blob: 4bb5f93c94cdbc5db48706bab321b2d651f779ed
1 | /* |
2 | * DRBG: Deterministic Random Bits Generator |
3 | * Based on NIST Recommended DRBG from NIST SP800-90A with the following |
4 | * properties: |
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 |
9 | * |
10 | * Copyright Stephan Mueller <smueller@chronox.de>, 2014 |
11 | * |
12 | * Redistribution and use in source and binary forms, with or without |
13 | * modification, are permitted provided that the following conditions |
14 | * are met: |
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 |
23 | * written permission. |
24 | * |
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.) |
30 | * |
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 |
42 | * DAMAGE. |
43 | * |
44 | * DRBG Usage |
45 | * ========== |
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. |
50 | * |
51 | * Usage without any additional data |
52 | * --------------------------------- |
53 | * struct crypto_rng *drng; |
54 | * int err; |
55 | * char data[DATALEN]; |
56 | * |
57 | * drng = crypto_alloc_rng(drng_name, 0, 0); |
58 | * err = crypto_rng_get_bytes(drng, &data, DATALEN); |
59 | * crypto_free_rng(drng); |
60 | * |
61 | * |
62 | * Usage with personalization string during initialization |
63 | * ------------------------------------------------------- |
64 | * struct crypto_rng *drng; |
65 | * int err; |
66 | * char data[DATALEN]; |
67 | * struct drbg_string pers; |
68 | * char personalization[11] = "some-string"; |
69 | * |
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); |
77 | * |
78 | * |
79 | * Usage with additional information string during random number request |
80 | * --------------------------------------------------------------------- |
81 | * struct crypto_rng *drng; |
82 | * int err; |
83 | * char data[DATALEN]; |
84 | * char addtl_string[11] = "some-string"; |
85 | * string drbg_string addtl; |
86 | * |
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); |
93 | * |
94 | * |
95 | * Usage with personalization and additional information strings |
96 | * ------------------------------------------------------------- |
97 | * Just mix both scenarios above. |
98 | */ |
99 | |
100 | #include <crypto/drbg.h> |
101 | #include <linux/kernel.h> |
102 | |
103 | /*************************************************************** |
104 | * Backend cipher definitions available to DRBG |
105 | ***************************************************************/ |
106 | |
107 | /* |
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). |
111 | * |
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. |
115 | */ |
116 | static const struct drbg_core drbg_cores[] = { |
117 | #ifdef CONFIG_CRYPTO_DRBG_CTR |
118 | { |
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", |
124 | }, { |
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", |
130 | }, { |
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", |
136 | }, |
137 | #endif /* CONFIG_CRYPTO_DRBG_CTR */ |
138 | #ifdef CONFIG_CRYPTO_DRBG_HASH |
139 | { |
140 | .flags = DRBG_HASH | DRBG_STRENGTH128, |
141 | .statelen = 55, /* 440 bits */ |
142 | .blocklen_bytes = 20, |
143 | .cra_name = "sha1", |
144 | .backend_cra_name = "sha1", |
145 | }, { |
146 | .flags = DRBG_HASH | DRBG_STRENGTH256, |
147 | .statelen = 111, /* 888 bits */ |
148 | .blocklen_bytes = 48, |
149 | .cra_name = "sha384", |
150 | .backend_cra_name = "sha384", |
151 | }, { |
152 | .flags = DRBG_HASH | DRBG_STRENGTH256, |
153 | .statelen = 111, /* 888 bits */ |
154 | .blocklen_bytes = 64, |
155 | .cra_name = "sha512", |
156 | .backend_cra_name = "sha512", |
157 | }, { |
158 | .flags = DRBG_HASH | DRBG_STRENGTH256, |
159 | .statelen = 55, /* 440 bits */ |
160 | .blocklen_bytes = 32, |
161 | .cra_name = "sha256", |
162 | .backend_cra_name = "sha256", |
163 | }, |
164 | #endif /* CONFIG_CRYPTO_DRBG_HASH */ |
165 | #ifdef CONFIG_CRYPTO_DRBG_HMAC |
166 | { |
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)", |
172 | }, { |
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)", |
178 | }, { |
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)", |
184 | }, { |
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)", |
190 | }, |
191 | #endif /* CONFIG_CRYPTO_DRBG_HMAC */ |
192 | }; |
193 | |
194 | static int drbg_uninstantiate(struct drbg_state *drbg); |
195 | |
196 | /****************************************************************** |
197 | * Generic helper functions |
198 | ******************************************************************/ |
199 | |
200 | /* |
201 | * Return strength of DRBG according to SP800-90A section 8.4 |
202 | * |
203 | * @flags DRBG flags reference |
204 | * |
205 | * Return: normalized strength in *bytes* value or 32 as default |
206 | * to counter programming errors |
207 | */ |
208 | static inline unsigned short drbg_sec_strength(drbg_flag_t flags) |
209 | { |
210 | switch (flags & DRBG_STRENGTH_MASK) { |
211 | case DRBG_STRENGTH128: |
212 | return 16; |
213 | case DRBG_STRENGTH192: |
214 | return 24; |
215 | case DRBG_STRENGTH256: |
216 | return 32; |
217 | default: |
218 | return 32; |
219 | } |
220 | } |
221 | |
222 | /* |
223 | * Convert an integer into a byte representation of this integer. |
224 | * The byte representation is big-endian |
225 | * |
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 |
229 | */ |
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) |
232 | { |
233 | struct s { |
234 | __be32 conv; |
235 | }; |
236 | struct s *conversion = (struct s *) buf; |
237 | |
238 | conversion->conv = cpu_to_be32(val); |
239 | } |
240 | #endif /* defined(CONFIG_CRYPTO_DRBG_HASH) || defined(CONFIG_CRYPTO_DRBG_CTR) */ |
241 | |
242 | /****************************************************************** |
243 | * CTR DRBG callback functions |
244 | ******************************************************************/ |
245 | |
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"); |
254 | |
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 |
266 | |
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) |
271 | { |
272 | int ret = 0; |
273 | struct drbg_string *curr = NULL; |
274 | struct drbg_string data; |
275 | short cnt = 0; |
276 | |
277 | drbg_string_fill(&data, out, drbg_blocklen(drbg)); |
278 | |
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 */ |
285 | while (len) { |
286 | /* 10.4.3 step 4.2 */ |
287 | if (drbg_blocklen(drbg) == cnt) { |
288 | cnt = 0; |
289 | ret = drbg_kcapi_sym(drbg, out, &data); |
290 | if (ret) |
291 | return ret; |
292 | } |
293 | out[cnt] ^= *pos; |
294 | pos++; |
295 | cnt++; |
296 | len--; |
297 | } |
298 | } |
299 | /* 10.4.3 step 4.2 for last block */ |
300 | if (cnt) |
301 | ret = drbg_kcapi_sym(drbg, out, &data); |
302 | |
303 | return ret; |
304 | } |
305 | |
306 | /* |
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: |
310 | * drbg_ctr_update: |
311 | * temp |
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 |
318 | * memory. |
319 | * df_data |
320 | * start: drbg->scratchpad + |
321 | * drbg_statelen(drbg) + drbg_blocklen(drbg) |
322 | * length: drbg_statelen(drbg) |
323 | * |
324 | * drbg_ctr_df: |
325 | * pad |
326 | * start: df_data + drbg_statelen(drbg) |
327 | * length: drbg_blocklen(drbg) |
328 | * iv |
329 | * start: pad + drbg_blocklen(drbg) |
330 | * length: drbg_blocklen(drbg) |
331 | * temp |
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 |
342 | * possibilities. |
343 | */ |
344 | |
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) |
349 | { |
350 | int ret = -EFAULT; |
351 | unsigned char L_N[8]; |
352 | /* S3 is input */ |
353 | struct drbg_string S1, S2, S4, cipherin; |
354 | LIST_HEAD(bcc_list); |
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); |
358 | size_t padlen = 0; |
359 | unsigned int templen = 0; |
360 | /* 10.4.2 step 7 */ |
361 | unsigned int i = 0; |
362 | /* 10.4.2 step 8 */ |
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"; |
368 | unsigned char *X; |
369 | size_t generated_len = 0; |
370 | size_t inputlen = 0; |
371 | struct drbg_string *seed = NULL; |
372 | |
373 | memset(pad, 0, drbg_blocklen(drbg)); |
374 | memset(iv, 0, drbg_blocklen(drbg)); |
375 | |
376 | /* 10.4.2 step 1 is implicit as we work byte-wise */ |
377 | |
378 | /* 10.4.2 step 2 */ |
379 | if ((512/8) < bytes_to_return) |
380 | return -EINVAL; |
381 | |
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]); |
386 | |
387 | /* 10.4.2 step 3 */ |
388 | drbg_cpu_to_be32(bytes_to_return, &L_N[4]); |
389 | |
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 */ |
393 | if (padlen) |
394 | padlen = drbg_blocklen(drbg) - padlen; |
395 | /* |
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. |
399 | */ |
400 | padlen++; |
401 | pad[0] = 0x80; |
402 | |
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); |
411 | |
412 | /* 10.4.2 step 9 */ |
413 | while (templen < (drbg_keylen(drbg) + (drbg_blocklen(drbg)))) { |
414 | /* |
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 |
418 | */ |
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); |
422 | if (ret) |
423 | goto out; |
424 | /* 10.4.2 step 9.3 */ |
425 | i++; |
426 | templen += drbg_blocklen(drbg); |
427 | } |
428 | |
429 | /* 10.4.2 step 11 */ |
430 | X = temp + (drbg_keylen(drbg)); |
431 | drbg_string_fill(&cipherin, X, drbg_blocklen(drbg)); |
432 | |
433 | /* 10.4.2 step 12: overwriting of outval is implemented in next step */ |
434 | |
435 | /* 10.4.2 step 13 */ |
436 | drbg_kcapi_symsetkey(drbg, temp); |
437 | while (generated_len < bytes_to_return) { |
438 | short blocklen = 0; |
439 | /* |
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 |
443 | */ |
444 | ret = drbg_kcapi_sym(drbg, X, &cipherin); |
445 | if (ret) |
446 | goto out; |
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; |
454 | } |
455 | |
456 | ret = 0; |
457 | |
458 | out: |
459 | memset(iv, 0, drbg_blocklen(drbg)); |
460 | memset(temp, 0, drbg_statelen(drbg) + drbg_blocklen(drbg)); |
461 | memset(pad, 0, drbg_blocklen(drbg)); |
462 | return ret; |
463 | } |
464 | |
465 | /* |
466 | * update function of CTR DRBG as defined in 10.2.1.2 |
467 | * |
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 |
475 | * again. |
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. |
479 | */ |
480 | static int drbg_ctr_update(struct drbg_state *drbg, struct list_head *seed, |
481 | int reseed) |
482 | { |
483 | int ret = -EFAULT; |
484 | /* 10.2.1.2 step 1 */ |
485 | unsigned char *temp = drbg->scratchpad; |
486 | unsigned char *df_data = drbg->scratchpad + drbg_statelen(drbg) + |
487 | drbg_blocklen(drbg); |
488 | |
489 | if (3 > reseed) |
490 | memset(df_data, 0, drbg_statelen(drbg)); |
491 | |
492 | if (!reseed) { |
493 | /* |
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 |
498 | * it by one. |
499 | */ |
500 | crypto_inc(drbg->V, drbg_blocklen(drbg)); |
501 | |
502 | ret = crypto_skcipher_setkey(drbg->ctr_handle, drbg->C, |
503 | drbg_keylen(drbg)); |
504 | if (ret) |
505 | goto out; |
506 | } |
507 | |
508 | /* 10.2.1.3.2 step 2 and 10.2.1.4.2 step 2 */ |
509 | if (seed) { |
510 | ret = drbg_ctr_df(drbg, df_data, drbg_statelen(drbg), seed); |
511 | if (ret) |
512 | goto out; |
513 | } |
514 | |
515 | ret = drbg_kcapi_sym_ctr(drbg, df_data, drbg_statelen(drbg), |
516 | temp, drbg_statelen(drbg)); |
517 | if (ret) |
518 | return ret; |
519 | |
520 | /* 10.2.1.2 step 5 */ |
521 | ret = crypto_skcipher_setkey(drbg->ctr_handle, temp, |
522 | drbg_keylen(drbg)); |
523 | if (ret) |
524 | goto out; |
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)); |
529 | ret = 0; |
530 | |
531 | out: |
532 | memset(temp, 0, drbg_statelen(drbg) + drbg_blocklen(drbg)); |
533 | if (2 != reseed) |
534 | memset(df_data, 0, drbg_statelen(drbg)); |
535 | return ret; |
536 | } |
537 | |
538 | /* |
539 | * scratchpad use: drbg_ctr_update is called independently from |
540 | * drbg_ctr_extract_bytes. Therefore, the scratchpad is reused |
541 | */ |
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) |
546 | { |
547 | int ret; |
548 | int len = min_t(int, buflen, INT_MAX); |
549 | |
550 | /* 10.2.1.5.2 step 2 */ |
551 | if (addtl && !list_empty(addtl)) { |
552 | ret = drbg_ctr_update(drbg, addtl, 2); |
553 | if (ret) |
554 | return 0; |
555 | } |
556 | |
557 | /* 10.2.1.5.2 step 4.1 */ |
558 | ret = drbg_kcapi_sym_ctr(drbg, drbg->ctr_null_value, DRBG_CTR_NULL_LEN, |
559 | buf, len); |
560 | if (ret) |
561 | return ret; |
562 | |
563 | /* 10.2.1.5.2 step 6 */ |
564 | ret = drbg_ctr_update(drbg, NULL, 3); |
565 | if (ret) |
566 | len = ret; |
567 | |
568 | return len; |
569 | } |
570 | |
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, |
576 | }; |
577 | #endif /* CONFIG_CRYPTO_DRBG_CTR */ |
578 | |
579 | /****************************************************************** |
580 | * HMAC DRBG callback functions |
581 | ******************************************************************/ |
582 | |
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) */ |
591 | |
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"); |
602 | |
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, |
605 | int reseed) |
606 | { |
607 | int ret = -EFAULT; |
608 | int i = 0; |
609 | struct drbg_string seed1, seed2, vdata; |
610 | LIST_HEAD(seedlist); |
611 | LIST_HEAD(vdatalist); |
612 | |
613 | if (!reseed) { |
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); |
617 | } |
618 | |
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 */ |
625 | if (seed) |
626 | list_splice_tail(seed, &seedlist); |
627 | |
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; |
633 | if (1 == i) |
634 | prefix = DRBG_PREFIX1; |
635 | /* 10.1.2.2 step 1 and 4 -- concatenation and HMAC for key */ |
636 | seed2.buf = &prefix; |
637 | ret = drbg_kcapi_hash(drbg, drbg->C, &seedlist); |
638 | if (ret) |
639 | return ret; |
640 | drbg_kcapi_hmacsetkey(drbg, drbg->C); |
641 | |
642 | /* 10.1.2.2 step 2 and 5 -- HMAC for V */ |
643 | ret = drbg_kcapi_hash(drbg, drbg->V, &vdatalist); |
644 | if (ret) |
645 | return ret; |
646 | |
647 | /* 10.1.2.2 step 3 */ |
648 | if (!seed) |
649 | return ret; |
650 | } |
651 | |
652 | return 0; |
653 | } |
654 | |
655 | /* generate function of HMAC DRBG as defined in 10.1.2.5 */ |
656 | static int drbg_hmac_generate(struct drbg_state *drbg, |
657 | unsigned char *buf, |
658 | unsigned int buflen, |
659 | struct list_head *addtl) |
660 | { |
661 | int len = 0; |
662 | int ret = 0; |
663 | struct drbg_string data; |
664 | LIST_HEAD(datalist); |
665 | |
666 | /* 10.1.2.5 step 2 */ |
667 | if (addtl && !list_empty(addtl)) { |
668 | ret = drbg_hmac_update(drbg, addtl, 1); |
669 | if (ret) |
670 | return ret; |
671 | } |
672 | |
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); |
679 | if (ret) |
680 | return ret; |
681 | outlen = (drbg_blocklen(drbg) < (buflen - len)) ? |
682 | drbg_blocklen(drbg) : (buflen - len); |
683 | |
684 | /* 10.1.2.5 step 4.2 */ |
685 | memcpy(buf + len, drbg->V, outlen); |
686 | len += outlen; |
687 | } |
688 | |
689 | /* 10.1.2.5 step 6 */ |
690 | if (addtl && !list_empty(addtl)) |
691 | ret = drbg_hmac_update(drbg, addtl, 1); |
692 | else |
693 | ret = drbg_hmac_update(drbg, NULL, 1); |
694 | if (ret) |
695 | return ret; |
696 | |
697 | return len; |
698 | } |
699 | |
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, |
705 | }; |
706 | #endif /* CONFIG_CRYPTO_DRBG_HMAC */ |
707 | |
708 | /****************************************************************** |
709 | * Hash DRBG callback functions |
710 | ******************************************************************/ |
711 | |
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"); |
722 | |
723 | /* |
724 | * Increment buffer |
725 | * |
726 | * @dst buffer to increment |
727 | * @add value to add |
728 | */ |
729 | static inline void drbg_add_buf(unsigned char *dst, size_t dstlen, |
730 | const unsigned char *add, size_t addlen) |
731 | { |
732 | /* implied: dstlen > addlen */ |
733 | unsigned char *dstptr; |
734 | const unsigned char *addptr; |
735 | unsigned int remainder = 0; |
736 | size_t len = addlen; |
737 | |
738 | dstptr = dst + (dstlen-1); |
739 | addptr = add + (addlen-1); |
740 | while (len) { |
741 | remainder += *dstptr + *addptr; |
742 | *dstptr = remainder & 0xff; |
743 | remainder >>= 8; |
744 | len--; dstptr--; addptr--; |
745 | } |
746 | len = dstlen - addlen; |
747 | while (len && remainder > 0) { |
748 | remainder = *dstptr + 1; |
749 | *dstptr = remainder & 0xff; |
750 | remainder >>= 8; |
751 | len--; dstptr--; |
752 | } |
753 | } |
754 | |
755 | /* |
756 | * scratchpad usage: as drbg_hash_update and drbg_hash_df are used |
757 | * interlinked, the scratchpad is used as follows: |
758 | * drbg_hash_update |
759 | * start: drbg->scratchpad |
760 | * length: drbg_statelen(drbg) |
761 | * drbg_hash_df: |
762 | * start: drbg->scratchpad + drbg_statelen(drbg) |
763 | * length: drbg_blocklen(drbg) |
764 | * |
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. |
768 | */ |
769 | |
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) |
774 | { |
775 | int ret = 0; |
776 | size_t len = 0; |
777 | unsigned char input[5]; |
778 | unsigned char *tmp = drbg->scratchpad + drbg_statelen(drbg); |
779 | struct drbg_string data; |
780 | |
781 | /* 10.4.1 step 3 */ |
782 | input[0] = 1; |
783 | drbg_cpu_to_be32((outlen * 8), &input[1]); |
784 | |
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); |
788 | |
789 | /* 10.4.1 step 4 */ |
790 | while (len < outlen) { |
791 | short blocklen = 0; |
792 | /* 10.4.1 step 4.1 */ |
793 | ret = drbg_kcapi_hash(drbg, tmp, entropylist); |
794 | if (ret) |
795 | goto out; |
796 | /* 10.4.1 step 4.2 */ |
797 | input[0]++; |
798 | blocklen = (drbg_blocklen(drbg) < (outlen - len)) ? |
799 | drbg_blocklen(drbg) : (outlen - len); |
800 | memcpy(outval + len, tmp, blocklen); |
801 | len += blocklen; |
802 | } |
803 | |
804 | out: |
805 | memset(tmp, 0, drbg_blocklen(drbg)); |
806 | return ret; |
807 | } |
808 | |
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, |
811 | int reseed) |
812 | { |
813 | int ret = 0; |
814 | struct drbg_string data1, data2; |
815 | LIST_HEAD(datalist); |
816 | LIST_HEAD(datalist2); |
817 | unsigned char *V = drbg->scratchpad; |
818 | unsigned char prefix = DRBG_PREFIX1; |
819 | |
820 | if (!seed) |
821 | return -EINVAL; |
822 | |
823 | if (reseed) { |
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); |
830 | } |
831 | list_splice_tail(seed, &datalist); |
832 | |
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); |
835 | if (ret) |
836 | goto out; |
837 | |
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); |
846 | |
847 | out: |
848 | memset(drbg->scratchpad, 0, drbg_statelen(drbg)); |
849 | return ret; |
850 | } |
851 | |
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) |
855 | { |
856 | int ret = 0; |
857 | struct drbg_string data1, data2; |
858 | LIST_HEAD(datalist); |
859 | unsigned char prefix = DRBG_PREFIX2; |
860 | |
861 | /* 10.1.1.4 step 2 */ |
862 | if (!addtl || list_empty(addtl)) |
863 | return 0; |
864 | |
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); |
872 | if (ret) |
873 | goto out; |
874 | |
875 | /* 10.1.1.4 step 2b */ |
876 | drbg_add_buf(drbg->V, drbg_statelen(drbg), |
877 | drbg->scratchpad, drbg_blocklen(drbg)); |
878 | |
879 | out: |
880 | memset(drbg->scratchpad, 0, drbg_blocklen(drbg)); |
881 | return ret; |
882 | } |
883 | |
884 | /* Hashgen defined in 10.1.1.4 */ |
885 | static int drbg_hash_hashgen(struct drbg_state *drbg, |
886 | unsigned char *buf, |
887 | unsigned int buflen) |
888 | { |
889 | int len = 0; |
890 | int ret = 0; |
891 | unsigned char *src = drbg->scratchpad; |
892 | unsigned char *dst = drbg->scratchpad + drbg_statelen(drbg); |
893 | struct drbg_string data; |
894 | LIST_HEAD(datalist); |
895 | |
896 | /* 10.1.1.4 step hashgen 2 */ |
897 | memcpy(src, drbg->V, drbg_statelen(drbg)); |
898 | |
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); |
905 | if (ret) { |
906 | len = ret; |
907 | goto out; |
908 | } |
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); |
913 | len += outlen; |
914 | /* 10.1.1.4 hashgen step 4.3 */ |
915 | if (len < buflen) |
916 | crypto_inc(src, drbg_statelen(drbg)); |
917 | } |
918 | |
919 | out: |
920 | memset(drbg->scratchpad, 0, |
921 | (drbg_statelen(drbg) + drbg_blocklen(drbg))); |
922 | return len; |
923 | } |
924 | |
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) |
929 | { |
930 | int len = 0; |
931 | int ret = 0; |
932 | union { |
933 | unsigned char req[8]; |
934 | __be64 req_int; |
935 | } u; |
936 | unsigned char prefix = DRBG_PREFIX3; |
937 | struct drbg_string data1, data2; |
938 | LIST_HEAD(datalist); |
939 | |
940 | /* 10.1.1.4 step 2 */ |
941 | ret = drbg_hash_process_addtl(drbg, addtl); |
942 | if (ret) |
943 | return ret; |
944 | /* 10.1.1.4 step 3 */ |
945 | len = drbg_hash_hashgen(drbg, buf, buflen); |
946 | |
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); |
954 | if (ret) { |
955 | len = ret; |
956 | goto out; |
957 | } |
958 | |
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); |
966 | |
967 | out: |
968 | memset(drbg->scratchpad, 0, drbg_blocklen(drbg)); |
969 | return len; |
970 | } |
971 | |
972 | /* |
973 | * scratchpad usage: as update and generate are used isolated, both |
974 | * can use the scratchpad |
975 | */ |
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, |
981 | }; |
982 | #endif /* CONFIG_CRYPTO_DRBG_HASH */ |
983 | |
984 | /****************************************************************** |
985 | * Functions common for DRBG implementations |
986 | ******************************************************************/ |
987 | |
988 | static inline int __drbg_seed(struct drbg_state *drbg, struct list_head *seed, |
989 | int reseed) |
990 | { |
991 | int ret = drbg->d_ops->update(drbg, seed, reseed); |
992 | |
993 | if (ret) |
994 | return ret; |
995 | |
996 | drbg->seeded = true; |
997 | /* 10.1.1.2 / 10.1.1.3 step 5 */ |
998 | drbg->reseed_ctr = 1; |
999 | |
1000 | return ret; |
1001 | } |
1002 | |
1003 | static void drbg_async_seed(struct work_struct *work) |
1004 | { |
1005 | struct drbg_string data; |
1006 | LIST_HEAD(seedlist); |
1007 | struct drbg_state *drbg = container_of(work, struct drbg_state, |
1008 | seed_work); |
1009 | unsigned int entropylen = drbg_sec_strength(drbg->core->flags); |
1010 | unsigned char entropy[32]; |
1011 | |
1012 | BUG_ON(!entropylen); |
1013 | BUG_ON(entropylen > sizeof(entropy)); |
1014 | get_random_bytes(entropy, entropylen); |
1015 | |
1016 | drbg_string_fill(&data, entropy, entropylen); |
1017 | list_add_tail(&data.list, &seedlist); |
1018 | |
1019 | mutex_lock(&drbg->drbg_mutex); |
1020 | |
1021 | /* If nonblocking pool is initialized, deactivate Jitter RNG */ |
1022 | crypto_free_rng(drbg->jent); |
1023 | drbg->jent = NULL; |
1024 | |
1025 | /* Set seeded to false so that if __drbg_seed fails the |
1026 | * next generate call will trigger a reseed. |
1027 | */ |
1028 | drbg->seeded = false; |
1029 | |
1030 | __drbg_seed(drbg, &seedlist, true); |
1031 | |
1032 | if (drbg->seeded) |
1033 | drbg->reseed_threshold = drbg_max_requests(drbg); |
1034 | |
1035 | mutex_unlock(&drbg->drbg_mutex); |
1036 | |
1037 | memzero_explicit(entropy, entropylen); |
1038 | } |
1039 | |
1040 | /* |
1041 | * Seeding or reseeding of the DRBG |
1042 | * |
1043 | * @drbg: DRBG state struct |
1044 | * @pers: personalization / additional information buffer |
1045 | * @reseed: 0 for initial seed process, 1 for reseeding |
1046 | * |
1047 | * return: |
1048 | * 0 on success |
1049 | * error value otherwise |
1050 | */ |
1051 | static int drbg_seed(struct drbg_state *drbg, struct drbg_string *pers, |
1052 | bool reseed) |
1053 | { |
1054 | int ret; |
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); |
1059 | |
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", |
1063 | pers->len); |
1064 | return -EINVAL; |
1065 | } |
1066 | |
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"); |
1071 | } else { |
1072 | /* |
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. |
1079 | */ |
1080 | BUG_ON(!entropylen); |
1081 | if (!reseed) |
1082 | entropylen = ((entropylen + 1) / 2) * 3; |
1083 | BUG_ON((entropylen * 2) > sizeof(entropy)); |
1084 | |
1085 | /* Get seed from in-kernel /dev/urandom */ |
1086 | get_random_bytes(entropy, entropylen); |
1087 | |
1088 | if (!drbg->jent) { |
1089 | drbg_string_fill(&data1, entropy, entropylen); |
1090 | pr_devel("DRBG: (re)seeding with %u bytes of entropy\n", |
1091 | entropylen); |
1092 | } else { |
1093 | /* Get seed from Jitter RNG */ |
1094 | ret = crypto_rng_get_bytes(drbg->jent, |
1095 | entropy + entropylen, |
1096 | entropylen); |
1097 | if (ret) { |
1098 | pr_devel("DRBG: jent failed with %d\n", ret); |
1099 | return ret; |
1100 | } |
1101 | |
1102 | drbg_string_fill(&data1, entropy, entropylen * 2); |
1103 | pr_devel("DRBG: (re)seeding with %u bytes of entropy\n", |
1104 | entropylen * 2); |
1105 | } |
1106 | } |
1107 | list_add_tail(&data1.list, &seedlist); |
1108 | |
1109 | /* |
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 |
1113 | */ |
1114 | if (pers && pers->buf && 0 < pers->len) { |
1115 | list_add_tail(&pers->list, &seedlist); |
1116 | pr_devel("DRBG: using personalization string\n"); |
1117 | } |
1118 | |
1119 | if (!reseed) { |
1120 | memset(drbg->V, 0, drbg_statelen(drbg)); |
1121 | memset(drbg->C, 0, drbg_statelen(drbg)); |
1122 | } |
1123 | |
1124 | ret = __drbg_seed(drbg, &seedlist, reseed); |
1125 | |
1126 | memzero_explicit(entropy, entropylen * 2); |
1127 | |
1128 | return ret; |
1129 | } |
1130 | |
1131 | /* Free all substructures in a DRBG state without the DRBG state structure */ |
1132 | static inline void drbg_dealloc_state(struct drbg_state *drbg) |
1133 | { |
1134 | if (!drbg) |
1135 | return; |
1136 | kzfree(drbg->Vbuf); |
1137 | drbg->Vbuf = NULL; |
1138 | drbg->V = NULL; |
1139 | kzfree(drbg->Cbuf); |
1140 | drbg->Cbuf = NULL; |
1141 | drbg->C = NULL; |
1142 | kzfree(drbg->scratchpadbuf); |
1143 | drbg->scratchpadbuf = NULL; |
1144 | drbg->reseed_ctr = 0; |
1145 | drbg->d_ops = NULL; |
1146 | drbg->core = NULL; |
1147 | } |
1148 | |
1149 | /* |
1150 | * Allocate all sub-structures for a DRBG state. |
1151 | * The DRBG state structure must already be allocated. |
1152 | */ |
1153 | static inline int drbg_alloc_state(struct drbg_state *drbg) |
1154 | { |
1155 | int ret = -ENOMEM; |
1156 | unsigned int sb_size = 0; |
1157 | |
1158 | switch (drbg->core->flags & DRBG_TYPE_MASK) { |
1159 | #ifdef CONFIG_CRYPTO_DRBG_HMAC |
1160 | case DRBG_HMAC: |
1161 | drbg->d_ops = &drbg_hmac_ops; |
1162 | break; |
1163 | #endif /* CONFIG_CRYPTO_DRBG_HMAC */ |
1164 | #ifdef CONFIG_CRYPTO_DRBG_HASH |
1165 | case DRBG_HASH: |
1166 | drbg->d_ops = &drbg_hash_ops; |
1167 | break; |
1168 | #endif /* CONFIG_CRYPTO_DRBG_HASH */ |
1169 | #ifdef CONFIG_CRYPTO_DRBG_CTR |
1170 | case DRBG_CTR: |
1171 | drbg->d_ops = &drbg_ctr_ops; |
1172 | break; |
1173 | #endif /* CONFIG_CRYPTO_DRBG_CTR */ |
1174 | default: |
1175 | ret = -EOPNOTSUPP; |
1176 | goto err; |
1177 | } |
1178 | |
1179 | ret = drbg->d_ops->crypto_init(drbg); |
1180 | if (ret < 0) |
1181 | goto err; |
1182 | |
1183 | drbg->Vbuf = kmalloc(drbg_statelen(drbg) + ret, GFP_KERNEL); |
1184 | if (!drbg->Vbuf) { |
1185 | ret = -ENOMEM; |
1186 | goto fini; |
1187 | } |
1188 | drbg->V = PTR_ALIGN(drbg->Vbuf, ret + 1); |
1189 | drbg->Cbuf = kmalloc(drbg_statelen(drbg) + ret, GFP_KERNEL); |
1190 | if (!drbg->Cbuf) { |
1191 | ret = -ENOMEM; |
1192 | goto fini; |
1193 | } |
1194 | drbg->C = PTR_ALIGN(drbg->Cbuf, ret + 1); |
1195 | /* scratchpad is only generated for CTR and Hash */ |
1196 | if (drbg->core->flags & DRBG_HMAC) |
1197 | sb_size = 0; |
1198 | else if (drbg->core->flags & DRBG_CTR) |
1199 | sb_size = drbg_statelen(drbg) + drbg_blocklen(drbg) + /* temp */ |
1200 | drbg_statelen(drbg) + /* df_data */ |
1201 | drbg_blocklen(drbg) + /* pad */ |
1202 | drbg_blocklen(drbg) + /* iv */ |
1203 | drbg_statelen(drbg) + drbg_blocklen(drbg); /* temp */ |
1204 | else |
1205 | sb_size = drbg_statelen(drbg) + drbg_blocklen(drbg); |
1206 | |
1207 | if (0 < sb_size) { |
1208 | drbg->scratchpadbuf = kzalloc(sb_size + ret, GFP_KERNEL); |
1209 | if (!drbg->scratchpadbuf) { |
1210 | ret = -ENOMEM; |
1211 | goto fini; |
1212 | } |
1213 | drbg->scratchpad = PTR_ALIGN(drbg->scratchpadbuf, ret + 1); |
1214 | } |
1215 | |
1216 | return 0; |
1217 | |
1218 | fini: |
1219 | drbg->d_ops->crypto_fini(drbg); |
1220 | err: |
1221 | drbg_dealloc_state(drbg); |
1222 | return ret; |
1223 | } |
1224 | |
1225 | /************************************************************************* |
1226 | * DRBG interface functions |
1227 | *************************************************************************/ |
1228 | |
1229 | /* |
1230 | * DRBG generate function as required by SP800-90A - this function |
1231 | * generates random numbers |
1232 | * |
1233 | * @drbg DRBG state handle |
1234 | * @buf Buffer where to store the random numbers -- the buffer must already |
1235 | * be pre-allocated by caller |
1236 | * @buflen Length of output buffer - this value defines the number of random |
1237 | * bytes pulled from DRBG |
1238 | * @addtl Additional input that is mixed into state, may be NULL -- note |
1239 | * the entropy is pulled by the DRBG internally unconditionally |
1240 | * as defined in SP800-90A. The additional input is mixed into |
1241 | * the state in addition to the pulled entropy. |
1242 | * |
1243 | * return: 0 when all bytes are generated; < 0 in case of an error |
1244 | */ |
1245 | static int drbg_generate(struct drbg_state *drbg, |
1246 | unsigned char *buf, unsigned int buflen, |
1247 | struct drbg_string *addtl) |
1248 | { |
1249 | int len = 0; |
1250 | LIST_HEAD(addtllist); |
1251 | |
1252 | if (!drbg->core) { |
1253 | pr_devel("DRBG: not yet seeded\n"); |
1254 | return -EINVAL; |
1255 | } |
1256 | if (0 == buflen || !buf) { |
1257 | pr_devel("DRBG: no output buffer provided\n"); |
1258 | return -EINVAL; |
1259 | } |
1260 | if (addtl && NULL == addtl->buf && 0 < addtl->len) { |
1261 | pr_devel("DRBG: wrong format of additional information\n"); |
1262 | return -EINVAL; |
1263 | } |
1264 | |
1265 | /* 9.3.1 step 2 */ |
1266 | len = -EINVAL; |
1267 | if (buflen > (drbg_max_request_bytes(drbg))) { |
1268 | pr_devel("DRBG: requested random numbers too large %u\n", |
1269 | buflen); |
1270 | goto err; |
1271 | } |
1272 | |
1273 | /* 9.3.1 step 3 is implicit with the chosen DRBG */ |
1274 | |
1275 | /* 9.3.1 step 4 */ |
1276 | if (addtl && addtl->len > (drbg_max_addtl(drbg))) { |
1277 | pr_devel("DRBG: additional information string too long %zu\n", |
1278 | addtl->len); |
1279 | goto err; |
1280 | } |
1281 | /* 9.3.1 step 5 is implicit with the chosen DRBG */ |
1282 | |
1283 | /* |
1284 | * 9.3.1 step 6 and 9 supplemented by 9.3.2 step c is implemented |
1285 | * here. The spec is a bit convoluted here, we make it simpler. |
1286 | */ |
1287 | if (drbg->reseed_threshold < drbg->reseed_ctr) |
1288 | drbg->seeded = false; |
1289 | |
1290 | if (drbg->pr || !drbg->seeded) { |
1291 | pr_devel("DRBG: reseeding before generation (prediction " |
1292 | "resistance: %s, state %s)\n", |
1293 | drbg->pr ? "true" : "false", |
1294 | drbg->seeded ? "seeded" : "unseeded"); |
1295 | /* 9.3.1 steps 7.1 through 7.3 */ |
1296 | len = drbg_seed(drbg, addtl, true); |
1297 | if (len) |
1298 | goto err; |
1299 | /* 9.3.1 step 7.4 */ |
1300 | addtl = NULL; |
1301 | } |
1302 | |
1303 | if (addtl && 0 < addtl->len) |
1304 | list_add_tail(&addtl->list, &addtllist); |
1305 | /* 9.3.1 step 8 and 10 */ |
1306 | len = drbg->d_ops->generate(drbg, buf, buflen, &addtllist); |
1307 | |
1308 | /* 10.1.1.4 step 6, 10.1.2.5 step 7, 10.2.1.5.2 step 7 */ |
1309 | drbg->reseed_ctr++; |
1310 | if (0 >= len) |
1311 | goto err; |
1312 | |
1313 | /* |
1314 | * Section 11.3.3 requires to re-perform self tests after some |
1315 | * generated random numbers. The chosen value after which self |
1316 | * test is performed is arbitrary, but it should be reasonable. |
1317 | * However, we do not perform the self tests because of the following |
1318 | * reasons: it is mathematically impossible that the initial self tests |
1319 | * were successfully and the following are not. If the initial would |
1320 | * pass and the following would not, the kernel integrity is violated. |
1321 | * In this case, the entire kernel operation is questionable and it |
1322 | * is unlikely that the integrity violation only affects the |
1323 | * correct operation of the DRBG. |
1324 | * |
1325 | * Albeit the following code is commented out, it is provided in |
1326 | * case somebody has a need to implement the test of 11.3.3. |
1327 | */ |
1328 | #if 0 |
1329 | if (drbg->reseed_ctr && !(drbg->reseed_ctr % 4096)) { |
1330 | int err = 0; |
1331 | pr_devel("DRBG: start to perform self test\n"); |
1332 | if (drbg->core->flags & DRBG_HMAC) |
1333 | err = alg_test("drbg_pr_hmac_sha256", |
1334 | "drbg_pr_hmac_sha256", 0, 0); |
1335 | else if (drbg->core->flags & DRBG_CTR) |
1336 | err = alg_test("drbg_pr_ctr_aes128", |
1337 | "drbg_pr_ctr_aes128", 0, 0); |
1338 | else |
1339 | err = alg_test("drbg_pr_sha256", |
1340 | "drbg_pr_sha256", 0, 0); |
1341 | if (err) { |
1342 | pr_err("DRBG: periodical self test failed\n"); |
1343 | /* |
1344 | * uninstantiate implies that from now on, only errors |
1345 | * are returned when reusing this DRBG cipher handle |
1346 | */ |
1347 | drbg_uninstantiate(drbg); |
1348 | return 0; |
1349 | } else { |
1350 | pr_devel("DRBG: self test successful\n"); |
1351 | } |
1352 | } |
1353 | #endif |
1354 | |
1355 | /* |
1356 | * All operations were successful, return 0 as mandated by |
1357 | * the kernel crypto API interface. |
1358 | */ |
1359 | len = 0; |
1360 | err: |
1361 | return len; |
1362 | } |
1363 | |
1364 | /* |
1365 | * Wrapper around drbg_generate which can pull arbitrary long strings |
1366 | * from the DRBG without hitting the maximum request limitation. |
1367 | * |
1368 | * Parameters: see drbg_generate |
1369 | * Return codes: see drbg_generate -- if one drbg_generate request fails, |
1370 | * the entire drbg_generate_long request fails |
1371 | */ |
1372 | static int drbg_generate_long(struct drbg_state *drbg, |
1373 | unsigned char *buf, unsigned int buflen, |
1374 | struct drbg_string *addtl) |
1375 | { |
1376 | unsigned int len = 0; |
1377 | unsigned int slice = 0; |
1378 | do { |
1379 | int err = 0; |
1380 | unsigned int chunk = 0; |
1381 | slice = ((buflen - len) / drbg_max_request_bytes(drbg)); |
1382 | chunk = slice ? drbg_max_request_bytes(drbg) : (buflen - len); |
1383 | mutex_lock(&drbg->drbg_mutex); |
1384 | err = drbg_generate(drbg, buf + len, chunk, addtl); |
1385 | mutex_unlock(&drbg->drbg_mutex); |
1386 | if (0 > err) |
1387 | return err; |
1388 | len += chunk; |
1389 | } while (slice > 0 && (len < buflen)); |
1390 | return 0; |
1391 | } |
1392 | |
1393 | static void drbg_schedule_async_seed(struct random_ready_callback *rdy) |
1394 | { |
1395 | struct drbg_state *drbg = container_of(rdy, struct drbg_state, |
1396 | random_ready); |
1397 | |
1398 | schedule_work(&drbg->seed_work); |
1399 | } |
1400 | |
1401 | static int drbg_prepare_hrng(struct drbg_state *drbg) |
1402 | { |
1403 | int err; |
1404 | |
1405 | /* We do not need an HRNG in test mode. */ |
1406 | if (list_empty(&drbg->test_data.list)) |
1407 | return 0; |
1408 | |
1409 | INIT_WORK(&drbg->seed_work, drbg_async_seed); |
1410 | |
1411 | drbg->random_ready.owner = THIS_MODULE; |
1412 | drbg->random_ready.func = drbg_schedule_async_seed; |
1413 | |
1414 | err = add_random_ready_callback(&drbg->random_ready); |
1415 | |
1416 | switch (err) { |
1417 | case 0: |
1418 | break; |
1419 | |
1420 | case -EALREADY: |
1421 | err = 0; |
1422 | /* fall through */ |
1423 | |
1424 | default: |
1425 | drbg->random_ready.func = NULL; |
1426 | return err; |
1427 | } |
1428 | |
1429 | drbg->jent = crypto_alloc_rng("jitterentropy_rng", 0, 0); |
1430 | |
1431 | /* |
1432 | * Require frequent reseeds until the seed source is fully |
1433 | * initialized. |
1434 | */ |
1435 | drbg->reseed_threshold = 50; |
1436 | |
1437 | return err; |
1438 | } |
1439 | |
1440 | /* |
1441 | * DRBG instantiation function as required by SP800-90A - this function |
1442 | * sets up the DRBG handle, performs the initial seeding and all sanity |
1443 | * checks required by SP800-90A |
1444 | * |
1445 | * @drbg memory of state -- if NULL, new memory is allocated |
1446 | * @pers Personalization string that is mixed into state, may be NULL -- note |
1447 | * the entropy is pulled by the DRBG internally unconditionally |
1448 | * as defined in SP800-90A. The additional input is mixed into |
1449 | * the state in addition to the pulled entropy. |
1450 | * @coreref reference to core |
1451 | * @pr prediction resistance enabled |
1452 | * |
1453 | * return |
1454 | * 0 on success |
1455 | * error value otherwise |
1456 | */ |
1457 | static int drbg_instantiate(struct drbg_state *drbg, struct drbg_string *pers, |
1458 | int coreref, bool pr) |
1459 | { |
1460 | int ret; |
1461 | bool reseed = true; |
1462 | |
1463 | pr_devel("DRBG: Initializing DRBG core %d with prediction resistance " |
1464 | "%s\n", coreref, pr ? "enabled" : "disabled"); |
1465 | mutex_lock(&drbg->drbg_mutex); |
1466 | |
1467 | /* 9.1 step 1 is implicit with the selected DRBG type */ |
1468 | |
1469 | /* |
1470 | * 9.1 step 2 is implicit as caller can select prediction resistance |
1471 | * and the flag is copied into drbg->flags -- |
1472 | * all DRBG types support prediction resistance |
1473 | */ |
1474 | |
1475 | /* 9.1 step 4 is implicit in drbg_sec_strength */ |
1476 | |
1477 | if (!drbg->core) { |
1478 | drbg->core = &drbg_cores[coreref]; |
1479 | drbg->pr = pr; |
1480 | drbg->seeded = false; |
1481 | drbg->reseed_threshold = drbg_max_requests(drbg); |
1482 | |
1483 | ret = drbg_alloc_state(drbg); |
1484 | if (ret) |
1485 | goto unlock; |
1486 | |
1487 | ret = drbg_prepare_hrng(drbg); |
1488 | if (ret) |
1489 | goto free_everything; |
1490 | |
1491 | if (IS_ERR(drbg->jent)) { |
1492 | ret = PTR_ERR(drbg->jent); |
1493 | drbg->jent = NULL; |
1494 | if (fips_enabled || ret != -ENOENT) |
1495 | goto free_everything; |
1496 | pr_info("DRBG: Continuing without Jitter RNG\n"); |
1497 | } |
1498 | |
1499 | reseed = false; |
1500 | } |
1501 | |
1502 | ret = drbg_seed(drbg, pers, reseed); |
1503 | |
1504 | if (ret && !reseed) |
1505 | goto free_everything; |
1506 | |
1507 | mutex_unlock(&drbg->drbg_mutex); |
1508 | return ret; |
1509 | |
1510 | unlock: |
1511 | mutex_unlock(&drbg->drbg_mutex); |
1512 | return ret; |
1513 | |
1514 | free_everything: |
1515 | mutex_unlock(&drbg->drbg_mutex); |
1516 | drbg_uninstantiate(drbg); |
1517 | return ret; |
1518 | } |
1519 | |
1520 | /* |
1521 | * DRBG uninstantiate function as required by SP800-90A - this function |
1522 | * frees all buffers and the DRBG handle |
1523 | * |
1524 | * @drbg DRBG state handle |
1525 | * |
1526 | * return |
1527 | * 0 on success |
1528 | */ |
1529 | static int drbg_uninstantiate(struct drbg_state *drbg) |
1530 | { |
1531 | if (drbg->random_ready.func) { |
1532 | del_random_ready_callback(&drbg->random_ready); |
1533 | cancel_work_sync(&drbg->seed_work); |
1534 | crypto_free_rng(drbg->jent); |
1535 | drbg->jent = NULL; |
1536 | } |
1537 | |
1538 | if (drbg->d_ops) |
1539 | drbg->d_ops->crypto_fini(drbg); |
1540 | drbg_dealloc_state(drbg); |
1541 | /* no scrubbing of test_data -- this shall survive an uninstantiate */ |
1542 | return 0; |
1543 | } |
1544 | |
1545 | /* |
1546 | * Helper function for setting the test data in the DRBG |
1547 | * |
1548 | * @drbg DRBG state handle |
1549 | * @data test data |
1550 | * @len test data length |
1551 | */ |
1552 | static void drbg_kcapi_set_entropy(struct crypto_rng *tfm, |
1553 | const u8 *data, unsigned int len) |
1554 | { |
1555 | struct drbg_state *drbg = crypto_rng_ctx(tfm); |
1556 | |
1557 | mutex_lock(&drbg->drbg_mutex); |
1558 | drbg_string_fill(&drbg->test_data, data, len); |
1559 | mutex_unlock(&drbg->drbg_mutex); |
1560 | } |
1561 | |
1562 | /*************************************************************** |
1563 | * Kernel crypto API cipher invocations requested by DRBG |
1564 | ***************************************************************/ |
1565 | |
1566 | #if defined(CONFIG_CRYPTO_DRBG_HASH) || defined(CONFIG_CRYPTO_DRBG_HMAC) |
1567 | struct sdesc { |
1568 | struct shash_desc shash; |
1569 | char ctx[]; |
1570 | }; |
1571 | |
1572 | static int drbg_init_hash_kernel(struct drbg_state *drbg) |
1573 | { |
1574 | struct sdesc *sdesc; |
1575 | struct crypto_shash *tfm; |
1576 | |
1577 | tfm = crypto_alloc_shash(drbg->core->backend_cra_name, 0, 0); |
1578 | if (IS_ERR(tfm)) { |
1579 | pr_info("DRBG: could not allocate digest TFM handle: %s\n", |
1580 | drbg->core->backend_cra_name); |
1581 | return PTR_ERR(tfm); |
1582 | } |
1583 | BUG_ON(drbg_blocklen(drbg) != crypto_shash_digestsize(tfm)); |
1584 | sdesc = kzalloc(sizeof(struct shash_desc) + crypto_shash_descsize(tfm), |
1585 | GFP_KERNEL); |
1586 | if (!sdesc) { |
1587 | crypto_free_shash(tfm); |
1588 | return -ENOMEM; |
1589 | } |
1590 | |
1591 | sdesc->shash.tfm = tfm; |
1592 | sdesc->shash.flags = 0; |
1593 | drbg->priv_data = sdesc; |
1594 | |
1595 | return crypto_shash_alignmask(tfm); |
1596 | } |
1597 | |
1598 | static int drbg_fini_hash_kernel(struct drbg_state *drbg) |
1599 | { |
1600 | struct sdesc *sdesc = (struct sdesc *)drbg->priv_data; |
1601 | if (sdesc) { |
1602 | crypto_free_shash(sdesc->shash.tfm); |
1603 | kzfree(sdesc); |
1604 | } |
1605 | drbg->priv_data = NULL; |
1606 | return 0; |
1607 | } |
1608 | |
1609 | static void drbg_kcapi_hmacsetkey(struct drbg_state *drbg, |
1610 | const unsigned char *key) |
1611 | { |
1612 | struct sdesc *sdesc = (struct sdesc *)drbg->priv_data; |
1613 | |
1614 | crypto_shash_setkey(sdesc->shash.tfm, key, drbg_statelen(drbg)); |
1615 | } |
1616 | |
1617 | static int drbg_kcapi_hash(struct drbg_state *drbg, unsigned char *outval, |
1618 | const struct list_head *in) |
1619 | { |
1620 | struct sdesc *sdesc = (struct sdesc *)drbg->priv_data; |
1621 | struct drbg_string *input = NULL; |
1622 | |
1623 | crypto_shash_init(&sdesc->shash); |
1624 | list_for_each_entry(input, in, list) |
1625 | crypto_shash_update(&sdesc->shash, input->buf, input->len); |
1626 | return crypto_shash_final(&sdesc->shash, outval); |
1627 | } |
1628 | #endif /* (CONFIG_CRYPTO_DRBG_HASH || CONFIG_CRYPTO_DRBG_HMAC) */ |
1629 | |
1630 | #ifdef CONFIG_CRYPTO_DRBG_CTR |
1631 | static int drbg_fini_sym_kernel(struct drbg_state *drbg) |
1632 | { |
1633 | struct crypto_cipher *tfm = |
1634 | (struct crypto_cipher *)drbg->priv_data; |
1635 | if (tfm) |
1636 | crypto_free_cipher(tfm); |
1637 | drbg->priv_data = NULL; |
1638 | |
1639 | if (drbg->ctr_handle) |
1640 | crypto_free_skcipher(drbg->ctr_handle); |
1641 | drbg->ctr_handle = NULL; |
1642 | |
1643 | if (drbg->ctr_req) |
1644 | skcipher_request_free(drbg->ctr_req); |
1645 | drbg->ctr_req = NULL; |
1646 | |
1647 | kfree(drbg->ctr_null_value_buf); |
1648 | drbg->ctr_null_value = NULL; |
1649 | |
1650 | kfree(drbg->outscratchpadbuf); |
1651 | drbg->outscratchpadbuf = NULL; |
1652 | |
1653 | return 0; |
1654 | } |
1655 | |
1656 | static void drbg_skcipher_cb(struct crypto_async_request *req, int error) |
1657 | { |
1658 | struct drbg_state *drbg = req->data; |
1659 | |
1660 | if (error == -EINPROGRESS) |
1661 | return; |
1662 | drbg->ctr_async_err = error; |
1663 | complete(&drbg->ctr_completion); |
1664 | } |
1665 | |
1666 | static int drbg_init_sym_kernel(struct drbg_state *drbg) |
1667 | { |
1668 | struct crypto_cipher *tfm; |
1669 | struct crypto_skcipher *sk_tfm; |
1670 | struct skcipher_request *req; |
1671 | unsigned int alignmask; |
1672 | char ctr_name[CRYPTO_MAX_ALG_NAME]; |
1673 | |
1674 | tfm = crypto_alloc_cipher(drbg->core->backend_cra_name, 0, 0); |
1675 | if (IS_ERR(tfm)) { |
1676 | pr_info("DRBG: could not allocate cipher TFM handle: %s\n", |
1677 | drbg->core->backend_cra_name); |
1678 | return PTR_ERR(tfm); |
1679 | } |
1680 | BUG_ON(drbg_blocklen(drbg) != crypto_cipher_blocksize(tfm)); |
1681 | drbg->priv_data = tfm; |
1682 | |
1683 | if (snprintf(ctr_name, CRYPTO_MAX_ALG_NAME, "ctr(%s)", |
1684 | drbg->core->backend_cra_name) >= CRYPTO_MAX_ALG_NAME) { |
1685 | drbg_fini_sym_kernel(drbg); |
1686 | return -EINVAL; |
1687 | } |
1688 | sk_tfm = crypto_alloc_skcipher(ctr_name, 0, 0); |
1689 | if (IS_ERR(sk_tfm)) { |
1690 | pr_info("DRBG: could not allocate CTR cipher TFM handle: %s\n", |
1691 | ctr_name); |
1692 | drbg_fini_sym_kernel(drbg); |
1693 | return PTR_ERR(sk_tfm); |
1694 | } |
1695 | drbg->ctr_handle = sk_tfm; |
1696 | init_completion(&drbg->ctr_completion); |
1697 | |
1698 | req = skcipher_request_alloc(sk_tfm, GFP_KERNEL); |
1699 | if (!req) { |
1700 | pr_info("DRBG: could not allocate request queue\n"); |
1701 | drbg_fini_sym_kernel(drbg); |
1702 | return -ENOMEM; |
1703 | } |
1704 | drbg->ctr_req = req; |
1705 | skcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG, |
1706 | drbg_skcipher_cb, drbg); |
1707 | |
1708 | alignmask = crypto_skcipher_alignmask(sk_tfm); |
1709 | drbg->ctr_null_value_buf = kzalloc(DRBG_CTR_NULL_LEN + alignmask, |
1710 | GFP_KERNEL); |
1711 | if (!drbg->ctr_null_value_buf) { |
1712 | drbg_fini_sym_kernel(drbg); |
1713 | return -ENOMEM; |
1714 | } |
1715 | drbg->ctr_null_value = (u8 *)PTR_ALIGN(drbg->ctr_null_value_buf, |
1716 | alignmask + 1); |
1717 | |
1718 | drbg->outscratchpadbuf = kmalloc(DRBG_OUTSCRATCHLEN + alignmask, |
1719 | GFP_KERNEL); |
1720 | if (!drbg->outscratchpadbuf) { |
1721 | drbg_fini_sym_kernel(drbg); |
1722 | return -ENOMEM; |
1723 | } |
1724 | drbg->outscratchpad = (u8 *)PTR_ALIGN(drbg->outscratchpadbuf, |
1725 | alignmask + 1); |
1726 | |
1727 | return alignmask; |
1728 | } |
1729 | |
1730 | static void drbg_kcapi_symsetkey(struct drbg_state *drbg, |
1731 | const unsigned char *key) |
1732 | { |
1733 | struct crypto_cipher *tfm = |
1734 | (struct crypto_cipher *)drbg->priv_data; |
1735 | |
1736 | crypto_cipher_setkey(tfm, key, (drbg_keylen(drbg))); |
1737 | } |
1738 | |
1739 | static int drbg_kcapi_sym(struct drbg_state *drbg, unsigned char *outval, |
1740 | const struct drbg_string *in) |
1741 | { |
1742 | struct crypto_cipher *tfm = |
1743 | (struct crypto_cipher *)drbg->priv_data; |
1744 | |
1745 | /* there is only component in *in */ |
1746 | BUG_ON(in->len < drbg_blocklen(drbg)); |
1747 | crypto_cipher_encrypt_one(tfm, outval, in->buf); |
1748 | return 0; |
1749 | } |
1750 | |
1751 | static int drbg_kcapi_sym_ctr(struct drbg_state *drbg, |
1752 | u8 *inbuf, u32 inlen, |
1753 | u8 *outbuf, u32 outlen) |
1754 | { |
1755 | struct scatterlist sg_in; |
1756 | int ret; |
1757 | |
1758 | sg_init_one(&sg_in, inbuf, inlen); |
1759 | |
1760 | while (outlen) { |
1761 | u32 cryptlen = min3(inlen, outlen, (u32)DRBG_OUTSCRATCHLEN); |
1762 | struct scatterlist sg_out; |
1763 | |
1764 | /* Output buffer may not be valid for SGL, use scratchpad */ |
1765 | sg_init_one(&sg_out, drbg->outscratchpad, cryptlen); |
1766 | skcipher_request_set_crypt(drbg->ctr_req, &sg_in, &sg_out, |
1767 | cryptlen, drbg->V); |
1768 | ret = crypto_skcipher_encrypt(drbg->ctr_req); |
1769 | switch (ret) { |
1770 | case 0: |
1771 | break; |
1772 | case -EINPROGRESS: |
1773 | case -EBUSY: |
1774 | wait_for_completion(&drbg->ctr_completion); |
1775 | if (!drbg->ctr_async_err) { |
1776 | reinit_completion(&drbg->ctr_completion); |
1777 | break; |
1778 | } |
1779 | default: |
1780 | goto out; |
1781 | } |
1782 | init_completion(&drbg->ctr_completion); |
1783 | |
1784 | memcpy(outbuf, drbg->outscratchpad, cryptlen); |
1785 | |
1786 | outlen -= cryptlen; |
1787 | } |
1788 | ret = 0; |
1789 | |
1790 | out: |
1791 | memzero_explicit(drbg->outscratchpad, DRBG_OUTSCRATCHLEN); |
1792 | return ret; |
1793 | } |
1794 | #endif /* CONFIG_CRYPTO_DRBG_CTR */ |
1795 | |
1796 | /*************************************************************** |
1797 | * Kernel crypto API interface to register DRBG |
1798 | ***************************************************************/ |
1799 | |
1800 | /* |
1801 | * Look up the DRBG flags by given kernel crypto API cra_name |
1802 | * The code uses the drbg_cores definition to do this |
1803 | * |
1804 | * @cra_name kernel crypto API cra_name |
1805 | * @coreref reference to integer which is filled with the pointer to |
1806 | * the applicable core |
1807 | * @pr reference for setting prediction resistance |
1808 | * |
1809 | * return: flags |
1810 | */ |
1811 | static inline void drbg_convert_tfm_core(const char *cra_driver_name, |
1812 | int *coreref, bool *pr) |
1813 | { |
1814 | int i = 0; |
1815 | size_t start = 0; |
1816 | int len = 0; |
1817 | |
1818 | *pr = true; |
1819 | /* disassemble the names */ |
1820 | if (!memcmp(cra_driver_name, "drbg_nopr_", 10)) { |
1821 | start = 10; |
1822 | *pr = false; |
1823 | } else if (!memcmp(cra_driver_name, "drbg_pr_", 8)) { |
1824 | start = 8; |
1825 | } else { |
1826 | return; |
1827 | } |
1828 | |
1829 | /* remove the first part */ |
1830 | len = strlen(cra_driver_name) - start; |
1831 | for (i = 0; ARRAY_SIZE(drbg_cores) > i; i++) { |
1832 | if (!memcmp(cra_driver_name + start, drbg_cores[i].cra_name, |
1833 | len)) { |
1834 | *coreref = i; |
1835 | return; |
1836 | } |
1837 | } |
1838 | } |
1839 | |
1840 | static int drbg_kcapi_init(struct crypto_tfm *tfm) |
1841 | { |
1842 | struct drbg_state *drbg = crypto_tfm_ctx(tfm); |
1843 | |
1844 | mutex_init(&drbg->drbg_mutex); |
1845 | |
1846 | return 0; |
1847 | } |
1848 | |
1849 | static void drbg_kcapi_cleanup(struct crypto_tfm *tfm) |
1850 | { |
1851 | drbg_uninstantiate(crypto_tfm_ctx(tfm)); |
1852 | } |
1853 | |
1854 | /* |
1855 | * Generate random numbers invoked by the kernel crypto API: |
1856 | * The API of the kernel crypto API is extended as follows: |
1857 | * |
1858 | * src is additional input supplied to the RNG. |
1859 | * slen is the length of src. |
1860 | * dst is the output buffer where random data is to be stored. |
1861 | * dlen is the length of dst. |
1862 | */ |
1863 | static int drbg_kcapi_random(struct crypto_rng *tfm, |
1864 | const u8 *src, unsigned int slen, |
1865 | u8 *dst, unsigned int dlen) |
1866 | { |
1867 | struct drbg_state *drbg = crypto_rng_ctx(tfm); |
1868 | struct drbg_string *addtl = NULL; |
1869 | struct drbg_string string; |
1870 | |
1871 | if (slen) { |
1872 | /* linked list variable is now local to allow modification */ |
1873 | drbg_string_fill(&string, src, slen); |
1874 | addtl = &string; |
1875 | } |
1876 | |
1877 | return drbg_generate_long(drbg, dst, dlen, addtl); |
1878 | } |
1879 | |
1880 | /* |
1881 | * Seed the DRBG invoked by the kernel crypto API |
1882 | */ |
1883 | static int drbg_kcapi_seed(struct crypto_rng *tfm, |
1884 | const u8 *seed, unsigned int slen) |
1885 | { |
1886 | struct drbg_state *drbg = crypto_rng_ctx(tfm); |
1887 | struct crypto_tfm *tfm_base = crypto_rng_tfm(tfm); |
1888 | bool pr = false; |
1889 | struct drbg_string string; |
1890 | struct drbg_string *seed_string = NULL; |
1891 | int coreref = 0; |
1892 | |
1893 | drbg_convert_tfm_core(crypto_tfm_alg_driver_name(tfm_base), &coreref, |
1894 | &pr); |
1895 | if (0 < slen) { |
1896 | drbg_string_fill(&string, seed, slen); |
1897 | seed_string = &string; |
1898 | } |
1899 | |
1900 | return drbg_instantiate(drbg, seed_string, coreref, pr); |
1901 | } |
1902 | |
1903 | /*************************************************************** |
1904 | * Kernel module: code to load the module |
1905 | ***************************************************************/ |
1906 | |
1907 | /* |
1908 | * Tests as defined in 11.3.2 in addition to the cipher tests: testing |
1909 | * of the error handling. |
1910 | * |
1911 | * Note: testing of failing seed source as defined in 11.3.2 is not applicable |
1912 | * as seed source of get_random_bytes does not fail. |
1913 | * |
1914 | * Note 2: There is no sensible way of testing the reseed counter |
1915 | * enforcement, so skip it. |
1916 | */ |
1917 | static inline int __init drbg_healthcheck_sanity(void) |
1918 | { |
1919 | int len = 0; |
1920 | #define OUTBUFLEN 16 |
1921 | unsigned char buf[OUTBUFLEN]; |
1922 | struct drbg_state *drbg = NULL; |
1923 | int ret = -EFAULT; |
1924 | int rc = -EFAULT; |
1925 | bool pr = false; |
1926 | int coreref = 0; |
1927 | struct drbg_string addtl; |
1928 | size_t max_addtllen, max_request_bytes; |
1929 | |
1930 | /* only perform test in FIPS mode */ |
1931 | if (!fips_enabled) |
1932 | return 0; |
1933 | |
1934 | #ifdef CONFIG_CRYPTO_DRBG_CTR |
1935 | drbg_convert_tfm_core("drbg_nopr_ctr_aes128", &coreref, &pr); |
1936 | #elif defined CONFIG_CRYPTO_DRBG_HASH |
1937 | drbg_convert_tfm_core("drbg_nopr_sha256", &coreref, &pr); |
1938 | #else |
1939 | drbg_convert_tfm_core("drbg_nopr_hmac_sha256", &coreref, &pr); |
1940 | #endif |
1941 | |
1942 | drbg = kzalloc(sizeof(struct drbg_state), GFP_KERNEL); |
1943 | if (!drbg) |
1944 | return -ENOMEM; |
1945 | |
1946 | mutex_init(&drbg->drbg_mutex); |
1947 | drbg->core = &drbg_cores[coreref]; |
1948 | drbg->reseed_threshold = drbg_max_requests(drbg); |
1949 | |
1950 | /* |
1951 | * if the following tests fail, it is likely that there is a buffer |
1952 | * overflow as buf is much smaller than the requested or provided |
1953 | * string lengths -- in case the error handling does not succeed |
1954 | * we may get an OOPS. And we want to get an OOPS as this is a |
1955 | * grave bug. |
1956 | */ |
1957 | |
1958 | max_addtllen = drbg_max_addtl(drbg); |
1959 | max_request_bytes = drbg_max_request_bytes(drbg); |
1960 | drbg_string_fill(&addtl, buf, max_addtllen + 1); |
1961 | /* overflow addtllen with additonal info string */ |
1962 | len = drbg_generate(drbg, buf, OUTBUFLEN, &addtl); |
1963 | BUG_ON(0 < len); |
1964 | /* overflow max_bits */ |
1965 | len = drbg_generate(drbg, buf, (max_request_bytes + 1), NULL); |
1966 | BUG_ON(0 < len); |
1967 | |
1968 | /* overflow max addtllen with personalization string */ |
1969 | ret = drbg_seed(drbg, &addtl, false); |
1970 | BUG_ON(0 == ret); |
1971 | /* all tests passed */ |
1972 | rc = 0; |
1973 | |
1974 | pr_devel("DRBG: Sanity tests for failure code paths successfully " |
1975 | "completed\n"); |
1976 | |
1977 | kfree(drbg); |
1978 | return rc; |
1979 | } |
1980 | |
1981 | static struct rng_alg drbg_algs[22]; |
1982 | |
1983 | /* |
1984 | * Fill the array drbg_algs used to register the different DRBGs |
1985 | * with the kernel crypto API. To fill the array, the information |
1986 | * from drbg_cores[] is used. |
1987 | */ |
1988 | static inline void __init drbg_fill_array(struct rng_alg *alg, |
1989 | const struct drbg_core *core, int pr) |
1990 | { |
1991 | int pos = 0; |
1992 | static int priority = 200; |
1993 | |
1994 | memcpy(alg->base.cra_name, "stdrng", 6); |
1995 | if (pr) { |
1996 | memcpy(alg->base.cra_driver_name, "drbg_pr_", 8); |
1997 | pos = 8; |
1998 | } else { |
1999 | memcpy(alg->base.cra_driver_name, "drbg_nopr_", 10); |
2000 | pos = 10; |
2001 | } |
2002 | memcpy(alg->base.cra_driver_name + pos, core->cra_name, |
2003 | strlen(core->cra_name)); |
2004 | |
2005 | alg->base.cra_priority = priority; |
2006 | priority++; |
2007 | /* |
2008 | * If FIPS mode enabled, the selected DRBG shall have the |
2009 | * highest cra_priority over other stdrng instances to ensure |
2010 | * it is selected. |
2011 | */ |
2012 | if (fips_enabled) |
2013 | alg->base.cra_priority += 200; |
2014 | |
2015 | alg->base.cra_ctxsize = sizeof(struct drbg_state); |
2016 | alg->base.cra_module = THIS_MODULE; |
2017 | alg->base.cra_init = drbg_kcapi_init; |
2018 | alg->base.cra_exit = drbg_kcapi_cleanup; |
2019 | alg->generate = drbg_kcapi_random; |
2020 | alg->seed = drbg_kcapi_seed; |
2021 | alg->set_ent = drbg_kcapi_set_entropy; |
2022 | alg->seedsize = 0; |
2023 | } |
2024 | |
2025 | static int __init drbg_init(void) |
2026 | { |
2027 | unsigned int i = 0; /* pointer to drbg_algs */ |
2028 | unsigned int j = 0; /* pointer to drbg_cores */ |
2029 | int ret; |
2030 | |
2031 | ret = drbg_healthcheck_sanity(); |
2032 | if (ret) |
2033 | return ret; |
2034 | |
2035 | if (ARRAY_SIZE(drbg_cores) * 2 > ARRAY_SIZE(drbg_algs)) { |
2036 | pr_info("DRBG: Cannot register all DRBG types" |
2037 | "(slots needed: %zu, slots available: %zu)\n", |
2038 | ARRAY_SIZE(drbg_cores) * 2, ARRAY_SIZE(drbg_algs)); |
2039 | return -EFAULT; |
2040 | } |
2041 | |
2042 | /* |
2043 | * each DRBG definition can be used with PR and without PR, thus |
2044 | * we instantiate each DRBG in drbg_cores[] twice. |
2045 | * |
2046 | * As the order of placing them into the drbg_algs array matters |
2047 | * (the later DRBGs receive a higher cra_priority) we register the |
2048 | * prediction resistance DRBGs first as the should not be too |
2049 | * interesting. |
2050 | */ |
2051 | for (j = 0; ARRAY_SIZE(drbg_cores) > j; j++, i++) |
2052 | drbg_fill_array(&drbg_algs[i], &drbg_cores[j], 1); |
2053 | for (j = 0; ARRAY_SIZE(drbg_cores) > j; j++, i++) |
2054 | drbg_fill_array(&drbg_algs[i], &drbg_cores[j], 0); |
2055 | return crypto_register_rngs(drbg_algs, (ARRAY_SIZE(drbg_cores) * 2)); |
2056 | } |
2057 | |
2058 | static void __exit drbg_exit(void) |
2059 | { |
2060 | crypto_unregister_rngs(drbg_algs, (ARRAY_SIZE(drbg_cores) * 2)); |
2061 | } |
2062 | |
2063 | module_init(drbg_init); |
2064 | module_exit(drbg_exit); |
2065 | #ifndef CRYPTO_DRBG_HASH_STRING |
2066 | #define CRYPTO_DRBG_HASH_STRING "" |
2067 | #endif |
2068 | #ifndef CRYPTO_DRBG_HMAC_STRING |
2069 | #define CRYPTO_DRBG_HMAC_STRING "" |
2070 | #endif |
2071 | #ifndef CRYPTO_DRBG_CTR_STRING |
2072 | #define CRYPTO_DRBG_CTR_STRING "" |
2073 | #endif |
2074 | MODULE_LICENSE("GPL"); |
2075 | MODULE_AUTHOR("Stephan Mueller <smueller@chronox.de>"); |
2076 | MODULE_DESCRIPTION("NIST SP800-90A Deterministic Random Bit Generator (DRBG) " |
2077 | "using following cores: " |
2078 | CRYPTO_DRBG_HASH_STRING |
2079 | CRYPTO_DRBG_HMAC_STRING |
2080 | CRYPTO_DRBG_CTR_STRING); |
2081 | MODULE_ALIAS_CRYPTO("stdrng"); |
2082 |