2 * DRBG: Deterministic Random Bits Generator
3 * Based on NIST Recommended DRBG from NIST SP800-90A with the following
5 * * CTR DRBG with DF with AES-128, AES-192, AES-256 cores
6 * * Hash DRBG with DF with SHA-1, SHA-256, SHA-384, SHA-512 cores
7 * * HMAC DRBG with DF with SHA-1, SHA-256, SHA-384, SHA-512 cores
8 * * with and without prediction resistance
10 * Copyright Stephan Mueller <smueller@chronox.de>, 2014
12 * Redistribution and use in source and binary forms, with or without
13 * modification, are permitted provided that the following conditions
15 * 1. Redistributions of source code must retain the above copyright
16 * notice, and the entire permission notice in its entirety,
17 * including the disclaimer of warranties.
18 * 2. Redistributions in binary form must reproduce the above copyright
19 * notice, this list of conditions and the following disclaimer in the
20 * documentation and/or other materials provided with the distribution.
21 * 3. The name of the author may not be used to endorse or promote
22 * products derived from this software without specific prior
25 * ALTERNATIVELY, this product may be distributed under the terms of
26 * the GNU General Public License, in which case the provisions of the GPL are
27 * required INSTEAD OF the above restrictions. (This clause is
28 * necessary due to a potential bad interaction between the GPL and
29 * the restrictions contained in a BSD-style copyright.)
31 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
32 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
33 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, ALL OF
34 * WHICH ARE HEREBY DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE
35 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
36 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
37 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
38 * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
39 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
40 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
41 * USE OF THIS SOFTWARE, EVEN IF NOT ADVISED OF THE POSSIBILITY OF SUCH
46 * The SP 800-90A DRBG allows the user to specify a personalization string
47 * for initialization as well as an additional information string for each
48 * random number request. The following code fragments show how a caller
49 * uses the kernel crypto API to use the full functionality of the DRBG.
51 * Usage without any additional data
52 * ---------------------------------
53 * struct crypto_rng *drng;
57 * drng = crypto_alloc_rng(drng_name, 0, 0);
58 * err = crypto_rng_get_bytes(drng, &data, DATALEN);
59 * crypto_free_rng(drng);
62 * Usage with personalization string during initialization
63 * -------------------------------------------------------
64 * struct crypto_rng *drng;
67 * struct drbg_string pers;
68 * char personalization[11] = "some-string";
70 * drbg_string_fill(&pers, personalization, strlen(personalization));
71 * drng = crypto_alloc_rng(drng_name, 0, 0);
72 * // The reset completely re-initializes the DRBG with the provided
73 * // personalization string
74 * err = crypto_rng_reset(drng, &personalization, strlen(personalization));
75 * err = crypto_rng_get_bytes(drng, &data, DATALEN);
76 * crypto_free_rng(drng);
79 * Usage with additional information string during random number request
80 * ---------------------------------------------------------------------
81 * struct crypto_rng *drng;
84 * char addtl_string[11] = "some-string";
85 * string drbg_string addtl;
87 * drbg_string_fill(&addtl, addtl_string, strlen(addtl_string));
88 * drng = crypto_alloc_rng(drng_name, 0, 0);
89 * // The following call is a wrapper to crypto_rng_get_bytes() and returns
90 * // the same error codes.
91 * err = crypto_drbg_get_bytes_addtl(drng, &data, DATALEN, &addtl);
92 * crypto_free_rng(drng);
95 * Usage with personalization and additional information strings
96 * -------------------------------------------------------------
97 * Just mix both scenarios above.
100 #include <crypto/drbg.h>
101 #include <linux/string.h>
103 /***************************************************************
104 * Backend cipher definitions available to DRBG
105 ***************************************************************/
108 * The order of the DRBG definitions here matter: every DRBG is registered
109 * as stdrng. Each DRBG receives an increasing cra_priority values the later
110 * they are defined in this array (see drbg_fill_array).
112 * HMAC DRBGs are favored over Hash DRBGs over CTR DRBGs, and
113 * the SHA256 / AES 256 over other ciphers. Thus, the favored
114 * DRBGs are the latest entries in this array.
116 static const struct drbg_core drbg_cores
[] = {
117 #ifdef CONFIG_CRYPTO_DRBG_CTR
119 .flags
= DRBG_CTR
| DRBG_STRENGTH128
,
120 .statelen
= 32, /* 256 bits as defined in 10.2.1 */
121 .blocklen_bytes
= 16,
122 .cra_name
= "ctr_aes128",
123 .backend_cra_name
= "ecb(aes)",
125 .flags
= DRBG_CTR
| DRBG_STRENGTH192
,
126 .statelen
= 40, /* 320 bits as defined in 10.2.1 */
127 .blocklen_bytes
= 16,
128 .cra_name
= "ctr_aes192",
129 .backend_cra_name
= "ecb(aes)",
131 .flags
= DRBG_CTR
| DRBG_STRENGTH256
,
132 .statelen
= 48, /* 384 bits as defined in 10.2.1 */
133 .blocklen_bytes
= 16,
134 .cra_name
= "ctr_aes256",
135 .backend_cra_name
= "ecb(aes)",
137 #endif /* CONFIG_CRYPTO_DRBG_CTR */
138 #ifdef CONFIG_CRYPTO_DRBG_HASH
140 .flags
= DRBG_HASH
| DRBG_STRENGTH128
,
141 .statelen
= 55, /* 440 bits */
142 .blocklen_bytes
= 20,
144 .backend_cra_name
= "sha1",
146 .flags
= DRBG_HASH
| DRBG_STRENGTH256
,
147 .statelen
= 111, /* 888 bits */
148 .blocklen_bytes
= 48,
149 .cra_name
= "sha384",
150 .backend_cra_name
= "sha384",
152 .flags
= DRBG_HASH
| DRBG_STRENGTH256
,
153 .statelen
= 111, /* 888 bits */
154 .blocklen_bytes
= 64,
155 .cra_name
= "sha512",
156 .backend_cra_name
= "sha512",
158 .flags
= DRBG_HASH
| DRBG_STRENGTH256
,
159 .statelen
= 55, /* 440 bits */
160 .blocklen_bytes
= 32,
161 .cra_name
= "sha256",
162 .backend_cra_name
= "sha256",
164 #endif /* CONFIG_CRYPTO_DRBG_HASH */
165 #ifdef CONFIG_CRYPTO_DRBG_HMAC
167 .flags
= DRBG_HMAC
| DRBG_STRENGTH128
,
168 .statelen
= 20, /* block length of cipher */
169 .blocklen_bytes
= 20,
170 .cra_name
= "hmac_sha1",
171 .backend_cra_name
= "hmac(sha1)",
173 .flags
= DRBG_HMAC
| DRBG_STRENGTH256
,
174 .statelen
= 48, /* block length of cipher */
175 .blocklen_bytes
= 48,
176 .cra_name
= "hmac_sha384",
177 .backend_cra_name
= "hmac(sha384)",
179 .flags
= DRBG_HMAC
| DRBG_STRENGTH256
,
180 .statelen
= 64, /* block length of cipher */
181 .blocklen_bytes
= 64,
182 .cra_name
= "hmac_sha512",
183 .backend_cra_name
= "hmac(sha512)",
185 .flags
= DRBG_HMAC
| DRBG_STRENGTH256
,
186 .statelen
= 32, /* block length of cipher */
187 .blocklen_bytes
= 32,
188 .cra_name
= "hmac_sha256",
189 .backend_cra_name
= "hmac(sha256)",
191 #endif /* CONFIG_CRYPTO_DRBG_HMAC */
194 /******************************************************************
195 * Generic helper functions
196 ******************************************************************/
199 * Return strength of DRBG according to SP800-90A section 8.4
201 * @flags DRBG flags reference
203 * Return: normalized strength in *bytes* value or 32 as default
204 * to counter programming errors
206 static inline unsigned short drbg_sec_strength(drbg_flag_t flags
)
208 switch (flags
& DRBG_STRENGTH_MASK
) {
209 case DRBG_STRENGTH128
:
211 case DRBG_STRENGTH192
:
213 case DRBG_STRENGTH256
:
221 * FIPS 140-2 continuous self test
222 * The test is performed on the result of one round of the output
223 * function. Thus, the function implicitly knows the size of the
227 * @buf output buffer of random data to be checked
233 static bool drbg_fips_continuous_test(struct drbg_state
*drbg
,
234 const unsigned char *buf
)
236 #ifdef CONFIG_CRYPTO_FIPS
238 /* skip test if we test the overall system */
241 /* only perform test in FIPS mode */
242 if (0 == fips_enabled
)
244 if (!drbg
->fips_primed
) {
245 /* Priming of FIPS test */
246 memcpy(drbg
->prev
, buf
, drbg_blocklen(drbg
));
247 drbg
->fips_primed
= true;
248 /* return false due to priming, i.e. another round is needed */
251 ret
= memcmp(drbg
->prev
, buf
, drbg_blocklen(drbg
));
253 panic("DRBG continuous self test failed\n");
254 memcpy(drbg
->prev
, buf
, drbg_blocklen(drbg
));
255 /* the test shall pass when the two compared values are not equal */
259 #endif /* CONFIG_CRYPTO_FIPS */
263 * Convert an integer into a byte representation of this integer.
264 * The byte representation is big-endian
266 * @val value to be converted
267 * @buf buffer holding the converted integer -- caller must ensure that
268 * buffer size is at least 32 bit
270 #if (defined(CONFIG_CRYPTO_DRBG_HASH) || defined(CONFIG_CRYPTO_DRBG_CTR))
271 static inline void drbg_cpu_to_be32(__u32 val
, unsigned char *buf
)
276 struct s
*conversion
= (struct s
*) buf
;
278 conversion
->conv
= cpu_to_be32(val
);
280 #endif /* defined(CONFIG_CRYPTO_DRBG_HASH) || defined(CONFIG_CRYPTO_DRBG_CTR) */
282 /******************************************************************
283 * CTR DRBG callback functions
284 ******************************************************************/
286 #ifdef CONFIG_CRYPTO_DRBG_CTR
287 #define CRYPTO_DRBG_CTR_STRING "CTR "
288 MODULE_ALIAS_CRYPTO("drbg_pr_ctr_aes256");
289 MODULE_ALIAS_CRYPTO("drbg_nopr_ctr_aes256");
290 MODULE_ALIAS_CRYPTO("drbg_pr_ctr_aes192");
291 MODULE_ALIAS_CRYPTO("drbg_nopr_ctr_aes192");
292 MODULE_ALIAS_CRYPTO("drbg_pr_ctr_aes128");
293 MODULE_ALIAS_CRYPTO("drbg_nopr_ctr_aes128");
295 static int drbg_kcapi_sym(struct drbg_state
*drbg
, const unsigned char *key
,
296 unsigned char *outval
, const struct drbg_string
*in
);
297 static int drbg_init_sym_kernel(struct drbg_state
*drbg
);
298 static int drbg_fini_sym_kernel(struct drbg_state
*drbg
);
300 /* BCC function for CTR DRBG as defined in 10.4.3 */
301 static int drbg_ctr_bcc(struct drbg_state
*drbg
,
302 unsigned char *out
, const unsigned char *key
,
303 struct list_head
*in
)
306 struct drbg_string
*curr
= NULL
;
307 struct drbg_string data
;
310 drbg_string_fill(&data
, out
, drbg_blocklen(drbg
));
313 memset(out
, 0, drbg_blocklen(drbg
));
315 /* 10.4.3 step 2 / 4 */
316 list_for_each_entry(curr
, in
, list
) {
317 const unsigned char *pos
= curr
->buf
;
318 size_t len
= curr
->len
;
319 /* 10.4.3 step 4.1 */
321 /* 10.4.3 step 4.2 */
322 if (drbg_blocklen(drbg
) == cnt
) {
324 ret
= drbg_kcapi_sym(drbg
, key
, out
, &data
);
334 /* 10.4.3 step 4.2 for last block */
336 ret
= drbg_kcapi_sym(drbg
, key
, out
, &data
);
342 * scratchpad usage: drbg_ctr_update is interlinked with drbg_ctr_df
343 * (and drbg_ctr_bcc, but this function does not need any temporary buffers),
344 * the scratchpad is used as follows:
347 * start: drbg->scratchpad
348 * length: drbg_statelen(drbg) + drbg_blocklen(drbg)
349 * note: the cipher writing into this variable works
350 * blocklen-wise. Now, when the statelen is not a multiple
351 * of blocklen, the generateion loop below "spills over"
352 * by at most blocklen. Thus, we need to give sufficient
355 * start: drbg->scratchpad +
356 * drbg_statelen(drbg) + drbg_blocklen(drbg)
357 * length: drbg_statelen(drbg)
361 * start: df_data + drbg_statelen(drbg)
362 * length: drbg_blocklen(drbg)
364 * start: pad + drbg_blocklen(drbg)
365 * length: drbg_blocklen(drbg)
367 * start: iv + drbg_blocklen(drbg)
368 * length: drbg_satelen(drbg) + drbg_blocklen(drbg)
369 * note: temp is the buffer that the BCC function operates
370 * on. BCC operates blockwise. drbg_statelen(drbg)
371 * is sufficient when the DRBG state length is a multiple
372 * of the block size. For AES192 (and maybe other ciphers)
373 * this is not correct and the length for temp is
374 * insufficient (yes, that also means for such ciphers,
375 * the final output of all BCC rounds are truncated).
376 * Therefore, add drbg_blocklen(drbg) to cover all
380 /* Derivation Function for CTR DRBG as defined in 10.4.2 */
381 static int drbg_ctr_df(struct drbg_state
*drbg
,
382 unsigned char *df_data
, size_t bytes_to_return
,
383 struct list_head
*seedlist
)
386 unsigned char L_N
[8];
388 struct drbg_string S1
, S2
, S4
, cipherin
;
390 unsigned char *pad
= df_data
+ drbg_statelen(drbg
);
391 unsigned char *iv
= pad
+ drbg_blocklen(drbg
);
392 unsigned char *temp
= iv
+ drbg_blocklen(drbg
);
394 unsigned int templen
= 0;
398 const unsigned char *K
= (unsigned char *)
399 "\x00\x01\x02\x03\x04\x05\x06\x07"
400 "\x08\x09\x0a\x0b\x0c\x0d\x0e\x0f"
401 "\x10\x11\x12\x13\x14\x15\x16\x17"
402 "\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f";
404 size_t generated_len
= 0;
406 struct drbg_string
*seed
= NULL
;
408 memset(pad
, 0, drbg_blocklen(drbg
));
409 memset(iv
, 0, drbg_blocklen(drbg
));
410 memset(temp
, 0, drbg_statelen(drbg
));
412 /* 10.4.2 step 1 is implicit as we work byte-wise */
415 if ((512/8) < bytes_to_return
)
418 /* 10.4.2 step 2 -- calculate the entire length of all input data */
419 list_for_each_entry(seed
, seedlist
, list
)
420 inputlen
+= seed
->len
;
421 drbg_cpu_to_be32(inputlen
, &L_N
[0]);
424 drbg_cpu_to_be32(bytes_to_return
, &L_N
[4]);
426 /* 10.4.2 step 5: length is L_N, input_string, one byte, padding */
427 padlen
= (inputlen
+ sizeof(L_N
) + 1) % (drbg_blocklen(drbg
));
428 /* wrap the padlen appropriately */
430 padlen
= drbg_blocklen(drbg
) - padlen
;
432 * pad / padlen contains the 0x80 byte and the following zero bytes.
433 * As the calculated padlen value only covers the number of zero
434 * bytes, this value has to be incremented by one for the 0x80 byte.
439 /* 10.4.2 step 4 -- first fill the linked list and then order it */
440 drbg_string_fill(&S1
, iv
, drbg_blocklen(drbg
));
441 list_add_tail(&S1
.list
, &bcc_list
);
442 drbg_string_fill(&S2
, L_N
, sizeof(L_N
));
443 list_add_tail(&S2
.list
, &bcc_list
);
444 list_splice_tail(seedlist
, &bcc_list
);
445 drbg_string_fill(&S4
, pad
, padlen
);
446 list_add_tail(&S4
.list
, &bcc_list
);
449 while (templen
< (drbg_keylen(drbg
) + (drbg_blocklen(drbg
)))) {
451 * 10.4.2 step 9.1 - the padding is implicit as the buffer
452 * holds zeros after allocation -- even the increment of i
453 * is irrelevant as the increment remains within length of i
455 drbg_cpu_to_be32(i
, iv
);
456 /* 10.4.2 step 9.2 -- BCC and concatenation with temp */
457 ret
= drbg_ctr_bcc(drbg
, temp
+ templen
, K
, &bcc_list
);
460 /* 10.4.2 step 9.3 */
462 templen
+= drbg_blocklen(drbg
);
466 X
= temp
+ (drbg_keylen(drbg
));
467 drbg_string_fill(&cipherin
, X
, drbg_blocklen(drbg
));
469 /* 10.4.2 step 12: overwriting of outval is implemented in next step */
472 while (generated_len
< bytes_to_return
) {
475 * 10.4.2 step 13.1: the truncation of the key length is
476 * implicit as the key is only drbg_blocklen in size based on
477 * the implementation of the cipher function callback
479 ret
= drbg_kcapi_sym(drbg
, temp
, X
, &cipherin
);
482 blocklen
= (drbg_blocklen(drbg
) <
483 (bytes_to_return
- generated_len
)) ?
484 drbg_blocklen(drbg
) :
485 (bytes_to_return
- generated_len
);
486 /* 10.4.2 step 13.2 and 14 */
487 memcpy(df_data
+ generated_len
, X
, blocklen
);
488 generated_len
+= blocklen
;
494 memzero_explicit(iv
, drbg_blocklen(drbg
));
495 memzero_explicit(temp
, drbg_statelen(drbg
));
496 memzero_explicit(pad
, drbg_blocklen(drbg
));
501 * update function of CTR DRBG as defined in 10.2.1.2
503 * The reseed variable has an enhanced meaning compared to the update
504 * functions of the other DRBGs as follows:
505 * 0 => initial seed from initialization
506 * 1 => reseed via drbg_seed
507 * 2 => first invocation from drbg_ctr_update when addtl is present. In
508 * this case, the df_data scratchpad is not deleted so that it is
509 * available for another calls to prevent calling the DF function
511 * 3 => second invocation from drbg_ctr_update. When the update function
512 * was called with addtl, the df_data memory already contains the
513 * DFed addtl information and we do not need to call DF again.
515 static int drbg_ctr_update(struct drbg_state
*drbg
, struct list_head
*seed
,
519 /* 10.2.1.2 step 1 */
520 unsigned char *temp
= drbg
->scratchpad
;
521 unsigned char *df_data
= drbg
->scratchpad
+ drbg_statelen(drbg
) +
523 unsigned char *temp_p
, *df_data_p
; /* pointer to iterate over buffers */
524 unsigned int len
= 0;
525 struct drbg_string cipherin
;
527 memset(temp
, 0, drbg_statelen(drbg
) + drbg_blocklen(drbg
));
529 memset(df_data
, 0, drbg_statelen(drbg
));
531 /* 10.2.1.3.2 step 2 and 10.2.1.4.2 step 2 */
533 ret
= drbg_ctr_df(drbg
, df_data
, drbg_statelen(drbg
), seed
);
538 drbg_string_fill(&cipherin
, drbg
->V
, drbg_blocklen(drbg
));
540 * 10.2.1.3.2 steps 2 and 3 are already covered as the allocation
541 * zeroizes all memory during initialization
543 while (len
< (drbg_statelen(drbg
))) {
544 /* 10.2.1.2 step 2.1 */
545 crypto_inc(drbg
->V
, drbg_blocklen(drbg
));
547 * 10.2.1.2 step 2.2 */
548 ret
= drbg_kcapi_sym(drbg
, drbg
->C
, temp
+ len
, &cipherin
);
551 /* 10.2.1.2 step 2.3 and 3 */
552 len
+= drbg_blocklen(drbg
);
555 /* 10.2.1.2 step 4 */
558 for (len
= 0; len
< drbg_statelen(drbg
); len
++) {
559 *temp_p
^= *df_data_p
;
560 df_data_p
++; temp_p
++;
563 /* 10.2.1.2 step 5 */
564 memcpy(drbg
->C
, temp
, drbg_keylen(drbg
));
565 /* 10.2.1.2 step 6 */
566 memcpy(drbg
->V
, temp
+ drbg_keylen(drbg
), drbg_blocklen(drbg
));
570 memzero_explicit(temp
, drbg_statelen(drbg
) + drbg_blocklen(drbg
));
572 memzero_explicit(df_data
, drbg_statelen(drbg
));
577 * scratchpad use: drbg_ctr_update is called independently from
578 * drbg_ctr_extract_bytes. Therefore, the scratchpad is reused
580 /* Generate function of CTR DRBG as defined in 10.2.1.5.2 */
581 static int drbg_ctr_generate(struct drbg_state
*drbg
,
582 unsigned char *buf
, unsigned int buflen
,
583 struct list_head
*addtl
)
587 struct drbg_string data
;
589 memset(drbg
->scratchpad
, 0, drbg_blocklen(drbg
));
591 /* 10.2.1.5.2 step 2 */
592 if (addtl
&& !list_empty(addtl
)) {
593 ret
= drbg_ctr_update(drbg
, addtl
, 2);
598 /* 10.2.1.5.2 step 4.1 */
599 crypto_inc(drbg
->V
, drbg_blocklen(drbg
));
600 drbg_string_fill(&data
, drbg
->V
, drbg_blocklen(drbg
));
601 while (len
< buflen
) {
603 /* 10.2.1.5.2 step 4.2 */
604 ret
= drbg_kcapi_sym(drbg
, drbg
->C
, drbg
->scratchpad
, &data
);
609 outlen
= (drbg_blocklen(drbg
) < (buflen
- len
)) ?
610 drbg_blocklen(drbg
) : (buflen
- len
);
611 if (!drbg_fips_continuous_test(drbg
, drbg
->scratchpad
)) {
612 /* 10.2.1.5.2 step 6 */
613 crypto_inc(drbg
->V
, drbg_blocklen(drbg
));
616 /* 10.2.1.5.2 step 4.3 */
617 memcpy(buf
+ len
, drbg
->scratchpad
, outlen
);
619 /* 10.2.1.5.2 step 6 */
621 crypto_inc(drbg
->V
, drbg_blocklen(drbg
));
624 /* 10.2.1.5.2 step 6 */
625 ret
= drbg_ctr_update(drbg
, NULL
, 3);
630 memzero_explicit(drbg
->scratchpad
, drbg_blocklen(drbg
));
634 static struct drbg_state_ops drbg_ctr_ops
= {
635 .update
= drbg_ctr_update
,
636 .generate
= drbg_ctr_generate
,
637 .crypto_init
= drbg_init_sym_kernel
,
638 .crypto_fini
= drbg_fini_sym_kernel
,
640 #endif /* CONFIG_CRYPTO_DRBG_CTR */
642 /******************************************************************
643 * HMAC DRBG callback functions
644 ******************************************************************/
646 #if defined(CONFIG_CRYPTO_DRBG_HASH) || defined(CONFIG_CRYPTO_DRBG_HMAC)
647 static int drbg_kcapi_hash(struct drbg_state
*drbg
, const unsigned char *key
,
648 unsigned char *outval
, const struct list_head
*in
);
649 static int drbg_init_hash_kernel(struct drbg_state
*drbg
);
650 static int drbg_fini_hash_kernel(struct drbg_state
*drbg
);
651 #endif /* (CONFIG_CRYPTO_DRBG_HASH || CONFIG_CRYPTO_DRBG_HMAC) */
653 #ifdef CONFIG_CRYPTO_DRBG_HMAC
654 #define CRYPTO_DRBG_HMAC_STRING "HMAC "
655 MODULE_ALIAS_CRYPTO("drbg_pr_hmac_sha512");
656 MODULE_ALIAS_CRYPTO("drbg_nopr_hmac_sha512");
657 MODULE_ALIAS_CRYPTO("drbg_pr_hmac_sha384");
658 MODULE_ALIAS_CRYPTO("drbg_nopr_hmac_sha384");
659 MODULE_ALIAS_CRYPTO("drbg_pr_hmac_sha256");
660 MODULE_ALIAS_CRYPTO("drbg_nopr_hmac_sha256");
661 MODULE_ALIAS_CRYPTO("drbg_pr_hmac_sha1");
662 MODULE_ALIAS_CRYPTO("drbg_nopr_hmac_sha1");
664 /* update function of HMAC DRBG as defined in 10.1.2.2 */
665 static int drbg_hmac_update(struct drbg_state
*drbg
, struct list_head
*seed
,
670 struct drbg_string seed1
, seed2
, vdata
;
672 LIST_HEAD(vdatalist
);
675 /* 10.1.2.3 step 2 -- memset(0) of C is implicit with kzalloc */
676 memset(drbg
->V
, 1, drbg_statelen(drbg
));
678 drbg_string_fill(&seed1
, drbg
->V
, drbg_statelen(drbg
));
679 list_add_tail(&seed1
.list
, &seedlist
);
680 /* buffer of seed2 will be filled in for loop below with one byte */
681 drbg_string_fill(&seed2
, NULL
, 1);
682 list_add_tail(&seed2
.list
, &seedlist
);
683 /* input data of seed is allowed to be NULL at this point */
685 list_splice_tail(seed
, &seedlist
);
687 drbg_string_fill(&vdata
, drbg
->V
, drbg_statelen(drbg
));
688 list_add_tail(&vdata
.list
, &vdatalist
);
689 for (i
= 2; 0 < i
; i
--) {
690 /* first round uses 0x0, second 0x1 */
691 unsigned char prefix
= DRBG_PREFIX0
;
693 prefix
= DRBG_PREFIX1
;
694 /* 10.1.2.2 step 1 and 4 -- concatenation and HMAC for key */
696 ret
= drbg_kcapi_hash(drbg
, drbg
->C
, drbg
->C
, &seedlist
);
700 /* 10.1.2.2 step 2 and 5 -- HMAC for V */
701 ret
= drbg_kcapi_hash(drbg
, drbg
->C
, drbg
->V
, &vdatalist
);
705 /* 10.1.2.2 step 3 */
713 /* generate function of HMAC DRBG as defined in 10.1.2.5 */
714 static int drbg_hmac_generate(struct drbg_state
*drbg
,
717 struct list_head
*addtl
)
721 struct drbg_string data
;
724 /* 10.1.2.5 step 2 */
725 if (addtl
&& !list_empty(addtl
)) {
726 ret
= drbg_hmac_update(drbg
, addtl
, 1);
731 drbg_string_fill(&data
, drbg
->V
, drbg_statelen(drbg
));
732 list_add_tail(&data
.list
, &datalist
);
733 while (len
< buflen
) {
734 unsigned int outlen
= 0;
735 /* 10.1.2.5 step 4.1 */
736 ret
= drbg_kcapi_hash(drbg
, drbg
->C
, drbg
->V
, &datalist
);
739 outlen
= (drbg_blocklen(drbg
) < (buflen
- len
)) ?
740 drbg_blocklen(drbg
) : (buflen
- len
);
741 if (!drbg_fips_continuous_test(drbg
, drbg
->V
))
744 /* 10.1.2.5 step 4.2 */
745 memcpy(buf
+ len
, drbg
->V
, outlen
);
749 /* 10.1.2.5 step 6 */
750 if (addtl
&& !list_empty(addtl
))
751 ret
= drbg_hmac_update(drbg
, addtl
, 1);
753 ret
= drbg_hmac_update(drbg
, NULL
, 1);
760 static struct drbg_state_ops drbg_hmac_ops
= {
761 .update
= drbg_hmac_update
,
762 .generate
= drbg_hmac_generate
,
763 .crypto_init
= drbg_init_hash_kernel
,
764 .crypto_fini
= drbg_fini_hash_kernel
,
767 #endif /* CONFIG_CRYPTO_DRBG_HMAC */
769 /******************************************************************
770 * Hash DRBG callback functions
771 ******************************************************************/
773 #ifdef CONFIG_CRYPTO_DRBG_HASH
774 #define CRYPTO_DRBG_HASH_STRING "HASH "
775 MODULE_ALIAS_CRYPTO("drbg_pr_sha512");
776 MODULE_ALIAS_CRYPTO("drbg_nopr_sha512");
777 MODULE_ALIAS_CRYPTO("drbg_pr_sha384");
778 MODULE_ALIAS_CRYPTO("drbg_nopr_sha384");
779 MODULE_ALIAS_CRYPTO("drbg_pr_sha256");
780 MODULE_ALIAS_CRYPTO("drbg_nopr_sha256");
781 MODULE_ALIAS_CRYPTO("drbg_pr_sha1");
782 MODULE_ALIAS_CRYPTO("drbg_nopr_sha1");
787 * @dst buffer to increment
790 static inline void drbg_add_buf(unsigned char *dst
, size_t dstlen
,
791 const unsigned char *add
, size_t addlen
)
793 /* implied: dstlen > addlen */
794 unsigned char *dstptr
;
795 const unsigned char *addptr
;
796 unsigned int remainder
= 0;
799 dstptr
= dst
+ (dstlen
-1);
800 addptr
= add
+ (addlen
-1);
802 remainder
+= *dstptr
+ *addptr
;
803 *dstptr
= remainder
& 0xff;
805 len
--; dstptr
--; addptr
--;
807 len
= dstlen
- addlen
;
808 while (len
&& remainder
> 0) {
809 remainder
= *dstptr
+ 1;
810 *dstptr
= remainder
& 0xff;
817 * scratchpad usage: as drbg_hash_update and drbg_hash_df are used
818 * interlinked, the scratchpad is used as follows:
820 * start: drbg->scratchpad
821 * length: drbg_statelen(drbg)
823 * start: drbg->scratchpad + drbg_statelen(drbg)
824 * length: drbg_blocklen(drbg)
826 * drbg_hash_process_addtl uses the scratchpad, but fully completes
827 * before either of the functions mentioned before are invoked. Therefore,
828 * drbg_hash_process_addtl does not need to be specifically considered.
831 /* Derivation Function for Hash DRBG as defined in 10.4.1 */
832 static int drbg_hash_df(struct drbg_state
*drbg
,
833 unsigned char *outval
, size_t outlen
,
834 struct list_head
*entropylist
)
838 unsigned char input
[5];
839 unsigned char *tmp
= drbg
->scratchpad
+ drbg_statelen(drbg
);
840 struct drbg_string data
;
842 memset(tmp
, 0, drbg_blocklen(drbg
));
846 drbg_cpu_to_be32((outlen
* 8), &input
[1]);
848 /* 10.4.1 step 4.1 -- concatenation of data for input into hash */
849 drbg_string_fill(&data
, input
, 5);
850 list_add(&data
.list
, entropylist
);
853 while (len
< outlen
) {
855 /* 10.4.1 step 4.1 */
856 ret
= drbg_kcapi_hash(drbg
, NULL
, tmp
, entropylist
);
859 /* 10.4.1 step 4.2 */
861 blocklen
= (drbg_blocklen(drbg
) < (outlen
- len
)) ?
862 drbg_blocklen(drbg
) : (outlen
- len
);
863 memcpy(outval
+ len
, tmp
, blocklen
);
868 memzero_explicit(tmp
, drbg_blocklen(drbg
));
872 /* update function for Hash DRBG as defined in 10.1.1.2 / 10.1.1.3 */
873 static int drbg_hash_update(struct drbg_state
*drbg
, struct list_head
*seed
,
877 struct drbg_string data1
, data2
;
879 LIST_HEAD(datalist2
);
880 unsigned char *V
= drbg
->scratchpad
;
881 unsigned char prefix
= DRBG_PREFIX1
;
883 memset(drbg
->scratchpad
, 0, drbg_statelen(drbg
));
888 /* 10.1.1.3 step 1 */
889 memcpy(V
, drbg
->V
, drbg_statelen(drbg
));
890 drbg_string_fill(&data1
, &prefix
, 1);
891 list_add_tail(&data1
.list
, &datalist
);
892 drbg_string_fill(&data2
, V
, drbg_statelen(drbg
));
893 list_add_tail(&data2
.list
, &datalist
);
895 list_splice_tail(seed
, &datalist
);
897 /* 10.1.1.2 / 10.1.1.3 step 2 and 3 */
898 ret
= drbg_hash_df(drbg
, drbg
->V
, drbg_statelen(drbg
), &datalist
);
902 /* 10.1.1.2 / 10.1.1.3 step 4 */
903 prefix
= DRBG_PREFIX0
;
904 drbg_string_fill(&data1
, &prefix
, 1);
905 list_add_tail(&data1
.list
, &datalist2
);
906 drbg_string_fill(&data2
, drbg
->V
, drbg_statelen(drbg
));
907 list_add_tail(&data2
.list
, &datalist2
);
908 /* 10.1.1.2 / 10.1.1.3 step 4 */
909 ret
= drbg_hash_df(drbg
, drbg
->C
, drbg_statelen(drbg
), &datalist2
);
912 memzero_explicit(drbg
->scratchpad
, drbg_statelen(drbg
));
916 /* processing of additional information string for Hash DRBG */
917 static int drbg_hash_process_addtl(struct drbg_state
*drbg
,
918 struct list_head
*addtl
)
921 struct drbg_string data1
, data2
;
923 unsigned char prefix
= DRBG_PREFIX2
;
925 /* this is value w as per documentation */
926 memset(drbg
->scratchpad
, 0, drbg_blocklen(drbg
));
928 /* 10.1.1.4 step 2 */
929 if (!addtl
|| list_empty(addtl
))
932 /* 10.1.1.4 step 2a */
933 drbg_string_fill(&data1
, &prefix
, 1);
934 drbg_string_fill(&data2
, drbg
->V
, drbg_statelen(drbg
));
935 list_add_tail(&data1
.list
, &datalist
);
936 list_add_tail(&data2
.list
, &datalist
);
937 list_splice_tail(addtl
, &datalist
);
938 ret
= drbg_kcapi_hash(drbg
, NULL
, drbg
->scratchpad
, &datalist
);
942 /* 10.1.1.4 step 2b */
943 drbg_add_buf(drbg
->V
, drbg_statelen(drbg
),
944 drbg
->scratchpad
, drbg_blocklen(drbg
));
947 memzero_explicit(drbg
->scratchpad
, drbg_blocklen(drbg
));
951 /* Hashgen defined in 10.1.1.4 */
952 static int drbg_hash_hashgen(struct drbg_state
*drbg
,
958 unsigned char *src
= drbg
->scratchpad
;
959 unsigned char *dst
= drbg
->scratchpad
+ drbg_statelen(drbg
);
960 struct drbg_string data
;
963 memset(src
, 0, drbg_statelen(drbg
));
964 memset(dst
, 0, drbg_blocklen(drbg
));
966 /* 10.1.1.4 step hashgen 2 */
967 memcpy(src
, drbg
->V
, drbg_statelen(drbg
));
969 drbg_string_fill(&data
, src
, drbg_statelen(drbg
));
970 list_add_tail(&data
.list
, &datalist
);
971 while (len
< buflen
) {
972 unsigned int outlen
= 0;
973 /* 10.1.1.4 step hashgen 4.1 */
974 ret
= drbg_kcapi_hash(drbg
, NULL
, dst
, &datalist
);
979 outlen
= (drbg_blocklen(drbg
) < (buflen
- len
)) ?
980 drbg_blocklen(drbg
) : (buflen
- len
);
981 if (!drbg_fips_continuous_test(drbg
, dst
)) {
982 crypto_inc(src
, drbg_statelen(drbg
));
985 /* 10.1.1.4 step hashgen 4.2 */
986 memcpy(buf
+ len
, dst
, outlen
);
988 /* 10.1.1.4 hashgen step 4.3 */
990 crypto_inc(src
, drbg_statelen(drbg
));
994 memzero_explicit(drbg
->scratchpad
,
995 (drbg_statelen(drbg
) + drbg_blocklen(drbg
)));
999 /* generate function for Hash DRBG as defined in 10.1.1.4 */
1000 static int drbg_hash_generate(struct drbg_state
*drbg
,
1001 unsigned char *buf
, unsigned int buflen
,
1002 struct list_head
*addtl
)
1007 unsigned char req
[8];
1010 unsigned char prefix
= DRBG_PREFIX3
;
1011 struct drbg_string data1
, data2
;
1012 LIST_HEAD(datalist
);
1014 /* 10.1.1.4 step 2 */
1015 ret
= drbg_hash_process_addtl(drbg
, addtl
);
1018 /* 10.1.1.4 step 3 */
1019 len
= drbg_hash_hashgen(drbg
, buf
, buflen
);
1021 /* this is the value H as documented in 10.1.1.4 */
1022 memset(drbg
->scratchpad
, 0, drbg_blocklen(drbg
));
1023 /* 10.1.1.4 step 4 */
1024 drbg_string_fill(&data1
, &prefix
, 1);
1025 list_add_tail(&data1
.list
, &datalist
);
1026 drbg_string_fill(&data2
, drbg
->V
, drbg_statelen(drbg
));
1027 list_add_tail(&data2
.list
, &datalist
);
1028 ret
= drbg_kcapi_hash(drbg
, NULL
, drbg
->scratchpad
, &datalist
);
1034 /* 10.1.1.4 step 5 */
1035 drbg_add_buf(drbg
->V
, drbg_statelen(drbg
),
1036 drbg
->scratchpad
, drbg_blocklen(drbg
));
1037 drbg_add_buf(drbg
->V
, drbg_statelen(drbg
),
1038 drbg
->C
, drbg_statelen(drbg
));
1039 u
.req_int
= cpu_to_be64(drbg
->reseed_ctr
);
1040 drbg_add_buf(drbg
->V
, drbg_statelen(drbg
), u
.req
, 8);
1043 memzero_explicit(drbg
->scratchpad
, drbg_blocklen(drbg
));
1048 * scratchpad usage: as update and generate are used isolated, both
1049 * can use the scratchpad
1051 static struct drbg_state_ops drbg_hash_ops
= {
1052 .update
= drbg_hash_update
,
1053 .generate
= drbg_hash_generate
,
1054 .crypto_init
= drbg_init_hash_kernel
,
1055 .crypto_fini
= drbg_fini_hash_kernel
,
1057 #endif /* CONFIG_CRYPTO_DRBG_HASH */
1059 /******************************************************************
1060 * Functions common for DRBG implementations
1061 ******************************************************************/
1064 * Seeding or reseeding of the DRBG
1066 * @drbg: DRBG state struct
1067 * @pers: personalization / additional information buffer
1068 * @reseed: 0 for initial seed process, 1 for reseeding
1072 * error value otherwise
1074 static int drbg_seed(struct drbg_state
*drbg
, struct drbg_string
*pers
,
1078 unsigned char *entropy
= NULL
;
1079 size_t entropylen
= 0;
1080 struct drbg_string data1
;
1081 LIST_HEAD(seedlist
);
1083 /* 9.1 / 9.2 / 9.3.1 step 3 */
1084 if (pers
&& pers
->len
> (drbg_max_addtl(drbg
))) {
1085 pr_devel("DRBG: personalization string too long %zu\n",
1090 if (drbg
->test_data
&& drbg
->test_data
->testentropy
) {
1091 drbg_string_fill(&data1
, drbg
->test_data
->testentropy
->buf
,
1092 drbg
->test_data
->testentropy
->len
);
1093 pr_devel("DRBG: using test entropy\n");
1096 * Gather entropy equal to the security strength of the DRBG.
1097 * With a derivation function, a nonce is required in addition
1098 * to the entropy. A nonce must be at least 1/2 of the security
1099 * strength of the DRBG in size. Thus, entropy * nonce is 3/2
1100 * of the strength. The consideration of a nonce is only
1101 * applicable during initial seeding.
1103 entropylen
= drbg_sec_strength(drbg
->core
->flags
);
1107 entropylen
= ((entropylen
+ 1) / 2) * 3;
1108 pr_devel("DRBG: (re)seeding with %zu bytes of entropy\n",
1110 entropy
= kzalloc(entropylen
, GFP_KERNEL
);
1113 get_random_bytes(entropy
, entropylen
);
1114 drbg_string_fill(&data1
, entropy
, entropylen
);
1116 list_add_tail(&data1
.list
, &seedlist
);
1119 * concatenation of entropy with personalization str / addtl input)
1120 * the variable pers is directly handed in by the caller, so check its
1121 * contents whether it is appropriate
1123 if (pers
&& pers
->buf
&& 0 < pers
->len
) {
1124 list_add_tail(&pers
->list
, &seedlist
);
1125 pr_devel("DRBG: using personalization string\n");
1129 memset(drbg
->V
, 0, drbg_statelen(drbg
));
1130 memset(drbg
->C
, 0, drbg_statelen(drbg
));
1133 ret
= drbg
->d_ops
->update(drbg
, &seedlist
, reseed
);
1137 drbg
->seeded
= true;
1138 /* 10.1.1.2 / 10.1.1.3 step 5 */
1139 drbg
->reseed_ctr
= 1;
1146 /* Free all substructures in a DRBG state without the DRBG state structure */
1147 static inline void drbg_dealloc_state(struct drbg_state
*drbg
)
1155 kzfree(drbg
->scratchpad
);
1156 drbg
->scratchpad
= NULL
;
1157 drbg
->reseed_ctr
= 0;
1158 #ifdef CONFIG_CRYPTO_FIPS
1161 drbg
->fips_primed
= false;
1166 * Allocate all sub-structures for a DRBG state.
1167 * The DRBG state structure must already be allocated.
1169 static inline int drbg_alloc_state(struct drbg_state
*drbg
)
1172 unsigned int sb_size
= 0;
1174 drbg
->V
= kmalloc(drbg_statelen(drbg
), GFP_KERNEL
);
1177 drbg
->C
= kmalloc(drbg_statelen(drbg
), GFP_KERNEL
);
1180 #ifdef CONFIG_CRYPTO_FIPS
1181 drbg
->prev
= kmalloc(drbg_blocklen(drbg
), GFP_KERNEL
);
1184 drbg
->fips_primed
= false;
1186 /* scratchpad is only generated for CTR and Hash */
1187 if (drbg
->core
->flags
& DRBG_HMAC
)
1189 else if (drbg
->core
->flags
& DRBG_CTR
)
1190 sb_size
= drbg_statelen(drbg
) + drbg_blocklen(drbg
) + /* temp */
1191 drbg_statelen(drbg
) + /* df_data */
1192 drbg_blocklen(drbg
) + /* pad */
1193 drbg_blocklen(drbg
) + /* iv */
1194 drbg_statelen(drbg
) + drbg_blocklen(drbg
); /* temp */
1196 sb_size
= drbg_statelen(drbg
) + drbg_blocklen(drbg
);
1199 drbg
->scratchpad
= kzalloc(sb_size
, GFP_KERNEL
);
1200 if (!drbg
->scratchpad
)
1203 spin_lock_init(&drbg
->drbg_lock
);
1207 drbg_dealloc_state(drbg
);
1212 * Strategy to avoid holding long term locks: generate a shadow copy of DRBG
1213 * and perform all operations on this shadow copy. After finishing, restore
1214 * the updated state of the shadow copy into original drbg state. This way,
1215 * only the read and write operations of the original drbg state must be
1218 static inline void drbg_copy_drbg(struct drbg_state
*src
,
1219 struct drbg_state
*dst
)
1223 memcpy(dst
->V
, src
->V
, drbg_statelen(src
));
1224 memcpy(dst
->C
, src
->C
, drbg_statelen(src
));
1225 dst
->reseed_ctr
= src
->reseed_ctr
;
1226 dst
->seeded
= src
->seeded
;
1228 #ifdef CONFIG_CRYPTO_FIPS
1229 dst
->fips_primed
= src
->fips_primed
;
1230 memcpy(dst
->prev
, src
->prev
, drbg_blocklen(src
));
1234 * scratchpad is initialized drbg_alloc_state;
1235 * priv_data is initialized with call to crypto_init;
1236 * d_ops and core are set outside, as these parameters are const;
1237 * test_data is set outside to prevent it being copied back.
1241 static int drbg_make_shadow(struct drbg_state
*drbg
, struct drbg_state
**shadow
)
1244 struct drbg_state
*tmp
= NULL
;
1246 tmp
= kzalloc(sizeof(struct drbg_state
), GFP_KERNEL
);
1250 /* read-only data as they are defined as const, no lock needed */
1251 tmp
->core
= drbg
->core
;
1252 tmp
->d_ops
= drbg
->d_ops
;
1254 ret
= drbg_alloc_state(tmp
);
1258 spin_lock_bh(&drbg
->drbg_lock
);
1259 drbg_copy_drbg(drbg
, tmp
);
1260 /* only make a link to the test buffer, as we only read that data */
1261 tmp
->test_data
= drbg
->test_data
;
1262 spin_unlock_bh(&drbg
->drbg_lock
);
1271 static void drbg_restore_shadow(struct drbg_state
*drbg
,
1272 struct drbg_state
**shadow
)
1274 struct drbg_state
*tmp
= *shadow
;
1276 spin_lock_bh(&drbg
->drbg_lock
);
1277 drbg_copy_drbg(tmp
, drbg
);
1278 spin_unlock_bh(&drbg
->drbg_lock
);
1279 drbg_dealloc_state(tmp
);
1284 /*************************************************************************
1285 * DRBG interface functions
1286 *************************************************************************/
1289 * DRBG generate function as required by SP800-90A - this function
1290 * generates random numbers
1292 * @drbg DRBG state handle
1293 * @buf Buffer where to store the random numbers -- the buffer must already
1294 * be pre-allocated by caller
1295 * @buflen Length of output buffer - this value defines the number of random
1296 * bytes pulled from DRBG
1297 * @addtl Additional input that is mixed into state, may be NULL -- note
1298 * the entropy is pulled by the DRBG internally unconditionally
1299 * as defined in SP800-90A. The additional input is mixed into
1300 * the state in addition to the pulled entropy.
1302 * return: generated number of bytes
1304 static int drbg_generate(struct drbg_state
*drbg
,
1305 unsigned char *buf
, unsigned int buflen
,
1306 struct drbg_string
*addtl
)
1309 struct drbg_state
*shadow
= NULL
;
1310 LIST_HEAD(addtllist
);
1311 struct drbg_string timestamp
;
1314 unsigned char char_cycles
[sizeof(cycles_t
)];
1317 if (0 == buflen
|| !buf
) {
1318 pr_devel("DRBG: no output buffer provided\n");
1321 if (addtl
&& NULL
== addtl
->buf
&& 0 < addtl
->len
) {
1322 pr_devel("DRBG: wrong format of additional information\n");
1326 len
= drbg_make_shadow(drbg
, &shadow
);
1328 pr_devel("DRBG: shadow copy cannot be generated\n");
1334 if (buflen
> (drbg_max_request_bytes(shadow
))) {
1335 pr_devel("DRBG: requested random numbers too large %u\n",
1340 /* 9.3.1 step 3 is implicit with the chosen DRBG */
1343 if (addtl
&& addtl
->len
> (drbg_max_addtl(shadow
))) {
1344 pr_devel("DRBG: additional information string too long %zu\n",
1348 /* 9.3.1 step 5 is implicit with the chosen DRBG */
1351 * 9.3.1 step 6 and 9 supplemented by 9.3.2 step c is implemented
1352 * here. The spec is a bit convoluted here, we make it simpler.
1354 if ((drbg_max_requests(shadow
)) < shadow
->reseed_ctr
)
1355 shadow
->seeded
= false;
1357 /* allocate cipher handle */
1358 len
= shadow
->d_ops
->crypto_init(shadow
);
1362 if (shadow
->pr
|| !shadow
->seeded
) {
1363 pr_devel("DRBG: reseeding before generation (prediction "
1364 "resistance: %s, state %s)\n",
1365 drbg
->pr
? "true" : "false",
1366 drbg
->seeded
? "seeded" : "unseeded");
1367 /* 9.3.1 steps 7.1 through 7.3 */
1368 len
= drbg_seed(shadow
, addtl
, true);
1371 /* 9.3.1 step 7.4 */
1376 * Mix the time stamp into the DRBG state if the DRBG is not in
1377 * test mode. If there are two callers invoking the DRBG at the same
1378 * time, i.e. before the first caller merges its shadow state back,
1379 * both callers would obtain the same random number stream without
1380 * changing the state here.
1382 if (!drbg
->test_data
) {
1383 now
.cycles
= random_get_entropy();
1384 drbg_string_fill(×tamp
, now
.char_cycles
, sizeof(cycles_t
));
1385 list_add_tail(×tamp
.list
, &addtllist
);
1387 if (addtl
&& 0 < addtl
->len
)
1388 list_add_tail(&addtl
->list
, &addtllist
);
1389 /* 9.3.1 step 8 and 10 */
1390 len
= shadow
->d_ops
->generate(shadow
, buf
, buflen
, &addtllist
);
1392 /* 10.1.1.4 step 6, 10.1.2.5 step 7, 10.2.1.5.2 step 7 */
1393 shadow
->reseed_ctr
++;
1398 * Section 11.3.3 requires to re-perform self tests after some
1399 * generated random numbers. The chosen value after which self
1400 * test is performed is arbitrary, but it should be reasonable.
1401 * However, we do not perform the self tests because of the following
1402 * reasons: it is mathematically impossible that the initial self tests
1403 * were successfully and the following are not. If the initial would
1404 * pass and the following would not, the kernel integrity is violated.
1405 * In this case, the entire kernel operation is questionable and it
1406 * is unlikely that the integrity violation only affects the
1407 * correct operation of the DRBG.
1409 * Albeit the following code is commented out, it is provided in
1410 * case somebody has a need to implement the test of 11.3.3.
1413 if (shadow
->reseed_ctr
&& !(shadow
->reseed_ctr
% 4096)) {
1415 pr_devel("DRBG: start to perform self test\n");
1416 if (drbg
->core
->flags
& DRBG_HMAC
)
1417 err
= alg_test("drbg_pr_hmac_sha256",
1418 "drbg_pr_hmac_sha256", 0, 0);
1419 else if (drbg
->core
->flags
& DRBG_CTR
)
1420 err
= alg_test("drbg_pr_ctr_aes128",
1421 "drbg_pr_ctr_aes128", 0, 0);
1423 err
= alg_test("drbg_pr_sha256",
1424 "drbg_pr_sha256", 0, 0);
1426 pr_err("DRBG: periodical self test failed\n");
1428 * uninstantiate implies that from now on, only errors
1429 * are returned when reusing this DRBG cipher handle
1431 drbg_uninstantiate(drbg
);
1432 drbg_dealloc_state(shadow
);
1436 pr_devel("DRBG: self test successful\n");
1442 shadow
->d_ops
->crypto_fini(shadow
);
1443 drbg_restore_shadow(drbg
, &shadow
);
1448 * Wrapper around drbg_generate which can pull arbitrary long strings
1449 * from the DRBG without hitting the maximum request limitation.
1451 * Parameters: see drbg_generate
1452 * Return codes: see drbg_generate -- if one drbg_generate request fails,
1453 * the entire drbg_generate_long request fails
1455 static int drbg_generate_long(struct drbg_state
*drbg
,
1456 unsigned char *buf
, unsigned int buflen
,
1457 struct drbg_string
*addtl
)
1460 unsigned int slice
= 0;
1463 unsigned int chunk
= 0;
1464 slice
= ((buflen
- len
) / drbg_max_request_bytes(drbg
));
1465 chunk
= slice
? drbg_max_request_bytes(drbg
) : (buflen
- len
);
1466 tmplen
= drbg_generate(drbg
, buf
+ len
, chunk
, addtl
);
1470 } while (slice
> 0 && (len
< buflen
));
1475 * DRBG instantiation function as required by SP800-90A - this function
1476 * sets up the DRBG handle, performs the initial seeding and all sanity
1477 * checks required by SP800-90A
1479 * @drbg memory of state -- if NULL, new memory is allocated
1480 * @pers Personalization string that is mixed into state, may be NULL -- note
1481 * the entropy is pulled by the DRBG internally unconditionally
1482 * as defined in SP800-90A. The additional input is mixed into
1483 * the state in addition to the pulled entropy.
1484 * @coreref reference to core
1485 * @pr prediction resistance enabled
1489 * error value otherwise
1491 static int drbg_instantiate(struct drbg_state
*drbg
, struct drbg_string
*pers
,
1492 int coreref
, bool pr
)
1496 pr_devel("DRBG: Initializing DRBG core %d with prediction resistance "
1497 "%s\n", coreref
, pr
? "enabled" : "disabled");
1498 drbg
->core
= &drbg_cores
[coreref
];
1500 drbg
->seeded
= false;
1501 switch (drbg
->core
->flags
& DRBG_TYPE_MASK
) {
1502 #ifdef CONFIG_CRYPTO_DRBG_HMAC
1504 drbg
->d_ops
= &drbg_hmac_ops
;
1506 #endif /* CONFIG_CRYPTO_DRBG_HMAC */
1507 #ifdef CONFIG_CRYPTO_DRBG_HASH
1509 drbg
->d_ops
= &drbg_hash_ops
;
1511 #endif /* CONFIG_CRYPTO_DRBG_HASH */
1512 #ifdef CONFIG_CRYPTO_DRBG_CTR
1514 drbg
->d_ops
= &drbg_ctr_ops
;
1516 #endif /* CONFIG_CRYPTO_DRBG_CTR */
1521 /* 9.1 step 1 is implicit with the selected DRBG type */
1524 * 9.1 step 2 is implicit as caller can select prediction resistance
1525 * and the flag is copied into drbg->flags --
1526 * all DRBG types support prediction resistance
1529 /* 9.1 step 4 is implicit in drbg_sec_strength */
1531 ret
= drbg_alloc_state(drbg
);
1536 if (drbg
->d_ops
->crypto_init(drbg
))
1538 ret
= drbg_seed(drbg
, pers
, false);
1539 drbg
->d_ops
->crypto_fini(drbg
);
1546 drbg_dealloc_state(drbg
);
1551 * DRBG uninstantiate function as required by SP800-90A - this function
1552 * frees all buffers and the DRBG handle
1554 * @drbg DRBG state handle
1559 static int drbg_uninstantiate(struct drbg_state
*drbg
)
1561 spin_lock_bh(&drbg
->drbg_lock
);
1562 drbg_dealloc_state(drbg
);
1563 /* no scrubbing of test_data -- this shall survive an uninstantiate */
1564 spin_unlock_bh(&drbg
->drbg_lock
);
1569 * Helper function for setting the test data in the DRBG
1571 * @drbg DRBG state handle
1572 * @test_data test data to sets
1574 static inline void drbg_set_testdata(struct drbg_state
*drbg
,
1575 struct drbg_test_data
*test_data
)
1577 if (!test_data
|| !test_data
->testentropy
)
1579 spin_lock_bh(&drbg
->drbg_lock
);
1580 drbg
->test_data
= test_data
;
1581 spin_unlock_bh(&drbg
->drbg_lock
);
1584 /***************************************************************
1585 * Kernel crypto API cipher invocations requested by DRBG
1586 ***************************************************************/
1588 #if defined(CONFIG_CRYPTO_DRBG_HASH) || defined(CONFIG_CRYPTO_DRBG_HMAC)
1590 struct shash_desc shash
;
1594 static int drbg_init_hash_kernel(struct drbg_state
*drbg
)
1596 struct sdesc
*sdesc
;
1597 struct crypto_shash
*tfm
;
1599 tfm
= crypto_alloc_shash(drbg
->core
->backend_cra_name
, 0, 0);
1601 pr_info("DRBG: could not allocate digest TFM handle\n");
1602 return PTR_ERR(tfm
);
1604 BUG_ON(drbg_blocklen(drbg
) != crypto_shash_digestsize(tfm
));
1605 sdesc
= kzalloc(sizeof(struct shash_desc
) + crypto_shash_descsize(tfm
),
1608 crypto_free_shash(tfm
);
1612 sdesc
->shash
.tfm
= tfm
;
1613 sdesc
->shash
.flags
= 0;
1614 drbg
->priv_data
= sdesc
;
1618 static int drbg_fini_hash_kernel(struct drbg_state
*drbg
)
1620 struct sdesc
*sdesc
= (struct sdesc
*)drbg
->priv_data
;
1622 crypto_free_shash(sdesc
->shash
.tfm
);
1625 drbg
->priv_data
= NULL
;
1629 static int drbg_kcapi_hash(struct drbg_state
*drbg
, const unsigned char *key
,
1630 unsigned char *outval
, const struct list_head
*in
)
1632 struct sdesc
*sdesc
= (struct sdesc
*)drbg
->priv_data
;
1633 struct drbg_string
*input
= NULL
;
1636 crypto_shash_setkey(sdesc
->shash
.tfm
, key
, drbg_statelen(drbg
));
1637 crypto_shash_init(&sdesc
->shash
);
1638 list_for_each_entry(input
, in
, list
)
1639 crypto_shash_update(&sdesc
->shash
, input
->buf
, input
->len
);
1640 return crypto_shash_final(&sdesc
->shash
, outval
);
1642 #endif /* (CONFIG_CRYPTO_DRBG_HASH || CONFIG_CRYPTO_DRBG_HMAC) */
1644 #ifdef CONFIG_CRYPTO_DRBG_CTR
1645 static int drbg_init_sym_kernel(struct drbg_state
*drbg
)
1648 struct crypto_blkcipher
*tfm
;
1650 tfm
= crypto_alloc_blkcipher(drbg
->core
->backend_cra_name
, 0, 0);
1652 pr_info("DRBG: could not allocate cipher TFM handle\n");
1653 return PTR_ERR(tfm
);
1655 BUG_ON(drbg_blocklen(drbg
) != crypto_blkcipher_blocksize(tfm
));
1656 drbg
->priv_data
= tfm
;
1660 static int drbg_fini_sym_kernel(struct drbg_state
*drbg
)
1662 struct crypto_blkcipher
*tfm
=
1663 (struct crypto_blkcipher
*)drbg
->priv_data
;
1665 crypto_free_blkcipher(tfm
);
1666 drbg
->priv_data
= NULL
;
1670 static int drbg_kcapi_sym(struct drbg_state
*drbg
, const unsigned char *key
,
1671 unsigned char *outval
, const struct drbg_string
*in
)
1674 struct scatterlist sg_in
, sg_out
;
1675 struct blkcipher_desc desc
;
1676 struct crypto_blkcipher
*tfm
=
1677 (struct crypto_blkcipher
*)drbg
->priv_data
;
1681 crypto_blkcipher_setkey(tfm
, key
, (drbg_keylen(drbg
)));
1682 /* there is only component in *in */
1683 sg_init_one(&sg_in
, in
->buf
, in
->len
);
1684 sg_init_one(&sg_out
, outval
, drbg_blocklen(drbg
));
1685 ret
= crypto_blkcipher_encrypt(&desc
, &sg_out
, &sg_in
, in
->len
);
1689 #endif /* CONFIG_CRYPTO_DRBG_CTR */
1691 /***************************************************************
1692 * Kernel crypto API interface to register DRBG
1693 ***************************************************************/
1696 * Look up the DRBG flags by given kernel crypto API cra_name
1697 * The code uses the drbg_cores definition to do this
1699 * @cra_name kernel crypto API cra_name
1700 * @coreref reference to integer which is filled with the pointer to
1701 * the applicable core
1702 * @pr reference for setting prediction resistance
1706 static inline void drbg_convert_tfm_core(const char *cra_driver_name
,
1707 int *coreref
, bool *pr
)
1714 /* disassemble the names */
1715 if (!memcmp(cra_driver_name
, "drbg_nopr_", 10)) {
1718 } else if (!memcmp(cra_driver_name
, "drbg_pr_", 8)) {
1724 /* remove the first part */
1725 len
= strlen(cra_driver_name
) - start
;
1726 for (i
= 0; ARRAY_SIZE(drbg_cores
) > i
; i
++) {
1727 if (!memcmp(cra_driver_name
+ start
, drbg_cores
[i
].cra_name
,
1735 static int drbg_kcapi_init(struct crypto_tfm
*tfm
)
1737 struct drbg_state
*drbg
= crypto_tfm_ctx(tfm
);
1741 drbg_convert_tfm_core(crypto_tfm_alg_driver_name(tfm
), &coreref
, &pr
);
1743 * when personalization string is needed, the caller must call reset
1744 * and provide the personalization string as seed information
1746 return drbg_instantiate(drbg
, NULL
, coreref
, pr
);
1749 static void drbg_kcapi_cleanup(struct crypto_tfm
*tfm
)
1751 drbg_uninstantiate(crypto_tfm_ctx(tfm
));
1755 * Generate random numbers invoked by the kernel crypto API:
1756 * The API of the kernel crypto API is extended as follows:
1758 * If dlen is larger than zero, rdata is interpreted as the output buffer
1759 * where random data is to be stored.
1761 * If dlen is zero, rdata is interpreted as a pointer to a struct drbg_gen
1762 * which holds the additional information string that is used for the
1763 * DRBG generation process. The output buffer that is to be used to store
1764 * data is also pointed to by struct drbg_gen.
1766 static int drbg_kcapi_random(struct crypto_rng
*tfm
, u8
*rdata
,
1769 struct drbg_state
*drbg
= crypto_rng_ctx(tfm
);
1771 return drbg_generate_long(drbg
, rdata
, dlen
, NULL
);
1773 struct drbg_gen
*data
= (struct drbg_gen
*)rdata
;
1774 struct drbg_string addtl
;
1775 /* catch NULL pointer */
1778 drbg_set_testdata(drbg
, data
->test_data
);
1779 /* linked list variable is now local to allow modification */
1780 drbg_string_fill(&addtl
, data
->addtl
->buf
, data
->addtl
->len
);
1781 return drbg_generate_long(drbg
, data
->outbuf
, data
->outlen
,
1787 * Reset the DRBG invoked by the kernel crypto API
1788 * The reset implies a full re-initialization of the DRBG. Similar to the
1789 * generate function of drbg_kcapi_random, this function extends the
1790 * kernel crypto API interface with struct drbg_gen
1792 static int drbg_kcapi_reset(struct crypto_rng
*tfm
, u8
*seed
, unsigned int slen
)
1794 struct drbg_state
*drbg
= crypto_rng_ctx(tfm
);
1795 struct crypto_tfm
*tfm_base
= crypto_rng_tfm(tfm
);
1797 struct drbg_string seed_string
;
1800 drbg_uninstantiate(drbg
);
1801 drbg_convert_tfm_core(crypto_tfm_alg_driver_name(tfm_base
), &coreref
,
1804 drbg_string_fill(&seed_string
, seed
, slen
);
1805 return drbg_instantiate(drbg
, &seed_string
, coreref
, pr
);
1807 struct drbg_gen
*data
= (struct drbg_gen
*)seed
;
1808 /* allow invocation of API call with NULL, 0 */
1810 return drbg_instantiate(drbg
, NULL
, coreref
, pr
);
1811 drbg_set_testdata(drbg
, data
->test_data
);
1812 /* linked list variable is now local to allow modification */
1813 drbg_string_fill(&seed_string
, data
->addtl
->buf
,
1815 return drbg_instantiate(drbg
, &seed_string
, coreref
, pr
);
1819 /***************************************************************
1820 * Kernel module: code to load the module
1821 ***************************************************************/
1824 * Tests as defined in 11.3.2 in addition to the cipher tests: testing
1825 * of the error handling.
1827 * Note: testing of failing seed source as defined in 11.3.2 is not applicable
1828 * as seed source of get_random_bytes does not fail.
1830 * Note 2: There is no sensible way of testing the reseed counter
1831 * enforcement, so skip it.
1833 static inline int __init
drbg_healthcheck_sanity(void)
1835 #ifdef CONFIG_CRYPTO_FIPS
1837 #define OUTBUFLEN 16
1838 unsigned char buf
[OUTBUFLEN
];
1839 struct drbg_state
*drbg
= NULL
;
1844 struct drbg_string addtl
;
1845 size_t max_addtllen
, max_request_bytes
;
1847 /* only perform test in FIPS mode */
1851 #ifdef CONFIG_CRYPTO_DRBG_CTR
1852 drbg_convert_tfm_core("drbg_nopr_ctr_aes128", &coreref
, &pr
);
1853 #elif defined CONFIG_CRYPTO_DRBG_HASH
1854 drbg_convert_tfm_core("drbg_nopr_sha256", &coreref
, &pr
);
1856 drbg_convert_tfm_core("drbg_nopr_hmac_sha256", &coreref
, &pr
);
1859 drbg
= kzalloc(sizeof(struct drbg_state
), GFP_KERNEL
);
1864 * if the following tests fail, it is likely that there is a buffer
1865 * overflow as buf is much smaller than the requested or provided
1866 * string lengths -- in case the error handling does not succeed
1867 * we may get an OOPS. And we want to get an OOPS as this is a
1871 /* get a valid instance of DRBG for following tests */
1872 ret
= drbg_instantiate(drbg
, NULL
, coreref
, pr
);
1877 max_addtllen
= drbg_max_addtl(drbg
);
1878 max_request_bytes
= drbg_max_request_bytes(drbg
);
1879 drbg_string_fill(&addtl
, buf
, max_addtllen
+ 1);
1880 /* overflow addtllen with additonal info string */
1881 len
= drbg_generate(drbg
, buf
, OUTBUFLEN
, &addtl
);
1883 /* overflow max_bits */
1884 len
= drbg_generate(drbg
, buf
, (max_request_bytes
+ 1), NULL
);
1886 drbg_uninstantiate(drbg
);
1888 /* overflow max addtllen with personalization string */
1889 ret
= drbg_instantiate(drbg
, &addtl
, coreref
, pr
);
1891 /* all tests passed */
1894 pr_devel("DRBG: Sanity tests for failure code paths successfully "
1897 drbg_uninstantiate(drbg
);
1901 #else /* CONFIG_CRYPTO_FIPS */
1903 #endif /* CONFIG_CRYPTO_FIPS */
1906 static struct crypto_alg drbg_algs
[22];
1909 * Fill the array drbg_algs used to register the different DRBGs
1910 * with the kernel crypto API. To fill the array, the information
1911 * from drbg_cores[] is used.
1913 static inline void __init
drbg_fill_array(struct crypto_alg
*alg
,
1914 const struct drbg_core
*core
, int pr
)
1917 static int priority
= 100;
1919 memset(alg
, 0, sizeof(struct crypto_alg
));
1920 memcpy(alg
->cra_name
, "stdrng", 6);
1922 memcpy(alg
->cra_driver_name
, "drbg_pr_", 8);
1925 memcpy(alg
->cra_driver_name
, "drbg_nopr_", 10);
1928 memcpy(alg
->cra_driver_name
+ pos
, core
->cra_name
,
1929 strlen(core
->cra_name
));
1931 alg
->cra_priority
= priority
;
1934 * If FIPS mode enabled, the selected DRBG shall have the
1935 * highest cra_priority over other stdrng instances to ensure
1939 alg
->cra_priority
+= 200;
1941 alg
->cra_flags
= CRYPTO_ALG_TYPE_RNG
;
1942 alg
->cra_ctxsize
= sizeof(struct drbg_state
);
1943 alg
->cra_type
= &crypto_rng_type
;
1944 alg
->cra_module
= THIS_MODULE
;
1945 alg
->cra_init
= drbg_kcapi_init
;
1946 alg
->cra_exit
= drbg_kcapi_cleanup
;
1947 alg
->cra_u
.rng
.rng_make_random
= drbg_kcapi_random
;
1948 alg
->cra_u
.rng
.rng_reset
= drbg_kcapi_reset
;
1949 alg
->cra_u
.rng
.seedsize
= 0;
1952 static int __init
drbg_init(void)
1954 unsigned int i
= 0; /* pointer to drbg_algs */
1955 unsigned int j
= 0; /* pointer to drbg_cores */
1958 ret
= drbg_healthcheck_sanity();
1962 if (ARRAY_SIZE(drbg_cores
) * 2 > ARRAY_SIZE(drbg_algs
)) {
1963 pr_info("DRBG: Cannot register all DRBG types"
1964 "(slots needed: %zu, slots available: %zu)\n",
1965 ARRAY_SIZE(drbg_cores
) * 2, ARRAY_SIZE(drbg_algs
));
1970 * each DRBG definition can be used with PR and without PR, thus
1971 * we instantiate each DRBG in drbg_cores[] twice.
1973 * As the order of placing them into the drbg_algs array matters
1974 * (the later DRBGs receive a higher cra_priority) we register the
1975 * prediction resistance DRBGs first as the should not be too
1978 for (j
= 0; ARRAY_SIZE(drbg_cores
) > j
; j
++, i
++)
1979 drbg_fill_array(&drbg_algs
[i
], &drbg_cores
[j
], 1);
1980 for (j
= 0; ARRAY_SIZE(drbg_cores
) > j
; j
++, i
++)
1981 drbg_fill_array(&drbg_algs
[i
], &drbg_cores
[j
], 0);
1982 return crypto_register_algs(drbg_algs
, (ARRAY_SIZE(drbg_cores
) * 2));
1985 static void __exit
drbg_exit(void)
1987 crypto_unregister_algs(drbg_algs
, (ARRAY_SIZE(drbg_cores
) * 2));
1990 module_init(drbg_init
);
1991 module_exit(drbg_exit
);
1992 #ifndef CRYPTO_DRBG_HASH_STRING
1993 #define CRYPTO_DRBG_HASH_STRING ""
1995 #ifndef CRYPTO_DRBG_HMAC_STRING
1996 #define CRYPTO_DRBG_HMAC_STRING ""
1998 #ifndef CRYPTO_DRBG_CTR_STRING
1999 #define CRYPTO_DRBG_CTR_STRING ""
2001 MODULE_LICENSE("GPL");
2002 MODULE_AUTHOR("Stephan Mueller <smueller@chronox.de>");
2003 MODULE_DESCRIPTION("NIST SP800-90A Deterministic Random Bit Generator (DRBG) "
2004 "using following cores: "
2005 CRYPTO_DRBG_HASH_STRING
2006 CRYPTO_DRBG_HMAC_STRING
2007 CRYPTO_DRBG_CTR_STRING
);