Training courses

Kernel and Embedded Linux

Bootlin training courses

Embedded Linux, kernel,
Yocto Project, Buildroot, real-time,
graphics, boot time, debugging...

Bootlin logo

Elixir Cross Referencer

   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
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063
2064
2065
2066
2067
2068
2069
2070
2071
2072
2073
2074
2075
2076
2077
2078
2079
2080
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
2101
2102
2103
2104
2105
2106
2107
2108
2109
2110
2111
2112
2113
2114
2115
2116
2117
2118
2119
2120
2121
2122
2123
2124
2125
2126
2127
2128
2129
2130
2131
2132
2133
2134
2135
2136
2137
2138
2139
2140
2141
2142
2143
2144
2145
2146
2147
/*
 * 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;
	}
}

/*
 * FIPS 140-2 continuous self test for the noise source
 * The test is performed on the noise source input data. Thus, the function
 * implicitly knows the size of the buffer to be equal to the security
 * strength.
 *
 * Note, this function disregards the nonce trailing the entropy data during
 * initial seeding.
 *
 * drbg->drbg_mutex must have been taken.
 *
 * @drbg DRBG handle
 * @entropy buffer of seed data to be checked
 *
 * return:
 *	0 on success
 *	-EAGAIN on when the CTRNG is not yet primed
 *	< 0 on error
 */
static int drbg_fips_continuous_test(struct drbg_state *drbg,
				     const unsigned char *entropy)
{
	unsigned short entropylen = drbg_sec_strength(drbg->core->flags);
	int ret = 0;

	if (!IS_ENABLED(CONFIG_CRYPTO_FIPS))
		return 0;

	/* skip test if we test the overall system */
	if (list_empty(&drbg->test_data.list))
		return 0;
	/* only perform test in FIPS mode */
	if (!fips_enabled)
		return 0;

	if (!drbg->fips_primed) {
		/* Priming of FIPS test */
		memcpy(drbg->prev, entropy, entropylen);
		drbg->fips_primed = true;
		/* priming: another round is needed */
		return -EAGAIN;
	}
	ret = memcmp(drbg->prev, entropy, entropylen);
	if (!ret)
		panic("DRBG continuous self test failed\n");
	memcpy(drbg->prev, entropy, entropylen);

	/* the test shall pass when the two values are not equal */
	return 0;
}

/*
 * 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_OUTSCRATCHLEN 256

/* 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, NULL, 0, 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;
}

static inline int drbg_get_random_bytes(struct drbg_state *drbg,
					unsigned char *entropy,
					unsigned int entropylen)
{
	int ret;

	do {
		get_random_bytes(entropy, entropylen);
		ret = drbg_fips_continuous_test(drbg, entropy);
		if (ret && ret != -EAGAIN)
			return ret;
	} while (ret);

	return 0;
}

static void drbg_async_seed(struct work_struct *work)
{
	struct drbg_string data;
	LIST_HEAD(seedlist);
	struct drbg_state *drbg = container_of(work, struct drbg_state,
					       seed_work);
	unsigned int entropylen = drbg_sec_strength(drbg->core->flags);
	unsigned char entropy[32];
	int ret;

	BUG_ON(!entropylen);
	BUG_ON(entropylen > sizeof(entropy));

	drbg_string_fill(&data, entropy, entropylen);
	list_add_tail(&data.list, &seedlist);

	mutex_lock(&drbg->drbg_mutex);

	ret = drbg_get_random_bytes(drbg, entropy, entropylen);
	if (ret)
		goto unlock;

	/* If nonblocking pool is initialized, deactivate Jitter RNG */
	crypto_free_rng(drbg->jent);
	drbg->jent = NULL;

	/* Set seeded to false so that if __drbg_seed fails the
	 * next generate call will trigger a reseed.
	 */
	drbg->seeded = false;

	__drbg_seed(drbg, &seedlist, true);

	if (drbg->seeded)
		drbg->reseed_threshold = drbg_max_requests(drbg);

unlock:
	mutex_unlock(&drbg->drbg_mutex);

	memzero_explicit(entropy, entropylen);
}

/*
 * Seeding or reseeding of the DRBG
 *
 * @drbg: DRBG state struct
 * @pers: personalization / additional information buffer
 * @reseed: 0 for initial seed process, 1 for reseeding
 *
 * return:
 *	0 on success
 *	error value otherwise
 */
static int drbg_seed(struct drbg_state *drbg, struct drbg_string *pers,
		     bool reseed)
{
	int ret;
	unsigned char entropy[((32 + 16) * 2)];
	unsigned int entropylen = drbg_sec_strength(drbg->core->flags);
	struct drbg_string data1;
	LIST_HEAD(seedlist);

	/* 9.1 / 9.2 / 9.3.1 step 3 */
	if (pers && pers->len > (drbg_max_addtl(drbg))) {
		pr_devel("DRBG: personalization string too long %zu\n",
			 pers->len);
		return -EINVAL;
	}

	if (list_empty(&drbg->test_data.list)) {
		drbg_string_fill(&data1, drbg->test_data.buf,
				 drbg->test_data.len);
		pr_devel("DRBG: using test entropy\n");
	} else {
		/*
		 * Gather entropy equal to the security strength of the DRBG.
		 * With a derivation function, a nonce is required in addition
		 * to the entropy. A nonce must be at least 1/2 of the security
		 * strength of the DRBG in size. Thus, entropy + nonce is 3/2
		 * of the strength. The consideration of a nonce is only
		 * applicable during initial seeding.
		 */
		BUG_ON(!entropylen);
		if (!reseed)
			entropylen = ((entropylen + 1) / 2) * 3;
		BUG_ON((entropylen * 2) > sizeof(entropy));

		/* Get seed from in-kernel /dev/urandom */
		ret = drbg_get_random_bytes(drbg, entropy, entropylen);
		if (ret)
			goto out;

		if (!drbg->jent) {
			drbg_string_fill(&data1, entropy, entropylen);
			pr_devel("DRBG: (re)seeding with %u bytes of entropy\n",
				 entropylen);
		} else {
			/* Get seed from Jitter RNG */
			ret = crypto_rng_get_bytes(drbg->jent,
						   entropy + entropylen,
						   entropylen);
			if (ret) {
				pr_devel("DRBG: jent failed with %d\n", ret);
				goto out;
			}

			drbg_string_fill(&data1, entropy, entropylen * 2);
			pr_devel("DRBG: (re)seeding with %u bytes of entropy\n",
				 entropylen * 2);
		}
	}
	list_add_tail(&data1.list, &seedlist);

	/*
	 * concatenation of entropy with personalization str / addtl input)
	 * the variable pers is directly handed in by the caller, so check its
	 * contents whether it is appropriate
	 */
	if (pers && pers->buf && 0 < pers->len) {
		list_add_tail(&pers->list, &seedlist);
		pr_devel("DRBG: using personalization string\n");
	}

	if (!reseed) {
		memset(drbg->V, 0, drbg_statelen(drbg));
		memset(drbg->C, 0, drbg_statelen(drbg));
	}

	ret = __drbg_seed(drbg, &seedlist, reseed);

out:
	memzero_explicit(entropy, entropylen * 2);

	return ret;
}

/* Free all substructures in a DRBG state without the DRBG state structure */
static inline void drbg_dealloc_state(struct drbg_state *drbg)
{
	if (!drbg)
		return;
	kzfree(drbg->Vbuf);
	drbg->Vbuf = NULL;
	drbg->V = NULL;
	kzfree(drbg->Cbuf);
	drbg->Cbuf = NULL;
	drbg->C = NULL;
	kzfree(drbg->scratchpadbuf);
	drbg->scratchpadbuf = NULL;
	drbg->reseed_ctr = 0;
	drbg->d_ops = NULL;
	drbg->core = NULL;
	if (IS_ENABLED(CONFIG_CRYPTO_FIPS)) {
		kzfree(drbg->prev);
		drbg->prev = NULL;
		drbg->fips_primed = false;
	}
}

/*
 * Allocate all sub-structures for a DRBG state.
 * The DRBG state structure must already be allocated.
 */
static inline int drbg_alloc_state(struct drbg_state *drbg)
{
	int ret = -ENOMEM;
	unsigned int sb_size = 0;

	switch (drbg->core->flags & DRBG_TYPE_MASK) {
#ifdef CONFIG_CRYPTO_DRBG_HMAC
	case DRBG_HMAC:
		drbg->d_ops = &drbg_hmac_ops;
		break;
#endif /* CONFIG_CRYPTO_DRBG_HMAC */
#ifdef CONFIG_CRYPTO_DRBG_HASH
	case DRBG_HASH:
		drbg->d_ops = &drbg_hash_ops;
		break;
#endif /* CONFIG_CRYPTO_DRBG_HASH */
#ifdef CONFIG_CRYPTO_DRBG_CTR
	case DRBG_CTR:
		drbg->d_ops = &drbg_ctr_ops;
		break;
#endif /* CONFIG_CRYPTO_DRBG_CTR */
	default:
		ret = -EOPNOTSUPP;
		goto err;
	}

	ret = drbg->d_ops->crypto_init(drbg);
	if (ret < 0)
		goto err;

	drbg->Vbuf = kmalloc(drbg_statelen(drbg) + ret, GFP_KERNEL);
	if (!drbg->Vbuf) {
		ret = -ENOMEM;
		goto fini;
	}
	drbg->V = PTR_ALIGN(drbg->Vbuf, ret + 1);
	drbg->Cbuf = kmalloc(drbg_statelen(drbg) + ret, GFP_KERNEL);
	if (!drbg->Cbuf) {
		ret = -ENOMEM;
		goto fini;
	}
	drbg->C = PTR_ALIGN(drbg->Cbuf, ret + 1);
	/* scratchpad is only generated for CTR and Hash */
	if (drbg->core->flags & DRBG_HMAC)
		sb_size = 0;
	else if (drbg->core->flags & DRBG_CTR)
		sb_size = drbg_statelen(drbg) + drbg_blocklen(drbg) + /* temp */
			  drbg_statelen(drbg) +	/* df_data */
			  drbg_blocklen(drbg) +	/* pad */
			  drbg_blocklen(drbg) +	/* iv */
			  drbg_statelen(drbg) + drbg_blocklen(drbg); /* temp */
	else
		sb_size = drbg_statelen(drbg) + drbg_blocklen(drbg);

	if (0 < sb_size) {
		drbg->scratchpadbuf = kzalloc(sb_size + ret, GFP_KERNEL);
		if (!drbg->scratchpadbuf) {
			ret = -ENOMEM;
			goto fini;
		}
		drbg->scratchpad = PTR_ALIGN(drbg->scratchpadbuf, ret + 1);
	}

	if (IS_ENABLED(CONFIG_CRYPTO_FIPS)) {
		drbg->prev = kzalloc(drbg_sec_strength(drbg->core->flags),
				     GFP_KERNEL);
		if (!drbg->prev)
			goto fini;
		drbg->fips_primed = false;
	}

	return 0;

fini:
	drbg->d_ops->crypto_fini(drbg);
err:
	drbg_dealloc_state(drbg);
	return ret;
}

/*************************************************************************
 * DRBG interface functions
 *************************************************************************/

/*
 * DRBG generate function as required by SP800-90A - this function
 * generates random numbers
 *
 * @drbg DRBG state handle
 * @buf Buffer where to store the random numbers -- the buffer must already
 *      be pre-allocated by caller
 * @buflen Length of output buffer - this value defines the number of random
 *	   bytes pulled from DRBG
 * @addtl Additional input that is mixed into state, may be NULL -- note
 *	  the entropy is pulled by the DRBG internally unconditionally
 *	  as defined in SP800-90A. The additional input is mixed into
 *	  the state in addition to the pulled entropy.
 *
 * return: 0 when all bytes are generated; < 0 in case of an error
 */
static int drbg_generate(struct drbg_state *drbg,
			 unsigned char *buf, unsigned int buflen,
			 struct drbg_string *addtl)
{
	int len = 0;
	LIST_HEAD(addtllist);

	if (!drbg->core) {
		pr_devel("DRBG: not yet seeded\n");
		return -EINVAL;
	}
	if (0 == buflen || !buf) {
		pr_devel("DRBG: no output buffer provided\n");
		return -EINVAL;
	}
	if (addtl && NULL == addtl->buf && 0 < addtl->len) {
		pr_devel("DRBG: wrong format of additional information\n");
		return -EINVAL;
	}

	/* 9.3.1 step 2 */
	len = -EINVAL;
	if (buflen > (drbg_max_request_bytes(drbg))) {
		pr_devel("DRBG: requested random numbers too large %u\n",
			 buflen);
		goto err;
	}

	/* 9.3.1 step 3 is implicit with the chosen DRBG */

	/* 9.3.1 step 4 */
	if (addtl && addtl->len > (drbg_max_addtl(drbg))) {
		pr_devel("DRBG: additional information string too long %zu\n",
			 addtl->len);
		goto err;
	}
	/* 9.3.1 step 5 is implicit with the chosen DRBG */

	/*
	 * 9.3.1 step 6 and 9 supplemented by 9.3.2 step c is implemented
	 * here. The spec is a bit convoluted here, we make it simpler.
	 */
	if (drbg->reseed_threshold < drbg->reseed_ctr)
		drbg->seeded = false;

	if (drbg->pr || !drbg->seeded) {
		pr_devel("DRBG: reseeding before generation (prediction "
			 "resistance: %s, state %s)\n",
			 drbg->pr ? "true" : "false",
			 drbg->seeded ? "seeded" : "unseeded");
		/* 9.3.1 steps 7.1 through 7.3 */
		len = drbg_seed(drbg, addtl, true);
		if (len)
			goto err;
		/* 9.3.1 step 7.4 */
		addtl = NULL;
	}

	if (addtl && 0 < addtl->len)
		list_add_tail(&addtl->list, &addtllist);
	/* 9.3.1 step 8 and 10 */
	len = drbg->d_ops->generate(drbg, buf, buflen, &addtllist);

	/* 10.1.1.4 step 6, 10.1.2.5 step 7, 10.2.1.5.2 step 7 */
	drbg->reseed_ctr++;
	if (0 >= len)
		goto err;

	/*
	 * Section 11.3.3 requires to re-perform self tests after some
	 * generated random numbers. The chosen value after which self
	 * test is performed is arbitrary, but it should be reasonable.
	 * However, we do not perform the self tests because of the following
	 * reasons: it is mathematically impossible that the initial self tests
	 * were successfully and the following are not. If the initial would
	 * pass and the following would not, the kernel integrity is violated.
	 * In this case, the entire kernel operation is questionable and it
	 * is unlikely that the integrity violation only affects the
	 * correct operation of the DRBG.
	 *
	 * Albeit the following code is commented out, it is provided in
	 * case somebody has a need to implement the test of 11.3.3.
	 */
#if 0
	if (drbg->reseed_ctr && !(drbg->reseed_ctr % 4096)) {
		int err = 0;
		pr_devel("DRBG: start to perform self test\n");
		if (drbg->core->flags & DRBG_HMAC)
			err = alg_test("drbg_pr_hmac_sha256",
				       "drbg_pr_hmac_sha256", 0, 0);
		else if (drbg->core->flags & DRBG_CTR)
			err = alg_test("drbg_pr_ctr_aes128",
				       "drbg_pr_ctr_aes128", 0, 0);
		else
			err = alg_test("drbg_pr_sha256",
				       "drbg_pr_sha256", 0, 0);
		if (err) {
			pr_err("DRBG: periodical self test failed\n");
			/*
			 * uninstantiate implies that from now on, only errors
			 * are returned when reusing this DRBG cipher handle
			 */
			drbg_uninstantiate(drbg);
			return 0;
		} else {
			pr_devel("DRBG: self test successful\n");
		}
	}
#endif

	/*
	 * All operations were successful, return 0 as mandated by
	 * the kernel crypto API interface.
	 */
	len = 0;
err:
	return len;
}

/*
 * Wrapper around drbg_generate which can pull arbitrary long strings
 * from the DRBG without hitting the maximum request limitation.
 *
 * Parameters: see drbg_generate
 * Return codes: see drbg_generate -- if one drbg_generate request fails,
 *		 the entire drbg_generate_long request fails
 */
static int drbg_generate_long(struct drbg_state *drbg,
			      unsigned char *buf, unsigned int buflen,
			      struct drbg_string *addtl)
{
	unsigned int len = 0;
	unsigned int slice = 0;
	do {
		int err = 0;
		unsigned int chunk = 0;
		slice = ((buflen - len) / drbg_max_request_bytes(drbg));
		chunk = slice ? drbg_max_request_bytes(drbg) : (buflen - len);
		mutex_lock(&drbg->drbg_mutex);
		err = drbg_generate(drbg, buf + len, chunk, addtl);
		mutex_unlock(&drbg->drbg_mutex);
		if (0 > err)
			return err;
		len += chunk;
	} while (slice > 0 && (len < buflen));
	return 0;
}

static void drbg_schedule_async_seed(struct random_ready_callback *rdy)
{
	struct drbg_state *drbg = container_of(rdy, struct drbg_state,
					       random_ready);

	schedule_work(&drbg->seed_work);
}

static int drbg_prepare_hrng(struct drbg_state *drbg)
{
	int err;

	/* We do not need an HRNG in test mode. */
	if (list_empty(&drbg->test_data.list))
		return 0;

	INIT_WORK(&drbg->seed_work, drbg_async_seed);

	drbg->random_ready.owner = THIS_MODULE;
	drbg->random_ready.func = drbg_schedule_async_seed;

	err = add_random_ready_callback(&drbg->random_ready);

	switch (err) {
	case 0:
		break;

	case -EALREADY:
		err = 0;
		/* fall through */

	default:
		drbg->random_ready.func = NULL;
		return err;
	}

	drbg->jent = crypto_alloc_rng("jitterentropy_rng", 0, 0);

	/*
	 * Require frequent reseeds until the seed source is fully
	 * initialized.
	 */
	drbg->reseed_threshold = 50;

	return err;
}

/*
 * DRBG instantiation function as required by SP800-90A - this function
 * sets up the DRBG handle, performs the initial seeding and all sanity
 * checks required by SP800-90A
 *
 * @drbg memory of state -- if NULL, new memory is allocated
 * @pers Personalization string that is mixed into state, may be NULL -- note
 *	 the entropy is pulled by the DRBG internally unconditionally
 *	 as defined in SP800-90A. The additional input is mixed into
 *	 the state in addition to the pulled entropy.
 * @coreref reference to core
 * @pr prediction resistance enabled
 *
 * return
 *	0 on success
 *	error value otherwise
 */
static int drbg_instantiate(struct drbg_state *drbg, struct drbg_string *pers,
			    int coreref, bool pr)
{
	int ret;
	bool reseed = true;

	pr_devel("DRBG: Initializing DRBG core %d with prediction resistance "
		 "%s\n", coreref, pr ? "enabled" : "disabled");
	mutex_lock(&drbg->drbg_mutex);

	/* 9.1 step 1 is implicit with the selected DRBG type */

	/*
	 * 9.1 step 2 is implicit as caller can select prediction resistance
	 * and the flag is copied into drbg->flags --
	 * all DRBG types support prediction resistance
	 */

	/* 9.1 step 4 is implicit in  drbg_sec_strength */

	if (!drbg->core) {
		drbg->core = &drbg_cores[coreref];
		drbg->pr = pr;
		drbg->seeded = false;
		drbg->reseed_threshold = drbg_max_requests(drbg);

		ret = drbg_alloc_state(drbg);
		if (ret)
			goto unlock;

		ret = drbg_prepare_hrng(drbg);
		if (ret)
			goto free_everything;

		if (IS_ERR(drbg->jent)) {
			ret = PTR_ERR(drbg->jent);
			drbg->jent = NULL;
			if (fips_enabled || ret != -ENOENT)
				goto free_everything;
			pr_info("DRBG: Continuing without Jitter RNG\n");
		}

		reseed = false;
	}

	ret = drbg_seed(drbg, pers, reseed);

	if (ret && !reseed)
		goto free_everything;

	mutex_unlock(&drbg->drbg_mutex);
	return ret;

unlock:
	mutex_unlock(&drbg->drbg_mutex);
	return ret;

free_everything:
	mutex_unlock(&drbg->drbg_mutex);
	drbg_uninstantiate(drbg);
	return ret;
}

/*
 * DRBG uninstantiate function as required by SP800-90A - this function
 * frees all buffers and the DRBG handle
 *
 * @drbg DRBG state handle
 *
 * return
 *	0 on success
 */
static int drbg_uninstantiate(struct drbg_state *drbg)
{
	if (drbg->random_ready.func) {
		del_random_ready_callback(&drbg->random_ready);
		cancel_work_sync(&drbg->seed_work);
		crypto_free_rng(drbg->jent);
		drbg->jent = NULL;
	}

	if (drbg->d_ops)
		drbg->d_ops->crypto_fini(drbg);
	drbg_dealloc_state(drbg);
	/* no scrubbing of test_data -- this shall survive an uninstantiate */
	return 0;
}

/*
 * Helper function for setting the test data in the DRBG
 *
 * @drbg DRBG state handle
 * @data test data
 * @len test data length
 */
static void drbg_kcapi_set_entropy(struct crypto_rng *tfm,
				   const u8 *data, unsigned int len)
{
	struct drbg_state *drbg = crypto_rng_ctx(tfm);

	mutex_lock(&drbg->drbg_mutex);
	drbg_string_fill(&drbg->test_data, data, len);
	mutex_unlock(&drbg->drbg_mutex);
}

/***************************************************************
 * Kernel crypto API cipher invocations requested by DRBG
 ***************************************************************/

#if defined(CONFIG_CRYPTO_DRBG_HASH) || defined(CONFIG_CRYPTO_DRBG_HMAC)
struct sdesc {
	struct shash_desc shash;
	char ctx[];
};

static int drbg_init_hash_kernel(struct drbg_state *drbg)
{
	struct sdesc *sdesc;
	struct crypto_shash *tfm;

	tfm = crypto_alloc_shash(drbg->core->backend_cra_name, 0, 0);
	if (IS_ERR(tfm)) {
		pr_info("DRBG: could not allocate digest TFM handle: %s\n",
				drbg->core->backend_cra_name);
		return PTR_ERR(tfm);
	}
	BUG_ON(drbg_blocklen(drbg) != crypto_shash_digestsize(tfm));
	sdesc = kzalloc(sizeof(struct shash_desc) + crypto_shash_descsize(tfm),
			GFP_KERNEL);
	if (!sdesc) {
		crypto_free_shash(tfm);
		return -ENOMEM;
	}

	sdesc->shash.tfm = tfm;
	drbg->priv_data = sdesc;

	return crypto_shash_alignmask(tfm);
}

static int drbg_fini_hash_kernel(struct drbg_state *drbg)
{
	struct sdesc *sdesc = (struct sdesc *)drbg->priv_data;
	if (sdesc) {
		crypto_free_shash(sdesc->shash.tfm);
		kzfree(sdesc);
	}
	drbg->priv_data = NULL;
	return 0;
}

static void drbg_kcapi_hmacsetkey(struct drbg_state *drbg,
				  const unsigned char *key)
{
	struct sdesc *sdesc = (struct sdesc *)drbg->priv_data;

	crypto_shash_setkey(sdesc->shash.tfm, key, drbg_statelen(drbg));
}

static int drbg_kcapi_hash(struct drbg_state *drbg, unsigned char *outval,
			   const struct list_head *in)
{
	struct sdesc *sdesc = (struct sdesc *)drbg->priv_data;
	struct drbg_string *input = NULL;

	crypto_shash_init(&sdesc->shash);
	list_for_each_entry(input, in, list)
		crypto_shash_update(&sdesc->shash, input->buf, input->len);
	return crypto_shash_final(&sdesc->shash, outval);
}
#endif /* (CONFIG_CRYPTO_DRBG_HASH || CONFIG_CRYPTO_DRBG_HMAC) */

#ifdef CONFIG_CRYPTO_DRBG_CTR
static int drbg_fini_sym_kernel(struct drbg_state *drbg)
{
	struct crypto_cipher *tfm =
		(struct crypto_cipher *)drbg->priv_data;
	if (tfm)
		crypto_free_cipher(tfm);
	drbg->priv_data = NULL;

	if (drbg->ctr_handle)
		crypto_free_skcipher(drbg->ctr_handle);
	drbg->ctr_handle = NULL;

	if (drbg->ctr_req)
		skcipher_request_free(drbg->ctr_req);
	drbg->ctr_req = NULL;

	kfree(drbg->outscratchpadbuf);
	drbg->outscratchpadbuf = NULL;

	return 0;
}

static int drbg_init_sym_kernel(struct drbg_state *drbg)
{
	struct crypto_cipher *tfm;
	struct crypto_skcipher *sk_tfm;
	struct skcipher_request *req;
	unsigned int alignmask;
	char ctr_name[CRYPTO_MAX_ALG_NAME];

	tfm = crypto_alloc_cipher(drbg->core->backend_cra_name, 0, 0);
	if (IS_ERR(tfm)) {
		pr_info("DRBG: could not allocate cipher TFM handle: %s\n",
				drbg->core->backend_cra_name);
		return PTR_ERR(tfm);
	}
	BUG_ON(drbg_blocklen(drbg) != crypto_cipher_blocksize(tfm));
	drbg->priv_data = tfm;

	if (snprintf(ctr_name, CRYPTO_MAX_ALG_NAME, "ctr(%s)",
	    drbg->core->backend_cra_name) >= CRYPTO_MAX_ALG_NAME) {
		drbg_fini_sym_kernel(drbg);
		return -EINVAL;
	}
	sk_tfm = crypto_alloc_skcipher(ctr_name, 0, 0);
	if (IS_ERR(sk_tfm)) {
		pr_info("DRBG: could not allocate CTR cipher TFM handle: %s\n",
				ctr_name);
		drbg_fini_sym_kernel(drbg);
		return PTR_ERR(sk_tfm);
	}
	drbg->ctr_handle = sk_tfm;
	crypto_init_wait(&drbg->ctr_wait);

	req = skcipher_request_alloc(sk_tfm, GFP_KERNEL);
	if (!req) {
		pr_info("DRBG: could not allocate request queue\n");
		drbg_fini_sym_kernel(drbg);
		return -ENOMEM;
	}
	drbg->ctr_req = req;
	skcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG |
						CRYPTO_TFM_REQ_MAY_SLEEP,
					crypto_req_done, &drbg->ctr_wait);

	alignmask = crypto_skcipher_alignmask(sk_tfm);
	drbg->outscratchpadbuf = kmalloc(DRBG_OUTSCRATCHLEN + alignmask,
					 GFP_KERNEL);
	if (!drbg->outscratchpadbuf) {
		drbg_fini_sym_kernel(drbg);
		return -ENOMEM;
	}
	drbg->outscratchpad = (u8 *)PTR_ALIGN(drbg->outscratchpadbuf,
					      alignmask + 1);

	sg_init_table(&drbg->sg_in, 1);
	sg_init_one(&drbg->sg_out, drbg->outscratchpad, DRBG_OUTSCRATCHLEN);

	return alignmask;
}

static void drbg_kcapi_symsetkey(struct drbg_state *drbg,
				 const unsigned char *key)
{
	struct crypto_cipher *tfm =
		(struct crypto_cipher *)drbg->priv_data;

	crypto_cipher_setkey(tfm, key, (drbg_keylen(drbg)));
}

static int drbg_kcapi_sym(struct drbg_state *drbg, unsigned char *outval,
			  const struct drbg_string *in)
{
	struct crypto_cipher *tfm =
		(struct crypto_cipher *)drbg->priv_data;

	/* there is only component in *in */
	BUG_ON(in->len < drbg_blocklen(drbg));
	crypto_cipher_encrypt_one(tfm, outval, in->buf);
	return 0;
}

static int drbg_kcapi_sym_ctr(struct drbg_state *drbg,
			      u8 *inbuf, u32 inlen,
			      u8 *outbuf, u32 outlen)
{
	struct scatterlist *sg_in = &drbg->sg_in, *sg_out = &drbg->sg_out;
	u32 scratchpad_use = min_t(u32, outlen, DRBG_OUTSCRATCHLEN);
	int ret;

	if (inbuf) {
		/* Use caller-provided input buffer */
		sg_set_buf(sg_in, inbuf, inlen);
	} else {
		/* Use scratchpad for in-place operation */
		inlen = scratchpad_use;
		memset(drbg->outscratchpad, 0, scratchpad_use);
		sg_set_buf(sg_in, drbg->outscratchpad, scratchpad_use);
	}

	while (outlen) {
		u32 cryptlen = min3(inlen, outlen, (u32)DRBG_OUTSCRATCHLEN);

		/* Output buffer may not be valid for SGL, use scratchpad */
		skcipher_request_set_crypt(drbg->ctr_req, sg_in, sg_out,
					   cryptlen, drbg->V);
		ret = crypto_wait_req(crypto_skcipher_encrypt(drbg->ctr_req),
					&drbg->ctr_wait);
		if (ret)
			goto out;

		crypto_init_wait(&drbg->ctr_wait);

		memcpy(outbuf, drbg->outscratchpad, cryptlen);
		memzero_explicit(drbg->outscratchpad, cryptlen);

		outlen -= cryptlen;
		outbuf += cryptlen;
	}
	ret = 0;

out:
	return ret;
}
#endif /* CONFIG_CRYPTO_DRBG_CTR */

/***************************************************************
 * Kernel crypto API interface to register DRBG
 ***************************************************************/

/*
 * Look up the DRBG flags by given kernel crypto API cra_name
 * The code uses the drbg_cores definition to do this
 *
 * @cra_name kernel crypto API cra_name
 * @coreref reference to integer which is filled with the pointer to
 *  the applicable core
 * @pr reference for setting prediction resistance
 *
 * return: flags
 */
static inline void drbg_convert_tfm_core(const char *cra_driver_name,
					 int *coreref, bool *pr)
{
	int i = 0;
	size_t start = 0;
	int len = 0;

	*pr = true;
	/* disassemble the names */
	if (!memcmp(cra_driver_name, "drbg_nopr_", 10)) {
		start = 10;
		*pr = false;
	} else if (!memcmp(cra_driver_name, "drbg_pr_", 8)) {
		start = 8;
	} else {
		return;
	}

	/* remove the first part */
	len = strlen(cra_driver_name) - start;
	for (i = 0; ARRAY_SIZE(drbg_cores) > i; i++) {
		if (!memcmp(cra_driver_name + start, drbg_cores[i].cra_name,
			    len)) {
			*coreref = i;
			return;
		}
	}
}

static int drbg_kcapi_init(struct crypto_tfm *tfm)
{
	struct drbg_state *drbg = crypto_tfm_ctx(tfm);

	mutex_init(&drbg->drbg_mutex);

	return 0;
}

static void drbg_kcapi_cleanup(struct crypto_tfm *tfm)
{
	drbg_uninstantiate(crypto_tfm_ctx(tfm));
}

/*
 * Generate random numbers invoked by the kernel crypto API:
 * The API of the kernel crypto API is extended as follows:
 *
 * src is additional input supplied to the RNG.
 * slen is the length of src.
 * dst is the output buffer where random data is to be stored.
 * dlen is the length of dst.
 */
static int drbg_kcapi_random(struct crypto_rng *tfm,
			     const u8 *src, unsigned int slen,
			     u8 *dst, unsigned int dlen)
{
	struct drbg_state *drbg = crypto_rng_ctx(tfm);
	struct drbg_string *addtl = NULL;
	struct drbg_string string;

	if (slen) {
		/* linked list variable is now local to allow modification */
		drbg_string_fill(&string, src, slen);
		addtl = &string;
	}

	return drbg_generate_long(drbg, dst, dlen, addtl);
}

/*
 * Seed the DRBG invoked by the kernel crypto API
 */
static int drbg_kcapi_seed(struct crypto_rng *tfm,
			   const u8 *seed, unsigned int slen)
{
	struct drbg_state *drbg = crypto_rng_ctx(tfm);
	struct crypto_tfm *tfm_base = crypto_rng_tfm(tfm);
	bool pr = false;
	struct drbg_string string;
	struct drbg_string *seed_string = NULL;
	int coreref = 0;

	drbg_convert_tfm_core(crypto_tfm_alg_driver_name(tfm_base), &coreref,
			      &pr);
	if (0 < slen) {
		drbg_string_fill(&string, seed, slen);
		seed_string = &string;
	}

	return drbg_instantiate(drbg, seed_string, coreref, pr);
}

/***************************************************************
 * Kernel module: code to load the module
 ***************************************************************/

/*
 * Tests as defined in 11.3.2 in addition to the cipher tests: testing
 * of the error handling.
 *
 * Note: testing of failing seed source as defined in 11.3.2 is not applicable
 * as seed source of get_random_bytes does not fail.
 *
 * Note 2: There is no sensible way of testing the reseed counter
 * enforcement, so skip it.
 */
static inline int __init drbg_healthcheck_sanity(void)
{
	int len = 0;
#define OUTBUFLEN 16
	unsigned char buf[OUTBUFLEN];
	struct drbg_state *drbg = NULL;
	int ret = -EFAULT;
	int rc = -EFAULT;
	bool pr = false;
	int coreref = 0;
	struct drbg_string addtl;
	size_t max_addtllen, max_request_bytes;

	/* only perform test in FIPS mode */
	if (!fips_enabled)
		return 0;

#ifdef CONFIG_CRYPTO_DRBG_CTR
	drbg_convert_tfm_core("drbg_nopr_ctr_aes128", &coreref, &pr);
#elif defined CONFIG_CRYPTO_DRBG_HASH
	drbg_convert_tfm_core("drbg_nopr_sha256", &coreref, &pr);
#else
	drbg_convert_tfm_core("drbg_nopr_hmac_sha256", &coreref, &pr);
#endif

	drbg = kzalloc(sizeof(struct drbg_state), GFP_KERNEL);
	if (!drbg)
		return -ENOMEM;

	mutex_init(&drbg->drbg_mutex);
	drbg->core = &drbg_cores[coreref];
	drbg->reseed_threshold = drbg_max_requests(drbg);

	/*
	 * if the following tests fail, it is likely that there is a buffer
	 * overflow as buf is much smaller than the requested or provided
	 * string lengths -- in case the error handling does not succeed
	 * we may get an OOPS. And we want to get an OOPS as this is a
	 * grave bug.
	 */

	max_addtllen = drbg_max_addtl(drbg);
	max_request_bytes = drbg_max_request_bytes(drbg);
	drbg_string_fill(&addtl, buf, max_addtllen + 1);
	/* overflow addtllen with additonal info string */
	len = drbg_generate(drbg, buf, OUTBUFLEN, &addtl);
	BUG_ON(0 < len);
	/* overflow max_bits */
	len = drbg_generate(drbg, buf, (max_request_bytes + 1), NULL);
	BUG_ON(0 < len);

	/* overflow max addtllen with personalization string */
	ret = drbg_seed(drbg, &addtl, false);
	BUG_ON(0 == ret);
	/* all tests passed */
	rc = 0;

	pr_devel("DRBG: Sanity tests for failure code paths successfully "
		 "completed\n");

	kfree(drbg);
	return rc;
}

static struct rng_alg drbg_algs[22];

/*
 * Fill the array drbg_algs used to register the different DRBGs
 * with the kernel crypto API. To fill the array, the information
 * from drbg_cores[] is used.
 */
static inline void __init drbg_fill_array(struct rng_alg *alg,
					  const struct drbg_core *core, int pr)
{
	int pos = 0;
	static int priority = 200;

	memcpy(alg->base.cra_name, "stdrng", 6);
	if (pr) {
		memcpy(alg->base.cra_driver_name, "drbg_pr_", 8);
		pos = 8;
	} else {
		memcpy(alg->base.cra_driver_name, "drbg_nopr_", 10);
		pos = 10;
	}
	memcpy(alg->base.cra_driver_name + pos, core->cra_name,
	       strlen(core->cra_name));

	alg->base.cra_priority = priority;
	priority++;
	/*
	 * If FIPS mode enabled, the selected DRBG shall have the
	 * highest cra_priority over other stdrng instances to ensure
	 * it is selected.
	 */
	if (fips_enabled)
		alg->base.cra_priority += 200;

	alg->base.cra_ctxsize 	= sizeof(struct drbg_state);
	alg->base.cra_module	= THIS_MODULE;
	alg->base.cra_init	= drbg_kcapi_init;
	alg->base.cra_exit	= drbg_kcapi_cleanup;
	alg->generate		= drbg_kcapi_random;
	alg->seed		= drbg_kcapi_seed;
	alg->set_ent		= drbg_kcapi_set_entropy;
	alg->seedsize		= 0;
}

static int __init drbg_init(void)
{
	unsigned int i = 0; /* pointer to drbg_algs */
	unsigned int j = 0; /* pointer to drbg_cores */
	int ret;

	ret = drbg_healthcheck_sanity();
	if (ret)
		return ret;

	if (ARRAY_SIZE(drbg_cores) * 2 > ARRAY_SIZE(drbg_algs)) {
		pr_info("DRBG: Cannot register all DRBG types"
			"(slots needed: %zu, slots available: %zu)\n",
			ARRAY_SIZE(drbg_cores) * 2, ARRAY_SIZE(drbg_algs));
		return -EFAULT;
	}

	/*
	 * each DRBG definition can be used with PR and without PR, thus
	 * we instantiate each DRBG in drbg_cores[] twice.
	 *
	 * As the order of placing them into the drbg_algs array matters
	 * (the later DRBGs receive a higher cra_priority) we register the
	 * prediction resistance DRBGs first as the should not be too
	 * interesting.
	 */
	for (j = 0; ARRAY_SIZE(drbg_cores) > j; j++, i++)
		drbg_fill_array(&drbg_algs[i], &drbg_cores[j], 1);
	for (j = 0; ARRAY_SIZE(drbg_cores) > j; j++, i++)
		drbg_fill_array(&drbg_algs[i], &drbg_cores[j], 0);
	return crypto_register_rngs(drbg_algs, (ARRAY_SIZE(drbg_cores) * 2));
}

static void __exit drbg_exit(void)
{
	crypto_unregister_rngs(drbg_algs, (ARRAY_SIZE(drbg_cores) * 2));
}

subsys_initcall(drbg_init);
module_exit(drbg_exit);
#ifndef CRYPTO_DRBG_HASH_STRING
#define CRYPTO_DRBG_HASH_STRING ""
#endif
#ifndef CRYPTO_DRBG_HMAC_STRING
#define CRYPTO_DRBG_HMAC_STRING ""
#endif
#ifndef CRYPTO_DRBG_CTR_STRING
#define CRYPTO_DRBG_CTR_STRING ""
#endif
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Stephan Mueller <smueller@chronox.de>");
MODULE_DESCRIPTION("NIST SP800-90A Deterministic Random Bit Generator (DRBG) "
		   "using following cores: "
		   CRYPTO_DRBG_HASH_STRING
		   CRYPTO_DRBG_HMAC_STRING
		   CRYPTO_DRBG_CTR_STRING);
MODULE_ALIAS_CRYPTO("stdrng");