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
224 * The test is performed on the result of one round of the output
225 * function. Thus, the function implicitly knows the size of the
229 * @buf output buffer of random data to be checked
235 static bool drbg_fips_continuous_test(struct drbg_state *drbg,
236 const unsigned char *buf)
238 #ifdef CONFIG_CRYPTO_FIPS
240 /* skip test if we test the overall system */
241 if (list_empty(&drbg->test_data.list))
243 /* only perform test in FIPS mode */
244 if (0 == fips_enabled)
246 if (!drbg->fips_primed) {
247 /* Priming of FIPS test */
248 memcpy(drbg->prev, buf, drbg_blocklen(drbg));
249 drbg->fips_primed = true;
250 /* return false due to priming, i.e. another round is needed */
253 ret = memcmp(drbg->prev, buf, drbg_blocklen(drbg));
255 panic("DRBG continuous self test failed\n");
256 memcpy(drbg->prev, buf, drbg_blocklen(drbg));
257 /* the test shall pass when the two compared values are not equal */
261 #endif /* CONFIG_CRYPTO_FIPS */
265 * Convert an integer into a byte representation of this integer.
266 * The byte representation is big-endian
268 * @val value to be converted
269 * @buf buffer holding the converted integer -- caller must ensure that
270 * buffer size is at least 32 bit
272 #if (defined(CONFIG_CRYPTO_DRBG_HASH) || defined(CONFIG_CRYPTO_DRBG_CTR))
273 static inline void drbg_cpu_to_be32(__u32 val, unsigned char *buf)
278 struct s *conversion = (struct s *) buf;
280 conversion->conv = cpu_to_be32(val);
282 #endif /* defined(CONFIG_CRYPTO_DRBG_HASH) || defined(CONFIG_CRYPTO_DRBG_CTR) */
284 /******************************************************************
285 * CTR DRBG callback functions
286 ******************************************************************/
288 #ifdef CONFIG_CRYPTO_DRBG_CTR
289 #define CRYPTO_DRBG_CTR_STRING "CTR "
290 MODULE_ALIAS_CRYPTO("drbg_pr_ctr_aes256");
291 MODULE_ALIAS_CRYPTO("drbg_nopr_ctr_aes256");
292 MODULE_ALIAS_CRYPTO("drbg_pr_ctr_aes192");
293 MODULE_ALIAS_CRYPTO("drbg_nopr_ctr_aes192");
294 MODULE_ALIAS_CRYPTO("drbg_pr_ctr_aes128");
295 MODULE_ALIAS_CRYPTO("drbg_nopr_ctr_aes128");
297 static int drbg_kcapi_sym(struct drbg_state *drbg, const unsigned char *key,
298 unsigned char *outval, const struct drbg_string *in);
299 static int drbg_init_sym_kernel(struct drbg_state *drbg);
300 static int drbg_fini_sym_kernel(struct drbg_state *drbg);
302 /* BCC function for CTR DRBG as defined in 10.4.3 */
303 static int drbg_ctr_bcc(struct drbg_state *drbg,
304 unsigned char *out, const unsigned char *key,
305 struct list_head *in)
308 struct drbg_string *curr = NULL;
309 struct drbg_string data;
312 drbg_string_fill(&data, out, drbg_blocklen(drbg));
314 /* 10.4.3 step 2 / 4 */
315 list_for_each_entry(curr, in, list) {
316 const unsigned char *pos = curr->buf;
317 size_t len = curr->len;
318 /* 10.4.3 step 4.1 */
320 /* 10.4.3 step 4.2 */
321 if (drbg_blocklen(drbg) == cnt) {
323 ret = drbg_kcapi_sym(drbg, key, out, &data);
333 /* 10.4.3 step 4.2 for last block */
335 ret = drbg_kcapi_sym(drbg, key, out, &data);
341 * scratchpad usage: drbg_ctr_update is interlinked with drbg_ctr_df
342 * (and drbg_ctr_bcc, but this function does not need any temporary buffers),
343 * the scratchpad is used as follows:
346 * start: drbg->scratchpad
347 * length: drbg_statelen(drbg) + drbg_blocklen(drbg)
348 * note: the cipher writing into this variable works
349 * blocklen-wise. Now, when the statelen is not a multiple
350 * of blocklen, the generateion loop below "spills over"
351 * by at most blocklen. Thus, we need to give sufficient
354 * start: drbg->scratchpad +
355 * drbg_statelen(drbg) + drbg_blocklen(drbg)
356 * length: drbg_statelen(drbg)
360 * start: df_data + drbg_statelen(drbg)
361 * length: drbg_blocklen(drbg)
363 * start: pad + drbg_blocklen(drbg)
364 * length: drbg_blocklen(drbg)
366 * start: iv + drbg_blocklen(drbg)
367 * length: drbg_satelen(drbg) + drbg_blocklen(drbg)
368 * note: temp is the buffer that the BCC function operates
369 * on. BCC operates blockwise. drbg_statelen(drbg)
370 * is sufficient when the DRBG state length is a multiple
371 * of the block size. For AES192 (and maybe other ciphers)
372 * this is not correct and the length for temp is
373 * insufficient (yes, that also means for such ciphers,
374 * the final output of all BCC rounds are truncated).
375 * Therefore, add drbg_blocklen(drbg) to cover all
379 /* Derivation Function for CTR DRBG as defined in 10.4.2 */
380 static int drbg_ctr_df(struct drbg_state *drbg,
381 unsigned char *df_data, size_t bytes_to_return,
382 struct list_head *seedlist)
385 unsigned char L_N[8];
387 struct drbg_string S1, S2, S4, cipherin;
389 unsigned char *pad = df_data + drbg_statelen(drbg);
390 unsigned char *iv = pad + drbg_blocklen(drbg);
391 unsigned char *temp = iv + drbg_blocklen(drbg);
393 unsigned int templen = 0;
397 const unsigned char *K = (unsigned char *)
398 "\x00\x01\x02\x03\x04\x05\x06\x07"
399 "\x08\x09\x0a\x0b\x0c\x0d\x0e\x0f"
400 "\x10\x11\x12\x13\x14\x15\x16\x17"
401 "\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f";
403 size_t generated_len = 0;
405 struct drbg_string *seed = NULL;
407 memset(pad, 0, drbg_blocklen(drbg));
408 memset(iv, 0, drbg_blocklen(drbg));
410 /* 10.4.2 step 1 is implicit as we work byte-wise */
413 if ((512/8) < bytes_to_return)
416 /* 10.4.2 step 2 -- calculate the entire length of all input data */
417 list_for_each_entry(seed, seedlist, list)
418 inputlen += seed->len;
419 drbg_cpu_to_be32(inputlen, &L_N[0]);
422 drbg_cpu_to_be32(bytes_to_return, &L_N[4]);
424 /* 10.4.2 step 5: length is L_N, input_string, one byte, padding */
425 padlen = (inputlen + sizeof(L_N) + 1) % (drbg_blocklen(drbg));
426 /* wrap the padlen appropriately */
428 padlen = drbg_blocklen(drbg) - padlen;
430 * pad / padlen contains the 0x80 byte and the following zero bytes.
431 * As the calculated padlen value only covers the number of zero
432 * bytes, this value has to be incremented by one for the 0x80 byte.
437 /* 10.4.2 step 4 -- first fill the linked list and then order it */
438 drbg_string_fill(&S1, iv, drbg_blocklen(drbg));
439 list_add_tail(&S1.list, &bcc_list);
440 drbg_string_fill(&S2, L_N, sizeof(L_N));
441 list_add_tail(&S2.list, &bcc_list);
442 list_splice_tail(seedlist, &bcc_list);
443 drbg_string_fill(&S4, pad, padlen);
444 list_add_tail(&S4.list, &bcc_list);
447 while (templen < (drbg_keylen(drbg) + (drbg_blocklen(drbg)))) {
449 * 10.4.2 step 9.1 - the padding is implicit as the buffer
450 * holds zeros after allocation -- even the increment of i
451 * is irrelevant as the increment remains within length of i
453 drbg_cpu_to_be32(i, iv);
454 /* 10.4.2 step 9.2 -- BCC and concatenation with temp */
455 ret = drbg_ctr_bcc(drbg, temp + templen, K, &bcc_list);
458 /* 10.4.2 step 9.3 */
460 templen += drbg_blocklen(drbg);
464 X = temp + (drbg_keylen(drbg));
465 drbg_string_fill(&cipherin, X, drbg_blocklen(drbg));
467 /* 10.4.2 step 12: overwriting of outval is implemented in next step */
470 while (generated_len < bytes_to_return) {
473 * 10.4.2 step 13.1: the truncation of the key length is
474 * implicit as the key is only drbg_blocklen in size based on
475 * the implementation of the cipher function callback
477 ret = drbg_kcapi_sym(drbg, temp, X, &cipherin);
480 blocklen = (drbg_blocklen(drbg) <
481 (bytes_to_return - generated_len)) ?
482 drbg_blocklen(drbg) :
483 (bytes_to_return - generated_len);
484 /* 10.4.2 step 13.2 and 14 */
485 memcpy(df_data + generated_len, X, blocklen);
486 generated_len += blocklen;
492 memset(iv, 0, drbg_blocklen(drbg));
493 memset(temp, 0, drbg_statelen(drbg) + drbg_blocklen(drbg));
494 memset(pad, 0, drbg_blocklen(drbg));
499 * update function of CTR DRBG as defined in 10.2.1.2
501 * The reseed variable has an enhanced meaning compared to the update
502 * functions of the other DRBGs as follows:
503 * 0 => initial seed from initialization
504 * 1 => reseed via drbg_seed
505 * 2 => first invocation from drbg_ctr_update when addtl is present. In
506 * this case, the df_data scratchpad is not deleted so that it is
507 * available for another calls to prevent calling the DF function
509 * 3 => second invocation from drbg_ctr_update. When the update function
510 * was called with addtl, the df_data memory already contains the
511 * DFed addtl information and we do not need to call DF again.
513 static int drbg_ctr_update(struct drbg_state *drbg, struct list_head *seed,
517 /* 10.2.1.2 step 1 */
518 unsigned char *temp = drbg->scratchpad;
519 unsigned char *df_data = drbg->scratchpad + drbg_statelen(drbg) +
521 unsigned char *temp_p, *df_data_p; /* pointer to iterate over buffers */
522 unsigned int len = 0;
523 struct drbg_string cipherin;
526 memset(df_data, 0, drbg_statelen(drbg));
528 /* 10.2.1.3.2 step 2 and 10.2.1.4.2 step 2 */
530 ret = drbg_ctr_df(drbg, df_data, drbg_statelen(drbg), seed);
535 drbg_string_fill(&cipherin, drbg->V, drbg_blocklen(drbg));
537 * 10.2.1.3.2 steps 2 and 3 are already covered as the allocation
538 * zeroizes all memory during initialization
540 while (len < (drbg_statelen(drbg))) {
541 /* 10.2.1.2 step 2.1 */
542 crypto_inc(drbg->V, drbg_blocklen(drbg));
544 * 10.2.1.2 step 2.2 */
545 ret = drbg_kcapi_sym(drbg, drbg->C, temp + len, &cipherin);
548 /* 10.2.1.2 step 2.3 and 3 */
549 len += drbg_blocklen(drbg);
552 /* 10.2.1.2 step 4 */
555 for (len = 0; len < drbg_statelen(drbg); len++) {
556 *temp_p ^= *df_data_p;
557 df_data_p++; temp_p++;
560 /* 10.2.1.2 step 5 */
561 memcpy(drbg->C, temp, drbg_keylen(drbg));
562 /* 10.2.1.2 step 6 */
563 memcpy(drbg->V, temp + drbg_keylen(drbg), drbg_blocklen(drbg));
567 memset(temp, 0, drbg_statelen(drbg) + drbg_blocklen(drbg));
569 memset(df_data, 0, drbg_statelen(drbg));
574 * scratchpad use: drbg_ctr_update is called independently from
575 * drbg_ctr_extract_bytes. Therefore, the scratchpad is reused
577 /* Generate function of CTR DRBG as defined in 10.2.1.5.2 */
578 static int drbg_ctr_generate(struct drbg_state *drbg,
579 unsigned char *buf, unsigned int buflen,
580 struct list_head *addtl)
584 struct drbg_string data;
586 /* 10.2.1.5.2 step 2 */
587 if (addtl && !list_empty(addtl)) {
588 ret = drbg_ctr_update(drbg, addtl, 2);
593 /* 10.2.1.5.2 step 4.1 */
594 crypto_inc(drbg->V, drbg_blocklen(drbg));
595 drbg_string_fill(&data, drbg->V, drbg_blocklen(drbg));
596 while (len < buflen) {
598 /* 10.2.1.5.2 step 4.2 */
599 ret = drbg_kcapi_sym(drbg, drbg->C, drbg->scratchpad, &data);
604 outlen = (drbg_blocklen(drbg) < (buflen - len)) ?
605 drbg_blocklen(drbg) : (buflen - len);
606 if (!drbg_fips_continuous_test(drbg, drbg->scratchpad)) {
607 /* 10.2.1.5.2 step 6 */
608 crypto_inc(drbg->V, drbg_blocklen(drbg));
611 /* 10.2.1.5.2 step 4.3 */
612 memcpy(buf + len, drbg->scratchpad, outlen);
614 /* 10.2.1.5.2 step 6 */
616 crypto_inc(drbg->V, drbg_blocklen(drbg));
619 /* 10.2.1.5.2 step 6 */
620 ret = drbg_ctr_update(drbg, NULL, 3);
625 memset(drbg->scratchpad, 0, drbg_blocklen(drbg));
629 static struct drbg_state_ops drbg_ctr_ops = {
630 .update = drbg_ctr_update,
631 .generate = drbg_ctr_generate,
632 .crypto_init = drbg_init_sym_kernel,
633 .crypto_fini = drbg_fini_sym_kernel,
635 #endif /* CONFIG_CRYPTO_DRBG_CTR */
637 /******************************************************************
638 * HMAC DRBG callback functions
639 ******************************************************************/
641 #if defined(CONFIG_CRYPTO_DRBG_HASH) || defined(CONFIG_CRYPTO_DRBG_HMAC)
642 static int drbg_kcapi_hash(struct drbg_state *drbg, const unsigned char *key,
643 unsigned char *outval, const struct list_head *in);
644 static int drbg_init_hash_kernel(struct drbg_state *drbg);
645 static int drbg_fini_hash_kernel(struct drbg_state *drbg);
646 #endif /* (CONFIG_CRYPTO_DRBG_HASH || CONFIG_CRYPTO_DRBG_HMAC) */
648 #ifdef CONFIG_CRYPTO_DRBG_HMAC
649 #define CRYPTO_DRBG_HMAC_STRING "HMAC "
650 MODULE_ALIAS_CRYPTO("drbg_pr_hmac_sha512");
651 MODULE_ALIAS_CRYPTO("drbg_nopr_hmac_sha512");
652 MODULE_ALIAS_CRYPTO("drbg_pr_hmac_sha384");
653 MODULE_ALIAS_CRYPTO("drbg_nopr_hmac_sha384");
654 MODULE_ALIAS_CRYPTO("drbg_pr_hmac_sha256");
655 MODULE_ALIAS_CRYPTO("drbg_nopr_hmac_sha256");
656 MODULE_ALIAS_CRYPTO("drbg_pr_hmac_sha1");
657 MODULE_ALIAS_CRYPTO("drbg_nopr_hmac_sha1");
659 /* update function of HMAC DRBG as defined in 10.1.2.2 */
660 static int drbg_hmac_update(struct drbg_state *drbg, struct list_head *seed,
665 struct drbg_string seed1, seed2, vdata;
667 LIST_HEAD(vdatalist);
670 /* 10.1.2.3 step 2 -- memset(0) of C is implicit with kzalloc */
671 memset(drbg->V, 1, drbg_statelen(drbg));
673 drbg_string_fill(&seed1, drbg->V, drbg_statelen(drbg));
674 list_add_tail(&seed1.list, &seedlist);
675 /* buffer of seed2 will be filled in for loop below with one byte */
676 drbg_string_fill(&seed2, NULL, 1);
677 list_add_tail(&seed2.list, &seedlist);
678 /* input data of seed is allowed to be NULL at this point */
680 list_splice_tail(seed, &seedlist);
682 drbg_string_fill(&vdata, drbg->V, drbg_statelen(drbg));
683 list_add_tail(&vdata.list, &vdatalist);
684 for (i = 2; 0 < i; i--) {
685 /* first round uses 0x0, second 0x1 */
686 unsigned char prefix = DRBG_PREFIX0;
688 prefix = DRBG_PREFIX1;
689 /* 10.1.2.2 step 1 and 4 -- concatenation and HMAC for key */
691 ret = drbg_kcapi_hash(drbg, drbg->C, drbg->C, &seedlist);
695 /* 10.1.2.2 step 2 and 5 -- HMAC for V */
696 ret = drbg_kcapi_hash(drbg, drbg->C, drbg->V, &vdatalist);
700 /* 10.1.2.2 step 3 */
708 /* generate function of HMAC DRBG as defined in 10.1.2.5 */
709 static int drbg_hmac_generate(struct drbg_state *drbg,
712 struct list_head *addtl)
716 struct drbg_string data;
719 /* 10.1.2.5 step 2 */
720 if (addtl && !list_empty(addtl)) {
721 ret = drbg_hmac_update(drbg, addtl, 1);
726 drbg_string_fill(&data, drbg->V, drbg_statelen(drbg));
727 list_add_tail(&data.list, &datalist);
728 while (len < buflen) {
729 unsigned int outlen = 0;
730 /* 10.1.2.5 step 4.1 */
731 ret = drbg_kcapi_hash(drbg, drbg->C, drbg->V, &datalist);
734 outlen = (drbg_blocklen(drbg) < (buflen - len)) ?
735 drbg_blocklen(drbg) : (buflen - len);
736 if (!drbg_fips_continuous_test(drbg, drbg->V))
739 /* 10.1.2.5 step 4.2 */
740 memcpy(buf + len, drbg->V, outlen);
744 /* 10.1.2.5 step 6 */
745 if (addtl && !list_empty(addtl))
746 ret = drbg_hmac_update(drbg, addtl, 1);
748 ret = drbg_hmac_update(drbg, NULL, 1);
755 static struct drbg_state_ops drbg_hmac_ops = {
756 .update = drbg_hmac_update,
757 .generate = drbg_hmac_generate,
758 .crypto_init = drbg_init_hash_kernel,
759 .crypto_fini = drbg_fini_hash_kernel,
761 #endif /* CONFIG_CRYPTO_DRBG_HMAC */
763 /******************************************************************
764 * Hash DRBG callback functions
765 ******************************************************************/
767 #ifdef CONFIG_CRYPTO_DRBG_HASH
768 #define CRYPTO_DRBG_HASH_STRING "HASH "
769 MODULE_ALIAS_CRYPTO("drbg_pr_sha512");
770 MODULE_ALIAS_CRYPTO("drbg_nopr_sha512");
771 MODULE_ALIAS_CRYPTO("drbg_pr_sha384");
772 MODULE_ALIAS_CRYPTO("drbg_nopr_sha384");
773 MODULE_ALIAS_CRYPTO("drbg_pr_sha256");
774 MODULE_ALIAS_CRYPTO("drbg_nopr_sha256");
775 MODULE_ALIAS_CRYPTO("drbg_pr_sha1");
776 MODULE_ALIAS_CRYPTO("drbg_nopr_sha1");
781 * @dst buffer to increment
784 static inline void drbg_add_buf(unsigned char *dst, size_t dstlen,
785 const unsigned char *add, size_t addlen)
787 /* implied: dstlen > addlen */
788 unsigned char *dstptr;
789 const unsigned char *addptr;
790 unsigned int remainder = 0;
793 dstptr = dst + (dstlen-1);
794 addptr = add + (addlen-1);
796 remainder += *dstptr + *addptr;
797 *dstptr = remainder & 0xff;
799 len--; dstptr--; addptr--;
801 len = dstlen - addlen;
802 while (len && remainder > 0) {
803 remainder = *dstptr + 1;
804 *dstptr = remainder & 0xff;
811 * scratchpad usage: as drbg_hash_update and drbg_hash_df are used
812 * interlinked, the scratchpad is used as follows:
814 * start: drbg->scratchpad
815 * length: drbg_statelen(drbg)
817 * start: drbg->scratchpad + drbg_statelen(drbg)
818 * length: drbg_blocklen(drbg)
820 * drbg_hash_process_addtl uses the scratchpad, but fully completes
821 * before either of the functions mentioned before are invoked. Therefore,
822 * drbg_hash_process_addtl does not need to be specifically considered.
825 /* Derivation Function for Hash DRBG as defined in 10.4.1 */
826 static int drbg_hash_df(struct drbg_state *drbg,
827 unsigned char *outval, size_t outlen,
828 struct list_head *entropylist)
832 unsigned char input[5];
833 unsigned char *tmp = drbg->scratchpad + drbg_statelen(drbg);
834 struct drbg_string data;
838 drbg_cpu_to_be32((outlen * 8), &input[1]);
840 /* 10.4.1 step 4.1 -- concatenation of data for input into hash */
841 drbg_string_fill(&data, input, 5);
842 list_add(&data.list, entropylist);
845 while (len < outlen) {
847 /* 10.4.1 step 4.1 */
848 ret = drbg_kcapi_hash(drbg, NULL, tmp, entropylist);
851 /* 10.4.1 step 4.2 */
853 blocklen = (drbg_blocklen(drbg) < (outlen - len)) ?
854 drbg_blocklen(drbg) : (outlen - len);
855 memcpy(outval + len, tmp, blocklen);
860 memset(tmp, 0, drbg_blocklen(drbg));
864 /* update function for Hash DRBG as defined in 10.1.1.2 / 10.1.1.3 */
865 static int drbg_hash_update(struct drbg_state *drbg, struct list_head *seed,
869 struct drbg_string data1, data2;
871 LIST_HEAD(datalist2);
872 unsigned char *V = drbg->scratchpad;
873 unsigned char prefix = DRBG_PREFIX1;
879 /* 10.1.1.3 step 1 */
880 memcpy(V, drbg->V, drbg_statelen(drbg));
881 drbg_string_fill(&data1, &prefix, 1);
882 list_add_tail(&data1.list, &datalist);
883 drbg_string_fill(&data2, V, drbg_statelen(drbg));
884 list_add_tail(&data2.list, &datalist);
886 list_splice_tail(seed, &datalist);
888 /* 10.1.1.2 / 10.1.1.3 step 2 and 3 */
889 ret = drbg_hash_df(drbg, drbg->V, drbg_statelen(drbg), &datalist);
893 /* 10.1.1.2 / 10.1.1.3 step 4 */
894 prefix = DRBG_PREFIX0;
895 drbg_string_fill(&data1, &prefix, 1);
896 list_add_tail(&data1.list, &datalist2);
897 drbg_string_fill(&data2, drbg->V, drbg_statelen(drbg));
898 list_add_tail(&data2.list, &datalist2);
899 /* 10.1.1.2 / 10.1.1.3 step 4 */
900 ret = drbg_hash_df(drbg, drbg->C, drbg_statelen(drbg), &datalist2);
903 memset(drbg->scratchpad, 0, drbg_statelen(drbg));
907 /* processing of additional information string for Hash DRBG */
908 static int drbg_hash_process_addtl(struct drbg_state *drbg,
909 struct list_head *addtl)
912 struct drbg_string data1, data2;
914 unsigned char prefix = DRBG_PREFIX2;
916 /* 10.1.1.4 step 2 */
917 if (!addtl || list_empty(addtl))
920 /* 10.1.1.4 step 2a */
921 drbg_string_fill(&data1, &prefix, 1);
922 drbg_string_fill(&data2, drbg->V, drbg_statelen(drbg));
923 list_add_tail(&data1.list, &datalist);
924 list_add_tail(&data2.list, &datalist);
925 list_splice_tail(addtl, &datalist);
926 ret = drbg_kcapi_hash(drbg, NULL, drbg->scratchpad, &datalist);
930 /* 10.1.1.4 step 2b */
931 drbg_add_buf(drbg->V, drbg_statelen(drbg),
932 drbg->scratchpad, drbg_blocklen(drbg));
935 memset(drbg->scratchpad, 0, drbg_blocklen(drbg));
939 /* Hashgen defined in 10.1.1.4 */
940 static int drbg_hash_hashgen(struct drbg_state *drbg,
946 unsigned char *src = drbg->scratchpad;
947 unsigned char *dst = drbg->scratchpad + drbg_statelen(drbg);
948 struct drbg_string data;
951 /* 10.1.1.4 step hashgen 2 */
952 memcpy(src, drbg->V, drbg_statelen(drbg));
954 drbg_string_fill(&data, src, drbg_statelen(drbg));
955 list_add_tail(&data.list, &datalist);
956 while (len < buflen) {
957 unsigned int outlen = 0;
958 /* 10.1.1.4 step hashgen 4.1 */
959 ret = drbg_kcapi_hash(drbg, NULL, dst, &datalist);
964 outlen = (drbg_blocklen(drbg) < (buflen - len)) ?
965 drbg_blocklen(drbg) : (buflen - len);
966 if (!drbg_fips_continuous_test(drbg, dst)) {
967 crypto_inc(src, drbg_statelen(drbg));
970 /* 10.1.1.4 step hashgen 4.2 */
971 memcpy(buf + len, dst, outlen);
973 /* 10.1.1.4 hashgen step 4.3 */
975 crypto_inc(src, drbg_statelen(drbg));
979 memset(drbg->scratchpad, 0,
980 (drbg_statelen(drbg) + drbg_blocklen(drbg)));
984 /* generate function for Hash DRBG as defined in 10.1.1.4 */
985 static int drbg_hash_generate(struct drbg_state *drbg,
986 unsigned char *buf, unsigned int buflen,
987 struct list_head *addtl)
992 unsigned char req[8];
995 unsigned char prefix = DRBG_PREFIX3;
996 struct drbg_string data1, data2;
999 /* 10.1.1.4 step 2 */
1000 ret = drbg_hash_process_addtl(drbg, addtl);
1003 /* 10.1.1.4 step 3 */
1004 len = drbg_hash_hashgen(drbg, buf, buflen);
1006 /* this is the value H as documented in 10.1.1.4 */
1007 /* 10.1.1.4 step 4 */
1008 drbg_string_fill(&data1, &prefix, 1);
1009 list_add_tail(&data1.list, &datalist);
1010 drbg_string_fill(&data2, drbg->V, drbg_statelen(drbg));
1011 list_add_tail(&data2.list, &datalist);
1012 ret = drbg_kcapi_hash(drbg, NULL, drbg->scratchpad, &datalist);
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));
1023 u.req_int = cpu_to_be64(drbg->reseed_ctr);
1024 drbg_add_buf(drbg->V, drbg_statelen(drbg), u.req, 8);
1027 memset(drbg->scratchpad, 0, drbg_blocklen(drbg));
1032 * scratchpad usage: as update and generate are used isolated, both
1033 * can use the scratchpad
1035 static 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,
1041 #endif /* CONFIG_CRYPTO_DRBG_HASH */
1043 /******************************************************************
1044 * Functions common for DRBG implementations
1045 ******************************************************************/
1047 static inline int __drbg_seed(struct drbg_state *drbg, struct list_head *seed,
1050 int ret = drbg->d_ops->update(drbg, seed, reseed);
1055 drbg->seeded = true;
1056 /* 10.1.1.2 / 10.1.1.3 step 5 */
1057 drbg->reseed_ctr = 1;
1062 static void drbg_async_seed(struct work_struct *work)
1064 struct drbg_string data;
1065 LIST_HEAD(seedlist);
1066 struct drbg_state *drbg = container_of(work, struct drbg_state,
1068 unsigned int entropylen = drbg_sec_strength(drbg->core->flags);
1069 unsigned char entropy[32];
1071 BUG_ON(!entropylen);
1072 BUG_ON(entropylen > sizeof(entropy));
1073 get_random_bytes(entropy, entropylen);
1075 drbg_string_fill(&data, entropy, entropylen);
1076 list_add_tail(&data.list, &seedlist);
1078 mutex_lock(&drbg->drbg_mutex);
1080 /* If nonblocking pool is initialized, deactivate Jitter RNG */
1081 crypto_free_rng(drbg->jent);
1084 /* Set seeded to false so that if __drbg_seed fails the
1085 * next generate call will trigger a reseed.
1087 drbg->seeded = false;
1089 __drbg_seed(drbg, &seedlist, true);
1092 drbg->reseed_threshold = drbg_max_requests(drbg);
1094 mutex_unlock(&drbg->drbg_mutex);
1096 memzero_explicit(entropy, entropylen);
1100 * Seeding or reseeding of the DRBG
1102 * @drbg: DRBG state struct
1103 * @pers: personalization / additional information buffer
1104 * @reseed: 0 for initial seed process, 1 for reseeding
1108 * error value otherwise
1110 static int drbg_seed(struct drbg_state *drbg, struct drbg_string *pers,
1114 unsigned char entropy[((32 + 16) * 2)];
1115 unsigned int entropylen = drbg_sec_strength(drbg->core->flags);
1116 struct drbg_string data1;
1117 LIST_HEAD(seedlist);
1119 /* 9.1 / 9.2 / 9.3.1 step 3 */
1120 if (pers && pers->len > (drbg_max_addtl(drbg))) {
1121 pr_devel("DRBG: personalization string too long %zu\n",
1126 if (list_empty(&drbg->test_data.list)) {
1127 drbg_string_fill(&data1, drbg->test_data.buf,
1128 drbg->test_data.len);
1129 pr_devel("DRBG: using test entropy\n");
1132 * Gather entropy equal to the security strength of the DRBG.
1133 * With a derivation function, a nonce is required in addition
1134 * to the entropy. A nonce must be at least 1/2 of the security
1135 * strength of the DRBG in size. Thus, entropy + nonce is 3/2
1136 * of the strength. The consideration of a nonce is only
1137 * applicable during initial seeding.
1139 BUG_ON(!entropylen);
1141 entropylen = ((entropylen + 1) / 2) * 3;
1142 BUG_ON((entropylen * 2) > sizeof(entropy));
1144 /* Get seed from in-kernel /dev/urandom */
1145 get_random_bytes(entropy, entropylen);
1148 drbg_string_fill(&data1, entropy, entropylen);
1149 pr_devel("DRBG: (re)seeding with %u bytes of entropy\n",
1152 /* Get seed from Jitter RNG */
1153 ret = crypto_rng_get_bytes(drbg->jent,
1154 entropy + entropylen,
1157 pr_devel("DRBG: jent failed with %d\n", ret);
1161 drbg_string_fill(&data1, entropy, entropylen * 2);
1162 pr_devel("DRBG: (re)seeding with %u bytes of entropy\n",
1166 list_add_tail(&data1.list, &seedlist);
1169 * concatenation of entropy with personalization str / addtl input)
1170 * the variable pers is directly handed in by the caller, so check its
1171 * contents whether it is appropriate
1173 if (pers && pers->buf && 0 < pers->len) {
1174 list_add_tail(&pers->list, &seedlist);
1175 pr_devel("DRBG: using personalization string\n");
1179 memset(drbg->V, 0, drbg_statelen(drbg));
1180 memset(drbg->C, 0, drbg_statelen(drbg));
1183 ret = __drbg_seed(drbg, &seedlist, reseed);
1185 memzero_explicit(entropy, entropylen * 2);
1190 /* Free all substructures in a DRBG state without the DRBG state structure */
1191 static inline void drbg_dealloc_state(struct drbg_state *drbg)
1199 kzfree(drbg->scratchpad);
1200 drbg->scratchpad = NULL;
1201 drbg->reseed_ctr = 0;
1204 #ifdef CONFIG_CRYPTO_FIPS
1207 drbg->fips_primed = false;
1212 * Allocate all sub-structures for a DRBG state.
1213 * The DRBG state structure must already be allocated.
1215 static inline int drbg_alloc_state(struct drbg_state *drbg)
1218 unsigned int sb_size = 0;
1220 switch (drbg->core->flags & DRBG_TYPE_MASK) {
1221 #ifdef CONFIG_CRYPTO_DRBG_HMAC
1223 drbg->d_ops = &drbg_hmac_ops;
1225 #endif /* CONFIG_CRYPTO_DRBG_HMAC */
1226 #ifdef CONFIG_CRYPTO_DRBG_HASH
1228 drbg->d_ops = &drbg_hash_ops;
1230 #endif /* CONFIG_CRYPTO_DRBG_HASH */
1231 #ifdef CONFIG_CRYPTO_DRBG_CTR
1233 drbg->d_ops = &drbg_ctr_ops;
1235 #endif /* CONFIG_CRYPTO_DRBG_CTR */
1241 drbg->V = kmalloc(drbg_statelen(drbg), GFP_KERNEL);
1244 drbg->C = kmalloc(drbg_statelen(drbg), GFP_KERNEL);
1247 #ifdef CONFIG_CRYPTO_FIPS
1248 drbg->prev = kmalloc(drbg_blocklen(drbg), GFP_KERNEL);
1251 drbg->fips_primed = false;
1253 /* scratchpad is only generated for CTR and Hash */
1254 if (drbg->core->flags & DRBG_HMAC)
1256 else if (drbg->core->flags & DRBG_CTR)
1257 sb_size = drbg_statelen(drbg) + drbg_blocklen(drbg) + /* temp */
1258 drbg_statelen(drbg) + /* df_data */
1259 drbg_blocklen(drbg) + /* pad */
1260 drbg_blocklen(drbg) + /* iv */
1261 drbg_statelen(drbg) + drbg_blocklen(drbg); /* temp */
1263 sb_size = drbg_statelen(drbg) + drbg_blocklen(drbg);
1266 drbg->scratchpad = kzalloc(sb_size, GFP_KERNEL);
1267 if (!drbg->scratchpad)
1274 drbg_dealloc_state(drbg);
1278 /*************************************************************************
1279 * DRBG interface functions
1280 *************************************************************************/
1283 * DRBG generate function as required by SP800-90A - this function
1284 * generates random numbers
1286 * @drbg DRBG state handle
1287 * @buf Buffer where to store the random numbers -- the buffer must already
1288 * be pre-allocated by caller
1289 * @buflen Length of output buffer - this value defines the number of random
1290 * bytes pulled from DRBG
1291 * @addtl Additional input that is mixed into state, may be NULL -- note
1292 * the entropy is pulled by the DRBG internally unconditionally
1293 * as defined in SP800-90A. The additional input is mixed into
1294 * the state in addition to the pulled entropy.
1296 * return: 0 when all bytes are generated; < 0 in case of an error
1298 static int drbg_generate(struct drbg_state *drbg,
1299 unsigned char *buf, unsigned int buflen,
1300 struct drbg_string *addtl)
1303 LIST_HEAD(addtllist);
1306 pr_devel("DRBG: not yet seeded\n");
1309 if (0 == buflen || !buf) {
1310 pr_devel("DRBG: no output buffer provided\n");
1313 if (addtl && NULL == addtl->buf && 0 < addtl->len) {
1314 pr_devel("DRBG: wrong format of additional information\n");
1320 if (buflen > (drbg_max_request_bytes(drbg))) {
1321 pr_devel("DRBG: requested random numbers too large %u\n",
1326 /* 9.3.1 step 3 is implicit with the chosen DRBG */
1329 if (addtl && addtl->len > (drbg_max_addtl(drbg))) {
1330 pr_devel("DRBG: additional information string too long %zu\n",
1334 /* 9.3.1 step 5 is implicit with the chosen DRBG */
1337 * 9.3.1 step 6 and 9 supplemented by 9.3.2 step c is implemented
1338 * here. The spec is a bit convoluted here, we make it simpler.
1340 if (drbg->reseed_threshold < drbg->reseed_ctr)
1341 drbg->seeded = false;
1343 if (drbg->pr || !drbg->seeded) {
1344 pr_devel("DRBG: reseeding before generation (prediction "
1345 "resistance: %s, state %s)\n",
1346 drbg->pr ? "true" : "false",
1347 drbg->seeded ? "seeded" : "unseeded");
1348 /* 9.3.1 steps 7.1 through 7.3 */
1349 len = drbg_seed(drbg, addtl, true);
1352 /* 9.3.1 step 7.4 */
1356 if (addtl && 0 < addtl->len)
1357 list_add_tail(&addtl->list, &addtllist);
1358 /* 9.3.1 step 8 and 10 */
1359 len = drbg->d_ops->generate(drbg, buf, buflen, &addtllist);
1361 /* 10.1.1.4 step 6, 10.1.2.5 step 7, 10.2.1.5.2 step 7 */
1367 * Section 11.3.3 requires to re-perform self tests after some
1368 * generated random numbers. The chosen value after which self
1369 * test is performed is arbitrary, but it should be reasonable.
1370 * However, we do not perform the self tests because of the following
1371 * reasons: it is mathematically impossible that the initial self tests
1372 * were successfully and the following are not. If the initial would
1373 * pass and the following would not, the kernel integrity is violated.
1374 * In this case, the entire kernel operation is questionable and it
1375 * is unlikely that the integrity violation only affects the
1376 * correct operation of the DRBG.
1378 * Albeit the following code is commented out, it is provided in
1379 * case somebody has a need to implement the test of 11.3.3.
1382 if (drbg->reseed_ctr && !(drbg->reseed_ctr % 4096)) {
1384 pr_devel("DRBG: start to perform self test\n");
1385 if (drbg->core->flags & DRBG_HMAC)
1386 err = alg_test("drbg_pr_hmac_sha256",
1387 "drbg_pr_hmac_sha256", 0, 0);
1388 else if (drbg->core->flags & DRBG_CTR)
1389 err = alg_test("drbg_pr_ctr_aes128",
1390 "drbg_pr_ctr_aes128", 0, 0);
1392 err = alg_test("drbg_pr_sha256",
1393 "drbg_pr_sha256", 0, 0);
1395 pr_err("DRBG: periodical self test failed\n");
1397 * uninstantiate implies that from now on, only errors
1398 * are returned when reusing this DRBG cipher handle
1400 drbg_uninstantiate(drbg);
1403 pr_devel("DRBG: self test successful\n");
1409 * All operations were successful, return 0 as mandated by
1410 * the kernel crypto API interface.
1418 * Wrapper around drbg_generate which can pull arbitrary long strings
1419 * from the DRBG without hitting the maximum request limitation.
1421 * Parameters: see drbg_generate
1422 * Return codes: see drbg_generate -- if one drbg_generate request fails,
1423 * the entire drbg_generate_long request fails
1425 static int drbg_generate_long(struct drbg_state *drbg,
1426 unsigned char *buf, unsigned int buflen,
1427 struct drbg_string *addtl)
1429 unsigned int len = 0;
1430 unsigned int slice = 0;
1433 unsigned int chunk = 0;
1434 slice = ((buflen - len) / drbg_max_request_bytes(drbg));
1435 chunk = slice ? drbg_max_request_bytes(drbg) : (buflen - len);
1436 mutex_lock(&drbg->drbg_mutex);
1437 err = drbg_generate(drbg, buf + len, chunk, addtl);
1438 mutex_unlock(&drbg->drbg_mutex);
1442 } while (slice > 0 && (len < buflen));
1446 static void drbg_schedule_async_seed(struct random_ready_callback *rdy)
1448 struct drbg_state *drbg = container_of(rdy, struct drbg_state,
1451 schedule_work(&drbg->seed_work);
1454 static int drbg_prepare_hrng(struct drbg_state *drbg)
1458 /* We do not need an HRNG in test mode. */
1459 if (list_empty(&drbg->test_data.list))
1462 INIT_WORK(&drbg->seed_work, drbg_async_seed);
1464 drbg->random_ready.owner = THIS_MODULE;
1465 drbg->random_ready.func = drbg_schedule_async_seed;
1467 err = add_random_ready_callback(&drbg->random_ready);
1478 drbg->random_ready.func = NULL;
1482 drbg->jent = crypto_alloc_rng("jitterentropy_rng", 0, 0);
1485 * Require frequent reseeds until the seed source is fully
1488 drbg->reseed_threshold = 50;
1494 * DRBG instantiation function as required by SP800-90A - this function
1495 * sets up the DRBG handle, performs the initial seeding and all sanity
1496 * checks required by SP800-90A
1498 * @drbg memory of state -- if NULL, new memory is allocated
1499 * @pers Personalization string that is mixed into state, may be NULL -- note
1500 * the entropy is pulled by the DRBG internally unconditionally
1501 * as defined in SP800-90A. The additional input is mixed into
1502 * the state in addition to the pulled entropy.
1503 * @coreref reference to core
1504 * @pr prediction resistance enabled
1508 * error value otherwise
1510 static int drbg_instantiate(struct drbg_state *drbg, struct drbg_string *pers,
1511 int coreref, bool pr)
1516 pr_devel("DRBG: Initializing DRBG core %d with prediction resistance "
1517 "%s\n", coreref, pr ? "enabled" : "disabled");
1518 mutex_lock(&drbg->drbg_mutex);
1520 /* 9.1 step 1 is implicit with the selected DRBG type */
1523 * 9.1 step 2 is implicit as caller can select prediction resistance
1524 * and the flag is copied into drbg->flags --
1525 * all DRBG types support prediction resistance
1528 /* 9.1 step 4 is implicit in drbg_sec_strength */
1531 drbg->core = &drbg_cores[coreref];
1533 drbg->seeded = false;
1534 drbg->reseed_threshold = drbg_max_requests(drbg);
1536 ret = drbg_alloc_state(drbg);
1541 if (drbg->d_ops->crypto_init(drbg))
1544 ret = drbg_prepare_hrng(drbg);
1546 goto free_everything;
1548 if (IS_ERR(drbg->jent)) {
1549 ret = PTR_ERR(drbg->jent);
1551 if (fips_enabled || ret != -ENOENT)
1552 goto free_everything;
1553 pr_info("DRBG: Continuing without Jitter RNG\n");
1559 ret = drbg_seed(drbg, pers, reseed);
1562 goto free_everything;
1564 mutex_unlock(&drbg->drbg_mutex);
1568 drbg_dealloc_state(drbg);
1570 mutex_unlock(&drbg->drbg_mutex);
1574 mutex_unlock(&drbg->drbg_mutex);
1575 drbg_uninstantiate(drbg);
1580 * DRBG uninstantiate function as required by SP800-90A - this function
1581 * frees all buffers and the DRBG handle
1583 * @drbg DRBG state handle
1588 static int drbg_uninstantiate(struct drbg_state *drbg)
1590 if (drbg->random_ready.func) {
1591 del_random_ready_callback(&drbg->random_ready);
1592 cancel_work_sync(&drbg->seed_work);
1593 crypto_free_rng(drbg->jent);
1598 drbg->d_ops->crypto_fini(drbg);
1599 drbg_dealloc_state(drbg);
1600 /* no scrubbing of test_data -- this shall survive an uninstantiate */
1605 * Helper function for setting the test data in the DRBG
1607 * @drbg DRBG state handle
1609 * @len test data length
1611 static void drbg_kcapi_set_entropy(struct crypto_rng *tfm,
1612 const u8 *data, unsigned int len)
1614 struct drbg_state *drbg = crypto_rng_ctx(tfm);
1616 mutex_lock(&drbg->drbg_mutex);
1617 drbg_string_fill(&drbg->test_data, data, len);
1618 mutex_unlock(&drbg->drbg_mutex);
1621 /***************************************************************
1622 * Kernel crypto API cipher invocations requested by DRBG
1623 ***************************************************************/
1625 #if defined(CONFIG_CRYPTO_DRBG_HASH) || defined(CONFIG_CRYPTO_DRBG_HMAC)
1627 struct shash_desc shash;
1631 static int drbg_init_hash_kernel(struct drbg_state *drbg)
1633 struct sdesc *sdesc;
1634 struct crypto_shash *tfm;
1636 tfm = crypto_alloc_shash(drbg->core->backend_cra_name, 0, 0);
1638 pr_info("DRBG: could not allocate digest TFM handle: %s\n",
1639 drbg->core->backend_cra_name);
1640 return PTR_ERR(tfm);
1642 BUG_ON(drbg_blocklen(drbg) != crypto_shash_digestsize(tfm));
1643 sdesc = kzalloc(sizeof(struct shash_desc) + crypto_shash_descsize(tfm),
1646 crypto_free_shash(tfm);
1650 sdesc->shash.tfm = tfm;
1651 sdesc->shash.flags = 0;
1652 drbg->priv_data = sdesc;
1656 static int drbg_fini_hash_kernel(struct drbg_state *drbg)
1658 struct sdesc *sdesc = (struct sdesc *)drbg->priv_data;
1660 crypto_free_shash(sdesc->shash.tfm);
1663 drbg->priv_data = NULL;
1667 static int drbg_kcapi_hash(struct drbg_state *drbg, const unsigned char *key,
1668 unsigned char *outval, const struct list_head *in)
1670 struct sdesc *sdesc = (struct sdesc *)drbg->priv_data;
1671 struct drbg_string *input = NULL;
1674 crypto_shash_setkey(sdesc->shash.tfm, key, drbg_statelen(drbg));
1675 crypto_shash_init(&sdesc->shash);
1676 list_for_each_entry(input, in, list)
1677 crypto_shash_update(&sdesc->shash, input->buf, input->len);
1678 return crypto_shash_final(&sdesc->shash, outval);
1680 #endif /* (CONFIG_CRYPTO_DRBG_HASH || CONFIG_CRYPTO_DRBG_HMAC) */
1682 #ifdef CONFIG_CRYPTO_DRBG_CTR
1683 static int drbg_init_sym_kernel(struct drbg_state *drbg)
1686 struct crypto_cipher *tfm;
1688 tfm = crypto_alloc_cipher(drbg->core->backend_cra_name, 0, 0);
1690 pr_info("DRBG: could not allocate cipher TFM handle: %s\n",
1691 drbg->core->backend_cra_name);
1692 return PTR_ERR(tfm);
1694 BUG_ON(drbg_blocklen(drbg) != crypto_cipher_blocksize(tfm));
1695 drbg->priv_data = tfm;
1699 static int drbg_fini_sym_kernel(struct drbg_state *drbg)
1701 struct crypto_cipher *tfm =
1702 (struct crypto_cipher *)drbg->priv_data;
1704 crypto_free_cipher(tfm);
1705 drbg->priv_data = NULL;
1709 static int drbg_kcapi_sym(struct drbg_state *drbg, const unsigned char *key,
1710 unsigned char *outval, const struct drbg_string *in)
1712 struct crypto_cipher *tfm =
1713 (struct crypto_cipher *)drbg->priv_data;
1715 crypto_cipher_setkey(tfm, key, (drbg_keylen(drbg)));
1716 /* there is only component in *in */
1717 BUG_ON(in->len < drbg_blocklen(drbg));
1718 crypto_cipher_encrypt_one(tfm, outval, in->buf);
1721 #endif /* CONFIG_CRYPTO_DRBG_CTR */
1723 /***************************************************************
1724 * Kernel crypto API interface to register DRBG
1725 ***************************************************************/
1728 * Look up the DRBG flags by given kernel crypto API cra_name
1729 * The code uses the drbg_cores definition to do this
1731 * @cra_name kernel crypto API cra_name
1732 * @coreref reference to integer which is filled with the pointer to
1733 * the applicable core
1734 * @pr reference for setting prediction resistance
1738 static inline void drbg_convert_tfm_core(const char *cra_driver_name,
1739 int *coreref, bool *pr)
1746 /* disassemble the names */
1747 if (!memcmp(cra_driver_name, "drbg_nopr_", 10)) {
1750 } else if (!memcmp(cra_driver_name, "drbg_pr_", 8)) {
1756 /* remove the first part */
1757 len = strlen(cra_driver_name) - start;
1758 for (i = 0; ARRAY_SIZE(drbg_cores) > i; i++) {
1759 if (!memcmp(cra_driver_name + start, drbg_cores[i].cra_name,
1767 static int drbg_kcapi_init(struct crypto_tfm *tfm)
1769 struct drbg_state *drbg = crypto_tfm_ctx(tfm);
1771 mutex_init(&drbg->drbg_mutex);
1776 static void drbg_kcapi_cleanup(struct crypto_tfm *tfm)
1778 drbg_uninstantiate(crypto_tfm_ctx(tfm));
1782 * Generate random numbers invoked by the kernel crypto API:
1783 * The API of the kernel crypto API is extended as follows:
1785 * src is additional input supplied to the RNG.
1786 * slen is the length of src.
1787 * dst is the output buffer where random data is to be stored.
1788 * dlen is the length of dst.
1790 static int drbg_kcapi_random(struct crypto_rng *tfm,
1791 const u8 *src, unsigned int slen,
1792 u8 *dst, unsigned int dlen)
1794 struct drbg_state *drbg = crypto_rng_ctx(tfm);
1795 struct drbg_string *addtl = NULL;
1796 struct drbg_string string;
1799 /* linked list variable is now local to allow modification */
1800 drbg_string_fill(&string, src, slen);
1804 return drbg_generate_long(drbg, dst, dlen, addtl);
1808 * Seed the DRBG invoked by the kernel crypto API
1810 static int drbg_kcapi_seed(struct crypto_rng *tfm,
1811 const u8 *seed, unsigned int slen)
1813 struct drbg_state *drbg = crypto_rng_ctx(tfm);
1814 struct crypto_tfm *tfm_base = crypto_rng_tfm(tfm);
1816 struct drbg_string string;
1817 struct drbg_string *seed_string = NULL;
1820 drbg_convert_tfm_core(crypto_tfm_alg_driver_name(tfm_base), &coreref,
1823 drbg_string_fill(&string, seed, slen);
1824 seed_string = &string;
1827 return drbg_instantiate(drbg, seed_string, coreref, pr);
1830 /***************************************************************
1831 * Kernel module: code to load the module
1832 ***************************************************************/
1835 * Tests as defined in 11.3.2 in addition to the cipher tests: testing
1836 * of the error handling.
1838 * Note: testing of failing seed source as defined in 11.3.2 is not applicable
1839 * as seed source of get_random_bytes does not fail.
1841 * Note 2: There is no sensible way of testing the reseed counter
1842 * enforcement, so skip it.
1844 static inline int __init drbg_healthcheck_sanity(void)
1847 #define OUTBUFLEN 16
1848 unsigned char buf[OUTBUFLEN];
1849 struct drbg_state *drbg = NULL;
1854 struct drbg_string addtl;
1855 size_t max_addtllen, max_request_bytes;
1857 /* only perform test in FIPS mode */
1861 #ifdef CONFIG_CRYPTO_DRBG_CTR
1862 drbg_convert_tfm_core("drbg_nopr_ctr_aes128", &coreref, &pr);
1863 #elif defined CONFIG_CRYPTO_DRBG_HASH
1864 drbg_convert_tfm_core("drbg_nopr_sha256", &coreref, &pr);
1866 drbg_convert_tfm_core("drbg_nopr_hmac_sha256", &coreref, &pr);
1869 drbg = kzalloc(sizeof(struct drbg_state), GFP_KERNEL);
1873 mutex_init(&drbg->drbg_mutex);
1876 * if the following tests fail, it is likely that there is a buffer
1877 * overflow as buf is much smaller than the requested or provided
1878 * string lengths -- in case the error handling does not succeed
1879 * we may get an OOPS. And we want to get an OOPS as this is a
1883 /* get a valid instance of DRBG for following tests */
1884 ret = drbg_instantiate(drbg, NULL, coreref, pr);
1889 max_addtllen = drbg_max_addtl(drbg);
1890 max_request_bytes = drbg_max_request_bytes(drbg);
1891 drbg_string_fill(&addtl, buf, max_addtllen + 1);
1892 /* overflow addtllen with additonal info string */
1893 len = drbg_generate(drbg, buf, OUTBUFLEN, &addtl);
1895 /* overflow max_bits */
1896 len = drbg_generate(drbg, buf, (max_request_bytes + 1), NULL);
1898 drbg_uninstantiate(drbg);
1900 /* overflow max addtllen with personalization string */
1901 ret = drbg_instantiate(drbg, &addtl, coreref, pr);
1903 /* all tests passed */
1906 pr_devel("DRBG: Sanity tests for failure code paths successfully "
1909 drbg_uninstantiate(drbg);
1915 static struct rng_alg drbg_algs[22];
1918 * Fill the array drbg_algs used to register the different DRBGs
1919 * with the kernel crypto API. To fill the array, the information
1920 * from drbg_cores[] is used.
1922 static inline void __init drbg_fill_array(struct rng_alg *alg,
1923 const struct drbg_core *core, int pr)
1926 static int priority = 200;
1928 memcpy(alg->base.cra_name, "stdrng", 6);
1930 memcpy(alg->base.cra_driver_name, "drbg_pr_", 8);
1933 memcpy(alg->base.cra_driver_name, "drbg_nopr_", 10);
1936 memcpy(alg->base.cra_driver_name + pos, core->cra_name,
1937 strlen(core->cra_name));
1939 alg->base.cra_priority = priority;
1942 * If FIPS mode enabled, the selected DRBG shall have the
1943 * highest cra_priority over other stdrng instances to ensure
1947 alg->base.cra_priority += 200;
1949 alg->base.cra_ctxsize = sizeof(struct drbg_state);
1950 alg->base.cra_module = THIS_MODULE;
1951 alg->base.cra_init = drbg_kcapi_init;
1952 alg->base.cra_exit = drbg_kcapi_cleanup;
1953 alg->generate = drbg_kcapi_random;
1954 alg->seed = drbg_kcapi_seed;
1955 alg->set_ent = drbg_kcapi_set_entropy;
1959 static int __init drbg_init(void)
1961 unsigned int i = 0; /* pointer to drbg_algs */
1962 unsigned int j = 0; /* pointer to drbg_cores */
1965 ret = drbg_healthcheck_sanity();
1969 if (ARRAY_SIZE(drbg_cores) * 2 > ARRAY_SIZE(drbg_algs)) {
1970 pr_info("DRBG: Cannot register all DRBG types"
1971 "(slots needed: %zu, slots available: %zu)\n",
1972 ARRAY_SIZE(drbg_cores) * 2, ARRAY_SIZE(drbg_algs));
1977 * each DRBG definition can be used with PR and without PR, thus
1978 * we instantiate each DRBG in drbg_cores[] twice.
1980 * As the order of placing them into the drbg_algs array matters
1981 * (the later DRBGs receive a higher cra_priority) we register the
1982 * prediction resistance DRBGs first as the should not be too
1985 for (j = 0; ARRAY_SIZE(drbg_cores) > j; j++, i++)
1986 drbg_fill_array(&drbg_algs[i], &drbg_cores[j], 1);
1987 for (j = 0; ARRAY_SIZE(drbg_cores) > j; j++, i++)
1988 drbg_fill_array(&drbg_algs[i], &drbg_cores[j], 0);
1989 return crypto_register_rngs(drbg_algs, (ARRAY_SIZE(drbg_cores) * 2));
1992 static void __exit drbg_exit(void)
1994 crypto_unregister_rngs(drbg_algs, (ARRAY_SIZE(drbg_cores) * 2));
1997 module_init(drbg_init);
1998 module_exit(drbg_exit);
1999 #ifndef CRYPTO_DRBG_HASH_STRING
2000 #define CRYPTO_DRBG_HASH_STRING ""
2002 #ifndef CRYPTO_DRBG_HMAC_STRING
2003 #define CRYPTO_DRBG_HMAC_STRING ""
2005 #ifndef CRYPTO_DRBG_CTR_STRING
2006 #define CRYPTO_DRBG_CTR_STRING ""
2008 MODULE_LICENSE("GPL");
2009 MODULE_AUTHOR("Stephan Mueller <smueller@chronox.de>");
2010 MODULE_DESCRIPTION("NIST SP800-90A Deterministic Random Bit Generator (DRBG) "
2011 "using following cores: "
2012 CRYPTO_DRBG_HASH_STRING
2013 CRYPTO_DRBG_HMAC_STRING
2014 CRYPTO_DRBG_CTR_STRING);
2015 MODULE_ALIAS_CRYPTO("stdrng");