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Stephan Mueller541af942014-05-31 15:44:17 +02001/*
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
Stephan Mueller541af942014-05-31 15:44:17 +0200102/***************************************************************
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 */
Stephan Mueller541af942014-05-31 15:44:17 +0200120 .blocklen_bytes = 16,
121 .cra_name = "ctr_aes128",
122 .backend_cra_name = "ecb(aes)",
123 }, {
124 .flags = DRBG_CTR | DRBG_STRENGTH192,
125 .statelen = 40, /* 320 bits as defined in 10.2.1 */
Stephan Mueller541af942014-05-31 15:44:17 +0200126 .blocklen_bytes = 16,
127 .cra_name = "ctr_aes192",
128 .backend_cra_name = "ecb(aes)",
129 }, {
130 .flags = DRBG_CTR | DRBG_STRENGTH256,
131 .statelen = 48, /* 384 bits as defined in 10.2.1 */
Stephan Mueller541af942014-05-31 15:44:17 +0200132 .blocklen_bytes = 16,
133 .cra_name = "ctr_aes256",
134 .backend_cra_name = "ecb(aes)",
135 },
136#endif /* CONFIG_CRYPTO_DRBG_CTR */
137#ifdef CONFIG_CRYPTO_DRBG_HASH
138 {
139 .flags = DRBG_HASH | DRBG_STRENGTH128,
140 .statelen = 55, /* 440 bits */
Stephan Mueller541af942014-05-31 15:44:17 +0200141 .blocklen_bytes = 20,
142 .cra_name = "sha1",
143 .backend_cra_name = "sha1",
144 }, {
145 .flags = DRBG_HASH | DRBG_STRENGTH256,
146 .statelen = 111, /* 888 bits */
Stephan Mueller541af942014-05-31 15:44:17 +0200147 .blocklen_bytes = 48,
148 .cra_name = "sha384",
149 .backend_cra_name = "sha384",
150 }, {
151 .flags = DRBG_HASH | DRBG_STRENGTH256,
152 .statelen = 111, /* 888 bits */
Stephan Mueller541af942014-05-31 15:44:17 +0200153 .blocklen_bytes = 64,
154 .cra_name = "sha512",
155 .backend_cra_name = "sha512",
156 }, {
157 .flags = DRBG_HASH | DRBG_STRENGTH256,
158 .statelen = 55, /* 440 bits */
Stephan Mueller541af942014-05-31 15:44:17 +0200159 .blocklen_bytes = 32,
160 .cra_name = "sha256",
161 .backend_cra_name = "sha256",
162 },
163#endif /* CONFIG_CRYPTO_DRBG_HASH */
164#ifdef CONFIG_CRYPTO_DRBG_HMAC
165 {
Stephan Mueller5b635e22014-07-06 02:26:37 +0200166 .flags = DRBG_HMAC | DRBG_STRENGTH128,
Stephan Mueller541af942014-05-31 15:44:17 +0200167 .statelen = 20, /* block length of cipher */
Stephan Mueller541af942014-05-31 15:44:17 +0200168 .blocklen_bytes = 20,
169 .cra_name = "hmac_sha1",
170 .backend_cra_name = "hmac(sha1)",
171 }, {
172 .flags = DRBG_HMAC | DRBG_STRENGTH256,
173 .statelen = 48, /* block length of cipher */
Stephan Mueller541af942014-05-31 15:44:17 +0200174 .blocklen_bytes = 48,
175 .cra_name = "hmac_sha384",
176 .backend_cra_name = "hmac(sha384)",
177 }, {
178 .flags = DRBG_HMAC | DRBG_STRENGTH256,
179 .statelen = 64, /* block length of cipher */
Stephan Mueller541af942014-05-31 15:44:17 +0200180 .blocklen_bytes = 64,
181 .cra_name = "hmac_sha512",
182 .backend_cra_name = "hmac(sha512)",
183 }, {
184 .flags = DRBG_HMAC | DRBG_STRENGTH256,
185 .statelen = 32, /* block length of cipher */
Stephan Mueller541af942014-05-31 15:44:17 +0200186 .blocklen_bytes = 32,
187 .cra_name = "hmac_sha256",
188 .backend_cra_name = "hmac(sha256)",
189 },
190#endif /* CONFIG_CRYPTO_DRBG_HMAC */
191};
192
193/******************************************************************
194 * Generic helper functions
195 ******************************************************************/
196
197/*
198 * Return strength of DRBG according to SP800-90A section 8.4
199 *
200 * @flags DRBG flags reference
201 *
202 * Return: normalized strength in *bytes* value or 32 as default
203 * to counter programming errors
204 */
205static inline unsigned short drbg_sec_strength(drbg_flag_t flags)
206{
207 switch (flags & DRBG_STRENGTH_MASK) {
208 case DRBG_STRENGTH128:
209 return 16;
210 case DRBG_STRENGTH192:
211 return 24;
212 case DRBG_STRENGTH256:
213 return 32;
214 default:
215 return 32;
216 }
217}
218
219/*
220 * FIPS 140-2 continuous self test
221 * The test is performed on the result of one round of the output
222 * function. Thus, the function implicitly knows the size of the
223 * buffer.
224 *
225 * The FIPS test can be called in an endless loop until it returns
226 * true. Although the code looks like a potential for a deadlock, it
227 * is not the case, because returning a false cannot mathematically
228 * occur (except once when a reseed took place and the updated state
229 * would is now set up such that the generation of new value returns
230 * an identical one -- this is most unlikely and would happen only once).
231 * Thus, if this function repeatedly returns false and thus would cause
232 * a deadlock, the integrity of the entire kernel is lost.
233 *
234 * @drbg DRBG handle
235 * @buf output buffer of random data to be checked
236 *
237 * return:
238 * true on success
239 * false on error
240 */
241static bool drbg_fips_continuous_test(struct drbg_state *drbg,
242 const unsigned char *buf)
243{
244#ifdef CONFIG_CRYPTO_FIPS
245 int ret = 0;
246 /* skip test if we test the overall system */
247 if (drbg->test_data)
248 return true;
249 /* only perform test in FIPS mode */
250 if (0 == fips_enabled)
251 return true;
252 if (!drbg->fips_primed) {
253 /* Priming of FIPS test */
254 memcpy(drbg->prev, buf, drbg_blocklen(drbg));
255 drbg->fips_primed = true;
256 /* return false due to priming, i.e. another round is needed */
257 return false;
258 }
259 ret = memcmp(drbg->prev, buf, drbg_blocklen(drbg));
260 memcpy(drbg->prev, buf, drbg_blocklen(drbg));
261 /* the test shall pass when the two compared values are not equal */
262 return ret != 0;
263#else
264 return true;
265#endif /* CONFIG_CRYPTO_FIPS */
266}
267
268/*
269 * Convert an integer into a byte representation of this integer.
270 * The byte representation is big-endian
271 *
Stephan Mueller541af942014-05-31 15:44:17 +0200272 * @val value to be converted
Stephan Mueller72f3e002014-08-17 17:37:34 +0200273 * @buf buffer holding the converted integer -- caller must ensure that
274 * buffer size is at least 32 bit
Stephan Mueller541af942014-05-31 15:44:17 +0200275 */
276#if (defined(CONFIG_CRYPTO_DRBG_HASH) || defined(CONFIG_CRYPTO_DRBG_CTR))
Stephan Mueller72f3e002014-08-17 17:37:34 +0200277static inline void drbg_cpu_to_be32(__u32 val, unsigned char *buf)
Stephan Mueller541af942014-05-31 15:44:17 +0200278{
Stephan Mueller72f3e002014-08-17 17:37:34 +0200279 struct s {
Stephan Mueller7c8ae032014-08-26 09:32:24 +0200280 __be32 conv;
Stephan Mueller72f3e002014-08-17 17:37:34 +0200281 };
282 struct s *conversion = (struct s *) buf;
Stephan Mueller541af942014-05-31 15:44:17 +0200283
Stephan Mueller72f3e002014-08-17 17:37:34 +0200284 conversion->conv = cpu_to_be32(val);
Stephan Mueller541af942014-05-31 15:44:17 +0200285}
286
287/*
288 * Increment buffer
289 *
290 * @dst buffer to increment
291 * @add value to add
292 */
293static inline void drbg_add_buf(unsigned char *dst, size_t dstlen,
294 const unsigned char *add, size_t addlen)
295{
296 /* implied: dstlen > addlen */
297 unsigned char *dstptr;
298 const unsigned char *addptr;
299 unsigned int remainder = 0;
300 size_t len = addlen;
301
302 dstptr = dst + (dstlen-1);
303 addptr = add + (addlen-1);
304 while (len) {
305 remainder += *dstptr + *addptr;
306 *dstptr = remainder & 0xff;
307 remainder >>= 8;
308 len--; dstptr--; addptr--;
309 }
310 len = dstlen - addlen;
311 while (len && remainder > 0) {
312 remainder = *dstptr + 1;
313 *dstptr = remainder & 0xff;
314 remainder >>= 8;
315 len--; dstptr--;
316 }
317}
318#endif /* defined(CONFIG_CRYPTO_DRBG_HASH) || defined(CONFIG_CRYPTO_DRBG_CTR) */
319
320/******************************************************************
321 * CTR DRBG callback functions
322 ******************************************************************/
323
324#ifdef CONFIG_CRYPTO_DRBG_CTR
Stephan Muellere25e47e2014-07-06 02:23:03 +0200325#define CRYPTO_DRBG_CTR_STRING "CTR "
Stephan Mueller541af942014-05-31 15:44:17 +0200326static int drbg_kcapi_sym(struct drbg_state *drbg, const unsigned char *key,
327 unsigned char *outval, const struct drbg_string *in);
328static int drbg_init_sym_kernel(struct drbg_state *drbg);
329static int drbg_fini_sym_kernel(struct drbg_state *drbg);
330
331/* BCC function for CTR DRBG as defined in 10.4.3 */
332static int drbg_ctr_bcc(struct drbg_state *drbg,
333 unsigned char *out, const unsigned char *key,
Stephan Mueller8c987162014-06-28 21:58:24 +0200334 struct list_head *in)
Stephan Mueller541af942014-05-31 15:44:17 +0200335{
Stephan Mueller8c987162014-06-28 21:58:24 +0200336 int ret = 0;
337 struct drbg_string *curr = NULL;
Stephan Mueller541af942014-05-31 15:44:17 +0200338 struct drbg_string data;
Stephan Mueller8c987162014-06-28 21:58:24 +0200339 short cnt = 0;
Stephan Mueller541af942014-05-31 15:44:17 +0200340
341 drbg_string_fill(&data, out, drbg_blocklen(drbg));
342
343 /* 10.4.3 step 1 */
344 memset(out, 0, drbg_blocklen(drbg));
345
346 /* 10.4.3 step 2 / 4 */
Stephan Mueller8c987162014-06-28 21:58:24 +0200347 list_for_each_entry(curr, in, list) {
348 const unsigned char *pos = curr->buf;
349 size_t len = curr->len;
Stephan Mueller541af942014-05-31 15:44:17 +0200350 /* 10.4.3 step 4.1 */
Stephan Mueller8c987162014-06-28 21:58:24 +0200351 while (len) {
352 /* 10.4.3 step 4.2 */
353 if (drbg_blocklen(drbg) == cnt) {
354 cnt = 0;
355 ret = drbg_kcapi_sym(drbg, key, out, &data);
356 if (ret)
357 return ret;
Stephan Mueller541af942014-05-31 15:44:17 +0200358 }
Stephan Mueller8c987162014-06-28 21:58:24 +0200359 out[cnt] ^= *pos;
360 pos++;
361 cnt++;
362 len--;
Stephan Mueller541af942014-05-31 15:44:17 +0200363 }
Stephan Mueller541af942014-05-31 15:44:17 +0200364 }
Stephan Mueller8c987162014-06-28 21:58:24 +0200365 /* 10.4.3 step 4.2 for last block */
366 if (cnt)
367 ret = drbg_kcapi_sym(drbg, key, out, &data);
368
369 return ret;
Stephan Mueller541af942014-05-31 15:44:17 +0200370}
371
372/*
373 * scratchpad usage: drbg_ctr_update is interlinked with drbg_ctr_df
374 * (and drbg_ctr_bcc, but this function does not need any temporary buffers),
375 * the scratchpad is used as follows:
376 * drbg_ctr_update:
377 * temp
378 * start: drbg->scratchpad
379 * length: drbg_statelen(drbg) + drbg_blocklen(drbg)
380 * note: the cipher writing into this variable works
381 * blocklen-wise. Now, when the statelen is not a multiple
382 * of blocklen, the generateion loop below "spills over"
383 * by at most blocklen. Thus, we need to give sufficient
384 * memory.
385 * df_data
386 * start: drbg->scratchpad +
387 * drbg_statelen(drbg) + drbg_blocklen(drbg)
388 * length: drbg_statelen(drbg)
389 *
390 * drbg_ctr_df:
391 * pad
392 * start: df_data + drbg_statelen(drbg)
393 * length: drbg_blocklen(drbg)
394 * iv
395 * start: pad + drbg_blocklen(drbg)
396 * length: drbg_blocklen(drbg)
397 * temp
398 * start: iv + drbg_blocklen(drbg)
Stephan Mueller8fecaad2014-07-01 17:08:48 +0200399 * length: drbg_satelen(drbg) + drbg_blocklen(drbg)
400 * note: temp is the buffer that the BCC function operates
401 * on. BCC operates blockwise. drbg_statelen(drbg)
402 * is sufficient when the DRBG state length is a multiple
403 * of the block size. For AES192 (and maybe other ciphers)
404 * this is not correct and the length for temp is
405 * insufficient (yes, that also means for such ciphers,
406 * the final output of all BCC rounds are truncated).
407 * Therefore, add drbg_blocklen(drbg) to cover all
408 * possibilities.
Stephan Mueller541af942014-05-31 15:44:17 +0200409 */
410
411/* Derivation Function for CTR DRBG as defined in 10.4.2 */
412static int drbg_ctr_df(struct drbg_state *drbg,
413 unsigned char *df_data, size_t bytes_to_return,
Stephan Mueller8c987162014-06-28 21:58:24 +0200414 struct list_head *seedlist)
Stephan Mueller541af942014-05-31 15:44:17 +0200415{
416 int ret = -EFAULT;
417 unsigned char L_N[8];
418 /* S3 is input */
419 struct drbg_string S1, S2, S4, cipherin;
Stephan Mueller8c987162014-06-28 21:58:24 +0200420 LIST_HEAD(bcc_list);
Stephan Mueller541af942014-05-31 15:44:17 +0200421 unsigned char *pad = df_data + drbg_statelen(drbg);
422 unsigned char *iv = pad + drbg_blocklen(drbg);
423 unsigned char *temp = iv + drbg_blocklen(drbg);
424 size_t padlen = 0;
425 unsigned int templen = 0;
426 /* 10.4.2 step 7 */
427 unsigned int i = 0;
428 /* 10.4.2 step 8 */
429 const unsigned char *K = (unsigned char *)
430 "\x00\x01\x02\x03\x04\x05\x06\x07"
431 "\x08\x09\x0a\x0b\x0c\x0d\x0e\x0f"
432 "\x10\x11\x12\x13\x14\x15\x16\x17"
433 "\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f";
434 unsigned char *X;
435 size_t generated_len = 0;
436 size_t inputlen = 0;
Stephan Mueller8c987162014-06-28 21:58:24 +0200437 struct drbg_string *seed = NULL;
Stephan Mueller541af942014-05-31 15:44:17 +0200438
439 memset(pad, 0, drbg_blocklen(drbg));
440 memset(iv, 0, drbg_blocklen(drbg));
441 memset(temp, 0, drbg_statelen(drbg));
442
443 /* 10.4.2 step 1 is implicit as we work byte-wise */
444
445 /* 10.4.2 step 2 */
446 if ((512/8) < bytes_to_return)
447 return -EINVAL;
448
449 /* 10.4.2 step 2 -- calculate the entire length of all input data */
Stephan Mueller8c987162014-06-28 21:58:24 +0200450 list_for_each_entry(seed, seedlist, list)
451 inputlen += seed->len;
Stephan Mueller72f3e002014-08-17 17:37:34 +0200452 drbg_cpu_to_be32(inputlen, &L_N[0]);
Stephan Mueller541af942014-05-31 15:44:17 +0200453
454 /* 10.4.2 step 3 */
Stephan Mueller72f3e002014-08-17 17:37:34 +0200455 drbg_cpu_to_be32(bytes_to_return, &L_N[4]);
Stephan Mueller541af942014-05-31 15:44:17 +0200456
457 /* 10.4.2 step 5: length is L_N, input_string, one byte, padding */
458 padlen = (inputlen + sizeof(L_N) + 1) % (drbg_blocklen(drbg));
459 /* wrap the padlen appropriately */
460 if (padlen)
461 padlen = drbg_blocklen(drbg) - padlen;
462 /*
463 * pad / padlen contains the 0x80 byte and the following zero bytes.
464 * As the calculated padlen value only covers the number of zero
465 * bytes, this value has to be incremented by one for the 0x80 byte.
466 */
467 padlen++;
468 pad[0] = 0x80;
469
470 /* 10.4.2 step 4 -- first fill the linked list and then order it */
471 drbg_string_fill(&S1, iv, drbg_blocklen(drbg));
Stephan Mueller8c987162014-06-28 21:58:24 +0200472 list_add_tail(&S1.list, &bcc_list);
Stephan Mueller541af942014-05-31 15:44:17 +0200473 drbg_string_fill(&S2, L_N, sizeof(L_N));
Stephan Mueller8c987162014-06-28 21:58:24 +0200474 list_add_tail(&S2.list, &bcc_list);
475 list_splice_tail(seedlist, &bcc_list);
Stephan Mueller541af942014-05-31 15:44:17 +0200476 drbg_string_fill(&S4, pad, padlen);
Stephan Mueller8c987162014-06-28 21:58:24 +0200477 list_add_tail(&S4.list, &bcc_list);
Stephan Mueller541af942014-05-31 15:44:17 +0200478
479 /* 10.4.2 step 9 */
480 while (templen < (drbg_keylen(drbg) + (drbg_blocklen(drbg)))) {
481 /*
482 * 10.4.2 step 9.1 - the padding is implicit as the buffer
483 * holds zeros after allocation -- even the increment of i
484 * is irrelevant as the increment remains within length of i
485 */
Stephan Mueller72f3e002014-08-17 17:37:34 +0200486 drbg_cpu_to_be32(i, iv);
Stephan Mueller541af942014-05-31 15:44:17 +0200487 /* 10.4.2 step 9.2 -- BCC and concatenation with temp */
Stephan Mueller8c987162014-06-28 21:58:24 +0200488 ret = drbg_ctr_bcc(drbg, temp + templen, K, &bcc_list);
Stephan Mueller541af942014-05-31 15:44:17 +0200489 if (ret)
490 goto out;
491 /* 10.4.2 step 9.3 */
492 i++;
493 templen += drbg_blocklen(drbg);
494 }
495
496 /* 10.4.2 step 11 */
497 X = temp + (drbg_keylen(drbg));
498 drbg_string_fill(&cipherin, X, drbg_blocklen(drbg));
499
500 /* 10.4.2 step 12: overwriting of outval is implemented in next step */
501
502 /* 10.4.2 step 13 */
503 while (generated_len < bytes_to_return) {
504 short blocklen = 0;
505 /*
506 * 10.4.2 step 13.1: the truncation of the key length is
507 * implicit as the key is only drbg_blocklen in size based on
508 * the implementation of the cipher function callback
509 */
510 ret = drbg_kcapi_sym(drbg, temp, X, &cipherin);
511 if (ret)
512 goto out;
513 blocklen = (drbg_blocklen(drbg) <
514 (bytes_to_return - generated_len)) ?
515 drbg_blocklen(drbg) :
516 (bytes_to_return - generated_len);
517 /* 10.4.2 step 13.2 and 14 */
518 memcpy(df_data + generated_len, X, blocklen);
519 generated_len += blocklen;
520 }
521
522 ret = 0;
523
524out:
525 memset(iv, 0, drbg_blocklen(drbg));
526 memset(temp, 0, drbg_statelen(drbg));
527 memset(pad, 0, drbg_blocklen(drbg));
528 return ret;
529}
530
Stephan Mueller72e7c252014-07-06 02:24:35 +0200531/*
532 * update function of CTR DRBG as defined in 10.2.1.2
533 *
534 * The reseed variable has an enhanced meaning compared to the update
535 * functions of the other DRBGs as follows:
536 * 0 => initial seed from initialization
537 * 1 => reseed via drbg_seed
538 * 2 => first invocation from drbg_ctr_update when addtl is present. In
539 * this case, the df_data scratchpad is not deleted so that it is
540 * available for another calls to prevent calling the DF function
541 * again.
542 * 3 => second invocation from drbg_ctr_update. When the update function
543 * was called with addtl, the df_data memory already contains the
544 * DFed addtl information and we do not need to call DF again.
545 */
Stephan Mueller8c987162014-06-28 21:58:24 +0200546static int drbg_ctr_update(struct drbg_state *drbg, struct list_head *seed,
547 int reseed)
Stephan Mueller541af942014-05-31 15:44:17 +0200548{
549 int ret = -EFAULT;
550 /* 10.2.1.2 step 1 */
551 unsigned char *temp = drbg->scratchpad;
552 unsigned char *df_data = drbg->scratchpad + drbg_statelen(drbg) +
553 drbg_blocklen(drbg);
554 unsigned char *temp_p, *df_data_p; /* pointer to iterate over buffers */
555 unsigned int len = 0;
556 struct drbg_string cipherin;
557 unsigned char prefix = DRBG_PREFIX1;
558
559 memset(temp, 0, drbg_statelen(drbg) + drbg_blocklen(drbg));
Stephan Mueller72e7c252014-07-06 02:24:35 +0200560 if (3 > reseed)
561 memset(df_data, 0, drbg_statelen(drbg));
Stephan Mueller541af942014-05-31 15:44:17 +0200562
563 /* 10.2.1.3.2 step 2 and 10.2.1.4.2 step 2 */
Stephan Mueller8c987162014-06-28 21:58:24 +0200564 if (seed) {
565 ret = drbg_ctr_df(drbg, df_data, drbg_statelen(drbg), seed);
Stephan Mueller541af942014-05-31 15:44:17 +0200566 if (ret)
567 goto out;
568 }
569
570 drbg_string_fill(&cipherin, drbg->V, drbg_blocklen(drbg));
571 /*
572 * 10.2.1.3.2 steps 2 and 3 are already covered as the allocation
573 * zeroizes all memory during initialization
574 */
575 while (len < (drbg_statelen(drbg))) {
576 /* 10.2.1.2 step 2.1 */
577 drbg_add_buf(drbg->V, drbg_blocklen(drbg), &prefix, 1);
578 /*
579 * 10.2.1.2 step 2.2 */
580 ret = drbg_kcapi_sym(drbg, drbg->C, temp + len, &cipherin);
581 if (ret)
582 goto out;
583 /* 10.2.1.2 step 2.3 and 3 */
584 len += drbg_blocklen(drbg);
585 }
586
587 /* 10.2.1.2 step 4 */
588 temp_p = temp;
589 df_data_p = df_data;
590 for (len = 0; len < drbg_statelen(drbg); len++) {
591 *temp_p ^= *df_data_p;
592 df_data_p++; temp_p++;
593 }
594
595 /* 10.2.1.2 step 5 */
596 memcpy(drbg->C, temp, drbg_keylen(drbg));
597 /* 10.2.1.2 step 6 */
598 memcpy(drbg->V, temp + drbg_keylen(drbg), drbg_blocklen(drbg));
599 ret = 0;
600
601out:
602 memset(temp, 0, drbg_statelen(drbg) + drbg_blocklen(drbg));
Stephan Mueller72e7c252014-07-06 02:24:35 +0200603 if (2 != reseed)
604 memset(df_data, 0, drbg_statelen(drbg));
Stephan Mueller541af942014-05-31 15:44:17 +0200605 return ret;
606}
607
608/*
609 * scratchpad use: drbg_ctr_update is called independently from
610 * drbg_ctr_extract_bytes. Therefore, the scratchpad is reused
611 */
612/* Generate function of CTR DRBG as defined in 10.2.1.5.2 */
613static int drbg_ctr_generate(struct drbg_state *drbg,
614 unsigned char *buf, unsigned int buflen,
Stephan Mueller27e4de22014-07-06 02:25:36 +0200615 struct list_head *addtl)
Stephan Mueller541af942014-05-31 15:44:17 +0200616{
617 int len = 0;
618 int ret = 0;
619 struct drbg_string data;
620 unsigned char prefix = DRBG_PREFIX1;
621
622 memset(drbg->scratchpad, 0, drbg_blocklen(drbg));
623
624 /* 10.2.1.5.2 step 2 */
Stephan Mueller27e4de22014-07-06 02:25:36 +0200625 if (addtl && !list_empty(addtl)) {
626 ret = drbg_ctr_update(drbg, addtl, 2);
Stephan Mueller541af942014-05-31 15:44:17 +0200627 if (ret)
628 return 0;
629 }
630
631 /* 10.2.1.5.2 step 4.1 */
632 drbg_add_buf(drbg->V, drbg_blocklen(drbg), &prefix, 1);
633 drbg_string_fill(&data, drbg->V, drbg_blocklen(drbg));
634 while (len < buflen) {
635 int outlen = 0;
636 /* 10.2.1.5.2 step 4.2 */
637 ret = drbg_kcapi_sym(drbg, drbg->C, drbg->scratchpad, &data);
638 if (ret) {
639 len = ret;
640 goto out;
641 }
642 outlen = (drbg_blocklen(drbg) < (buflen - len)) ?
643 drbg_blocklen(drbg) : (buflen - len);
644 if (!drbg_fips_continuous_test(drbg, drbg->scratchpad)) {
645 /* 10.2.1.5.2 step 6 */
646 drbg_add_buf(drbg->V, drbg_blocklen(drbg), &prefix, 1);
647 continue;
648 }
649 /* 10.2.1.5.2 step 4.3 */
650 memcpy(buf + len, drbg->scratchpad, outlen);
651 len += outlen;
652 /* 10.2.1.5.2 step 6 */
653 if (len < buflen)
654 drbg_add_buf(drbg->V, drbg_blocklen(drbg), &prefix, 1);
655 }
656
Stephan Mueller72e7c252014-07-06 02:24:35 +0200657 /* 10.2.1.5.2 step 6 */
658 ret = drbg_ctr_update(drbg, NULL, 3);
Stephan Mueller541af942014-05-31 15:44:17 +0200659 if (ret)
660 len = ret;
661
662out:
663 memset(drbg->scratchpad, 0, drbg_blocklen(drbg));
664 return len;
665}
666
667static struct drbg_state_ops drbg_ctr_ops = {
668 .update = drbg_ctr_update,
669 .generate = drbg_ctr_generate,
670 .crypto_init = drbg_init_sym_kernel,
671 .crypto_fini = drbg_fini_sym_kernel,
672};
673#endif /* CONFIG_CRYPTO_DRBG_CTR */
674
675/******************************************************************
676 * HMAC DRBG callback functions
677 ******************************************************************/
678
679#if defined(CONFIG_CRYPTO_DRBG_HASH) || defined(CONFIG_CRYPTO_DRBG_HMAC)
680static int drbg_kcapi_hash(struct drbg_state *drbg, const unsigned char *key,
Stephan Mueller8c987162014-06-28 21:58:24 +0200681 unsigned char *outval, const struct list_head *in);
Stephan Mueller541af942014-05-31 15:44:17 +0200682static int drbg_init_hash_kernel(struct drbg_state *drbg);
683static int drbg_fini_hash_kernel(struct drbg_state *drbg);
684#endif /* (CONFIG_CRYPTO_DRBG_HASH || CONFIG_CRYPTO_DRBG_HMAC) */
685
686#ifdef CONFIG_CRYPTO_DRBG_HMAC
Stephan Muellere25e47e2014-07-06 02:23:03 +0200687#define CRYPTO_DRBG_HMAC_STRING "HMAC "
Stephan Mueller541af942014-05-31 15:44:17 +0200688/* update function of HMAC DRBG as defined in 10.1.2.2 */
Stephan Mueller8c987162014-06-28 21:58:24 +0200689static int drbg_hmac_update(struct drbg_state *drbg, struct list_head *seed,
690 int reseed)
Stephan Mueller541af942014-05-31 15:44:17 +0200691{
692 int ret = -EFAULT;
693 int i = 0;
Stephan Mueller8c987162014-06-28 21:58:24 +0200694 struct drbg_string seed1, seed2, vdata;
695 LIST_HEAD(seedlist);
696 LIST_HEAD(vdatalist);
Stephan Mueller541af942014-05-31 15:44:17 +0200697
Stephan Muellerf072f0e2014-08-17 17:38:58 +0200698 if (!reseed)
699 /* 10.1.2.3 step 2 -- memset(0) of C is implicit with kzalloc */
Stephan Mueller541af942014-05-31 15:44:17 +0200700 memset(drbg->V, 1, drbg_statelen(drbg));
Stephan Mueller541af942014-05-31 15:44:17 +0200701
702 drbg_string_fill(&seed1, drbg->V, drbg_statelen(drbg));
Stephan Mueller8c987162014-06-28 21:58:24 +0200703 list_add_tail(&seed1.list, &seedlist);
Stephan Mueller541af942014-05-31 15:44:17 +0200704 /* buffer of seed2 will be filled in for loop below with one byte */
705 drbg_string_fill(&seed2, NULL, 1);
Stephan Mueller8c987162014-06-28 21:58:24 +0200706 list_add_tail(&seed2.list, &seedlist);
Stephan Mueller541af942014-05-31 15:44:17 +0200707 /* input data of seed is allowed to be NULL at this point */
Stephan Mueller8c987162014-06-28 21:58:24 +0200708 if (seed)
709 list_splice_tail(seed, &seedlist);
Stephan Mueller541af942014-05-31 15:44:17 +0200710
Stephan Mueller8c987162014-06-28 21:58:24 +0200711 drbg_string_fill(&vdata, drbg->V, drbg_statelen(drbg));
712 list_add_tail(&vdata.list, &vdatalist);
Stephan Mueller541af942014-05-31 15:44:17 +0200713 for (i = 2; 0 < i; i--) {
714 /* first round uses 0x0, second 0x1 */
715 unsigned char prefix = DRBG_PREFIX0;
716 if (1 == i)
717 prefix = DRBG_PREFIX1;
718 /* 10.1.2.2 step 1 and 4 -- concatenation and HMAC for key */
719 seed2.buf = &prefix;
Stephan Mueller8c987162014-06-28 21:58:24 +0200720 ret = drbg_kcapi_hash(drbg, drbg->C, drbg->C, &seedlist);
Stephan Mueller541af942014-05-31 15:44:17 +0200721 if (ret)
722 return ret;
723
724 /* 10.1.2.2 step 2 and 5 -- HMAC for V */
Stephan Mueller8c987162014-06-28 21:58:24 +0200725 ret = drbg_kcapi_hash(drbg, drbg->C, drbg->V, &vdatalist);
Stephan Mueller541af942014-05-31 15:44:17 +0200726 if (ret)
727 return ret;
728
729 /* 10.1.2.2 step 3 */
Stephan Mueller8c987162014-06-28 21:58:24 +0200730 if (!seed)
Stephan Mueller541af942014-05-31 15:44:17 +0200731 return ret;
732 }
733
734 return 0;
735}
736
737/* generate function of HMAC DRBG as defined in 10.1.2.5 */
738static int drbg_hmac_generate(struct drbg_state *drbg,
739 unsigned char *buf,
740 unsigned int buflen,
Stephan Mueller27e4de22014-07-06 02:25:36 +0200741 struct list_head *addtl)
Stephan Mueller541af942014-05-31 15:44:17 +0200742{
743 int len = 0;
744 int ret = 0;
745 struct drbg_string data;
Stephan Mueller8c987162014-06-28 21:58:24 +0200746 LIST_HEAD(datalist);
Stephan Mueller541af942014-05-31 15:44:17 +0200747
748 /* 10.1.2.5 step 2 */
Stephan Mueller27e4de22014-07-06 02:25:36 +0200749 if (addtl && !list_empty(addtl)) {
750 ret = drbg_hmac_update(drbg, addtl, 1);
Stephan Mueller541af942014-05-31 15:44:17 +0200751 if (ret)
752 return ret;
753 }
754
755 drbg_string_fill(&data, drbg->V, drbg_statelen(drbg));
Stephan Mueller8c987162014-06-28 21:58:24 +0200756 list_add_tail(&data.list, &datalist);
Stephan Mueller541af942014-05-31 15:44:17 +0200757 while (len < buflen) {
758 unsigned int outlen = 0;
759 /* 10.1.2.5 step 4.1 */
Stephan Mueller8c987162014-06-28 21:58:24 +0200760 ret = drbg_kcapi_hash(drbg, drbg->C, drbg->V, &datalist);
Stephan Mueller541af942014-05-31 15:44:17 +0200761 if (ret)
762 return ret;
763 outlen = (drbg_blocklen(drbg) < (buflen - len)) ?
764 drbg_blocklen(drbg) : (buflen - len);
765 if (!drbg_fips_continuous_test(drbg, drbg->V))
766 continue;
767
768 /* 10.1.2.5 step 4.2 */
769 memcpy(buf + len, drbg->V, outlen);
770 len += outlen;
771 }
772
773 /* 10.1.2.5 step 6 */
Stephan Mueller27e4de22014-07-06 02:25:36 +0200774 if (addtl && !list_empty(addtl))
775 ret = drbg_hmac_update(drbg, addtl, 1);
776 else
Stephan Mueller8c987162014-06-28 21:58:24 +0200777 ret = drbg_hmac_update(drbg, NULL, 1);
Stephan Mueller541af942014-05-31 15:44:17 +0200778 if (ret)
779 return ret;
780
781 return len;
782}
783
784static struct drbg_state_ops drbg_hmac_ops = {
785 .update = drbg_hmac_update,
786 .generate = drbg_hmac_generate,
787 .crypto_init = drbg_init_hash_kernel,
788 .crypto_fini = drbg_fini_hash_kernel,
789
790};
791#endif /* CONFIG_CRYPTO_DRBG_HMAC */
792
793/******************************************************************
794 * Hash DRBG callback functions
795 ******************************************************************/
796
797#ifdef CONFIG_CRYPTO_DRBG_HASH
Stephan Muellere25e47e2014-07-06 02:23:03 +0200798#define CRYPTO_DRBG_HASH_STRING "HASH "
Stephan Mueller541af942014-05-31 15:44:17 +0200799/*
800 * scratchpad usage: as drbg_hash_update and drbg_hash_df are used
801 * interlinked, the scratchpad is used as follows:
802 * drbg_hash_update
803 * start: drbg->scratchpad
804 * length: drbg_statelen(drbg)
805 * drbg_hash_df:
806 * start: drbg->scratchpad + drbg_statelen(drbg)
807 * length: drbg_blocklen(drbg)
808 *
809 * drbg_hash_process_addtl uses the scratchpad, but fully completes
810 * before either of the functions mentioned before are invoked. Therefore,
811 * drbg_hash_process_addtl does not need to be specifically considered.
812 */
813
814/* Derivation Function for Hash DRBG as defined in 10.4.1 */
815static int drbg_hash_df(struct drbg_state *drbg,
816 unsigned char *outval, size_t outlen,
Stephan Mueller8c987162014-06-28 21:58:24 +0200817 struct list_head *entropylist)
Stephan Mueller541af942014-05-31 15:44:17 +0200818{
819 int ret = 0;
820 size_t len = 0;
821 unsigned char input[5];
822 unsigned char *tmp = drbg->scratchpad + drbg_statelen(drbg);
Stephan Mueller8c987162014-06-28 21:58:24 +0200823 struct drbg_string data;
Stephan Mueller541af942014-05-31 15:44:17 +0200824
825 memset(tmp, 0, drbg_blocklen(drbg));
826
827 /* 10.4.1 step 3 */
828 input[0] = 1;
Stephan Mueller72f3e002014-08-17 17:37:34 +0200829 drbg_cpu_to_be32((outlen * 8), &input[1]);
Stephan Mueller541af942014-05-31 15:44:17 +0200830
831 /* 10.4.1 step 4.1 -- concatenation of data for input into hash */
Stephan Mueller8c987162014-06-28 21:58:24 +0200832 drbg_string_fill(&data, input, 5);
833 list_add(&data.list, entropylist);
Stephan Mueller541af942014-05-31 15:44:17 +0200834
835 /* 10.4.1 step 4 */
836 while (len < outlen) {
837 short blocklen = 0;
838 /* 10.4.1 step 4.1 */
Stephan Mueller8c987162014-06-28 21:58:24 +0200839 ret = drbg_kcapi_hash(drbg, NULL, tmp, entropylist);
Stephan Mueller541af942014-05-31 15:44:17 +0200840 if (ret)
841 goto out;
842 /* 10.4.1 step 4.2 */
843 input[0]++;
844 blocklen = (drbg_blocklen(drbg) < (outlen - len)) ?
845 drbg_blocklen(drbg) : (outlen - len);
846 memcpy(outval + len, tmp, blocklen);
847 len += blocklen;
848 }
849
850out:
851 memset(tmp, 0, drbg_blocklen(drbg));
852 return ret;
853}
854
855/* update function for Hash DRBG as defined in 10.1.1.2 / 10.1.1.3 */
Stephan Mueller8c987162014-06-28 21:58:24 +0200856static int drbg_hash_update(struct drbg_state *drbg, struct list_head *seed,
Stephan Mueller541af942014-05-31 15:44:17 +0200857 int reseed)
858{
859 int ret = 0;
860 struct drbg_string data1, data2;
Stephan Mueller8c987162014-06-28 21:58:24 +0200861 LIST_HEAD(datalist);
862 LIST_HEAD(datalist2);
Stephan Mueller541af942014-05-31 15:44:17 +0200863 unsigned char *V = drbg->scratchpad;
864 unsigned char prefix = DRBG_PREFIX1;
865
866 memset(drbg->scratchpad, 0, drbg_statelen(drbg));
867 if (!seed)
868 return -EINVAL;
869
870 if (reseed) {
871 /* 10.1.1.3 step 1 */
872 memcpy(V, drbg->V, drbg_statelen(drbg));
873 drbg_string_fill(&data1, &prefix, 1);
Stephan Mueller8c987162014-06-28 21:58:24 +0200874 list_add_tail(&data1.list, &datalist);
Stephan Mueller541af942014-05-31 15:44:17 +0200875 drbg_string_fill(&data2, V, drbg_statelen(drbg));
Stephan Mueller8c987162014-06-28 21:58:24 +0200876 list_add_tail(&data2.list, &datalist);
Stephan Mueller541af942014-05-31 15:44:17 +0200877 }
Stephan Mueller8c987162014-06-28 21:58:24 +0200878 list_splice_tail(seed, &datalist);
Stephan Mueller541af942014-05-31 15:44:17 +0200879
880 /* 10.1.1.2 / 10.1.1.3 step 2 and 3 */
Stephan Mueller8c987162014-06-28 21:58:24 +0200881 ret = drbg_hash_df(drbg, drbg->V, drbg_statelen(drbg), &datalist);
Stephan Mueller541af942014-05-31 15:44:17 +0200882 if (ret)
883 goto out;
884
885 /* 10.1.1.2 / 10.1.1.3 step 4 */
886 prefix = DRBG_PREFIX0;
887 drbg_string_fill(&data1, &prefix, 1);
Stephan Mueller8c987162014-06-28 21:58:24 +0200888 list_add_tail(&data1.list, &datalist2);
Stephan Mueller541af942014-05-31 15:44:17 +0200889 drbg_string_fill(&data2, drbg->V, drbg_statelen(drbg));
Stephan Mueller8c987162014-06-28 21:58:24 +0200890 list_add_tail(&data2.list, &datalist2);
Stephan Mueller541af942014-05-31 15:44:17 +0200891 /* 10.1.1.2 / 10.1.1.3 step 4 */
Stephan Mueller8c987162014-06-28 21:58:24 +0200892 ret = drbg_hash_df(drbg, drbg->C, drbg_statelen(drbg), &datalist2);
Stephan Mueller541af942014-05-31 15:44:17 +0200893
894out:
895 memset(drbg->scratchpad, 0, drbg_statelen(drbg));
896 return ret;
897}
898
899/* processing of additional information string for Hash DRBG */
900static int drbg_hash_process_addtl(struct drbg_state *drbg,
Stephan Mueller27e4de22014-07-06 02:25:36 +0200901 struct list_head *addtl)
Stephan Mueller541af942014-05-31 15:44:17 +0200902{
903 int ret = 0;
904 struct drbg_string data1, data2;
Stephan Mueller8c987162014-06-28 21:58:24 +0200905 LIST_HEAD(datalist);
Stephan Mueller541af942014-05-31 15:44:17 +0200906 unsigned char prefix = DRBG_PREFIX2;
907
908 /* this is value w as per documentation */
909 memset(drbg->scratchpad, 0, drbg_blocklen(drbg));
910
911 /* 10.1.1.4 step 2 */
Stephan Mueller27e4de22014-07-06 02:25:36 +0200912 if (!addtl || list_empty(addtl))
Stephan Mueller541af942014-05-31 15:44:17 +0200913 return 0;
914
915 /* 10.1.1.4 step 2a */
916 drbg_string_fill(&data1, &prefix, 1);
917 drbg_string_fill(&data2, drbg->V, drbg_statelen(drbg));
Stephan Mueller8c987162014-06-28 21:58:24 +0200918 list_add_tail(&data1.list, &datalist);
919 list_add_tail(&data2.list, &datalist);
Stephan Mueller27e4de22014-07-06 02:25:36 +0200920 list_splice_tail(addtl, &datalist);
Stephan Mueller8c987162014-06-28 21:58:24 +0200921 ret = drbg_kcapi_hash(drbg, NULL, drbg->scratchpad, &datalist);
Stephan Mueller541af942014-05-31 15:44:17 +0200922 if (ret)
923 goto out;
924
925 /* 10.1.1.4 step 2b */
926 drbg_add_buf(drbg->V, drbg_statelen(drbg),
927 drbg->scratchpad, drbg_blocklen(drbg));
928
929out:
930 memset(drbg->scratchpad, 0, drbg_blocklen(drbg));
931 return ret;
932}
933
934/* Hashgen defined in 10.1.1.4 */
935static int drbg_hash_hashgen(struct drbg_state *drbg,
936 unsigned char *buf,
937 unsigned int buflen)
938{
939 int len = 0;
940 int ret = 0;
941 unsigned char *src = drbg->scratchpad;
942 unsigned char *dst = drbg->scratchpad + drbg_statelen(drbg);
943 struct drbg_string data;
Stephan Mueller8c987162014-06-28 21:58:24 +0200944 LIST_HEAD(datalist);
Stephan Mueller541af942014-05-31 15:44:17 +0200945 unsigned char prefix = DRBG_PREFIX1;
946
947 memset(src, 0, drbg_statelen(drbg));
948 memset(dst, 0, drbg_blocklen(drbg));
949
950 /* 10.1.1.4 step hashgen 2 */
951 memcpy(src, drbg->V, drbg_statelen(drbg));
952
953 drbg_string_fill(&data, src, drbg_statelen(drbg));
Stephan Mueller8c987162014-06-28 21:58:24 +0200954 list_add_tail(&data.list, &datalist);
Stephan Mueller541af942014-05-31 15:44:17 +0200955 while (len < buflen) {
956 unsigned int outlen = 0;
957 /* 10.1.1.4 step hashgen 4.1 */
Stephan Mueller8c987162014-06-28 21:58:24 +0200958 ret = drbg_kcapi_hash(drbg, NULL, dst, &datalist);
Stephan Mueller541af942014-05-31 15:44:17 +0200959 if (ret) {
960 len = ret;
961 goto out;
962 }
963 outlen = (drbg_blocklen(drbg) < (buflen - len)) ?
964 drbg_blocklen(drbg) : (buflen - len);
965 if (!drbg_fips_continuous_test(drbg, dst)) {
966 drbg_add_buf(src, drbg_statelen(drbg), &prefix, 1);
967 continue;
968 }
969 /* 10.1.1.4 step hashgen 4.2 */
970 memcpy(buf + len, dst, outlen);
971 len += outlen;
972 /* 10.1.1.4 hashgen step 4.3 */
973 if (len < buflen)
974 drbg_add_buf(src, drbg_statelen(drbg), &prefix, 1);
975 }
976
977out:
978 memset(drbg->scratchpad, 0,
979 (drbg_statelen(drbg) + drbg_blocklen(drbg)));
980 return len;
981}
982
983/* generate function for Hash DRBG as defined in 10.1.1.4 */
984static int drbg_hash_generate(struct drbg_state *drbg,
985 unsigned char *buf, unsigned int buflen,
Stephan Mueller27e4de22014-07-06 02:25:36 +0200986 struct list_head *addtl)
Stephan Mueller541af942014-05-31 15:44:17 +0200987{
988 int len = 0;
989 int ret = 0;
Stephan Mueller72f3e002014-08-17 17:37:34 +0200990 union {
991 unsigned char req[8];
Stephan Mueller7c8ae032014-08-26 09:32:24 +0200992 __be64 req_int;
Stephan Mueller72f3e002014-08-17 17:37:34 +0200993 } u;
Stephan Mueller541af942014-05-31 15:44:17 +0200994 unsigned char prefix = DRBG_PREFIX3;
995 struct drbg_string data1, data2;
Stephan Mueller8c987162014-06-28 21:58:24 +0200996 LIST_HEAD(datalist);
Stephan Mueller541af942014-05-31 15:44:17 +0200997
998 /* 10.1.1.4 step 2 */
999 ret = drbg_hash_process_addtl(drbg, addtl);
1000 if (ret)
1001 return ret;
1002 /* 10.1.1.4 step 3 */
1003 len = drbg_hash_hashgen(drbg, buf, buflen);
1004
1005 /* this is the value H as documented in 10.1.1.4 */
1006 memset(drbg->scratchpad, 0, drbg_blocklen(drbg));
1007 /* 10.1.1.4 step 4 */
1008 drbg_string_fill(&data1, &prefix, 1);
Stephan Mueller8c987162014-06-28 21:58:24 +02001009 list_add_tail(&data1.list, &datalist);
Stephan Mueller541af942014-05-31 15:44:17 +02001010 drbg_string_fill(&data2, drbg->V, drbg_statelen(drbg));
Stephan Mueller8c987162014-06-28 21:58:24 +02001011 list_add_tail(&data2.list, &datalist);
1012 ret = drbg_kcapi_hash(drbg, NULL, drbg->scratchpad, &datalist);
Stephan Mueller541af942014-05-31 15:44:17 +02001013 if (ret) {
1014 len = ret;
1015 goto out;
1016 }
1017
1018 /* 10.1.1.4 step 5 */
1019 drbg_add_buf(drbg->V, drbg_statelen(drbg),
1020 drbg->scratchpad, drbg_blocklen(drbg));
1021 drbg_add_buf(drbg->V, drbg_statelen(drbg),
1022 drbg->C, drbg_statelen(drbg));
Stephan Mueller72f3e002014-08-17 17:37:34 +02001023 u.req_int = cpu_to_be64(drbg->reseed_ctr);
1024 drbg_add_buf(drbg->V, drbg_statelen(drbg), u.req, 8);
Stephan Mueller541af942014-05-31 15:44:17 +02001025
1026out:
1027 memset(drbg->scratchpad, 0, drbg_blocklen(drbg));
1028 return len;
1029}
1030
1031/*
1032 * scratchpad usage: as update and generate are used isolated, both
1033 * can use the scratchpad
1034 */
1035static struct drbg_state_ops drbg_hash_ops = {
1036 .update = drbg_hash_update,
1037 .generate = drbg_hash_generate,
1038 .crypto_init = drbg_init_hash_kernel,
1039 .crypto_fini = drbg_fini_hash_kernel,
1040};
1041#endif /* CONFIG_CRYPTO_DRBG_HASH */
1042
1043/******************************************************************
1044 * Functions common for DRBG implementations
1045 ******************************************************************/
1046
1047/*
1048 * Seeding or reseeding of the DRBG
1049 *
1050 * @drbg: DRBG state struct
1051 * @pers: personalization / additional information buffer
1052 * @reseed: 0 for initial seed process, 1 for reseeding
1053 *
1054 * return:
1055 * 0 on success
1056 * error value otherwise
1057 */
1058static int drbg_seed(struct drbg_state *drbg, struct drbg_string *pers,
1059 bool reseed)
1060{
1061 int ret = 0;
1062 unsigned char *entropy = NULL;
1063 size_t entropylen = 0;
1064 struct drbg_string data1;
Stephan Mueller8c987162014-06-28 21:58:24 +02001065 LIST_HEAD(seedlist);
Stephan Mueller541af942014-05-31 15:44:17 +02001066
1067 /* 9.1 / 9.2 / 9.3.1 step 3 */
1068 if (pers && pers->len > (drbg_max_addtl(drbg))) {
Stephan Muellera9089572014-07-06 02:24:03 +02001069 pr_devel("DRBG: personalization string too long %zu\n",
Stephan Mueller541af942014-05-31 15:44:17 +02001070 pers->len);
1071 return -EINVAL;
1072 }
1073
1074 if (drbg->test_data && drbg->test_data->testentropy) {
1075 drbg_string_fill(&data1, drbg->test_data->testentropy->buf,
1076 drbg->test_data->testentropy->len);
1077 pr_devel("DRBG: using test entropy\n");
1078 } else {
1079 /*
1080 * Gather entropy equal to the security strength of the DRBG.
1081 * With a derivation function, a nonce is required in addition
1082 * to the entropy. A nonce must be at least 1/2 of the security
1083 * strength of the DRBG in size. Thus, entropy * nonce is 3/2
1084 * of the strength. The consideration of a nonce is only
1085 * applicable during initial seeding.
1086 */
1087 entropylen = drbg_sec_strength(drbg->core->flags);
1088 if (!entropylen)
1089 return -EFAULT;
1090 if (!reseed)
1091 entropylen = ((entropylen + 1) / 2) * 3;
1092 pr_devel("DRBG: (re)seeding with %zu bytes of entropy\n",
1093 entropylen);
1094 entropy = kzalloc(entropylen, GFP_KERNEL);
1095 if (!entropy)
1096 return -ENOMEM;
1097 get_random_bytes(entropy, entropylen);
1098 drbg_string_fill(&data1, entropy, entropylen);
1099 }
Stephan Mueller8c987162014-06-28 21:58:24 +02001100 list_add_tail(&data1.list, &seedlist);
Stephan Mueller541af942014-05-31 15:44:17 +02001101
1102 /*
1103 * concatenation of entropy with personalization str / addtl input)
1104 * the variable pers is directly handed in by the caller, so check its
1105 * contents whether it is appropriate
1106 */
Stephan Mueller8c987162014-06-28 21:58:24 +02001107 if (pers && pers->buf && 0 < pers->len) {
1108 list_add_tail(&pers->list, &seedlist);
Stephan Mueller541af942014-05-31 15:44:17 +02001109 pr_devel("DRBG: using personalization string\n");
1110 }
1111
Stephan Muellere6c02442014-08-17 17:39:31 +02001112 if (!reseed) {
1113 memset(drbg->V, 0, drbg_statelen(drbg));
1114 memset(drbg->C, 0, drbg_statelen(drbg));
1115 }
1116
Stephan Mueller8c987162014-06-28 21:58:24 +02001117 ret = drbg->d_ops->update(drbg, &seedlist, reseed);
Stephan Mueller541af942014-05-31 15:44:17 +02001118 if (ret)
1119 goto out;
1120
1121 drbg->seeded = true;
1122 /* 10.1.1.2 / 10.1.1.3 step 5 */
1123 drbg->reseed_ctr = 1;
1124
1125out:
Stephan Mueller46f64f62014-08-17 17:37:59 +02001126 kzfree(entropy);
Stephan Mueller541af942014-05-31 15:44:17 +02001127 return ret;
1128}
1129
1130/* Free all substructures in a DRBG state without the DRBG state structure */
1131static inline void drbg_dealloc_state(struct drbg_state *drbg)
1132{
1133 if (!drbg)
1134 return;
Stephan Mueller46f64f62014-08-17 17:37:59 +02001135 kzfree(drbg->V);
Stephan Mueller541af942014-05-31 15:44:17 +02001136 drbg->V = NULL;
Stephan Mueller46f64f62014-08-17 17:37:59 +02001137 kzfree(drbg->C);
Stephan Mueller541af942014-05-31 15:44:17 +02001138 drbg->C = NULL;
Stephan Mueller46f64f62014-08-17 17:37:59 +02001139 kzfree(drbg->scratchpad);
Stephan Mueller541af942014-05-31 15:44:17 +02001140 drbg->scratchpad = NULL;
1141 drbg->reseed_ctr = 0;
1142#ifdef CONFIG_CRYPTO_FIPS
Stephan Mueller46f64f62014-08-17 17:37:59 +02001143 kzfree(drbg->prev);
Stephan Mueller541af942014-05-31 15:44:17 +02001144 drbg->prev = NULL;
1145 drbg->fips_primed = false;
1146#endif
1147}
1148
1149/*
1150 * Allocate all sub-structures for a DRBG state.
1151 * The DRBG state structure must already be allocated.
1152 */
1153static inline int drbg_alloc_state(struct drbg_state *drbg)
1154{
1155 int ret = -ENOMEM;
1156 unsigned int sb_size = 0;
1157
Stephan Muellere6c02442014-08-17 17:39:31 +02001158 drbg->V = kmalloc(drbg_statelen(drbg), GFP_KERNEL);
Stephan Mueller541af942014-05-31 15:44:17 +02001159 if (!drbg->V)
1160 goto err;
Stephan Muellere6c02442014-08-17 17:39:31 +02001161 drbg->C = kmalloc(drbg_statelen(drbg), GFP_KERNEL);
Stephan Mueller541af942014-05-31 15:44:17 +02001162 if (!drbg->C)
1163 goto err;
1164#ifdef CONFIG_CRYPTO_FIPS
Stephan Muellere6c02442014-08-17 17:39:31 +02001165 drbg->prev = kmalloc(drbg_blocklen(drbg), GFP_KERNEL);
Stephan Mueller541af942014-05-31 15:44:17 +02001166 if (!drbg->prev)
1167 goto err;
1168 drbg->fips_primed = false;
1169#endif
1170 /* scratchpad is only generated for CTR and Hash */
1171 if (drbg->core->flags & DRBG_HMAC)
1172 sb_size = 0;
1173 else if (drbg->core->flags & DRBG_CTR)
1174 sb_size = drbg_statelen(drbg) + drbg_blocklen(drbg) + /* temp */
1175 drbg_statelen(drbg) + /* df_data */
1176 drbg_blocklen(drbg) + /* pad */
1177 drbg_blocklen(drbg) + /* iv */
Stephan Mueller8fecaad2014-07-01 17:08:48 +02001178 drbg_statelen(drbg) + drbg_blocklen(drbg); /* temp */
Stephan Mueller541af942014-05-31 15:44:17 +02001179 else
1180 sb_size = drbg_statelen(drbg) + drbg_blocklen(drbg);
1181
1182 if (0 < sb_size) {
1183 drbg->scratchpad = kzalloc(sb_size, GFP_KERNEL);
1184 if (!drbg->scratchpad)
1185 goto err;
1186 }
1187 spin_lock_init(&drbg->drbg_lock);
1188 return 0;
1189
1190err:
1191 drbg_dealloc_state(drbg);
1192 return ret;
1193}
1194
1195/*
1196 * Strategy to avoid holding long term locks: generate a shadow copy of DRBG
1197 * and perform all operations on this shadow copy. After finishing, restore
1198 * the updated state of the shadow copy into original drbg state. This way,
1199 * only the read and write operations of the original drbg state must be
1200 * locked
1201 */
1202static inline void drbg_copy_drbg(struct drbg_state *src,
1203 struct drbg_state *dst)
1204{
1205 if (!src || !dst)
1206 return;
1207 memcpy(dst->V, src->V, drbg_statelen(src));
1208 memcpy(dst->C, src->C, drbg_statelen(src));
1209 dst->reseed_ctr = src->reseed_ctr;
1210 dst->seeded = src->seeded;
1211 dst->pr = src->pr;
1212#ifdef CONFIG_CRYPTO_FIPS
1213 dst->fips_primed = src->fips_primed;
1214 memcpy(dst->prev, src->prev, drbg_blocklen(src));
1215#endif
1216 /*
1217 * Not copied:
1218 * scratchpad is initialized drbg_alloc_state;
1219 * priv_data is initialized with call to crypto_init;
1220 * d_ops and core are set outside, as these parameters are const;
1221 * test_data is set outside to prevent it being copied back.
1222 */
1223}
1224
1225static int drbg_make_shadow(struct drbg_state *drbg, struct drbg_state **shadow)
1226{
1227 int ret = -ENOMEM;
1228 struct drbg_state *tmp = NULL;
1229
Stephan Mueller541af942014-05-31 15:44:17 +02001230 tmp = kzalloc(sizeof(struct drbg_state), GFP_KERNEL);
1231 if (!tmp)
1232 return -ENOMEM;
1233
1234 /* read-only data as they are defined as const, no lock needed */
1235 tmp->core = drbg->core;
1236 tmp->d_ops = drbg->d_ops;
1237
1238 ret = drbg_alloc_state(tmp);
1239 if (ret)
1240 goto err;
1241
1242 spin_lock_bh(&drbg->drbg_lock);
1243 drbg_copy_drbg(drbg, tmp);
1244 /* only make a link to the test buffer, as we only read that data */
1245 tmp->test_data = drbg->test_data;
1246 spin_unlock_bh(&drbg->drbg_lock);
1247 *shadow = tmp;
1248 return 0;
1249
1250err:
Stephan Mueller46f64f62014-08-17 17:37:59 +02001251 kzfree(tmp);
Stephan Mueller541af942014-05-31 15:44:17 +02001252 return ret;
1253}
1254
1255static void drbg_restore_shadow(struct drbg_state *drbg,
1256 struct drbg_state **shadow)
1257{
1258 struct drbg_state *tmp = *shadow;
1259
1260 spin_lock_bh(&drbg->drbg_lock);
1261 drbg_copy_drbg(tmp, drbg);
1262 spin_unlock_bh(&drbg->drbg_lock);
1263 drbg_dealloc_state(tmp);
1264 kzfree(tmp);
1265 *shadow = NULL;
1266}
1267
1268/*************************************************************************
1269 * DRBG interface functions
1270 *************************************************************************/
1271
1272/*
1273 * DRBG generate function as required by SP800-90A - this function
1274 * generates random numbers
1275 *
1276 * @drbg DRBG state handle
1277 * @buf Buffer where to store the random numbers -- the buffer must already
1278 * be pre-allocated by caller
1279 * @buflen Length of output buffer - this value defines the number of random
1280 * bytes pulled from DRBG
1281 * @addtl Additional input that is mixed into state, may be NULL -- note
1282 * the entropy is pulled by the DRBG internally unconditionally
1283 * as defined in SP800-90A. The additional input is mixed into
1284 * the state in addition to the pulled entropy.
1285 *
1286 * return: generated number of bytes
1287 */
1288static int drbg_generate(struct drbg_state *drbg,
1289 unsigned char *buf, unsigned int buflen,
1290 struct drbg_string *addtl)
1291{
1292 int len = 0;
1293 struct drbg_state *shadow = NULL;
Stephan Mueller27e4de22014-07-06 02:25:36 +02001294 LIST_HEAD(addtllist);
1295 struct drbg_string timestamp;
1296 union {
1297 cycles_t cycles;
1298 unsigned char char_cycles[sizeof(cycles_t)];
1299 } now;
Stephan Mueller541af942014-05-31 15:44:17 +02001300
1301 if (0 == buflen || !buf) {
1302 pr_devel("DRBG: no output buffer provided\n");
1303 return -EINVAL;
1304 }
1305 if (addtl && NULL == addtl->buf && 0 < addtl->len) {
1306 pr_devel("DRBG: wrong format of additional information\n");
1307 return -EINVAL;
1308 }
1309
1310 len = drbg_make_shadow(drbg, &shadow);
1311 if (len) {
1312 pr_devel("DRBG: shadow copy cannot be generated\n");
1313 return len;
1314 }
1315
1316 /* 9.3.1 step 2 */
1317 len = -EINVAL;
1318 if (buflen > (drbg_max_request_bytes(shadow))) {
1319 pr_devel("DRBG: requested random numbers too large %u\n",
1320 buflen);
1321 goto err;
1322 }
1323
1324 /* 9.3.1 step 3 is implicit with the chosen DRBG */
1325
1326 /* 9.3.1 step 4 */
1327 if (addtl && addtl->len > (drbg_max_addtl(shadow))) {
1328 pr_devel("DRBG: additional information string too long %zu\n",
1329 addtl->len);
1330 goto err;
1331 }
1332 /* 9.3.1 step 5 is implicit with the chosen DRBG */
1333
1334 /*
1335 * 9.3.1 step 6 and 9 supplemented by 9.3.2 step c is implemented
1336 * here. The spec is a bit convoluted here, we make it simpler.
1337 */
1338 if ((drbg_max_requests(shadow)) < shadow->reseed_ctr)
1339 shadow->seeded = false;
1340
1341 /* allocate cipher handle */
Stephan Mueller45943a52014-08-17 17:38:29 +02001342 len = shadow->d_ops->crypto_init(shadow);
1343 if (len)
1344 goto err;
Stephan Mueller541af942014-05-31 15:44:17 +02001345
1346 if (shadow->pr || !shadow->seeded) {
1347 pr_devel("DRBG: reseeding before generation (prediction "
1348 "resistance: %s, state %s)\n",
1349 drbg->pr ? "true" : "false",
1350 drbg->seeded ? "seeded" : "unseeded");
1351 /* 9.3.1 steps 7.1 through 7.3 */
1352 len = drbg_seed(shadow, addtl, true);
1353 if (len)
1354 goto err;
1355 /* 9.3.1 step 7.4 */
1356 addtl = NULL;
1357 }
Stephan Mueller27e4de22014-07-06 02:25:36 +02001358
1359 /*
1360 * Mix the time stamp into the DRBG state if the DRBG is not in
1361 * test mode. If there are two callers invoking the DRBG at the same
1362 * time, i.e. before the first caller merges its shadow state back,
1363 * both callers would obtain the same random number stream without
1364 * changing the state here.
1365 */
1366 if (!drbg->test_data) {
1367 now.cycles = random_get_entropy();
1368 drbg_string_fill(&timestamp, now.char_cycles, sizeof(cycles_t));
1369 list_add_tail(&timestamp.list, &addtllist);
1370 }
1371 if (addtl && 0 < addtl->len)
1372 list_add_tail(&addtl->list, &addtllist);
Stephan Mueller541af942014-05-31 15:44:17 +02001373 /* 9.3.1 step 8 and 10 */
Stephan Mueller27e4de22014-07-06 02:25:36 +02001374 len = shadow->d_ops->generate(shadow, buf, buflen, &addtllist);
Stephan Mueller541af942014-05-31 15:44:17 +02001375
1376 /* 10.1.1.4 step 6, 10.1.2.5 step 7, 10.2.1.5.2 step 7 */
1377 shadow->reseed_ctr++;
1378 if (0 >= len)
1379 goto err;
1380
1381 /*
1382 * Section 11.3.3 requires to re-perform self tests after some
1383 * generated random numbers. The chosen value after which self
1384 * test is performed is arbitrary, but it should be reasonable.
1385 * However, we do not perform the self tests because of the following
1386 * reasons: it is mathematically impossible that the initial self tests
1387 * were successfully and the following are not. If the initial would
1388 * pass and the following would not, the kernel integrity is violated.
1389 * In this case, the entire kernel operation is questionable and it
1390 * is unlikely that the integrity violation only affects the
1391 * correct operation of the DRBG.
1392 *
1393 * Albeit the following code is commented out, it is provided in
1394 * case somebody has a need to implement the test of 11.3.3.
1395 */
1396#if 0
1397 if (shadow->reseed_ctr && !(shadow->reseed_ctr % 4096)) {
1398 int err = 0;
1399 pr_devel("DRBG: start to perform self test\n");
1400 if (drbg->core->flags & DRBG_HMAC)
1401 err = alg_test("drbg_pr_hmac_sha256",
1402 "drbg_pr_hmac_sha256", 0, 0);
1403 else if (drbg->core->flags & DRBG_CTR)
1404 err = alg_test("drbg_pr_ctr_aes128",
1405 "drbg_pr_ctr_aes128", 0, 0);
1406 else
1407 err = alg_test("drbg_pr_sha256",
1408 "drbg_pr_sha256", 0, 0);
1409 if (err) {
1410 pr_err("DRBG: periodical self test failed\n");
1411 /*
1412 * uninstantiate implies that from now on, only errors
1413 * are returned when reusing this DRBG cipher handle
1414 */
1415 drbg_uninstantiate(drbg);
1416 drbg_dealloc_state(shadow);
1417 kzfree(shadow);
1418 return 0;
1419 } else {
1420 pr_devel("DRBG: self test successful\n");
1421 }
1422 }
1423#endif
1424
1425err:
Stephan Mueller45943a52014-08-17 17:38:29 +02001426 shadow->d_ops->crypto_fini(shadow);
Stephan Mueller541af942014-05-31 15:44:17 +02001427 drbg_restore_shadow(drbg, &shadow);
1428 return len;
1429}
1430
1431/*
1432 * Wrapper around drbg_generate which can pull arbitrary long strings
1433 * from the DRBG without hitting the maximum request limitation.
1434 *
1435 * Parameters: see drbg_generate
1436 * Return codes: see drbg_generate -- if one drbg_generate request fails,
1437 * the entire drbg_generate_long request fails
1438 */
1439static int drbg_generate_long(struct drbg_state *drbg,
1440 unsigned char *buf, unsigned int buflen,
1441 struct drbg_string *addtl)
1442{
1443 int len = 0;
1444 unsigned int slice = 0;
1445 do {
1446 int tmplen = 0;
1447 unsigned int chunk = 0;
1448 slice = ((buflen - len) / drbg_max_request_bytes(drbg));
1449 chunk = slice ? drbg_max_request_bytes(drbg) : (buflen - len);
1450 tmplen = drbg_generate(drbg, buf + len, chunk, addtl);
1451 if (0 >= tmplen)
1452 return tmplen;
1453 len += tmplen;
Stephan Muellerce5481d2014-07-31 21:47:33 +02001454 } while (slice > 0 && (len < buflen));
Stephan Mueller541af942014-05-31 15:44:17 +02001455 return len;
1456}
1457
1458/*
1459 * DRBG instantiation function as required by SP800-90A - this function
1460 * sets up the DRBG handle, performs the initial seeding and all sanity
1461 * checks required by SP800-90A
1462 *
1463 * @drbg memory of state -- if NULL, new memory is allocated
1464 * @pers Personalization string that is mixed into state, may be NULL -- note
1465 * the entropy is pulled by the DRBG internally unconditionally
1466 * as defined in SP800-90A. The additional input is mixed into
1467 * the state in addition to the pulled entropy.
1468 * @coreref reference to core
1469 * @pr prediction resistance enabled
1470 *
1471 * return
1472 * 0 on success
1473 * error value otherwise
1474 */
1475static int drbg_instantiate(struct drbg_state *drbg, struct drbg_string *pers,
1476 int coreref, bool pr)
1477{
1478 int ret = -ENOMEM;
1479
1480 pr_devel("DRBG: Initializing DRBG core %d with prediction resistance "
1481 "%s\n", coreref, pr ? "enabled" : "disabled");
1482 drbg->core = &drbg_cores[coreref];
1483 drbg->pr = pr;
1484 drbg->seeded = false;
1485 switch (drbg->core->flags & DRBG_TYPE_MASK) {
1486#ifdef CONFIG_CRYPTO_DRBG_HMAC
1487 case DRBG_HMAC:
1488 drbg->d_ops = &drbg_hmac_ops;
1489 break;
1490#endif /* CONFIG_CRYPTO_DRBG_HMAC */
1491#ifdef CONFIG_CRYPTO_DRBG_HASH
1492 case DRBG_HASH:
1493 drbg->d_ops = &drbg_hash_ops;
1494 break;
1495#endif /* CONFIG_CRYPTO_DRBG_HASH */
1496#ifdef CONFIG_CRYPTO_DRBG_CTR
1497 case DRBG_CTR:
1498 drbg->d_ops = &drbg_ctr_ops;
1499 break;
1500#endif /* CONFIG_CRYPTO_DRBG_CTR */
1501 default:
1502 return -EOPNOTSUPP;
1503 }
1504
1505 /* 9.1 step 1 is implicit with the selected DRBG type */
1506
1507 /*
1508 * 9.1 step 2 is implicit as caller can select prediction resistance
1509 * and the flag is copied into drbg->flags --
1510 * all DRBG types support prediction resistance
1511 */
1512
1513 /* 9.1 step 4 is implicit in drbg_sec_strength */
1514
1515 ret = drbg_alloc_state(drbg);
1516 if (ret)
1517 return ret;
1518
1519 ret = -EFAULT;
Stephan Mueller45943a52014-08-17 17:38:29 +02001520 if (drbg->d_ops->crypto_init(drbg))
Stephan Mueller541af942014-05-31 15:44:17 +02001521 goto err;
1522 ret = drbg_seed(drbg, pers, false);
Stephan Mueller45943a52014-08-17 17:38:29 +02001523 drbg->d_ops->crypto_fini(drbg);
Stephan Mueller541af942014-05-31 15:44:17 +02001524 if (ret)
1525 goto err;
1526
1527 return 0;
1528
1529err:
1530 drbg_dealloc_state(drbg);
1531 return ret;
1532}
1533
1534/*
1535 * DRBG uninstantiate function as required by SP800-90A - this function
1536 * frees all buffers and the DRBG handle
1537 *
1538 * @drbg DRBG state handle
1539 *
1540 * return
1541 * 0 on success
1542 */
1543static int drbg_uninstantiate(struct drbg_state *drbg)
1544{
1545 spin_lock_bh(&drbg->drbg_lock);
1546 drbg_dealloc_state(drbg);
1547 /* no scrubbing of test_data -- this shall survive an uninstantiate */
1548 spin_unlock_bh(&drbg->drbg_lock);
1549 return 0;
1550}
1551
1552/*
1553 * Helper function for setting the test data in the DRBG
1554 *
1555 * @drbg DRBG state handle
1556 * @test_data test data to sets
1557 */
1558static inline void drbg_set_testdata(struct drbg_state *drbg,
1559 struct drbg_test_data *test_data)
1560{
1561 if (!test_data || !test_data->testentropy)
1562 return;
1563 spin_lock_bh(&drbg->drbg_lock);
1564 drbg->test_data = test_data;
1565 spin_unlock_bh(&drbg->drbg_lock);
1566}
1567
1568/***************************************************************
1569 * Kernel crypto API cipher invocations requested by DRBG
1570 ***************************************************************/
1571
1572#if defined(CONFIG_CRYPTO_DRBG_HASH) || defined(CONFIG_CRYPTO_DRBG_HMAC)
1573struct sdesc {
1574 struct shash_desc shash;
1575 char ctx[];
1576};
1577
1578static int drbg_init_hash_kernel(struct drbg_state *drbg)
1579{
1580 struct sdesc *sdesc;
1581 struct crypto_shash *tfm;
1582
1583 tfm = crypto_alloc_shash(drbg->core->backend_cra_name, 0, 0);
1584 if (IS_ERR(tfm)) {
1585 pr_info("DRBG: could not allocate digest TFM handle\n");
1586 return PTR_ERR(tfm);
1587 }
1588 BUG_ON(drbg_blocklen(drbg) != crypto_shash_digestsize(tfm));
1589 sdesc = kzalloc(sizeof(struct shash_desc) + crypto_shash_descsize(tfm),
1590 GFP_KERNEL);
1591 if (!sdesc) {
1592 crypto_free_shash(tfm);
1593 return -ENOMEM;
1594 }
1595
1596 sdesc->shash.tfm = tfm;
1597 sdesc->shash.flags = 0;
1598 drbg->priv_data = sdesc;
1599 return 0;
1600}
1601
1602static int drbg_fini_hash_kernel(struct drbg_state *drbg)
1603{
1604 struct sdesc *sdesc = (struct sdesc *)drbg->priv_data;
1605 if (sdesc) {
1606 crypto_free_shash(sdesc->shash.tfm);
1607 kzfree(sdesc);
1608 }
1609 drbg->priv_data = NULL;
1610 return 0;
1611}
1612
1613static int drbg_kcapi_hash(struct drbg_state *drbg, const unsigned char *key,
Stephan Mueller8c987162014-06-28 21:58:24 +02001614 unsigned char *outval, const struct list_head *in)
Stephan Mueller541af942014-05-31 15:44:17 +02001615{
1616 struct sdesc *sdesc = (struct sdesc *)drbg->priv_data;
Stephan Mueller8c987162014-06-28 21:58:24 +02001617 struct drbg_string *input = NULL;
Stephan Mueller541af942014-05-31 15:44:17 +02001618
1619 if (key)
1620 crypto_shash_setkey(sdesc->shash.tfm, key, drbg_statelen(drbg));
1621 crypto_shash_init(&sdesc->shash);
Stephan Mueller8c987162014-06-28 21:58:24 +02001622 list_for_each_entry(input, in, list)
1623 crypto_shash_update(&sdesc->shash, input->buf, input->len);
Stephan Mueller541af942014-05-31 15:44:17 +02001624 return crypto_shash_final(&sdesc->shash, outval);
1625}
1626#endif /* (CONFIG_CRYPTO_DRBG_HASH || CONFIG_CRYPTO_DRBG_HMAC) */
1627
1628#ifdef CONFIG_CRYPTO_DRBG_CTR
1629static int drbg_init_sym_kernel(struct drbg_state *drbg)
1630{
1631 int ret = 0;
1632 struct crypto_blkcipher *tfm;
1633
1634 tfm = crypto_alloc_blkcipher(drbg->core->backend_cra_name, 0, 0);
1635 if (IS_ERR(tfm)) {
1636 pr_info("DRBG: could not allocate cipher TFM handle\n");
1637 return PTR_ERR(tfm);
1638 }
1639 BUG_ON(drbg_blocklen(drbg) != crypto_blkcipher_blocksize(tfm));
1640 drbg->priv_data = tfm;
1641 return ret;
1642}
1643
1644static int drbg_fini_sym_kernel(struct drbg_state *drbg)
1645{
1646 struct crypto_blkcipher *tfm =
1647 (struct crypto_blkcipher *)drbg->priv_data;
1648 if (tfm)
1649 crypto_free_blkcipher(tfm);
1650 drbg->priv_data = NULL;
1651 return 0;
1652}
1653
1654static int drbg_kcapi_sym(struct drbg_state *drbg, const unsigned char *key,
1655 unsigned char *outval, const struct drbg_string *in)
1656{
1657 int ret = 0;
1658 struct scatterlist sg_in, sg_out;
1659 struct blkcipher_desc desc;
1660 struct crypto_blkcipher *tfm =
1661 (struct crypto_blkcipher *)drbg->priv_data;
1662
1663 desc.tfm = tfm;
1664 desc.flags = 0;
1665 crypto_blkcipher_setkey(tfm, key, (drbg_keylen(drbg)));
1666 /* there is only component in *in */
1667 sg_init_one(&sg_in, in->buf, in->len);
1668 sg_init_one(&sg_out, outval, drbg_blocklen(drbg));
1669 ret = crypto_blkcipher_encrypt(&desc, &sg_out, &sg_in, in->len);
1670
1671 return ret;
1672}
1673#endif /* CONFIG_CRYPTO_DRBG_CTR */
1674
1675/***************************************************************
1676 * Kernel crypto API interface to register DRBG
1677 ***************************************************************/
1678
1679/*
1680 * Look up the DRBG flags by given kernel crypto API cra_name
1681 * The code uses the drbg_cores definition to do this
1682 *
1683 * @cra_name kernel crypto API cra_name
1684 * @coreref reference to integer which is filled with the pointer to
1685 * the applicable core
1686 * @pr reference for setting prediction resistance
1687 *
1688 * return: flags
1689 */
1690static inline void drbg_convert_tfm_core(const char *cra_driver_name,
1691 int *coreref, bool *pr)
1692{
1693 int i = 0;
1694 size_t start = 0;
1695 int len = 0;
1696
1697 *pr = true;
1698 /* disassemble the names */
1699 if (!memcmp(cra_driver_name, "drbg_nopr_", 10)) {
1700 start = 10;
1701 *pr = false;
1702 } else if (!memcmp(cra_driver_name, "drbg_pr_", 8)) {
1703 start = 8;
1704 } else {
1705 return;
1706 }
1707
1708 /* remove the first part */
1709 len = strlen(cra_driver_name) - start;
1710 for (i = 0; ARRAY_SIZE(drbg_cores) > i; i++) {
1711 if (!memcmp(cra_driver_name + start, drbg_cores[i].cra_name,
1712 len)) {
1713 *coreref = i;
1714 return;
1715 }
1716 }
1717}
1718
1719static int drbg_kcapi_init(struct crypto_tfm *tfm)
1720{
1721 struct drbg_state *drbg = crypto_tfm_ctx(tfm);
1722 bool pr = false;
1723 int coreref = 0;
1724
Stephan Mueller4f150712014-07-06 02:25:04 +02001725 drbg_convert_tfm_core(crypto_tfm_alg_driver_name(tfm), &coreref, &pr);
Stephan Mueller541af942014-05-31 15:44:17 +02001726 /*
1727 * when personalization string is needed, the caller must call reset
1728 * and provide the personalization string as seed information
1729 */
1730 return drbg_instantiate(drbg, NULL, coreref, pr);
1731}
1732
1733static void drbg_kcapi_cleanup(struct crypto_tfm *tfm)
1734{
1735 drbg_uninstantiate(crypto_tfm_ctx(tfm));
1736}
1737
1738/*
1739 * Generate random numbers invoked by the kernel crypto API:
1740 * The API of the kernel crypto API is extended as follows:
1741 *
1742 * If dlen is larger than zero, rdata is interpreted as the output buffer
1743 * where random data is to be stored.
1744 *
1745 * If dlen is zero, rdata is interpreted as a pointer to a struct drbg_gen
1746 * which holds the additional information string that is used for the
1747 * DRBG generation process. The output buffer that is to be used to store
1748 * data is also pointed to by struct drbg_gen.
1749 */
1750static int drbg_kcapi_random(struct crypto_rng *tfm, u8 *rdata,
1751 unsigned int dlen)
1752{
1753 struct drbg_state *drbg = crypto_rng_ctx(tfm);
1754 if (0 < dlen) {
1755 return drbg_generate_long(drbg, rdata, dlen, NULL);
1756 } else {
1757 struct drbg_gen *data = (struct drbg_gen *)rdata;
Stephan Mueller8c987162014-06-28 21:58:24 +02001758 struct drbg_string addtl;
Stephan Mueller541af942014-05-31 15:44:17 +02001759 /* catch NULL pointer */
1760 if (!data)
1761 return 0;
1762 drbg_set_testdata(drbg, data->test_data);
Stephan Mueller8c987162014-06-28 21:58:24 +02001763 /* linked list variable is now local to allow modification */
1764 drbg_string_fill(&addtl, data->addtl->buf, data->addtl->len);
Stephan Mueller541af942014-05-31 15:44:17 +02001765 return drbg_generate_long(drbg, data->outbuf, data->outlen,
Stephan Mueller8c987162014-06-28 21:58:24 +02001766 &addtl);
Stephan Mueller541af942014-05-31 15:44:17 +02001767 }
1768}
1769
1770/*
1771 * Reset the DRBG invoked by the kernel crypto API
1772 * The reset implies a full re-initialization of the DRBG. Similar to the
1773 * generate function of drbg_kcapi_random, this function extends the
1774 * kernel crypto API interface with struct drbg_gen
1775 */
1776static int drbg_kcapi_reset(struct crypto_rng *tfm, u8 *seed, unsigned int slen)
1777{
1778 struct drbg_state *drbg = crypto_rng_ctx(tfm);
1779 struct crypto_tfm *tfm_base = crypto_rng_tfm(tfm);
1780 bool pr = false;
1781 struct drbg_string seed_string;
1782 int coreref = 0;
1783
1784 drbg_uninstantiate(drbg);
1785 drbg_convert_tfm_core(crypto_tfm_alg_driver_name(tfm_base), &coreref,
1786 &pr);
1787 if (0 < slen) {
1788 drbg_string_fill(&seed_string, seed, slen);
1789 return drbg_instantiate(drbg, &seed_string, coreref, pr);
1790 } else {
1791 struct drbg_gen *data = (struct drbg_gen *)seed;
1792 /* allow invocation of API call with NULL, 0 */
1793 if (!data)
1794 return drbg_instantiate(drbg, NULL, coreref, pr);
1795 drbg_set_testdata(drbg, data->test_data);
Stephan Mueller8c987162014-06-28 21:58:24 +02001796 /* linked list variable is now local to allow modification */
1797 drbg_string_fill(&seed_string, data->addtl->buf,
1798 data->addtl->len);
1799 return drbg_instantiate(drbg, &seed_string, coreref, pr);
Stephan Mueller541af942014-05-31 15:44:17 +02001800 }
1801}
1802
1803/***************************************************************
1804 * Kernel module: code to load the module
1805 ***************************************************************/
1806
1807/*
1808 * Tests as defined in 11.3.2 in addition to the cipher tests: testing
1809 * of the error handling.
1810 *
1811 * Note: testing of failing seed source as defined in 11.3.2 is not applicable
1812 * as seed source of get_random_bytes does not fail.
1813 *
1814 * Note 2: There is no sensible way of testing the reseed counter
1815 * enforcement, so skip it.
1816 */
1817static inline int __init drbg_healthcheck_sanity(void)
1818{
1819#ifdef CONFIG_CRYPTO_FIPS
1820 int len = 0;
1821#define OUTBUFLEN 16
1822 unsigned char buf[OUTBUFLEN];
1823 struct drbg_state *drbg = NULL;
1824 int ret = -EFAULT;
1825 int rc = -EFAULT;
1826 bool pr = false;
1827 int coreref = 0;
1828 struct drbg_string addtl;
1829 size_t max_addtllen, max_request_bytes;
1830
1831 /* only perform test in FIPS mode */
1832 if (!fips_enabled)
1833 return 0;
1834
1835#ifdef CONFIG_CRYPTO_DRBG_CTR
1836 drbg_convert_tfm_core("drbg_nopr_ctr_aes128", &coreref, &pr);
Stephan Muellere25e47e2014-07-06 02:23:03 +02001837#elif defined CONFIG_CRYPTO_DRBG_HASH
Stephan Mueller541af942014-05-31 15:44:17 +02001838 drbg_convert_tfm_core("drbg_nopr_sha256", &coreref, &pr);
1839#else
1840 drbg_convert_tfm_core("drbg_nopr_hmac_sha256", &coreref, &pr);
1841#endif
1842
1843 drbg = kzalloc(sizeof(struct drbg_state), GFP_KERNEL);
1844 if (!drbg)
1845 return -ENOMEM;
1846
1847 /*
1848 * if the following tests fail, it is likely that there is a buffer
1849 * overflow as buf is much smaller than the requested or provided
1850 * string lengths -- in case the error handling does not succeed
1851 * we may get an OOPS. And we want to get an OOPS as this is a
1852 * grave bug.
1853 */
1854
1855 /* get a valid instance of DRBG for following tests */
1856 ret = drbg_instantiate(drbg, NULL, coreref, pr);
1857 if (ret) {
1858 rc = ret;
1859 goto outbuf;
1860 }
1861 max_addtllen = drbg_max_addtl(drbg);
1862 max_request_bytes = drbg_max_request_bytes(drbg);
1863 drbg_string_fill(&addtl, buf, max_addtllen + 1);
1864 /* overflow addtllen with additonal info string */
1865 len = drbg_generate(drbg, buf, OUTBUFLEN, &addtl);
1866 BUG_ON(0 < len);
1867 /* overflow max_bits */
1868 len = drbg_generate(drbg, buf, (max_request_bytes + 1), NULL);
1869 BUG_ON(0 < len);
1870 drbg_uninstantiate(drbg);
1871
1872 /* overflow max addtllen with personalization string */
1873 ret = drbg_instantiate(drbg, &addtl, coreref, pr);
1874 BUG_ON(0 == ret);
Stephan Mueller541af942014-05-31 15:44:17 +02001875 /* all tests passed */
1876 rc = 0;
1877
1878 pr_devel("DRBG: Sanity tests for failure code paths successfully "
1879 "completed\n");
1880
1881 drbg_uninstantiate(drbg);
1882outbuf:
1883 kzfree(drbg);
1884 return rc;
1885#else /* CONFIG_CRYPTO_FIPS */
1886 return 0;
1887#endif /* CONFIG_CRYPTO_FIPS */
1888}
1889
1890static struct crypto_alg drbg_algs[22];
1891
1892/*
1893 * Fill the array drbg_algs used to register the different DRBGs
1894 * with the kernel crypto API. To fill the array, the information
1895 * from drbg_cores[] is used.
1896 */
1897static inline void __init drbg_fill_array(struct crypto_alg *alg,
1898 const struct drbg_core *core, int pr)
1899{
1900 int pos = 0;
1901 static int priority = 100;
1902
1903 memset(alg, 0, sizeof(struct crypto_alg));
1904 memcpy(alg->cra_name, "stdrng", 6);
1905 if (pr) {
1906 memcpy(alg->cra_driver_name, "drbg_pr_", 8);
1907 pos = 8;
1908 } else {
1909 memcpy(alg->cra_driver_name, "drbg_nopr_", 10);
1910 pos = 10;
1911 }
1912 memcpy(alg->cra_driver_name + pos, core->cra_name,
1913 strlen(core->cra_name));
1914
1915 alg->cra_priority = priority;
1916 priority++;
1917 /*
1918 * If FIPS mode enabled, the selected DRBG shall have the
1919 * highest cra_priority over other stdrng instances to ensure
1920 * it is selected.
1921 */
1922 if (fips_enabled)
1923 alg->cra_priority += 200;
1924
1925 alg->cra_flags = CRYPTO_ALG_TYPE_RNG;
1926 alg->cra_ctxsize = sizeof(struct drbg_state);
1927 alg->cra_type = &crypto_rng_type;
1928 alg->cra_module = THIS_MODULE;
1929 alg->cra_init = drbg_kcapi_init;
1930 alg->cra_exit = drbg_kcapi_cleanup;
1931 alg->cra_u.rng.rng_make_random = drbg_kcapi_random;
1932 alg->cra_u.rng.rng_reset = drbg_kcapi_reset;
1933 alg->cra_u.rng.seedsize = 0;
1934}
1935
1936static int __init drbg_init(void)
1937{
1938 unsigned int i = 0; /* pointer to drbg_algs */
1939 unsigned int j = 0; /* pointer to drbg_cores */
1940 int ret = -EFAULT;
1941
1942 ret = drbg_healthcheck_sanity();
1943 if (ret)
1944 return ret;
1945
1946 if (ARRAY_SIZE(drbg_cores) * 2 > ARRAY_SIZE(drbg_algs)) {
1947 pr_info("DRBG: Cannot register all DRBG types"
Stephan Muellera9089572014-07-06 02:24:03 +02001948 "(slots needed: %zu, slots available: %zu)\n",
Stephan Mueller541af942014-05-31 15:44:17 +02001949 ARRAY_SIZE(drbg_cores) * 2, ARRAY_SIZE(drbg_algs));
1950 return ret;
1951 }
1952
1953 /*
1954 * each DRBG definition can be used with PR and without PR, thus
1955 * we instantiate each DRBG in drbg_cores[] twice.
1956 *
1957 * As the order of placing them into the drbg_algs array matters
1958 * (the later DRBGs receive a higher cra_priority) we register the
1959 * prediction resistance DRBGs first as the should not be too
1960 * interesting.
1961 */
1962 for (j = 0; ARRAY_SIZE(drbg_cores) > j; j++, i++)
1963 drbg_fill_array(&drbg_algs[i], &drbg_cores[j], 1);
1964 for (j = 0; ARRAY_SIZE(drbg_cores) > j; j++, i++)
1965 drbg_fill_array(&drbg_algs[i], &drbg_cores[j], 0);
1966 return crypto_register_algs(drbg_algs, (ARRAY_SIZE(drbg_cores) * 2));
1967}
1968
Fengguang Wu96956ae2014-07-10 16:52:04 +08001969static void __exit drbg_exit(void)
Stephan Mueller541af942014-05-31 15:44:17 +02001970{
1971 crypto_unregister_algs(drbg_algs, (ARRAY_SIZE(drbg_cores) * 2));
1972}
1973
1974module_init(drbg_init);
1975module_exit(drbg_exit);
Stephan Muellere25e47e2014-07-06 02:23:03 +02001976#ifndef CRYPTO_DRBG_HASH_STRING
1977#define CRYPTO_DRBG_HASH_STRING ""
1978#endif
1979#ifndef CRYPTO_DRBG_HMAC_STRING
1980#define CRYPTO_DRBG_HMAC_STRING ""
1981#endif
1982#ifndef CRYPTO_DRBG_CTR_STRING
1983#define CRYPTO_DRBG_CTR_STRING ""
1984#endif
Stephan Mueller541af942014-05-31 15:44:17 +02001985MODULE_LICENSE("GPL");
1986MODULE_AUTHOR("Stephan Mueller <smueller@chronox.de>");
Stephan Muellere25e47e2014-07-06 02:23:03 +02001987MODULE_DESCRIPTION("NIST SP800-90A Deterministic Random Bit Generator (DRBG) "
1988 "using following cores: "
1989 CRYPTO_DRBG_HASH_STRING
1990 CRYPTO_DRBG_HMAC_STRING
1991 CRYPTO_DRBG_CTR_STRING);