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>
102 /***************************************************************
103 * Backend cipher definitions available to DRBG
104 ***************************************************************/
107 * The order of the DRBG definitions here matter: every DRBG is registered
108 * as stdrng. Each DRBG receives an increasing cra_priority values the later
109 * they are defined in this array (see drbg_fill_array).
111 * HMAC DRBGs are favored over Hash DRBGs over CTR DRBGs, and
112 * the SHA256 / AES 256 over other ciphers. Thus, the favored
113 * DRBGs are the latest entries in this array.
115 static const struct drbg_core drbg_cores
[] = {
116 #ifdef CONFIG_CRYPTO_DRBG_CTR
118 .flags
= DRBG_CTR
| DRBG_STRENGTH128
,
119 .statelen
= 32, /* 256 bits as defined in 10.2.1 */
120 .blocklen_bytes
= 16,
121 .cra_name
= "ctr_aes128",
122 .backend_cra_name
= "aes",
124 .flags
= DRBG_CTR
| DRBG_STRENGTH192
,
125 .statelen
= 40, /* 320 bits as defined in 10.2.1 */
126 .blocklen_bytes
= 16,
127 .cra_name
= "ctr_aes192",
128 .backend_cra_name
= "aes",
130 .flags
= DRBG_CTR
| DRBG_STRENGTH256
,
131 .statelen
= 48, /* 384 bits as defined in 10.2.1 */
132 .blocklen_bytes
= 16,
133 .cra_name
= "ctr_aes256",
134 .backend_cra_name
= "aes",
136 #endif /* CONFIG_CRYPTO_DRBG_CTR */
137 #ifdef CONFIG_CRYPTO_DRBG_HASH
139 .flags
= DRBG_HASH
| DRBG_STRENGTH128
,
140 .statelen
= 55, /* 440 bits */
141 .blocklen_bytes
= 20,
143 .backend_cra_name
= "sha1",
145 .flags
= DRBG_HASH
| DRBG_STRENGTH256
,
146 .statelen
= 111, /* 888 bits */
147 .blocklen_bytes
= 48,
148 .cra_name
= "sha384",
149 .backend_cra_name
= "sha384",
151 .flags
= DRBG_HASH
| DRBG_STRENGTH256
,
152 .statelen
= 111, /* 888 bits */
153 .blocklen_bytes
= 64,
154 .cra_name
= "sha512",
155 .backend_cra_name
= "sha512",
157 .flags
= DRBG_HASH
| DRBG_STRENGTH256
,
158 .statelen
= 55, /* 440 bits */
159 .blocklen_bytes
= 32,
160 .cra_name
= "sha256",
161 .backend_cra_name
= "sha256",
163 #endif /* CONFIG_CRYPTO_DRBG_HASH */
164 #ifdef CONFIG_CRYPTO_DRBG_HMAC
166 .flags
= DRBG_HMAC
| DRBG_STRENGTH128
,
167 .statelen
= 20, /* block length of cipher */
168 .blocklen_bytes
= 20,
169 .cra_name
= "hmac_sha1",
170 .backend_cra_name
= "hmac(sha1)",
172 .flags
= DRBG_HMAC
| DRBG_STRENGTH256
,
173 .statelen
= 48, /* block length of cipher */
174 .blocklen_bytes
= 48,
175 .cra_name
= "hmac_sha384",
176 .backend_cra_name
= "hmac(sha384)",
178 .flags
= DRBG_HMAC
| DRBG_STRENGTH256
,
179 .statelen
= 64, /* block length of cipher */
180 .blocklen_bytes
= 64,
181 .cra_name
= "hmac_sha512",
182 .backend_cra_name
= "hmac(sha512)",
184 .flags
= DRBG_HMAC
| DRBG_STRENGTH256
,
185 .statelen
= 32, /* block length of cipher */
186 .blocklen_bytes
= 32,
187 .cra_name
= "hmac_sha256",
188 .backend_cra_name
= "hmac(sha256)",
190 #endif /* CONFIG_CRYPTO_DRBG_HMAC */
193 /******************************************************************
194 * Generic helper functions
195 ******************************************************************/
198 * Return strength of DRBG according to SP800-90A section 8.4
200 * @flags DRBG flags reference
202 * Return: normalized strength in *bytes* value or 32 as default
203 * to counter programming errors
205 static inline unsigned short drbg_sec_strength(drbg_flag_t flags
)
207 switch (flags
& DRBG_STRENGTH_MASK
) {
208 case DRBG_STRENGTH128
:
210 case DRBG_STRENGTH192
:
212 case DRBG_STRENGTH256
:
220 * FIPS 140-2 continuous self test
221 * The test is performed on the result of one round of the output
222 * function. Thus, the function implicitly knows the size of the
226 * @buf output buffer of random data to be checked
232 static bool drbg_fips_continuous_test(struct drbg_state
*drbg
,
233 const unsigned char *buf
)
235 #ifdef CONFIG_CRYPTO_FIPS
237 /* skip test if we test the overall system */
240 /* only perform test in FIPS mode */
241 if (0 == fips_enabled
)
243 if (!drbg
->fips_primed
) {
244 /* Priming of FIPS test */
245 memcpy(drbg
->prev
, buf
, drbg_blocklen(drbg
));
246 drbg
->fips_primed
= true;
247 /* return false due to priming, i.e. another round is needed */
250 ret
= memcmp(drbg
->prev
, buf
, drbg_blocklen(drbg
));
252 panic("DRBG continuous self test failed\n");
253 memcpy(drbg
->prev
, buf
, drbg_blocklen(drbg
));
254 /* the test shall pass when the two compared values are not equal */
258 #endif /* CONFIG_CRYPTO_FIPS */
262 * Convert an integer into a byte representation of this integer.
263 * The byte representation is big-endian
265 * @val value to be converted
266 * @buf buffer holding the converted integer -- caller must ensure that
267 * buffer size is at least 32 bit
269 #if (defined(CONFIG_CRYPTO_DRBG_HASH) || defined(CONFIG_CRYPTO_DRBG_CTR))
270 static inline void drbg_cpu_to_be32(__u32 val
, unsigned char *buf
)
275 struct s
*conversion
= (struct s
*) buf
;
277 conversion
->conv
= cpu_to_be32(val
);
279 #endif /* defined(CONFIG_CRYPTO_DRBG_HASH) || defined(CONFIG_CRYPTO_DRBG_CTR) */
281 /******************************************************************
282 * CTR DRBG callback functions
283 ******************************************************************/
285 #ifdef CONFIG_CRYPTO_DRBG_CTR
286 #define CRYPTO_DRBG_CTR_STRING "CTR "
287 MODULE_ALIAS_CRYPTO("drbg_pr_ctr_aes256");
288 MODULE_ALIAS_CRYPTO("drbg_nopr_ctr_aes256");
289 MODULE_ALIAS_CRYPTO("drbg_pr_ctr_aes192");
290 MODULE_ALIAS_CRYPTO("drbg_nopr_ctr_aes192");
291 MODULE_ALIAS_CRYPTO("drbg_pr_ctr_aes128");
292 MODULE_ALIAS_CRYPTO("drbg_nopr_ctr_aes128");
294 static int drbg_kcapi_sym(struct drbg_state
*drbg
, const unsigned char *key
,
295 unsigned char *outval
, const struct drbg_string
*in
);
296 static int drbg_init_sym_kernel(struct drbg_state
*drbg
);
297 static int drbg_fini_sym_kernel(struct drbg_state
*drbg
);
299 /* BCC function for CTR DRBG as defined in 10.4.3 */
300 static int drbg_ctr_bcc(struct drbg_state
*drbg
,
301 unsigned char *out
, const unsigned char *key
,
302 struct list_head
*in
)
305 struct drbg_string
*curr
= NULL
;
306 struct drbg_string data
;
309 drbg_string_fill(&data
, out
, drbg_blocklen(drbg
));
311 /* 10.4.3 step 2 / 4 */
312 list_for_each_entry(curr
, in
, list
) {
313 const unsigned char *pos
= curr
->buf
;
314 size_t len
= curr
->len
;
315 /* 10.4.3 step 4.1 */
317 /* 10.4.3 step 4.2 */
318 if (drbg_blocklen(drbg
) == cnt
) {
320 ret
= drbg_kcapi_sym(drbg
, key
, out
, &data
);
330 /* 10.4.3 step 4.2 for last block */
332 ret
= drbg_kcapi_sym(drbg
, key
, out
, &data
);
338 * scratchpad usage: drbg_ctr_update is interlinked with drbg_ctr_df
339 * (and drbg_ctr_bcc, but this function does not need any temporary buffers),
340 * the scratchpad is used as follows:
343 * start: drbg->scratchpad
344 * length: drbg_statelen(drbg) + drbg_blocklen(drbg)
345 * note: the cipher writing into this variable works
346 * blocklen-wise. Now, when the statelen is not a multiple
347 * of blocklen, the generateion loop below "spills over"
348 * by at most blocklen. Thus, we need to give sufficient
351 * start: drbg->scratchpad +
352 * drbg_statelen(drbg) + drbg_blocklen(drbg)
353 * length: drbg_statelen(drbg)
357 * start: df_data + drbg_statelen(drbg)
358 * length: drbg_blocklen(drbg)
360 * start: pad + drbg_blocklen(drbg)
361 * length: drbg_blocklen(drbg)
363 * start: iv + drbg_blocklen(drbg)
364 * length: drbg_satelen(drbg) + drbg_blocklen(drbg)
365 * note: temp is the buffer that the BCC function operates
366 * on. BCC operates blockwise. drbg_statelen(drbg)
367 * is sufficient when the DRBG state length is a multiple
368 * of the block size. For AES192 (and maybe other ciphers)
369 * this is not correct and the length for temp is
370 * insufficient (yes, that also means for such ciphers,
371 * the final output of all BCC rounds are truncated).
372 * Therefore, add drbg_blocklen(drbg) to cover all
376 /* Derivation Function for CTR DRBG as defined in 10.4.2 */
377 static int drbg_ctr_df(struct drbg_state
*drbg
,
378 unsigned char *df_data
, size_t bytes_to_return
,
379 struct list_head
*seedlist
)
382 unsigned char L_N
[8];
384 struct drbg_string S1
, S2
, S4
, cipherin
;
386 unsigned char *pad
= df_data
+ drbg_statelen(drbg
);
387 unsigned char *iv
= pad
+ drbg_blocklen(drbg
);
388 unsigned char *temp
= iv
+ drbg_blocklen(drbg
);
390 unsigned int templen
= 0;
394 const unsigned char *K
= (unsigned char *)
395 "\x00\x01\x02\x03\x04\x05\x06\x07"
396 "\x08\x09\x0a\x0b\x0c\x0d\x0e\x0f"
397 "\x10\x11\x12\x13\x14\x15\x16\x17"
398 "\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f";
400 size_t generated_len
= 0;
402 struct drbg_string
*seed
= NULL
;
404 memset(pad
, 0, drbg_blocklen(drbg
));
405 memset(iv
, 0, drbg_blocklen(drbg
));
407 /* 10.4.2 step 1 is implicit as we work byte-wise */
410 if ((512/8) < bytes_to_return
)
413 /* 10.4.2 step 2 -- calculate the entire length of all input data */
414 list_for_each_entry(seed
, seedlist
, list
)
415 inputlen
+= seed
->len
;
416 drbg_cpu_to_be32(inputlen
, &L_N
[0]);
419 drbg_cpu_to_be32(bytes_to_return
, &L_N
[4]);
421 /* 10.4.2 step 5: length is L_N, input_string, one byte, padding */
422 padlen
= (inputlen
+ sizeof(L_N
) + 1) % (drbg_blocklen(drbg
));
423 /* wrap the padlen appropriately */
425 padlen
= drbg_blocklen(drbg
) - padlen
;
427 * pad / padlen contains the 0x80 byte and the following zero bytes.
428 * As the calculated padlen value only covers the number of zero
429 * bytes, this value has to be incremented by one for the 0x80 byte.
434 /* 10.4.2 step 4 -- first fill the linked list and then order it */
435 drbg_string_fill(&S1
, iv
, drbg_blocklen(drbg
));
436 list_add_tail(&S1
.list
, &bcc_list
);
437 drbg_string_fill(&S2
, L_N
, sizeof(L_N
));
438 list_add_tail(&S2
.list
, &bcc_list
);
439 list_splice_tail(seedlist
, &bcc_list
);
440 drbg_string_fill(&S4
, pad
, padlen
);
441 list_add_tail(&S4
.list
, &bcc_list
);
444 while (templen
< (drbg_keylen(drbg
) + (drbg_blocklen(drbg
)))) {
446 * 10.4.2 step 9.1 - the padding is implicit as the buffer
447 * holds zeros after allocation -- even the increment of i
448 * is irrelevant as the increment remains within length of i
450 drbg_cpu_to_be32(i
, iv
);
451 /* 10.4.2 step 9.2 -- BCC and concatenation with temp */
452 ret
= drbg_ctr_bcc(drbg
, temp
+ templen
, K
, &bcc_list
);
455 /* 10.4.2 step 9.3 */
457 templen
+= drbg_blocklen(drbg
);
461 X
= temp
+ (drbg_keylen(drbg
));
462 drbg_string_fill(&cipherin
, X
, drbg_blocklen(drbg
));
464 /* 10.4.2 step 12: overwriting of outval is implemented in next step */
467 while (generated_len
< bytes_to_return
) {
470 * 10.4.2 step 13.1: the truncation of the key length is
471 * implicit as the key is only drbg_blocklen in size based on
472 * the implementation of the cipher function callback
474 ret
= drbg_kcapi_sym(drbg
, temp
, X
, &cipherin
);
477 blocklen
= (drbg_blocklen(drbg
) <
478 (bytes_to_return
- generated_len
)) ?
479 drbg_blocklen(drbg
) :
480 (bytes_to_return
- generated_len
);
481 /* 10.4.2 step 13.2 and 14 */
482 memcpy(df_data
+ generated_len
, X
, blocklen
);
483 generated_len
+= blocklen
;
489 memset(iv
, 0, drbg_blocklen(drbg
));
490 memset(temp
, 0, drbg_statelen(drbg
) + drbg_blocklen(drbg
));
491 memset(pad
, 0, drbg_blocklen(drbg
));
496 * update function of CTR DRBG as defined in 10.2.1.2
498 * The reseed variable has an enhanced meaning compared to the update
499 * functions of the other DRBGs as follows:
500 * 0 => initial seed from initialization
501 * 1 => reseed via drbg_seed
502 * 2 => first invocation from drbg_ctr_update when addtl is present. In
503 * this case, the df_data scratchpad is not deleted so that it is
504 * available for another calls to prevent calling the DF function
506 * 3 => second invocation from drbg_ctr_update. When the update function
507 * was called with addtl, the df_data memory already contains the
508 * DFed addtl information and we do not need to call DF again.
510 static int drbg_ctr_update(struct drbg_state
*drbg
, struct list_head
*seed
,
514 /* 10.2.1.2 step 1 */
515 unsigned char *temp
= drbg
->scratchpad
;
516 unsigned char *df_data
= drbg
->scratchpad
+ drbg_statelen(drbg
) +
518 unsigned char *temp_p
, *df_data_p
; /* pointer to iterate over buffers */
519 unsigned int len
= 0;
520 struct drbg_string cipherin
;
523 memset(df_data
, 0, drbg_statelen(drbg
));
525 /* 10.2.1.3.2 step 2 and 10.2.1.4.2 step 2 */
527 ret
= drbg_ctr_df(drbg
, df_data
, drbg_statelen(drbg
), seed
);
532 drbg_string_fill(&cipherin
, drbg
->V
, drbg_blocklen(drbg
));
534 * 10.2.1.3.2 steps 2 and 3 are already covered as the allocation
535 * zeroizes all memory during initialization
537 while (len
< (drbg_statelen(drbg
))) {
538 /* 10.2.1.2 step 2.1 */
539 crypto_inc(drbg
->V
, drbg_blocklen(drbg
));
541 * 10.2.1.2 step 2.2 */
542 ret
= drbg_kcapi_sym(drbg
, drbg
->C
, temp
+ len
, &cipherin
);
545 /* 10.2.1.2 step 2.3 and 3 */
546 len
+= drbg_blocklen(drbg
);
549 /* 10.2.1.2 step 4 */
552 for (len
= 0; len
< drbg_statelen(drbg
); len
++) {
553 *temp_p
^= *df_data_p
;
554 df_data_p
++; temp_p
++;
557 /* 10.2.1.2 step 5 */
558 memcpy(drbg
->C
, temp
, drbg_keylen(drbg
));
559 /* 10.2.1.2 step 6 */
560 memcpy(drbg
->V
, temp
+ drbg_keylen(drbg
), drbg_blocklen(drbg
));
564 memset(temp
, 0, drbg_statelen(drbg
) + drbg_blocklen(drbg
));
566 memset(df_data
, 0, drbg_statelen(drbg
));
571 * scratchpad use: drbg_ctr_update is called independently from
572 * drbg_ctr_extract_bytes. Therefore, the scratchpad is reused
574 /* Generate function of CTR DRBG as defined in 10.2.1.5.2 */
575 static int drbg_ctr_generate(struct drbg_state
*drbg
,
576 unsigned char *buf
, unsigned int buflen
,
577 struct list_head
*addtl
)
581 struct drbg_string data
;
583 /* 10.2.1.5.2 step 2 */
584 if (addtl
&& !list_empty(addtl
)) {
585 ret
= drbg_ctr_update(drbg
, addtl
, 2);
590 /* 10.2.1.5.2 step 4.1 */
591 crypto_inc(drbg
->V
, drbg_blocklen(drbg
));
592 drbg_string_fill(&data
, drbg
->V
, drbg_blocklen(drbg
));
593 while (len
< buflen
) {
595 /* 10.2.1.5.2 step 4.2 */
596 ret
= drbg_kcapi_sym(drbg
, drbg
->C
, drbg
->scratchpad
, &data
);
601 outlen
= (drbg_blocklen(drbg
) < (buflen
- len
)) ?
602 drbg_blocklen(drbg
) : (buflen
- len
);
603 if (!drbg_fips_continuous_test(drbg
, drbg
->scratchpad
)) {
604 /* 10.2.1.5.2 step 6 */
605 crypto_inc(drbg
->V
, drbg_blocklen(drbg
));
608 /* 10.2.1.5.2 step 4.3 */
609 memcpy(buf
+ len
, drbg
->scratchpad
, outlen
);
611 /* 10.2.1.5.2 step 6 */
613 crypto_inc(drbg
->V
, drbg_blocklen(drbg
));
616 /* 10.2.1.5.2 step 6 */
617 ret
= drbg_ctr_update(drbg
, NULL
, 3);
622 memset(drbg
->scratchpad
, 0, drbg_blocklen(drbg
));
626 static struct drbg_state_ops drbg_ctr_ops
= {
627 .update
= drbg_ctr_update
,
628 .generate
= drbg_ctr_generate
,
629 .crypto_init
= drbg_init_sym_kernel
,
630 .crypto_fini
= drbg_fini_sym_kernel
,
632 #endif /* CONFIG_CRYPTO_DRBG_CTR */
634 /******************************************************************
635 * HMAC DRBG callback functions
636 ******************************************************************/
638 #if defined(CONFIG_CRYPTO_DRBG_HASH) || defined(CONFIG_CRYPTO_DRBG_HMAC)
639 static int drbg_kcapi_hash(struct drbg_state
*drbg
, const unsigned char *key
,
640 unsigned char *outval
, const struct list_head
*in
);
641 static int drbg_init_hash_kernel(struct drbg_state
*drbg
);
642 static int drbg_fini_hash_kernel(struct drbg_state
*drbg
);
643 #endif /* (CONFIG_CRYPTO_DRBG_HASH || CONFIG_CRYPTO_DRBG_HMAC) */
645 #ifdef CONFIG_CRYPTO_DRBG_HMAC
646 #define CRYPTO_DRBG_HMAC_STRING "HMAC "
647 MODULE_ALIAS_CRYPTO("drbg_pr_hmac_sha512");
648 MODULE_ALIAS_CRYPTO("drbg_nopr_hmac_sha512");
649 MODULE_ALIAS_CRYPTO("drbg_pr_hmac_sha384");
650 MODULE_ALIAS_CRYPTO("drbg_nopr_hmac_sha384");
651 MODULE_ALIAS_CRYPTO("drbg_pr_hmac_sha256");
652 MODULE_ALIAS_CRYPTO("drbg_nopr_hmac_sha256");
653 MODULE_ALIAS_CRYPTO("drbg_pr_hmac_sha1");
654 MODULE_ALIAS_CRYPTO("drbg_nopr_hmac_sha1");
656 /* update function of HMAC DRBG as defined in 10.1.2.2 */
657 static int drbg_hmac_update(struct drbg_state
*drbg
, struct list_head
*seed
,
662 struct drbg_string seed1
, seed2
, vdata
;
664 LIST_HEAD(vdatalist
);
667 /* 10.1.2.3 step 2 -- memset(0) of C is implicit with kzalloc */
668 memset(drbg
->V
, 1, drbg_statelen(drbg
));
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
, drbg
->C
, &seedlist
);
692 /* 10.1.2.2 step 2 and 5 -- HMAC for V */
693 ret
= drbg_kcapi_hash(drbg
, drbg
->C
, drbg
->V
, &vdatalist
);
697 /* 10.1.2.2 step 3 */
705 /* generate function of HMAC DRBG as defined in 10.1.2.5 */
706 static int drbg_hmac_generate(struct drbg_state
*drbg
,
709 struct list_head
*addtl
)
713 struct drbg_string data
;
716 /* 10.1.2.5 step 2 */
717 if (addtl
&& !list_empty(addtl
)) {
718 ret
= drbg_hmac_update(drbg
, addtl
, 1);
723 drbg_string_fill(&data
, drbg
->V
, drbg_statelen(drbg
));
724 list_add_tail(&data
.list
, &datalist
);
725 while (len
< buflen
) {
726 unsigned int outlen
= 0;
727 /* 10.1.2.5 step 4.1 */
728 ret
= drbg_kcapi_hash(drbg
, drbg
->C
, drbg
->V
, &datalist
);
731 outlen
= (drbg_blocklen(drbg
) < (buflen
- len
)) ?
732 drbg_blocklen(drbg
) : (buflen
- len
);
733 if (!drbg_fips_continuous_test(drbg
, drbg
->V
))
736 /* 10.1.2.5 step 4.2 */
737 memcpy(buf
+ len
, drbg
->V
, outlen
);
741 /* 10.1.2.5 step 6 */
742 if (addtl
&& !list_empty(addtl
))
743 ret
= drbg_hmac_update(drbg
, addtl
, 1);
745 ret
= drbg_hmac_update(drbg
, NULL
, 1);
752 static struct drbg_state_ops drbg_hmac_ops
= {
753 .update
= drbg_hmac_update
,
754 .generate
= drbg_hmac_generate
,
755 .crypto_init
= drbg_init_hash_kernel
,
756 .crypto_fini
= drbg_fini_hash_kernel
,
758 #endif /* CONFIG_CRYPTO_DRBG_HMAC */
760 /******************************************************************
761 * Hash DRBG callback functions
762 ******************************************************************/
764 #ifdef CONFIG_CRYPTO_DRBG_HASH
765 #define CRYPTO_DRBG_HASH_STRING "HASH "
766 MODULE_ALIAS_CRYPTO("drbg_pr_sha512");
767 MODULE_ALIAS_CRYPTO("drbg_nopr_sha512");
768 MODULE_ALIAS_CRYPTO("drbg_pr_sha384");
769 MODULE_ALIAS_CRYPTO("drbg_nopr_sha384");
770 MODULE_ALIAS_CRYPTO("drbg_pr_sha256");
771 MODULE_ALIAS_CRYPTO("drbg_nopr_sha256");
772 MODULE_ALIAS_CRYPTO("drbg_pr_sha1");
773 MODULE_ALIAS_CRYPTO("drbg_nopr_sha1");
778 * @dst buffer to increment
781 static inline void drbg_add_buf(unsigned char *dst
, size_t dstlen
,
782 const unsigned char *add
, size_t addlen
)
784 /* implied: dstlen > addlen */
785 unsigned char *dstptr
;
786 const unsigned char *addptr
;
787 unsigned int remainder
= 0;
790 dstptr
= dst
+ (dstlen
-1);
791 addptr
= add
+ (addlen
-1);
793 remainder
+= *dstptr
+ *addptr
;
794 *dstptr
= remainder
& 0xff;
796 len
--; dstptr
--; addptr
--;
798 len
= dstlen
- addlen
;
799 while (len
&& remainder
> 0) {
800 remainder
= *dstptr
+ 1;
801 *dstptr
= remainder
& 0xff;
808 * scratchpad usage: as drbg_hash_update and drbg_hash_df are used
809 * interlinked, the scratchpad is used as follows:
811 * start: drbg->scratchpad
812 * length: drbg_statelen(drbg)
814 * start: drbg->scratchpad + drbg_statelen(drbg)
815 * length: drbg_blocklen(drbg)
817 * drbg_hash_process_addtl uses the scratchpad, but fully completes
818 * before either of the functions mentioned before are invoked. Therefore,
819 * drbg_hash_process_addtl does not need to be specifically considered.
822 /* Derivation Function for Hash DRBG as defined in 10.4.1 */
823 static int drbg_hash_df(struct drbg_state
*drbg
,
824 unsigned char *outval
, size_t outlen
,
825 struct list_head
*entropylist
)
829 unsigned char input
[5];
830 unsigned char *tmp
= drbg
->scratchpad
+ drbg_statelen(drbg
);
831 struct drbg_string data
;
835 drbg_cpu_to_be32((outlen
* 8), &input
[1]);
837 /* 10.4.1 step 4.1 -- concatenation of data for input into hash */
838 drbg_string_fill(&data
, input
, 5);
839 list_add(&data
.list
, entropylist
);
842 while (len
< outlen
) {
844 /* 10.4.1 step 4.1 */
845 ret
= drbg_kcapi_hash(drbg
, NULL
, tmp
, entropylist
);
848 /* 10.4.1 step 4.2 */
850 blocklen
= (drbg_blocklen(drbg
) < (outlen
- len
)) ?
851 drbg_blocklen(drbg
) : (outlen
- len
);
852 memcpy(outval
+ len
, tmp
, blocklen
);
857 memset(tmp
, 0, drbg_blocklen(drbg
));
861 /* update function for Hash DRBG as defined in 10.1.1.2 / 10.1.1.3 */
862 static int drbg_hash_update(struct drbg_state
*drbg
, struct list_head
*seed
,
866 struct drbg_string data1
, data2
;
868 LIST_HEAD(datalist2
);
869 unsigned char *V
= drbg
->scratchpad
;
870 unsigned char prefix
= DRBG_PREFIX1
;
876 /* 10.1.1.3 step 1 */
877 memcpy(V
, drbg
->V
, drbg_statelen(drbg
));
878 drbg_string_fill(&data1
, &prefix
, 1);
879 list_add_tail(&data1
.list
, &datalist
);
880 drbg_string_fill(&data2
, V
, drbg_statelen(drbg
));
881 list_add_tail(&data2
.list
, &datalist
);
883 list_splice_tail(seed
, &datalist
);
885 /* 10.1.1.2 / 10.1.1.3 step 2 and 3 */
886 ret
= drbg_hash_df(drbg
, drbg
->V
, drbg_statelen(drbg
), &datalist
);
890 /* 10.1.1.2 / 10.1.1.3 step 4 */
891 prefix
= DRBG_PREFIX0
;
892 drbg_string_fill(&data1
, &prefix
, 1);
893 list_add_tail(&data1
.list
, &datalist2
);
894 drbg_string_fill(&data2
, drbg
->V
, drbg_statelen(drbg
));
895 list_add_tail(&data2
.list
, &datalist2
);
896 /* 10.1.1.2 / 10.1.1.3 step 4 */
897 ret
= drbg_hash_df(drbg
, drbg
->C
, drbg_statelen(drbg
), &datalist2
);
900 memset(drbg
->scratchpad
, 0, drbg_statelen(drbg
));
904 /* processing of additional information string for Hash DRBG */
905 static int drbg_hash_process_addtl(struct drbg_state
*drbg
,
906 struct list_head
*addtl
)
909 struct drbg_string data1
, data2
;
911 unsigned char prefix
= DRBG_PREFIX2
;
913 /* 10.1.1.4 step 2 */
914 if (!addtl
|| list_empty(addtl
))
917 /* 10.1.1.4 step 2a */
918 drbg_string_fill(&data1
, &prefix
, 1);
919 drbg_string_fill(&data2
, drbg
->V
, drbg_statelen(drbg
));
920 list_add_tail(&data1
.list
, &datalist
);
921 list_add_tail(&data2
.list
, &datalist
);
922 list_splice_tail(addtl
, &datalist
);
923 ret
= drbg_kcapi_hash(drbg
, NULL
, drbg
->scratchpad
, &datalist
);
927 /* 10.1.1.4 step 2b */
928 drbg_add_buf(drbg
->V
, drbg_statelen(drbg
),
929 drbg
->scratchpad
, drbg_blocklen(drbg
));
932 memset(drbg
->scratchpad
, 0, drbg_blocklen(drbg
));
936 /* Hashgen defined in 10.1.1.4 */
937 static int drbg_hash_hashgen(struct drbg_state
*drbg
,
943 unsigned char *src
= drbg
->scratchpad
;
944 unsigned char *dst
= drbg
->scratchpad
+ drbg_statelen(drbg
);
945 struct drbg_string data
;
948 /* 10.1.1.4 step hashgen 2 */
949 memcpy(src
, drbg
->V
, drbg_statelen(drbg
));
951 drbg_string_fill(&data
, src
, drbg_statelen(drbg
));
952 list_add_tail(&data
.list
, &datalist
);
953 while (len
< buflen
) {
954 unsigned int outlen
= 0;
955 /* 10.1.1.4 step hashgen 4.1 */
956 ret
= drbg_kcapi_hash(drbg
, NULL
, dst
, &datalist
);
961 outlen
= (drbg_blocklen(drbg
) < (buflen
- len
)) ?
962 drbg_blocklen(drbg
) : (buflen
- len
);
963 if (!drbg_fips_continuous_test(drbg
, dst
)) {
964 crypto_inc(src
, drbg_statelen(drbg
));
967 /* 10.1.1.4 step hashgen 4.2 */
968 memcpy(buf
+ len
, dst
, outlen
);
970 /* 10.1.1.4 hashgen step 4.3 */
972 crypto_inc(src
, drbg_statelen(drbg
));
976 memset(drbg
->scratchpad
, 0,
977 (drbg_statelen(drbg
) + drbg_blocklen(drbg
)));
981 /* generate function for Hash DRBG as defined in 10.1.1.4 */
982 static int drbg_hash_generate(struct drbg_state
*drbg
,
983 unsigned char *buf
, unsigned int buflen
,
984 struct list_head
*addtl
)
989 unsigned char req
[8];
992 unsigned char prefix
= DRBG_PREFIX3
;
993 struct drbg_string data1
, data2
;
996 /* 10.1.1.4 step 2 */
997 ret
= drbg_hash_process_addtl(drbg
, addtl
);
1000 /* 10.1.1.4 step 3 */
1001 len
= drbg_hash_hashgen(drbg
, buf
, buflen
);
1003 /* this is the value H as documented in 10.1.1.4 */
1004 /* 10.1.1.4 step 4 */
1005 drbg_string_fill(&data1
, &prefix
, 1);
1006 list_add_tail(&data1
.list
, &datalist
);
1007 drbg_string_fill(&data2
, drbg
->V
, drbg_statelen(drbg
));
1008 list_add_tail(&data2
.list
, &datalist
);
1009 ret
= drbg_kcapi_hash(drbg
, NULL
, drbg
->scratchpad
, &datalist
);
1015 /* 10.1.1.4 step 5 */
1016 drbg_add_buf(drbg
->V
, drbg_statelen(drbg
),
1017 drbg
->scratchpad
, drbg_blocklen(drbg
));
1018 drbg_add_buf(drbg
->V
, drbg_statelen(drbg
),
1019 drbg
->C
, drbg_statelen(drbg
));
1020 u
.req_int
= cpu_to_be64(drbg
->reseed_ctr
);
1021 drbg_add_buf(drbg
->V
, drbg_statelen(drbg
), u
.req
, 8);
1024 memset(drbg
->scratchpad
, 0, drbg_blocklen(drbg
));
1029 * scratchpad usage: as update and generate are used isolated, both
1030 * can use the scratchpad
1032 static struct drbg_state_ops drbg_hash_ops
= {
1033 .update
= drbg_hash_update
,
1034 .generate
= drbg_hash_generate
,
1035 .crypto_init
= drbg_init_hash_kernel
,
1036 .crypto_fini
= drbg_fini_hash_kernel
,
1038 #endif /* CONFIG_CRYPTO_DRBG_HASH */
1040 /******************************************************************
1041 * Functions common for DRBG implementations
1042 ******************************************************************/
1045 * Seeding or reseeding of the DRBG
1047 * @drbg: DRBG state struct
1048 * @pers: personalization / additional information buffer
1049 * @reseed: 0 for initial seed process, 1 for reseeding
1053 * error value otherwise
1055 static int drbg_seed(struct drbg_state
*drbg
, struct drbg_string
*pers
,
1059 unsigned char *entropy
= NULL
;
1060 size_t entropylen
= 0;
1061 struct drbg_string data1
;
1062 LIST_HEAD(seedlist
);
1064 /* 9.1 / 9.2 / 9.3.1 step 3 */
1065 if (pers
&& pers
->len
> (drbg_max_addtl(drbg
))) {
1066 pr_devel("DRBG: personalization string too long %zu\n",
1071 if (drbg
->test_data
&& drbg
->test_data
->testentropy
) {
1072 drbg_string_fill(&data1
, drbg
->test_data
->testentropy
->buf
,
1073 drbg
->test_data
->testentropy
->len
);
1074 pr_devel("DRBG: using test entropy\n");
1077 * Gather entropy equal to the security strength of the DRBG.
1078 * With a derivation function, a nonce is required in addition
1079 * to the entropy. A nonce must be at least 1/2 of the security
1080 * strength of the DRBG in size. Thus, entropy * nonce is 3/2
1081 * of the strength. The consideration of a nonce is only
1082 * applicable during initial seeding.
1084 entropylen
= drbg_sec_strength(drbg
->core
->flags
);
1088 entropylen
= ((entropylen
+ 1) / 2) * 3;
1089 pr_devel("DRBG: (re)seeding with %zu bytes of entropy\n",
1091 entropy
= kzalloc(entropylen
, GFP_KERNEL
);
1094 get_random_bytes(entropy
, entropylen
);
1095 drbg_string_fill(&data1
, entropy
, entropylen
);
1097 list_add_tail(&data1
.list
, &seedlist
);
1100 * concatenation of entropy with personalization str / addtl input)
1101 * the variable pers is directly handed in by the caller, so check its
1102 * contents whether it is appropriate
1104 if (pers
&& pers
->buf
&& 0 < pers
->len
) {
1105 list_add_tail(&pers
->list
, &seedlist
);
1106 pr_devel("DRBG: using personalization string\n");
1110 memset(drbg
->V
, 0, drbg_statelen(drbg
));
1111 memset(drbg
->C
, 0, drbg_statelen(drbg
));
1114 ret
= drbg
->d_ops
->update(drbg
, &seedlist
, reseed
);
1118 drbg
->seeded
= true;
1119 /* 10.1.1.2 / 10.1.1.3 step 5 */
1120 drbg
->reseed_ctr
= 1;
1127 /* Free all substructures in a DRBG state without the DRBG state structure */
1128 static inline void drbg_dealloc_state(struct drbg_state
*drbg
)
1136 kzfree(drbg
->scratchpad
);
1137 drbg
->scratchpad
= NULL
;
1138 drbg
->reseed_ctr
= 0;
1141 #ifdef CONFIG_CRYPTO_FIPS
1144 drbg
->fips_primed
= false;
1149 * Allocate all sub-structures for a DRBG state.
1150 * The DRBG state structure must already be allocated.
1152 static inline int drbg_alloc_state(struct drbg_state
*drbg
)
1155 unsigned int sb_size
= 0;
1157 switch (drbg
->core
->flags
& DRBG_TYPE_MASK
) {
1158 #ifdef CONFIG_CRYPTO_DRBG_HMAC
1160 drbg
->d_ops
= &drbg_hmac_ops
;
1162 #endif /* CONFIG_CRYPTO_DRBG_HMAC */
1163 #ifdef CONFIG_CRYPTO_DRBG_HASH
1165 drbg
->d_ops
= &drbg_hash_ops
;
1167 #endif /* CONFIG_CRYPTO_DRBG_HASH */
1168 #ifdef CONFIG_CRYPTO_DRBG_CTR
1170 drbg
->d_ops
= &drbg_ctr_ops
;
1172 #endif /* CONFIG_CRYPTO_DRBG_CTR */
1178 drbg
->V
= kmalloc(drbg_statelen(drbg
), GFP_KERNEL
);
1181 drbg
->C
= kmalloc(drbg_statelen(drbg
), GFP_KERNEL
);
1184 #ifdef CONFIG_CRYPTO_FIPS
1185 drbg
->prev
= kmalloc(drbg_blocklen(drbg
), GFP_KERNEL
);
1188 drbg
->fips_primed
= false;
1190 /* scratchpad is only generated for CTR and Hash */
1191 if (drbg
->core
->flags
& DRBG_HMAC
)
1193 else if (drbg
->core
->flags
& DRBG_CTR
)
1194 sb_size
= drbg_statelen(drbg
) + drbg_blocklen(drbg
) + /* temp */
1195 drbg_statelen(drbg
) + /* df_data */
1196 drbg_blocklen(drbg
) + /* pad */
1197 drbg_blocklen(drbg
) + /* iv */
1198 drbg_statelen(drbg
) + drbg_blocklen(drbg
); /* temp */
1200 sb_size
= drbg_statelen(drbg
) + drbg_blocklen(drbg
);
1203 drbg
->scratchpad
= kzalloc(sb_size
, GFP_KERNEL
);
1204 if (!drbg
->scratchpad
)
1210 drbg_dealloc_state(drbg
);
1214 /*************************************************************************
1215 * DRBG interface functions
1216 *************************************************************************/
1219 * DRBG generate function as required by SP800-90A - this function
1220 * generates random numbers
1222 * @drbg DRBG state handle
1223 * @buf Buffer where to store the random numbers -- the buffer must already
1224 * be pre-allocated by caller
1225 * @buflen Length of output buffer - this value defines the number of random
1226 * bytes pulled from DRBG
1227 * @addtl Additional input that is mixed into state, may be NULL -- note
1228 * the entropy is pulled by the DRBG internally unconditionally
1229 * as defined in SP800-90A. The additional input is mixed into
1230 * the state in addition to the pulled entropy.
1232 * return: 0 when all bytes are generated; < 0 in case of an error
1234 static int drbg_generate(struct drbg_state
*drbg
,
1235 unsigned char *buf
, unsigned int buflen
,
1236 struct drbg_string
*addtl
)
1239 LIST_HEAD(addtllist
);
1242 pr_devel("DRBG: not yet seeded\n");
1245 if (0 == buflen
|| !buf
) {
1246 pr_devel("DRBG: no output buffer provided\n");
1249 if (addtl
&& NULL
== addtl
->buf
&& 0 < addtl
->len
) {
1250 pr_devel("DRBG: wrong format of additional information\n");
1256 if (buflen
> (drbg_max_request_bytes(drbg
))) {
1257 pr_devel("DRBG: requested random numbers too large %u\n",
1262 /* 9.3.1 step 3 is implicit with the chosen DRBG */
1265 if (addtl
&& addtl
->len
> (drbg_max_addtl(drbg
))) {
1266 pr_devel("DRBG: additional information string too long %zu\n",
1270 /* 9.3.1 step 5 is implicit with the chosen DRBG */
1273 * 9.3.1 step 6 and 9 supplemented by 9.3.2 step c is implemented
1274 * here. The spec is a bit convoluted here, we make it simpler.
1276 if ((drbg_max_requests(drbg
)) < drbg
->reseed_ctr
)
1277 drbg
->seeded
= false;
1279 if (drbg
->pr
|| !drbg
->seeded
) {
1280 pr_devel("DRBG: reseeding before generation (prediction "
1281 "resistance: %s, state %s)\n",
1282 drbg
->pr
? "true" : "false",
1283 drbg
->seeded
? "seeded" : "unseeded");
1284 /* 9.3.1 steps 7.1 through 7.3 */
1285 len
= drbg_seed(drbg
, addtl
, true);
1288 /* 9.3.1 step 7.4 */
1292 if (addtl
&& 0 < addtl
->len
)
1293 list_add_tail(&addtl
->list
, &addtllist
);
1294 /* 9.3.1 step 8 and 10 */
1295 len
= drbg
->d_ops
->generate(drbg
, buf
, buflen
, &addtllist
);
1297 /* 10.1.1.4 step 6, 10.1.2.5 step 7, 10.2.1.5.2 step 7 */
1303 * Section 11.3.3 requires to re-perform self tests after some
1304 * generated random numbers. The chosen value after which self
1305 * test is performed is arbitrary, but it should be reasonable.
1306 * However, we do not perform the self tests because of the following
1307 * reasons: it is mathematically impossible that the initial self tests
1308 * were successfully and the following are not. If the initial would
1309 * pass and the following would not, the kernel integrity is violated.
1310 * In this case, the entire kernel operation is questionable and it
1311 * is unlikely that the integrity violation only affects the
1312 * correct operation of the DRBG.
1314 * Albeit the following code is commented out, it is provided in
1315 * case somebody has a need to implement the test of 11.3.3.
1318 if (drbg
->reseed_ctr
&& !(drbg
->reseed_ctr
% 4096)) {
1320 pr_devel("DRBG: start to perform self test\n");
1321 if (drbg
->core
->flags
& DRBG_HMAC
)
1322 err
= alg_test("drbg_pr_hmac_sha256",
1323 "drbg_pr_hmac_sha256", 0, 0);
1324 else if (drbg
->core
->flags
& DRBG_CTR
)
1325 err
= alg_test("drbg_pr_ctr_aes128",
1326 "drbg_pr_ctr_aes128", 0, 0);
1328 err
= alg_test("drbg_pr_sha256",
1329 "drbg_pr_sha256", 0, 0);
1331 pr_err("DRBG: periodical self test failed\n");
1333 * uninstantiate implies that from now on, only errors
1334 * are returned when reusing this DRBG cipher handle
1336 drbg_uninstantiate(drbg
);
1339 pr_devel("DRBG: self test successful\n");
1345 * All operations were successful, return 0 as mandated by
1346 * the kernel crypto API interface.
1354 * Wrapper around drbg_generate which can pull arbitrary long strings
1355 * from the DRBG without hitting the maximum request limitation.
1357 * Parameters: see drbg_generate
1358 * Return codes: see drbg_generate -- if one drbg_generate request fails,
1359 * the entire drbg_generate_long request fails
1361 static int drbg_generate_long(struct drbg_state
*drbg
,
1362 unsigned char *buf
, unsigned int buflen
,
1363 struct drbg_string
*addtl
)
1365 unsigned int len
= 0;
1366 unsigned int slice
= 0;
1369 unsigned int chunk
= 0;
1370 slice
= ((buflen
- len
) / drbg_max_request_bytes(drbg
));
1371 chunk
= slice
? drbg_max_request_bytes(drbg
) : (buflen
- len
);
1372 mutex_lock(&drbg
->drbg_mutex
);
1373 err
= drbg_generate(drbg
, buf
+ len
, chunk
, addtl
);
1374 mutex_unlock(&drbg
->drbg_mutex
);
1378 } while (slice
> 0 && (len
< buflen
));
1383 * DRBG instantiation function as required by SP800-90A - this function
1384 * sets up the DRBG handle, performs the initial seeding and all sanity
1385 * checks required by SP800-90A
1387 * @drbg memory of state -- if NULL, new memory is allocated
1388 * @pers Personalization string that is mixed into state, may be NULL -- note
1389 * the entropy is pulled by the DRBG internally unconditionally
1390 * as defined in SP800-90A. The additional input is mixed into
1391 * the state in addition to the pulled entropy.
1392 * @coreref reference to core
1393 * @pr prediction resistance enabled
1397 * error value otherwise
1399 static int drbg_instantiate(struct drbg_state
*drbg
, struct drbg_string
*pers
,
1400 int coreref
, bool pr
)
1405 pr_devel("DRBG: Initializing DRBG core %d with prediction resistance "
1406 "%s\n", coreref
, pr
? "enabled" : "disabled");
1407 mutex_lock(&drbg
->drbg_mutex
);
1409 /* 9.1 step 1 is implicit with the selected DRBG type */
1412 * 9.1 step 2 is implicit as caller can select prediction resistance
1413 * and the flag is copied into drbg->flags --
1414 * all DRBG types support prediction resistance
1417 /* 9.1 step 4 is implicit in drbg_sec_strength */
1420 drbg
->core
= &drbg_cores
[coreref
];
1422 drbg
->seeded
= false;
1424 ret
= drbg_alloc_state(drbg
);
1429 if (drbg
->d_ops
->crypto_init(drbg
))
1435 ret
= drbg_seed(drbg
, pers
, reseed
);
1437 if (ret
&& !reseed
) {
1438 drbg
->d_ops
->crypto_fini(drbg
);
1442 mutex_unlock(&drbg
->drbg_mutex
);
1446 drbg_dealloc_state(drbg
);
1448 mutex_unlock(&drbg
->drbg_mutex
);
1453 * DRBG uninstantiate function as required by SP800-90A - this function
1454 * frees all buffers and the DRBG handle
1456 * @drbg DRBG state handle
1461 static int drbg_uninstantiate(struct drbg_state
*drbg
)
1464 drbg
->d_ops
->crypto_fini(drbg
);
1465 drbg_dealloc_state(drbg
);
1466 /* no scrubbing of test_data -- this shall survive an uninstantiate */
1471 * Helper function for setting the test data in the DRBG
1473 * @drbg DRBG state handle
1474 * @test_data test data to sets
1476 static inline void drbg_set_testdata(struct drbg_state
*drbg
,
1477 struct drbg_test_data
*test_data
)
1479 if (!test_data
|| !test_data
->testentropy
)
1481 mutex_lock(&drbg
->drbg_mutex
);;
1482 drbg
->test_data
= test_data
;
1483 mutex_unlock(&drbg
->drbg_mutex
);
1486 /***************************************************************
1487 * Kernel crypto API cipher invocations requested by DRBG
1488 ***************************************************************/
1490 #if defined(CONFIG_CRYPTO_DRBG_HASH) || defined(CONFIG_CRYPTO_DRBG_HMAC)
1492 struct shash_desc shash
;
1496 static int drbg_init_hash_kernel(struct drbg_state
*drbg
)
1498 struct sdesc
*sdesc
;
1499 struct crypto_shash
*tfm
;
1501 tfm
= crypto_alloc_shash(drbg
->core
->backend_cra_name
, 0, 0);
1503 pr_info("DRBG: could not allocate digest TFM handle\n");
1504 return PTR_ERR(tfm
);
1506 BUG_ON(drbg_blocklen(drbg
) != crypto_shash_digestsize(tfm
));
1507 sdesc
= kzalloc(sizeof(struct shash_desc
) + crypto_shash_descsize(tfm
),
1510 crypto_free_shash(tfm
);
1514 sdesc
->shash
.tfm
= tfm
;
1515 sdesc
->shash
.flags
= 0;
1516 drbg
->priv_data
= sdesc
;
1520 static int drbg_fini_hash_kernel(struct drbg_state
*drbg
)
1522 struct sdesc
*sdesc
= (struct sdesc
*)drbg
->priv_data
;
1524 crypto_free_shash(sdesc
->shash
.tfm
);
1527 drbg
->priv_data
= NULL
;
1531 static int drbg_kcapi_hash(struct drbg_state
*drbg
, const unsigned char *key
,
1532 unsigned char *outval
, const struct list_head
*in
)
1534 struct sdesc
*sdesc
= (struct sdesc
*)drbg
->priv_data
;
1535 struct drbg_string
*input
= NULL
;
1538 crypto_shash_setkey(sdesc
->shash
.tfm
, key
, drbg_statelen(drbg
));
1539 crypto_shash_init(&sdesc
->shash
);
1540 list_for_each_entry(input
, in
, list
)
1541 crypto_shash_update(&sdesc
->shash
, input
->buf
, input
->len
);
1542 return crypto_shash_final(&sdesc
->shash
, outval
);
1544 #endif /* (CONFIG_CRYPTO_DRBG_HASH || CONFIG_CRYPTO_DRBG_HMAC) */
1546 #ifdef CONFIG_CRYPTO_DRBG_CTR
1547 static int drbg_init_sym_kernel(struct drbg_state
*drbg
)
1550 struct crypto_cipher
*tfm
;
1552 tfm
= crypto_alloc_cipher(drbg
->core
->backend_cra_name
, 0, 0);
1554 pr_info("DRBG: could not allocate cipher TFM handle\n");
1555 return PTR_ERR(tfm
);
1557 BUG_ON(drbg_blocklen(drbg
) != crypto_cipher_blocksize(tfm
));
1558 drbg
->priv_data
= tfm
;
1562 static int drbg_fini_sym_kernel(struct drbg_state
*drbg
)
1564 struct crypto_cipher
*tfm
=
1565 (struct crypto_cipher
*)drbg
->priv_data
;
1567 crypto_free_cipher(tfm
);
1568 drbg
->priv_data
= NULL
;
1572 static int drbg_kcapi_sym(struct drbg_state
*drbg
, const unsigned char *key
,
1573 unsigned char *outval
, const struct drbg_string
*in
)
1575 struct crypto_cipher
*tfm
=
1576 (struct crypto_cipher
*)drbg
->priv_data
;
1578 crypto_cipher_setkey(tfm
, key
, (drbg_keylen(drbg
)));
1579 /* there is only component in *in */
1580 BUG_ON(in
->len
< drbg_blocklen(drbg
));
1581 crypto_cipher_encrypt_one(tfm
, outval
, in
->buf
);
1584 #endif /* CONFIG_CRYPTO_DRBG_CTR */
1586 /***************************************************************
1587 * Kernel crypto API interface to register DRBG
1588 ***************************************************************/
1591 * Look up the DRBG flags by given kernel crypto API cra_name
1592 * The code uses the drbg_cores definition to do this
1594 * @cra_name kernel crypto API cra_name
1595 * @coreref reference to integer which is filled with the pointer to
1596 * the applicable core
1597 * @pr reference for setting prediction resistance
1601 static inline void drbg_convert_tfm_core(const char *cra_driver_name
,
1602 int *coreref
, bool *pr
)
1609 /* disassemble the names */
1610 if (!memcmp(cra_driver_name
, "drbg_nopr_", 10)) {
1613 } else if (!memcmp(cra_driver_name
, "drbg_pr_", 8)) {
1619 /* remove the first part */
1620 len
= strlen(cra_driver_name
) - start
;
1621 for (i
= 0; ARRAY_SIZE(drbg_cores
) > i
; i
++) {
1622 if (!memcmp(cra_driver_name
+ start
, drbg_cores
[i
].cra_name
,
1630 static int drbg_kcapi_init(struct crypto_tfm
*tfm
)
1632 struct drbg_state
*drbg
= crypto_tfm_ctx(tfm
);
1634 mutex_init(&drbg
->drbg_mutex
);
1639 static void drbg_kcapi_cleanup(struct crypto_tfm
*tfm
)
1641 drbg_uninstantiate(crypto_tfm_ctx(tfm
));
1645 * Generate random numbers invoked by the kernel crypto API:
1646 * The API of the kernel crypto API is extended as follows:
1648 * If dlen is larger than zero, rdata is interpreted as the output buffer
1649 * where random data is to be stored.
1651 * If dlen is zero, rdata is interpreted as a pointer to a struct drbg_gen
1652 * which holds the additional information string that is used for the
1653 * DRBG generation process. The output buffer that is to be used to store
1654 * data is also pointed to by struct drbg_gen.
1656 static int drbg_kcapi_random(struct crypto_rng
*tfm
, u8
*rdata
,
1659 struct drbg_state
*drbg
= crypto_rng_ctx(tfm
);
1661 return drbg_generate_long(drbg
, rdata
, dlen
, NULL
);
1663 struct drbg_gen
*data
= (struct drbg_gen
*)rdata
;
1664 struct drbg_string addtl
;
1665 /* catch NULL pointer */
1668 drbg_set_testdata(drbg
, data
->test_data
);
1669 /* linked list variable is now local to allow modification */
1670 drbg_string_fill(&addtl
, data
->addtl
->buf
, data
->addtl
->len
);
1671 return drbg_generate_long(drbg
, data
->outbuf
, data
->outlen
,
1677 * Seed the DRBG invoked by the kernel crypto API
1678 * Similar to the generate function of drbg_kcapi_random, this
1679 * function extends the kernel crypto API interface with struct drbg_gen
1681 static int drbg_kcapi_reset(struct crypto_rng
*tfm
, u8
*seed
, unsigned int slen
)
1683 struct drbg_state
*drbg
= crypto_rng_ctx(tfm
);
1684 struct crypto_tfm
*tfm_base
= crypto_rng_tfm(tfm
);
1686 struct drbg_string seed_string
;
1689 drbg_convert_tfm_core(crypto_tfm_alg_driver_name(tfm_base
), &coreref
,
1692 drbg_string_fill(&seed_string
, seed
, slen
);
1693 return drbg_instantiate(drbg
, &seed_string
, coreref
, pr
);
1695 struct drbg_gen
*data
= (struct drbg_gen
*)seed
;
1696 /* allow invocation of API call with NULL, 0 */
1698 return drbg_instantiate(drbg
, NULL
, coreref
, pr
);
1699 drbg_set_testdata(drbg
, data
->test_data
);
1700 /* linked list variable is now local to allow modification */
1701 drbg_string_fill(&seed_string
, data
->addtl
->buf
,
1703 return drbg_instantiate(drbg
, &seed_string
, coreref
, pr
);
1707 /***************************************************************
1708 * Kernel module: code to load the module
1709 ***************************************************************/
1712 * Tests as defined in 11.3.2 in addition to the cipher tests: testing
1713 * of the error handling.
1715 * Note: testing of failing seed source as defined in 11.3.2 is not applicable
1716 * as seed source of get_random_bytes does not fail.
1718 * Note 2: There is no sensible way of testing the reseed counter
1719 * enforcement, so skip it.
1721 static inline int __init
drbg_healthcheck_sanity(void)
1723 #ifdef CONFIG_CRYPTO_FIPS
1725 #define OUTBUFLEN 16
1726 unsigned char buf
[OUTBUFLEN
];
1727 struct drbg_state
*drbg
= NULL
;
1732 struct drbg_string addtl
;
1733 size_t max_addtllen
, max_request_bytes
;
1735 /* only perform test in FIPS mode */
1739 #ifdef CONFIG_CRYPTO_DRBG_CTR
1740 drbg_convert_tfm_core("drbg_nopr_ctr_aes128", &coreref
, &pr
);
1741 #elif defined CONFIG_CRYPTO_DRBG_HASH
1742 drbg_convert_tfm_core("drbg_nopr_sha256", &coreref
, &pr
);
1744 drbg_convert_tfm_core("drbg_nopr_hmac_sha256", &coreref
, &pr
);
1747 drbg
= kzalloc(sizeof(struct drbg_state
), GFP_KERNEL
);
1751 mutex_init(&drbg
->drbg_mutex
);
1754 * if the following tests fail, it is likely that there is a buffer
1755 * overflow as buf is much smaller than the requested or provided
1756 * string lengths -- in case the error handling does not succeed
1757 * we may get an OOPS. And we want to get an OOPS as this is a
1761 /* get a valid instance of DRBG for following tests */
1762 ret
= drbg_instantiate(drbg
, NULL
, coreref
, pr
);
1767 max_addtllen
= drbg_max_addtl(drbg
);
1768 max_request_bytes
= drbg_max_request_bytes(drbg
);
1769 drbg_string_fill(&addtl
, buf
, max_addtllen
+ 1);
1770 /* overflow addtllen with additonal info string */
1771 len
= drbg_generate(drbg
, buf
, OUTBUFLEN
, &addtl
);
1773 /* overflow max_bits */
1774 len
= drbg_generate(drbg
, buf
, (max_request_bytes
+ 1), NULL
);
1776 drbg_uninstantiate(drbg
);
1778 /* overflow max addtllen with personalization string */
1779 ret
= drbg_instantiate(drbg
, &addtl
, coreref
, pr
);
1781 /* all tests passed */
1784 pr_devel("DRBG: Sanity tests for failure code paths successfully "
1787 drbg_uninstantiate(drbg
);
1791 #else /* CONFIG_CRYPTO_FIPS */
1793 #endif /* CONFIG_CRYPTO_FIPS */
1796 static struct crypto_alg drbg_algs
[22];
1799 * Fill the array drbg_algs used to register the different DRBGs
1800 * with the kernel crypto API. To fill the array, the information
1801 * from drbg_cores[] is used.
1803 static inline void __init
drbg_fill_array(struct crypto_alg
*alg
,
1804 const struct drbg_core
*core
, int pr
)
1807 static int priority
= 100;
1809 memset(alg
, 0, sizeof(struct crypto_alg
));
1810 memcpy(alg
->cra_name
, "stdrng", 6);
1812 memcpy(alg
->cra_driver_name
, "drbg_pr_", 8);
1815 memcpy(alg
->cra_driver_name
, "drbg_nopr_", 10);
1818 memcpy(alg
->cra_driver_name
+ pos
, core
->cra_name
,
1819 strlen(core
->cra_name
));
1821 alg
->cra_priority
= priority
;
1824 * If FIPS mode enabled, the selected DRBG shall have the
1825 * highest cra_priority over other stdrng instances to ensure
1829 alg
->cra_priority
+= 200;
1831 alg
->cra_flags
= CRYPTO_ALG_TYPE_RNG
;
1832 alg
->cra_ctxsize
= sizeof(struct drbg_state
);
1833 alg
->cra_type
= &crypto_rng_type
;
1834 alg
->cra_module
= THIS_MODULE
;
1835 alg
->cra_init
= drbg_kcapi_init
;
1836 alg
->cra_exit
= drbg_kcapi_cleanup
;
1837 alg
->cra_u
.rng
.rng_make_random
= drbg_kcapi_random
;
1838 alg
->cra_u
.rng
.rng_reset
= drbg_kcapi_reset
;
1839 alg
->cra_u
.rng
.seedsize
= 0;
1842 static int __init
drbg_init(void)
1844 unsigned int i
= 0; /* pointer to drbg_algs */
1845 unsigned int j
= 0; /* pointer to drbg_cores */
1848 ret
= drbg_healthcheck_sanity();
1852 if (ARRAY_SIZE(drbg_cores
) * 2 > ARRAY_SIZE(drbg_algs
)) {
1853 pr_info("DRBG: Cannot register all DRBG types"
1854 "(slots needed: %zu, slots available: %zu)\n",
1855 ARRAY_SIZE(drbg_cores
) * 2, ARRAY_SIZE(drbg_algs
));
1860 * each DRBG definition can be used with PR and without PR, thus
1861 * we instantiate each DRBG in drbg_cores[] twice.
1863 * As the order of placing them into the drbg_algs array matters
1864 * (the later DRBGs receive a higher cra_priority) we register the
1865 * prediction resistance DRBGs first as the should not be too
1868 for (j
= 0; ARRAY_SIZE(drbg_cores
) > j
; j
++, i
++)
1869 drbg_fill_array(&drbg_algs
[i
], &drbg_cores
[j
], 1);
1870 for (j
= 0; ARRAY_SIZE(drbg_cores
) > j
; j
++, i
++)
1871 drbg_fill_array(&drbg_algs
[i
], &drbg_cores
[j
], 0);
1872 return crypto_register_algs(drbg_algs
, (ARRAY_SIZE(drbg_cores
) * 2));
1875 static void __exit
drbg_exit(void)
1877 crypto_unregister_algs(drbg_algs
, (ARRAY_SIZE(drbg_cores
) * 2));
1880 module_init(drbg_init
);
1881 module_exit(drbg_exit
);
1882 #ifndef CRYPTO_DRBG_HASH_STRING
1883 #define CRYPTO_DRBG_HASH_STRING ""
1885 #ifndef CRYPTO_DRBG_HMAC_STRING
1886 #define CRYPTO_DRBG_HMAC_STRING ""
1888 #ifndef CRYPTO_DRBG_CTR_STRING
1889 #define CRYPTO_DRBG_CTR_STRING ""
1891 MODULE_LICENSE("GPL");
1892 MODULE_AUTHOR("Stephan Mueller <smueller@chronox.de>");
1893 MODULE_DESCRIPTION("NIST SP800-90A Deterministic Random Bit Generator (DRBG) "
1894 "using following cores: "
1895 CRYPTO_DRBG_HASH_STRING
1896 CRYPTO_DRBG_HMAC_STRING
1897 CRYPTO_DRBG_CTR_STRING
);