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
= "ecb(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
= "ecb(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
= "ecb(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
225 * The FIPS test can be called in an endless loop until it returns
226 * true. Although the code looks like a potential for a deadlock, it
227 * is not the case, because returning a false cannot mathematically
228 * occur (except once when a reseed took place and the updated state
229 * would is now set up such that the generation of new value returns
230 * an identical one -- this is most unlikely and would happen only once).
231 * Thus, if this function repeatedly returns false and thus would cause
232 * a deadlock, the integrity of the entire kernel is lost.
235 * @buf output buffer of random data to be checked
241 static bool drbg_fips_continuous_test(struct drbg_state
*drbg
,
242 const unsigned char *buf
)
244 #ifdef CONFIG_CRYPTO_FIPS
246 /* skip test if we test the overall system */
249 /* only perform test in FIPS mode */
250 if (0 == fips_enabled
)
252 if (!drbg
->fips_primed
) {
253 /* Priming of FIPS test */
254 memcpy(drbg
->prev
, buf
, drbg_blocklen(drbg
));
255 drbg
->fips_primed
= true;
256 /* return false due to priming, i.e. another round is needed */
259 ret
= memcmp(drbg
->prev
, buf
, drbg_blocklen(drbg
));
260 memcpy(drbg
->prev
, buf
, drbg_blocklen(drbg
));
261 /* the test shall pass when the two compared values are not equal */
265 #endif /* CONFIG_CRYPTO_FIPS */
269 * Convert an integer into a byte representation of this integer.
270 * The byte representation is big-endian
272 * @val value to be converted
273 * @buf buffer holding the converted integer -- caller must ensure that
274 * buffer size is at least 32 bit
276 #if (defined(CONFIG_CRYPTO_DRBG_HASH) || defined(CONFIG_CRYPTO_DRBG_CTR))
277 static inline void drbg_cpu_to_be32(__u32 val
, unsigned char *buf
)
282 struct s
*conversion
= (struct s
*) buf
;
284 conversion
->conv
= cpu_to_be32(val
);
286 #endif /* defined(CONFIG_CRYPTO_DRBG_HASH) || defined(CONFIG_CRYPTO_DRBG_CTR) */
288 /******************************************************************
289 * CTR DRBG callback functions
290 ******************************************************************/
292 #ifdef CONFIG_CRYPTO_DRBG_CTR
293 #define CRYPTO_DRBG_CTR_STRING "CTR "
294 MODULE_ALIAS_CRYPTO("drbg_pr_ctr_aes256");
295 MODULE_ALIAS_CRYPTO("drbg_nopr_ctr_aes256");
296 MODULE_ALIAS_CRYPTO("drbg_pr_ctr_aes192");
297 MODULE_ALIAS_CRYPTO("drbg_nopr_ctr_aes192");
298 MODULE_ALIAS_CRYPTO("drbg_pr_ctr_aes128");
299 MODULE_ALIAS_CRYPTO("drbg_nopr_ctr_aes128");
301 static int drbg_kcapi_sym(struct drbg_state
*drbg
, const unsigned char *key
,
302 unsigned char *outval
, const struct drbg_string
*in
);
303 static int drbg_init_sym_kernel(struct drbg_state
*drbg
);
304 static int drbg_fini_sym_kernel(struct drbg_state
*drbg
);
306 /* BCC function for CTR DRBG as defined in 10.4.3 */
307 static int drbg_ctr_bcc(struct drbg_state
*drbg
,
308 unsigned char *out
, const unsigned char *key
,
309 struct list_head
*in
)
312 struct drbg_string
*curr
= NULL
;
313 struct drbg_string data
;
316 drbg_string_fill(&data
, out
, drbg_blocklen(drbg
));
319 memset(out
, 0, drbg_blocklen(drbg
));
321 /* 10.4.3 step 2 / 4 */
322 list_for_each_entry(curr
, in
, list
) {
323 const unsigned char *pos
= curr
->buf
;
324 size_t len
= curr
->len
;
325 /* 10.4.3 step 4.1 */
327 /* 10.4.3 step 4.2 */
328 if (drbg_blocklen(drbg
) == cnt
) {
330 ret
= drbg_kcapi_sym(drbg
, key
, out
, &data
);
340 /* 10.4.3 step 4.2 for last block */
342 ret
= drbg_kcapi_sym(drbg
, key
, out
, &data
);
348 * scratchpad usage: drbg_ctr_update is interlinked with drbg_ctr_df
349 * (and drbg_ctr_bcc, but this function does not need any temporary buffers),
350 * the scratchpad is used as follows:
353 * start: drbg->scratchpad
354 * length: drbg_statelen(drbg) + drbg_blocklen(drbg)
355 * note: the cipher writing into this variable works
356 * blocklen-wise. Now, when the statelen is not a multiple
357 * of blocklen, the generateion loop below "spills over"
358 * by at most blocklen. Thus, we need to give sufficient
361 * start: drbg->scratchpad +
362 * drbg_statelen(drbg) + drbg_blocklen(drbg)
363 * length: drbg_statelen(drbg)
367 * start: df_data + drbg_statelen(drbg)
368 * length: drbg_blocklen(drbg)
370 * start: pad + drbg_blocklen(drbg)
371 * length: drbg_blocklen(drbg)
373 * start: iv + drbg_blocklen(drbg)
374 * length: drbg_satelen(drbg) + drbg_blocklen(drbg)
375 * note: temp is the buffer that the BCC function operates
376 * on. BCC operates blockwise. drbg_statelen(drbg)
377 * is sufficient when the DRBG state length is a multiple
378 * of the block size. For AES192 (and maybe other ciphers)
379 * this is not correct and the length for temp is
380 * insufficient (yes, that also means for such ciphers,
381 * the final output of all BCC rounds are truncated).
382 * Therefore, add drbg_blocklen(drbg) to cover all
386 /* Derivation Function for CTR DRBG as defined in 10.4.2 */
387 static int drbg_ctr_df(struct drbg_state
*drbg
,
388 unsigned char *df_data
, size_t bytes_to_return
,
389 struct list_head
*seedlist
)
392 unsigned char L_N
[8];
394 struct drbg_string S1
, S2
, S4
, cipherin
;
396 unsigned char *pad
= df_data
+ drbg_statelen(drbg
);
397 unsigned char *iv
= pad
+ drbg_blocklen(drbg
);
398 unsigned char *temp
= iv
+ drbg_blocklen(drbg
);
400 unsigned int templen
= 0;
404 const unsigned char *K
= (unsigned char *)
405 "\x00\x01\x02\x03\x04\x05\x06\x07"
406 "\x08\x09\x0a\x0b\x0c\x0d\x0e\x0f"
407 "\x10\x11\x12\x13\x14\x15\x16\x17"
408 "\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f";
410 size_t generated_len
= 0;
412 struct drbg_string
*seed
= NULL
;
414 memset(pad
, 0, drbg_blocklen(drbg
));
415 memset(iv
, 0, drbg_blocklen(drbg
));
416 memset(temp
, 0, drbg_statelen(drbg
));
418 /* 10.4.2 step 1 is implicit as we work byte-wise */
421 if ((512/8) < bytes_to_return
)
424 /* 10.4.2 step 2 -- calculate the entire length of all input data */
425 list_for_each_entry(seed
, seedlist
, list
)
426 inputlen
+= seed
->len
;
427 drbg_cpu_to_be32(inputlen
, &L_N
[0]);
430 drbg_cpu_to_be32(bytes_to_return
, &L_N
[4]);
432 /* 10.4.2 step 5: length is L_N, input_string, one byte, padding */
433 padlen
= (inputlen
+ sizeof(L_N
) + 1) % (drbg_blocklen(drbg
));
434 /* wrap the padlen appropriately */
436 padlen
= drbg_blocklen(drbg
) - padlen
;
438 * pad / padlen contains the 0x80 byte and the following zero bytes.
439 * As the calculated padlen value only covers the number of zero
440 * bytes, this value has to be incremented by one for the 0x80 byte.
445 /* 10.4.2 step 4 -- first fill the linked list and then order it */
446 drbg_string_fill(&S1
, iv
, drbg_blocklen(drbg
));
447 list_add_tail(&S1
.list
, &bcc_list
);
448 drbg_string_fill(&S2
, L_N
, sizeof(L_N
));
449 list_add_tail(&S2
.list
, &bcc_list
);
450 list_splice_tail(seedlist
, &bcc_list
);
451 drbg_string_fill(&S4
, pad
, padlen
);
452 list_add_tail(&S4
.list
, &bcc_list
);
455 while (templen
< (drbg_keylen(drbg
) + (drbg_blocklen(drbg
)))) {
457 * 10.4.2 step 9.1 - the padding is implicit as the buffer
458 * holds zeros after allocation -- even the increment of i
459 * is irrelevant as the increment remains within length of i
461 drbg_cpu_to_be32(i
, iv
);
462 /* 10.4.2 step 9.2 -- BCC and concatenation with temp */
463 ret
= drbg_ctr_bcc(drbg
, temp
+ templen
, K
, &bcc_list
);
466 /* 10.4.2 step 9.3 */
468 templen
+= drbg_blocklen(drbg
);
472 X
= temp
+ (drbg_keylen(drbg
));
473 drbg_string_fill(&cipherin
, X
, drbg_blocklen(drbg
));
475 /* 10.4.2 step 12: overwriting of outval is implemented in next step */
478 while (generated_len
< bytes_to_return
) {
481 * 10.4.2 step 13.1: the truncation of the key length is
482 * implicit as the key is only drbg_blocklen in size based on
483 * the implementation of the cipher function callback
485 ret
= drbg_kcapi_sym(drbg
, temp
, X
, &cipherin
);
488 blocklen
= (drbg_blocklen(drbg
) <
489 (bytes_to_return
- generated_len
)) ?
490 drbg_blocklen(drbg
) :
491 (bytes_to_return
- generated_len
);
492 /* 10.4.2 step 13.2 and 14 */
493 memcpy(df_data
+ generated_len
, X
, blocklen
);
494 generated_len
+= blocklen
;
500 memset(iv
, 0, drbg_blocklen(drbg
));
501 memset(temp
, 0, drbg_statelen(drbg
));
502 memset(pad
, 0, drbg_blocklen(drbg
));
507 * update function of CTR DRBG as defined in 10.2.1.2
509 * The reseed variable has an enhanced meaning compared to the update
510 * functions of the other DRBGs as follows:
511 * 0 => initial seed from initialization
512 * 1 => reseed via drbg_seed
513 * 2 => first invocation from drbg_ctr_update when addtl is present. In
514 * this case, the df_data scratchpad is not deleted so that it is
515 * available for another calls to prevent calling the DF function
517 * 3 => second invocation from drbg_ctr_update. When the update function
518 * was called with addtl, the df_data memory already contains the
519 * DFed addtl information and we do not need to call DF again.
521 static int drbg_ctr_update(struct drbg_state
*drbg
, struct list_head
*seed
,
525 /* 10.2.1.2 step 1 */
526 unsigned char *temp
= drbg
->scratchpad
;
527 unsigned char *df_data
= drbg
->scratchpad
+ drbg_statelen(drbg
) +
529 unsigned char *temp_p
, *df_data_p
; /* pointer to iterate over buffers */
530 unsigned int len
= 0;
531 struct drbg_string cipherin
;
533 memset(temp
, 0, drbg_statelen(drbg
) + drbg_blocklen(drbg
));
535 memset(df_data
, 0, drbg_statelen(drbg
));
537 /* 10.2.1.3.2 step 2 and 10.2.1.4.2 step 2 */
539 ret
= drbg_ctr_df(drbg
, df_data
, drbg_statelen(drbg
), seed
);
544 drbg_string_fill(&cipherin
, drbg
->V
, drbg_blocklen(drbg
));
546 * 10.2.1.3.2 steps 2 and 3 are already covered as the allocation
547 * zeroizes all memory during initialization
549 while (len
< (drbg_statelen(drbg
))) {
550 /* 10.2.1.2 step 2.1 */
551 crypto_inc(drbg
->V
, drbg_blocklen(drbg
));
553 * 10.2.1.2 step 2.2 */
554 ret
= drbg_kcapi_sym(drbg
, drbg
->C
, temp
+ len
, &cipherin
);
557 /* 10.2.1.2 step 2.3 and 3 */
558 len
+= drbg_blocklen(drbg
);
561 /* 10.2.1.2 step 4 */
564 for (len
= 0; len
< drbg_statelen(drbg
); len
++) {
565 *temp_p
^= *df_data_p
;
566 df_data_p
++; temp_p
++;
569 /* 10.2.1.2 step 5 */
570 memcpy(drbg
->C
, temp
, drbg_keylen(drbg
));
571 /* 10.2.1.2 step 6 */
572 memcpy(drbg
->V
, temp
+ drbg_keylen(drbg
), drbg_blocklen(drbg
));
576 memset(temp
, 0, drbg_statelen(drbg
) + drbg_blocklen(drbg
));
578 memset(df_data
, 0, drbg_statelen(drbg
));
583 * scratchpad use: drbg_ctr_update is called independently from
584 * drbg_ctr_extract_bytes. Therefore, the scratchpad is reused
586 /* Generate function of CTR DRBG as defined in 10.2.1.5.2 */
587 static int drbg_ctr_generate(struct drbg_state
*drbg
,
588 unsigned char *buf
, unsigned int buflen
,
589 struct list_head
*addtl
)
593 struct drbg_string data
;
595 memset(drbg
->scratchpad
, 0, drbg_blocklen(drbg
));
597 /* 10.2.1.5.2 step 2 */
598 if (addtl
&& !list_empty(addtl
)) {
599 ret
= drbg_ctr_update(drbg
, addtl
, 2);
604 /* 10.2.1.5.2 step 4.1 */
605 crypto_inc(drbg
->V
, drbg_blocklen(drbg
));
606 drbg_string_fill(&data
, drbg
->V
, drbg_blocklen(drbg
));
607 while (len
< buflen
) {
609 /* 10.2.1.5.2 step 4.2 */
610 ret
= drbg_kcapi_sym(drbg
, drbg
->C
, drbg
->scratchpad
, &data
);
615 outlen
= (drbg_blocklen(drbg
) < (buflen
- len
)) ?
616 drbg_blocklen(drbg
) : (buflen
- len
);
617 if (!drbg_fips_continuous_test(drbg
, drbg
->scratchpad
)) {
618 /* 10.2.1.5.2 step 6 */
619 crypto_inc(drbg
->V
, drbg_blocklen(drbg
));
622 /* 10.2.1.5.2 step 4.3 */
623 memcpy(buf
+ len
, drbg
->scratchpad
, outlen
);
625 /* 10.2.1.5.2 step 6 */
627 crypto_inc(drbg
->V
, drbg_blocklen(drbg
));
630 /* 10.2.1.5.2 step 6 */
631 ret
= drbg_ctr_update(drbg
, NULL
, 3);
636 memset(drbg
->scratchpad
, 0, drbg_blocklen(drbg
));
640 static struct drbg_state_ops drbg_ctr_ops
= {
641 .update
= drbg_ctr_update
,
642 .generate
= drbg_ctr_generate
,
643 .crypto_init
= drbg_init_sym_kernel
,
644 .crypto_fini
= drbg_fini_sym_kernel
,
646 #endif /* CONFIG_CRYPTO_DRBG_CTR */
648 /******************************************************************
649 * HMAC DRBG callback functions
650 ******************************************************************/
652 #if defined(CONFIG_CRYPTO_DRBG_HASH) || defined(CONFIG_CRYPTO_DRBG_HMAC)
653 static int drbg_kcapi_hash(struct drbg_state
*drbg
, const unsigned char *key
,
654 unsigned char *outval
, const struct list_head
*in
);
655 static int drbg_init_hash_kernel(struct drbg_state
*drbg
);
656 static int drbg_fini_hash_kernel(struct drbg_state
*drbg
);
657 #endif /* (CONFIG_CRYPTO_DRBG_HASH || CONFIG_CRYPTO_DRBG_HMAC) */
659 #ifdef CONFIG_CRYPTO_DRBG_HMAC
660 #define CRYPTO_DRBG_HMAC_STRING "HMAC "
661 MODULE_ALIAS_CRYPTO("drbg_pr_hmac_sha512");
662 MODULE_ALIAS_CRYPTO("drbg_nopr_hmac_sha512");
663 MODULE_ALIAS_CRYPTO("drbg_pr_hmac_sha384");
664 MODULE_ALIAS_CRYPTO("drbg_nopr_hmac_sha384");
665 MODULE_ALIAS_CRYPTO("drbg_pr_hmac_sha256");
666 MODULE_ALIAS_CRYPTO("drbg_nopr_hmac_sha256");
667 MODULE_ALIAS_CRYPTO("drbg_pr_hmac_sha1");
668 MODULE_ALIAS_CRYPTO("drbg_nopr_hmac_sha1");
670 /* update function of HMAC DRBG as defined in 10.1.2.2 */
671 static int drbg_hmac_update(struct drbg_state
*drbg
, struct list_head
*seed
,
676 struct drbg_string seed1
, seed2
, vdata
;
678 LIST_HEAD(vdatalist
);
681 /* 10.1.2.3 step 2 -- memset(0) of C is implicit with kzalloc */
682 memset(drbg
->V
, 1, drbg_statelen(drbg
));
684 drbg_string_fill(&seed1
, drbg
->V
, drbg_statelen(drbg
));
685 list_add_tail(&seed1
.list
, &seedlist
);
686 /* buffer of seed2 will be filled in for loop below with one byte */
687 drbg_string_fill(&seed2
, NULL
, 1);
688 list_add_tail(&seed2
.list
, &seedlist
);
689 /* input data of seed is allowed to be NULL at this point */
691 list_splice_tail(seed
, &seedlist
);
693 drbg_string_fill(&vdata
, drbg
->V
, drbg_statelen(drbg
));
694 list_add_tail(&vdata
.list
, &vdatalist
);
695 for (i
= 2; 0 < i
; i
--) {
696 /* first round uses 0x0, second 0x1 */
697 unsigned char prefix
= DRBG_PREFIX0
;
699 prefix
= DRBG_PREFIX1
;
700 /* 10.1.2.2 step 1 and 4 -- concatenation and HMAC for key */
702 ret
= drbg_kcapi_hash(drbg
, drbg
->C
, drbg
->C
, &seedlist
);
706 /* 10.1.2.2 step 2 and 5 -- HMAC for V */
707 ret
= drbg_kcapi_hash(drbg
, drbg
->C
, drbg
->V
, &vdatalist
);
711 /* 10.1.2.2 step 3 */
719 /* generate function of HMAC DRBG as defined in 10.1.2.5 */
720 static int drbg_hmac_generate(struct drbg_state
*drbg
,
723 struct list_head
*addtl
)
727 struct drbg_string data
;
730 /* 10.1.2.5 step 2 */
731 if (addtl
&& !list_empty(addtl
)) {
732 ret
= drbg_hmac_update(drbg
, addtl
, 1);
737 drbg_string_fill(&data
, drbg
->V
, drbg_statelen(drbg
));
738 list_add_tail(&data
.list
, &datalist
);
739 while (len
< buflen
) {
740 unsigned int outlen
= 0;
741 /* 10.1.2.5 step 4.1 */
742 ret
= drbg_kcapi_hash(drbg
, drbg
->C
, drbg
->V
, &datalist
);
745 outlen
= (drbg_blocklen(drbg
) < (buflen
- len
)) ?
746 drbg_blocklen(drbg
) : (buflen
- len
);
747 if (!drbg_fips_continuous_test(drbg
, drbg
->V
))
750 /* 10.1.2.5 step 4.2 */
751 memcpy(buf
+ len
, drbg
->V
, outlen
);
755 /* 10.1.2.5 step 6 */
756 if (addtl
&& !list_empty(addtl
))
757 ret
= drbg_hmac_update(drbg
, addtl
, 1);
759 ret
= drbg_hmac_update(drbg
, NULL
, 1);
766 static struct drbg_state_ops drbg_hmac_ops
= {
767 .update
= drbg_hmac_update
,
768 .generate
= drbg_hmac_generate
,
769 .crypto_init
= drbg_init_hash_kernel
,
770 .crypto_fini
= drbg_fini_hash_kernel
,
773 #endif /* CONFIG_CRYPTO_DRBG_HMAC */
775 /******************************************************************
776 * Hash DRBG callback functions
777 ******************************************************************/
779 #ifdef CONFIG_CRYPTO_DRBG_HASH
780 #define CRYPTO_DRBG_HASH_STRING "HASH "
781 MODULE_ALIAS_CRYPTO("drbg_pr_sha512");
782 MODULE_ALIAS_CRYPTO("drbg_nopr_sha512");
783 MODULE_ALIAS_CRYPTO("drbg_pr_sha384");
784 MODULE_ALIAS_CRYPTO("drbg_nopr_sha384");
785 MODULE_ALIAS_CRYPTO("drbg_pr_sha256");
786 MODULE_ALIAS_CRYPTO("drbg_nopr_sha256");
787 MODULE_ALIAS_CRYPTO("drbg_pr_sha1");
788 MODULE_ALIAS_CRYPTO("drbg_nopr_sha1");
793 * @dst buffer to increment
796 static inline void drbg_add_buf(unsigned char *dst
, size_t dstlen
,
797 const unsigned char *add
, size_t addlen
)
799 /* implied: dstlen > addlen */
800 unsigned char *dstptr
;
801 const unsigned char *addptr
;
802 unsigned int remainder
= 0;
805 dstptr
= dst
+ (dstlen
-1);
806 addptr
= add
+ (addlen
-1);
808 remainder
+= *dstptr
+ *addptr
;
809 *dstptr
= remainder
& 0xff;
811 len
--; dstptr
--; addptr
--;
813 len
= dstlen
- addlen
;
814 while (len
&& remainder
> 0) {
815 remainder
= *dstptr
+ 1;
816 *dstptr
= remainder
& 0xff;
823 * scratchpad usage: as drbg_hash_update and drbg_hash_df are used
824 * interlinked, the scratchpad is used as follows:
826 * start: drbg->scratchpad
827 * length: drbg_statelen(drbg)
829 * start: drbg->scratchpad + drbg_statelen(drbg)
830 * length: drbg_blocklen(drbg)
832 * drbg_hash_process_addtl uses the scratchpad, but fully completes
833 * before either of the functions mentioned before are invoked. Therefore,
834 * drbg_hash_process_addtl does not need to be specifically considered.
837 /* Derivation Function for Hash DRBG as defined in 10.4.1 */
838 static int drbg_hash_df(struct drbg_state
*drbg
,
839 unsigned char *outval
, size_t outlen
,
840 struct list_head
*entropylist
)
844 unsigned char input
[5];
845 unsigned char *tmp
= drbg
->scratchpad
+ drbg_statelen(drbg
);
846 struct drbg_string data
;
848 memset(tmp
, 0, drbg_blocklen(drbg
));
852 drbg_cpu_to_be32((outlen
* 8), &input
[1]);
854 /* 10.4.1 step 4.1 -- concatenation of data for input into hash */
855 drbg_string_fill(&data
, input
, 5);
856 list_add(&data
.list
, entropylist
);
859 while (len
< outlen
) {
861 /* 10.4.1 step 4.1 */
862 ret
= drbg_kcapi_hash(drbg
, NULL
, tmp
, entropylist
);
865 /* 10.4.1 step 4.2 */
867 blocklen
= (drbg_blocklen(drbg
) < (outlen
- len
)) ?
868 drbg_blocklen(drbg
) : (outlen
- len
);
869 memcpy(outval
+ len
, tmp
, blocklen
);
874 memset(tmp
, 0, drbg_blocklen(drbg
));
878 /* update function for Hash DRBG as defined in 10.1.1.2 / 10.1.1.3 */
879 static int drbg_hash_update(struct drbg_state
*drbg
, struct list_head
*seed
,
883 struct drbg_string data1
, data2
;
885 LIST_HEAD(datalist2
);
886 unsigned char *V
= drbg
->scratchpad
;
887 unsigned char prefix
= DRBG_PREFIX1
;
889 memset(drbg
->scratchpad
, 0, drbg_statelen(drbg
));
894 /* 10.1.1.3 step 1 */
895 memcpy(V
, drbg
->V
, drbg_statelen(drbg
));
896 drbg_string_fill(&data1
, &prefix
, 1);
897 list_add_tail(&data1
.list
, &datalist
);
898 drbg_string_fill(&data2
, V
, drbg_statelen(drbg
));
899 list_add_tail(&data2
.list
, &datalist
);
901 list_splice_tail(seed
, &datalist
);
903 /* 10.1.1.2 / 10.1.1.3 step 2 and 3 */
904 ret
= drbg_hash_df(drbg
, drbg
->V
, drbg_statelen(drbg
), &datalist
);
908 /* 10.1.1.2 / 10.1.1.3 step 4 */
909 prefix
= DRBG_PREFIX0
;
910 drbg_string_fill(&data1
, &prefix
, 1);
911 list_add_tail(&data1
.list
, &datalist2
);
912 drbg_string_fill(&data2
, drbg
->V
, drbg_statelen(drbg
));
913 list_add_tail(&data2
.list
, &datalist2
);
914 /* 10.1.1.2 / 10.1.1.3 step 4 */
915 ret
= drbg_hash_df(drbg
, drbg
->C
, drbg_statelen(drbg
), &datalist2
);
918 memset(drbg
->scratchpad
, 0, drbg_statelen(drbg
));
922 /* processing of additional information string for Hash DRBG */
923 static int drbg_hash_process_addtl(struct drbg_state
*drbg
,
924 struct list_head
*addtl
)
927 struct drbg_string data1
, data2
;
929 unsigned char prefix
= DRBG_PREFIX2
;
931 /* this is value w as per documentation */
932 memset(drbg
->scratchpad
, 0, drbg_blocklen(drbg
));
934 /* 10.1.1.4 step 2 */
935 if (!addtl
|| list_empty(addtl
))
938 /* 10.1.1.4 step 2a */
939 drbg_string_fill(&data1
, &prefix
, 1);
940 drbg_string_fill(&data2
, drbg
->V
, drbg_statelen(drbg
));
941 list_add_tail(&data1
.list
, &datalist
);
942 list_add_tail(&data2
.list
, &datalist
);
943 list_splice_tail(addtl
, &datalist
);
944 ret
= drbg_kcapi_hash(drbg
, NULL
, drbg
->scratchpad
, &datalist
);
948 /* 10.1.1.4 step 2b */
949 drbg_add_buf(drbg
->V
, drbg_statelen(drbg
),
950 drbg
->scratchpad
, drbg_blocklen(drbg
));
953 memset(drbg
->scratchpad
, 0, drbg_blocklen(drbg
));
957 /* Hashgen defined in 10.1.1.4 */
958 static int drbg_hash_hashgen(struct drbg_state
*drbg
,
964 unsigned char *src
= drbg
->scratchpad
;
965 unsigned char *dst
= drbg
->scratchpad
+ drbg_statelen(drbg
);
966 struct drbg_string data
;
969 memset(src
, 0, drbg_statelen(drbg
));
970 memset(dst
, 0, drbg_blocklen(drbg
));
972 /* 10.1.1.4 step hashgen 2 */
973 memcpy(src
, drbg
->V
, drbg_statelen(drbg
));
975 drbg_string_fill(&data
, src
, drbg_statelen(drbg
));
976 list_add_tail(&data
.list
, &datalist
);
977 while (len
< buflen
) {
978 unsigned int outlen
= 0;
979 /* 10.1.1.4 step hashgen 4.1 */
980 ret
= drbg_kcapi_hash(drbg
, NULL
, dst
, &datalist
);
985 outlen
= (drbg_blocklen(drbg
) < (buflen
- len
)) ?
986 drbg_blocklen(drbg
) : (buflen
- len
);
987 if (!drbg_fips_continuous_test(drbg
, dst
)) {
988 crypto_inc(src
, drbg_statelen(drbg
));
991 /* 10.1.1.4 step hashgen 4.2 */
992 memcpy(buf
+ len
, dst
, outlen
);
994 /* 10.1.1.4 hashgen step 4.3 */
996 crypto_inc(src
, drbg_statelen(drbg
));
1000 memset(drbg
->scratchpad
, 0,
1001 (drbg_statelen(drbg
) + drbg_blocklen(drbg
)));
1005 /* generate function for Hash DRBG as defined in 10.1.1.4 */
1006 static int drbg_hash_generate(struct drbg_state
*drbg
,
1007 unsigned char *buf
, unsigned int buflen
,
1008 struct list_head
*addtl
)
1013 unsigned char req
[8];
1016 unsigned char prefix
= DRBG_PREFIX3
;
1017 struct drbg_string data1
, data2
;
1018 LIST_HEAD(datalist
);
1020 /* 10.1.1.4 step 2 */
1021 ret
= drbg_hash_process_addtl(drbg
, addtl
);
1024 /* 10.1.1.4 step 3 */
1025 len
= drbg_hash_hashgen(drbg
, buf
, buflen
);
1027 /* this is the value H as documented in 10.1.1.4 */
1028 memset(drbg
->scratchpad
, 0, drbg_blocklen(drbg
));
1029 /* 10.1.1.4 step 4 */
1030 drbg_string_fill(&data1
, &prefix
, 1);
1031 list_add_tail(&data1
.list
, &datalist
);
1032 drbg_string_fill(&data2
, drbg
->V
, drbg_statelen(drbg
));
1033 list_add_tail(&data2
.list
, &datalist
);
1034 ret
= drbg_kcapi_hash(drbg
, NULL
, drbg
->scratchpad
, &datalist
);
1040 /* 10.1.1.4 step 5 */
1041 drbg_add_buf(drbg
->V
, drbg_statelen(drbg
),
1042 drbg
->scratchpad
, drbg_blocklen(drbg
));
1043 drbg_add_buf(drbg
->V
, drbg_statelen(drbg
),
1044 drbg
->C
, drbg_statelen(drbg
));
1045 u
.req_int
= cpu_to_be64(drbg
->reseed_ctr
);
1046 drbg_add_buf(drbg
->V
, drbg_statelen(drbg
), u
.req
, 8);
1049 memset(drbg
->scratchpad
, 0, drbg_blocklen(drbg
));
1054 * scratchpad usage: as update and generate are used isolated, both
1055 * can use the scratchpad
1057 static struct drbg_state_ops drbg_hash_ops
= {
1058 .update
= drbg_hash_update
,
1059 .generate
= drbg_hash_generate
,
1060 .crypto_init
= drbg_init_hash_kernel
,
1061 .crypto_fini
= drbg_fini_hash_kernel
,
1063 #endif /* CONFIG_CRYPTO_DRBG_HASH */
1065 /******************************************************************
1066 * Functions common for DRBG implementations
1067 ******************************************************************/
1070 * Seeding or reseeding of the DRBG
1072 * @drbg: DRBG state struct
1073 * @pers: personalization / additional information buffer
1074 * @reseed: 0 for initial seed process, 1 for reseeding
1078 * error value otherwise
1080 static int drbg_seed(struct drbg_state
*drbg
, struct drbg_string
*pers
,
1084 unsigned char *entropy
= NULL
;
1085 size_t entropylen
= 0;
1086 struct drbg_string data1
;
1087 LIST_HEAD(seedlist
);
1089 /* 9.1 / 9.2 / 9.3.1 step 3 */
1090 if (pers
&& pers
->len
> (drbg_max_addtl(drbg
))) {
1091 pr_devel("DRBG: personalization string too long %zu\n",
1096 if (drbg
->test_data
&& drbg
->test_data
->testentropy
) {
1097 drbg_string_fill(&data1
, drbg
->test_data
->testentropy
->buf
,
1098 drbg
->test_data
->testentropy
->len
);
1099 pr_devel("DRBG: using test entropy\n");
1102 * Gather entropy equal to the security strength of the DRBG.
1103 * With a derivation function, a nonce is required in addition
1104 * to the entropy. A nonce must be at least 1/2 of the security
1105 * strength of the DRBG in size. Thus, entropy * nonce is 3/2
1106 * of the strength. The consideration of a nonce is only
1107 * applicable during initial seeding.
1109 entropylen
= drbg_sec_strength(drbg
->core
->flags
);
1113 entropylen
= ((entropylen
+ 1) / 2) * 3;
1114 pr_devel("DRBG: (re)seeding with %zu bytes of entropy\n",
1116 entropy
= kzalloc(entropylen
, GFP_KERNEL
);
1119 get_random_bytes(entropy
, entropylen
);
1120 drbg_string_fill(&data1
, entropy
, entropylen
);
1122 list_add_tail(&data1
.list
, &seedlist
);
1125 * concatenation of entropy with personalization str / addtl input)
1126 * the variable pers is directly handed in by the caller, so check its
1127 * contents whether it is appropriate
1129 if (pers
&& pers
->buf
&& 0 < pers
->len
) {
1130 list_add_tail(&pers
->list
, &seedlist
);
1131 pr_devel("DRBG: using personalization string\n");
1135 memset(drbg
->V
, 0, drbg_statelen(drbg
));
1136 memset(drbg
->C
, 0, drbg_statelen(drbg
));
1139 ret
= drbg
->d_ops
->update(drbg
, &seedlist
, reseed
);
1143 drbg
->seeded
= true;
1144 /* 10.1.1.2 / 10.1.1.3 step 5 */
1145 drbg
->reseed_ctr
= 1;
1152 /* Free all substructures in a DRBG state without the DRBG state structure */
1153 static inline void drbg_dealloc_state(struct drbg_state
*drbg
)
1161 kzfree(drbg
->scratchpad
);
1162 drbg
->scratchpad
= NULL
;
1163 drbg
->reseed_ctr
= 0;
1164 #ifdef CONFIG_CRYPTO_FIPS
1167 drbg
->fips_primed
= false;
1172 * Allocate all sub-structures for a DRBG state.
1173 * The DRBG state structure must already be allocated.
1175 static inline int drbg_alloc_state(struct drbg_state
*drbg
)
1178 unsigned int sb_size
= 0;
1180 drbg
->V
= kmalloc(drbg_statelen(drbg
), GFP_KERNEL
);
1183 drbg
->C
= kmalloc(drbg_statelen(drbg
), GFP_KERNEL
);
1186 #ifdef CONFIG_CRYPTO_FIPS
1187 drbg
->prev
= kmalloc(drbg_blocklen(drbg
), GFP_KERNEL
);
1190 drbg
->fips_primed
= false;
1192 /* scratchpad is only generated for CTR and Hash */
1193 if (drbg
->core
->flags
& DRBG_HMAC
)
1195 else if (drbg
->core
->flags
& DRBG_CTR
)
1196 sb_size
= drbg_statelen(drbg
) + drbg_blocklen(drbg
) + /* temp */
1197 drbg_statelen(drbg
) + /* df_data */
1198 drbg_blocklen(drbg
) + /* pad */
1199 drbg_blocklen(drbg
) + /* iv */
1200 drbg_statelen(drbg
) + drbg_blocklen(drbg
); /* temp */
1202 sb_size
= drbg_statelen(drbg
) + drbg_blocklen(drbg
);
1205 drbg
->scratchpad
= kzalloc(sb_size
, GFP_KERNEL
);
1206 if (!drbg
->scratchpad
)
1209 spin_lock_init(&drbg
->drbg_lock
);
1213 drbg_dealloc_state(drbg
);
1218 * Strategy to avoid holding long term locks: generate a shadow copy of DRBG
1219 * and perform all operations on this shadow copy. After finishing, restore
1220 * the updated state of the shadow copy into original drbg state. This way,
1221 * only the read and write operations of the original drbg state must be
1224 static inline void drbg_copy_drbg(struct drbg_state
*src
,
1225 struct drbg_state
*dst
)
1229 memcpy(dst
->V
, src
->V
, drbg_statelen(src
));
1230 memcpy(dst
->C
, src
->C
, drbg_statelen(src
));
1231 dst
->reseed_ctr
= src
->reseed_ctr
;
1232 dst
->seeded
= src
->seeded
;
1234 #ifdef CONFIG_CRYPTO_FIPS
1235 dst
->fips_primed
= src
->fips_primed
;
1236 memcpy(dst
->prev
, src
->prev
, drbg_blocklen(src
));
1240 * scratchpad is initialized drbg_alloc_state;
1241 * priv_data is initialized with call to crypto_init;
1242 * d_ops and core are set outside, as these parameters are const;
1243 * test_data is set outside to prevent it being copied back.
1247 static int drbg_make_shadow(struct drbg_state
*drbg
, struct drbg_state
**shadow
)
1250 struct drbg_state
*tmp
= NULL
;
1252 tmp
= kzalloc(sizeof(struct drbg_state
), GFP_KERNEL
);
1256 /* read-only data as they are defined as const, no lock needed */
1257 tmp
->core
= drbg
->core
;
1258 tmp
->d_ops
= drbg
->d_ops
;
1260 ret
= drbg_alloc_state(tmp
);
1264 spin_lock_bh(&drbg
->drbg_lock
);
1265 drbg_copy_drbg(drbg
, tmp
);
1266 /* only make a link to the test buffer, as we only read that data */
1267 tmp
->test_data
= drbg
->test_data
;
1268 spin_unlock_bh(&drbg
->drbg_lock
);
1277 static void drbg_restore_shadow(struct drbg_state
*drbg
,
1278 struct drbg_state
**shadow
)
1280 struct drbg_state
*tmp
= *shadow
;
1282 spin_lock_bh(&drbg
->drbg_lock
);
1283 drbg_copy_drbg(tmp
, drbg
);
1284 spin_unlock_bh(&drbg
->drbg_lock
);
1285 drbg_dealloc_state(tmp
);
1290 /*************************************************************************
1291 * DRBG interface functions
1292 *************************************************************************/
1295 * DRBG generate function as required by SP800-90A - this function
1296 * generates random numbers
1298 * @drbg DRBG state handle
1299 * @buf Buffer where to store the random numbers -- the buffer must already
1300 * be pre-allocated by caller
1301 * @buflen Length of output buffer - this value defines the number of random
1302 * bytes pulled from DRBG
1303 * @addtl Additional input that is mixed into state, may be NULL -- note
1304 * the entropy is pulled by the DRBG internally unconditionally
1305 * as defined in SP800-90A. The additional input is mixed into
1306 * the state in addition to the pulled entropy.
1308 * return: generated number of bytes
1310 static int drbg_generate(struct drbg_state
*drbg
,
1311 unsigned char *buf
, unsigned int buflen
,
1312 struct drbg_string
*addtl
)
1315 struct drbg_state
*shadow
= NULL
;
1316 LIST_HEAD(addtllist
);
1317 struct drbg_string timestamp
;
1320 unsigned char char_cycles
[sizeof(cycles_t
)];
1323 if (0 == buflen
|| !buf
) {
1324 pr_devel("DRBG: no output buffer provided\n");
1327 if (addtl
&& NULL
== addtl
->buf
&& 0 < addtl
->len
) {
1328 pr_devel("DRBG: wrong format of additional information\n");
1332 len
= drbg_make_shadow(drbg
, &shadow
);
1334 pr_devel("DRBG: shadow copy cannot be generated\n");
1340 if (buflen
> (drbg_max_request_bytes(shadow
))) {
1341 pr_devel("DRBG: requested random numbers too large %u\n",
1346 /* 9.3.1 step 3 is implicit with the chosen DRBG */
1349 if (addtl
&& addtl
->len
> (drbg_max_addtl(shadow
))) {
1350 pr_devel("DRBG: additional information string too long %zu\n",
1354 /* 9.3.1 step 5 is implicit with the chosen DRBG */
1357 * 9.3.1 step 6 and 9 supplemented by 9.3.2 step c is implemented
1358 * here. The spec is a bit convoluted here, we make it simpler.
1360 if ((drbg_max_requests(shadow
)) < shadow
->reseed_ctr
)
1361 shadow
->seeded
= false;
1363 /* allocate cipher handle */
1364 len
= shadow
->d_ops
->crypto_init(shadow
);
1368 if (shadow
->pr
|| !shadow
->seeded
) {
1369 pr_devel("DRBG: reseeding before generation (prediction "
1370 "resistance: %s, state %s)\n",
1371 drbg
->pr
? "true" : "false",
1372 drbg
->seeded
? "seeded" : "unseeded");
1373 /* 9.3.1 steps 7.1 through 7.3 */
1374 len
= drbg_seed(shadow
, addtl
, true);
1377 /* 9.3.1 step 7.4 */
1382 * Mix the time stamp into the DRBG state if the DRBG is not in
1383 * test mode. If there are two callers invoking the DRBG at the same
1384 * time, i.e. before the first caller merges its shadow state back,
1385 * both callers would obtain the same random number stream without
1386 * changing the state here.
1388 if (!drbg
->test_data
) {
1389 now
.cycles
= random_get_entropy();
1390 drbg_string_fill(×tamp
, now
.char_cycles
, sizeof(cycles_t
));
1391 list_add_tail(×tamp
.list
, &addtllist
);
1393 if (addtl
&& 0 < addtl
->len
)
1394 list_add_tail(&addtl
->list
, &addtllist
);
1395 /* 9.3.1 step 8 and 10 */
1396 len
= shadow
->d_ops
->generate(shadow
, buf
, buflen
, &addtllist
);
1398 /* 10.1.1.4 step 6, 10.1.2.5 step 7, 10.2.1.5.2 step 7 */
1399 shadow
->reseed_ctr
++;
1404 * Section 11.3.3 requires to re-perform self tests after some
1405 * generated random numbers. The chosen value after which self
1406 * test is performed is arbitrary, but it should be reasonable.
1407 * However, we do not perform the self tests because of the following
1408 * reasons: it is mathematically impossible that the initial self tests
1409 * were successfully and the following are not. If the initial would
1410 * pass and the following would not, the kernel integrity is violated.
1411 * In this case, the entire kernel operation is questionable and it
1412 * is unlikely that the integrity violation only affects the
1413 * correct operation of the DRBG.
1415 * Albeit the following code is commented out, it is provided in
1416 * case somebody has a need to implement the test of 11.3.3.
1419 if (shadow
->reseed_ctr
&& !(shadow
->reseed_ctr
% 4096)) {
1421 pr_devel("DRBG: start to perform self test\n");
1422 if (drbg
->core
->flags
& DRBG_HMAC
)
1423 err
= alg_test("drbg_pr_hmac_sha256",
1424 "drbg_pr_hmac_sha256", 0, 0);
1425 else if (drbg
->core
->flags
& DRBG_CTR
)
1426 err
= alg_test("drbg_pr_ctr_aes128",
1427 "drbg_pr_ctr_aes128", 0, 0);
1429 err
= alg_test("drbg_pr_sha256",
1430 "drbg_pr_sha256", 0, 0);
1432 pr_err("DRBG: periodical self test failed\n");
1434 * uninstantiate implies that from now on, only errors
1435 * are returned when reusing this DRBG cipher handle
1437 drbg_uninstantiate(drbg
);
1438 drbg_dealloc_state(shadow
);
1442 pr_devel("DRBG: self test successful\n");
1448 shadow
->d_ops
->crypto_fini(shadow
);
1449 drbg_restore_shadow(drbg
, &shadow
);
1454 * Wrapper around drbg_generate which can pull arbitrary long strings
1455 * from the DRBG without hitting the maximum request limitation.
1457 * Parameters: see drbg_generate
1458 * Return codes: see drbg_generate -- if one drbg_generate request fails,
1459 * the entire drbg_generate_long request fails
1461 static int drbg_generate_long(struct drbg_state
*drbg
,
1462 unsigned char *buf
, unsigned int buflen
,
1463 struct drbg_string
*addtl
)
1466 unsigned int slice
= 0;
1469 unsigned int chunk
= 0;
1470 slice
= ((buflen
- len
) / drbg_max_request_bytes(drbg
));
1471 chunk
= slice
? drbg_max_request_bytes(drbg
) : (buflen
- len
);
1472 tmplen
= drbg_generate(drbg
, buf
+ len
, chunk
, addtl
);
1476 } while (slice
> 0 && (len
< buflen
));
1481 * DRBG instantiation function as required by SP800-90A - this function
1482 * sets up the DRBG handle, performs the initial seeding and all sanity
1483 * checks required by SP800-90A
1485 * @drbg memory of state -- if NULL, new memory is allocated
1486 * @pers Personalization string that is mixed into state, may be NULL -- note
1487 * the entropy is pulled by the DRBG internally unconditionally
1488 * as defined in SP800-90A. The additional input is mixed into
1489 * the state in addition to the pulled entropy.
1490 * @coreref reference to core
1491 * @pr prediction resistance enabled
1495 * error value otherwise
1497 static int drbg_instantiate(struct drbg_state
*drbg
, struct drbg_string
*pers
,
1498 int coreref
, bool pr
)
1502 pr_devel("DRBG: Initializing DRBG core %d with prediction resistance "
1503 "%s\n", coreref
, pr
? "enabled" : "disabled");
1504 drbg
->core
= &drbg_cores
[coreref
];
1506 drbg
->seeded
= false;
1507 switch (drbg
->core
->flags
& DRBG_TYPE_MASK
) {
1508 #ifdef CONFIG_CRYPTO_DRBG_HMAC
1510 drbg
->d_ops
= &drbg_hmac_ops
;
1512 #endif /* CONFIG_CRYPTO_DRBG_HMAC */
1513 #ifdef CONFIG_CRYPTO_DRBG_HASH
1515 drbg
->d_ops
= &drbg_hash_ops
;
1517 #endif /* CONFIG_CRYPTO_DRBG_HASH */
1518 #ifdef CONFIG_CRYPTO_DRBG_CTR
1520 drbg
->d_ops
= &drbg_ctr_ops
;
1522 #endif /* CONFIG_CRYPTO_DRBG_CTR */
1527 /* 9.1 step 1 is implicit with the selected DRBG type */
1530 * 9.1 step 2 is implicit as caller can select prediction resistance
1531 * and the flag is copied into drbg->flags --
1532 * all DRBG types support prediction resistance
1535 /* 9.1 step 4 is implicit in drbg_sec_strength */
1537 ret
= drbg_alloc_state(drbg
);
1542 if (drbg
->d_ops
->crypto_init(drbg
))
1544 ret
= drbg_seed(drbg
, pers
, false);
1545 drbg
->d_ops
->crypto_fini(drbg
);
1552 drbg_dealloc_state(drbg
);
1557 * DRBG uninstantiate function as required by SP800-90A - this function
1558 * frees all buffers and the DRBG handle
1560 * @drbg DRBG state handle
1565 static int drbg_uninstantiate(struct drbg_state
*drbg
)
1567 spin_lock_bh(&drbg
->drbg_lock
);
1568 drbg_dealloc_state(drbg
);
1569 /* no scrubbing of test_data -- this shall survive an uninstantiate */
1570 spin_unlock_bh(&drbg
->drbg_lock
);
1575 * Helper function for setting the test data in the DRBG
1577 * @drbg DRBG state handle
1578 * @test_data test data to sets
1580 static inline void drbg_set_testdata(struct drbg_state
*drbg
,
1581 struct drbg_test_data
*test_data
)
1583 if (!test_data
|| !test_data
->testentropy
)
1585 spin_lock_bh(&drbg
->drbg_lock
);
1586 drbg
->test_data
= test_data
;
1587 spin_unlock_bh(&drbg
->drbg_lock
);
1590 /***************************************************************
1591 * Kernel crypto API cipher invocations requested by DRBG
1592 ***************************************************************/
1594 #if defined(CONFIG_CRYPTO_DRBG_HASH) || defined(CONFIG_CRYPTO_DRBG_HMAC)
1596 struct shash_desc shash
;
1600 static int drbg_init_hash_kernel(struct drbg_state
*drbg
)
1602 struct sdesc
*sdesc
;
1603 struct crypto_shash
*tfm
;
1605 tfm
= crypto_alloc_shash(drbg
->core
->backend_cra_name
, 0, 0);
1607 pr_info("DRBG: could not allocate digest TFM handle\n");
1608 return PTR_ERR(tfm
);
1610 BUG_ON(drbg_blocklen(drbg
) != crypto_shash_digestsize(tfm
));
1611 sdesc
= kzalloc(sizeof(struct shash_desc
) + crypto_shash_descsize(tfm
),
1614 crypto_free_shash(tfm
);
1618 sdesc
->shash
.tfm
= tfm
;
1619 sdesc
->shash
.flags
= 0;
1620 drbg
->priv_data
= sdesc
;
1624 static int drbg_fini_hash_kernel(struct drbg_state
*drbg
)
1626 struct sdesc
*sdesc
= (struct sdesc
*)drbg
->priv_data
;
1628 crypto_free_shash(sdesc
->shash
.tfm
);
1631 drbg
->priv_data
= NULL
;
1635 static int drbg_kcapi_hash(struct drbg_state
*drbg
, const unsigned char *key
,
1636 unsigned char *outval
, const struct list_head
*in
)
1638 struct sdesc
*sdesc
= (struct sdesc
*)drbg
->priv_data
;
1639 struct drbg_string
*input
= NULL
;
1642 crypto_shash_setkey(sdesc
->shash
.tfm
, key
, drbg_statelen(drbg
));
1643 crypto_shash_init(&sdesc
->shash
);
1644 list_for_each_entry(input
, in
, list
)
1645 crypto_shash_update(&sdesc
->shash
, input
->buf
, input
->len
);
1646 return crypto_shash_final(&sdesc
->shash
, outval
);
1648 #endif /* (CONFIG_CRYPTO_DRBG_HASH || CONFIG_CRYPTO_DRBG_HMAC) */
1650 #ifdef CONFIG_CRYPTO_DRBG_CTR
1651 static int drbg_init_sym_kernel(struct drbg_state
*drbg
)
1654 struct crypto_blkcipher
*tfm
;
1656 tfm
= crypto_alloc_blkcipher(drbg
->core
->backend_cra_name
, 0, 0);
1658 pr_info("DRBG: could not allocate cipher TFM handle\n");
1659 return PTR_ERR(tfm
);
1661 BUG_ON(drbg_blocklen(drbg
) != crypto_blkcipher_blocksize(tfm
));
1662 drbg
->priv_data
= tfm
;
1666 static int drbg_fini_sym_kernel(struct drbg_state
*drbg
)
1668 struct crypto_blkcipher
*tfm
=
1669 (struct crypto_blkcipher
*)drbg
->priv_data
;
1671 crypto_free_blkcipher(tfm
);
1672 drbg
->priv_data
= NULL
;
1676 static int drbg_kcapi_sym(struct drbg_state
*drbg
, const unsigned char *key
,
1677 unsigned char *outval
, const struct drbg_string
*in
)
1680 struct scatterlist sg_in
, sg_out
;
1681 struct blkcipher_desc desc
;
1682 struct crypto_blkcipher
*tfm
=
1683 (struct crypto_blkcipher
*)drbg
->priv_data
;
1687 crypto_blkcipher_setkey(tfm
, key
, (drbg_keylen(drbg
)));
1688 /* there is only component in *in */
1689 sg_init_one(&sg_in
, in
->buf
, in
->len
);
1690 sg_init_one(&sg_out
, outval
, drbg_blocklen(drbg
));
1691 ret
= crypto_blkcipher_encrypt(&desc
, &sg_out
, &sg_in
, in
->len
);
1695 #endif /* CONFIG_CRYPTO_DRBG_CTR */
1697 /***************************************************************
1698 * Kernel crypto API interface to register DRBG
1699 ***************************************************************/
1702 * Look up the DRBG flags by given kernel crypto API cra_name
1703 * The code uses the drbg_cores definition to do this
1705 * @cra_name kernel crypto API cra_name
1706 * @coreref reference to integer which is filled with the pointer to
1707 * the applicable core
1708 * @pr reference for setting prediction resistance
1712 static inline void drbg_convert_tfm_core(const char *cra_driver_name
,
1713 int *coreref
, bool *pr
)
1720 /* disassemble the names */
1721 if (!memcmp(cra_driver_name
, "drbg_nopr_", 10)) {
1724 } else if (!memcmp(cra_driver_name
, "drbg_pr_", 8)) {
1730 /* remove the first part */
1731 len
= strlen(cra_driver_name
) - start
;
1732 for (i
= 0; ARRAY_SIZE(drbg_cores
) > i
; i
++) {
1733 if (!memcmp(cra_driver_name
+ start
, drbg_cores
[i
].cra_name
,
1741 static int drbg_kcapi_init(struct crypto_tfm
*tfm
)
1743 struct drbg_state
*drbg
= crypto_tfm_ctx(tfm
);
1747 drbg_convert_tfm_core(crypto_tfm_alg_driver_name(tfm
), &coreref
, &pr
);
1749 * when personalization string is needed, the caller must call reset
1750 * and provide the personalization string as seed information
1752 return drbg_instantiate(drbg
, NULL
, coreref
, pr
);
1755 static void drbg_kcapi_cleanup(struct crypto_tfm
*tfm
)
1757 drbg_uninstantiate(crypto_tfm_ctx(tfm
));
1761 * Generate random numbers invoked by the kernel crypto API:
1762 * The API of the kernel crypto API is extended as follows:
1764 * If dlen is larger than zero, rdata is interpreted as the output buffer
1765 * where random data is to be stored.
1767 * If dlen is zero, rdata is interpreted as a pointer to a struct drbg_gen
1768 * which holds the additional information string that is used for the
1769 * DRBG generation process. The output buffer that is to be used to store
1770 * data is also pointed to by struct drbg_gen.
1772 static int drbg_kcapi_random(struct crypto_rng
*tfm
, u8
*rdata
,
1775 struct drbg_state
*drbg
= crypto_rng_ctx(tfm
);
1777 return drbg_generate_long(drbg
, rdata
, dlen
, NULL
);
1779 struct drbg_gen
*data
= (struct drbg_gen
*)rdata
;
1780 struct drbg_string addtl
;
1781 /* catch NULL pointer */
1784 drbg_set_testdata(drbg
, data
->test_data
);
1785 /* linked list variable is now local to allow modification */
1786 drbg_string_fill(&addtl
, data
->addtl
->buf
, data
->addtl
->len
);
1787 return drbg_generate_long(drbg
, data
->outbuf
, data
->outlen
,
1793 * Reset the DRBG invoked by the kernel crypto API
1794 * The reset implies a full re-initialization of the DRBG. Similar to the
1795 * generate function of drbg_kcapi_random, this function extends the
1796 * kernel crypto API interface with struct drbg_gen
1798 static int drbg_kcapi_reset(struct crypto_rng
*tfm
, u8
*seed
, unsigned int slen
)
1800 struct drbg_state
*drbg
= crypto_rng_ctx(tfm
);
1801 struct crypto_tfm
*tfm_base
= crypto_rng_tfm(tfm
);
1803 struct drbg_string seed_string
;
1806 drbg_uninstantiate(drbg
);
1807 drbg_convert_tfm_core(crypto_tfm_alg_driver_name(tfm_base
), &coreref
,
1810 drbg_string_fill(&seed_string
, seed
, slen
);
1811 return drbg_instantiate(drbg
, &seed_string
, coreref
, pr
);
1813 struct drbg_gen
*data
= (struct drbg_gen
*)seed
;
1814 /* allow invocation of API call with NULL, 0 */
1816 return drbg_instantiate(drbg
, NULL
, coreref
, pr
);
1817 drbg_set_testdata(drbg
, data
->test_data
);
1818 /* linked list variable is now local to allow modification */
1819 drbg_string_fill(&seed_string
, data
->addtl
->buf
,
1821 return drbg_instantiate(drbg
, &seed_string
, coreref
, pr
);
1825 /***************************************************************
1826 * Kernel module: code to load the module
1827 ***************************************************************/
1830 * Tests as defined in 11.3.2 in addition to the cipher tests: testing
1831 * of the error handling.
1833 * Note: testing of failing seed source as defined in 11.3.2 is not applicable
1834 * as seed source of get_random_bytes does not fail.
1836 * Note 2: There is no sensible way of testing the reseed counter
1837 * enforcement, so skip it.
1839 static inline int __init
drbg_healthcheck_sanity(void)
1841 #ifdef CONFIG_CRYPTO_FIPS
1843 #define OUTBUFLEN 16
1844 unsigned char buf
[OUTBUFLEN
];
1845 struct drbg_state
*drbg
= NULL
;
1850 struct drbg_string addtl
;
1851 size_t max_addtllen
, max_request_bytes
;
1853 /* only perform test in FIPS mode */
1857 #ifdef CONFIG_CRYPTO_DRBG_CTR
1858 drbg_convert_tfm_core("drbg_nopr_ctr_aes128", &coreref
, &pr
);
1859 #elif defined CONFIG_CRYPTO_DRBG_HASH
1860 drbg_convert_tfm_core("drbg_nopr_sha256", &coreref
, &pr
);
1862 drbg_convert_tfm_core("drbg_nopr_hmac_sha256", &coreref
, &pr
);
1865 drbg
= kzalloc(sizeof(struct drbg_state
), GFP_KERNEL
);
1870 * if the following tests fail, it is likely that there is a buffer
1871 * overflow as buf is much smaller than the requested or provided
1872 * string lengths -- in case the error handling does not succeed
1873 * we may get an OOPS. And we want to get an OOPS as this is a
1877 /* get a valid instance of DRBG for following tests */
1878 ret
= drbg_instantiate(drbg
, NULL
, coreref
, pr
);
1883 max_addtllen
= drbg_max_addtl(drbg
);
1884 max_request_bytes
= drbg_max_request_bytes(drbg
);
1885 drbg_string_fill(&addtl
, buf
, max_addtllen
+ 1);
1886 /* overflow addtllen with additonal info string */
1887 len
= drbg_generate(drbg
, buf
, OUTBUFLEN
, &addtl
);
1889 /* overflow max_bits */
1890 len
= drbg_generate(drbg
, buf
, (max_request_bytes
+ 1), NULL
);
1892 drbg_uninstantiate(drbg
);
1894 /* overflow max addtllen with personalization string */
1895 ret
= drbg_instantiate(drbg
, &addtl
, coreref
, pr
);
1897 /* all tests passed */
1900 pr_devel("DRBG: Sanity tests for failure code paths successfully "
1903 drbg_uninstantiate(drbg
);
1907 #else /* CONFIG_CRYPTO_FIPS */
1909 #endif /* CONFIG_CRYPTO_FIPS */
1912 static struct crypto_alg drbg_algs
[22];
1915 * Fill the array drbg_algs used to register the different DRBGs
1916 * with the kernel crypto API. To fill the array, the information
1917 * from drbg_cores[] is used.
1919 static inline void __init
drbg_fill_array(struct crypto_alg
*alg
,
1920 const struct drbg_core
*core
, int pr
)
1923 static int priority
= 100;
1925 memset(alg
, 0, sizeof(struct crypto_alg
));
1926 memcpy(alg
->cra_name
, "stdrng", 6);
1928 memcpy(alg
->cra_driver_name
, "drbg_pr_", 8);
1931 memcpy(alg
->cra_driver_name
, "drbg_nopr_", 10);
1934 memcpy(alg
->cra_driver_name
+ pos
, core
->cra_name
,
1935 strlen(core
->cra_name
));
1937 alg
->cra_priority
= priority
;
1940 * If FIPS mode enabled, the selected DRBG shall have the
1941 * highest cra_priority over other stdrng instances to ensure
1945 alg
->cra_priority
+= 200;
1947 alg
->cra_flags
= CRYPTO_ALG_TYPE_RNG
;
1948 alg
->cra_ctxsize
= sizeof(struct drbg_state
);
1949 alg
->cra_type
= &crypto_rng_type
;
1950 alg
->cra_module
= THIS_MODULE
;
1951 alg
->cra_init
= drbg_kcapi_init
;
1952 alg
->cra_exit
= drbg_kcapi_cleanup
;
1953 alg
->cra_u
.rng
.rng_make_random
= drbg_kcapi_random
;
1954 alg
->cra_u
.rng
.rng_reset
= drbg_kcapi_reset
;
1955 alg
->cra_u
.rng
.seedsize
= 0;
1958 static int __init
drbg_init(void)
1960 unsigned int i
= 0; /* pointer to drbg_algs */
1961 unsigned int j
= 0; /* pointer to drbg_cores */
1964 ret
= drbg_healthcheck_sanity();
1968 if (ARRAY_SIZE(drbg_cores
) * 2 > ARRAY_SIZE(drbg_algs
)) {
1969 pr_info("DRBG: Cannot register all DRBG types"
1970 "(slots needed: %zu, slots available: %zu)\n",
1971 ARRAY_SIZE(drbg_cores
) * 2, ARRAY_SIZE(drbg_algs
));
1976 * each DRBG definition can be used with PR and without PR, thus
1977 * we instantiate each DRBG in drbg_cores[] twice.
1979 * As the order of placing them into the drbg_algs array matters
1980 * (the later DRBGs receive a higher cra_priority) we register the
1981 * prediction resistance DRBGs first as the should not be too
1984 for (j
= 0; ARRAY_SIZE(drbg_cores
) > j
; j
++, i
++)
1985 drbg_fill_array(&drbg_algs
[i
], &drbg_cores
[j
], 1);
1986 for (j
= 0; ARRAY_SIZE(drbg_cores
) > j
; j
++, i
++)
1987 drbg_fill_array(&drbg_algs
[i
], &drbg_cores
[j
], 0);
1988 return crypto_register_algs(drbg_algs
, (ARRAY_SIZE(drbg_cores
) * 2));
1991 static void __exit
drbg_exit(void)
1993 crypto_unregister_algs(drbg_algs
, (ARRAY_SIZE(drbg_cores
) * 2));
1996 module_init(drbg_init
);
1997 module_exit(drbg_exit
);
1998 #ifndef CRYPTO_DRBG_HASH_STRING
1999 #define CRYPTO_DRBG_HASH_STRING ""
2001 #ifndef CRYPTO_DRBG_HMAC_STRING
2002 #define CRYPTO_DRBG_HMAC_STRING ""
2004 #ifndef CRYPTO_DRBG_CTR_STRING
2005 #define CRYPTO_DRBG_CTR_STRING ""
2007 MODULE_LICENSE("GPL");
2008 MODULE_AUTHOR("Stephan Mueller <smueller@chronox.de>");
2009 MODULE_DESCRIPTION("NIST SP800-90A Deterministic Random Bit Generator (DRBG) "
2010 "using following cores: "
2011 CRYPTO_DRBG_HASH_STRING
2012 CRYPTO_DRBG_HMAC_STRING
2013 CRYPTO_DRBG_CTR_STRING
);