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 <crypto/internal/cipher.h>
102 #include <linux/kernel.h>
104 /***************************************************************
105 * Backend cipher definitions available to DRBG
106 ***************************************************************/
109 * The order of the DRBG definitions here matter: every DRBG is registered
110 * as stdrng. Each DRBG receives an increasing cra_priority values the later
111 * they are defined in this array (see drbg_fill_array).
113 * HMAC DRBGs are favored over Hash DRBGs over CTR DRBGs, and
114 * the SHA256 / AES 256 over other ciphers. Thus, the favored
115 * DRBGs are the latest entries in this array.
117 static const struct drbg_core drbg_cores
[] = {
118 #ifdef CONFIG_CRYPTO_DRBG_CTR
120 .flags
= DRBG_CTR
| DRBG_STRENGTH128
,
121 .statelen
= 32, /* 256 bits as defined in 10.2.1 */
122 .blocklen_bytes
= 16,
123 .cra_name
= "ctr_aes128",
124 .backend_cra_name
= "aes",
126 .flags
= DRBG_CTR
| DRBG_STRENGTH192
,
127 .statelen
= 40, /* 320 bits as defined in 10.2.1 */
128 .blocklen_bytes
= 16,
129 .cra_name
= "ctr_aes192",
130 .backend_cra_name
= "aes",
132 .flags
= DRBG_CTR
| DRBG_STRENGTH256
,
133 .statelen
= 48, /* 384 bits as defined in 10.2.1 */
134 .blocklen_bytes
= 16,
135 .cra_name
= "ctr_aes256",
136 .backend_cra_name
= "aes",
138 #endif /* CONFIG_CRYPTO_DRBG_CTR */
139 #ifdef CONFIG_CRYPTO_DRBG_HASH
141 .flags
= DRBG_HASH
| DRBG_STRENGTH128
,
142 .statelen
= 55, /* 440 bits */
143 .blocklen_bytes
= 20,
145 .backend_cra_name
= "sha1",
147 .flags
= DRBG_HASH
| DRBG_STRENGTH256
,
148 .statelen
= 111, /* 888 bits */
149 .blocklen_bytes
= 48,
150 .cra_name
= "sha384",
151 .backend_cra_name
= "sha384",
153 .flags
= DRBG_HASH
| DRBG_STRENGTH256
,
154 .statelen
= 111, /* 888 bits */
155 .blocklen_bytes
= 64,
156 .cra_name
= "sha512",
157 .backend_cra_name
= "sha512",
159 .flags
= DRBG_HASH
| DRBG_STRENGTH256
,
160 .statelen
= 55, /* 440 bits */
161 .blocklen_bytes
= 32,
162 .cra_name
= "sha256",
163 .backend_cra_name
= "sha256",
165 #endif /* CONFIG_CRYPTO_DRBG_HASH */
166 #ifdef CONFIG_CRYPTO_DRBG_HMAC
168 .flags
= DRBG_HMAC
| DRBG_STRENGTH128
,
169 .statelen
= 20, /* block length of cipher */
170 .blocklen_bytes
= 20,
171 .cra_name
= "hmac_sha1",
172 .backend_cra_name
= "hmac(sha1)",
174 .flags
= DRBG_HMAC
| DRBG_STRENGTH256
,
175 .statelen
= 48, /* block length of cipher */
176 .blocklen_bytes
= 48,
177 .cra_name
= "hmac_sha384",
178 .backend_cra_name
= "hmac(sha384)",
180 .flags
= DRBG_HMAC
| DRBG_STRENGTH256
,
181 .statelen
= 32, /* block length of cipher */
182 .blocklen_bytes
= 32,
183 .cra_name
= "hmac_sha256",
184 .backend_cra_name
= "hmac(sha256)",
186 .flags
= DRBG_HMAC
| DRBG_STRENGTH256
,
187 .statelen
= 64, /* block length of cipher */
188 .blocklen_bytes
= 64,
189 .cra_name
= "hmac_sha512",
190 .backend_cra_name
= "hmac(sha512)",
192 #endif /* CONFIG_CRYPTO_DRBG_HMAC */
195 static int drbg_uninstantiate(struct drbg_state
*drbg
);
197 /******************************************************************
198 * Generic helper functions
199 ******************************************************************/
202 * Return strength of DRBG according to SP800-90A section 8.4
204 * @flags DRBG flags reference
206 * Return: normalized strength in *bytes* value or 32 as default
207 * to counter programming errors
209 static inline unsigned short drbg_sec_strength(drbg_flag_t flags
)
211 switch (flags
& DRBG_STRENGTH_MASK
) {
212 case DRBG_STRENGTH128
:
214 case DRBG_STRENGTH192
:
216 case DRBG_STRENGTH256
:
224 * FIPS 140-2 continuous self test for the noise source
225 * The test is performed on the noise source input data. Thus, the function
226 * implicitly knows the size of the buffer to be equal to the security
229 * Note, this function disregards the nonce trailing the entropy data during
232 * drbg->drbg_mutex must have been taken.
235 * @entropy buffer of seed data to be checked
239 * -EAGAIN on when the CTRNG is not yet primed
242 static int drbg_fips_continuous_test(struct drbg_state
*drbg
,
243 const unsigned char *entropy
)
245 unsigned short entropylen
= drbg_sec_strength(drbg
->core
->flags
);
248 if (!IS_ENABLED(CONFIG_CRYPTO_FIPS
))
251 /* skip test if we test the overall system */
252 if (list_empty(&drbg
->test_data
.list
))
254 /* only perform test in FIPS mode */
258 if (!drbg
->fips_primed
) {
259 /* Priming of FIPS test */
260 memcpy(drbg
->prev
, entropy
, entropylen
);
261 drbg
->fips_primed
= true;
262 /* priming: another round is needed */
265 ret
= memcmp(drbg
->prev
, entropy
, entropylen
);
267 panic("DRBG continuous self test failed\n");
268 memcpy(drbg
->prev
, entropy
, entropylen
);
270 /* the test shall pass when the two values are not equal */
275 * Convert an integer into a byte representation of this integer.
276 * The byte representation is big-endian
278 * @val value to be converted
279 * @buf buffer holding the converted integer -- caller must ensure that
280 * buffer size is at least 32 bit
282 #if (defined(CONFIG_CRYPTO_DRBG_HASH) || defined(CONFIG_CRYPTO_DRBG_CTR))
283 static inline void drbg_cpu_to_be32(__u32 val
, unsigned char *buf
)
288 struct s
*conversion
= (struct s
*) buf
;
290 conversion
->conv
= cpu_to_be32(val
);
292 #endif /* defined(CONFIG_CRYPTO_DRBG_HASH) || defined(CONFIG_CRYPTO_DRBG_CTR) */
294 /******************************************************************
295 * CTR DRBG callback functions
296 ******************************************************************/
298 #ifdef CONFIG_CRYPTO_DRBG_CTR
299 #define CRYPTO_DRBG_CTR_STRING "CTR "
300 MODULE_ALIAS_CRYPTO("drbg_pr_ctr_aes256");
301 MODULE_ALIAS_CRYPTO("drbg_nopr_ctr_aes256");
302 MODULE_ALIAS_CRYPTO("drbg_pr_ctr_aes192");
303 MODULE_ALIAS_CRYPTO("drbg_nopr_ctr_aes192");
304 MODULE_ALIAS_CRYPTO("drbg_pr_ctr_aes128");
305 MODULE_ALIAS_CRYPTO("drbg_nopr_ctr_aes128");
307 static void drbg_kcapi_symsetkey(struct drbg_state
*drbg
,
308 const unsigned char *key
);
309 static int drbg_kcapi_sym(struct drbg_state
*drbg
, unsigned char *outval
,
310 const struct drbg_string
*in
);
311 static int drbg_init_sym_kernel(struct drbg_state
*drbg
);
312 static int drbg_fini_sym_kernel(struct drbg_state
*drbg
);
313 static int drbg_kcapi_sym_ctr(struct drbg_state
*drbg
,
314 u8
*inbuf
, u32 inbuflen
,
315 u8
*outbuf
, u32 outlen
);
316 #define DRBG_OUTSCRATCHLEN 256
318 /* BCC function for CTR DRBG as defined in 10.4.3 */
319 static int drbg_ctr_bcc(struct drbg_state
*drbg
,
320 unsigned char *out
, const unsigned char *key
,
321 struct list_head
*in
)
324 struct drbg_string
*curr
= NULL
;
325 struct drbg_string data
;
328 drbg_string_fill(&data
, out
, drbg_blocklen(drbg
));
330 /* 10.4.3 step 2 / 4 */
331 drbg_kcapi_symsetkey(drbg
, key
);
332 list_for_each_entry(curr
, in
, list
) {
333 const unsigned char *pos
= curr
->buf
;
334 size_t len
= curr
->len
;
335 /* 10.4.3 step 4.1 */
337 /* 10.4.3 step 4.2 */
338 if (drbg_blocklen(drbg
) == cnt
) {
340 ret
= drbg_kcapi_sym(drbg
, out
, &data
);
350 /* 10.4.3 step 4.2 for last block */
352 ret
= drbg_kcapi_sym(drbg
, out
, &data
);
358 * scratchpad usage: drbg_ctr_update is interlinked with drbg_ctr_df
359 * (and drbg_ctr_bcc, but this function does not need any temporary buffers),
360 * the scratchpad is used as follows:
363 * start: drbg->scratchpad
364 * length: drbg_statelen(drbg) + drbg_blocklen(drbg)
365 * note: the cipher writing into this variable works
366 * blocklen-wise. Now, when the statelen is not a multiple
367 * of blocklen, the generateion loop below "spills over"
368 * by at most blocklen. Thus, we need to give sufficient
371 * start: drbg->scratchpad +
372 * drbg_statelen(drbg) + drbg_blocklen(drbg)
373 * length: drbg_statelen(drbg)
377 * start: df_data + drbg_statelen(drbg)
378 * length: drbg_blocklen(drbg)
380 * start: pad + drbg_blocklen(drbg)
381 * length: drbg_blocklen(drbg)
383 * start: iv + drbg_blocklen(drbg)
384 * length: drbg_satelen(drbg) + drbg_blocklen(drbg)
385 * note: temp is the buffer that the BCC function operates
386 * on. BCC operates blockwise. drbg_statelen(drbg)
387 * is sufficient when the DRBG state length is a multiple
388 * of the block size. For AES192 (and maybe other ciphers)
389 * this is not correct and the length for temp is
390 * insufficient (yes, that also means for such ciphers,
391 * the final output of all BCC rounds are truncated).
392 * Therefore, add drbg_blocklen(drbg) to cover all
396 /* Derivation Function for CTR DRBG as defined in 10.4.2 */
397 static int drbg_ctr_df(struct drbg_state
*drbg
,
398 unsigned char *df_data
, size_t bytes_to_return
,
399 struct list_head
*seedlist
)
402 unsigned char L_N
[8];
404 struct drbg_string S1
, S2
, S4
, cipherin
;
406 unsigned char *pad
= df_data
+ drbg_statelen(drbg
);
407 unsigned char *iv
= pad
+ drbg_blocklen(drbg
);
408 unsigned char *temp
= iv
+ drbg_blocklen(drbg
);
410 unsigned int templen
= 0;
414 const unsigned char *K
= (unsigned char *)
415 "\x00\x01\x02\x03\x04\x05\x06\x07"
416 "\x08\x09\x0a\x0b\x0c\x0d\x0e\x0f"
417 "\x10\x11\x12\x13\x14\x15\x16\x17"
418 "\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f";
420 size_t generated_len
= 0;
422 struct drbg_string
*seed
= NULL
;
424 memset(pad
, 0, drbg_blocklen(drbg
));
425 memset(iv
, 0, drbg_blocklen(drbg
));
427 /* 10.4.2 step 1 is implicit as we work byte-wise */
430 if ((512/8) < bytes_to_return
)
433 /* 10.4.2 step 2 -- calculate the entire length of all input data */
434 list_for_each_entry(seed
, seedlist
, list
)
435 inputlen
+= seed
->len
;
436 drbg_cpu_to_be32(inputlen
, &L_N
[0]);
439 drbg_cpu_to_be32(bytes_to_return
, &L_N
[4]);
441 /* 10.4.2 step 5: length is L_N, input_string, one byte, padding */
442 padlen
= (inputlen
+ sizeof(L_N
) + 1) % (drbg_blocklen(drbg
));
443 /* wrap the padlen appropriately */
445 padlen
= drbg_blocklen(drbg
) - padlen
;
447 * pad / padlen contains the 0x80 byte and the following zero bytes.
448 * As the calculated padlen value only covers the number of zero
449 * bytes, this value has to be incremented by one for the 0x80 byte.
454 /* 10.4.2 step 4 -- first fill the linked list and then order it */
455 drbg_string_fill(&S1
, iv
, drbg_blocklen(drbg
));
456 list_add_tail(&S1
.list
, &bcc_list
);
457 drbg_string_fill(&S2
, L_N
, sizeof(L_N
));
458 list_add_tail(&S2
.list
, &bcc_list
);
459 list_splice_tail(seedlist
, &bcc_list
);
460 drbg_string_fill(&S4
, pad
, padlen
);
461 list_add_tail(&S4
.list
, &bcc_list
);
464 while (templen
< (drbg_keylen(drbg
) + (drbg_blocklen(drbg
)))) {
466 * 10.4.2 step 9.1 - the padding is implicit as the buffer
467 * holds zeros after allocation -- even the increment of i
468 * is irrelevant as the increment remains within length of i
470 drbg_cpu_to_be32(i
, iv
);
471 /* 10.4.2 step 9.2 -- BCC and concatenation with temp */
472 ret
= drbg_ctr_bcc(drbg
, temp
+ templen
, K
, &bcc_list
);
475 /* 10.4.2 step 9.3 */
477 templen
+= drbg_blocklen(drbg
);
481 X
= temp
+ (drbg_keylen(drbg
));
482 drbg_string_fill(&cipherin
, X
, drbg_blocklen(drbg
));
484 /* 10.4.2 step 12: overwriting of outval is implemented in next step */
487 drbg_kcapi_symsetkey(drbg
, temp
);
488 while (generated_len
< bytes_to_return
) {
491 * 10.4.2 step 13.1: the truncation of the key length is
492 * implicit as the key is only drbg_blocklen in size based on
493 * the implementation of the cipher function callback
495 ret
= drbg_kcapi_sym(drbg
, X
, &cipherin
);
498 blocklen
= (drbg_blocklen(drbg
) <
499 (bytes_to_return
- generated_len
)) ?
500 drbg_blocklen(drbg
) :
501 (bytes_to_return
- generated_len
);
502 /* 10.4.2 step 13.2 and 14 */
503 memcpy(df_data
+ generated_len
, X
, blocklen
);
504 generated_len
+= blocklen
;
510 memset(iv
, 0, drbg_blocklen(drbg
));
511 memset(temp
, 0, drbg_statelen(drbg
) + drbg_blocklen(drbg
));
512 memset(pad
, 0, drbg_blocklen(drbg
));
517 * update function of CTR DRBG as defined in 10.2.1.2
519 * The reseed variable has an enhanced meaning compared to the update
520 * functions of the other DRBGs as follows:
521 * 0 => initial seed from initialization
522 * 1 => reseed via drbg_seed
523 * 2 => first invocation from drbg_ctr_update when addtl is present. In
524 * this case, the df_data scratchpad is not deleted so that it is
525 * available for another calls to prevent calling the DF function
527 * 3 => second invocation from drbg_ctr_update. When the update function
528 * was called with addtl, the df_data memory already contains the
529 * DFed addtl information and we do not need to call DF again.
531 static int drbg_ctr_update(struct drbg_state
*drbg
, struct list_head
*seed
,
535 /* 10.2.1.2 step 1 */
536 unsigned char *temp
= drbg
->scratchpad
;
537 unsigned char *df_data
= drbg
->scratchpad
+ drbg_statelen(drbg
) +
541 memset(df_data
, 0, drbg_statelen(drbg
));
545 * The DRBG uses the CTR mode of the underlying AES cipher. The
546 * CTR mode increments the counter value after the AES operation
547 * but SP800-90A requires that the counter is incremented before
548 * the AES operation. Hence, we increment it at the time we set
551 crypto_inc(drbg
->V
, drbg_blocklen(drbg
));
553 ret
= crypto_skcipher_setkey(drbg
->ctr_handle
, drbg
->C
,
559 /* 10.2.1.3.2 step 2 and 10.2.1.4.2 step 2 */
561 ret
= drbg_ctr_df(drbg
, df_data
, drbg_statelen(drbg
), seed
);
566 ret
= drbg_kcapi_sym_ctr(drbg
, df_data
, drbg_statelen(drbg
),
567 temp
, drbg_statelen(drbg
));
571 /* 10.2.1.2 step 5 */
572 ret
= crypto_skcipher_setkey(drbg
->ctr_handle
, temp
,
576 /* 10.2.1.2 step 6 */
577 memcpy(drbg
->V
, temp
+ drbg_keylen(drbg
), drbg_blocklen(drbg
));
578 /* See above: increment counter by one to compensate timing of CTR op */
579 crypto_inc(drbg
->V
, drbg_blocklen(drbg
));
583 memset(temp
, 0, drbg_statelen(drbg
) + drbg_blocklen(drbg
));
585 memset(df_data
, 0, drbg_statelen(drbg
));
590 * scratchpad use: drbg_ctr_update is called independently from
591 * drbg_ctr_extract_bytes. Therefore, the scratchpad is reused
593 /* Generate function of CTR DRBG as defined in 10.2.1.5.2 */
594 static int drbg_ctr_generate(struct drbg_state
*drbg
,
595 unsigned char *buf
, unsigned int buflen
,
596 struct list_head
*addtl
)
599 int len
= min_t(int, buflen
, INT_MAX
);
601 /* 10.2.1.5.2 step 2 */
602 if (addtl
&& !list_empty(addtl
)) {
603 ret
= drbg_ctr_update(drbg
, addtl
, 2);
608 /* 10.2.1.5.2 step 4.1 */
609 ret
= drbg_kcapi_sym_ctr(drbg
, NULL
, 0, buf
, len
);
613 /* 10.2.1.5.2 step 6 */
614 ret
= drbg_ctr_update(drbg
, NULL
, 3);
621 static const struct drbg_state_ops drbg_ctr_ops
= {
622 .update
= drbg_ctr_update
,
623 .generate
= drbg_ctr_generate
,
624 .crypto_init
= drbg_init_sym_kernel
,
625 .crypto_fini
= drbg_fini_sym_kernel
,
627 #endif /* CONFIG_CRYPTO_DRBG_CTR */
629 /******************************************************************
630 * HMAC DRBG callback functions
631 ******************************************************************/
633 #if defined(CONFIG_CRYPTO_DRBG_HASH) || defined(CONFIG_CRYPTO_DRBG_HMAC)
634 static int drbg_kcapi_hash(struct drbg_state
*drbg
, unsigned char *outval
,
635 const struct list_head
*in
);
636 static void drbg_kcapi_hmacsetkey(struct drbg_state
*drbg
,
637 const unsigned char *key
);
638 static int drbg_init_hash_kernel(struct drbg_state
*drbg
);
639 static int drbg_fini_hash_kernel(struct drbg_state
*drbg
);
640 #endif /* (CONFIG_CRYPTO_DRBG_HASH || CONFIG_CRYPTO_DRBG_HMAC) */
642 #ifdef CONFIG_CRYPTO_DRBG_HMAC
643 #define CRYPTO_DRBG_HMAC_STRING "HMAC "
644 MODULE_ALIAS_CRYPTO("drbg_pr_hmac_sha512");
645 MODULE_ALIAS_CRYPTO("drbg_nopr_hmac_sha512");
646 MODULE_ALIAS_CRYPTO("drbg_pr_hmac_sha384");
647 MODULE_ALIAS_CRYPTO("drbg_nopr_hmac_sha384");
648 MODULE_ALIAS_CRYPTO("drbg_pr_hmac_sha256");
649 MODULE_ALIAS_CRYPTO("drbg_nopr_hmac_sha256");
650 MODULE_ALIAS_CRYPTO("drbg_pr_hmac_sha1");
651 MODULE_ALIAS_CRYPTO("drbg_nopr_hmac_sha1");
653 /* update function of HMAC DRBG as defined in 10.1.2.2 */
654 static int drbg_hmac_update(struct drbg_state
*drbg
, struct list_head
*seed
,
659 struct drbg_string seed1
, seed2
, vdata
;
661 LIST_HEAD(vdatalist
);
664 /* 10.1.2.3 step 2 -- memset(0) of C is implicit with kzalloc */
665 memset(drbg
->V
, 1, drbg_statelen(drbg
));
666 drbg_kcapi_hmacsetkey(drbg
, drbg
->C
);
669 drbg_string_fill(&seed1
, drbg
->V
, drbg_statelen(drbg
));
670 list_add_tail(&seed1
.list
, &seedlist
);
671 /* buffer of seed2 will be filled in for loop below with one byte */
672 drbg_string_fill(&seed2
, NULL
, 1);
673 list_add_tail(&seed2
.list
, &seedlist
);
674 /* input data of seed is allowed to be NULL at this point */
676 list_splice_tail(seed
, &seedlist
);
678 drbg_string_fill(&vdata
, drbg
->V
, drbg_statelen(drbg
));
679 list_add_tail(&vdata
.list
, &vdatalist
);
680 for (i
= 2; 0 < i
; i
--) {
681 /* first round uses 0x0, second 0x1 */
682 unsigned char prefix
= DRBG_PREFIX0
;
684 prefix
= DRBG_PREFIX1
;
685 /* 10.1.2.2 step 1 and 4 -- concatenation and HMAC for key */
687 ret
= drbg_kcapi_hash(drbg
, drbg
->C
, &seedlist
);
690 drbg_kcapi_hmacsetkey(drbg
, drbg
->C
);
692 /* 10.1.2.2 step 2 and 5 -- HMAC for V */
693 ret
= drbg_kcapi_hash(drbg
, drbg
->V
, &vdatalist
);
697 /* 10.1.2.2 step 3 */
705 /* generate function of HMAC DRBG as defined in 10.1.2.5 */
706 static int drbg_hmac_generate(struct drbg_state
*drbg
,
709 struct list_head
*addtl
)
713 struct drbg_string data
;
716 /* 10.1.2.5 step 2 */
717 if (addtl
&& !list_empty(addtl
)) {
718 ret
= drbg_hmac_update(drbg
, addtl
, 1);
723 drbg_string_fill(&data
, drbg
->V
, drbg_statelen(drbg
));
724 list_add_tail(&data
.list
, &datalist
);
725 while (len
< buflen
) {
726 unsigned int outlen
= 0;
727 /* 10.1.2.5 step 4.1 */
728 ret
= drbg_kcapi_hash(drbg
, drbg
->V
, &datalist
);
731 outlen
= (drbg_blocklen(drbg
) < (buflen
- len
)) ?
732 drbg_blocklen(drbg
) : (buflen
- len
);
734 /* 10.1.2.5 step 4.2 */
735 memcpy(buf
+ len
, drbg
->V
, outlen
);
739 /* 10.1.2.5 step 6 */
740 if (addtl
&& !list_empty(addtl
))
741 ret
= drbg_hmac_update(drbg
, addtl
, 1);
743 ret
= drbg_hmac_update(drbg
, NULL
, 1);
750 static const struct drbg_state_ops drbg_hmac_ops
= {
751 .update
= drbg_hmac_update
,
752 .generate
= drbg_hmac_generate
,
753 .crypto_init
= drbg_init_hash_kernel
,
754 .crypto_fini
= drbg_fini_hash_kernel
,
756 #endif /* CONFIG_CRYPTO_DRBG_HMAC */
758 /******************************************************************
759 * Hash DRBG callback functions
760 ******************************************************************/
762 #ifdef CONFIG_CRYPTO_DRBG_HASH
763 #define CRYPTO_DRBG_HASH_STRING "HASH "
764 MODULE_ALIAS_CRYPTO("drbg_pr_sha512");
765 MODULE_ALIAS_CRYPTO("drbg_nopr_sha512");
766 MODULE_ALIAS_CRYPTO("drbg_pr_sha384");
767 MODULE_ALIAS_CRYPTO("drbg_nopr_sha384");
768 MODULE_ALIAS_CRYPTO("drbg_pr_sha256");
769 MODULE_ALIAS_CRYPTO("drbg_nopr_sha256");
770 MODULE_ALIAS_CRYPTO("drbg_pr_sha1");
771 MODULE_ALIAS_CRYPTO("drbg_nopr_sha1");
776 * @dst buffer to increment
779 static inline void drbg_add_buf(unsigned char *dst
, size_t dstlen
,
780 const unsigned char *add
, size_t addlen
)
782 /* implied: dstlen > addlen */
783 unsigned char *dstptr
;
784 const unsigned char *addptr
;
785 unsigned int remainder
= 0;
788 dstptr
= dst
+ (dstlen
-1);
789 addptr
= add
+ (addlen
-1);
791 remainder
+= *dstptr
+ *addptr
;
792 *dstptr
= remainder
& 0xff;
794 len
--; dstptr
--; addptr
--;
796 len
= dstlen
- addlen
;
797 while (len
&& remainder
> 0) {
798 remainder
= *dstptr
+ 1;
799 *dstptr
= remainder
& 0xff;
806 * scratchpad usage: as drbg_hash_update and drbg_hash_df are used
807 * interlinked, the scratchpad is used as follows:
809 * start: drbg->scratchpad
810 * length: drbg_statelen(drbg)
812 * start: drbg->scratchpad + drbg_statelen(drbg)
813 * length: drbg_blocklen(drbg)
815 * drbg_hash_process_addtl uses the scratchpad, but fully completes
816 * before either of the functions mentioned before are invoked. Therefore,
817 * drbg_hash_process_addtl does not need to be specifically considered.
820 /* Derivation Function for Hash DRBG as defined in 10.4.1 */
821 static int drbg_hash_df(struct drbg_state
*drbg
,
822 unsigned char *outval
, size_t outlen
,
823 struct list_head
*entropylist
)
827 unsigned char input
[5];
828 unsigned char *tmp
= drbg
->scratchpad
+ drbg_statelen(drbg
);
829 struct drbg_string data
;
833 drbg_cpu_to_be32((outlen
* 8), &input
[1]);
835 /* 10.4.1 step 4.1 -- concatenation of data for input into hash */
836 drbg_string_fill(&data
, input
, 5);
837 list_add(&data
.list
, entropylist
);
840 while (len
< outlen
) {
842 /* 10.4.1 step 4.1 */
843 ret
= drbg_kcapi_hash(drbg
, tmp
, entropylist
);
846 /* 10.4.1 step 4.2 */
848 blocklen
= (drbg_blocklen(drbg
) < (outlen
- len
)) ?
849 drbg_blocklen(drbg
) : (outlen
- len
);
850 memcpy(outval
+ len
, tmp
, blocklen
);
855 memset(tmp
, 0, drbg_blocklen(drbg
));
859 /* update function for Hash DRBG as defined in 10.1.1.2 / 10.1.1.3 */
860 static int drbg_hash_update(struct drbg_state
*drbg
, struct list_head
*seed
,
864 struct drbg_string data1
, data2
;
866 LIST_HEAD(datalist2
);
867 unsigned char *V
= drbg
->scratchpad
;
868 unsigned char prefix
= DRBG_PREFIX1
;
874 /* 10.1.1.3 step 1 */
875 memcpy(V
, drbg
->V
, drbg_statelen(drbg
));
876 drbg_string_fill(&data1
, &prefix
, 1);
877 list_add_tail(&data1
.list
, &datalist
);
878 drbg_string_fill(&data2
, V
, drbg_statelen(drbg
));
879 list_add_tail(&data2
.list
, &datalist
);
881 list_splice_tail(seed
, &datalist
);
883 /* 10.1.1.2 / 10.1.1.3 step 2 and 3 */
884 ret
= drbg_hash_df(drbg
, drbg
->V
, drbg_statelen(drbg
), &datalist
);
888 /* 10.1.1.2 / 10.1.1.3 step 4 */
889 prefix
= DRBG_PREFIX0
;
890 drbg_string_fill(&data1
, &prefix
, 1);
891 list_add_tail(&data1
.list
, &datalist2
);
892 drbg_string_fill(&data2
, drbg
->V
, drbg_statelen(drbg
));
893 list_add_tail(&data2
.list
, &datalist2
);
894 /* 10.1.1.2 / 10.1.1.3 step 4 */
895 ret
= drbg_hash_df(drbg
, drbg
->C
, drbg_statelen(drbg
), &datalist2
);
898 memset(drbg
->scratchpad
, 0, drbg_statelen(drbg
));
902 /* processing of additional information string for Hash DRBG */
903 static int drbg_hash_process_addtl(struct drbg_state
*drbg
,
904 struct list_head
*addtl
)
907 struct drbg_string data1
, data2
;
909 unsigned char prefix
= DRBG_PREFIX2
;
911 /* 10.1.1.4 step 2 */
912 if (!addtl
|| list_empty(addtl
))
915 /* 10.1.1.4 step 2a */
916 drbg_string_fill(&data1
, &prefix
, 1);
917 drbg_string_fill(&data2
, drbg
->V
, drbg_statelen(drbg
));
918 list_add_tail(&data1
.list
, &datalist
);
919 list_add_tail(&data2
.list
, &datalist
);
920 list_splice_tail(addtl
, &datalist
);
921 ret
= drbg_kcapi_hash(drbg
, drbg
->scratchpad
, &datalist
);
925 /* 10.1.1.4 step 2b */
926 drbg_add_buf(drbg
->V
, drbg_statelen(drbg
),
927 drbg
->scratchpad
, drbg_blocklen(drbg
));
930 memset(drbg
->scratchpad
, 0, drbg_blocklen(drbg
));
934 /* Hashgen defined in 10.1.1.4 */
935 static int drbg_hash_hashgen(struct drbg_state
*drbg
,
941 unsigned char *src
= drbg
->scratchpad
;
942 unsigned char *dst
= drbg
->scratchpad
+ drbg_statelen(drbg
);
943 struct drbg_string data
;
946 /* 10.1.1.4 step hashgen 2 */
947 memcpy(src
, drbg
->V
, drbg_statelen(drbg
));
949 drbg_string_fill(&data
, src
, drbg_statelen(drbg
));
950 list_add_tail(&data
.list
, &datalist
);
951 while (len
< buflen
) {
952 unsigned int outlen
= 0;
953 /* 10.1.1.4 step hashgen 4.1 */
954 ret
= drbg_kcapi_hash(drbg
, dst
, &datalist
);
959 outlen
= (drbg_blocklen(drbg
) < (buflen
- len
)) ?
960 drbg_blocklen(drbg
) : (buflen
- len
);
961 /* 10.1.1.4 step hashgen 4.2 */
962 memcpy(buf
+ len
, dst
, outlen
);
964 /* 10.1.1.4 hashgen step 4.3 */
966 crypto_inc(src
, drbg_statelen(drbg
));
970 memset(drbg
->scratchpad
, 0,
971 (drbg_statelen(drbg
) + drbg_blocklen(drbg
)));
975 /* generate function for Hash DRBG as defined in 10.1.1.4 */
976 static int drbg_hash_generate(struct drbg_state
*drbg
,
977 unsigned char *buf
, unsigned int buflen
,
978 struct list_head
*addtl
)
983 unsigned char req
[8];
986 unsigned char prefix
= DRBG_PREFIX3
;
987 struct drbg_string data1
, data2
;
990 /* 10.1.1.4 step 2 */
991 ret
= drbg_hash_process_addtl(drbg
, addtl
);
994 /* 10.1.1.4 step 3 */
995 len
= drbg_hash_hashgen(drbg
, buf
, buflen
);
997 /* this is the value H as documented in 10.1.1.4 */
998 /* 10.1.1.4 step 4 */
999 drbg_string_fill(&data1
, &prefix
, 1);
1000 list_add_tail(&data1
.list
, &datalist
);
1001 drbg_string_fill(&data2
, drbg
->V
, drbg_statelen(drbg
));
1002 list_add_tail(&data2
.list
, &datalist
);
1003 ret
= drbg_kcapi_hash(drbg
, drbg
->scratchpad
, &datalist
);
1009 /* 10.1.1.4 step 5 */
1010 drbg_add_buf(drbg
->V
, drbg_statelen(drbg
),
1011 drbg
->scratchpad
, drbg_blocklen(drbg
));
1012 drbg_add_buf(drbg
->V
, drbg_statelen(drbg
),
1013 drbg
->C
, drbg_statelen(drbg
));
1014 u
.req_int
= cpu_to_be64(drbg
->reseed_ctr
);
1015 drbg_add_buf(drbg
->V
, drbg_statelen(drbg
), u
.req
, 8);
1018 memset(drbg
->scratchpad
, 0, drbg_blocklen(drbg
));
1023 * scratchpad usage: as update and generate are used isolated, both
1024 * can use the scratchpad
1026 static const struct drbg_state_ops drbg_hash_ops
= {
1027 .update
= drbg_hash_update
,
1028 .generate
= drbg_hash_generate
,
1029 .crypto_init
= drbg_init_hash_kernel
,
1030 .crypto_fini
= drbg_fini_hash_kernel
,
1032 #endif /* CONFIG_CRYPTO_DRBG_HASH */
1034 /******************************************************************
1035 * Functions common for DRBG implementations
1036 ******************************************************************/
1038 static inline int __drbg_seed(struct drbg_state
*drbg
, struct list_head
*seed
,
1041 int ret
= drbg
->d_ops
->update(drbg
, seed
, reseed
);
1046 drbg
->seeded
= true;
1047 /* 10.1.1.2 / 10.1.1.3 step 5 */
1048 drbg
->reseed_ctr
= 1;
1053 static inline int drbg_get_random_bytes(struct drbg_state
*drbg
,
1054 unsigned char *entropy
,
1055 unsigned int entropylen
)
1060 get_random_bytes(entropy
, entropylen
);
1061 ret
= drbg_fips_continuous_test(drbg
, entropy
);
1062 if (ret
&& ret
!= -EAGAIN
)
1069 static void drbg_async_seed(struct work_struct
*work
)
1071 struct drbg_string data
;
1072 LIST_HEAD(seedlist
);
1073 struct drbg_state
*drbg
= container_of(work
, struct drbg_state
,
1075 unsigned int entropylen
= drbg_sec_strength(drbg
->core
->flags
);
1076 unsigned char entropy
[32];
1079 BUG_ON(!entropylen
);
1080 BUG_ON(entropylen
> sizeof(entropy
));
1082 drbg_string_fill(&data
, entropy
, entropylen
);
1083 list_add_tail(&data
.list
, &seedlist
);
1085 mutex_lock(&drbg
->drbg_mutex
);
1087 ret
= drbg_get_random_bytes(drbg
, entropy
, entropylen
);
1091 /* Set seeded to false so that if __drbg_seed fails the
1092 * next generate call will trigger a reseed.
1094 drbg
->seeded
= false;
1096 __drbg_seed(drbg
, &seedlist
, true);
1099 drbg
->reseed_threshold
= drbg_max_requests(drbg
);
1102 mutex_unlock(&drbg
->drbg_mutex
);
1104 memzero_explicit(entropy
, entropylen
);
1108 * Seeding or reseeding of the DRBG
1110 * @drbg: DRBG state struct
1111 * @pers: personalization / additional information buffer
1112 * @reseed: 0 for initial seed process, 1 for reseeding
1116 * error value otherwise
1118 static int drbg_seed(struct drbg_state
*drbg
, struct drbg_string
*pers
,
1122 unsigned char entropy
[((32 + 16) * 2)];
1123 unsigned int entropylen
= drbg_sec_strength(drbg
->core
->flags
);
1124 struct drbg_string data1
;
1125 LIST_HEAD(seedlist
);
1127 /* 9.1 / 9.2 / 9.3.1 step 3 */
1128 if (pers
&& pers
->len
> (drbg_max_addtl(drbg
))) {
1129 pr_devel("DRBG: personalization string too long %zu\n",
1134 if (list_empty(&drbg
->test_data
.list
)) {
1135 drbg_string_fill(&data1
, drbg
->test_data
.buf
,
1136 drbg
->test_data
.len
);
1137 pr_devel("DRBG: using test entropy\n");
1140 * Gather entropy equal to the security strength of the DRBG.
1141 * With a derivation function, a nonce is required in addition
1142 * to the entropy. A nonce must be at least 1/2 of the security
1143 * strength of the DRBG in size. Thus, entropy + nonce is 3/2
1144 * of the strength. The consideration of a nonce is only
1145 * applicable during initial seeding.
1147 BUG_ON(!entropylen
);
1149 entropylen
= ((entropylen
+ 1) / 2) * 3;
1150 BUG_ON((entropylen
* 2) > sizeof(entropy
));
1152 /* Get seed from in-kernel /dev/urandom */
1153 ret
= drbg_get_random_bytes(drbg
, entropy
, entropylen
);
1158 drbg_string_fill(&data1
, entropy
, entropylen
);
1159 pr_devel("DRBG: (re)seeding with %u bytes of entropy\n",
1162 /* Get seed from Jitter RNG */
1163 ret
= crypto_rng_get_bytes(drbg
->jent
,
1164 entropy
+ entropylen
,
1167 pr_devel("DRBG: jent failed with %d\n", ret
);
1170 * Do not treat the transient failure of the
1171 * Jitter RNG as an error that needs to be
1172 * reported. The combined number of the
1173 * maximum reseed threshold times the maximum
1174 * number of Jitter RNG transient errors is
1175 * less than the reseed threshold required by
1176 * SP800-90A allowing us to treat the
1177 * transient errors as such.
1179 * However, we mandate that at least the first
1180 * seeding operation must succeed with the
1183 if (!reseed
|| ret
!= -EAGAIN
)
1187 drbg_string_fill(&data1
, entropy
, entropylen
* 2);
1188 pr_devel("DRBG: (re)seeding with %u bytes of entropy\n",
1192 list_add_tail(&data1
.list
, &seedlist
);
1195 * concatenation of entropy with personalization str / addtl input)
1196 * the variable pers is directly handed in by the caller, so check its
1197 * contents whether it is appropriate
1199 if (pers
&& pers
->buf
&& 0 < pers
->len
) {
1200 list_add_tail(&pers
->list
, &seedlist
);
1201 pr_devel("DRBG: using personalization string\n");
1205 memset(drbg
->V
, 0, drbg_statelen(drbg
));
1206 memset(drbg
->C
, 0, drbg_statelen(drbg
));
1209 ret
= __drbg_seed(drbg
, &seedlist
, reseed
);
1212 memzero_explicit(entropy
, entropylen
* 2);
1217 /* Free all substructures in a DRBG state without the DRBG state structure */
1218 static inline void drbg_dealloc_state(struct drbg_state
*drbg
)
1222 kfree_sensitive(drbg
->Vbuf
);
1225 kfree_sensitive(drbg
->Cbuf
);
1228 kfree_sensitive(drbg
->scratchpadbuf
);
1229 drbg
->scratchpadbuf
= NULL
;
1230 drbg
->reseed_ctr
= 0;
1233 if (IS_ENABLED(CONFIG_CRYPTO_FIPS
)) {
1234 kfree_sensitive(drbg
->prev
);
1236 drbg
->fips_primed
= false;
1241 * Allocate all sub-structures for a DRBG state.
1242 * The DRBG state structure must already be allocated.
1244 static inline int drbg_alloc_state(struct drbg_state
*drbg
)
1247 unsigned int sb_size
= 0;
1249 switch (drbg
->core
->flags
& DRBG_TYPE_MASK
) {
1250 #ifdef CONFIG_CRYPTO_DRBG_HMAC
1252 drbg
->d_ops
= &drbg_hmac_ops
;
1254 #endif /* CONFIG_CRYPTO_DRBG_HMAC */
1255 #ifdef CONFIG_CRYPTO_DRBG_HASH
1257 drbg
->d_ops
= &drbg_hash_ops
;
1259 #endif /* CONFIG_CRYPTO_DRBG_HASH */
1260 #ifdef CONFIG_CRYPTO_DRBG_CTR
1262 drbg
->d_ops
= &drbg_ctr_ops
;
1264 #endif /* CONFIG_CRYPTO_DRBG_CTR */
1270 ret
= drbg
->d_ops
->crypto_init(drbg
);
1274 drbg
->Vbuf
= kmalloc(drbg_statelen(drbg
) + ret
, GFP_KERNEL
);
1279 drbg
->V
= PTR_ALIGN(drbg
->Vbuf
, ret
+ 1);
1280 drbg
->Cbuf
= kmalloc(drbg_statelen(drbg
) + ret
, GFP_KERNEL
);
1285 drbg
->C
= PTR_ALIGN(drbg
->Cbuf
, ret
+ 1);
1286 /* scratchpad is only generated for CTR and Hash */
1287 if (drbg
->core
->flags
& DRBG_HMAC
)
1289 else if (drbg
->core
->flags
& DRBG_CTR
)
1290 sb_size
= drbg_statelen(drbg
) + drbg_blocklen(drbg
) + /* temp */
1291 drbg_statelen(drbg
) + /* df_data */
1292 drbg_blocklen(drbg
) + /* pad */
1293 drbg_blocklen(drbg
) + /* iv */
1294 drbg_statelen(drbg
) + drbg_blocklen(drbg
); /* temp */
1296 sb_size
= drbg_statelen(drbg
) + drbg_blocklen(drbg
);
1299 drbg
->scratchpadbuf
= kzalloc(sb_size
+ ret
, GFP_KERNEL
);
1300 if (!drbg
->scratchpadbuf
) {
1304 drbg
->scratchpad
= PTR_ALIGN(drbg
->scratchpadbuf
, ret
+ 1);
1307 if (IS_ENABLED(CONFIG_CRYPTO_FIPS
)) {
1308 drbg
->prev
= kzalloc(drbg_sec_strength(drbg
->core
->flags
),
1314 drbg
->fips_primed
= false;
1320 drbg
->d_ops
->crypto_fini(drbg
);
1322 drbg_dealloc_state(drbg
);
1326 /*************************************************************************
1327 * DRBG interface functions
1328 *************************************************************************/
1331 * DRBG generate function as required by SP800-90A - this function
1332 * generates random numbers
1334 * @drbg DRBG state handle
1335 * @buf Buffer where to store the random numbers -- the buffer must already
1336 * be pre-allocated by caller
1337 * @buflen Length of output buffer - this value defines the number of random
1338 * bytes pulled from DRBG
1339 * @addtl Additional input that is mixed into state, may be NULL -- note
1340 * the entropy is pulled by the DRBG internally unconditionally
1341 * as defined in SP800-90A. The additional input is mixed into
1342 * the state in addition to the pulled entropy.
1344 * return: 0 when all bytes are generated; < 0 in case of an error
1346 static int drbg_generate(struct drbg_state
*drbg
,
1347 unsigned char *buf
, unsigned int buflen
,
1348 struct drbg_string
*addtl
)
1351 LIST_HEAD(addtllist
);
1354 pr_devel("DRBG: not yet seeded\n");
1357 if (0 == buflen
|| !buf
) {
1358 pr_devel("DRBG: no output buffer provided\n");
1361 if (addtl
&& NULL
== addtl
->buf
&& 0 < addtl
->len
) {
1362 pr_devel("DRBG: wrong format of additional information\n");
1368 if (buflen
> (drbg_max_request_bytes(drbg
))) {
1369 pr_devel("DRBG: requested random numbers too large %u\n",
1374 /* 9.3.1 step 3 is implicit with the chosen DRBG */
1377 if (addtl
&& addtl
->len
> (drbg_max_addtl(drbg
))) {
1378 pr_devel("DRBG: additional information string too long %zu\n",
1382 /* 9.3.1 step 5 is implicit with the chosen DRBG */
1385 * 9.3.1 step 6 and 9 supplemented by 9.3.2 step c is implemented
1386 * here. The spec is a bit convoluted here, we make it simpler.
1388 if (drbg
->reseed_threshold
< drbg
->reseed_ctr
)
1389 drbg
->seeded
= false;
1391 if (drbg
->pr
|| !drbg
->seeded
) {
1392 pr_devel("DRBG: reseeding before generation (prediction "
1393 "resistance: %s, state %s)\n",
1394 drbg
->pr
? "true" : "false",
1395 drbg
->seeded
? "seeded" : "unseeded");
1396 /* 9.3.1 steps 7.1 through 7.3 */
1397 len
= drbg_seed(drbg
, addtl
, true);
1400 /* 9.3.1 step 7.4 */
1404 if (addtl
&& 0 < addtl
->len
)
1405 list_add_tail(&addtl
->list
, &addtllist
);
1406 /* 9.3.1 step 8 and 10 */
1407 len
= drbg
->d_ops
->generate(drbg
, buf
, buflen
, &addtllist
);
1409 /* 10.1.1.4 step 6, 10.1.2.5 step 7, 10.2.1.5.2 step 7 */
1415 * Section 11.3.3 requires to re-perform self tests after some
1416 * generated random numbers. The chosen value after which self
1417 * test is performed is arbitrary, but it should be reasonable.
1418 * However, we do not perform the self tests because of the following
1419 * reasons: it is mathematically impossible that the initial self tests
1420 * were successfully and the following are not. If the initial would
1421 * pass and the following would not, the kernel integrity is violated.
1422 * In this case, the entire kernel operation is questionable and it
1423 * is unlikely that the integrity violation only affects the
1424 * correct operation of the DRBG.
1426 * Albeit the following code is commented out, it is provided in
1427 * case somebody has a need to implement the test of 11.3.3.
1430 if (drbg
->reseed_ctr
&& !(drbg
->reseed_ctr
% 4096)) {
1432 pr_devel("DRBG: start to perform self test\n");
1433 if (drbg
->core
->flags
& DRBG_HMAC
)
1434 err
= alg_test("drbg_pr_hmac_sha256",
1435 "drbg_pr_hmac_sha256", 0, 0);
1436 else if (drbg
->core
->flags
& DRBG_CTR
)
1437 err
= alg_test("drbg_pr_ctr_aes128",
1438 "drbg_pr_ctr_aes128", 0, 0);
1440 err
= alg_test("drbg_pr_sha256",
1441 "drbg_pr_sha256", 0, 0);
1443 pr_err("DRBG: periodical self test failed\n");
1445 * uninstantiate implies that from now on, only errors
1446 * are returned when reusing this DRBG cipher handle
1448 drbg_uninstantiate(drbg
);
1451 pr_devel("DRBG: self test successful\n");
1457 * All operations were successful, return 0 as mandated by
1458 * the kernel crypto API interface.
1466 * Wrapper around drbg_generate which can pull arbitrary long strings
1467 * from the DRBG without hitting the maximum request limitation.
1469 * Parameters: see drbg_generate
1470 * Return codes: see drbg_generate -- if one drbg_generate request fails,
1471 * the entire drbg_generate_long request fails
1473 static int drbg_generate_long(struct drbg_state
*drbg
,
1474 unsigned char *buf
, unsigned int buflen
,
1475 struct drbg_string
*addtl
)
1477 unsigned int len
= 0;
1478 unsigned int slice
= 0;
1481 unsigned int chunk
= 0;
1482 slice
= ((buflen
- len
) / drbg_max_request_bytes(drbg
));
1483 chunk
= slice
? drbg_max_request_bytes(drbg
) : (buflen
- len
);
1484 mutex_lock(&drbg
->drbg_mutex
);
1485 err
= drbg_generate(drbg
, buf
+ len
, chunk
, addtl
);
1486 mutex_unlock(&drbg
->drbg_mutex
);
1490 } while (slice
> 0 && (len
< buflen
));
1494 static void drbg_schedule_async_seed(struct random_ready_callback
*rdy
)
1496 struct drbg_state
*drbg
= container_of(rdy
, struct drbg_state
,
1499 schedule_work(&drbg
->seed_work
);
1502 static int drbg_prepare_hrng(struct drbg_state
*drbg
)
1506 /* We do not need an HRNG in test mode. */
1507 if (list_empty(&drbg
->test_data
.list
))
1510 drbg
->jent
= crypto_alloc_rng("jitterentropy_rng", 0, 0);
1512 INIT_WORK(&drbg
->seed_work
, drbg_async_seed
);
1514 drbg
->random_ready
.owner
= THIS_MODULE
;
1515 drbg
->random_ready
.func
= drbg_schedule_async_seed
;
1517 err
= add_random_ready_callback(&drbg
->random_ready
);
1528 drbg
->random_ready
.func
= NULL
;
1533 * Require frequent reseeds until the seed source is fully
1536 drbg
->reseed_threshold
= 50;
1542 * DRBG instantiation function as required by SP800-90A - this function
1543 * sets up the DRBG handle, performs the initial seeding and all sanity
1544 * checks required by SP800-90A
1546 * @drbg memory of state -- if NULL, new memory is allocated
1547 * @pers Personalization string that is mixed into state, may be NULL -- note
1548 * the entropy is pulled by the DRBG internally unconditionally
1549 * as defined in SP800-90A. The additional input is mixed into
1550 * the state in addition to the pulled entropy.
1551 * @coreref reference to core
1552 * @pr prediction resistance enabled
1556 * error value otherwise
1558 static int drbg_instantiate(struct drbg_state
*drbg
, struct drbg_string
*pers
,
1559 int coreref
, bool pr
)
1564 pr_devel("DRBG: Initializing DRBG core %d with prediction resistance "
1565 "%s\n", coreref
, pr
? "enabled" : "disabled");
1566 mutex_lock(&drbg
->drbg_mutex
);
1568 /* 9.1 step 1 is implicit with the selected DRBG type */
1571 * 9.1 step 2 is implicit as caller can select prediction resistance
1572 * and the flag is copied into drbg->flags --
1573 * all DRBG types support prediction resistance
1576 /* 9.1 step 4 is implicit in drbg_sec_strength */
1579 drbg
->core
= &drbg_cores
[coreref
];
1581 drbg
->seeded
= false;
1582 drbg
->reseed_threshold
= drbg_max_requests(drbg
);
1584 ret
= drbg_alloc_state(drbg
);
1588 ret
= drbg_prepare_hrng(drbg
);
1590 goto free_everything
;
1592 if (IS_ERR(drbg
->jent
)) {
1593 ret
= PTR_ERR(drbg
->jent
);
1595 if (fips_enabled
|| ret
!= -ENOENT
)
1596 goto free_everything
;
1597 pr_info("DRBG: Continuing without Jitter RNG\n");
1603 ret
= drbg_seed(drbg
, pers
, reseed
);
1606 goto free_everything
;
1608 mutex_unlock(&drbg
->drbg_mutex
);
1612 mutex_unlock(&drbg
->drbg_mutex
);
1616 mutex_unlock(&drbg
->drbg_mutex
);
1617 drbg_uninstantiate(drbg
);
1622 * DRBG uninstantiate function as required by SP800-90A - this function
1623 * frees all buffers and the DRBG handle
1625 * @drbg DRBG state handle
1630 static int drbg_uninstantiate(struct drbg_state
*drbg
)
1632 if (drbg
->random_ready
.func
) {
1633 del_random_ready_callback(&drbg
->random_ready
);
1634 cancel_work_sync(&drbg
->seed_work
);
1637 if (!IS_ERR_OR_NULL(drbg
->jent
))
1638 crypto_free_rng(drbg
->jent
);
1642 drbg
->d_ops
->crypto_fini(drbg
);
1643 drbg_dealloc_state(drbg
);
1644 /* no scrubbing of test_data -- this shall survive an uninstantiate */
1649 * Helper function for setting the test data in the DRBG
1651 * @drbg DRBG state handle
1653 * @len test data length
1655 static void drbg_kcapi_set_entropy(struct crypto_rng
*tfm
,
1656 const u8
*data
, unsigned int len
)
1658 struct drbg_state
*drbg
= crypto_rng_ctx(tfm
);
1660 mutex_lock(&drbg
->drbg_mutex
);
1661 drbg_string_fill(&drbg
->test_data
, data
, len
);
1662 mutex_unlock(&drbg
->drbg_mutex
);
1665 /***************************************************************
1666 * Kernel crypto API cipher invocations requested by DRBG
1667 ***************************************************************/
1669 #if defined(CONFIG_CRYPTO_DRBG_HASH) || defined(CONFIG_CRYPTO_DRBG_HMAC)
1671 struct shash_desc shash
;
1675 static int drbg_init_hash_kernel(struct drbg_state
*drbg
)
1677 struct sdesc
*sdesc
;
1678 struct crypto_shash
*tfm
;
1680 tfm
= crypto_alloc_shash(drbg
->core
->backend_cra_name
, 0, 0);
1682 pr_info("DRBG: could not allocate digest TFM handle: %s\n",
1683 drbg
->core
->backend_cra_name
);
1684 return PTR_ERR(tfm
);
1686 BUG_ON(drbg_blocklen(drbg
) != crypto_shash_digestsize(tfm
));
1687 sdesc
= kzalloc(sizeof(struct shash_desc
) + crypto_shash_descsize(tfm
),
1690 crypto_free_shash(tfm
);
1694 sdesc
->shash
.tfm
= tfm
;
1695 drbg
->priv_data
= sdesc
;
1697 return crypto_shash_alignmask(tfm
);
1700 static int drbg_fini_hash_kernel(struct drbg_state
*drbg
)
1702 struct sdesc
*sdesc
= (struct sdesc
*)drbg
->priv_data
;
1704 crypto_free_shash(sdesc
->shash
.tfm
);
1705 kfree_sensitive(sdesc
);
1707 drbg
->priv_data
= NULL
;
1711 static void drbg_kcapi_hmacsetkey(struct drbg_state
*drbg
,
1712 const unsigned char *key
)
1714 struct sdesc
*sdesc
= (struct sdesc
*)drbg
->priv_data
;
1716 crypto_shash_setkey(sdesc
->shash
.tfm
, key
, drbg_statelen(drbg
));
1719 static int drbg_kcapi_hash(struct drbg_state
*drbg
, unsigned char *outval
,
1720 const struct list_head
*in
)
1722 struct sdesc
*sdesc
= (struct sdesc
*)drbg
->priv_data
;
1723 struct drbg_string
*input
= NULL
;
1725 crypto_shash_init(&sdesc
->shash
);
1726 list_for_each_entry(input
, in
, list
)
1727 crypto_shash_update(&sdesc
->shash
, input
->buf
, input
->len
);
1728 return crypto_shash_final(&sdesc
->shash
, outval
);
1730 #endif /* (CONFIG_CRYPTO_DRBG_HASH || CONFIG_CRYPTO_DRBG_HMAC) */
1732 #ifdef CONFIG_CRYPTO_DRBG_CTR
1733 static int drbg_fini_sym_kernel(struct drbg_state
*drbg
)
1735 struct crypto_cipher
*tfm
=
1736 (struct crypto_cipher
*)drbg
->priv_data
;
1738 crypto_free_cipher(tfm
);
1739 drbg
->priv_data
= NULL
;
1741 if (drbg
->ctr_handle
)
1742 crypto_free_skcipher(drbg
->ctr_handle
);
1743 drbg
->ctr_handle
= NULL
;
1746 skcipher_request_free(drbg
->ctr_req
);
1747 drbg
->ctr_req
= NULL
;
1749 kfree(drbg
->outscratchpadbuf
);
1750 drbg
->outscratchpadbuf
= NULL
;
1755 static int drbg_init_sym_kernel(struct drbg_state
*drbg
)
1757 struct crypto_cipher
*tfm
;
1758 struct crypto_skcipher
*sk_tfm
;
1759 struct skcipher_request
*req
;
1760 unsigned int alignmask
;
1761 char ctr_name
[CRYPTO_MAX_ALG_NAME
];
1763 tfm
= crypto_alloc_cipher(drbg
->core
->backend_cra_name
, 0, 0);
1765 pr_info("DRBG: could not allocate cipher TFM handle: %s\n",
1766 drbg
->core
->backend_cra_name
);
1767 return PTR_ERR(tfm
);
1769 BUG_ON(drbg_blocklen(drbg
) != crypto_cipher_blocksize(tfm
));
1770 drbg
->priv_data
= tfm
;
1772 if (snprintf(ctr_name
, CRYPTO_MAX_ALG_NAME
, "ctr(%s)",
1773 drbg
->core
->backend_cra_name
) >= CRYPTO_MAX_ALG_NAME
) {
1774 drbg_fini_sym_kernel(drbg
);
1777 sk_tfm
= crypto_alloc_skcipher(ctr_name
, 0, 0);
1778 if (IS_ERR(sk_tfm
)) {
1779 pr_info("DRBG: could not allocate CTR cipher TFM handle: %s\n",
1781 drbg_fini_sym_kernel(drbg
);
1782 return PTR_ERR(sk_tfm
);
1784 drbg
->ctr_handle
= sk_tfm
;
1785 crypto_init_wait(&drbg
->ctr_wait
);
1787 req
= skcipher_request_alloc(sk_tfm
, GFP_KERNEL
);
1789 pr_info("DRBG: could not allocate request queue\n");
1790 drbg_fini_sym_kernel(drbg
);
1793 drbg
->ctr_req
= req
;
1794 skcipher_request_set_callback(req
, CRYPTO_TFM_REQ_MAY_BACKLOG
|
1795 CRYPTO_TFM_REQ_MAY_SLEEP
,
1796 crypto_req_done
, &drbg
->ctr_wait
);
1798 alignmask
= crypto_skcipher_alignmask(sk_tfm
);
1799 drbg
->outscratchpadbuf
= kmalloc(DRBG_OUTSCRATCHLEN
+ alignmask
,
1801 if (!drbg
->outscratchpadbuf
) {
1802 drbg_fini_sym_kernel(drbg
);
1805 drbg
->outscratchpad
= (u8
*)PTR_ALIGN(drbg
->outscratchpadbuf
,
1808 sg_init_table(&drbg
->sg_in
, 1);
1809 sg_init_one(&drbg
->sg_out
, drbg
->outscratchpad
, DRBG_OUTSCRATCHLEN
);
1814 static void drbg_kcapi_symsetkey(struct drbg_state
*drbg
,
1815 const unsigned char *key
)
1817 struct crypto_cipher
*tfm
=
1818 (struct crypto_cipher
*)drbg
->priv_data
;
1820 crypto_cipher_setkey(tfm
, key
, (drbg_keylen(drbg
)));
1823 static int drbg_kcapi_sym(struct drbg_state
*drbg
, unsigned char *outval
,
1824 const struct drbg_string
*in
)
1826 struct crypto_cipher
*tfm
=
1827 (struct crypto_cipher
*)drbg
->priv_data
;
1829 /* there is only component in *in */
1830 BUG_ON(in
->len
< drbg_blocklen(drbg
));
1831 crypto_cipher_encrypt_one(tfm
, outval
, in
->buf
);
1835 static int drbg_kcapi_sym_ctr(struct drbg_state
*drbg
,
1836 u8
*inbuf
, u32 inlen
,
1837 u8
*outbuf
, u32 outlen
)
1839 struct scatterlist
*sg_in
= &drbg
->sg_in
, *sg_out
= &drbg
->sg_out
;
1840 u32 scratchpad_use
= min_t(u32
, outlen
, DRBG_OUTSCRATCHLEN
);
1844 /* Use caller-provided input buffer */
1845 sg_set_buf(sg_in
, inbuf
, inlen
);
1847 /* Use scratchpad for in-place operation */
1848 inlen
= scratchpad_use
;
1849 memset(drbg
->outscratchpad
, 0, scratchpad_use
);
1850 sg_set_buf(sg_in
, drbg
->outscratchpad
, scratchpad_use
);
1854 u32 cryptlen
= min3(inlen
, outlen
, (u32
)DRBG_OUTSCRATCHLEN
);
1856 /* Output buffer may not be valid for SGL, use scratchpad */
1857 skcipher_request_set_crypt(drbg
->ctr_req
, sg_in
, sg_out
,
1859 ret
= crypto_wait_req(crypto_skcipher_encrypt(drbg
->ctr_req
),
1864 crypto_init_wait(&drbg
->ctr_wait
);
1866 memcpy(outbuf
, drbg
->outscratchpad
, cryptlen
);
1867 memzero_explicit(drbg
->outscratchpad
, cryptlen
);
1877 #endif /* CONFIG_CRYPTO_DRBG_CTR */
1879 /***************************************************************
1880 * Kernel crypto API interface to register DRBG
1881 ***************************************************************/
1884 * Look up the DRBG flags by given kernel crypto API cra_name
1885 * The code uses the drbg_cores definition to do this
1887 * @cra_name kernel crypto API cra_name
1888 * @coreref reference to integer which is filled with the pointer to
1889 * the applicable core
1890 * @pr reference for setting prediction resistance
1894 static inline void drbg_convert_tfm_core(const char *cra_driver_name
,
1895 int *coreref
, bool *pr
)
1902 /* disassemble the names */
1903 if (!memcmp(cra_driver_name
, "drbg_nopr_", 10)) {
1906 } else if (!memcmp(cra_driver_name
, "drbg_pr_", 8)) {
1912 /* remove the first part */
1913 len
= strlen(cra_driver_name
) - start
;
1914 for (i
= 0; ARRAY_SIZE(drbg_cores
) > i
; i
++) {
1915 if (!memcmp(cra_driver_name
+ start
, drbg_cores
[i
].cra_name
,
1923 static int drbg_kcapi_init(struct crypto_tfm
*tfm
)
1925 struct drbg_state
*drbg
= crypto_tfm_ctx(tfm
);
1927 mutex_init(&drbg
->drbg_mutex
);
1932 static void drbg_kcapi_cleanup(struct crypto_tfm
*tfm
)
1934 drbg_uninstantiate(crypto_tfm_ctx(tfm
));
1938 * Generate random numbers invoked by the kernel crypto API:
1939 * The API of the kernel crypto API is extended as follows:
1941 * src is additional input supplied to the RNG.
1942 * slen is the length of src.
1943 * dst is the output buffer where random data is to be stored.
1944 * dlen is the length of dst.
1946 static int drbg_kcapi_random(struct crypto_rng
*tfm
,
1947 const u8
*src
, unsigned int slen
,
1948 u8
*dst
, unsigned int dlen
)
1950 struct drbg_state
*drbg
= crypto_rng_ctx(tfm
);
1951 struct drbg_string
*addtl
= NULL
;
1952 struct drbg_string string
;
1955 /* linked list variable is now local to allow modification */
1956 drbg_string_fill(&string
, src
, slen
);
1960 return drbg_generate_long(drbg
, dst
, dlen
, addtl
);
1964 * Seed the DRBG invoked by the kernel crypto API
1966 static int drbg_kcapi_seed(struct crypto_rng
*tfm
,
1967 const u8
*seed
, unsigned int slen
)
1969 struct drbg_state
*drbg
= crypto_rng_ctx(tfm
);
1970 struct crypto_tfm
*tfm_base
= crypto_rng_tfm(tfm
);
1972 struct drbg_string string
;
1973 struct drbg_string
*seed_string
= NULL
;
1976 drbg_convert_tfm_core(crypto_tfm_alg_driver_name(tfm_base
), &coreref
,
1979 drbg_string_fill(&string
, seed
, slen
);
1980 seed_string
= &string
;
1983 return drbg_instantiate(drbg
, seed_string
, coreref
, pr
);
1986 /***************************************************************
1987 * Kernel module: code to load the module
1988 ***************************************************************/
1991 * Tests as defined in 11.3.2 in addition to the cipher tests: testing
1992 * of the error handling.
1994 * Note: testing of failing seed source as defined in 11.3.2 is not applicable
1995 * as seed source of get_random_bytes does not fail.
1997 * Note 2: There is no sensible way of testing the reseed counter
1998 * enforcement, so skip it.
2000 static inline int __init
drbg_healthcheck_sanity(void)
2003 #define OUTBUFLEN 16
2004 unsigned char buf
[OUTBUFLEN
];
2005 struct drbg_state
*drbg
= NULL
;
2010 struct drbg_string addtl
;
2011 size_t max_addtllen
, max_request_bytes
;
2013 /* only perform test in FIPS mode */
2017 #ifdef CONFIG_CRYPTO_DRBG_CTR
2018 drbg_convert_tfm_core("drbg_nopr_ctr_aes128", &coreref
, &pr
);
2019 #elif defined CONFIG_CRYPTO_DRBG_HASH
2020 drbg_convert_tfm_core("drbg_nopr_sha256", &coreref
, &pr
);
2022 drbg_convert_tfm_core("drbg_nopr_hmac_sha256", &coreref
, &pr
);
2025 drbg
= kzalloc(sizeof(struct drbg_state
), GFP_KERNEL
);
2029 mutex_init(&drbg
->drbg_mutex
);
2030 drbg
->core
= &drbg_cores
[coreref
];
2031 drbg
->reseed_threshold
= drbg_max_requests(drbg
);
2034 * if the following tests fail, it is likely that there is a buffer
2035 * overflow as buf is much smaller than the requested or provided
2036 * string lengths -- in case the error handling does not succeed
2037 * we may get an OOPS. And we want to get an OOPS as this is a
2041 max_addtllen
= drbg_max_addtl(drbg
);
2042 max_request_bytes
= drbg_max_request_bytes(drbg
);
2043 drbg_string_fill(&addtl
, buf
, max_addtllen
+ 1);
2044 /* overflow addtllen with additonal info string */
2045 len
= drbg_generate(drbg
, buf
, OUTBUFLEN
, &addtl
);
2047 /* overflow max_bits */
2048 len
= drbg_generate(drbg
, buf
, (max_request_bytes
+ 1), NULL
);
2051 /* overflow max addtllen with personalization string */
2052 ret
= drbg_seed(drbg
, &addtl
, false);
2054 /* all tests passed */
2057 pr_devel("DRBG: Sanity tests for failure code paths successfully "
2064 static struct rng_alg drbg_algs
[22];
2067 * Fill the array drbg_algs used to register the different DRBGs
2068 * with the kernel crypto API. To fill the array, the information
2069 * from drbg_cores[] is used.
2071 static inline void __init
drbg_fill_array(struct rng_alg
*alg
,
2072 const struct drbg_core
*core
, int pr
)
2075 static int priority
= 200;
2077 memcpy(alg
->base
.cra_name
, "stdrng", 6);
2079 memcpy(alg
->base
.cra_driver_name
, "drbg_pr_", 8);
2082 memcpy(alg
->base
.cra_driver_name
, "drbg_nopr_", 10);
2085 memcpy(alg
->base
.cra_driver_name
+ pos
, core
->cra_name
,
2086 strlen(core
->cra_name
));
2088 alg
->base
.cra_priority
= priority
;
2091 * If FIPS mode enabled, the selected DRBG shall have the
2092 * highest cra_priority over other stdrng instances to ensure
2096 alg
->base
.cra_priority
+= 200;
2098 alg
->base
.cra_ctxsize
= sizeof(struct drbg_state
);
2099 alg
->base
.cra_module
= THIS_MODULE
;
2100 alg
->base
.cra_init
= drbg_kcapi_init
;
2101 alg
->base
.cra_exit
= drbg_kcapi_cleanup
;
2102 alg
->generate
= drbg_kcapi_random
;
2103 alg
->seed
= drbg_kcapi_seed
;
2104 alg
->set_ent
= drbg_kcapi_set_entropy
;
2108 static int __init
drbg_init(void)
2110 unsigned int i
= 0; /* pointer to drbg_algs */
2111 unsigned int j
= 0; /* pointer to drbg_cores */
2114 ret
= drbg_healthcheck_sanity();
2118 if (ARRAY_SIZE(drbg_cores
) * 2 > ARRAY_SIZE(drbg_algs
)) {
2119 pr_info("DRBG: Cannot register all DRBG types"
2120 "(slots needed: %zu, slots available: %zu)\n",
2121 ARRAY_SIZE(drbg_cores
) * 2, ARRAY_SIZE(drbg_algs
));
2126 * each DRBG definition can be used with PR and without PR, thus
2127 * we instantiate each DRBG in drbg_cores[] twice.
2129 * As the order of placing them into the drbg_algs array matters
2130 * (the later DRBGs receive a higher cra_priority) we register the
2131 * prediction resistance DRBGs first as the should not be too
2134 for (j
= 0; ARRAY_SIZE(drbg_cores
) > j
; j
++, i
++)
2135 drbg_fill_array(&drbg_algs
[i
], &drbg_cores
[j
], 1);
2136 for (j
= 0; ARRAY_SIZE(drbg_cores
) > j
; j
++, i
++)
2137 drbg_fill_array(&drbg_algs
[i
], &drbg_cores
[j
], 0);
2138 return crypto_register_rngs(drbg_algs
, (ARRAY_SIZE(drbg_cores
) * 2));
2141 static void __exit
drbg_exit(void)
2143 crypto_unregister_rngs(drbg_algs
, (ARRAY_SIZE(drbg_cores
) * 2));
2146 subsys_initcall(drbg_init
);
2147 module_exit(drbg_exit
);
2148 #ifndef CRYPTO_DRBG_HASH_STRING
2149 #define CRYPTO_DRBG_HASH_STRING ""
2151 #ifndef CRYPTO_DRBG_HMAC_STRING
2152 #define CRYPTO_DRBG_HMAC_STRING ""
2154 #ifndef CRYPTO_DRBG_CTR_STRING
2155 #define CRYPTO_DRBG_CTR_STRING ""
2157 MODULE_LICENSE("GPL");
2158 MODULE_AUTHOR("Stephan Mueller <smueller@chronox.de>");
2159 MODULE_DESCRIPTION("NIST SP800-90A Deterministic Random Bit Generator (DRBG) "
2160 "using following cores: "
2161 CRYPTO_DRBG_HASH_STRING
2162 CRYPTO_DRBG_HMAC_STRING
2163 CRYPTO_DRBG_CTR_STRING
);
2164 MODULE_ALIAS_CRYPTO("stdrng");
2165 MODULE_IMPORT_NS(CRYPTO_INTERNAL
);