2 * DRBG: Deterministic Random Bits Generator
3 * Based on NIST Recommended DRBG from NIST SP800-90A with the following
5 * * CTR DRBG with DF with AES-128, AES-192, AES-256 cores
6 * * Hash DRBG with DF with SHA-1, SHA-256, SHA-384, SHA-512 cores
7 * * HMAC DRBG with DF with SHA-1, SHA-256, SHA-384, SHA-512 cores
8 * * with and without prediction resistance
10 * Copyright Stephan Mueller <smueller@chronox.de>, 2014
12 * Redistribution and use in source and binary forms, with or without
13 * modification, are permitted provided that the following conditions
15 * 1. Redistributions of source code must retain the above copyright
16 * notice, and the entire permission notice in its entirety,
17 * including the disclaimer of warranties.
18 * 2. Redistributions in binary form must reproduce the above copyright
19 * notice, this list of conditions and the following disclaimer in the
20 * documentation and/or other materials provided with the distribution.
21 * 3. The name of the author may not be used to endorse or promote
22 * products derived from this software without specific prior
25 * ALTERNATIVELY, this product may be distributed under the terms of
26 * the GNU General Public License, in which case the provisions of the GPL are
27 * required INSTEAD OF the above restrictions. (This clause is
28 * necessary due to a potential bad interaction between the GPL and
29 * the restrictions contained in a BSD-style copyright.)
31 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
32 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
33 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, ALL OF
34 * WHICH ARE HEREBY DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE
35 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
36 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
37 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
38 * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
39 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
40 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
41 * USE OF THIS SOFTWARE, EVEN IF NOT ADVISED OF THE POSSIBILITY OF SUCH
46 * The SP 800-90A DRBG allows the user to specify a personalization string
47 * for initialization as well as an additional information string for each
48 * random number request. The following code fragments show how a caller
49 * uses the kernel crypto API to use the full functionality of the DRBG.
51 * Usage without any additional data
52 * ---------------------------------
53 * struct crypto_rng *drng;
57 * drng = crypto_alloc_rng(drng_name, 0, 0);
58 * err = crypto_rng_get_bytes(drng, &data, DATALEN);
59 * crypto_free_rng(drng);
62 * Usage with personalization string during initialization
63 * -------------------------------------------------------
64 * struct crypto_rng *drng;
67 * struct drbg_string pers;
68 * char personalization[11] = "some-string";
70 * drbg_string_fill(&pers, personalization, strlen(personalization));
71 * drng = crypto_alloc_rng(drng_name, 0, 0);
72 * // The reset completely re-initializes the DRBG with the provided
73 * // personalization string
74 * err = crypto_rng_reset(drng, &personalization, strlen(personalization));
75 * err = crypto_rng_get_bytes(drng, &data, DATALEN);
76 * crypto_free_rng(drng);
79 * Usage with additional information string during random number request
80 * ---------------------------------------------------------------------
81 * struct crypto_rng *drng;
84 * char addtl_string[11] = "some-string";
85 * string drbg_string addtl;
87 * drbg_string_fill(&addtl, addtl_string, strlen(addtl_string));
88 * drng = crypto_alloc_rng(drng_name, 0, 0);
89 * // The following call is a wrapper to crypto_rng_get_bytes() and returns
90 * // the same error codes.
91 * err = crypto_drbg_get_bytes_addtl(drng, &data, DATALEN, &addtl);
92 * crypto_free_rng(drng);
95 * Usage with personalization and additional information strings
96 * -------------------------------------------------------------
97 * Just mix both scenarios above.
100 #include <crypto/drbg.h>
101 #include <linux/kernel.h>
103 /***************************************************************
104 * Backend cipher definitions available to DRBG
105 ***************************************************************/
108 * The order of the DRBG definitions here matter: every DRBG is registered
109 * as stdrng. Each DRBG receives an increasing cra_priority values the later
110 * they are defined in this array (see drbg_fill_array).
112 * HMAC DRBGs are favored over Hash DRBGs over CTR DRBGs, and
113 * the SHA256 / AES 256 over other ciphers. Thus, the favored
114 * DRBGs are the latest entries in this array.
116 static const struct drbg_core drbg_cores
[] = {
117 #ifdef CONFIG_CRYPTO_DRBG_CTR
119 .flags
= DRBG_CTR
| DRBG_STRENGTH128
,
120 .statelen
= 32, /* 256 bits as defined in 10.2.1 */
121 .blocklen_bytes
= 16,
122 .cra_name
= "ctr_aes128",
123 .backend_cra_name
= "aes",
125 .flags
= DRBG_CTR
| DRBG_STRENGTH192
,
126 .statelen
= 40, /* 320 bits as defined in 10.2.1 */
127 .blocklen_bytes
= 16,
128 .cra_name
= "ctr_aes192",
129 .backend_cra_name
= "aes",
131 .flags
= DRBG_CTR
| DRBG_STRENGTH256
,
132 .statelen
= 48, /* 384 bits as defined in 10.2.1 */
133 .blocklen_bytes
= 16,
134 .cra_name
= "ctr_aes256",
135 .backend_cra_name
= "aes",
137 #endif /* CONFIG_CRYPTO_DRBG_CTR */
138 #ifdef CONFIG_CRYPTO_DRBG_HASH
140 .flags
= DRBG_HASH
| DRBG_STRENGTH128
,
141 .statelen
= 55, /* 440 bits */
142 .blocklen_bytes
= 20,
144 .backend_cra_name
= "sha1",
146 .flags
= DRBG_HASH
| DRBG_STRENGTH256
,
147 .statelen
= 111, /* 888 bits */
148 .blocklen_bytes
= 48,
149 .cra_name
= "sha384",
150 .backend_cra_name
= "sha384",
152 .flags
= DRBG_HASH
| DRBG_STRENGTH256
,
153 .statelen
= 111, /* 888 bits */
154 .blocklen_bytes
= 64,
155 .cra_name
= "sha512",
156 .backend_cra_name
= "sha512",
158 .flags
= DRBG_HASH
| DRBG_STRENGTH256
,
159 .statelen
= 55, /* 440 bits */
160 .blocklen_bytes
= 32,
161 .cra_name
= "sha256",
162 .backend_cra_name
= "sha256",
164 #endif /* CONFIG_CRYPTO_DRBG_HASH */
165 #ifdef CONFIG_CRYPTO_DRBG_HMAC
167 .flags
= DRBG_HMAC
| DRBG_STRENGTH128
,
168 .statelen
= 20, /* block length of cipher */
169 .blocklen_bytes
= 20,
170 .cra_name
= "hmac_sha1",
171 .backend_cra_name
= "hmac(sha1)",
173 .flags
= DRBG_HMAC
| DRBG_STRENGTH256
,
174 .statelen
= 48, /* block length of cipher */
175 .blocklen_bytes
= 48,
176 .cra_name
= "hmac_sha384",
177 .backend_cra_name
= "hmac(sha384)",
179 .flags
= DRBG_HMAC
| DRBG_STRENGTH256
,
180 .statelen
= 64, /* block length of cipher */
181 .blocklen_bytes
= 64,
182 .cra_name
= "hmac_sha512",
183 .backend_cra_name
= "hmac(sha512)",
185 .flags
= DRBG_HMAC
| DRBG_STRENGTH256
,
186 .statelen
= 32, /* block length of cipher */
187 .blocklen_bytes
= 32,
188 .cra_name
= "hmac_sha256",
189 .backend_cra_name
= "hmac(sha256)",
191 #endif /* CONFIG_CRYPTO_DRBG_HMAC */
194 static int drbg_uninstantiate(struct drbg_state
*drbg
);
196 /******************************************************************
197 * Generic helper functions
198 ******************************************************************/
201 * Return strength of DRBG according to SP800-90A section 8.4
203 * @flags DRBG flags reference
205 * Return: normalized strength in *bytes* value or 32 as default
206 * to counter programming errors
208 static inline unsigned short drbg_sec_strength(drbg_flag_t flags
)
210 switch (flags
& DRBG_STRENGTH_MASK
) {
211 case DRBG_STRENGTH128
:
213 case DRBG_STRENGTH192
:
215 case DRBG_STRENGTH256
:
223 * Convert an integer into a byte representation of this integer.
224 * The byte representation is big-endian
226 * @val value to be converted
227 * @buf buffer holding the converted integer -- caller must ensure that
228 * buffer size is at least 32 bit
230 #if (defined(CONFIG_CRYPTO_DRBG_HASH) || defined(CONFIG_CRYPTO_DRBG_CTR))
231 static inline void drbg_cpu_to_be32(__u32 val
, unsigned char *buf
)
236 struct s
*conversion
= (struct s
*) buf
;
238 conversion
->conv
= cpu_to_be32(val
);
240 #endif /* defined(CONFIG_CRYPTO_DRBG_HASH) || defined(CONFIG_CRYPTO_DRBG_CTR) */
242 /******************************************************************
243 * CTR DRBG callback functions
244 ******************************************************************/
246 #ifdef CONFIG_CRYPTO_DRBG_CTR
247 #define CRYPTO_DRBG_CTR_STRING "CTR "
248 MODULE_ALIAS_CRYPTO("drbg_pr_ctr_aes256");
249 MODULE_ALIAS_CRYPTO("drbg_nopr_ctr_aes256");
250 MODULE_ALIAS_CRYPTO("drbg_pr_ctr_aes192");
251 MODULE_ALIAS_CRYPTO("drbg_nopr_ctr_aes192");
252 MODULE_ALIAS_CRYPTO("drbg_pr_ctr_aes128");
253 MODULE_ALIAS_CRYPTO("drbg_nopr_ctr_aes128");
255 static void drbg_kcapi_symsetkey(struct drbg_state
*drbg
,
256 const unsigned char *key
);
257 static int drbg_kcapi_sym(struct drbg_state
*drbg
, unsigned char *outval
,
258 const struct drbg_string
*in
);
259 static int drbg_init_sym_kernel(struct drbg_state
*drbg
);
260 static int drbg_fini_sym_kernel(struct drbg_state
*drbg
);
261 static int drbg_kcapi_sym_ctr(struct drbg_state
*drbg
,
262 u8
*inbuf
, u32 inbuflen
,
263 u8
*outbuf
, u32 outlen
);
264 #define DRBG_CTR_NULL_LEN 128
265 #define DRBG_OUTSCRATCHLEN DRBG_CTR_NULL_LEN
267 /* BCC function for CTR DRBG as defined in 10.4.3 */
268 static int drbg_ctr_bcc(struct drbg_state
*drbg
,
269 unsigned char *out
, const unsigned char *key
,
270 struct list_head
*in
)
273 struct drbg_string
*curr
= NULL
;
274 struct drbg_string data
;
277 drbg_string_fill(&data
, out
, drbg_blocklen(drbg
));
279 /* 10.4.3 step 2 / 4 */
280 drbg_kcapi_symsetkey(drbg
, key
);
281 list_for_each_entry(curr
, in
, list
) {
282 const unsigned char *pos
= curr
->buf
;
283 size_t len
= curr
->len
;
284 /* 10.4.3 step 4.1 */
286 /* 10.4.3 step 4.2 */
287 if (drbg_blocklen(drbg
) == cnt
) {
289 ret
= drbg_kcapi_sym(drbg
, out
, &data
);
299 /* 10.4.3 step 4.2 for last block */
301 ret
= drbg_kcapi_sym(drbg
, out
, &data
);
307 * scratchpad usage: drbg_ctr_update is interlinked with drbg_ctr_df
308 * (and drbg_ctr_bcc, but this function does not need any temporary buffers),
309 * the scratchpad is used as follows:
312 * start: drbg->scratchpad
313 * length: drbg_statelen(drbg) + drbg_blocklen(drbg)
314 * note: the cipher writing into this variable works
315 * blocklen-wise. Now, when the statelen is not a multiple
316 * of blocklen, the generateion loop below "spills over"
317 * by at most blocklen. Thus, we need to give sufficient
320 * start: drbg->scratchpad +
321 * drbg_statelen(drbg) + drbg_blocklen(drbg)
322 * length: drbg_statelen(drbg)
326 * start: df_data + drbg_statelen(drbg)
327 * length: drbg_blocklen(drbg)
329 * start: pad + drbg_blocklen(drbg)
330 * length: drbg_blocklen(drbg)
332 * start: iv + drbg_blocklen(drbg)
333 * length: drbg_satelen(drbg) + drbg_blocklen(drbg)
334 * note: temp is the buffer that the BCC function operates
335 * on. BCC operates blockwise. drbg_statelen(drbg)
336 * is sufficient when the DRBG state length is a multiple
337 * of the block size. For AES192 (and maybe other ciphers)
338 * this is not correct and the length for temp is
339 * insufficient (yes, that also means for such ciphers,
340 * the final output of all BCC rounds are truncated).
341 * Therefore, add drbg_blocklen(drbg) to cover all
345 /* Derivation Function for CTR DRBG as defined in 10.4.2 */
346 static int drbg_ctr_df(struct drbg_state
*drbg
,
347 unsigned char *df_data
, size_t bytes_to_return
,
348 struct list_head
*seedlist
)
351 unsigned char L_N
[8];
353 struct drbg_string S1
, S2
, S4
, cipherin
;
355 unsigned char *pad
= df_data
+ drbg_statelen(drbg
);
356 unsigned char *iv
= pad
+ drbg_blocklen(drbg
);
357 unsigned char *temp
= iv
+ drbg_blocklen(drbg
);
359 unsigned int templen
= 0;
363 const unsigned char *K
= (unsigned char *)
364 "\x00\x01\x02\x03\x04\x05\x06\x07"
365 "\x08\x09\x0a\x0b\x0c\x0d\x0e\x0f"
366 "\x10\x11\x12\x13\x14\x15\x16\x17"
367 "\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f";
369 size_t generated_len
= 0;
371 struct drbg_string
*seed
= NULL
;
373 memset(pad
, 0, drbg_blocklen(drbg
));
374 memset(iv
, 0, drbg_blocklen(drbg
));
376 /* 10.4.2 step 1 is implicit as we work byte-wise */
379 if ((512/8) < bytes_to_return
)
382 /* 10.4.2 step 2 -- calculate the entire length of all input data */
383 list_for_each_entry(seed
, seedlist
, list
)
384 inputlen
+= seed
->len
;
385 drbg_cpu_to_be32(inputlen
, &L_N
[0]);
388 drbg_cpu_to_be32(bytes_to_return
, &L_N
[4]);
390 /* 10.4.2 step 5: length is L_N, input_string, one byte, padding */
391 padlen
= (inputlen
+ sizeof(L_N
) + 1) % (drbg_blocklen(drbg
));
392 /* wrap the padlen appropriately */
394 padlen
= drbg_blocklen(drbg
) - padlen
;
396 * pad / padlen contains the 0x80 byte and the following zero bytes.
397 * As the calculated padlen value only covers the number of zero
398 * bytes, this value has to be incremented by one for the 0x80 byte.
403 /* 10.4.2 step 4 -- first fill the linked list and then order it */
404 drbg_string_fill(&S1
, iv
, drbg_blocklen(drbg
));
405 list_add_tail(&S1
.list
, &bcc_list
);
406 drbg_string_fill(&S2
, L_N
, sizeof(L_N
));
407 list_add_tail(&S2
.list
, &bcc_list
);
408 list_splice_tail(seedlist
, &bcc_list
);
409 drbg_string_fill(&S4
, pad
, padlen
);
410 list_add_tail(&S4
.list
, &bcc_list
);
413 while (templen
< (drbg_keylen(drbg
) + (drbg_blocklen(drbg
)))) {
415 * 10.4.2 step 9.1 - the padding is implicit as the buffer
416 * holds zeros after allocation -- even the increment of i
417 * is irrelevant as the increment remains within length of i
419 drbg_cpu_to_be32(i
, iv
);
420 /* 10.4.2 step 9.2 -- BCC and concatenation with temp */
421 ret
= drbg_ctr_bcc(drbg
, temp
+ templen
, K
, &bcc_list
);
424 /* 10.4.2 step 9.3 */
426 templen
+= drbg_blocklen(drbg
);
430 X
= temp
+ (drbg_keylen(drbg
));
431 drbg_string_fill(&cipherin
, X
, drbg_blocklen(drbg
));
433 /* 10.4.2 step 12: overwriting of outval is implemented in next step */
436 drbg_kcapi_symsetkey(drbg
, temp
);
437 while (generated_len
< bytes_to_return
) {
440 * 10.4.2 step 13.1: the truncation of the key length is
441 * implicit as the key is only drbg_blocklen in size based on
442 * the implementation of the cipher function callback
444 ret
= drbg_kcapi_sym(drbg
, X
, &cipherin
);
447 blocklen
= (drbg_blocklen(drbg
) <
448 (bytes_to_return
- generated_len
)) ?
449 drbg_blocklen(drbg
) :
450 (bytes_to_return
- generated_len
);
451 /* 10.4.2 step 13.2 and 14 */
452 memcpy(df_data
+ generated_len
, X
, blocklen
);
453 generated_len
+= blocklen
;
459 memset(iv
, 0, drbg_blocklen(drbg
));
460 memset(temp
, 0, drbg_statelen(drbg
) + drbg_blocklen(drbg
));
461 memset(pad
, 0, drbg_blocklen(drbg
));
466 * update function of CTR DRBG as defined in 10.2.1.2
468 * The reseed variable has an enhanced meaning compared to the update
469 * functions of the other DRBGs as follows:
470 * 0 => initial seed from initialization
471 * 1 => reseed via drbg_seed
472 * 2 => first invocation from drbg_ctr_update when addtl is present. In
473 * this case, the df_data scratchpad is not deleted so that it is
474 * available for another calls to prevent calling the DF function
476 * 3 => second invocation from drbg_ctr_update. When the update function
477 * was called with addtl, the df_data memory already contains the
478 * DFed addtl information and we do not need to call DF again.
480 static int drbg_ctr_update(struct drbg_state
*drbg
, struct list_head
*seed
,
484 /* 10.2.1.2 step 1 */
485 unsigned char *temp
= drbg
->scratchpad
;
486 unsigned char *df_data
= drbg
->scratchpad
+ drbg_statelen(drbg
) +
490 memset(df_data
, 0, drbg_statelen(drbg
));
494 * The DRBG uses the CTR mode of the underlying AES cipher. The
495 * CTR mode increments the counter value after the AES operation
496 * but SP800-90A requires that the counter is incremented before
497 * the AES operation. Hence, we increment it at the time we set
500 crypto_inc(drbg
->V
, drbg_blocklen(drbg
));
502 ret
= crypto_skcipher_setkey(drbg
->ctr_handle
, drbg
->C
,
508 /* 10.2.1.3.2 step 2 and 10.2.1.4.2 step 2 */
510 ret
= drbg_ctr_df(drbg
, df_data
, drbg_statelen(drbg
), seed
);
515 ret
= drbg_kcapi_sym_ctr(drbg
, df_data
, drbg_statelen(drbg
),
516 temp
, drbg_statelen(drbg
));
520 /* 10.2.1.2 step 5 */
521 ret
= crypto_skcipher_setkey(drbg
->ctr_handle
, temp
,
525 /* 10.2.1.2 step 6 */
526 memcpy(drbg
->V
, temp
+ drbg_keylen(drbg
), drbg_blocklen(drbg
));
527 /* See above: increment counter by one to compensate timing of CTR op */
528 crypto_inc(drbg
->V
, drbg_blocklen(drbg
));
532 memset(temp
, 0, drbg_statelen(drbg
) + drbg_blocklen(drbg
));
534 memset(df_data
, 0, drbg_statelen(drbg
));
539 * scratchpad use: drbg_ctr_update is called independently from
540 * drbg_ctr_extract_bytes. Therefore, the scratchpad is reused
542 /* Generate function of CTR DRBG as defined in 10.2.1.5.2 */
543 static int drbg_ctr_generate(struct drbg_state
*drbg
,
544 unsigned char *buf
, unsigned int buflen
,
545 struct list_head
*addtl
)
548 int len
= min_t(int, buflen
, INT_MAX
);
550 /* 10.2.1.5.2 step 2 */
551 if (addtl
&& !list_empty(addtl
)) {
552 ret
= drbg_ctr_update(drbg
, addtl
, 2);
557 /* 10.2.1.5.2 step 4.1 */
558 ret
= drbg_kcapi_sym_ctr(drbg
, drbg
->ctr_null_value
, DRBG_CTR_NULL_LEN
,
563 /* 10.2.1.5.2 step 6 */
564 ret
= drbg_ctr_update(drbg
, NULL
, 3);
571 static const struct drbg_state_ops drbg_ctr_ops
= {
572 .update
= drbg_ctr_update
,
573 .generate
= drbg_ctr_generate
,
574 .crypto_init
= drbg_init_sym_kernel
,
575 .crypto_fini
= drbg_fini_sym_kernel
,
577 #endif /* CONFIG_CRYPTO_DRBG_CTR */
579 /******************************************************************
580 * HMAC DRBG callback functions
581 ******************************************************************/
583 #if defined(CONFIG_CRYPTO_DRBG_HASH) || defined(CONFIG_CRYPTO_DRBG_HMAC)
584 static int drbg_kcapi_hash(struct drbg_state
*drbg
, unsigned char *outval
,
585 const struct list_head
*in
);
586 static void drbg_kcapi_hmacsetkey(struct drbg_state
*drbg
,
587 const unsigned char *key
);
588 static int drbg_init_hash_kernel(struct drbg_state
*drbg
);
589 static int drbg_fini_hash_kernel(struct drbg_state
*drbg
);
590 #endif /* (CONFIG_CRYPTO_DRBG_HASH || CONFIG_CRYPTO_DRBG_HMAC) */
592 #ifdef CONFIG_CRYPTO_DRBG_HMAC
593 #define CRYPTO_DRBG_HMAC_STRING "HMAC "
594 MODULE_ALIAS_CRYPTO("drbg_pr_hmac_sha512");
595 MODULE_ALIAS_CRYPTO("drbg_nopr_hmac_sha512");
596 MODULE_ALIAS_CRYPTO("drbg_pr_hmac_sha384");
597 MODULE_ALIAS_CRYPTO("drbg_nopr_hmac_sha384");
598 MODULE_ALIAS_CRYPTO("drbg_pr_hmac_sha256");
599 MODULE_ALIAS_CRYPTO("drbg_nopr_hmac_sha256");
600 MODULE_ALIAS_CRYPTO("drbg_pr_hmac_sha1");
601 MODULE_ALIAS_CRYPTO("drbg_nopr_hmac_sha1");
603 /* update function of HMAC DRBG as defined in 10.1.2.2 */
604 static int drbg_hmac_update(struct drbg_state
*drbg
, struct list_head
*seed
,
609 struct drbg_string seed1
, seed2
, vdata
;
611 LIST_HEAD(vdatalist
);
614 /* 10.1.2.3 step 2 -- memset(0) of C is implicit with kzalloc */
615 memset(drbg
->V
, 1, drbg_statelen(drbg
));
616 drbg_kcapi_hmacsetkey(drbg
, drbg
->C
);
619 drbg_string_fill(&seed1
, drbg
->V
, drbg_statelen(drbg
));
620 list_add_tail(&seed1
.list
, &seedlist
);
621 /* buffer of seed2 will be filled in for loop below with one byte */
622 drbg_string_fill(&seed2
, NULL
, 1);
623 list_add_tail(&seed2
.list
, &seedlist
);
624 /* input data of seed is allowed to be NULL at this point */
626 list_splice_tail(seed
, &seedlist
);
628 drbg_string_fill(&vdata
, drbg
->V
, drbg_statelen(drbg
));
629 list_add_tail(&vdata
.list
, &vdatalist
);
630 for (i
= 2; 0 < i
; i
--) {
631 /* first round uses 0x0, second 0x1 */
632 unsigned char prefix
= DRBG_PREFIX0
;
634 prefix
= DRBG_PREFIX1
;
635 /* 10.1.2.2 step 1 and 4 -- concatenation and HMAC for key */
637 ret
= drbg_kcapi_hash(drbg
, drbg
->C
, &seedlist
);
640 drbg_kcapi_hmacsetkey(drbg
, drbg
->C
);
642 /* 10.1.2.2 step 2 and 5 -- HMAC for V */
643 ret
= drbg_kcapi_hash(drbg
, drbg
->V
, &vdatalist
);
647 /* 10.1.2.2 step 3 */
655 /* generate function of HMAC DRBG as defined in 10.1.2.5 */
656 static int drbg_hmac_generate(struct drbg_state
*drbg
,
659 struct list_head
*addtl
)
663 struct drbg_string data
;
666 /* 10.1.2.5 step 2 */
667 if (addtl
&& !list_empty(addtl
)) {
668 ret
= drbg_hmac_update(drbg
, addtl
, 1);
673 drbg_string_fill(&data
, drbg
->V
, drbg_statelen(drbg
));
674 list_add_tail(&data
.list
, &datalist
);
675 while (len
< buflen
) {
676 unsigned int outlen
= 0;
677 /* 10.1.2.5 step 4.1 */
678 ret
= drbg_kcapi_hash(drbg
, drbg
->V
, &datalist
);
681 outlen
= (drbg_blocklen(drbg
) < (buflen
- len
)) ?
682 drbg_blocklen(drbg
) : (buflen
- len
);
684 /* 10.1.2.5 step 4.2 */
685 memcpy(buf
+ len
, drbg
->V
, outlen
);
689 /* 10.1.2.5 step 6 */
690 if (addtl
&& !list_empty(addtl
))
691 ret
= drbg_hmac_update(drbg
, addtl
, 1);
693 ret
= drbg_hmac_update(drbg
, NULL
, 1);
700 static const struct drbg_state_ops drbg_hmac_ops
= {
701 .update
= drbg_hmac_update
,
702 .generate
= drbg_hmac_generate
,
703 .crypto_init
= drbg_init_hash_kernel
,
704 .crypto_fini
= drbg_fini_hash_kernel
,
706 #endif /* CONFIG_CRYPTO_DRBG_HMAC */
708 /******************************************************************
709 * Hash DRBG callback functions
710 ******************************************************************/
712 #ifdef CONFIG_CRYPTO_DRBG_HASH
713 #define CRYPTO_DRBG_HASH_STRING "HASH "
714 MODULE_ALIAS_CRYPTO("drbg_pr_sha512");
715 MODULE_ALIAS_CRYPTO("drbg_nopr_sha512");
716 MODULE_ALIAS_CRYPTO("drbg_pr_sha384");
717 MODULE_ALIAS_CRYPTO("drbg_nopr_sha384");
718 MODULE_ALIAS_CRYPTO("drbg_pr_sha256");
719 MODULE_ALIAS_CRYPTO("drbg_nopr_sha256");
720 MODULE_ALIAS_CRYPTO("drbg_pr_sha1");
721 MODULE_ALIAS_CRYPTO("drbg_nopr_sha1");
726 * @dst buffer to increment
729 static inline void drbg_add_buf(unsigned char *dst
, size_t dstlen
,
730 const unsigned char *add
, size_t addlen
)
732 /* implied: dstlen > addlen */
733 unsigned char *dstptr
;
734 const unsigned char *addptr
;
735 unsigned int remainder
= 0;
738 dstptr
= dst
+ (dstlen
-1);
739 addptr
= add
+ (addlen
-1);
741 remainder
+= *dstptr
+ *addptr
;
742 *dstptr
= remainder
& 0xff;
744 len
--; dstptr
--; addptr
--;
746 len
= dstlen
- addlen
;
747 while (len
&& remainder
> 0) {
748 remainder
= *dstptr
+ 1;
749 *dstptr
= remainder
& 0xff;
756 * scratchpad usage: as drbg_hash_update and drbg_hash_df are used
757 * interlinked, the scratchpad is used as follows:
759 * start: drbg->scratchpad
760 * length: drbg_statelen(drbg)
762 * start: drbg->scratchpad + drbg_statelen(drbg)
763 * length: drbg_blocklen(drbg)
765 * drbg_hash_process_addtl uses the scratchpad, but fully completes
766 * before either of the functions mentioned before are invoked. Therefore,
767 * drbg_hash_process_addtl does not need to be specifically considered.
770 /* Derivation Function for Hash DRBG as defined in 10.4.1 */
771 static int drbg_hash_df(struct drbg_state
*drbg
,
772 unsigned char *outval
, size_t outlen
,
773 struct list_head
*entropylist
)
777 unsigned char input
[5];
778 unsigned char *tmp
= drbg
->scratchpad
+ drbg_statelen(drbg
);
779 struct drbg_string data
;
783 drbg_cpu_to_be32((outlen
* 8), &input
[1]);
785 /* 10.4.1 step 4.1 -- concatenation of data for input into hash */
786 drbg_string_fill(&data
, input
, 5);
787 list_add(&data
.list
, entropylist
);
790 while (len
< outlen
) {
792 /* 10.4.1 step 4.1 */
793 ret
= drbg_kcapi_hash(drbg
, tmp
, entropylist
);
796 /* 10.4.1 step 4.2 */
798 blocklen
= (drbg_blocklen(drbg
) < (outlen
- len
)) ?
799 drbg_blocklen(drbg
) : (outlen
- len
);
800 memcpy(outval
+ len
, tmp
, blocklen
);
805 memset(tmp
, 0, drbg_blocklen(drbg
));
809 /* update function for Hash DRBG as defined in 10.1.1.2 / 10.1.1.3 */
810 static int drbg_hash_update(struct drbg_state
*drbg
, struct list_head
*seed
,
814 struct drbg_string data1
, data2
;
816 LIST_HEAD(datalist2
);
817 unsigned char *V
= drbg
->scratchpad
;
818 unsigned char prefix
= DRBG_PREFIX1
;
824 /* 10.1.1.3 step 1 */
825 memcpy(V
, drbg
->V
, drbg_statelen(drbg
));
826 drbg_string_fill(&data1
, &prefix
, 1);
827 list_add_tail(&data1
.list
, &datalist
);
828 drbg_string_fill(&data2
, V
, drbg_statelen(drbg
));
829 list_add_tail(&data2
.list
, &datalist
);
831 list_splice_tail(seed
, &datalist
);
833 /* 10.1.1.2 / 10.1.1.3 step 2 and 3 */
834 ret
= drbg_hash_df(drbg
, drbg
->V
, drbg_statelen(drbg
), &datalist
);
838 /* 10.1.1.2 / 10.1.1.3 step 4 */
839 prefix
= DRBG_PREFIX0
;
840 drbg_string_fill(&data1
, &prefix
, 1);
841 list_add_tail(&data1
.list
, &datalist2
);
842 drbg_string_fill(&data2
, drbg
->V
, drbg_statelen(drbg
));
843 list_add_tail(&data2
.list
, &datalist2
);
844 /* 10.1.1.2 / 10.1.1.3 step 4 */
845 ret
= drbg_hash_df(drbg
, drbg
->C
, drbg_statelen(drbg
), &datalist2
);
848 memset(drbg
->scratchpad
, 0, drbg_statelen(drbg
));
852 /* processing of additional information string for Hash DRBG */
853 static int drbg_hash_process_addtl(struct drbg_state
*drbg
,
854 struct list_head
*addtl
)
857 struct drbg_string data1
, data2
;
859 unsigned char prefix
= DRBG_PREFIX2
;
861 /* 10.1.1.4 step 2 */
862 if (!addtl
|| list_empty(addtl
))
865 /* 10.1.1.4 step 2a */
866 drbg_string_fill(&data1
, &prefix
, 1);
867 drbg_string_fill(&data2
, drbg
->V
, drbg_statelen(drbg
));
868 list_add_tail(&data1
.list
, &datalist
);
869 list_add_tail(&data2
.list
, &datalist
);
870 list_splice_tail(addtl
, &datalist
);
871 ret
= drbg_kcapi_hash(drbg
, drbg
->scratchpad
, &datalist
);
875 /* 10.1.1.4 step 2b */
876 drbg_add_buf(drbg
->V
, drbg_statelen(drbg
),
877 drbg
->scratchpad
, drbg_blocklen(drbg
));
880 memset(drbg
->scratchpad
, 0, drbg_blocklen(drbg
));
884 /* Hashgen defined in 10.1.1.4 */
885 static int drbg_hash_hashgen(struct drbg_state
*drbg
,
891 unsigned char *src
= drbg
->scratchpad
;
892 unsigned char *dst
= drbg
->scratchpad
+ drbg_statelen(drbg
);
893 struct drbg_string data
;
896 /* 10.1.1.4 step hashgen 2 */
897 memcpy(src
, drbg
->V
, drbg_statelen(drbg
));
899 drbg_string_fill(&data
, src
, drbg_statelen(drbg
));
900 list_add_tail(&data
.list
, &datalist
);
901 while (len
< buflen
) {
902 unsigned int outlen
= 0;
903 /* 10.1.1.4 step hashgen 4.1 */
904 ret
= drbg_kcapi_hash(drbg
, dst
, &datalist
);
909 outlen
= (drbg_blocklen(drbg
) < (buflen
- len
)) ?
910 drbg_blocklen(drbg
) : (buflen
- len
);
911 /* 10.1.1.4 step hashgen 4.2 */
912 memcpy(buf
+ len
, dst
, outlen
);
914 /* 10.1.1.4 hashgen step 4.3 */
916 crypto_inc(src
, drbg_statelen(drbg
));
920 memset(drbg
->scratchpad
, 0,
921 (drbg_statelen(drbg
) + drbg_blocklen(drbg
)));
925 /* generate function for Hash DRBG as defined in 10.1.1.4 */
926 static int drbg_hash_generate(struct drbg_state
*drbg
,
927 unsigned char *buf
, unsigned int buflen
,
928 struct list_head
*addtl
)
933 unsigned char req
[8];
936 unsigned char prefix
= DRBG_PREFIX3
;
937 struct drbg_string data1
, data2
;
940 /* 10.1.1.4 step 2 */
941 ret
= drbg_hash_process_addtl(drbg
, addtl
);
944 /* 10.1.1.4 step 3 */
945 len
= drbg_hash_hashgen(drbg
, buf
, buflen
);
947 /* this is the value H as documented in 10.1.1.4 */
948 /* 10.1.1.4 step 4 */
949 drbg_string_fill(&data1
, &prefix
, 1);
950 list_add_tail(&data1
.list
, &datalist
);
951 drbg_string_fill(&data2
, drbg
->V
, drbg_statelen(drbg
));
952 list_add_tail(&data2
.list
, &datalist
);
953 ret
= drbg_kcapi_hash(drbg
, drbg
->scratchpad
, &datalist
);
959 /* 10.1.1.4 step 5 */
960 drbg_add_buf(drbg
->V
, drbg_statelen(drbg
),
961 drbg
->scratchpad
, drbg_blocklen(drbg
));
962 drbg_add_buf(drbg
->V
, drbg_statelen(drbg
),
963 drbg
->C
, drbg_statelen(drbg
));
964 u
.req_int
= cpu_to_be64(drbg
->reseed_ctr
);
965 drbg_add_buf(drbg
->V
, drbg_statelen(drbg
), u
.req
, 8);
968 memset(drbg
->scratchpad
, 0, drbg_blocklen(drbg
));
973 * scratchpad usage: as update and generate are used isolated, both
974 * can use the scratchpad
976 static const struct drbg_state_ops drbg_hash_ops
= {
977 .update
= drbg_hash_update
,
978 .generate
= drbg_hash_generate
,
979 .crypto_init
= drbg_init_hash_kernel
,
980 .crypto_fini
= drbg_fini_hash_kernel
,
982 #endif /* CONFIG_CRYPTO_DRBG_HASH */
984 /******************************************************************
985 * Functions common for DRBG implementations
986 ******************************************************************/
988 static inline int __drbg_seed(struct drbg_state
*drbg
, struct list_head
*seed
,
991 int ret
= drbg
->d_ops
->update(drbg
, seed
, reseed
);
997 /* 10.1.1.2 / 10.1.1.3 step 5 */
998 drbg
->reseed_ctr
= 1;
1003 static void drbg_async_seed(struct work_struct
*work
)
1005 struct drbg_string data
;
1006 LIST_HEAD(seedlist
);
1007 struct drbg_state
*drbg
= container_of(work
, struct drbg_state
,
1009 unsigned int entropylen
= drbg_sec_strength(drbg
->core
->flags
);
1010 unsigned char entropy
[32];
1012 BUG_ON(!entropylen
);
1013 BUG_ON(entropylen
> sizeof(entropy
));
1014 get_random_bytes(entropy
, entropylen
);
1016 drbg_string_fill(&data
, entropy
, entropylen
);
1017 list_add_tail(&data
.list
, &seedlist
);
1019 mutex_lock(&drbg
->drbg_mutex
);
1021 /* If nonblocking pool is initialized, deactivate Jitter RNG */
1022 crypto_free_rng(drbg
->jent
);
1025 /* Set seeded to false so that if __drbg_seed fails the
1026 * next generate call will trigger a reseed.
1028 drbg
->seeded
= false;
1030 __drbg_seed(drbg
, &seedlist
, true);
1033 drbg
->reseed_threshold
= drbg_max_requests(drbg
);
1035 mutex_unlock(&drbg
->drbg_mutex
);
1037 memzero_explicit(entropy
, entropylen
);
1041 * Seeding or reseeding of the DRBG
1043 * @drbg: DRBG state struct
1044 * @pers: personalization / additional information buffer
1045 * @reseed: 0 for initial seed process, 1 for reseeding
1049 * error value otherwise
1051 static int drbg_seed(struct drbg_state
*drbg
, struct drbg_string
*pers
,
1055 unsigned char entropy
[((32 + 16) * 2)];
1056 unsigned int entropylen
= drbg_sec_strength(drbg
->core
->flags
);
1057 struct drbg_string data1
;
1058 LIST_HEAD(seedlist
);
1060 /* 9.1 / 9.2 / 9.3.1 step 3 */
1061 if (pers
&& pers
->len
> (drbg_max_addtl(drbg
))) {
1062 pr_devel("DRBG: personalization string too long %zu\n",
1067 if (list_empty(&drbg
->test_data
.list
)) {
1068 drbg_string_fill(&data1
, drbg
->test_data
.buf
,
1069 drbg
->test_data
.len
);
1070 pr_devel("DRBG: using test entropy\n");
1073 * Gather entropy equal to the security strength of the DRBG.
1074 * With a derivation function, a nonce is required in addition
1075 * to the entropy. A nonce must be at least 1/2 of the security
1076 * strength of the DRBG in size. Thus, entropy + nonce is 3/2
1077 * of the strength. The consideration of a nonce is only
1078 * applicable during initial seeding.
1080 BUG_ON(!entropylen
);
1082 entropylen
= ((entropylen
+ 1) / 2) * 3;
1083 BUG_ON((entropylen
* 2) > sizeof(entropy
));
1085 /* Get seed from in-kernel /dev/urandom */
1086 get_random_bytes(entropy
, entropylen
);
1089 drbg_string_fill(&data1
, entropy
, entropylen
);
1090 pr_devel("DRBG: (re)seeding with %u bytes of entropy\n",
1093 /* Get seed from Jitter RNG */
1094 ret
= crypto_rng_get_bytes(drbg
->jent
,
1095 entropy
+ entropylen
,
1098 pr_devel("DRBG: jent failed with %d\n", ret
);
1102 drbg_string_fill(&data1
, entropy
, entropylen
* 2);
1103 pr_devel("DRBG: (re)seeding with %u bytes of entropy\n",
1107 list_add_tail(&data1
.list
, &seedlist
);
1110 * concatenation of entropy with personalization str / addtl input)
1111 * the variable pers is directly handed in by the caller, so check its
1112 * contents whether it is appropriate
1114 if (pers
&& pers
->buf
&& 0 < pers
->len
) {
1115 list_add_tail(&pers
->list
, &seedlist
);
1116 pr_devel("DRBG: using personalization string\n");
1120 memset(drbg
->V
, 0, drbg_statelen(drbg
));
1121 memset(drbg
->C
, 0, drbg_statelen(drbg
));
1124 ret
= __drbg_seed(drbg
, &seedlist
, reseed
);
1126 memzero_explicit(entropy
, entropylen
* 2);
1131 /* Free all substructures in a DRBG state without the DRBG state structure */
1132 static inline void drbg_dealloc_state(struct drbg_state
*drbg
)
1140 kzfree(drbg
->scratchpadbuf
);
1141 drbg
->scratchpadbuf
= NULL
;
1142 drbg
->reseed_ctr
= 0;
1148 * Allocate all sub-structures for a DRBG state.
1149 * The DRBG state structure must already be allocated.
1151 static inline int drbg_alloc_state(struct drbg_state
*drbg
)
1154 unsigned int sb_size
= 0;
1156 switch (drbg
->core
->flags
& DRBG_TYPE_MASK
) {
1157 #ifdef CONFIG_CRYPTO_DRBG_HMAC
1159 drbg
->d_ops
= &drbg_hmac_ops
;
1161 #endif /* CONFIG_CRYPTO_DRBG_HMAC */
1162 #ifdef CONFIG_CRYPTO_DRBG_HASH
1164 drbg
->d_ops
= &drbg_hash_ops
;
1166 #endif /* CONFIG_CRYPTO_DRBG_HASH */
1167 #ifdef CONFIG_CRYPTO_DRBG_CTR
1169 drbg
->d_ops
= &drbg_ctr_ops
;
1171 #endif /* CONFIG_CRYPTO_DRBG_CTR */
1177 ret
= drbg
->d_ops
->crypto_init(drbg
);
1181 drbg
->Vbuf
= kmalloc(drbg_statelen(drbg
) + ret
, GFP_KERNEL
);
1186 drbg
->V
= PTR_ALIGN(drbg
->Vbuf
, ret
+ 1);
1187 drbg
->Cbuf
= kmalloc(drbg_statelen(drbg
) + ret
, GFP_KERNEL
);
1192 drbg
->C
= PTR_ALIGN(drbg
->Cbuf
, ret
+ 1);
1193 /* scratchpad is only generated for CTR and Hash */
1194 if (drbg
->core
->flags
& DRBG_HMAC
)
1196 else if (drbg
->core
->flags
& DRBG_CTR
)
1197 sb_size
= drbg_statelen(drbg
) + drbg_blocklen(drbg
) + /* temp */
1198 drbg_statelen(drbg
) + /* df_data */
1199 drbg_blocklen(drbg
) + /* pad */
1200 drbg_blocklen(drbg
) + /* iv */
1201 drbg_statelen(drbg
) + drbg_blocklen(drbg
); /* temp */
1203 sb_size
= drbg_statelen(drbg
) + drbg_blocklen(drbg
);
1206 drbg
->scratchpadbuf
= kzalloc(sb_size
+ ret
, GFP_KERNEL
);
1207 if (!drbg
->scratchpadbuf
) {
1211 drbg
->scratchpad
= PTR_ALIGN(drbg
->scratchpadbuf
, ret
+ 1);
1217 drbg
->d_ops
->crypto_fini(drbg
);
1219 drbg_dealloc_state(drbg
);
1223 /*************************************************************************
1224 * DRBG interface functions
1225 *************************************************************************/
1228 * DRBG generate function as required by SP800-90A - this function
1229 * generates random numbers
1231 * @drbg DRBG state handle
1232 * @buf Buffer where to store the random numbers -- the buffer must already
1233 * be pre-allocated by caller
1234 * @buflen Length of output buffer - this value defines the number of random
1235 * bytes pulled from DRBG
1236 * @addtl Additional input that is mixed into state, may be NULL -- note
1237 * the entropy is pulled by the DRBG internally unconditionally
1238 * as defined in SP800-90A. The additional input is mixed into
1239 * the state in addition to the pulled entropy.
1241 * return: 0 when all bytes are generated; < 0 in case of an error
1243 static int drbg_generate(struct drbg_state
*drbg
,
1244 unsigned char *buf
, unsigned int buflen
,
1245 struct drbg_string
*addtl
)
1248 LIST_HEAD(addtllist
);
1251 pr_devel("DRBG: not yet seeded\n");
1254 if (0 == buflen
|| !buf
) {
1255 pr_devel("DRBG: no output buffer provided\n");
1258 if (addtl
&& NULL
== addtl
->buf
&& 0 < addtl
->len
) {
1259 pr_devel("DRBG: wrong format of additional information\n");
1265 if (buflen
> (drbg_max_request_bytes(drbg
))) {
1266 pr_devel("DRBG: requested random numbers too large %u\n",
1271 /* 9.3.1 step 3 is implicit with the chosen DRBG */
1274 if (addtl
&& addtl
->len
> (drbg_max_addtl(drbg
))) {
1275 pr_devel("DRBG: additional information string too long %zu\n",
1279 /* 9.3.1 step 5 is implicit with the chosen DRBG */
1282 * 9.3.1 step 6 and 9 supplemented by 9.3.2 step c is implemented
1283 * here. The spec is a bit convoluted here, we make it simpler.
1285 if (drbg
->reseed_threshold
< drbg
->reseed_ctr
)
1286 drbg
->seeded
= false;
1288 if (drbg
->pr
|| !drbg
->seeded
) {
1289 pr_devel("DRBG: reseeding before generation (prediction "
1290 "resistance: %s, state %s)\n",
1291 drbg
->pr
? "true" : "false",
1292 drbg
->seeded
? "seeded" : "unseeded");
1293 /* 9.3.1 steps 7.1 through 7.3 */
1294 len
= drbg_seed(drbg
, addtl
, true);
1297 /* 9.3.1 step 7.4 */
1301 if (addtl
&& 0 < addtl
->len
)
1302 list_add_tail(&addtl
->list
, &addtllist
);
1303 /* 9.3.1 step 8 and 10 */
1304 len
= drbg
->d_ops
->generate(drbg
, buf
, buflen
, &addtllist
);
1306 /* 10.1.1.4 step 6, 10.1.2.5 step 7, 10.2.1.5.2 step 7 */
1312 * Section 11.3.3 requires to re-perform self tests after some
1313 * generated random numbers. The chosen value after which self
1314 * test is performed is arbitrary, but it should be reasonable.
1315 * However, we do not perform the self tests because of the following
1316 * reasons: it is mathematically impossible that the initial self tests
1317 * were successfully and the following are not. If the initial would
1318 * pass and the following would not, the kernel integrity is violated.
1319 * In this case, the entire kernel operation is questionable and it
1320 * is unlikely that the integrity violation only affects the
1321 * correct operation of the DRBG.
1323 * Albeit the following code is commented out, it is provided in
1324 * case somebody has a need to implement the test of 11.3.3.
1327 if (drbg
->reseed_ctr
&& !(drbg
->reseed_ctr
% 4096)) {
1329 pr_devel("DRBG: start to perform self test\n");
1330 if (drbg
->core
->flags
& DRBG_HMAC
)
1331 err
= alg_test("drbg_pr_hmac_sha256",
1332 "drbg_pr_hmac_sha256", 0, 0);
1333 else if (drbg
->core
->flags
& DRBG_CTR
)
1334 err
= alg_test("drbg_pr_ctr_aes128",
1335 "drbg_pr_ctr_aes128", 0, 0);
1337 err
= alg_test("drbg_pr_sha256",
1338 "drbg_pr_sha256", 0, 0);
1340 pr_err("DRBG: periodical self test failed\n");
1342 * uninstantiate implies that from now on, only errors
1343 * are returned when reusing this DRBG cipher handle
1345 drbg_uninstantiate(drbg
);
1348 pr_devel("DRBG: self test successful\n");
1354 * All operations were successful, return 0 as mandated by
1355 * the kernel crypto API interface.
1363 * Wrapper around drbg_generate which can pull arbitrary long strings
1364 * from the DRBG without hitting the maximum request limitation.
1366 * Parameters: see drbg_generate
1367 * Return codes: see drbg_generate -- if one drbg_generate request fails,
1368 * the entire drbg_generate_long request fails
1370 static int drbg_generate_long(struct drbg_state
*drbg
,
1371 unsigned char *buf
, unsigned int buflen
,
1372 struct drbg_string
*addtl
)
1374 unsigned int len
= 0;
1375 unsigned int slice
= 0;
1378 unsigned int chunk
= 0;
1379 slice
= ((buflen
- len
) / drbg_max_request_bytes(drbg
));
1380 chunk
= slice
? drbg_max_request_bytes(drbg
) : (buflen
- len
);
1381 mutex_lock(&drbg
->drbg_mutex
);
1382 err
= drbg_generate(drbg
, buf
+ len
, chunk
, addtl
);
1383 mutex_unlock(&drbg
->drbg_mutex
);
1387 } while (slice
> 0 && (len
< buflen
));
1391 static void drbg_schedule_async_seed(struct random_ready_callback
*rdy
)
1393 struct drbg_state
*drbg
= container_of(rdy
, struct drbg_state
,
1396 schedule_work(&drbg
->seed_work
);
1399 static int drbg_prepare_hrng(struct drbg_state
*drbg
)
1403 /* We do not need an HRNG in test mode. */
1404 if (list_empty(&drbg
->test_data
.list
))
1407 INIT_WORK(&drbg
->seed_work
, drbg_async_seed
);
1409 drbg
->random_ready
.owner
= THIS_MODULE
;
1410 drbg
->random_ready
.func
= drbg_schedule_async_seed
;
1412 err
= add_random_ready_callback(&drbg
->random_ready
);
1423 drbg
->random_ready
.func
= NULL
;
1427 drbg
->jent
= crypto_alloc_rng("jitterentropy_rng", 0, 0);
1430 * Require frequent reseeds until the seed source is fully
1433 drbg
->reseed_threshold
= 50;
1439 * DRBG instantiation function as required by SP800-90A - this function
1440 * sets up the DRBG handle, performs the initial seeding and all sanity
1441 * checks required by SP800-90A
1443 * @drbg memory of state -- if NULL, new memory is allocated
1444 * @pers Personalization string that is mixed into state, may be NULL -- note
1445 * the entropy is pulled by the DRBG internally unconditionally
1446 * as defined in SP800-90A. The additional input is mixed into
1447 * the state in addition to the pulled entropy.
1448 * @coreref reference to core
1449 * @pr prediction resistance enabled
1453 * error value otherwise
1455 static int drbg_instantiate(struct drbg_state
*drbg
, struct drbg_string
*pers
,
1456 int coreref
, bool pr
)
1461 pr_devel("DRBG: Initializing DRBG core %d with prediction resistance "
1462 "%s\n", coreref
, pr
? "enabled" : "disabled");
1463 mutex_lock(&drbg
->drbg_mutex
);
1465 /* 9.1 step 1 is implicit with the selected DRBG type */
1468 * 9.1 step 2 is implicit as caller can select prediction resistance
1469 * and the flag is copied into drbg->flags --
1470 * all DRBG types support prediction resistance
1473 /* 9.1 step 4 is implicit in drbg_sec_strength */
1476 drbg
->core
= &drbg_cores
[coreref
];
1478 drbg
->seeded
= false;
1479 drbg
->reseed_threshold
= drbg_max_requests(drbg
);
1481 ret
= drbg_alloc_state(drbg
);
1485 ret
= drbg_prepare_hrng(drbg
);
1487 goto free_everything
;
1489 if (IS_ERR(drbg
->jent
)) {
1490 ret
= PTR_ERR(drbg
->jent
);
1492 if (fips_enabled
|| ret
!= -ENOENT
)
1493 goto free_everything
;
1494 pr_info("DRBG: Continuing without Jitter RNG\n");
1500 ret
= drbg_seed(drbg
, pers
, reseed
);
1503 goto free_everything
;
1505 mutex_unlock(&drbg
->drbg_mutex
);
1509 mutex_unlock(&drbg
->drbg_mutex
);
1513 mutex_unlock(&drbg
->drbg_mutex
);
1514 drbg_uninstantiate(drbg
);
1519 * DRBG uninstantiate function as required by SP800-90A - this function
1520 * frees all buffers and the DRBG handle
1522 * @drbg DRBG state handle
1527 static int drbg_uninstantiate(struct drbg_state
*drbg
)
1529 if (drbg
->random_ready
.func
) {
1530 del_random_ready_callback(&drbg
->random_ready
);
1531 cancel_work_sync(&drbg
->seed_work
);
1532 crypto_free_rng(drbg
->jent
);
1537 drbg
->d_ops
->crypto_fini(drbg
);
1538 drbg_dealloc_state(drbg
);
1539 /* no scrubbing of test_data -- this shall survive an uninstantiate */
1544 * Helper function for setting the test data in the DRBG
1546 * @drbg DRBG state handle
1548 * @len test data length
1550 static void drbg_kcapi_set_entropy(struct crypto_rng
*tfm
,
1551 const u8
*data
, unsigned int len
)
1553 struct drbg_state
*drbg
= crypto_rng_ctx(tfm
);
1555 mutex_lock(&drbg
->drbg_mutex
);
1556 drbg_string_fill(&drbg
->test_data
, data
, len
);
1557 mutex_unlock(&drbg
->drbg_mutex
);
1560 /***************************************************************
1561 * Kernel crypto API cipher invocations requested by DRBG
1562 ***************************************************************/
1564 #if defined(CONFIG_CRYPTO_DRBG_HASH) || defined(CONFIG_CRYPTO_DRBG_HMAC)
1566 struct shash_desc shash
;
1570 static int drbg_init_hash_kernel(struct drbg_state
*drbg
)
1572 struct sdesc
*sdesc
;
1573 struct crypto_shash
*tfm
;
1575 tfm
= crypto_alloc_shash(drbg
->core
->backend_cra_name
, 0, 0);
1577 pr_info("DRBG: could not allocate digest TFM handle: %s\n",
1578 drbg
->core
->backend_cra_name
);
1579 return PTR_ERR(tfm
);
1581 BUG_ON(drbg_blocklen(drbg
) != crypto_shash_digestsize(tfm
));
1582 sdesc
= kzalloc(sizeof(struct shash_desc
) + crypto_shash_descsize(tfm
),
1585 crypto_free_shash(tfm
);
1589 sdesc
->shash
.tfm
= tfm
;
1590 sdesc
->shash
.flags
= 0;
1591 drbg
->priv_data
= sdesc
;
1593 return crypto_shash_alignmask(tfm
);
1596 static int drbg_fini_hash_kernel(struct drbg_state
*drbg
)
1598 struct sdesc
*sdesc
= (struct sdesc
*)drbg
->priv_data
;
1600 crypto_free_shash(sdesc
->shash
.tfm
);
1603 drbg
->priv_data
= NULL
;
1607 static void drbg_kcapi_hmacsetkey(struct drbg_state
*drbg
,
1608 const unsigned char *key
)
1610 struct sdesc
*sdesc
= (struct sdesc
*)drbg
->priv_data
;
1612 crypto_shash_setkey(sdesc
->shash
.tfm
, key
, drbg_statelen(drbg
));
1615 static int drbg_kcapi_hash(struct drbg_state
*drbg
, unsigned char *outval
,
1616 const struct list_head
*in
)
1618 struct sdesc
*sdesc
= (struct sdesc
*)drbg
->priv_data
;
1619 struct drbg_string
*input
= NULL
;
1621 crypto_shash_init(&sdesc
->shash
);
1622 list_for_each_entry(input
, in
, list
)
1623 crypto_shash_update(&sdesc
->shash
, input
->buf
, input
->len
);
1624 return crypto_shash_final(&sdesc
->shash
, outval
);
1626 #endif /* (CONFIG_CRYPTO_DRBG_HASH || CONFIG_CRYPTO_DRBG_HMAC) */
1628 #ifdef CONFIG_CRYPTO_DRBG_CTR
1629 static int drbg_fini_sym_kernel(struct drbg_state
*drbg
)
1631 struct crypto_cipher
*tfm
=
1632 (struct crypto_cipher
*)drbg
->priv_data
;
1634 crypto_free_cipher(tfm
);
1635 drbg
->priv_data
= NULL
;
1637 if (drbg
->ctr_handle
)
1638 crypto_free_skcipher(drbg
->ctr_handle
);
1639 drbg
->ctr_handle
= NULL
;
1642 skcipher_request_free(drbg
->ctr_req
);
1643 drbg
->ctr_req
= NULL
;
1645 kfree(drbg
->ctr_null_value_buf
);
1646 drbg
->ctr_null_value
= NULL
;
1648 kfree(drbg
->outscratchpadbuf
);
1649 drbg
->outscratchpadbuf
= NULL
;
1654 static void drbg_skcipher_cb(struct crypto_async_request
*req
, int error
)
1656 struct drbg_state
*drbg
= req
->data
;
1658 if (error
== -EINPROGRESS
)
1660 drbg
->ctr_async_err
= error
;
1661 complete(&drbg
->ctr_completion
);
1664 static int drbg_init_sym_kernel(struct drbg_state
*drbg
)
1666 struct crypto_cipher
*tfm
;
1667 struct crypto_skcipher
*sk_tfm
;
1668 struct skcipher_request
*req
;
1669 unsigned int alignmask
;
1670 char ctr_name
[CRYPTO_MAX_ALG_NAME
];
1672 tfm
= crypto_alloc_cipher(drbg
->core
->backend_cra_name
, 0, 0);
1674 pr_info("DRBG: could not allocate cipher TFM handle: %s\n",
1675 drbg
->core
->backend_cra_name
);
1676 return PTR_ERR(tfm
);
1678 BUG_ON(drbg_blocklen(drbg
) != crypto_cipher_blocksize(tfm
));
1679 drbg
->priv_data
= tfm
;
1681 if (snprintf(ctr_name
, CRYPTO_MAX_ALG_NAME
, "ctr(%s)",
1682 drbg
->core
->backend_cra_name
) >= CRYPTO_MAX_ALG_NAME
) {
1683 drbg_fini_sym_kernel(drbg
);
1686 sk_tfm
= crypto_alloc_skcipher(ctr_name
, 0, 0);
1687 if (IS_ERR(sk_tfm
)) {
1688 pr_info("DRBG: could not allocate CTR cipher TFM handle: %s\n",
1690 drbg_fini_sym_kernel(drbg
);
1691 return PTR_ERR(sk_tfm
);
1693 drbg
->ctr_handle
= sk_tfm
;
1695 req
= skcipher_request_alloc(sk_tfm
, GFP_KERNEL
);
1697 pr_info("DRBG: could not allocate request queue\n");
1698 drbg_fini_sym_kernel(drbg
);
1701 drbg
->ctr_req
= req
;
1702 skcipher_request_set_callback(req
, CRYPTO_TFM_REQ_MAY_BACKLOG
,
1703 drbg_skcipher_cb
, drbg
);
1705 alignmask
= crypto_skcipher_alignmask(sk_tfm
);
1706 drbg
->ctr_null_value_buf
= kzalloc(DRBG_CTR_NULL_LEN
+ alignmask
,
1708 if (!drbg
->ctr_null_value_buf
) {
1709 drbg_fini_sym_kernel(drbg
);
1712 drbg
->ctr_null_value
= (u8
*)PTR_ALIGN(drbg
->ctr_null_value_buf
,
1715 drbg
->outscratchpadbuf
= kmalloc(DRBG_OUTSCRATCHLEN
+ alignmask
,
1717 if (!drbg
->outscratchpadbuf
) {
1718 drbg_fini_sym_kernel(drbg
);
1721 drbg
->outscratchpad
= (u8
*)PTR_ALIGN(drbg
->outscratchpadbuf
,
1727 static void drbg_kcapi_symsetkey(struct drbg_state
*drbg
,
1728 const unsigned char *key
)
1730 struct crypto_cipher
*tfm
=
1731 (struct crypto_cipher
*)drbg
->priv_data
;
1733 crypto_cipher_setkey(tfm
, key
, (drbg_keylen(drbg
)));
1736 static int drbg_kcapi_sym(struct drbg_state
*drbg
, unsigned char *outval
,
1737 const struct drbg_string
*in
)
1739 struct crypto_cipher
*tfm
=
1740 (struct crypto_cipher
*)drbg
->priv_data
;
1742 /* there is only component in *in */
1743 BUG_ON(in
->len
< drbg_blocklen(drbg
));
1744 crypto_cipher_encrypt_one(tfm
, outval
, in
->buf
);
1748 static int drbg_kcapi_sym_ctr(struct drbg_state
*drbg
,
1749 u8
*inbuf
, u32 inlen
,
1750 u8
*outbuf
, u32 outlen
)
1752 struct scatterlist sg_in
;
1755 sg_init_one(&sg_in
, inbuf
, inlen
);
1758 u32 cryptlen
= min3(inlen
, outlen
, (u32
)DRBG_OUTSCRATCHLEN
);
1759 struct scatterlist sg_out
;
1761 /* Output buffer may not be valid for SGL, use scratchpad */
1762 sg_init_one(&sg_out
, drbg
->outscratchpad
, cryptlen
);
1763 skcipher_request_set_crypt(drbg
->ctr_req
, &sg_in
, &sg_out
,
1765 ret
= crypto_skcipher_encrypt(drbg
->ctr_req
);
1771 ret
= wait_for_completion_interruptible(
1772 &drbg
->ctr_completion
);
1773 if (!ret
&& !drbg
->ctr_async_err
) {
1774 reinit_completion(&drbg
->ctr_completion
);
1780 init_completion(&drbg
->ctr_completion
);
1782 memcpy(outbuf
, drbg
->outscratchpad
, cryptlen
);
1790 memzero_explicit(drbg
->outscratchpad
, DRBG_OUTSCRATCHLEN
);
1793 #endif /* CONFIG_CRYPTO_DRBG_CTR */
1795 /***************************************************************
1796 * Kernel crypto API interface to register DRBG
1797 ***************************************************************/
1800 * Look up the DRBG flags by given kernel crypto API cra_name
1801 * The code uses the drbg_cores definition to do this
1803 * @cra_name kernel crypto API cra_name
1804 * @coreref reference to integer which is filled with the pointer to
1805 * the applicable core
1806 * @pr reference for setting prediction resistance
1810 static inline void drbg_convert_tfm_core(const char *cra_driver_name
,
1811 int *coreref
, bool *pr
)
1818 /* disassemble the names */
1819 if (!memcmp(cra_driver_name
, "drbg_nopr_", 10)) {
1822 } else if (!memcmp(cra_driver_name
, "drbg_pr_", 8)) {
1828 /* remove the first part */
1829 len
= strlen(cra_driver_name
) - start
;
1830 for (i
= 0; ARRAY_SIZE(drbg_cores
) > i
; i
++) {
1831 if (!memcmp(cra_driver_name
+ start
, drbg_cores
[i
].cra_name
,
1839 static int drbg_kcapi_init(struct crypto_tfm
*tfm
)
1841 struct drbg_state
*drbg
= crypto_tfm_ctx(tfm
);
1843 mutex_init(&drbg
->drbg_mutex
);
1848 static void drbg_kcapi_cleanup(struct crypto_tfm
*tfm
)
1850 drbg_uninstantiate(crypto_tfm_ctx(tfm
));
1854 * Generate random numbers invoked by the kernel crypto API:
1855 * The API of the kernel crypto API is extended as follows:
1857 * src is additional input supplied to the RNG.
1858 * slen is the length of src.
1859 * dst is the output buffer where random data is to be stored.
1860 * dlen is the length of dst.
1862 static int drbg_kcapi_random(struct crypto_rng
*tfm
,
1863 const u8
*src
, unsigned int slen
,
1864 u8
*dst
, unsigned int dlen
)
1866 struct drbg_state
*drbg
= crypto_rng_ctx(tfm
);
1867 struct drbg_string
*addtl
= NULL
;
1868 struct drbg_string string
;
1871 /* linked list variable is now local to allow modification */
1872 drbg_string_fill(&string
, src
, slen
);
1876 return drbg_generate_long(drbg
, dst
, dlen
, addtl
);
1880 * Seed the DRBG invoked by the kernel crypto API
1882 static int drbg_kcapi_seed(struct crypto_rng
*tfm
,
1883 const u8
*seed
, unsigned int slen
)
1885 struct drbg_state
*drbg
= crypto_rng_ctx(tfm
);
1886 struct crypto_tfm
*tfm_base
= crypto_rng_tfm(tfm
);
1888 struct drbg_string string
;
1889 struct drbg_string
*seed_string
= NULL
;
1892 drbg_convert_tfm_core(crypto_tfm_alg_driver_name(tfm_base
), &coreref
,
1895 drbg_string_fill(&string
, seed
, slen
);
1896 seed_string
= &string
;
1899 return drbg_instantiate(drbg
, seed_string
, coreref
, pr
);
1902 /***************************************************************
1903 * Kernel module: code to load the module
1904 ***************************************************************/
1907 * Tests as defined in 11.3.2 in addition to the cipher tests: testing
1908 * of the error handling.
1910 * Note: testing of failing seed source as defined in 11.3.2 is not applicable
1911 * as seed source of get_random_bytes does not fail.
1913 * Note 2: There is no sensible way of testing the reseed counter
1914 * enforcement, so skip it.
1916 static inline int __init
drbg_healthcheck_sanity(void)
1919 #define OUTBUFLEN 16
1920 unsigned char buf
[OUTBUFLEN
];
1921 struct drbg_state
*drbg
= NULL
;
1926 struct drbg_string addtl
;
1927 size_t max_addtllen
, max_request_bytes
;
1929 /* only perform test in FIPS mode */
1933 #ifdef CONFIG_CRYPTO_DRBG_CTR
1934 drbg_convert_tfm_core("drbg_nopr_ctr_aes128", &coreref
, &pr
);
1935 #elif defined CONFIG_CRYPTO_DRBG_HASH
1936 drbg_convert_tfm_core("drbg_nopr_sha256", &coreref
, &pr
);
1938 drbg_convert_tfm_core("drbg_nopr_hmac_sha256", &coreref
, &pr
);
1941 drbg
= kzalloc(sizeof(struct drbg_state
), GFP_KERNEL
);
1945 mutex_init(&drbg
->drbg_mutex
);
1946 drbg
->core
= &drbg_cores
[coreref
];
1947 drbg
->reseed_threshold
= drbg_max_requests(drbg
);
1950 * if the following tests fail, it is likely that there is a buffer
1951 * overflow as buf is much smaller than the requested or provided
1952 * string lengths -- in case the error handling does not succeed
1953 * we may get an OOPS. And we want to get an OOPS as this is a
1957 max_addtllen
= drbg_max_addtl(drbg
);
1958 max_request_bytes
= drbg_max_request_bytes(drbg
);
1959 drbg_string_fill(&addtl
, buf
, max_addtllen
+ 1);
1960 /* overflow addtllen with additonal info string */
1961 len
= drbg_generate(drbg
, buf
, OUTBUFLEN
, &addtl
);
1963 /* overflow max_bits */
1964 len
= drbg_generate(drbg
, buf
, (max_request_bytes
+ 1), NULL
);
1967 /* overflow max addtllen with personalization string */
1968 ret
= drbg_seed(drbg
, &addtl
, false);
1970 /* all tests passed */
1973 pr_devel("DRBG: Sanity tests for failure code paths successfully "
1980 static struct rng_alg drbg_algs
[22];
1983 * Fill the array drbg_algs used to register the different DRBGs
1984 * with the kernel crypto API. To fill the array, the information
1985 * from drbg_cores[] is used.
1987 static inline void __init
drbg_fill_array(struct rng_alg
*alg
,
1988 const struct drbg_core
*core
, int pr
)
1991 static int priority
= 200;
1993 memcpy(alg
->base
.cra_name
, "stdrng", 6);
1995 memcpy(alg
->base
.cra_driver_name
, "drbg_pr_", 8);
1998 memcpy(alg
->base
.cra_driver_name
, "drbg_nopr_", 10);
2001 memcpy(alg
->base
.cra_driver_name
+ pos
, core
->cra_name
,
2002 strlen(core
->cra_name
));
2004 alg
->base
.cra_priority
= priority
;
2007 * If FIPS mode enabled, the selected DRBG shall have the
2008 * highest cra_priority over other stdrng instances to ensure
2012 alg
->base
.cra_priority
+= 200;
2014 alg
->base
.cra_ctxsize
= sizeof(struct drbg_state
);
2015 alg
->base
.cra_module
= THIS_MODULE
;
2016 alg
->base
.cra_init
= drbg_kcapi_init
;
2017 alg
->base
.cra_exit
= drbg_kcapi_cleanup
;
2018 alg
->generate
= drbg_kcapi_random
;
2019 alg
->seed
= drbg_kcapi_seed
;
2020 alg
->set_ent
= drbg_kcapi_set_entropy
;
2024 static int __init
drbg_init(void)
2026 unsigned int i
= 0; /* pointer to drbg_algs */
2027 unsigned int j
= 0; /* pointer to drbg_cores */
2030 ret
= drbg_healthcheck_sanity();
2034 if (ARRAY_SIZE(drbg_cores
) * 2 > ARRAY_SIZE(drbg_algs
)) {
2035 pr_info("DRBG: Cannot register all DRBG types"
2036 "(slots needed: %zu, slots available: %zu)\n",
2037 ARRAY_SIZE(drbg_cores
) * 2, ARRAY_SIZE(drbg_algs
));
2042 * each DRBG definition can be used with PR and without PR, thus
2043 * we instantiate each DRBG in drbg_cores[] twice.
2045 * As the order of placing them into the drbg_algs array matters
2046 * (the later DRBGs receive a higher cra_priority) we register the
2047 * prediction resistance DRBGs first as the should not be too
2050 for (j
= 0; ARRAY_SIZE(drbg_cores
) > j
; j
++, i
++)
2051 drbg_fill_array(&drbg_algs
[i
], &drbg_cores
[j
], 1);
2052 for (j
= 0; ARRAY_SIZE(drbg_cores
) > j
; j
++, i
++)
2053 drbg_fill_array(&drbg_algs
[i
], &drbg_cores
[j
], 0);
2054 return crypto_register_rngs(drbg_algs
, (ARRAY_SIZE(drbg_cores
) * 2));
2057 static void __exit
drbg_exit(void)
2059 crypto_unregister_rngs(drbg_algs
, (ARRAY_SIZE(drbg_cores
) * 2));
2062 module_init(drbg_init
);
2063 module_exit(drbg_exit
);
2064 #ifndef CRYPTO_DRBG_HASH_STRING
2065 #define CRYPTO_DRBG_HASH_STRING ""
2067 #ifndef CRYPTO_DRBG_HMAC_STRING
2068 #define CRYPTO_DRBG_HMAC_STRING ""
2070 #ifndef CRYPTO_DRBG_CTR_STRING
2071 #define CRYPTO_DRBG_CTR_STRING ""
2073 MODULE_LICENSE("GPL");
2074 MODULE_AUTHOR("Stephan Mueller <smueller@chronox.de>");
2075 MODULE_DESCRIPTION("NIST SP800-90A Deterministic Random Bit Generator (DRBG) "
2076 "using following cores: "
2077 CRYPTO_DRBG_HASH_STRING
2078 CRYPTO_DRBG_HMAC_STRING
2079 CRYPTO_DRBG_CTR_STRING
);
2080 MODULE_ALIAS_CRYPTO("stdrng");