 return 0;
663 }
664
665 /* 10.2.1.5.2 step 4.1 */
666 drbg_add_buf(drbg->V, drbg_blocklen(drbg), &prefix, 1);
667 drbg_string_fill(&data, drbg->V, drbg_blocklen(drbg));
668 while (len < buflen) {
669 int outlen = 0;
670 /* 10.2.1.5.2 step 4.2 */
671 ret = drbg_kcapi_sym(drbg, drbg->C, drbg->scratchpad, &data);
672 if (ret) {
673 len = ret;
674 goto out;
675 }
676 outlen = (drbg_blocklen(drbg) < (buflen - len)) ?
677 drbg_blocklen(drbg) : (buflen - len);
678 if (!drbg_fips_continuous_test(drbg, drbg->scratchpad)) {
679 /* 10.2.1.5.2 step 6 */
680 drbg_add_buf(drbg->V, drbg_blocklen(drbg), &prefix, 1);
681 continue;
682 }
683 /* 10.2.1.5.2 step 4.3 */
684 memcpy(buf + len, drbg->scratchpad, outlen);
685 len += outlen;
686 /* 10.2.1.5.2 step 6 */
687 if (len < buflen)
688 drbg_add_buf(drbg->V, drbg_blocklen(drbg), &prefix, 1);
689 }
690
691 /* 10.2.1.5.2 step 6 */
692 ret = drbg_ctr_update(drbg, NULL, 3);
693 if (ret)
694 len = ret;
695
696out:
697 memset(drbg->scratchpad, 0, drbg_blocklen(drbg));
698 return len;
699}
700
701static struct drbg_state_ops drbg_ctr_ops = {
702 .update = drbg_ctr_update,
703 .generate = drbg_ctr_generate,
704 .crypto_init = drbg_init_sym_kernel,
705 .crypto_fini = drbg_fini_sym_kernel,
706};
707#endif /* CONFIG_CRYPTO_DRBG_CTR */
708
709/******************************************************************
710 * HMAC DRBG callback functions
711 ******************************************************************/
712
713#if defined(CONFIG_CRYPTO_DRBG_HASH) || defined(CONFIG_CRYPTO_DRBG_HMAC)
714static int drbg_kcapi_hash(struct drbg_state *drbg, const unsigned char *key,
715 unsigned char *outval, const struct list_head *in);
716static int drbg_init_hash_kernel(struct drbg_state *drbg);
717static int drbg_fini_hash_kernel(struct drbg_state *drbg);
718#endif /* (CONFIG_CRYPTO_DRBG_HASH || CONFIG_CRYPTO_DRBG_HMAC) */
719
720#ifdef CONFIG_CRYPTO_DRBG_HMAC
721#define CRYPTO_DRBG_HMAC_STRING "HMAC "
722/* update function of HMAC DRBG as defined in 10.1.2.2 */
723static int drbg_hmac_update(struct drbg_state *drbg, struct list_head *seed,
724 int reseed)
725{
726 int ret = -EFAULT;
727 int i = 0;
728 struct drbg_string seed1, seed2, vdata;
729 LIST_HEAD(seedlist);
730 LIST_HEAD(vdatalist);
731
732 if (!reseed) {
733 /* 10.1.2.3 step 2 */
734 memset(drbg->C, 0, drbg_statelen(drbg));
735 memset(drbg->V, 1, drbg_statelen(drbg));
736 }
737
738 drbg_string_fill(&seed1, drbg->V, drbg_statelen(drbg));
739 list_add_tail(&seed1.list, &seedlist);
740 /* buffer of seed2 will be filled in for loop below with one byte */
741 drbg_string_fill(&seed2, NULL, 1);
742 list_add_tail(&seed2.list, &seedlist);
743 /* input data of seed is allowed to be NULL at this point */
744 if (seed)
745 list_splice_tail(seed, &seedlist);
746
747 drbg_string_fill(&vdata, drbg->V, drbg_statelen(drbg));
748 list_add_tail(&vdata.list, &vdatalist);
749 for (i = 2; 0 < i; i--) {
750 /* first round uses 0x0, second 0x1 */
751 unsigned char prefix = DRBG_PREFIX0;
752 if (1 == i)
753 prefix = DRBG_PREFIX1;
754 /* 10.1.2.2 step 1 and 4 -- concatenation and HMAC for key */
755 seed2.buf = &prefix;
756 ret = drbg_kcapi_hash(drbg, drbg->C, drbg->C, &seedlist);
757 if (ret)
758 return ret;
759
760 /* 10.1.2.2 step 2 and 5 -- HMAC for V */
761 ret = drbg_kcapi_hash(drbg, drbg->C, drbg->V, &vdatalist);
762 if (ret)
763 return ret;
764
765 /* 10.1.2.2 step 3 */
766 if (!seed)
767 return ret;
768 }
769
770 return 0;
771}
772
773/* generate function of HMAC DRBG as defined in 10.1.2.5 */
774static int drbg_hmac_generate(struct drbg_state *drbg,
775 unsigned char *buf,
776 unsigned int buflen,
777 struct list_head *addtl)
778{
779 int len = 0;
780 int ret = 0;
781 struct drbg_string data;
782 LIST_HEAD(datalist);
783
784 /* 10.1.2.5 step 2 */
785 if (addtl && !list_empty(addtl)) {
786 ret = drbg_hmac_update(drbg, addtl, 1);
787 if (ret)
788 return ret;
789 }
790
791 drbg_string_fill(&data, drbg->V, drbg_statelen(drbg));
792 list_add_tail(&data.list, &datalist);
793 while (len < buflen) {
794 unsigned int outlen = 0;
795 /* 10.1.2.5 step 4.1 */
796 ret = drbg_kcapi_hash(drbg, drbg->C, drbg->V, &datalist);
797 if (ret)
798 return ret;
799 outlen = (drbg_blocklen(drbg) < (buflen - len)) ?
800 drbg_blocklen(drbg) : (buflen - len);
801 if (!drbg_fips_continuous_test(drbg, drbg->V))
802 continue;
803
804 /* 10.1.2.5 step 4.2 */
805 memcpy(buf + len, drbg->V, outlen);
806 len += outlen;
807 }
808
809 /* 10.1.2.5 step 6 */
810 if (addtl && !list_empty(addtl))
811 ret = drbg_hmac_update(drbg, addtl, 1);
812 else
813 ret = drbg_hmac_update(drbg, NULL, 1);
814 if (ret)
815 return ret;
816
817 return len;
818}
819
820static struct drbg_state_ops drbg_hmac_ops = {
821 .update = drbg_hmac_update,
822 .generate = drbg_hmac_generate,
823 .crypto_init = drbg_init_hash_kernel,
824 .crypto_fini = drbg_fini_hash_kernel,
825
826};
827#endif /* CONFIG_CRYPTO_DRBG_HMAC */
828
829/******************************************************************
830 * Hash DRBG callback functions
831 ******************************************************************/
832
833#ifdef CONFIG_CRYPTO_DRBG_HASH
834#define CRYPTO_DRBG_HASH_STRING "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 list_head *entropylist)
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 data;
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(&data, input, 5);
869 list_add(&data.list, entropylist);
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, entropylist);
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 list_head *seed,
893 int reseed)
894{
895 int ret = 0;
896 struct drbg_string data1, data2;
897 LIST_HEAD(datalist);
898 LIST_HEAD(datalist2);
899 unsigned char *V = drbg->scratchpad;
900 unsigned char prefix = DRBG_PREFIX1;
901
902 memset(drbg->scratchpad, 0, drbg_statelen(drbg));
903 if (!seed)
904 return -EINVAL;
905
906 if (reseed) {
907 /* 10.1.1.3 step 1 */
908 memcpy(V, drbg->V, drbg_statelen(drbg));
909 drbg_string_fill(&data1, &prefix, 1);
910 list_add_tail(&data1.list, &datalist);
911 drbg_string_fill(&data2, V, drbg_statelen(drbg));
912 list_add_tail(&data2.list, &datalist);
913 }
914 list_splice_tail(seed, &datalist);
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), &datalist);
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 list_add_tail(&data1.list, &datalist2);
925 drbg_string_fill(&data2, drbg->V, drbg_statelen(drbg));
926 list_add_tail(&data2.list, &datalist2);
927 /* 10.1.1.2 / 10.1.1.3 step 4 */
928 ret = drbg_hash_df(drbg, drbg->C, drbg_statelen(drbg), &datalist2);
929
930out:
931 memset(drbg->scratchpad, 0, drbg_statelen(drbg));
932 return ret;
933}
934
935/* processing of additional information string for Hash DRBG */
936static int drbg_hash_process_addtl(struct drbg_state *drbg,
937 struct list_head *addtl)
938{
939 int ret = 0;
940 struct drbg_string data1, data2;
941 LIST_HEAD(datalist);
942 unsigned char prefix = DRBG_PREFIX2;
943
944 /* this is value w as per documentation */
945 memset(drbg->scratchpad, 0, drbg_blocklen(drbg));
946
947 /* 10.1.1.4 step 2 */
948 if (!addtl || list_empty(addtl))
949 return 0;
950
951 /* 10.1.1.4 step 2a */
952 drbg_string_fill(&data1, &prefix, 1);
953 drbg_string_fill(&data2, drbg->V, drbg_statelen(drbg));
954 list_add_tail(&data1.list, &datalist);
955 list_add_tail(&data2.list, &datalist);
956 list_splice_tail(addtl, &datalist);
957 ret = drbg_kcapi_hash(drbg, NULL, drbg->scratchpad, &datalist);
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 LIST_HEAD(datalist);
981 unsigned char prefix = DRBG_PREFIX1;
982
983 memset(src, 0, drbg_statelen(drbg));
984 memset(dst, 0, drbg_blocklen(drbg));
985
986 /* 10.1.1.4 step hashgen 2 */
987 memcpy(src, drbg->V, drbg_statelen(drbg));
988
989 drbg_string_fill(&data, src, drbg_statelen(drbg));
990 list_add_tail(&data.list, &datalist);
991 while (len < buflen) {
992 unsigned int outlen = 0;
993 /* 10.1.1.4 step hashgen 4.1 */
994 ret = drbg_kcapi_hash(drbg, NULL, dst, &datalist);
995 if (ret) {
996 len = ret;
997 goto out;
998 }
999 outlen = (drbg_blocklen(drbg) < (buflen - len)) ?
1000 drbg_blocklen(drbg) : (buflen - len);
1001 if (!drbg_fips_continuous_test(drbg, dst)) {
1002 drbg_add_buf(src, drbg_statelen(drbg), &prefix, 1);
1003 continue;
1004 }
1005 /* 10.1.1.4 step hashgen 4.2 */
1006 memcpy(buf + len, dst, outlen);
1007 len += outlen;
1008 /* 10.1.1.4 hashgen step 4.3 */
1009 if (len < buflen)
1010 drbg_add_buf(src, drbg_statelen(drbg), &prefix, 1);
1011 }
1012
1013out:
1014 memset(drbg->scratchpad, 0,
1015 (drbg_statelen(drbg) + drbg_blocklen(drbg)));
1016 return len;
1017}
1018
1019/* generate function for Hash DRBG as defined in 10.1.1.4 */
1020static int drbg_hash_generate(struct drbg_state *drbg,
1021 unsigned char *buf, unsigned int buflen,
1022 struct list_head *addtl)
1023{
1024 int len = 0;
1025 int ret = 0;
1026 unsigned char req[8];
1027 unsigned char prefix = DRBG_PREFIX3;
1028 struct drbg_string data1, data2;
1029 LIST_HEAD(datalist);
1030
1031 /* 10.1.1.4 step 2 */
1032 ret = drbg_hash_process_addtl(drbg, addtl);
1033 if (ret)
1034 return ret;
1035 /* 10.1.1.4 step 3 */
1036 len = drbg_hash_hashgen(drbg, buf, buflen);
1037
1038 /* this is the value H as documented in 10.1.1.4 */
1039 memset(drbg->scratchpad, 0, drbg_blocklen(drbg));
1040 /* 10.1.1.4 step 4 */
1041 drbg_string_fill(&data1, &prefix, 1);
1042 list_add_tail(&data1.list, &datalist);
1043 drbg_string_fill(&data2, drbg->V, drbg_statelen(drbg));
1044 list_add_tail(&data2.list, &datalist);
1045 ret = drbg_kcapi_hash(drbg, NULL, drbg->scratchpad, &datalist);
1046 if (ret) {
1047 len = ret;
1048 goto out;
1049 }
1050
1051 /* 10.1.1.4 step 5 */
1052 drbg_add_buf(drbg->V, drbg_statelen(drbg),
1053 drbg->scratchpad, drbg_blocklen(drbg));
1054 drbg_add_buf(drbg->V, drbg_statelen(drbg),
1055 drbg->C, drbg_statelen(drbg));
1056 drbg_int2byte(req, drbg->reseed_ctr, sizeof(req));
1057 drbg_add_buf(drbg->V, drbg_statelen(drbg), req, 8);
1058
1059out:
1060 memset(drbg->scratchpad, 0, drbg_blocklen(drbg));
1061 return len;
1062}
1063
1064/*
1065 * scratchpad usage: as update and generate are used isolated, both
1066 * can use the scratchpad
1067 */
1068static struct drbg_state_ops drbg_hash_ops = {
1069 .update = drbg_hash_update,
1070 .generate = drbg_hash_generate,
1071 .crypto_init = drbg_init_hash_kernel,
1072 .crypto_fini = drbg_fini_hash_kernel,
1073};
1074#endif /* CONFIG_CRYPTO_DRBG_HASH */
1075
1076/******************************************************************
1077 * Functions common for DRBG implementations
1078 ******************************************************************/
1079
1080/*
1081 * Seeding or reseeding of the DRBG
1082 *
1083 * @drbg: DRBG state struct
1084 * @pers: personalization / additional information buffer
1085 * @reseed: 0 for initial seed process, 1 for reseeding
1086 *
1087 * return:
1088 * 0 on success
1089 * error value otherwise
1090 */
1091static int drbg_seed(struct drbg_state *drbg, struct drbg_string *pers,
1092 bool reseed)
1093{
1094 int ret = 0;
1095 unsigned char *entropy = NULL;
1096 size_t entropylen = 0;
1097 struct drbg_string data1;
1098 LIST_HEAD(seedlist);
1099
1100 /* 9.1 / 9.2 / 9.3.1 step 3 */
1101 if (pers && pers->len > (drbg_max_addtl(drbg))) {
1102 pr_devel("DRBG: personalization string too long %zu\n",
1103 pers->len);
1104 return -EINVAL;
1105 }
1106
1107 if (drbg->test_data && drbg->test_data->testentropy) {
1108 drbg_string_fill(&data1, drbg->test_data->testentropy->buf,
1109 drbg->test_data->testentropy->len);
1110 pr_devel("DRBG: using test entropy\n");
1111 } else {
1112 /*
1113 * Gather entropy equal to the security strength of the DRBG.
1114 * With a derivation function, a nonce is required in addition
1115 * to the entropy. A nonce must be at least 1/2 of the security
1116 * strength of the DRBG in size. Thus, entropy * nonce is 3/2
1117 * of the strength. The consideration of a nonce is only
1118 * applicable during initial seeding.
1119 */
1120 entropylen = drbg_sec_strength(drbg->core->flags);
1121 if (!entropylen)
1122 return -EFAULT;
1123 if (!reseed)
1124 entropylen = ((entropylen + 1) / 2) * 3;
1125 pr_devel("DRBG: (re)seeding with %zu bytes of entropy\n",
1126 entropylen);
1127 entropy = kzalloc(entropylen, GFP_KERNEL);
1128 if (!entropy)
1129 return -ENOMEM;
1130 get_random_bytes(entropy, entropylen);
1131 drbg_string_fill(&data1, entropy, entropylen);
1132 }
1133 list_add_tail(&data1.list, &seedlist);
1134
1135 /*
1136 * concatenation of entropy with personalization str / addtl input)
1137 * the variable pers is directly handed in by the caller, so check its
1138 * contents whether it is appropriate
1139 */
1140 if (pers && pers->buf && 0 < pers->len) {
1141 list_add_tail(&pers->list, &seedlist);
1142 pr_devel("DRBG: using personalization string\n");
1143 }
1144
1145 ret = drbg->d_ops->update(drbg, &seedlist, reseed);
1146 if (ret)
1147 goto out;
1148
1149 drbg->seeded = true;
1150 /* 10.1.1.2 / 10.1.1.3 step 5 */
1151 drbg->reseed_ctr = 1;
1152
1153out:
1154 if (entropy)
1155 kzfree(entropy);
1156 return ret;
1157}
1158
1159/* Free all substructures in a DRBG state without the DRBG state structure */
1160static inline void drbg_dealloc_state(struct drbg_state *drbg)
1161{
1162 if (!drbg)
1163 return;
1164 if (drbg->V)
1165 kzfree(drbg->V);
1166 drbg->V = NULL;
1167 if (drbg->C)
1168 kzfree(drbg->C);
1169 drbg->C = NULL;
1170 if (drbg->scratchpad)
1171 kzfree(drbg->scratchpad);
1172 drbg->scratchpad = NULL;
1173 drbg->reseed_ctr = 0;
1174#ifdef CONFIG_CRYPTO_FIPS
1175 if (drbg->prev)
1176 kzfree(drbg->prev);
1177 drbg->prev = NULL;
1178 drbg->fips_primed = false;
1179#endif
1180}
1181
1182/*
1183 * Allocate all sub-structures for a DRBG state.
1184 * The DRBG state structure must already be allocated.
1185 */
1186static inline int drbg_alloc_state(struct drbg_state *drbg)
1187{
1188 int ret = -ENOMEM;
1189 unsigned int sb_size = 0;
1190
1191 if (!drbg)
1192 return -EINVAL;
1193
1194 drbg->V = kzalloc(drbg_statelen(drbg), GFP_KERNEL);
1195 if (!drbg->V)
1196 goto err;
1197 drbg->C = kzalloc(drbg_statelen(drbg), GFP_KERNEL);
1198 if (!drbg->C)
1199 goto err;
1200#ifdef CONFIG_CRYPTO_FIPS
1201 drbg->prev = kzalloc(drbg_blocklen(drbg), GFP_KERNEL);
1202 if (!drbg->prev)
1203 goto err;
1204 drbg->fips_primed = false;
1205#endif
1206 /* scratchpad is only generated for CTR and Hash */
1207 if (drbg->core->flags & DRBG_HMAC)
1208 sb_size = 0;
1209 else if (drbg->core->flags & DRBG_CTR)
1210 sb_size = drbg_statelen(drbg) + drbg_blocklen(drbg) + /* temp */
1211 drbg_statelen(drbg) + /* df_data */
1212 drbg_blocklen(drbg) + /* pad */
1213 drbg_blocklen(drbg) + /* iv */
1214 drbg_statelen(drbg) + drbg_blocklen(drbg); /* temp */
1215 else
1216 sb_size = drbg_statelen(drbg) + drbg_blocklen(drbg);
1217
1218 if (0 < sb_size) {
1219 drbg->scratchpad = kzalloc(sb_size, GFP_KERNEL);
1220 if (!drbg->scratchpad)
1221 goto err;
1222 }
1223 spin_lock_init(&drbg->drbg_lock);
1224 return 0;
1225
1226err:
1227 drbg_dealloc_state(drbg);
1228 return ret;
1229}
1230
1231/*
1232 * Strategy to avoid holding long term locks: generate a shadow copy of DRBG
1233 * and perform all operations on this shadow copy. After finishing, restore
1234 * the updated state of the shadow copy into original drbg state. This way,
1235 * only the read and write operations of the original drbg state must be
1236 * locked
1237 */
1238static inline void drbg_copy_drbg(struct drbg_state *src,
1239 struct drbg_state *dst)
1240{
1241 if (!src || !dst)
1242 return;
1243 memcpy(dst->V, src->V, drbg_statelen(src));
1244 memcpy(dst->C, src->C, drbg_statelen(src));
1245 dst->reseed_ctr = src->reseed_ctr;
1246 dst->seeded = src->seeded;
1247 dst->pr = src->pr;
1248#ifdef CONFIG_CRYPTO_FIPS
1249 dst->fips_primed = src->fips_primed;
1250 memcpy(dst->prev, src->prev, drbg_blocklen(src));
1251#endif
1252 /*
1253 * Not copied:
1254 * scratchpad is initialized drbg_alloc_state;
1255 * priv_data is initialized with call to crypto_init;
1256 * d_ops and core are set outside, as these parameters are const;
1257 * test_data is set outside to prevent it being copied back.
1258 */
1259}
1260
1261static int drbg_make_shadow(struct drbg_state *drbg, struct drbg_state **shadow)
1262{
1263 int ret = -ENOMEM;
1264 struct drbg_state *tmp = NULL;
1265
1266 if (!drbg || !drbg->core || !drbg->V || !drbg->C) {
1267 pr_devel("DRBG: attempt to generate shadow copy for "
1268 "uninitialized DRBG state rejected\n");
1269 return -EINVAL;
1270 }
1271 /* HMAC does not have a scratchpad */
1272 if (!(drbg->core->flags & DRBG_HMAC) && NULL == drbg->scratchpad)
1273 return -EINVAL;
1274
1275 tmp = kzalloc(sizeof(struct drbg_state), GFP_KERNEL);
1276 if (!tmp)
1277 return -ENOMEM;
1278
1279 /* read-only data as they are defined as const, no lock needed */
1280 tmp->core = drbg->core;
1281 tmp->d_ops = drbg->d_ops;
1282
1283 ret = drbg_alloc_state(tmp);
1284 if (ret)
1285 goto err;
1286
1287 spin_lock_bh(&drbg->drbg_lock);
1288 drbg_copy_drbg(drbg, tmp);
1289 /* only make a link to the test buffer, as we only read that data */
1290 tmp->test_data = drbg->test_data;
1291 spin_unlock_bh(&drbg->drbg_lock);
1292 *shadow = tmp;
1293 return 0;
1294
1295err:
1296 if (tmp)
1297 kzfree(tmp);
1298 return ret;
1299}
1300
1301static void drbg_restore_shadow(struct drbg_state *drbg,
1302 struct drbg_state **shadow)
1303{
1304 struct drbg_state *tmp = *shadow;
1305
1306 spin_lock_bh(&drbg->drbg_lock);
1307 drbg_copy_drbg(tmp, drbg);
1308 spin_unlock_bh(&drbg->drbg_lock);
1309 drbg_dealloc_state(tmp);
1310 kzfree(tmp);
1311 *shadow = NULL;
1312}
1313
1314/*************************************************************************
1315 * DRBG interface functions
1316 *************************************************************************/
1317
1318/*
1319 * DRBG generate function as required by SP800-90A - this function
1320 * generates random numbers
1321 *
1322 * @drbg DRBG state handle
1323 * @buf Buffer where to store the random numbers -- the buffer must already
1324 * be pre-allocated by caller
1325 * @buflen Length of output buffer - this value defines the number of random
1326 * bytes pulled from DRBG
1327 * @addtl Additional input that is mixed into state, may be NULL -- note
1328 * the entropy is pulled by the DRBG internally unconditionally
1329 * as defined in SP800-90A. The additional input is mixed into
1330 * the state in addition to the pulled entropy.
1331 *
1332 * return: generated number of bytes
1333 */
1334static int drbg_generate(struct drbg_state *drbg,
1335 unsigned char *buf, unsigned int buflen,
1336 struct drbg_string *addtl)
1337{
1338 int len = 0;
1339 struct drbg_state *shadow = NULL;
1340 LIST_HEAD(addtllist);
1341 struct drbg_string timestamp;
1342 union {
1343 cycles_t cycles;
1344 unsigned char char_cycles[sizeof(cycles_t)];
1345 } now;
1346
1347 if (0 == buflen || !buf) {
1348 pr_devel("DRBG: no output buffer provided\n");
1349 return -EINVAL;
1350 }
1351 if (addtl && NULL == addtl->buf && 0 < addtl->len) {
1352 pr_devel("DRBG: wrong format of additional information\n");
1353 return -EINVAL;
1354 }
1355
1356 len = drbg_make_shadow(drbg, &shadow);
1357 if (len) {
1358 pr_devel("DRBG: shadow copy cannot be generated\n");
1359 return len;
1360 }
1361
1362 /* 9.3.1 step 2 */
1363 len = -EINVAL;
1364 if (buflen > (drbg_max_request_bytes(shadow))) {
1365 pr_devel("DRBG: requested random numbers too large %u\n",
1366 buflen);
1367 goto err;
1368 }
1369
1370 /* 9.3.1 step 3 is implicit with the chosen DRBG */
1371
1372 /* 9.3.1 step 4 */
1373 if (addtl && addtl->len > (drbg_max_addtl(shadow))) {
1374 pr_devel("DRBG: additional information string too long %zu\n",
1375 addtl->len);
1376 goto err;
1377 }
1378 /* 9.3.1 step 5 is implicit with the chosen DRBG */
1379
1380 /*
1381 * 9.3.1 step 6 and 9 supplemented by 9.3.2 step c is implemented
1382 * here. The spec is a bit convoluted here, we make it simpler.
1383 */
1384 if ((drbg_max_requests(shadow)) < shadow->reseed_ctr)
1385 shadow->seeded = false;
1386
1387 /* allocate cipher handle */
1388 if (shadow->d_ops->crypto_init) {
1389 len = shadow->d_ops->crypto_init(shadow);
1390 if (len)
1391 goto err;
1392 }
1393
1394 if (shadow->pr || !shadow->seeded) {
1395 pr_devel("DRBG: reseeding before generation (prediction "
1396 "resistance: %s, state %s)\n",
1397 drbg->pr ? "true" : "false",
1398 drbg->seeded ? "seeded" : "unseeded");
1399 /* 9.3.1 steps 7.1 through 7.3 */
1400 len = drbg_seed(shadow, addtl, true);
1401 if (len)
1402 goto err;
1403 /* 9.3.1 step 7.4 */
1404 addtl = NULL;
1405 }
1406
1407 /*
1408 * Mix the time stamp into the DRBG state if the DRBG is not in
1409 * test mode. If there are two callers invoking the DRBG at the same
1410 * time, i.e. before the first caller merges its shadow state back,
1411 * both callers would obtain the same random number stream without
1412 * changing the state here.
1413 */
1414 if (!drbg->test_data) {
1415 now.cycles = random_get_entropy();
1416 drbg_string_fill(&timestamp, now.char_cycles, sizeof(cycles_t));
1417 list_add_tail(&timestamp.list, &addtllist);
1418 }
1419 if (addtl && 0 < addtl->len)
1420 list_add_tail(&addtl->list, &addtllist);
1421 /* 9.3.1 step 8 and 10 */
1422 len = shadow->d_ops->generate(shadow, buf, buflen, &addtllist);
1423
1424 /* 10.1.1.4 step 6, 10.1.2.5 step 7, 10.2.1.5.2 step 7 */
1425 shadow->reseed_ctr++;
1426 if (0 >= len)
1427 goto err;
1428
1429 /*
1430 * Section 11.3.3 requires to re-perform self tests after some
1431 * generated random numbers. The chosen value after which self
1432 * test is performed is arbitrary, but it should be reasonable.
1433 * However, we do not perform the self tests because of the following
1434 * reasons: it is mathematically impossible that the initial self tests
1435 * were successfully and the following are not. If the initial would
1436 * pass and the following would not, the kernel integrity is violated.
1437 * In this case, the entire kernel operation is questionable and it
1438 * is unlikely that the integrity violation only affects the
1439 * correct operation of the DRBG.
1440 *
1441 * Albeit the following code is commented out, it is provided in
1442 * case somebody has a need to implement the test of 11.3.3.
1443 */
1444#if 0
1445 if (shadow->reseed_ctr && !(shadow->reseed_ctr % 4096)) {
1446 int err = 0;
1447 pr_devel("DRBG: start to perform self test\n");
1448 if (drbg->core->flags & DRBG_HMAC)
1449 err = alg_test("drbg_pr_hmac_sha256",
1450 "drbg_pr_hmac_sha256", 0, 0);
1451 else if (drbg->core->flags & DRBG_CTR)
1452 err = alg_test("drbg_pr_ctr_aes128",
1453 "drbg_pr_ctr_aes128", 0, 0);
1454 else
1455 err = alg_test("drbg_pr_sha256",
1456 "drbg_pr_sha256", 0, 0);
1457 if (err) {
1458 pr_err("DRBG: periodical self test failed\n");
1459 /*
1460 * uninstantiate implies that from now on, only errors
1461 * are returned when reusing this DRBG cipher handle
1462 */
1463 drbg_uninstantiate(drbg);
1464 drbg_dealloc_state(shadow);
1465 kzfree(shadow);
1466 return 0;
1467 } else {
1468 pr_devel("DRBG: self test successful\n");
1469 }
1470 }
1471#endif
1472
1473err:
1474 if (shadow->d_ops->crypto_fini)
1475 shadow->d_ops->crypto_fini(shadow);
1476 drbg_restore_shadow(drbg, &shadow);
1477 return len;
1478}
1479
1480/*
1481 * Wrapper around drbg_generate which can pull arbitrary long strings
1482 * from the DRBG without hitting the maximum request limitation.
1483 *
1484 * Parameters: see drbg_generate
1485 * Return codes: see drbg_generate -- if one drbg_generate request fails,
1486 * the entire drbg_generate_long request fails
1487 */
1488static int drbg_generate_long(struct drbg_state *drbg,
1489 unsigned char *buf, unsigned int buflen,
1490 struct drbg_string *addtl)
1491{
1492 int len = 0;
1493 unsigned int slice = 0;
1494 do {
1495 int tmplen = 0;
1496 unsigned int chunk = 0;
1497 slice = ((buflen - len) / drbg_max_request_bytes(drbg));
1498 chunk = slice ? drbg_max_request_bytes(drbg) : (buflen - len);
1499 tmplen = drbg_generate(drbg, buf + len, chunk, addtl);
1500 if (0 >= tmplen)
1501 return tmplen;
1502 len += tmplen;
1503 } while (slice > 0 && (len < buflen));
1504 return len;
1505}
1506
1507/*
1508 * DRBG instantiation function as required by SP800-90A - this function
1509 * sets up the DRBG handle, performs the initial seeding and all sanity
1510 * checks required by SP800-90A
1511 *
1512 * @drbg memory of state -- if NULL, new memory is allocated
1513 * @pers Personalization string that is mixed into state, may be NULL -- note
1514 * the entropy is pulled by the DRBG internally unconditionally
1515 * as defined in SP800-90A. The additional input is mixed into
1516 * the state in addition to the pulled entropy.
1517 * @coreref reference to core
1518 * @pr prediction resistance enabled
1519 *
1520 * return
1521 * 0 on success
1522 * error value otherwise
1523 */
1524static int drbg_instantiate(struct drbg_state *drbg, struct drbg_string *pers,
1525 int coreref, bool pr)
1526{
1527 int ret = -ENOMEM;
1528
1529 pr_devel("DRBG: Initializing DRBG core %d with prediction resistance "
1530 "%s\n", coreref, pr ? "enabled" : "disabled");
1531 drbg->core = &drbg_cores[coreref];
1532 drbg->pr = pr;
1533 drbg->seeded = false;
1534 switch (drbg->core->flags & DRBG_TYPE_MASK) {
1535#ifdef CONFIG_CRYPTO_DRBG_HMAC
1536 case DRBG_HMAC:
1537 drbg->d_ops = &drbg_hmac_ops;
1538 break;
1539#endif /* CONFIG_CRYPTO_DRBG_HMAC */
1540#ifdef CONFIG_CRYPTO_DRBG_HASH
1541 case DRBG_HASH:
1542 drbg->d_ops = &drbg_hash_ops;
1543 break;
1544#endif /* CONFIG_CRYPTO_DRBG_HASH */
1545#ifdef CONFIG_CRYPTO_DRBG_CTR
1546 case DRBG_CTR:
1547 drbg->d_ops = &drbg_ctr_ops;
1548 break;
1549#endif /* CONFIG_CRYPTO_DRBG_CTR */
1550 default:
1551 return -EOPNOTSUPP;
1552 }
1553
1554 /* 9.1 step 1 is implicit with the selected DRBG type */
1555
1556 /*
1557 * 9.1 step 2 is implicit as caller can select prediction resistance
1558 * and the flag is copied into drbg->flags --
1559 * all DRBG types support prediction resistance
1560 */
1561
1562 /* 9.1 step 4 is implicit in drbg_sec_strength */
1563
1564 ret = drbg_alloc_state(drbg);
1565 if (ret)
1566 return ret;
1567
1568 ret = -EFAULT;
1569 if (drbg->d_ops->crypto_init && drbg->d_ops->crypto_init(drbg))
1570 goto err;
1571 ret = drbg_seed(drbg, pers, false);
1572 if (drbg->d_ops->crypto_fini)
1573 drbg->d_ops->crypto_fini(drbg);
1574 if (ret)
1575 goto err;
1576
1577 return 0;
1578
1579err:
1580 drbg_dealloc_state(drbg);
1581 return ret;
1582}
1583
1584/*
1585 * DRBG uninstantiate function as required by SP800-90A - this function
1586 * frees all buffers and the DRBG handle
1587 *
1588 * @drbg DRBG state handle
1589 *
1590 * return
1591 * 0 on success
1592 */
1593static int drbg_uninstantiate(struct drbg_state *drbg)
1594{
1595 spin_lock_bh(&drbg->drbg_lock);
1596 drbg_dealloc_state(drbg);
1597 /* no scrubbing of test_data -- this shall survive an uninstantiate */
1598 spin_unlock_bh(&drbg->drbg_lock);
1599 return 0;
1600}
1601
1602/*
1603 * Helper function for setting the test data in the DRBG
1604 *
1605 * @drbg DRBG state handle
1606 * @test_data test data to sets
1607 */
1608static inline void drbg_set_testdata(struct drbg_state *drbg,
1609 struct drbg_test_data *test_data)
1610{
1611 if (!test_data || !test_data->testentropy)
1612 return;
1613 spin_lock_bh(&drbg->drbg_lock);
1614 drbg->test_data = test_data;
1615 spin_unlock_bh(&drbg->drbg_lock);
1616}
1617
1618/***************************************************************
1619 * Kernel crypto API cipher invocations requested by DRBG
1620 ***************************************************************/
1621
1622#if defined(CONFIG_CRYPTO_DRBG_HASH) || defined(CONFIG_CRYPTO_DRBG_HMAC)
1623struct sdesc {
1624 struct shash_desc shash;
1625 char ctx[];
1626};
1627
1628static int drbg_init_hash_kernel(struct drbg_state *drbg)
1629{
1630 struct sdesc *sdesc;
1631 struct crypto_shash *tfm;
1632
1633 tfm = crypto_alloc_shash(drbg->core->backend_cra_name, 0, 0);
1634 if (IS_ERR(tfm)) {
1635 pr_info("DRBG: could not allocate digest TFM handle\n");
1636 return PTR_ERR(tfm);
1637 }
1638 BUG_ON(drbg_blocklen(drbg) != crypto_shash_digestsize(tfm));
1639 sdesc = kzalloc(sizeof(struct shash_desc) + crypto_shash_descsize(tfm),
1640 GFP_KERNEL);
1641 if (!sdesc) {
1642 crypto_free_shash(tfm);
1643 return -ENOMEM;
1644 }
1645
1646 sdesc->shash.tfm = tfm;
1647 sdesc->shash.flags = 0;
1648 drbg->priv_data = sdesc;
1649 return 0;
1650}
1651
1652static int drbg_fini_hash_kernel(struct drbg_state *drbg)
1653{
1654 struct sdesc *sdesc = (struct sdesc *)drbg->priv_data;
1655 if (sdesc) {
1656 crypto_free_shash(sdesc->shash.tfm);
1657 kzfree(sdesc);
1658 }
1659 drbg->priv_data = NULL;
1660 return 0;
1661}
1662
1663static int drbg_kcapi_hash(struct drbg_state *drbg, const unsigned char *key,
1664 unsigned char *outval, const struct list_head *in)
1665{
1666 struct sdesc *sdesc = (struct sdesc *)drbg->priv_data;
1667 struct drbg_string *input = NULL;
1668
1669 if (key)
1670 crypto_shash_setkey(sdesc->shash.tfm, key, drbg_statelen(drbg));
1671 crypto_shash_init(&sdesc->shash);
1672 list_for_each_entry(input, in, list)
1673 crypto_shash_update(&sdesc->shash, input->buf, input->len);
1674 return crypto_shash_final(&sdesc->shash, outval);
1675}
1676#endif /* (CONFIG_CRYPTO_DRBG_HASH || CONFIG_CRYPTO_DRBG_HMAC) */
1677
1678#ifdef CONFIG_CRYPTO_DRBG_CTR
1679static int drbg_init_sym_kernel(struct drbg_state *drbg)
1680{
1681 int ret = 0;
1682 struct crypto_blkcipher *tfm;
1683
1684 tfm = crypto_alloc_blkcipher(drbg->core->backend_cra_name, 0, 0);
1685 if (IS_ERR(tfm)) {
1686 pr_info("DRBG: could not allocate cipher TFM handle\n");
1687 return PTR_ERR(tfm);
1688 }
1689 BUG_ON(drbg_blocklen(drbg) != crypto_blkcipher_blocksize(tfm));
1690 drbg->priv_data = tfm;
1691 return ret;
1692}
1693
1694static int drbg_fini_sym_kernel(struct drbg_state *drbg)
1695{
1696 struct crypto_blkcipher *tfm =
1697 (struct crypto_blkcipher *)drbg->priv_data;
1698 if (tfm)
1699 crypto_free_blkcipher(tfm);
1700 drbg->priv_data = NULL;
1701 return 0;
1702}
1703
1704static int drbg_kcapi_sym(struct drbg_state *drbg, const unsigned char *key,
1705 unsigned char *outval, const struct drbg_string *in)
1706{
1707 int ret = 0;
1708 struct scatterlist sg_in, sg_out;
1709 struct blkcipher_desc desc;
1710 struct crypto_blkcipher *tfm =
1711 (struct crypto_blkcipher *)drbg->priv_data;
1712
1713 desc.tfm = tfm;
1714 desc.flags = 0;
1715 crypto_blkcipher_setkey(tfm, key, (drbg_keylen(drbg)));
1716 /* there is only component in *in */
1717 sg_init_one(&sg_in, in->buf, in->len);
1718 sg_init_one(&sg_out, outval, drbg_blocklen(drbg));
1719 ret = crypto_blkcipher_encrypt(&desc, &sg_out, &sg_in, in->len);
1720
1721 return ret;
1722}
1723#endif /* CONFIG_CRYPTO_DRBG_CTR */
1724
1725/***************************************************************
1726 * Kernel crypto API interface to register DRBG
1727 ***************************************************************/
1728
1729/*
1730 * Look up the DRBG flags by given kernel crypto API cra_name
1731 * The code uses the drbg_cores definition to do this
1732 *
1733 * @cra_name kernel crypto API cra_name
1734 * @coreref reference to integer which is filled with the pointer to
1735 * the applicable core
1736 * @pr reference for setting prediction resistance
1737 *
1738 * return: flags
1739 */
1740static inline void drbg_convert_tfm_core(const char *cra_driver_name,
1741 int *coreref, bool *pr)
1742{
1743 int i = 0;
1744 size_t start = 0;
1745 int len = 0;
1746
1747 *pr = true;
1748 /* disassemble the names */
1749 if (!memcmp(cra_driver_name, "drbg_nopr_", 10)) {
1750 start = 10;
1751 *pr = false;
1752 } else if (!memcmp(cra_driver_name, "drbg_pr_", 8)) {
1753 start = 8;
1754 } else {
1755 return;
1756 }
1757
1758 /* remove the first part */
1759 len = strlen(cra_driver_name) - start;
1760 for (i = 0; ARRAY_SIZE(drbg_cores) > i; i++) {
1761 if (!memcmp(cra_driver_name + start, drbg_cores[i].cra_name,
1762 len)) {
1763 *coreref = i;
1764 return;
1765 }
1766 }
1767}
1768
1769static int drbg_kcapi_init(struct crypto_tfm *tfm)
1770{
1771 struct drbg_state *drbg = crypto_tfm_ctx(tfm);
1772 bool pr = false;
1773 int coreref = 0;
1774
1775 drbg_convert_tfm_core(crypto_tfm_alg_driver_name(tfm), &coreref, &pr);
1776 /*
1777 * when personalization string is needed, the caller must call reset
1778 * and provide the personalization string as seed information
1779 */
1780 return drbg_instantiate(drbg, NULL, coreref, pr);
1781}
1782
1783static void drbg_kcapi_cleanup(struct crypto_tfm *tfm)
1784{
1785 drbg_uninstantiate(crypto_tfm_ctx(tfm));
1786}
1787
1788/*
1789 * Generate random numbers invoked by the kernel crypto API:
1790 * The API of the kernel crypto API is extended as follows:
1791 *
1792 * If dlen is larger than zero, rdata is interpreted as the output buffer
1793 * where random data is to be stored.
1794 *
1795 * If dlen is zero, rdata is interpreted as a pointer to a struct drbg_gen
1796 * which holds the additional information string that is used for the
1797 * DRBG generation process. The output buffer that is to be used to store
1798 * data is also pointed to by struct drbg_gen.
1799 */
1800static int drbg_kcapi_random(struct crypto_rng *tfm, u8 *rdata,
1801 unsigned int dlen)
1802{
1803 struct drbg_state *drbg = crypto_rng_ctx(tfm);
1804 if (0 < dlen) {
1805 return drbg_generate_long(drbg, rdata, dlen, NULL);
1806 } else {
1807 struct drbg_gen *data = (struct drbg_gen *)rdata;
1808 struct drbg_string addtl;
1809 /* catch NULL pointer */
1810 if (!data)
1811 return 0;
1812 drbg_set_testdata(drbg, data->test_data);
1813 /* linked list variable is now local to allow modification */
1814 drbg_string_fill(&addtl, data->addtl->buf, data->addtl->len);
1815 return drbg_generate_long(drbg, data->outbuf, data->outlen,
1816 &addtl);
1817 }
1818}
1819
1820/*
1821 * Reset the DRBG invoked by the kernel crypto API
1822 * The reset implies a full re-initialization of the DRBG. Similar to the
1823 * generate function of drbg_kcapi_random, this function extends the
1824 * kernel crypto API interface with struct drbg_gen
1825 */
1826static int drbg_kcapi_reset(struct crypto_rng *tfm, u8 *seed, unsigned int slen)
1827{
1828 struct drbg_state *drbg = crypto_rng_ctx(tfm);
1829 struct crypto_tfm *tfm_base = crypto_rng_tfm(tfm);
1830 bool pr = false;
1831 struct drbg_string seed_string;
1832 int coreref = 0;
1833
1834 drbg_uninstantiate(drbg);
1835 drbg_convert_tfm_core(crypto_tfm_alg_driver_name(tfm_base), &coreref,
1836 &pr);
1837 if (0 < slen) {
1838 drbg_string_fill(&seed_string, seed, slen);
1839 return drbg_instantiate(drbg, &seed_string, coreref, pr);
1840 } else {
1841 struct drbg_gen *data = (struct drbg_gen *)seed;
1842 /* allow invocation of API call with NULL, 0 */
1843 if (!data)
1844 return drbg_instantiate(drbg, NULL, coreref, pr);
1845 drbg_set_testdata(drbg, data->test_data);
1846 /* linked list variable is now local to allow modification */
1847 drbg_string_fill(&seed_string, data->addtl->buf,
1848 data->addtl->len);
1849 return drbg_instantiate(drbg, &seed_string, coreref, pr);
1850 }
1851}
1852
1853/***************************************************************
1854 * Kernel module: code to load the module
1855 ***************************************************************/
1856
1857/*
1858 * Tests as defined in 11.3.2 in addition to the cipher tests: testing
1859 * of the error handling.
1860 *
1861 * Note: testing of failing seed source as defined in 11.3.2 is not applicable
1862 * as seed source of get_random_bytes does not fail.
1863 *
1864 * Note 2: There is no sensible way of testing the reseed counter
1865 * enforcement, so skip it.
1866 */
1867static inline int __init drbg_healthcheck_sanity(void)
1868{
1869#ifdef CONFIG_CRYPTO_FIPS
1870 int len = 0;
1871#define OUTBUFLEN 16
1872 unsigned char buf[OUTBUFLEN];
1873 struct drbg_state *drbg = NULL;
1874 int ret = -EFAULT;
1875 int rc = -EFAULT;
1876 bool pr = false;
1877 int coreref = 0;
1878 struct drbg_string addtl;
1879 size_t max_addtllen, max_request_bytes;
1880
1881 /* only perform test in FIPS mode */
1882 if (!fips_enabled)
1883 return 0;
1884
1885#ifdef CONFIG_CRYPTO_DRBG_CTR
1886 drbg_convert_tfm_core("drbg_nopr_ctr_aes128", &coreref, &pr);
1887#elif defined CONFIG_CRYPTO_DRBG_HASH
1888 drbg_convert_tfm_core("drbg_nopr_sha256", &coreref, &pr);
1889#else
1890 drbg_convert_tfm_core("drbg_nopr_hmac_sha256", &coreref, &pr);
1891#endif
1892
1893 drbg = kzalloc(sizeof(struct drbg_state), GFP_KERNEL);
1894 if (!drbg)
1895 return -ENOMEM;
1896
1897 /*
1898 * if the following tests fail, it is likely that there is a buffer
1899 * overflow as buf is much smaller than the requested or provided
1900 * string lengths -- in case the error handling does not succeed
1901 * we may get an OOPS. And we want to get an OOPS as this is a
1902 * grave bug.
1903 */
1904
1905 /* get a valid instance of DRBG for following tests */
1906 ret = drbg_instantiate(drbg, NULL, coreref, pr);
1907 if (ret) {
1908 rc = ret;
1909 goto outbuf;
1910 }
1911 max_addtllen = drbg_max_addtl(drbg);
1912 max_request_bytes = drbg_max_request_bytes(drbg);
1913 drbg_string_fill(&addtl, buf, max_addtllen + 1);
1914 /* overflow addtllen with additonal info string */
1915 len = drbg_generate(drbg, buf, OUTBUFLEN, &addtl);
1916 BUG_ON(0 < len);
1917 /* overflow max_bits */
1918 len = drbg_generate(drbg, buf, (max_request_bytes + 1), NULL);
1919 BUG_ON(0 < len);
1920 drbg_uninstantiate(drbg);
1921
1922 /* overflow max addtllen with personalization string */
1923 ret = drbg_instantiate(drbg, &addtl, coreref, pr);
1924 BUG_ON(0 == ret);
1925 /* test uninstantated DRBG */
1926 len = drbg_generate(drbg, buf, (max_request_bytes + 1), NULL);
1927 BUG_ON(0 < len);
1928 /* all tests passed */
1929 rc = 0;
1930
1931 pr_devel("DRBG: Sanity tests for failure code paths successfully "
1932 "completed\n");
1933
1934 drbg_uninstantiate(drbg);
1935outbuf:
1936 kzfree(drbg);
1937 return rc;
1938#else /* CONFIG_CRYPTO_FIPS */
1939 return 0;
1940#endif /* CONFIG_CRYPTO_FIPS */
1941}
1942
1943static struct crypto_alg drbg_algs[22];
1944
1945/*
1946 * Fill the array drbg_algs used to register the different DRBGs
1947 * with the kernel crypto API. To fill the array, the information
1948 * from drbg_cores[] is used.
1949 */
1950static inline void __init drbg_fill_array(struct crypto_alg *alg,
1951 const struct drbg_core *core, int pr)
1952{
1953 int pos = 0;
1954 static int priority = 100;
1955
1956 memset(alg, 0, sizeof(struct crypto_alg));
1957 memcpy(alg->cra_name, "stdrng", 6);
1958 if (pr) {
1959 memcpy(alg->cra_driver_name, "drbg_pr_", 8);
1960 pos = 8;
1961 } else {
1962 memcpy(alg->cra_driver_name, "drbg_nopr_", 10);
1963 pos = 10;
1964 }
1965 memcpy(alg->cra_driver_name + pos, core->cra_name,
1966 strlen(core->cra_name));
1967
1968 alg->cra_priority = priority;
1969 priority++;
1970 /*
1971 * If FIPS mode enabled, the selected DRBG shall have the
1972 * highest cra_priority over other stdrng instances to ensure
1973 * it is selected.
1974 */
1975 if (fips_enabled)
1976 alg->cra_priority += 200;
1977
1978 alg->cra_flags = CRYPTO_ALG_TYPE_RNG;
1979 alg->cra_ctxsize = sizeof(struct drbg_state);
1980 alg->cra_type = &crypto_rng_type;
1981 alg->cra_module = THIS_MODULE;
1982 alg->cra_init = drbg_kcapi_init;
1983 alg->cra_exit = drbg_kcapi_cleanup;
1984 alg->cra_u.rng.rng_make_random = drbg_kcapi_random;
1985 alg->cra_u.rng.rng_reset = drbg_kcapi_reset;
1986 alg->cra_u.rng.seedsize = 0;
1987}
1988
1989static int __init drbg_init(void)
1990{
1991 unsigned int i = 0; /* pointer to drbg_algs */
1992 unsigned int j = 0; /* pointer to drbg_cores */
1993 int ret = -EFAULT;
1994
1995 ret = drbg_healthcheck_sanity();
1996 if (ret)
1997 return ret;
1998
1999 if (ARRAY_SIZE(drbg_cores) * 2 > ARRAY_SIZE(drbg_algs)) {
2000 pr_info("DRBG: Cannot register all DRBG types"
2001 "(slots needed: %zu, slots available: %zu)\n",
2002 ARRAY_SIZE(drbg_cores) * 2, ARRAY_SIZE(drbg_algs));
2003 return ret;
2004 }
2005
2006 /*
2007 * each DRBG definition can be used with PR and without PR, thus
2008 * we instantiate each DRBG in drbg_cores[] twice.
2009 *
2010 * As the order of placing them into the drbg_algs array matters
2011 * (the later DRBGs receive a higher cra_priority) we register the
2012 * prediction resistance DRBGs first as the should not be too
2013 * interesting.
2014 */
2015 for (j = 0; ARRAY_SIZE(drbg_cores) > j; j++, i++)
2016 drbg_fill_array(&drbg_algs[i], &drbg_cores[j], 1);
2017 for (j = 0; ARRAY_SIZE(drbg_cores) > j; j++, i++)
2018 drbg_fill_array(&drbg_algs[i], &drbg_cores[j], 0);
2019 return crypto_register_algs(drbg_algs, (ARRAY_SIZE(drbg_cores) * 2));
2020}
2021
2022static void __exit drbg_exit(void)
2023{
2024 crypto_unregister_algs(drbg_algs, (ARRAY_SIZE(drbg_cores) * 2));
2025}
2026
2027module_init(drbg_init);
2028module_exit(drbg_exit);
2029#ifndef CRYPTO_DRBG_HASH_STRING
2030#define CRYPTO_DRBG_HASH_STRING ""
2031#endif
2032#ifndef CRYPTO_DRBG_HMAC_STRING
2033#define CRYPTO_DRBG_HMAC_STRING ""
2034#endif
2035#ifndef CRYPTO_DRBG_CTR_STRING
2036#define CRYPTO_DRBG_CTR_STRING ""
2037#endif
2038MODULE_LICENSE("GPL");
2039MODULE_AUTHOR("Stephan Mueller <smueller@chronox.de>");
2040MODULE_DESCRIPTION("NIST SP800-90A Deterministic Random Bit Generator (DRBG) "
2041 "using following cores: "
2042 CRYPTO_DRBG_HASH_STRING
2043 CRYPTO_DRBG_HMAC_STRING
2044 CRYPTO_DRBG_CTR_STRING);
generated by cgit v1.2.2 (git 2.25.0) at 2024-12-03 10:18:47 -0500