forked from grate-driver/linux
-
Notifications
You must be signed in to change notification settings - Fork 0
/
drbg.c
2063 lines (1820 loc) · 57.2 KB
/
drbg.c
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
/*
* DRBG: Deterministic Random Bits Generator
* Based on NIST Recommended DRBG from NIST SP800-90A with the following
* properties:
* * CTR DRBG with DF with AES-128, AES-192, AES-256 cores
* * Hash DRBG with DF with SHA-1, SHA-256, SHA-384, SHA-512 cores
* * HMAC DRBG with DF with SHA-1, SHA-256, SHA-384, SHA-512 cores
* * with and without prediction resistance
*
* Copyright Stephan Mueller <smueller@chronox.de>, 2014
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, and the entire permission notice in its entirety,
* including the disclaimer of warranties.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote
* products derived from this software without specific prior
* written permission.
*
* ALTERNATIVELY, this product may be distributed under the terms of
* the GNU General Public License, in which case the provisions of the GPL are
* required INSTEAD OF the above restrictions. (This clause is
* necessary due to a potential bad interaction between the GPL and
* the restrictions contained in a BSD-style copyright.)
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, ALL OF
* WHICH ARE HEREBY DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
* OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
* BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
* USE OF THIS SOFTWARE, EVEN IF NOT ADVISED OF THE POSSIBILITY OF SUCH
* DAMAGE.
*
* DRBG Usage
* ==========
* The SP 800-90A DRBG allows the user to specify a personalization string
* for initialization as well as an additional information string for each
* random number request. The following code fragments show how a caller
* uses the kernel crypto API to use the full functionality of the DRBG.
*
* Usage without any additional data
* ---------------------------------
* struct crypto_rng *drng;
* int err;
* char data[DATALEN];
*
* drng = crypto_alloc_rng(drng_name, 0, 0);
* err = crypto_rng_get_bytes(drng, &data, DATALEN);
* crypto_free_rng(drng);
*
*
* Usage with personalization string during initialization
* -------------------------------------------------------
* struct crypto_rng *drng;
* int err;
* char data[DATALEN];
* struct drbg_string pers;
* char personalization[11] = "some-string";
*
* drbg_string_fill(&pers, personalization, strlen(personalization));
* drng = crypto_alloc_rng(drng_name, 0, 0);
* // The reset completely re-initializes the DRBG with the provided
* // personalization string
* err = crypto_rng_reset(drng, &personalization, strlen(personalization));
* err = crypto_rng_get_bytes(drng, &data, DATALEN);
* crypto_free_rng(drng);
*
*
* Usage with additional information string during random number request
* ---------------------------------------------------------------------
* struct crypto_rng *drng;
* int err;
* char data[DATALEN];
* char addtl_string[11] = "some-string";
* string drbg_string addtl;
*
* drbg_string_fill(&addtl, addtl_string, strlen(addtl_string));
* drng = crypto_alloc_rng(drng_name, 0, 0);
* // The following call is a wrapper to crypto_rng_get_bytes() and returns
* // the same error codes.
* err = crypto_drbg_get_bytes_addtl(drng, &data, DATALEN, &addtl);
* crypto_free_rng(drng);
*
*
* Usage with personalization and additional information strings
* -------------------------------------------------------------
* Just mix both scenarios above.
*/
#include <crypto/drbg.h>
#include <linux/kernel.h>
/***************************************************************
* Backend cipher definitions available to DRBG
***************************************************************/
/*
* The order of the DRBG definitions here matter: every DRBG is registered
* as stdrng. Each DRBG receives an increasing cra_priority values the later
* they are defined in this array (see drbg_fill_array).
*
* HMAC DRBGs are favored over Hash DRBGs over CTR DRBGs, and
* the SHA256 / AES 256 over other ciphers. Thus, the favored
* DRBGs are the latest entries in this array.
*/
static const struct drbg_core drbg_cores[] = {
#ifdef CONFIG_CRYPTO_DRBG_CTR
{
.flags = DRBG_CTR | DRBG_STRENGTH128,
.statelen = 32, /* 256 bits as defined in 10.2.1 */
.blocklen_bytes = 16,
.cra_name = "ctr_aes128",
.backend_cra_name = "aes",
}, {
.flags = DRBG_CTR | DRBG_STRENGTH192,
.statelen = 40, /* 320 bits as defined in 10.2.1 */
.blocklen_bytes = 16,
.cra_name = "ctr_aes192",
.backend_cra_name = "aes",
}, {
.flags = DRBG_CTR | DRBG_STRENGTH256,
.statelen = 48, /* 384 bits as defined in 10.2.1 */
.blocklen_bytes = 16,
.cra_name = "ctr_aes256",
.backend_cra_name = "aes",
},
#endif /* CONFIG_CRYPTO_DRBG_CTR */
#ifdef CONFIG_CRYPTO_DRBG_HASH
{
.flags = DRBG_HASH | DRBG_STRENGTH128,
.statelen = 55, /* 440 bits */
.blocklen_bytes = 20,
.cra_name = "sha1",
.backend_cra_name = "sha1",
}, {
.flags = DRBG_HASH | DRBG_STRENGTH256,
.statelen = 111, /* 888 bits */
.blocklen_bytes = 48,
.cra_name = "sha384",
.backend_cra_name = "sha384",
}, {
.flags = DRBG_HASH | DRBG_STRENGTH256,
.statelen = 111, /* 888 bits */
.blocklen_bytes = 64,
.cra_name = "sha512",
.backend_cra_name = "sha512",
}, {
.flags = DRBG_HASH | DRBG_STRENGTH256,
.statelen = 55, /* 440 bits */
.blocklen_bytes = 32,
.cra_name = "sha256",
.backend_cra_name = "sha256",
},
#endif /* CONFIG_CRYPTO_DRBG_HASH */
#ifdef CONFIG_CRYPTO_DRBG_HMAC
{
.flags = DRBG_HMAC | DRBG_STRENGTH128,
.statelen = 20, /* block length of cipher */
.blocklen_bytes = 20,
.cra_name = "hmac_sha1",
.backend_cra_name = "hmac(sha1)",
}, {
.flags = DRBG_HMAC | DRBG_STRENGTH256,
.statelen = 48, /* block length of cipher */
.blocklen_bytes = 48,
.cra_name = "hmac_sha384",
.backend_cra_name = "hmac(sha384)",
}, {
.flags = DRBG_HMAC | DRBG_STRENGTH256,
.statelen = 64, /* block length of cipher */
.blocklen_bytes = 64,
.cra_name = "hmac_sha512",
.backend_cra_name = "hmac(sha512)",
}, {
.flags = DRBG_HMAC | DRBG_STRENGTH256,
.statelen = 32, /* block length of cipher */
.blocklen_bytes = 32,
.cra_name = "hmac_sha256",
.backend_cra_name = "hmac(sha256)",
},
#endif /* CONFIG_CRYPTO_DRBG_HMAC */
};
static int drbg_uninstantiate(struct drbg_state *drbg);
/******************************************************************
* Generic helper functions
******************************************************************/
/*
* Return strength of DRBG according to SP800-90A section 8.4
*
* @flags DRBG flags reference
*
* Return: normalized strength in *bytes* value or 32 as default
* to counter programming errors
*/
static inline unsigned short drbg_sec_strength(drbg_flag_t flags)
{
switch (flags & DRBG_STRENGTH_MASK) {
case DRBG_STRENGTH128:
return 16;
case DRBG_STRENGTH192:
return 24;
case DRBG_STRENGTH256:
return 32;
default:
return 32;
}
}
/*
* Convert an integer into a byte representation of this integer.
* The byte representation is big-endian
*
* @val value to be converted
* @buf buffer holding the converted integer -- caller must ensure that
* buffer size is at least 32 bit
*/
#if (defined(CONFIG_CRYPTO_DRBG_HASH) || defined(CONFIG_CRYPTO_DRBG_CTR))
static inline void drbg_cpu_to_be32(__u32 val, unsigned char *buf)
{
struct s {
__be32 conv;
};
struct s *conversion = (struct s *) buf;
conversion->conv = cpu_to_be32(val);
}
#endif /* defined(CONFIG_CRYPTO_DRBG_HASH) || defined(CONFIG_CRYPTO_DRBG_CTR) */
/******************************************************************
* CTR DRBG callback functions
******************************************************************/
#ifdef CONFIG_CRYPTO_DRBG_CTR
#define CRYPTO_DRBG_CTR_STRING "CTR "
MODULE_ALIAS_CRYPTO("drbg_pr_ctr_aes256");
MODULE_ALIAS_CRYPTO("drbg_nopr_ctr_aes256");
MODULE_ALIAS_CRYPTO("drbg_pr_ctr_aes192");
MODULE_ALIAS_CRYPTO("drbg_nopr_ctr_aes192");
MODULE_ALIAS_CRYPTO("drbg_pr_ctr_aes128");
MODULE_ALIAS_CRYPTO("drbg_nopr_ctr_aes128");
static void drbg_kcapi_symsetkey(struct drbg_state *drbg,
const unsigned char *key);
static int drbg_kcapi_sym(struct drbg_state *drbg, unsigned char *outval,
const struct drbg_string *in);
static int drbg_init_sym_kernel(struct drbg_state *drbg);
static int drbg_fini_sym_kernel(struct drbg_state *drbg);
static int drbg_kcapi_sym_ctr(struct drbg_state *drbg,
u8 *inbuf, u32 inbuflen,
u8 *outbuf, u32 outlen);
#define DRBG_CTR_NULL_LEN 128
#define DRBG_OUTSCRATCHLEN DRBG_CTR_NULL_LEN
/* BCC function for CTR DRBG as defined in 10.4.3 */
static int drbg_ctr_bcc(struct drbg_state *drbg,
unsigned char *out, const unsigned char *key,
struct list_head *in)
{
int ret = 0;
struct drbg_string *curr = NULL;
struct drbg_string data;
short cnt = 0;
drbg_string_fill(&data, out, drbg_blocklen(drbg));
/* 10.4.3 step 2 / 4 */
drbg_kcapi_symsetkey(drbg, key);
list_for_each_entry(curr, in, list) {
const unsigned char *pos = curr->buf;
size_t len = curr->len;
/* 10.4.3 step 4.1 */
while (len) {
/* 10.4.3 step 4.2 */
if (drbg_blocklen(drbg) == cnt) {
cnt = 0;
ret = drbg_kcapi_sym(drbg, out, &data);
if (ret)
return ret;
}
out[cnt] ^= *pos;
pos++;
cnt++;
len--;
}
}
/* 10.4.3 step 4.2 for last block */
if (cnt)
ret = drbg_kcapi_sym(drbg, out, &data);
return ret;
}
/*
* scratchpad usage: drbg_ctr_update is interlinked with drbg_ctr_df
* (and drbg_ctr_bcc, but this function does not need any temporary buffers),
* the scratchpad is used as follows:
* drbg_ctr_update:
* temp
* start: drbg->scratchpad
* length: drbg_statelen(drbg) + drbg_blocklen(drbg)
* note: the cipher writing into this variable works
* blocklen-wise. Now, when the statelen is not a multiple
* of blocklen, the generateion loop below "spills over"
* by at most blocklen. Thus, we need to give sufficient
* memory.
* df_data
* start: drbg->scratchpad +
* drbg_statelen(drbg) + drbg_blocklen(drbg)
* length: drbg_statelen(drbg)
*
* drbg_ctr_df:
* pad
* start: df_data + drbg_statelen(drbg)
* length: drbg_blocklen(drbg)
* iv
* start: pad + drbg_blocklen(drbg)
* length: drbg_blocklen(drbg)
* temp
* start: iv + drbg_blocklen(drbg)
* length: drbg_satelen(drbg) + drbg_blocklen(drbg)
* note: temp is the buffer that the BCC function operates
* on. BCC operates blockwise. drbg_statelen(drbg)
* is sufficient when the DRBG state length is a multiple
* of the block size. For AES192 (and maybe other ciphers)
* this is not correct and the length for temp is
* insufficient (yes, that also means for such ciphers,
* the final output of all BCC rounds are truncated).
* Therefore, add drbg_blocklen(drbg) to cover all
* possibilities.
*/
/* Derivation Function for CTR DRBG as defined in 10.4.2 */
static int drbg_ctr_df(struct drbg_state *drbg,
unsigned char *df_data, size_t bytes_to_return,
struct list_head *seedlist)
{
int ret = -EFAULT;
unsigned char L_N[8];
/* S3 is input */
struct drbg_string S1, S2, S4, cipherin;
LIST_HEAD(bcc_list);
unsigned char *pad = df_data + drbg_statelen(drbg);
unsigned char *iv = pad + drbg_blocklen(drbg);
unsigned char *temp = iv + drbg_blocklen(drbg);
size_t padlen = 0;
unsigned int templen = 0;
/* 10.4.2 step 7 */
unsigned int i = 0;
/* 10.4.2 step 8 */
const unsigned char *K = (unsigned char *)
"\x00\x01\x02\x03\x04\x05\x06\x07"
"\x08\x09\x0a\x0b\x0c\x0d\x0e\x0f"
"\x10\x11\x12\x13\x14\x15\x16\x17"
"\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f";
unsigned char *X;
size_t generated_len = 0;
size_t inputlen = 0;
struct drbg_string *seed = NULL;
memset(pad, 0, drbg_blocklen(drbg));
memset(iv, 0, drbg_blocklen(drbg));
/* 10.4.2 step 1 is implicit as we work byte-wise */
/* 10.4.2 step 2 */
if ((512/8) < bytes_to_return)
return -EINVAL;
/* 10.4.2 step 2 -- calculate the entire length of all input data */
list_for_each_entry(seed, seedlist, list)
inputlen += seed->len;
drbg_cpu_to_be32(inputlen, &L_N[0]);
/* 10.4.2 step 3 */
drbg_cpu_to_be32(bytes_to_return, &L_N[4]);
/* 10.4.2 step 5: length is L_N, input_string, one byte, padding */
padlen = (inputlen + sizeof(L_N) + 1) % (drbg_blocklen(drbg));
/* wrap the padlen appropriately */
if (padlen)
padlen = drbg_blocklen(drbg) - padlen;
/*
* pad / padlen contains the 0x80 byte and the following zero bytes.
* As the calculated padlen value only covers the number of zero
* bytes, this value has to be incremented by one for the 0x80 byte.
*/
padlen++;
pad[0] = 0x80;
/* 10.4.2 step 4 -- first fill the linked list and then order it */
drbg_string_fill(&S1, iv, drbg_blocklen(drbg));
list_add_tail(&S1.list, &bcc_list);
drbg_string_fill(&S2, L_N, sizeof(L_N));
list_add_tail(&S2.list, &bcc_list);
list_splice_tail(seedlist, &bcc_list);
drbg_string_fill(&S4, pad, padlen);
list_add_tail(&S4.list, &bcc_list);
/* 10.4.2 step 9 */
while (templen < (drbg_keylen(drbg) + (drbg_blocklen(drbg)))) {
/*
* 10.4.2 step 9.1 - the padding is implicit as the buffer
* holds zeros after allocation -- even the increment of i
* is irrelevant as the increment remains within length of i
*/
drbg_cpu_to_be32(i, iv);
/* 10.4.2 step 9.2 -- BCC and concatenation with temp */
ret = drbg_ctr_bcc(drbg, temp + templen, K, &bcc_list);
if (ret)
goto out;
/* 10.4.2 step 9.3 */
i++;
templen += drbg_blocklen(drbg);
}
/* 10.4.2 step 11 */
X = temp + (drbg_keylen(drbg));
drbg_string_fill(&cipherin, X, drbg_blocklen(drbg));
/* 10.4.2 step 12: overwriting of outval is implemented in next step */
/* 10.4.2 step 13 */
drbg_kcapi_symsetkey(drbg, temp);
while (generated_len < bytes_to_return) {
short blocklen = 0;
/*
* 10.4.2 step 13.1: the truncation of the key length is
* implicit as the key is only drbg_blocklen in size based on
* the implementation of the cipher function callback
*/
ret = drbg_kcapi_sym(drbg, X, &cipherin);
if (ret)
goto out;
blocklen = (drbg_blocklen(drbg) <
(bytes_to_return - generated_len)) ?
drbg_blocklen(drbg) :
(bytes_to_return - generated_len);
/* 10.4.2 step 13.2 and 14 */
memcpy(df_data + generated_len, X, blocklen);
generated_len += blocklen;
}
ret = 0;
out:
memset(iv, 0, drbg_blocklen(drbg));
memset(temp, 0, drbg_statelen(drbg) + drbg_blocklen(drbg));
memset(pad, 0, drbg_blocklen(drbg));
return ret;
}
/*
* update function of CTR DRBG as defined in 10.2.1.2
*
* The reseed variable has an enhanced meaning compared to the update
* functions of the other DRBGs as follows:
* 0 => initial seed from initialization
* 1 => reseed via drbg_seed
* 2 => first invocation from drbg_ctr_update when addtl is present. In
* this case, the df_data scratchpad is not deleted so that it is
* available for another calls to prevent calling the DF function
* again.
* 3 => second invocation from drbg_ctr_update. When the update function
* was called with addtl, the df_data memory already contains the
* DFed addtl information and we do not need to call DF again.
*/
static int drbg_ctr_update(struct drbg_state *drbg, struct list_head *seed,
int reseed)
{
int ret = -EFAULT;
/* 10.2.1.2 step 1 */
unsigned char *temp = drbg->scratchpad;
unsigned char *df_data = drbg->scratchpad + drbg_statelen(drbg) +
drbg_blocklen(drbg);
if (3 > reseed)
memset(df_data, 0, drbg_statelen(drbg));
if (!reseed) {
/*
* The DRBG uses the CTR mode of the underlying AES cipher. The
* CTR mode increments the counter value after the AES operation
* but SP800-90A requires that the counter is incremented before
* the AES operation. Hence, we increment it at the time we set
* it by one.
*/
crypto_inc(drbg->V, drbg_blocklen(drbg));
ret = crypto_skcipher_setkey(drbg->ctr_handle, drbg->C,
drbg_keylen(drbg));
if (ret)
goto out;
}
/* 10.2.1.3.2 step 2 and 10.2.1.4.2 step 2 */
if (seed) {
ret = drbg_ctr_df(drbg, df_data, drbg_statelen(drbg), seed);
if (ret)
goto out;
}
ret = drbg_kcapi_sym_ctr(drbg, df_data, drbg_statelen(drbg),
temp, drbg_statelen(drbg));
if (ret)
return ret;
/* 10.2.1.2 step 5 */
ret = crypto_skcipher_setkey(drbg->ctr_handle, temp,
drbg_keylen(drbg));
if (ret)
goto out;
/* 10.2.1.2 step 6 */
memcpy(drbg->V, temp + drbg_keylen(drbg), drbg_blocklen(drbg));
/* See above: increment counter by one to compensate timing of CTR op */
crypto_inc(drbg->V, drbg_blocklen(drbg));
ret = 0;
out:
memset(temp, 0, drbg_statelen(drbg) + drbg_blocklen(drbg));
if (2 != reseed)
memset(df_data, 0, drbg_statelen(drbg));
return ret;
}
/*
* scratchpad use: drbg_ctr_update is called independently from
* drbg_ctr_extract_bytes. Therefore, the scratchpad is reused
*/
/* Generate function of CTR DRBG as defined in 10.2.1.5.2 */
static int drbg_ctr_generate(struct drbg_state *drbg,
unsigned char *buf, unsigned int buflen,
struct list_head *addtl)
{
int ret;
int len = min_t(int, buflen, INT_MAX);
/* 10.2.1.5.2 step 2 */
if (addtl && !list_empty(addtl)) {
ret = drbg_ctr_update(drbg, addtl, 2);
if (ret)
return 0;
}
/* 10.2.1.5.2 step 4.1 */
ret = drbg_kcapi_sym_ctr(drbg, drbg->ctr_null_value, DRBG_CTR_NULL_LEN,
buf, len);
if (ret)
return ret;
/* 10.2.1.5.2 step 6 */
ret = drbg_ctr_update(drbg, NULL, 3);
if (ret)
len = ret;
return len;
}
static const struct drbg_state_ops drbg_ctr_ops = {
.update = drbg_ctr_update,
.generate = drbg_ctr_generate,
.crypto_init = drbg_init_sym_kernel,
.crypto_fini = drbg_fini_sym_kernel,
};
#endif /* CONFIG_CRYPTO_DRBG_CTR */
/******************************************************************
* HMAC DRBG callback functions
******************************************************************/
#if defined(CONFIG_CRYPTO_DRBG_HASH) || defined(CONFIG_CRYPTO_DRBG_HMAC)
static int drbg_kcapi_hash(struct drbg_state *drbg, unsigned char *outval,
const struct list_head *in);
static void drbg_kcapi_hmacsetkey(struct drbg_state *drbg,
const unsigned char *key);
static int drbg_init_hash_kernel(struct drbg_state *drbg);
static int drbg_fini_hash_kernel(struct drbg_state *drbg);
#endif /* (CONFIG_CRYPTO_DRBG_HASH || CONFIG_CRYPTO_DRBG_HMAC) */
#ifdef CONFIG_CRYPTO_DRBG_HMAC
#define CRYPTO_DRBG_HMAC_STRING "HMAC "
MODULE_ALIAS_CRYPTO("drbg_pr_hmac_sha512");
MODULE_ALIAS_CRYPTO("drbg_nopr_hmac_sha512");
MODULE_ALIAS_CRYPTO("drbg_pr_hmac_sha384");
MODULE_ALIAS_CRYPTO("drbg_nopr_hmac_sha384");
MODULE_ALIAS_CRYPTO("drbg_pr_hmac_sha256");
MODULE_ALIAS_CRYPTO("drbg_nopr_hmac_sha256");
MODULE_ALIAS_CRYPTO("drbg_pr_hmac_sha1");
MODULE_ALIAS_CRYPTO("drbg_nopr_hmac_sha1");
/* update function of HMAC DRBG as defined in 10.1.2.2 */
static int drbg_hmac_update(struct drbg_state *drbg, struct list_head *seed,
int reseed)
{
int ret = -EFAULT;
int i = 0;
struct drbg_string seed1, seed2, vdata;
LIST_HEAD(seedlist);
LIST_HEAD(vdatalist);
if (!reseed) {
/* 10.1.2.3 step 2 -- memset(0) of C is implicit with kzalloc */
memset(drbg->V, 1, drbg_statelen(drbg));
drbg_kcapi_hmacsetkey(drbg, drbg->C);
}
drbg_string_fill(&seed1, drbg->V, drbg_statelen(drbg));
list_add_tail(&seed1.list, &seedlist);
/* buffer of seed2 will be filled in for loop below with one byte */
drbg_string_fill(&seed2, NULL, 1);
list_add_tail(&seed2.list, &seedlist);
/* input data of seed is allowed to be NULL at this point */
if (seed)
list_splice_tail(seed, &seedlist);
drbg_string_fill(&vdata, drbg->V, drbg_statelen(drbg));
list_add_tail(&vdata.list, &vdatalist);
for (i = 2; 0 < i; i--) {
/* first round uses 0x0, second 0x1 */
unsigned char prefix = DRBG_PREFIX0;
if (1 == i)
prefix = DRBG_PREFIX1;
/* 10.1.2.2 step 1 and 4 -- concatenation and HMAC for key */
seed2.buf = &prefix;
ret = drbg_kcapi_hash(drbg, drbg->C, &seedlist);
if (ret)
return ret;
drbg_kcapi_hmacsetkey(drbg, drbg->C);
/* 10.1.2.2 step 2 and 5 -- HMAC for V */
ret = drbg_kcapi_hash(drbg, drbg->V, &vdatalist);
if (ret)
return ret;
/* 10.1.2.2 step 3 */
if (!seed)
return ret;
}
return 0;
}
/* generate function of HMAC DRBG as defined in 10.1.2.5 */
static int drbg_hmac_generate(struct drbg_state *drbg,
unsigned char *buf,
unsigned int buflen,
struct list_head *addtl)
{
int len = 0;
int ret = 0;
struct drbg_string data;
LIST_HEAD(datalist);
/* 10.1.2.5 step 2 */
if (addtl && !list_empty(addtl)) {
ret = drbg_hmac_update(drbg, addtl, 1);
if (ret)
return ret;
}
drbg_string_fill(&data, drbg->V, drbg_statelen(drbg));
list_add_tail(&data.list, &datalist);
while (len < buflen) {
unsigned int outlen = 0;
/* 10.1.2.5 step 4.1 */
ret = drbg_kcapi_hash(drbg, drbg->V, &datalist);
if (ret)
return ret;
outlen = (drbg_blocklen(drbg) < (buflen - len)) ?
drbg_blocklen(drbg) : (buflen - len);
/* 10.1.2.5 step 4.2 */
memcpy(buf + len, drbg->V, outlen);
len += outlen;
}
/* 10.1.2.5 step 6 */
if (addtl && !list_empty(addtl))
ret = drbg_hmac_update(drbg, addtl, 1);
else
ret = drbg_hmac_update(drbg, NULL, 1);
if (ret)
return ret;
return len;
}
static const struct drbg_state_ops drbg_hmac_ops = {
.update = drbg_hmac_update,
.generate = drbg_hmac_generate,
.crypto_init = drbg_init_hash_kernel,
.crypto_fini = drbg_fini_hash_kernel,
};
#endif /* CONFIG_CRYPTO_DRBG_HMAC */
/******************************************************************
* Hash DRBG callback functions
******************************************************************/
#ifdef CONFIG_CRYPTO_DRBG_HASH
#define CRYPTO_DRBG_HASH_STRING "HASH "
MODULE_ALIAS_CRYPTO("drbg_pr_sha512");
MODULE_ALIAS_CRYPTO("drbg_nopr_sha512");
MODULE_ALIAS_CRYPTO("drbg_pr_sha384");
MODULE_ALIAS_CRYPTO("drbg_nopr_sha384");
MODULE_ALIAS_CRYPTO("drbg_pr_sha256");
MODULE_ALIAS_CRYPTO("drbg_nopr_sha256");
MODULE_ALIAS_CRYPTO("drbg_pr_sha1");
MODULE_ALIAS_CRYPTO("drbg_nopr_sha1");
/*
* Increment buffer
*
* @dst buffer to increment
* @add value to add
*/
static inline void drbg_add_buf(unsigned char *dst, size_t dstlen,
const unsigned char *add, size_t addlen)
{
/* implied: dstlen > addlen */
unsigned char *dstptr;
const unsigned char *addptr;
unsigned int remainder = 0;
size_t len = addlen;
dstptr = dst + (dstlen-1);
addptr = add + (addlen-1);
while (len) {
remainder += *dstptr + *addptr;
*dstptr = remainder & 0xff;
remainder >>= 8;
len--; dstptr--; addptr--;
}
len = dstlen - addlen;
while (len && remainder > 0) {
remainder = *dstptr + 1;
*dstptr = remainder & 0xff;
remainder >>= 8;
len--; dstptr--;
}
}
/*
* scratchpad usage: as drbg_hash_update and drbg_hash_df are used
* interlinked, the scratchpad is used as follows:
* drbg_hash_update
* start: drbg->scratchpad
* length: drbg_statelen(drbg)
* drbg_hash_df:
* start: drbg->scratchpad + drbg_statelen(drbg)
* length: drbg_blocklen(drbg)
*
* drbg_hash_process_addtl uses the scratchpad, but fully completes
* before either of the functions mentioned before are invoked. Therefore,
* drbg_hash_process_addtl does not need to be specifically considered.
*/
/* Derivation Function for Hash DRBG as defined in 10.4.1 */
static int drbg_hash_df(struct drbg_state *drbg,
unsigned char *outval, size_t outlen,
struct list_head *entropylist)
{
int ret = 0;
size_t len = 0;
unsigned char input[5];
unsigned char *tmp = drbg->scratchpad + drbg_statelen(drbg);
struct drbg_string data;
/* 10.4.1 step 3 */
input[0] = 1;
drbg_cpu_to_be32((outlen * 8), &input[1]);
/* 10.4.1 step 4.1 -- concatenation of data for input into hash */
drbg_string_fill(&data, input, 5);
list_add(&data.list, entropylist);
/* 10.4.1 step 4 */
while (len < outlen) {
short blocklen = 0;
/* 10.4.1 step 4.1 */
ret = drbg_kcapi_hash(drbg, tmp, entropylist);
if (ret)
goto out;
/* 10.4.1 step 4.2 */
input[0]++;
blocklen = (drbg_blocklen(drbg) < (outlen - len)) ?
drbg_blocklen(drbg) : (outlen - len);
memcpy(outval + len, tmp, blocklen);
len += blocklen;
}
out:
memset(tmp, 0, drbg_blocklen(drbg));
return ret;
}
/* update function for Hash DRBG as defined in 10.1.1.2 / 10.1.1.3 */
static int drbg_hash_update(struct drbg_state *drbg, struct list_head *seed,
int reseed)
{
int ret = 0;
struct drbg_string data1, data2;
LIST_HEAD(datalist);
LIST_HEAD(datalist2);
unsigned char *V = drbg->scratchpad;
unsigned char prefix = DRBG_PREFIX1;
if (!seed)
return -EINVAL;
if (reseed) {
/* 10.1.1.3 step 1 */
memcpy(V, drbg->V, drbg_statelen(drbg));
drbg_string_fill(&data1, &prefix, 1);
list_add_tail(&data1.list, &datalist);
drbg_string_fill(&data2, V, drbg_statelen(drbg));
list_add_tail(&data2.list, &datalist);
}
list_splice_tail(seed, &datalist);
/* 10.1.1.2 / 10.1.1.3 step 2 and 3 */
ret = drbg_hash_df(drbg, drbg->V, drbg_statelen(drbg), &datalist);
if (ret)
goto out;
/* 10.1.1.2 / 10.1.1.3 step 4 */
prefix = DRBG_PREFIX0;
drbg_string_fill(&data1, &prefix, 1);
list_add_tail(&data1.list, &datalist2);
drbg_string_fill(&data2, drbg->V, drbg_statelen(drbg));
list_add_tail(&data2.list, &datalist2);
/* 10.1.1.2 / 10.1.1.3 step 4 */
ret = drbg_hash_df(drbg, drbg->C, drbg_statelen(drbg), &datalist2);
out:
memset(drbg->scratchpad, 0, drbg_statelen(drbg));
return ret;
}
/* processing of additional information string for Hash DRBG */
static int drbg_hash_process_addtl(struct drbg_state *drbg,
struct list_head *addtl)
{
int ret = 0;
struct drbg_string data1, data2;
LIST_HEAD(datalist);
unsigned char prefix = DRBG_PREFIX2;
/* 10.1.1.4 step 2 */
if (!addtl || list_empty(addtl))
return 0;
/* 10.1.1.4 step 2a */
drbg_string_fill(&data1, &prefix, 1);
drbg_string_fill(&data2, drbg->V, drbg_statelen(drbg));
list_add_tail(&data1.list, &datalist);
list_add_tail(&data2.list, &datalist);
list_splice_tail(addtl, &datalist);
ret = drbg_kcapi_hash(drbg, drbg->scratchpad, &datalist);
if (ret)
goto out;
/* 10.1.1.4 step 2b */
drbg_add_buf(drbg->V, drbg_statelen(drbg),
drbg->scratchpad, drbg_blocklen(drbg));
out:
memset(drbg->scratchpad, 0, drbg_blocklen(drbg));
return ret;
}
/* Hashgen defined in 10.1.1.4 */
static int drbg_hash_hashgen(struct drbg_state *drbg,
unsigned char *buf,
unsigned int buflen)
{
int len = 0;
int ret = 0;
unsigned char *src = drbg->scratchpad;
unsigned char *dst = drbg->scratchpad + drbg_statelen(drbg);
struct drbg_string data;
LIST_HEAD(datalist);
/* 10.1.1.4 step hashgen 2 */
memcpy(src, drbg->V, drbg_statelen(drbg));
drbg_string_fill(&data, src, drbg_statelen(drbg));
list_add_tail(&data.list, &datalist);
while (len < buflen) {
unsigned int outlen = 0;
/* 10.1.1.4 step hashgen 4.1 */
ret = drbg_kcapi_hash(drbg, dst, &datalist);
if (ret) {
len = ret;
goto out;
}
outlen = (drbg_blocklen(drbg) < (buflen - len)) ?
drbg_blocklen(drbg) : (buflen - len);
/* 10.1.1.4 step hashgen 4.2 */
memcpy(buf + len, dst, outlen);
len += outlen;
/* 10.1.1.4 hashgen step 4.3 */
if (len < buflen)
crypto_inc(src, drbg_statelen(drbg));
}
out:
memset(drbg->scratchpad, 0,
(drbg_statelen(drbg) + drbg_blocklen(drbg)));
return len;
}
/* generate function for Hash DRBG as defined in 10.1.1.4 */
static int drbg_hash_generate(struct drbg_state *drbg,
unsigned char *buf, unsigned int buflen,
struct list_head *addtl)
{
int len = 0;
int ret = 0;
union {
unsigned char req[8];
__be64 req_int;
} u;
unsigned char prefix = DRBG_PREFIX3;
struct drbg_string data1, data2;
LIST_HEAD(datalist);
/* 10.1.1.4 step 2 */
ret = drbg_hash_process_addtl(drbg, addtl);
if (ret)
return ret;
/* 10.1.1.4 step 3 */
len = drbg_hash_hashgen(drbg, buf, buflen);
/* this is the value H as documented in 10.1.1.4 */
/* 10.1.1.4 step 4 */
drbg_string_fill(&data1, &prefix, 1);
list_add_tail(&data1.list, &datalist);
drbg_string_fill(&data2, drbg->V, drbg_statelen(drbg));
list_add_tail(&data2.list, &datalist);
ret = drbg_kcapi_hash(drbg, drbg->scratchpad, &datalist);
if (ret) {
len = ret;
goto out;
}
/* 10.1.1.4 step 5 */
drbg_add_buf(drbg->V, drbg_statelen(drbg),
drbg->scratchpad, drbg_blocklen(drbg));
drbg_add_buf(drbg->V, drbg_statelen(drbg),
drbg->C, drbg_statelen(drbg));
u.req_int = cpu_to_be64(drbg->reseed_ctr);
drbg_add_buf(drbg->V, drbg_statelen(drbg), u.req, 8);
out:
memset(drbg->scratchpad, 0, drbg_blocklen(drbg));
return len;
}
/*
* scratchpad usage: as update and generate are used isolated, both
* can use the scratchpad
*/
static const struct drbg_state_ops drbg_hash_ops = {
.update = drbg_hash_update,
.generate = drbg_hash_generate,
.crypto_init = drbg_init_hash_kernel,
.crypto_fini = drbg_fini_hash_kernel,
};
#endif /* CONFIG_CRYPTO_DRBG_HASH */
/******************************************************************
* Functions common for DRBG implementations
******************************************************************/
static inline int __drbg_seed(struct drbg_state *drbg, struct list_head *seed,
int reseed)
{
int ret = drbg->d_ops->update(drbg, seed, reseed);
if (ret)
return ret;
drbg->seeded = true;
/* 10.1.1.2 / 10.1.1.3 step 5 */
drbg->reseed_ctr = 1;
return ret;