2 * DRBG: Deterministic Random Bits Generator
3 * Based on NIST Recommended DRBG from NIST SP800-90A with the following
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
10 * Copyright Stephan Mueller <smueller@chronox.de>, 2014
12 * Redistribution and use in source and binary forms, with or without
13 * modification, are permitted provided that the following conditions
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
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.)
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
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.
51 * Usage without any additional data
52 * ---------------------------------
53 * struct crypto_rng *drng;
57 * drng = crypto_alloc_rng(drng_name, 0, 0);
58 * err = crypto_rng_get_bytes(drng, &data, DATALEN);
59 * crypto_free_rng(drng);
62 * Usage with personalization string during initialization
63 * -------------------------------------------------------
64 * struct crypto_rng *drng;
67 * struct drbg_string pers;
68 * char personalization[11] = "some-string";
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);
79 * Usage with additional information string during random number request
80 * ---------------------------------------------------------------------
81 * struct crypto_rng *drng;
84 * char addtl_string[11] = "some-string";
85 * string drbg_string addtl;
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);
95 * Usage with personalization and additional information strings
96 * -------------------------------------------------------------
97 * Just mix both scenarios above.
100 #include <crypto/drbg.h>
101 #include <linux/kernel.h>
103 /***************************************************************
104 * Backend cipher definitions available to DRBG
105 ***************************************************************/
108 * The order of the DRBG definitions here matter: every DRBG is registered
109 * as stdrng. Each DRBG receives an increasing cra_priority values the later
110 * they are defined in this array (see drbg_fill_array).
112 * HMAC DRBGs are favored over Hash DRBGs over CTR DRBGs, and
113 * the SHA256 / AES 256 over other ciphers. Thus, the favored
114 * DRBGs are the latest entries in this array.
116 static const struct drbg_core drbg_cores[] = {
117 #ifdef CONFIG_CRYPTO_DRBG_CTR
119 .flags = DRBG_CTR | DRBG_STRENGTH128,
120 .statelen = 32, /* 256 bits as defined in 10.2.1 */
121 .blocklen_bytes = 16,
122 .cra_name = "ctr_aes128",
123 .backend_cra_name = "aes",
125 .flags = DRBG_CTR | DRBG_STRENGTH192,
126 .statelen = 40, /* 320 bits as defined in 10.2.1 */
127 .blocklen_bytes = 16,
128 .cra_name = "ctr_aes192",
129 .backend_cra_name = "aes",
131 .flags = DRBG_CTR | DRBG_STRENGTH256,
132 .statelen = 48, /* 384 bits as defined in 10.2.1 */
133 .blocklen_bytes = 16,
134 .cra_name = "ctr_aes256",
135 .backend_cra_name = "aes",
137 #endif /* CONFIG_CRYPTO_DRBG_CTR */
138 #ifdef CONFIG_CRYPTO_DRBG_HASH
140 .flags = DRBG_HASH | DRBG_STRENGTH128,
141 .statelen = 55, /* 440 bits */
142 .blocklen_bytes = 20,
144 .backend_cra_name = "sha1",
146 .flags = DRBG_HASH | DRBG_STRENGTH256,
147 .statelen = 111, /* 888 bits */
148 .blocklen_bytes = 48,
149 .cra_name = "sha384",
150 .backend_cra_name = "sha384",
152 .flags = DRBG_HASH | DRBG_STRENGTH256,
153 .statelen = 111, /* 888 bits */
154 .blocklen_bytes = 64,
155 .cra_name = "sha512",
156 .backend_cra_name = "sha512",
158 .flags = DRBG_HASH | DRBG_STRENGTH256,
159 .statelen = 55, /* 440 bits */
160 .blocklen_bytes = 32,
161 .cra_name = "sha256",
162 .backend_cra_name = "sha256",
164 #endif /* CONFIG_CRYPTO_DRBG_HASH */
165 #ifdef CONFIG_CRYPTO_DRBG_HMAC
167 .flags = DRBG_HMAC | DRBG_STRENGTH128,
168 .statelen = 20, /* block length of cipher */
169 .blocklen_bytes = 20,
170 .cra_name = "hmac_sha1",
171 .backend_cra_name = "hmac(sha1)",
173 .flags = DRBG_HMAC | DRBG_STRENGTH256,
174 .statelen = 48, /* block length of cipher */
175 .blocklen_bytes = 48,
176 .cra_name = "hmac_sha384",
177 .backend_cra_name = "hmac(sha384)",
179 .flags = DRBG_HMAC | DRBG_STRENGTH256,
180 .statelen = 64, /* block length of cipher */
181 .blocklen_bytes = 64,
182 .cra_name = "hmac_sha512",
183 .backend_cra_name = "hmac(sha512)",
185 .flags = DRBG_HMAC | DRBG_STRENGTH256,
186 .statelen = 32, /* block length of cipher */
187 .blocklen_bytes = 32,
188 .cra_name = "hmac_sha256",
189 .backend_cra_name = "hmac(sha256)",
191 #endif /* CONFIG_CRYPTO_DRBG_HMAC */
194 static int drbg_uninstantiate(struct drbg_state *drbg);
196 /******************************************************************
197 * Generic helper functions
198 ******************************************************************/
201 * Return strength of DRBG according to SP800-90A section 8.4
203 * @flags DRBG flags reference
205 * Return: normalized strength in *bytes* value or 32 as default
206 * to counter programming errors
208 static inline unsigned short drbg_sec_strength(drbg_flag_t flags)
210 switch (flags & DRBG_STRENGTH_MASK) {
211 case DRBG_STRENGTH128:
213 case DRBG_STRENGTH192:
215 case DRBG_STRENGTH256:
223 * FIPS 140-2 continuous self test for the noise source
224 * The test is performed on the noise source input data. Thus, the function
225 * implicitly knows the size of the buffer to be equal to the security
228 * Note, this function disregards the nonce trailing the entropy data during
231 * drbg->drbg_mutex must have been taken.
234 * @entropy buffer of seed data to be checked
238 * -EAGAIN on when the CTRNG is not yet primed
241 static int drbg_fips_continuous_test(struct drbg_state *drbg,
242 const unsigned char *entropy)
244 unsigned short entropylen = drbg_sec_strength(drbg->core->flags);
247 if (!IS_ENABLED(CONFIG_CRYPTO_FIPS))
250 /* skip test if we test the overall system */
251 if (list_empty(&drbg->test_data.list))
253 /* only perform test in FIPS mode */
257 if (!drbg->fips_primed) {
258 /* Priming of FIPS test */
259 memcpy(drbg->prev, entropy, entropylen);
260 drbg->fips_primed = true;
261 /* priming: another round is needed */
264 ret = memcmp(drbg->prev, entropy, entropylen);
266 panic("DRBG continuous self test failed\n");
267 memcpy(drbg->prev, entropy, entropylen);
269 /* the test shall pass when the two values are not equal */
274 * Convert an integer into a byte representation of this integer.
275 * The byte representation is big-endian
277 * @val value to be converted
278 * @buf buffer holding the converted integer -- caller must ensure that
279 * buffer size is at least 32 bit
281 #if (defined(CONFIG_CRYPTO_DRBG_HASH) || defined(CONFIG_CRYPTO_DRBG_CTR))
282 static inline void drbg_cpu_to_be32(__u32 val, unsigned char *buf)
287 struct s *conversion = (struct s *) buf;
289 conversion->conv = cpu_to_be32(val);
291 #endif /* defined(CONFIG_CRYPTO_DRBG_HASH) || defined(CONFIG_CRYPTO_DRBG_CTR) */
293 /******************************************************************
294 * CTR DRBG callback functions
295 ******************************************************************/
297 #ifdef CONFIG_CRYPTO_DRBG_CTR
298 #define CRYPTO_DRBG_CTR_STRING "CTR "
299 MODULE_ALIAS_CRYPTO("drbg_pr_ctr_aes256");
300 MODULE_ALIAS_CRYPTO("drbg_nopr_ctr_aes256");
301 MODULE_ALIAS_CRYPTO("drbg_pr_ctr_aes192");
302 MODULE_ALIAS_CRYPTO("drbg_nopr_ctr_aes192");
303 MODULE_ALIAS_CRYPTO("drbg_pr_ctr_aes128");
304 MODULE_ALIAS_CRYPTO("drbg_nopr_ctr_aes128");
306 static void drbg_kcapi_symsetkey(struct drbg_state *drbg,
307 const unsigned char *key);
308 static int drbg_kcapi_sym(struct drbg_state *drbg, unsigned char *outval,
309 const struct drbg_string *in);
310 static int drbg_init_sym_kernel(struct drbg_state *drbg);
311 static int drbg_fini_sym_kernel(struct drbg_state *drbg);
312 static int drbg_kcapi_sym_ctr(struct drbg_state *drbg,
313 u8 *inbuf, u32 inbuflen,
314 u8 *outbuf, u32 outlen);
315 #define DRBG_CTR_NULL_LEN 128
316 #define DRBG_OUTSCRATCHLEN DRBG_CTR_NULL_LEN
318 /* BCC function for CTR DRBG as defined in 10.4.3 */
319 static int drbg_ctr_bcc(struct drbg_state *drbg,
320 unsigned char *out, const unsigned char *key,
321 struct list_head *in)
324 struct drbg_string *curr = NULL;
325 struct drbg_string data;
328 drbg_string_fill(&data, out, drbg_blocklen(drbg));
330 /* 10.4.3 step 2 / 4 */
331 drbg_kcapi_symsetkey(drbg, key);
332 list_for_each_entry(curr, in, list) {
333 const unsigned char *pos = curr->buf;
334 size_t len = curr->len;
335 /* 10.4.3 step 4.1 */
337 /* 10.4.3 step 4.2 */
338 if (drbg_blocklen(drbg) == cnt) {
340 ret = drbg_kcapi_sym(drbg, out, &data);
350 /* 10.4.3 step 4.2 for last block */
352 ret = drbg_kcapi_sym(drbg, out, &data);
358 * scratchpad usage: drbg_ctr_update is interlinked with drbg_ctr_df
359 * (and drbg_ctr_bcc, but this function does not need any temporary buffers),
360 * the scratchpad is used as follows:
363 * start: drbg->scratchpad
364 * length: drbg_statelen(drbg) + drbg_blocklen(drbg)
365 * note: the cipher writing into this variable works
366 * blocklen-wise. Now, when the statelen is not a multiple
367 * of blocklen, the generateion loop below "spills over"
368 * by at most blocklen. Thus, we need to give sufficient
371 * start: drbg->scratchpad +
372 * drbg_statelen(drbg) + drbg_blocklen(drbg)
373 * length: drbg_statelen(drbg)
377 * start: df_data + drbg_statelen(drbg)
378 * length: drbg_blocklen(drbg)
380 * start: pad + drbg_blocklen(drbg)
381 * length: drbg_blocklen(drbg)
383 * start: iv + drbg_blocklen(drbg)
384 * length: drbg_satelen(drbg) + drbg_blocklen(drbg)
385 * note: temp is the buffer that the BCC function operates
386 * on. BCC operates blockwise. drbg_statelen(drbg)
387 * is sufficient when the DRBG state length is a multiple
388 * of the block size. For AES192 (and maybe other ciphers)
389 * this is not correct and the length for temp is
390 * insufficient (yes, that also means for such ciphers,
391 * the final output of all BCC rounds are truncated).
392 * Therefore, add drbg_blocklen(drbg) to cover all
396 /* Derivation Function for CTR DRBG as defined in 10.4.2 */
397 static int drbg_ctr_df(struct drbg_state *drbg,
398 unsigned char *df_data, size_t bytes_to_return,
399 struct list_head *seedlist)
402 unsigned char L_N[8];
404 struct drbg_string S1, S2, S4, cipherin;
406 unsigned char *pad = df_data + drbg_statelen(drbg);
407 unsigned char *iv = pad + drbg_blocklen(drbg);
408 unsigned char *temp = iv + drbg_blocklen(drbg);
410 unsigned int templen = 0;
414 const unsigned char *K = (unsigned char *)
415 "\x00\x01\x02\x03\x04\x05\x06\x07"
416 "\x08\x09\x0a\x0b\x0c\x0d\x0e\x0f"
417 "\x10\x11\x12\x13\x14\x15\x16\x17"
418 "\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f";
420 size_t generated_len = 0;
422 struct drbg_string *seed = NULL;
424 memset(pad, 0, drbg_blocklen(drbg));
425 memset(iv, 0, drbg_blocklen(drbg));
427 /* 10.4.2 step 1 is implicit as we work byte-wise */
430 if ((512/8) < bytes_to_return)
433 /* 10.4.2 step 2 -- calculate the entire length of all input data */
434 list_for_each_entry(seed, seedlist, list)
435 inputlen += seed->len;
436 drbg_cpu_to_be32(inputlen, &L_N[0]);
439 drbg_cpu_to_be32(bytes_to_return, &L_N[4]);
441 /* 10.4.2 step 5: length is L_N, input_string, one byte, padding */
442 padlen = (inputlen + sizeof(L_N) + 1) % (drbg_blocklen(drbg));
443 /* wrap the padlen appropriately */
445 padlen = drbg_blocklen(drbg) - padlen;
447 * pad / padlen contains the 0x80 byte and the following zero bytes.
448 * As the calculated padlen value only covers the number of zero
449 * bytes, this value has to be incremented by one for the 0x80 byte.
454 /* 10.4.2 step 4 -- first fill the linked list and then order it */
455 drbg_string_fill(&S1, iv, drbg_blocklen(drbg));
456 list_add_tail(&S1.list, &bcc_list);
457 drbg_string_fill(&S2, L_N, sizeof(L_N));
458 list_add_tail(&S2.list, &bcc_list);
459 list_splice_tail(seedlist, &bcc_list);
460 drbg_string_fill(&S4, pad, padlen);
461 list_add_tail(&S4.list, &bcc_list);
464 while (templen < (drbg_keylen(drbg) + (drbg_blocklen(drbg)))) {
466 * 10.4.2 step 9.1 - the padding is implicit as the buffer
467 * holds zeros after allocation -- even the increment of i
468 * is irrelevant as the increment remains within length of i
470 drbg_cpu_to_be32(i, iv);
471 /* 10.4.2 step 9.2 -- BCC and concatenation with temp */
472 ret = drbg_ctr_bcc(drbg, temp + templen, K, &bcc_list);
475 /* 10.4.2 step 9.3 */
477 templen += drbg_blocklen(drbg);
481 X = temp + (drbg_keylen(drbg));
482 drbg_string_fill(&cipherin, X, drbg_blocklen(drbg));
484 /* 10.4.2 step 12: overwriting of outval is implemented in next step */
487 drbg_kcapi_symsetkey(drbg, temp);
488 while (generated_len < bytes_to_return) {
491 * 10.4.2 step 13.1: the truncation of the key length is
492 * implicit as the key is only drbg_blocklen in size based on
493 * the implementation of the cipher function callback
495 ret = drbg_kcapi_sym(drbg, X, &cipherin);
498 blocklen = (drbg_blocklen(drbg) <
499 (bytes_to_return - generated_len)) ?
500 drbg_blocklen(drbg) :
501 (bytes_to_return - generated_len);
502 /* 10.4.2 step 13.2 and 14 */
503 memcpy(df_data + generated_len, X, blocklen);
504 generated_len += blocklen;
510 memset(iv, 0, drbg_blocklen(drbg));
511 memset(temp, 0, drbg_statelen(drbg) + drbg_blocklen(drbg));
512 memset(pad, 0, drbg_blocklen(drbg));
517 * update function of CTR DRBG as defined in 10.2.1.2
519 * The reseed variable has an enhanced meaning compared to the update
520 * functions of the other DRBGs as follows:
521 * 0 => initial seed from initialization
522 * 1 => reseed via drbg_seed
523 * 2 => first invocation from drbg_ctr_update when addtl is present. In
524 * this case, the df_data scratchpad is not deleted so that it is
525 * available for another calls to prevent calling the DF function
527 * 3 => second invocation from drbg_ctr_update. When the update function
528 * was called with addtl, the df_data memory already contains the
529 * DFed addtl information and we do not need to call DF again.
531 static int drbg_ctr_update(struct drbg_state *drbg, struct list_head *seed,
535 /* 10.2.1.2 step 1 */
536 unsigned char *temp = drbg->scratchpad;
537 unsigned char *df_data = drbg->scratchpad + drbg_statelen(drbg) +
541 memset(df_data, 0, drbg_statelen(drbg));
545 * The DRBG uses the CTR mode of the underlying AES cipher. The
546 * CTR mode increments the counter value after the AES operation
547 * but SP800-90A requires that the counter is incremented before
548 * the AES operation. Hence, we increment it at the time we set
551 crypto_inc(drbg->V, drbg_blocklen(drbg));
553 ret = crypto_skcipher_setkey(drbg->ctr_handle, drbg->C,
559 /* 10.2.1.3.2 step 2 and 10.2.1.4.2 step 2 */
561 ret = drbg_ctr_df(drbg, df_data, drbg_statelen(drbg), seed);
566 ret = drbg_kcapi_sym_ctr(drbg, df_data, drbg_statelen(drbg),
567 temp, drbg_statelen(drbg));
571 /* 10.2.1.2 step 5 */
572 ret = crypto_skcipher_setkey(drbg->ctr_handle, temp,
576 /* 10.2.1.2 step 6 */
577 memcpy(drbg->V, temp + drbg_keylen(drbg), drbg_blocklen(drbg));
578 /* See above: increment counter by one to compensate timing of CTR op */
579 crypto_inc(drbg->V, drbg_blocklen(drbg));
583 memset(temp, 0, drbg_statelen(drbg) + drbg_blocklen(drbg));
585 memset(df_data, 0, drbg_statelen(drbg));
590 * scratchpad use: drbg_ctr_update is called independently from
591 * drbg_ctr_extract_bytes. Therefore, the scratchpad is reused
593 /* Generate function of CTR DRBG as defined in 10.2.1.5.2 */
594 static int drbg_ctr_generate(struct drbg_state *drbg,
595 unsigned char *buf, unsigned int buflen,
596 struct list_head *addtl)
599 int len = min_t(int, buflen, INT_MAX);
601 /* 10.2.1.5.2 step 2 */
602 if (addtl && !list_empty(addtl)) {
603 ret = drbg_ctr_update(drbg, addtl, 2);
608 /* 10.2.1.5.2 step 4.1 */
609 ret = drbg_kcapi_sym_ctr(drbg, drbg->ctr_null_value, DRBG_CTR_NULL_LEN,
614 /* 10.2.1.5.2 step 6 */
615 ret = drbg_ctr_update(drbg, NULL, 3);
622 static const struct drbg_state_ops drbg_ctr_ops = {
623 .update = drbg_ctr_update,
624 .generate = drbg_ctr_generate,
625 .crypto_init = drbg_init_sym_kernel,
626 .crypto_fini = drbg_fini_sym_kernel,
628 #endif /* CONFIG_CRYPTO_DRBG_CTR */
630 /******************************************************************
631 * HMAC DRBG callback functions
632 ******************************************************************/
634 #if defined(CONFIG_CRYPTO_DRBG_HASH) || defined(CONFIG_CRYPTO_DRBG_HMAC)
635 static int drbg_kcapi_hash(struct drbg_state *drbg, unsigned char *outval,
636 const struct list_head *in);
637 static void drbg_kcapi_hmacsetkey(struct drbg_state *drbg,
638 const unsigned char *key);
639 static int drbg_init_hash_kernel(struct drbg_state *drbg);
640 static int drbg_fini_hash_kernel(struct drbg_state *drbg);
641 #endif /* (CONFIG_CRYPTO_DRBG_HASH || CONFIG_CRYPTO_DRBG_HMAC) */
643 #ifdef CONFIG_CRYPTO_DRBG_HMAC
644 #define CRYPTO_DRBG_HMAC_STRING "HMAC "
645 MODULE_ALIAS_CRYPTO("drbg_pr_hmac_sha512");
646 MODULE_ALIAS_CRYPTO("drbg_nopr_hmac_sha512");
647 MODULE_ALIAS_CRYPTO("drbg_pr_hmac_sha384");
648 MODULE_ALIAS_CRYPTO("drbg_nopr_hmac_sha384");
649 MODULE_ALIAS_CRYPTO("drbg_pr_hmac_sha256");
650 MODULE_ALIAS_CRYPTO("drbg_nopr_hmac_sha256");
651 MODULE_ALIAS_CRYPTO("drbg_pr_hmac_sha1");
652 MODULE_ALIAS_CRYPTO("drbg_nopr_hmac_sha1");
654 /* update function of HMAC DRBG as defined in 10.1.2.2 */
655 static int drbg_hmac_update(struct drbg_state *drbg, struct list_head *seed,
660 struct drbg_string seed1, seed2, vdata;
662 LIST_HEAD(vdatalist);
665 /* 10.1.2.3 step 2 -- memset(0) of C is implicit with kzalloc */
666 memset(drbg->V, 1, drbg_statelen(drbg));
667 drbg_kcapi_hmacsetkey(drbg, drbg->C);
670 drbg_string_fill(&seed1, drbg->V, drbg_statelen(drbg));
671 list_add_tail(&seed1.list, &seedlist);
672 /* buffer of seed2 will be filled in for loop below with one byte */
673 drbg_string_fill(&seed2, NULL, 1);
674 list_add_tail(&seed2.list, &seedlist);
675 /* input data of seed is allowed to be NULL at this point */
677 list_splice_tail(seed, &seedlist);
679 drbg_string_fill(&vdata, drbg->V, drbg_statelen(drbg));
680 list_add_tail(&vdata.list, &vdatalist);
681 for (i = 2; 0 < i; i--) {
682 /* first round uses 0x0, second 0x1 */
683 unsigned char prefix = DRBG_PREFIX0;
685 prefix = DRBG_PREFIX1;
686 /* 10.1.2.2 step 1 and 4 -- concatenation and HMAC for key */
688 ret = drbg_kcapi_hash(drbg, drbg->C, &seedlist);
691 drbg_kcapi_hmacsetkey(drbg, drbg->C);
693 /* 10.1.2.2 step 2 and 5 -- HMAC for V */
694 ret = drbg_kcapi_hash(drbg, drbg->V, &vdatalist);
698 /* 10.1.2.2 step 3 */
706 /* generate function of HMAC DRBG as defined in 10.1.2.5 */
707 static int drbg_hmac_generate(struct drbg_state *drbg,
710 struct list_head *addtl)
714 struct drbg_string data;
717 /* 10.1.2.5 step 2 */
718 if (addtl && !list_empty(addtl)) {
719 ret = drbg_hmac_update(drbg, addtl, 1);
724 drbg_string_fill(&data, drbg->V, drbg_statelen(drbg));
725 list_add_tail(&data.list, &datalist);
726 while (len < buflen) {
727 unsigned int outlen = 0;
728 /* 10.1.2.5 step 4.1 */
729 ret = drbg_kcapi_hash(drbg, drbg->V, &datalist);
732 outlen = (drbg_blocklen(drbg) < (buflen - len)) ?
733 drbg_blocklen(drbg) : (buflen - len);
735 /* 10.1.2.5 step 4.2 */
736 memcpy(buf + len, drbg->V, outlen);
740 /* 10.1.2.5 step 6 */
741 if (addtl && !list_empty(addtl))
742 ret = drbg_hmac_update(drbg, addtl, 1);
744 ret = drbg_hmac_update(drbg, NULL, 1);
751 static const struct drbg_state_ops drbg_hmac_ops = {
752 .update = drbg_hmac_update,
753 .generate = drbg_hmac_generate,
754 .crypto_init = drbg_init_hash_kernel,
755 .crypto_fini = drbg_fini_hash_kernel,
757 #endif /* CONFIG_CRYPTO_DRBG_HMAC */
759 /******************************************************************
760 * Hash DRBG callback functions
761 ******************************************************************/
763 #ifdef CONFIG_CRYPTO_DRBG_HASH
764 #define CRYPTO_DRBG_HASH_STRING "HASH "
765 MODULE_ALIAS_CRYPTO("drbg_pr_sha512");
766 MODULE_ALIAS_CRYPTO("drbg_nopr_sha512");
767 MODULE_ALIAS_CRYPTO("drbg_pr_sha384");
768 MODULE_ALIAS_CRYPTO("drbg_nopr_sha384");
769 MODULE_ALIAS_CRYPTO("drbg_pr_sha256");
770 MODULE_ALIAS_CRYPTO("drbg_nopr_sha256");
771 MODULE_ALIAS_CRYPTO("drbg_pr_sha1");
772 MODULE_ALIAS_CRYPTO("drbg_nopr_sha1");
777 * @dst buffer to increment
780 static inline void drbg_add_buf(unsigned char *dst, size_t dstlen,
781 const unsigned char *add, size_t addlen)
783 /* implied: dstlen > addlen */
784 unsigned char *dstptr;
785 const unsigned char *addptr;
786 unsigned int remainder = 0;
789 dstptr = dst + (dstlen-1);
790 addptr = add + (addlen-1);
792 remainder += *dstptr + *addptr;
793 *dstptr = remainder & 0xff;
795 len--; dstptr--; addptr--;
797 len = dstlen - addlen;
798 while (len && remainder > 0) {
799 remainder = *dstptr + 1;
800 *dstptr = remainder & 0xff;
807 * scratchpad usage: as drbg_hash_update and drbg_hash_df are used
808 * interlinked, the scratchpad is used as follows:
810 * start: drbg->scratchpad
811 * length: drbg_statelen(drbg)
813 * start: drbg->scratchpad + drbg_statelen(drbg)
814 * length: drbg_blocklen(drbg)
816 * drbg_hash_process_addtl uses the scratchpad, but fully completes
817 * before either of the functions mentioned before are invoked. Therefore,
818 * drbg_hash_process_addtl does not need to be specifically considered.
821 /* Derivation Function for Hash DRBG as defined in 10.4.1 */
822 static int drbg_hash_df(struct drbg_state *drbg,
823 unsigned char *outval, size_t outlen,
824 struct list_head *entropylist)
828 unsigned char input[5];
829 unsigned char *tmp = drbg->scratchpad + drbg_statelen(drbg);
830 struct drbg_string data;
834 drbg_cpu_to_be32((outlen * 8), &input[1]);
836 /* 10.4.1 step 4.1 -- concatenation of data for input into hash */
837 drbg_string_fill(&data, input, 5);
838 list_add(&data.list, entropylist);
841 while (len < outlen) {
843 /* 10.4.1 step 4.1 */
844 ret = drbg_kcapi_hash(drbg, tmp, entropylist);
847 /* 10.4.1 step 4.2 */
849 blocklen = (drbg_blocklen(drbg) < (outlen - len)) ?
850 drbg_blocklen(drbg) : (outlen - len);
851 memcpy(outval + len, tmp, blocklen);
856 memset(tmp, 0, drbg_blocklen(drbg));
860 /* update function for Hash DRBG as defined in 10.1.1.2 / 10.1.1.3 */
861 static int drbg_hash_update(struct drbg_state *drbg, struct list_head *seed,
865 struct drbg_string data1, data2;
867 LIST_HEAD(datalist2);
868 unsigned char *V = drbg->scratchpad;
869 unsigned char prefix = DRBG_PREFIX1;
875 /* 10.1.1.3 step 1 */
876 memcpy(V, drbg->V, drbg_statelen(drbg));
877 drbg_string_fill(&data1, &prefix, 1);
878 list_add_tail(&data1.list, &datalist);
879 drbg_string_fill(&data2, V, drbg_statelen(drbg));
880 list_add_tail(&data2.list, &datalist);
882 list_splice_tail(seed, &datalist);
884 /* 10.1.1.2 / 10.1.1.3 step 2 and 3 */
885 ret = drbg_hash_df(drbg, drbg->V, drbg_statelen(drbg), &datalist);
889 /* 10.1.1.2 / 10.1.1.3 step 4 */
890 prefix = DRBG_PREFIX0;
891 drbg_string_fill(&data1, &prefix, 1);
892 list_add_tail(&data1.list, &datalist2);
893 drbg_string_fill(&data2, drbg->V, drbg_statelen(drbg));
894 list_add_tail(&data2.list, &datalist2);
895 /* 10.1.1.2 / 10.1.1.3 step 4 */
896 ret = drbg_hash_df(drbg, drbg->C, drbg_statelen(drbg), &datalist2);
899 memset(drbg->scratchpad, 0, drbg_statelen(drbg));
903 /* processing of additional information string for Hash DRBG */
904 static int drbg_hash_process_addtl(struct drbg_state *drbg,
905 struct list_head *addtl)
908 struct drbg_string data1, data2;
910 unsigned char prefix = DRBG_PREFIX2;
912 /* 10.1.1.4 step 2 */
913 if (!addtl || list_empty(addtl))
916 /* 10.1.1.4 step 2a */
917 drbg_string_fill(&data1, &prefix, 1);
918 drbg_string_fill(&data2, drbg->V, drbg_statelen(drbg));
919 list_add_tail(&data1.list, &datalist);
920 list_add_tail(&data2.list, &datalist);
921 list_splice_tail(addtl, &datalist);
922 ret = drbg_kcapi_hash(drbg, drbg->scratchpad, &datalist);
926 /* 10.1.1.4 step 2b */
927 drbg_add_buf(drbg->V, drbg_statelen(drbg),
928 drbg->scratchpad, drbg_blocklen(drbg));
931 memset(drbg->scratchpad, 0, drbg_blocklen(drbg));
935 /* Hashgen defined in 10.1.1.4 */
936 static int drbg_hash_hashgen(struct drbg_state *drbg,
942 unsigned char *src = drbg->scratchpad;
943 unsigned char *dst = drbg->scratchpad + drbg_statelen(drbg);
944 struct drbg_string data;
947 /* 10.1.1.4 step hashgen 2 */
948 memcpy(src, drbg->V, drbg_statelen(drbg));
950 drbg_string_fill(&data, src, drbg_statelen(drbg));
951 list_add_tail(&data.list, &datalist);
952 while (len < buflen) {
953 unsigned int outlen = 0;
954 /* 10.1.1.4 step hashgen 4.1 */
955 ret = drbg_kcapi_hash(drbg, dst, &datalist);
960 outlen = (drbg_blocklen(drbg) < (buflen - len)) ?
961 drbg_blocklen(drbg) : (buflen - len);
962 /* 10.1.1.4 step hashgen 4.2 */
963 memcpy(buf + len, dst, outlen);
965 /* 10.1.1.4 hashgen step 4.3 */
967 crypto_inc(src, drbg_statelen(drbg));
971 memset(drbg->scratchpad, 0,
972 (drbg_statelen(drbg) + drbg_blocklen(drbg)));
976 /* generate function for Hash DRBG as defined in 10.1.1.4 */
977 static int drbg_hash_generate(struct drbg_state *drbg,
978 unsigned char *buf, unsigned int buflen,
979 struct list_head *addtl)
984 unsigned char req[8];
987 unsigned char prefix = DRBG_PREFIX3;
988 struct drbg_string data1, data2;
991 /* 10.1.1.4 step 2 */
992 ret = drbg_hash_process_addtl(drbg, addtl);
995 /* 10.1.1.4 step 3 */
996 len = drbg_hash_hashgen(drbg, buf, buflen);
998 /* this is the value H as documented in 10.1.1.4 */
999 /* 10.1.1.4 step 4 */
1000 drbg_string_fill(&data1, &prefix, 1);
1001 list_add_tail(&data1.list, &datalist);
1002 drbg_string_fill(&data2, drbg->V, drbg_statelen(drbg));
1003 list_add_tail(&data2.list, &datalist);
1004 ret = drbg_kcapi_hash(drbg, drbg->scratchpad, &datalist);
1010 /* 10.1.1.4 step 5 */
1011 drbg_add_buf(drbg->V, drbg_statelen(drbg),
1012 drbg->scratchpad, drbg_blocklen(drbg));
1013 drbg_add_buf(drbg->V, drbg_statelen(drbg),
1014 drbg->C, drbg_statelen(drbg));
1015 u.req_int = cpu_to_be64(drbg->reseed_ctr);
1016 drbg_add_buf(drbg->V, drbg_statelen(drbg), u.req, 8);
1019 memset(drbg->scratchpad, 0, drbg_blocklen(drbg));
1024 * scratchpad usage: as update and generate are used isolated, both
1025 * can use the scratchpad
1027 static const struct drbg_state_ops drbg_hash_ops = {
1028 .update = drbg_hash_update,
1029 .generate = drbg_hash_generate,
1030 .crypto_init = drbg_init_hash_kernel,
1031 .crypto_fini = drbg_fini_hash_kernel,
1033 #endif /* CONFIG_CRYPTO_DRBG_HASH */
1035 /******************************************************************
1036 * Functions common for DRBG implementations
1037 ******************************************************************/
1039 static inline int __drbg_seed(struct drbg_state *drbg, struct list_head *seed,
1040 int reseed, enum drbg_seed_state new_seed_state)
1042 int ret = drbg->d_ops->update(drbg, seed, reseed);
1047 drbg->seeded = new_seed_state;
1048 /* 10.1.1.2 / 10.1.1.3 step 5 */
1049 drbg->reseed_ctr = 1;
1051 switch (drbg->seeded) {
1052 case DRBG_SEED_STATE_UNSEEDED:
1053 /* Impossible, but handle it to silence compiler warnings. */
1054 case DRBG_SEED_STATE_PARTIAL:
1056 * Require frequent reseeds until the seed source is
1057 * fully initialized.
1059 drbg->reseed_threshold = 50;
1062 case DRBG_SEED_STATE_FULL:
1064 * Seed source has become fully initialized, frequent
1065 * reseeds no longer required.
1067 drbg->reseed_threshold = drbg_max_requests(drbg);
1074 static inline int drbg_get_random_bytes(struct drbg_state *drbg,
1075 unsigned char *entropy,
1076 unsigned int entropylen)
1081 get_random_bytes(entropy, entropylen);
1082 ret = drbg_fips_continuous_test(drbg, entropy);
1083 if (ret && ret != -EAGAIN)
1090 static int drbg_seed_from_random(struct drbg_state *drbg)
1092 struct drbg_string data;
1093 LIST_HEAD(seedlist);
1094 unsigned int entropylen = drbg_sec_strength(drbg->core->flags);
1095 unsigned char entropy[32];
1098 BUG_ON(!entropylen);
1099 BUG_ON(entropylen > sizeof(entropy));
1101 drbg_string_fill(&data, entropy, entropylen);
1102 list_add_tail(&data.list, &seedlist);
1104 ret = drbg_get_random_bytes(drbg, entropy, entropylen);
1108 ret = __drbg_seed(drbg, &seedlist, true, DRBG_SEED_STATE_FULL);
1111 memzero_explicit(entropy, entropylen);
1116 * Seeding or reseeding of the DRBG
1118 * @drbg: DRBG state struct
1119 * @pers: personalization / additional information buffer
1120 * @reseed: 0 for initial seed process, 1 for reseeding
1124 * error value otherwise
1126 static int drbg_seed(struct drbg_state *drbg, struct drbg_string *pers,
1130 unsigned char entropy[((32 + 16) * 2)];
1131 unsigned int entropylen = drbg_sec_strength(drbg->core->flags);
1132 struct drbg_string data1;
1133 LIST_HEAD(seedlist);
1134 enum drbg_seed_state new_seed_state = DRBG_SEED_STATE_FULL;
1136 /* 9.1 / 9.2 / 9.3.1 step 3 */
1137 if (pers && pers->len > (drbg_max_addtl(drbg))) {
1138 pr_devel("DRBG: personalization string too long %zu\n",
1143 if (list_empty(&drbg->test_data.list)) {
1144 drbg_string_fill(&data1, drbg->test_data.buf,
1145 drbg->test_data.len);
1146 pr_devel("DRBG: using test entropy\n");
1149 * Gather entropy equal to the security strength of the DRBG.
1150 * With a derivation function, a nonce is required in addition
1151 * to the entropy. A nonce must be at least 1/2 of the security
1152 * strength of the DRBG in size. Thus, entropy + nonce is 3/2
1153 * of the strength. The consideration of a nonce is only
1154 * applicable during initial seeding.
1156 BUG_ON(!entropylen);
1158 entropylen = ((entropylen + 1) / 2) * 3;
1159 BUG_ON((entropylen * 2) > sizeof(entropy));
1161 /* Get seed from in-kernel /dev/urandom */
1162 if (!rng_is_initialized())
1163 new_seed_state = DRBG_SEED_STATE_PARTIAL;
1165 ret = drbg_get_random_bytes(drbg, entropy, entropylen);
1170 drbg_string_fill(&data1, entropy, entropylen);
1171 pr_devel("DRBG: (re)seeding with %u bytes of entropy\n",
1174 /* Get seed from Jitter RNG */
1175 ret = crypto_rng_get_bytes(drbg->jent,
1176 entropy + entropylen,
1179 pr_devel("DRBG: jent failed with %d\n", ret);
1182 * Do not treat the transient failure of the
1183 * Jitter RNG as an error that needs to be
1184 * reported. The combined number of the
1185 * maximum reseed threshold times the maximum
1186 * number of Jitter RNG transient errors is
1187 * less than the reseed threshold required by
1188 * SP800-90A allowing us to treat the
1189 * transient errors as such.
1191 * However, we mandate that at least the first
1192 * seeding operation must succeed with the
1195 if (!reseed || ret != -EAGAIN)
1199 drbg_string_fill(&data1, entropy, entropylen * 2);
1200 pr_devel("DRBG: (re)seeding with %u bytes of entropy\n",
1204 list_add_tail(&data1.list, &seedlist);
1207 * concatenation of entropy with personalization str / addtl input)
1208 * the variable pers is directly handed in by the caller, so check its
1209 * contents whether it is appropriate
1211 if (pers && pers->buf && 0 < pers->len) {
1212 list_add_tail(&pers->list, &seedlist);
1213 pr_devel("DRBG: using personalization string\n");
1217 memset(drbg->V, 0, drbg_statelen(drbg));
1218 memset(drbg->C, 0, drbg_statelen(drbg));
1221 ret = __drbg_seed(drbg, &seedlist, reseed, new_seed_state);
1224 memzero_explicit(entropy, entropylen * 2);
1229 /* Free all substructures in a DRBG state without the DRBG state structure */
1230 static inline void drbg_dealloc_state(struct drbg_state *drbg)
1240 kzfree(drbg->scratchpadbuf);
1241 drbg->scratchpadbuf = NULL;
1242 drbg->reseed_ctr = 0;
1245 if (IS_ENABLED(CONFIG_CRYPTO_FIPS)) {
1248 drbg->fips_primed = false;
1253 * Allocate all sub-structures for a DRBG state.
1254 * The DRBG state structure must already be allocated.
1256 static inline int drbg_alloc_state(struct drbg_state *drbg)
1259 unsigned int sb_size = 0;
1261 switch (drbg->core->flags & DRBG_TYPE_MASK) {
1262 #ifdef CONFIG_CRYPTO_DRBG_HMAC
1264 drbg->d_ops = &drbg_hmac_ops;
1266 #endif /* CONFIG_CRYPTO_DRBG_HMAC */
1267 #ifdef CONFIG_CRYPTO_DRBG_HASH
1269 drbg->d_ops = &drbg_hash_ops;
1271 #endif /* CONFIG_CRYPTO_DRBG_HASH */
1272 #ifdef CONFIG_CRYPTO_DRBG_CTR
1274 drbg->d_ops = &drbg_ctr_ops;
1276 #endif /* CONFIG_CRYPTO_DRBG_CTR */
1282 ret = drbg->d_ops->crypto_init(drbg);
1286 drbg->Vbuf = kmalloc(drbg_statelen(drbg) + ret, GFP_KERNEL);
1291 drbg->V = PTR_ALIGN(drbg->Vbuf, ret + 1);
1292 drbg->Cbuf = kmalloc(drbg_statelen(drbg) + ret, GFP_KERNEL);
1297 drbg->C = PTR_ALIGN(drbg->Cbuf, ret + 1);
1298 /* scratchpad is only generated for CTR and Hash */
1299 if (drbg->core->flags & DRBG_HMAC)
1301 else if (drbg->core->flags & DRBG_CTR)
1302 sb_size = drbg_statelen(drbg) + drbg_blocklen(drbg) + /* temp */
1303 drbg_statelen(drbg) + /* df_data */
1304 drbg_blocklen(drbg) + /* pad */
1305 drbg_blocklen(drbg) + /* iv */
1306 drbg_statelen(drbg) + drbg_blocklen(drbg); /* temp */
1308 sb_size = drbg_statelen(drbg) + drbg_blocklen(drbg);
1311 drbg->scratchpadbuf = kzalloc(sb_size + ret, GFP_KERNEL);
1312 if (!drbg->scratchpadbuf) {
1316 drbg->scratchpad = PTR_ALIGN(drbg->scratchpadbuf, ret + 1);
1319 if (IS_ENABLED(CONFIG_CRYPTO_FIPS)) {
1320 drbg->prev = kzalloc(drbg_sec_strength(drbg->core->flags),
1324 drbg->fips_primed = false;
1330 drbg->d_ops->crypto_fini(drbg);
1332 drbg_dealloc_state(drbg);
1336 /*************************************************************************
1337 * DRBG interface functions
1338 *************************************************************************/
1341 * DRBG generate function as required by SP800-90A - this function
1342 * generates random numbers
1344 * @drbg DRBG state handle
1345 * @buf Buffer where to store the random numbers -- the buffer must already
1346 * be pre-allocated by caller
1347 * @buflen Length of output buffer - this value defines the number of random
1348 * bytes pulled from DRBG
1349 * @addtl Additional input that is mixed into state, may be NULL -- note
1350 * the entropy is pulled by the DRBG internally unconditionally
1351 * as defined in SP800-90A. The additional input is mixed into
1352 * the state in addition to the pulled entropy.
1354 * return: 0 when all bytes are generated; < 0 in case of an error
1356 static int drbg_generate(struct drbg_state *drbg,
1357 unsigned char *buf, unsigned int buflen,
1358 struct drbg_string *addtl)
1361 LIST_HEAD(addtllist);
1364 pr_devel("DRBG: not yet seeded\n");
1367 if (0 == buflen || !buf) {
1368 pr_devel("DRBG: no output buffer provided\n");
1371 if (addtl && NULL == addtl->buf && 0 < addtl->len) {
1372 pr_devel("DRBG: wrong format of additional information\n");
1378 if (buflen > (drbg_max_request_bytes(drbg))) {
1379 pr_devel("DRBG: requested random numbers too large %u\n",
1384 /* 9.3.1 step 3 is implicit with the chosen DRBG */
1387 if (addtl && addtl->len > (drbg_max_addtl(drbg))) {
1388 pr_devel("DRBG: additional information string too long %zu\n",
1392 /* 9.3.1 step 5 is implicit with the chosen DRBG */
1395 * 9.3.1 step 6 and 9 supplemented by 9.3.2 step c is implemented
1396 * here. The spec is a bit convoluted here, we make it simpler.
1398 if (drbg->reseed_threshold < drbg->reseed_ctr)
1399 drbg->seeded = DRBG_SEED_STATE_UNSEEDED;
1401 if (drbg->pr || drbg->seeded == DRBG_SEED_STATE_UNSEEDED) {
1402 pr_devel("DRBG: reseeding before generation (prediction "
1403 "resistance: %s, state %s)\n",
1404 drbg->pr ? "true" : "false",
1405 (drbg->seeded == DRBG_SEED_STATE_FULL ?
1406 "seeded" : "unseeded"));
1407 /* 9.3.1 steps 7.1 through 7.3 */
1408 len = drbg_seed(drbg, addtl, true);
1411 /* 9.3.1 step 7.4 */
1413 } else if (rng_is_initialized() &&
1414 drbg->seeded == DRBG_SEED_STATE_PARTIAL) {
1415 len = drbg_seed_from_random(drbg);
1420 if (addtl && 0 < addtl->len)
1421 list_add_tail(&addtl->list, &addtllist);
1422 /* 9.3.1 step 8 and 10 */
1423 len = drbg->d_ops->generate(drbg, buf, buflen, &addtllist);
1425 /* 10.1.1.4 step 6, 10.1.2.5 step 7, 10.2.1.5.2 step 7 */
1431 * Section 11.3.3 requires to re-perform self tests after some
1432 * generated random numbers. The chosen value after which self
1433 * test is performed is arbitrary, but it should be reasonable.
1434 * However, we do not perform the self tests because of the following
1435 * reasons: it is mathematically impossible that the initial self tests
1436 * were successfully and the following are not. If the initial would
1437 * pass and the following would not, the kernel integrity is violated.
1438 * In this case, the entire kernel operation is questionable and it
1439 * is unlikely that the integrity violation only affects the
1440 * correct operation of the DRBG.
1442 * Albeit the following code is commented out, it is provided in
1443 * case somebody has a need to implement the test of 11.3.3.
1446 if (drbg->reseed_ctr && !(drbg->reseed_ctr % 4096)) {
1448 pr_devel("DRBG: start to perform self test\n");
1449 if (drbg->core->flags & DRBG_HMAC)
1450 err = alg_test("drbg_pr_hmac_sha256",
1451 "drbg_pr_hmac_sha256", 0, 0);
1452 else if (drbg->core->flags & DRBG_CTR)
1453 err = alg_test("drbg_pr_ctr_aes128",
1454 "drbg_pr_ctr_aes128", 0, 0);
1456 err = alg_test("drbg_pr_sha256",
1457 "drbg_pr_sha256", 0, 0);
1459 pr_err("DRBG: periodical self test failed\n");
1461 * uninstantiate implies that from now on, only errors
1462 * are returned when reusing this DRBG cipher handle
1464 drbg_uninstantiate(drbg);
1467 pr_devel("DRBG: self test successful\n");
1473 * All operations were successful, return 0 as mandated by
1474 * the kernel crypto API interface.
1482 * Wrapper around drbg_generate which can pull arbitrary long strings
1483 * from the DRBG without hitting the maximum request limitation.
1485 * Parameters: see drbg_generate
1486 * Return codes: see drbg_generate -- if one drbg_generate request fails,
1487 * the entire drbg_generate_long request fails
1489 static int drbg_generate_long(struct drbg_state *drbg,
1490 unsigned char *buf, unsigned int buflen,
1491 struct drbg_string *addtl)
1493 unsigned int len = 0;
1494 unsigned int slice = 0;
1497 unsigned int chunk = 0;
1498 slice = ((buflen - len) / drbg_max_request_bytes(drbg));
1499 chunk = slice ? drbg_max_request_bytes(drbg) : (buflen - len);
1500 mutex_lock(&drbg->drbg_mutex);
1501 err = drbg_generate(drbg, buf + len, chunk, addtl);
1502 mutex_unlock(&drbg->drbg_mutex);
1506 } while (slice > 0 && (len < buflen));
1510 static int drbg_prepare_hrng(struct drbg_state *drbg)
1512 /* We do not need an HRNG in test mode. */
1513 if (list_empty(&drbg->test_data.list))
1516 drbg->jent = crypto_alloc_rng("jitterentropy_rng", 0, 0);
1522 * DRBG instantiation function as required by SP800-90A - this function
1523 * sets up the DRBG handle, performs the initial seeding and all sanity
1524 * checks required by SP800-90A
1526 * @drbg memory of state -- if NULL, new memory is allocated
1527 * @pers Personalization string that is mixed into state, may be NULL -- note
1528 * the entropy is pulled by the DRBG internally unconditionally
1529 * as defined in SP800-90A. The additional input is mixed into
1530 * the state in addition to the pulled entropy.
1531 * @coreref reference to core
1532 * @pr prediction resistance enabled
1536 * error value otherwise
1538 static int drbg_instantiate(struct drbg_state *drbg, struct drbg_string *pers,
1539 int coreref, bool pr)
1544 pr_devel("DRBG: Initializing DRBG core %d with prediction resistance "
1545 "%s\n", coreref, pr ? "enabled" : "disabled");
1546 mutex_lock(&drbg->drbg_mutex);
1548 /* 9.1 step 1 is implicit with the selected DRBG type */
1551 * 9.1 step 2 is implicit as caller can select prediction resistance
1552 * and the flag is copied into drbg->flags --
1553 * all DRBG types support prediction resistance
1556 /* 9.1 step 4 is implicit in drbg_sec_strength */
1559 drbg->core = &drbg_cores[coreref];
1561 drbg->seeded = DRBG_SEED_STATE_UNSEEDED;
1562 drbg->reseed_threshold = drbg_max_requests(drbg);
1564 ret = drbg_alloc_state(drbg);
1568 ret = drbg_prepare_hrng(drbg);
1570 goto free_everything;
1572 if (IS_ERR(drbg->jent)) {
1573 ret = PTR_ERR(drbg->jent);
1575 if (fips_enabled || ret != -ENOENT)
1576 goto free_everything;
1577 pr_info("DRBG: Continuing without Jitter RNG\n");
1583 ret = drbg_seed(drbg, pers, reseed);
1586 goto free_everything;
1588 mutex_unlock(&drbg->drbg_mutex);
1592 mutex_unlock(&drbg->drbg_mutex);
1596 mutex_unlock(&drbg->drbg_mutex);
1597 drbg_uninstantiate(drbg);
1602 * DRBG uninstantiate function as required by SP800-90A - this function
1603 * frees all buffers and the DRBG handle
1605 * @drbg DRBG state handle
1610 static int drbg_uninstantiate(struct drbg_state *drbg)
1612 if (!IS_ERR_OR_NULL(drbg->jent))
1613 crypto_free_rng(drbg->jent);
1617 drbg->d_ops->crypto_fini(drbg);
1618 drbg_dealloc_state(drbg);
1619 /* no scrubbing of test_data -- this shall survive an uninstantiate */
1624 * Helper function for setting the test data in the DRBG
1626 * @drbg DRBG state handle
1628 * @len test data length
1630 static void drbg_kcapi_set_entropy(struct crypto_rng *tfm,
1631 const u8 *data, unsigned int len)
1633 struct drbg_state *drbg = crypto_rng_ctx(tfm);
1635 mutex_lock(&drbg->drbg_mutex);
1636 drbg_string_fill(&drbg->test_data, data, len);
1637 mutex_unlock(&drbg->drbg_mutex);
1640 /***************************************************************
1641 * Kernel crypto API cipher invocations requested by DRBG
1642 ***************************************************************/
1644 #if defined(CONFIG_CRYPTO_DRBG_HASH) || defined(CONFIG_CRYPTO_DRBG_HMAC)
1646 struct shash_desc shash;
1650 static int drbg_init_hash_kernel(struct drbg_state *drbg)
1652 struct sdesc *sdesc;
1653 struct crypto_shash *tfm;
1655 tfm = crypto_alloc_shash(drbg->core->backend_cra_name, 0, 0);
1657 pr_info("DRBG: could not allocate digest TFM handle: %s\n",
1658 drbg->core->backend_cra_name);
1659 return PTR_ERR(tfm);
1661 BUG_ON(drbg_blocklen(drbg) != crypto_shash_digestsize(tfm));
1662 sdesc = kzalloc(sizeof(struct shash_desc) + crypto_shash_descsize(tfm),
1665 crypto_free_shash(tfm);
1669 sdesc->shash.tfm = tfm;
1670 sdesc->shash.flags = 0;
1671 drbg->priv_data = sdesc;
1673 return crypto_shash_alignmask(tfm);
1676 static int drbg_fini_hash_kernel(struct drbg_state *drbg)
1678 struct sdesc *sdesc = (struct sdesc *)drbg->priv_data;
1680 crypto_free_shash(sdesc->shash.tfm);
1683 drbg->priv_data = NULL;
1687 static void drbg_kcapi_hmacsetkey(struct drbg_state *drbg,
1688 const unsigned char *key)
1690 struct sdesc *sdesc = (struct sdesc *)drbg->priv_data;
1692 crypto_shash_setkey(sdesc->shash.tfm, key, drbg_statelen(drbg));
1695 static int drbg_kcapi_hash(struct drbg_state *drbg, unsigned char *outval,
1696 const struct list_head *in)
1698 struct sdesc *sdesc = (struct sdesc *)drbg->priv_data;
1699 struct drbg_string *input = NULL;
1701 crypto_shash_init(&sdesc->shash);
1702 list_for_each_entry(input, in, list)
1703 crypto_shash_update(&sdesc->shash, input->buf, input->len);
1704 return crypto_shash_final(&sdesc->shash, outval);
1706 #endif /* (CONFIG_CRYPTO_DRBG_HASH || CONFIG_CRYPTO_DRBG_HMAC) */
1708 #ifdef CONFIG_CRYPTO_DRBG_CTR
1709 static int drbg_fini_sym_kernel(struct drbg_state *drbg)
1711 struct crypto_cipher *tfm =
1712 (struct crypto_cipher *)drbg->priv_data;
1714 crypto_free_cipher(tfm);
1715 drbg->priv_data = NULL;
1717 if (drbg->ctr_handle)
1718 crypto_free_skcipher(drbg->ctr_handle);
1719 drbg->ctr_handle = NULL;
1722 skcipher_request_free(drbg->ctr_req);
1723 drbg->ctr_req = NULL;
1725 kfree(drbg->ctr_null_value_buf);
1726 drbg->ctr_null_value = NULL;
1728 kfree(drbg->outscratchpadbuf);
1729 drbg->outscratchpadbuf = NULL;
1734 static void drbg_skcipher_cb(struct crypto_async_request *req, int error)
1736 struct drbg_state *drbg = req->data;
1738 if (error == -EINPROGRESS)
1740 drbg->ctr_async_err = error;
1741 complete(&drbg->ctr_completion);
1744 static int drbg_init_sym_kernel(struct drbg_state *drbg)
1746 struct crypto_cipher *tfm;
1747 struct crypto_skcipher *sk_tfm;
1748 struct skcipher_request *req;
1749 unsigned int alignmask;
1750 char ctr_name[CRYPTO_MAX_ALG_NAME];
1752 tfm = crypto_alloc_cipher(drbg->core->backend_cra_name, 0, 0);
1754 pr_info("DRBG: could not allocate cipher TFM handle: %s\n",
1755 drbg->core->backend_cra_name);
1756 return PTR_ERR(tfm);
1758 BUG_ON(drbg_blocklen(drbg) != crypto_cipher_blocksize(tfm));
1759 drbg->priv_data = tfm;
1761 if (snprintf(ctr_name, CRYPTO_MAX_ALG_NAME, "ctr(%s)",
1762 drbg->core->backend_cra_name) >= CRYPTO_MAX_ALG_NAME) {
1763 drbg_fini_sym_kernel(drbg);
1766 sk_tfm = crypto_alloc_skcipher(ctr_name, 0, 0);
1767 if (IS_ERR(sk_tfm)) {
1768 pr_info("DRBG: could not allocate CTR cipher TFM handle: %s\n",
1770 drbg_fini_sym_kernel(drbg);
1771 return PTR_ERR(sk_tfm);
1773 drbg->ctr_handle = sk_tfm;
1774 init_completion(&drbg->ctr_completion);
1776 req = skcipher_request_alloc(sk_tfm, GFP_KERNEL);
1778 pr_info("DRBG: could not allocate request queue\n");
1779 drbg_fini_sym_kernel(drbg);
1782 drbg->ctr_req = req;
1783 skcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG,
1784 drbg_skcipher_cb, drbg);
1786 alignmask = crypto_skcipher_alignmask(sk_tfm);
1787 drbg->ctr_null_value_buf = kzalloc(DRBG_CTR_NULL_LEN + alignmask,
1789 if (!drbg->ctr_null_value_buf) {
1790 drbg_fini_sym_kernel(drbg);
1793 drbg->ctr_null_value = (u8 *)PTR_ALIGN(drbg->ctr_null_value_buf,
1796 drbg->outscratchpadbuf = kmalloc(DRBG_OUTSCRATCHLEN + alignmask,
1798 if (!drbg->outscratchpadbuf) {
1799 drbg_fini_sym_kernel(drbg);
1802 drbg->outscratchpad = (u8 *)PTR_ALIGN(drbg->outscratchpadbuf,
1808 static void drbg_kcapi_symsetkey(struct drbg_state *drbg,
1809 const unsigned char *key)
1811 struct crypto_cipher *tfm =
1812 (struct crypto_cipher *)drbg->priv_data;
1814 crypto_cipher_setkey(tfm, key, (drbg_keylen(drbg)));
1817 static int drbg_kcapi_sym(struct drbg_state *drbg, unsigned char *outval,
1818 const struct drbg_string *in)
1820 struct crypto_cipher *tfm =
1821 (struct crypto_cipher *)drbg->priv_data;
1823 /* there is only component in *in */
1824 BUG_ON(in->len < drbg_blocklen(drbg));
1825 crypto_cipher_encrypt_one(tfm, outval, in->buf);
1829 static int drbg_kcapi_sym_ctr(struct drbg_state *drbg,
1830 u8 *inbuf, u32 inlen,
1831 u8 *outbuf, u32 outlen)
1833 struct scatterlist sg_in, sg_out;
1836 sg_init_one(&sg_in, inbuf, inlen);
1837 sg_init_one(&sg_out, drbg->outscratchpad, DRBG_OUTSCRATCHLEN);
1840 u32 cryptlen = min3(inlen, outlen, (u32)DRBG_OUTSCRATCHLEN);
1842 /* Output buffer may not be valid for SGL, use scratchpad */
1843 skcipher_request_set_crypt(drbg->ctr_req, &sg_in, &sg_out,
1845 ret = crypto_skcipher_encrypt(drbg->ctr_req);
1851 wait_for_completion(&drbg->ctr_completion);
1852 if (!drbg->ctr_async_err) {
1853 reinit_completion(&drbg->ctr_completion);
1859 init_completion(&drbg->ctr_completion);
1861 memcpy(outbuf, drbg->outscratchpad, cryptlen);
1869 memzero_explicit(drbg->outscratchpad, DRBG_OUTSCRATCHLEN);
1872 #endif /* CONFIG_CRYPTO_DRBG_CTR */
1874 /***************************************************************
1875 * Kernel crypto API interface to register DRBG
1876 ***************************************************************/
1879 * Look up the DRBG flags by given kernel crypto API cra_name
1880 * The code uses the drbg_cores definition to do this
1882 * @cra_name kernel crypto API cra_name
1883 * @coreref reference to integer which is filled with the pointer to
1884 * the applicable core
1885 * @pr reference for setting prediction resistance
1889 static inline void drbg_convert_tfm_core(const char *cra_driver_name,
1890 int *coreref, bool *pr)
1897 /* disassemble the names */
1898 if (!memcmp(cra_driver_name, "drbg_nopr_", 10)) {
1901 } else if (!memcmp(cra_driver_name, "drbg_pr_", 8)) {
1907 /* remove the first part */
1908 len = strlen(cra_driver_name) - start;
1909 for (i = 0; ARRAY_SIZE(drbg_cores) > i; i++) {
1910 if (!memcmp(cra_driver_name + start, drbg_cores[i].cra_name,
1918 static int drbg_kcapi_init(struct crypto_tfm *tfm)
1920 struct drbg_state *drbg = crypto_tfm_ctx(tfm);
1922 mutex_init(&drbg->drbg_mutex);
1927 static void drbg_kcapi_cleanup(struct crypto_tfm *tfm)
1929 drbg_uninstantiate(crypto_tfm_ctx(tfm));
1933 * Generate random numbers invoked by the kernel crypto API:
1934 * The API of the kernel crypto API is extended as follows:
1936 * src is additional input supplied to the RNG.
1937 * slen is the length of src.
1938 * dst is the output buffer where random data is to be stored.
1939 * dlen is the length of dst.
1941 static int drbg_kcapi_random(struct crypto_rng *tfm,
1942 const u8 *src, unsigned int slen,
1943 u8 *dst, unsigned int dlen)
1945 struct drbg_state *drbg = crypto_rng_ctx(tfm);
1946 struct drbg_string *addtl = NULL;
1947 struct drbg_string string;
1950 /* linked list variable is now local to allow modification */
1951 drbg_string_fill(&string, src, slen);
1955 return drbg_generate_long(drbg, dst, dlen, addtl);
1959 * Seed the DRBG invoked by the kernel crypto API
1961 static int drbg_kcapi_seed(struct crypto_rng *tfm,
1962 const u8 *seed, unsigned int slen)
1964 struct drbg_state *drbg = crypto_rng_ctx(tfm);
1965 struct crypto_tfm *tfm_base = crypto_rng_tfm(tfm);
1967 struct drbg_string string;
1968 struct drbg_string *seed_string = NULL;
1971 drbg_convert_tfm_core(crypto_tfm_alg_driver_name(tfm_base), &coreref,
1974 drbg_string_fill(&string, seed, slen);
1975 seed_string = &string;
1978 return drbg_instantiate(drbg, seed_string, coreref, pr);
1981 /***************************************************************
1982 * Kernel module: code to load the module
1983 ***************************************************************/
1986 * Tests as defined in 11.3.2 in addition to the cipher tests: testing
1987 * of the error handling.
1989 * Note: testing of failing seed source as defined in 11.3.2 is not applicable
1990 * as seed source of get_random_bytes does not fail.
1992 * Note 2: There is no sensible way of testing the reseed counter
1993 * enforcement, so skip it.
1995 static inline int __init drbg_healthcheck_sanity(void)
1998 #define OUTBUFLEN 16
1999 unsigned char buf[OUTBUFLEN];
2000 struct drbg_state *drbg = NULL;
2005 struct drbg_string addtl;
2006 size_t max_addtllen, max_request_bytes;
2008 /* only perform test in FIPS mode */
2012 #ifdef CONFIG_CRYPTO_DRBG_CTR
2013 drbg_convert_tfm_core("drbg_nopr_ctr_aes128", &coreref, &pr);
2014 #elif defined CONFIG_CRYPTO_DRBG_HASH
2015 drbg_convert_tfm_core("drbg_nopr_sha256", &coreref, &pr);
2017 drbg_convert_tfm_core("drbg_nopr_hmac_sha256", &coreref, &pr);
2020 drbg = kzalloc(sizeof(struct drbg_state), GFP_KERNEL);
2024 mutex_init(&drbg->drbg_mutex);
2025 drbg->core = &drbg_cores[coreref];
2026 drbg->reseed_threshold = drbg_max_requests(drbg);
2029 * if the following tests fail, it is likely that there is a buffer
2030 * overflow as buf is much smaller than the requested or provided
2031 * string lengths -- in case the error handling does not succeed
2032 * we may get an OOPS. And we want to get an OOPS as this is a
2036 max_addtllen = drbg_max_addtl(drbg);
2037 max_request_bytes = drbg_max_request_bytes(drbg);
2038 drbg_string_fill(&addtl, buf, max_addtllen + 1);
2039 /* overflow addtllen with additonal info string */
2040 len = drbg_generate(drbg, buf, OUTBUFLEN, &addtl);
2042 /* overflow max_bits */
2043 len = drbg_generate(drbg, buf, (max_request_bytes + 1), NULL);
2046 /* overflow max addtllen with personalization string */
2047 ret = drbg_seed(drbg, &addtl, false);
2049 /* all tests passed */
2052 pr_devel("DRBG: Sanity tests for failure code paths successfully "
2059 static struct rng_alg drbg_algs[22];
2062 * Fill the array drbg_algs used to register the different DRBGs
2063 * with the kernel crypto API. To fill the array, the information
2064 * from drbg_cores[] is used.
2066 static inline void __init drbg_fill_array(struct rng_alg *alg,
2067 const struct drbg_core *core, int pr)
2070 static int priority = 200;
2072 memcpy(alg->base.cra_name, "stdrng", 6);
2074 memcpy(alg->base.cra_driver_name, "drbg_pr_", 8);
2077 memcpy(alg->base.cra_driver_name, "drbg_nopr_", 10);
2080 memcpy(alg->base.cra_driver_name + pos, core->cra_name,
2081 strlen(core->cra_name));
2083 alg->base.cra_priority = priority;
2086 * If FIPS mode enabled, the selected DRBG shall have the
2087 * highest cra_priority over other stdrng instances to ensure
2091 alg->base.cra_priority += 200;
2093 alg->base.cra_ctxsize = sizeof(struct drbg_state);
2094 alg->base.cra_module = THIS_MODULE;
2095 alg->base.cra_init = drbg_kcapi_init;
2096 alg->base.cra_exit = drbg_kcapi_cleanup;
2097 alg->generate = drbg_kcapi_random;
2098 alg->seed = drbg_kcapi_seed;
2099 alg->set_ent = drbg_kcapi_set_entropy;
2103 static int __init drbg_init(void)
2105 unsigned int i = 0; /* pointer to drbg_algs */
2106 unsigned int j = 0; /* pointer to drbg_cores */
2109 ret = drbg_healthcheck_sanity();
2113 if (ARRAY_SIZE(drbg_cores) * 2 > ARRAY_SIZE(drbg_algs)) {
2114 pr_info("DRBG: Cannot register all DRBG types"
2115 "(slots needed: %zu, slots available: %zu)\n",
2116 ARRAY_SIZE(drbg_cores) * 2, ARRAY_SIZE(drbg_algs));
2121 * each DRBG definition can be used with PR and without PR, thus
2122 * we instantiate each DRBG in drbg_cores[] twice.
2124 * As the order of placing them into the drbg_algs array matters
2125 * (the later DRBGs receive a higher cra_priority) we register the
2126 * prediction resistance DRBGs first as the should not be too
2129 for (j = 0; ARRAY_SIZE(drbg_cores) > j; j++, i++)
2130 drbg_fill_array(&drbg_algs[i], &drbg_cores[j], 1);
2131 for (j = 0; ARRAY_SIZE(drbg_cores) > j; j++, i++)
2132 drbg_fill_array(&drbg_algs[i], &drbg_cores[j], 0);
2133 return crypto_register_rngs(drbg_algs, (ARRAY_SIZE(drbg_cores) * 2));
2136 static void __exit drbg_exit(void)
2138 crypto_unregister_rngs(drbg_algs, (ARRAY_SIZE(drbg_cores) * 2));
2141 module_init(drbg_init);
2142 module_exit(drbg_exit);
2143 #ifndef CRYPTO_DRBG_HASH_STRING
2144 #define CRYPTO_DRBG_HASH_STRING ""
2146 #ifndef CRYPTO_DRBG_HMAC_STRING
2147 #define CRYPTO_DRBG_HMAC_STRING ""
2149 #ifndef CRYPTO_DRBG_CTR_STRING
2150 #define CRYPTO_DRBG_CTR_STRING ""
2152 MODULE_LICENSE("GPL");
2153 MODULE_AUTHOR("Stephan Mueller <smueller@chronox.de>");
2154 MODULE_DESCRIPTION("NIST SP800-90A Deterministic Random Bit Generator (DRBG) "
2155 "using following cores: "
2156 CRYPTO_DRBG_HASH_STRING
2157 CRYPTO_DRBG_HMAC_STRING
2158 CRYPTO_DRBG_CTR_STRING);
2159 MODULE_ALIAS_CRYPTO("stdrng");