Root/crypto/drbg.c

1/*
2 * DRBG: Deterministic Random Bits Generator
3 * Based on NIST Recommended DRBG from NIST SP800-90A with the following
4 * properties:
5 * * CTR DRBG with DF with AES-128, AES-192, AES-256 cores
6 * * Hash DRBG with DF with SHA-1, SHA-256, SHA-384, SHA-512 cores
7 * * HMAC DRBG with DF with SHA-1, SHA-256, SHA-384, SHA-512 cores
8 * * with and without prediction resistance
9 *
10 * Copyright Stephan Mueller <smueller@chronox.de>, 2014
11 *
12 * Redistribution and use in source and binary forms, with or without
13 * modification, are permitted provided that the following conditions
14 * are met:
15 * 1. Redistributions of source code must retain the above copyright
16 * notice, and the entire permission notice in its entirety,
17 * including the disclaimer of warranties.
18 * 2. Redistributions in binary form must reproduce the above copyright
19 * notice, this list of conditions and the following disclaimer in the
20 * documentation and/or other materials provided with the distribution.
21 * 3. The name of the author may not be used to endorse or promote
22 * products derived from this software without specific prior
23 * written permission.
24 *
25 * ALTERNATIVELY, this product may be distributed under the terms of
26 * the GNU General Public License, in which case the provisions of the GPL are
27 * required INSTEAD OF the above restrictions. (This clause is
28 * necessary due to a potential bad interaction between the GPL and
29 * the restrictions contained in a BSD-style copyright.)
30 *
31 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
32 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
33 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, ALL OF
34 * WHICH ARE HEREBY DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE
35 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
36 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
37 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
38 * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
39 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
40 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
41 * USE OF THIS SOFTWARE, EVEN IF NOT ADVISED OF THE POSSIBILITY OF SUCH
42 * DAMAGE.
43 *
44 * DRBG Usage
45 * ==========
46 * The SP 800-90A DRBG allows the user to specify a personalization string
47 * for initialization as well as an additional information string for each
48 * random number request. The following code fragments show how a caller
49 * uses the kernel crypto API to use the full functionality of the DRBG.
50 *
51 * Usage without any additional data
52 * ---------------------------------
53 * struct crypto_rng *drng;
54 * int err;
55 * char data[DATALEN];
56 *
57 * drng = crypto_alloc_rng(drng_name, 0, 0);
58 * err = crypto_rng_get_bytes(drng, &data, DATALEN);
59 * crypto_free_rng(drng);
60 *
61 *
62 * Usage with personalization string during initialization
63 * -------------------------------------------------------
64 * struct crypto_rng *drng;
65 * int err;
66 * char data[DATALEN];
67 * struct drbg_string pers;
68 * char personalization[11] = "some-string";
69 *
70 * drbg_string_fill(&pers, personalization, strlen(personalization));
71 * drng = crypto_alloc_rng(drng_name, 0, 0);
72 * // The reset completely re-initializes the DRBG with the provided
73 * // personalization string
74 * err = crypto_rng_reset(drng, &personalization, strlen(personalization));
75 * err = crypto_rng_get_bytes(drng, &data, DATALEN);
76 * crypto_free_rng(drng);
77 *
78 *
79 * Usage with additional information string during random number request
80 * ---------------------------------------------------------------------
81 * struct crypto_rng *drng;
82 * int err;
83 * char data[DATALEN];
84 * char addtl_string[11] = "some-string";
85 * string drbg_string addtl;
86 *
87 * drbg_string_fill(&addtl, addtl_string, strlen(addtl_string));
88 * drng = crypto_alloc_rng(drng_name, 0, 0);
89 * // The following call is a wrapper to crypto_rng_get_bytes() and returns
90 * // the same error codes.
91 * err = crypto_drbg_get_bytes_addtl(drng, &data, DATALEN, &addtl);
92 * crypto_free_rng(drng);
93 *
94 *
95 * Usage with personalization and additional information strings
96 * -------------------------------------------------------------
97 * Just mix both scenarios above.
98 */
99
100#include <crypto/drbg.h>
101
102/***************************************************************
103 * Backend cipher definitions available to DRBG
104 ***************************************************************/
105
106/*
107 * The order of the DRBG definitions here matter: every DRBG is registered
108 * as stdrng. Each DRBG receives an increasing cra_priority values the later
109 * they are defined in this array (see drbg_fill_array).
110 *
111 * HMAC DRBGs are favored over Hash DRBGs over CTR DRBGs, and
112 * the SHA256 / AES 256 over other ciphers. Thus, the favored
113 * DRBGs are the latest entries in this array.
114 */
115static const struct drbg_core drbg_cores[] = {
116#ifdef CONFIG_CRYPTO_DRBG_CTR
117    {
118        .flags = DRBG_CTR | DRBG_STRENGTH128,
119        .statelen = 32, /* 256 bits as defined in 10.2.1 */
120        .blocklen_bytes = 16,
121        .cra_name = "ctr_aes128",
122        .backend_cra_name = "ecb(aes)",
123    }, {
124        .flags = DRBG_CTR | DRBG_STRENGTH192,
125        .statelen = 40, /* 320 bits as defined in 10.2.1 */
126        .blocklen_bytes = 16,
127        .cra_name = "ctr_aes192",
128        .backend_cra_name = "ecb(aes)",
129    }, {
130        .flags = DRBG_CTR | DRBG_STRENGTH256,
131        .statelen = 48, /* 384 bits as defined in 10.2.1 */
132        .blocklen_bytes = 16,
133        .cra_name = "ctr_aes256",
134        .backend_cra_name = "ecb(aes)",
135    },
136#endif /* CONFIG_CRYPTO_DRBG_CTR */
137#ifdef CONFIG_CRYPTO_DRBG_HASH
138    {
139        .flags = DRBG_HASH | DRBG_STRENGTH128,
140        .statelen = 55, /* 440 bits */
141        .blocklen_bytes = 20,
142        .cra_name = "sha1",
143        .backend_cra_name = "sha1",
144    }, {
145        .flags = DRBG_HASH | DRBG_STRENGTH256,
146        .statelen = 111, /* 888 bits */
147        .blocklen_bytes = 48,
148        .cra_name = "sha384",
149        .backend_cra_name = "sha384",
150    }, {
151        .flags = DRBG_HASH | DRBG_STRENGTH256,
152        .statelen = 111, /* 888 bits */
153        .blocklen_bytes = 64,
154        .cra_name = "sha512",
155        .backend_cra_name = "sha512",
156    }, {
157        .flags = DRBG_HASH | DRBG_STRENGTH256,
158        .statelen = 55, /* 440 bits */
159        .blocklen_bytes = 32,
160        .cra_name = "sha256",
161        .backend_cra_name = "sha256",
162    },
163#endif /* CONFIG_CRYPTO_DRBG_HASH */
164#ifdef CONFIG_CRYPTO_DRBG_HMAC
165    {
166        .flags = DRBG_HMAC | DRBG_STRENGTH128,
167        .statelen = 20, /* block length of cipher */
168        .blocklen_bytes = 20,
169        .cra_name = "hmac_sha1",
170        .backend_cra_name = "hmac(sha1)",
171    }, {
172        .flags = DRBG_HMAC | DRBG_STRENGTH256,
173        .statelen = 48, /* block length of cipher */
174        .blocklen_bytes = 48,
175        .cra_name = "hmac_sha384",
176        .backend_cra_name = "hmac(sha384)",
177    }, {
178        .flags = DRBG_HMAC | DRBG_STRENGTH256,
179        .statelen = 64, /* block length of cipher */
180        .blocklen_bytes = 64,
181        .cra_name = "hmac_sha512",
182        .backend_cra_name = "hmac(sha512)",
183    }, {
184        .flags = DRBG_HMAC | DRBG_STRENGTH256,
185        .statelen = 32, /* block length of cipher */
186        .blocklen_bytes = 32,
187        .cra_name = "hmac_sha256",
188        .backend_cra_name = "hmac(sha256)",
189    },
190#endif /* CONFIG_CRYPTO_DRBG_HMAC */
191};
192
193/******************************************************************
194 * Generic helper functions
195 ******************************************************************/
196
197/*
198 * Return strength of DRBG according to SP800-90A section 8.4
199 *
200 * @flags DRBG flags reference
201 *
202 * Return: normalized strength in *bytes* value or 32 as default
203 * to counter programming errors
204 */
205static inline unsigned short drbg_sec_strength(drbg_flag_t flags)
206{
207    switch (flags & DRBG_STRENGTH_MASK) {
208    case DRBG_STRENGTH128:
209        return 16;
210    case DRBG_STRENGTH192:
211        return 24;
212    case DRBG_STRENGTH256:
213        return 32;
214    default:
215        return 32;
216    }
217}
218
219/*
220 * FIPS 140-2 continuous self test
221 * The test is performed on the result of one round of the output
222 * function. Thus, the function implicitly knows the size of the
223 * buffer.
224 *
225 * The FIPS test can be called in an endless loop until it returns
226 * true. Although the code looks like a potential for a deadlock, it
227 * is not the case, because returning a false cannot mathematically
228 * occur (except once when a reseed took place and the updated state
229 * would is now set up such that the generation of new value returns
230 * an identical one -- this is most unlikely and would happen only once).
231 * Thus, if this function repeatedly returns false and thus would cause
232 * a deadlock, the integrity of the entire kernel is lost.
233 *
234 * @drbg DRBG handle
235 * @buf output buffer of random data to be checked
236 *
237 * return:
238 * true on success
239 * false on error
240 */
241static bool drbg_fips_continuous_test(struct drbg_state *drbg,
242                      const unsigned char *buf)
243{
244#ifdef CONFIG_CRYPTO_FIPS
245    int ret = 0;
246    /* skip test if we test the overall system */
247    if (drbg->test_data)
248        return true;
249    /* only perform test in FIPS mode */
250    if (0 == fips_enabled)
251        return true;
252    if (!drbg->fips_primed) {
253        /* Priming of FIPS test */
254        memcpy(drbg->prev, buf, drbg_blocklen(drbg));
255        drbg->fips_primed = true;
256        /* return false due to priming, i.e. another round is needed */
257        return false;
258    }
259    ret = memcmp(drbg->prev, buf, drbg_blocklen(drbg));
260    memcpy(drbg->prev, buf, drbg_blocklen(drbg));
261    /* the test shall pass when the two compared values are not equal */
262    return ret != 0;
263#else
264    return true;
265#endif /* CONFIG_CRYPTO_FIPS */
266}
267
268/*
269 * Convert an integer into a byte representation of this integer.
270 * The byte representation is big-endian
271 *
272 * @val value to be converted
273 * @buf buffer holding the converted integer -- caller must ensure that
274 * buffer size is at least 32 bit
275 */
276#if (defined(CONFIG_CRYPTO_DRBG_HASH) || defined(CONFIG_CRYPTO_DRBG_CTR))
277static inline void drbg_cpu_to_be32(__u32 val, unsigned char *buf)
278{
279    struct s {
280        __be32 conv;
281    };
282    struct s *conversion = (struct s *) buf;
283
284    conversion->conv = cpu_to_be32(val);
285}
286
287/*
288 * Increment buffer
289 *
290 * @dst buffer to increment
291 * @add value to add
292 */
293static inline void drbg_add_buf(unsigned char *dst, size_t dstlen,
294                const unsigned char *add, size_t addlen)
295{
296    /* implied: dstlen > addlen */
297    unsigned char *dstptr;
298    const unsigned char *addptr;
299    unsigned int remainder = 0;
300    size_t len = addlen;
301
302    dstptr = dst + (dstlen-1);
303    addptr = add + (addlen-1);
304    while (len) {
305        remainder += *dstptr + *addptr;
306        *dstptr = remainder & 0xff;
307        remainder >>= 8;
308        len--; dstptr--; addptr--;
309    }
310    len = dstlen - addlen;
311    while (len && remainder > 0) {
312        remainder = *dstptr + 1;
313        *dstptr = remainder & 0xff;
314        remainder >>= 8;
315        len--; dstptr--;
316    }
317}
318#endif /* defined(CONFIG_CRYPTO_DRBG_HASH) || defined(CONFIG_CRYPTO_DRBG_CTR) */
319
320/******************************************************************
321 * CTR DRBG callback functions
322 ******************************************************************/
323
324#ifdef CONFIG_CRYPTO_DRBG_CTR
325#define CRYPTO_DRBG_CTR_STRING "CTR "
326static int drbg_kcapi_sym(struct drbg_state *drbg, const unsigned char *key,
327              unsigned char *outval, const struct drbg_string *in);
328static int drbg_init_sym_kernel(struct drbg_state *drbg);
329static int drbg_fini_sym_kernel(struct drbg_state *drbg);
330
331/* BCC function for CTR DRBG as defined in 10.4.3 */
332static int drbg_ctr_bcc(struct drbg_state *drbg,
333            unsigned char *out, const unsigned char *key,
334            struct list_head *in)
335{
336    int ret = 0;
337    struct drbg_string *curr = NULL;
338    struct drbg_string data;
339    short cnt = 0;
340
341    drbg_string_fill(&data, out, drbg_blocklen(drbg));
342
343    /* 10.4.3 step 1 */
344    memset(out, 0, drbg_blocklen(drbg));
345
346    /* 10.4.3 step 2 / 4 */
347    list_for_each_entry(curr, in, list) {
348        const unsigned char *pos = curr->buf;
349        size_t len = curr->len;
350        /* 10.4.3 step 4.1 */
351        while (len) {
352            /* 10.4.3 step 4.2 */
353            if (drbg_blocklen(drbg) == cnt) {
354                cnt = 0;
355                ret = drbg_kcapi_sym(drbg, key, out, &data);
356                if (ret)
357                    return ret;
358            }
359            out[cnt] ^= *pos;
360            pos++;
361            cnt++;
362            len--;
363        }
364    }
365    /* 10.4.3 step 4.2 for last block */
366    if (cnt)
367        ret = drbg_kcapi_sym(drbg, key, out, &data);
368
369    return ret;
370}
371
372/*
373 * scratchpad usage: drbg_ctr_update is interlinked with drbg_ctr_df
374 * (and drbg_ctr_bcc, but this function does not need any temporary buffers),
375 * the scratchpad is used as follows:
376 * drbg_ctr_update:
377 * temp
378 * start: drbg->scratchpad
379 * length: drbg_statelen(drbg) + drbg_blocklen(drbg)
380 * note: the cipher writing into this variable works
381 * blocklen-wise. Now, when the statelen is not a multiple
382 * of blocklen, the generateion loop below "spills over"
383 * by at most blocklen. Thus, we need to give sufficient
384 * memory.
385 * df_data
386 * start: drbg->scratchpad +
387 * drbg_statelen(drbg) + drbg_blocklen(drbg)
388 * length: drbg_statelen(drbg)
389 *
390 * drbg_ctr_df:
391 * pad
392 * start: df_data + drbg_statelen(drbg)
393 * length: drbg_blocklen(drbg)
394 * iv
395 * start: pad + drbg_blocklen(drbg)
396 * length: drbg_blocklen(drbg)
397 * temp
398 * start: iv + drbg_blocklen(drbg)
399 * length: drbg_satelen(drbg) + drbg_blocklen(drbg)
400 * note: temp is the buffer that the BCC function operates
401 * on. BCC operates blockwise. drbg_statelen(drbg)
402 * is sufficient when the DRBG state length is a multiple
403 * of the block size. For AES192 (and maybe other ciphers)
404 * this is not correct and the length for temp is
405 * insufficient (yes, that also means for such ciphers,
406 * the final output of all BCC rounds are truncated).
407 * Therefore, add drbg_blocklen(drbg) to cover all
408 * possibilities.
409 */
410
411/* Derivation Function for CTR DRBG as defined in 10.4.2 */
412static int drbg_ctr_df(struct drbg_state *drbg,
413               unsigned char *df_data, size_t bytes_to_return,
414               struct list_head *seedlist)
415{
416    int ret = -EFAULT;
417    unsigned char L_N[8];
418    /* S3 is input */
419    struct drbg_string S1, S2, S4, cipherin;
420    LIST_HEAD(bcc_list);
421    unsigned char *pad = df_data + drbg_statelen(drbg);
422    unsigned char *iv = pad + drbg_blocklen(drbg);
423    unsigned char *temp = iv + drbg_blocklen(drbg);
424    size_t padlen = 0;
425    unsigned int templen = 0;
426    /* 10.4.2 step 7 */
427    unsigned int i = 0;
428    /* 10.4.2 step 8 */
429    const unsigned char *K = (unsigned char *)
430               "\x00\x01\x02\x03\x04\x05\x06\x07"
431               "\x08\x09\x0a\x0b\x0c\x0d\x0e\x0f"
432               "\x10\x11\x12\x13\x14\x15\x16\x17"
433               "\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f";
434    unsigned char *X;
435    size_t generated_len = 0;
436    size_t inputlen = 0;
437    struct drbg_string *seed = NULL;
438
439    memset(pad, 0, drbg_blocklen(drbg));
440    memset(iv, 0, drbg_blocklen(drbg));
441    memset(temp, 0, drbg_statelen(drbg));
442
443    /* 10.4.2 step 1 is implicit as we work byte-wise */
444
445    /* 10.4.2 step 2 */
446    if ((512/8) < bytes_to_return)
447        return -EINVAL;
448
449    /* 10.4.2 step 2 -- calculate the entire length of all input data */
450    list_for_each_entry(seed, seedlist, list)
451        inputlen += seed->len;
452    drbg_cpu_to_be32(inputlen, &L_N[0]);
453
454    /* 10.4.2 step 3 */
455    drbg_cpu_to_be32(bytes_to_return, &L_N[4]);
456
457    /* 10.4.2 step 5: length is L_N, input_string, one byte, padding */
458    padlen = (inputlen + sizeof(L_N) + 1) % (drbg_blocklen(drbg));
459    /* wrap the padlen appropriately */
460    if (padlen)
461        padlen = drbg_blocklen(drbg) - padlen;
462    /*
463     * pad / padlen contains the 0x80 byte and the following zero bytes.
464     * As the calculated padlen value only covers the number of zero
465     * bytes, this value has to be incremented by one for the 0x80 byte.
466     */
467    padlen++;
468    pad[0] = 0x80;
469
470    /* 10.4.2 step 4 -- first fill the linked list and then order it */
471    drbg_string_fill(&S1, iv, drbg_blocklen(drbg));
472    list_add_tail(&S1.list, &bcc_list);
473    drbg_string_fill(&S2, L_N, sizeof(L_N));
474    list_add_tail(&S2.list, &bcc_list);
475    list_splice_tail(seedlist, &bcc_list);
476    drbg_string_fill(&S4, pad, padlen);
477    list_add_tail(&S4.list, &bcc_list);
478
479    /* 10.4.2 step 9 */
480    while (templen < (drbg_keylen(drbg) + (drbg_blocklen(drbg)))) {
481        /*
482         * 10.4.2 step 9.1 - the padding is implicit as the buffer
483         * holds zeros after allocation -- even the increment of i
484         * is irrelevant as the increment remains within length of i
485         */
486        drbg_cpu_to_be32(i, iv);
487        /* 10.4.2 step 9.2 -- BCC and concatenation with temp */
488        ret = drbg_ctr_bcc(drbg, temp + templen, K, &bcc_list);
489        if (ret)
490            goto out;
491        /* 10.4.2 step 9.3 */
492        i++;
493        templen += drbg_blocklen(drbg);
494    }
495
496    /* 10.4.2 step 11 */
497    X = temp + (drbg_keylen(drbg));
498    drbg_string_fill(&cipherin, X, drbg_blocklen(drbg));
499
500    /* 10.4.2 step 12: overwriting of outval is implemented in next step */
501
502    /* 10.4.2 step 13 */
503    while (generated_len < bytes_to_return) {
504        short blocklen = 0;
505        /*
506         * 10.4.2 step 13.1: the truncation of the key length is
507         * implicit as the key is only drbg_blocklen in size based on
508         * the implementation of the cipher function callback
509         */
510        ret = drbg_kcapi_sym(drbg, temp, X, &cipherin);
511        if (ret)
512            goto out;
513        blocklen = (drbg_blocklen(drbg) <
514                (bytes_to_return - generated_len)) ?
515                drbg_blocklen(drbg) :
516                (bytes_to_return - generated_len);
517        /* 10.4.2 step 13.2 and 14 */
518        memcpy(df_data + generated_len, X, blocklen);
519        generated_len += blocklen;
520    }
521
522    ret = 0;
523
524out:
525    memset(iv, 0, drbg_blocklen(drbg));
526    memset(temp, 0, drbg_statelen(drbg));
527    memset(pad, 0, drbg_blocklen(drbg));
528    return ret;
529}
530
531/*
532 * update function of CTR DRBG as defined in 10.2.1.2
533 *
534 * The reseed variable has an enhanced meaning compared to the update
535 * functions of the other DRBGs as follows:
536 * 0 => initial seed from initialization
537 * 1 => reseed via drbg_seed
538 * 2 => first invocation from drbg_ctr_update when addtl is present. In
539 * this case, the df_data scratchpad is not deleted so that it is
540 * available for another calls to prevent calling the DF function
541 * again.
542 * 3 => second invocation from drbg_ctr_update. When the update function
543 * was called with addtl, the df_data memory already contains the
544 * DFed addtl information and we do not need to call DF again.
545 */
546static int drbg_ctr_update(struct drbg_state *drbg, struct list_head *seed,
547               int reseed)
548{
549    int ret = -EFAULT;
550    /* 10.2.1.2 step 1 */
551    unsigned char *temp = drbg->scratchpad;
552    unsigned char *df_data = drbg->scratchpad + drbg_statelen(drbg) +
553                 drbg_blocklen(drbg);
554    unsigned char *temp_p, *df_data_p; /* pointer to iterate over buffers */
555    unsigned int len = 0;
556    struct drbg_string cipherin;
557    unsigned char prefix = DRBG_PREFIX1;
558
559    memset(temp, 0, drbg_statelen(drbg) + drbg_blocklen(drbg));
560    if (3 > reseed)
561        memset(df_data, 0, drbg_statelen(drbg));
562
563    /* 10.2.1.3.2 step 2 and 10.2.1.4.2 step 2 */
564    if (seed) {
565        ret = drbg_ctr_df(drbg, df_data, drbg_statelen(drbg), seed);
566        if (ret)
567            goto out;
568    }
569
570    drbg_string_fill(&cipherin, drbg->V, drbg_blocklen(drbg));
571    /*
572     * 10.2.1.3.2 steps 2 and 3 are already covered as the allocation
573     * zeroizes all memory during initialization
574     */
575    while (len < (drbg_statelen(drbg))) {
576        /* 10.2.1.2 step 2.1 */
577        drbg_add_buf(drbg->V, drbg_blocklen(drbg), &prefix, 1);
578        /*
579         * 10.2.1.2 step 2.2 */
580        ret = drbg_kcapi_sym(drbg, drbg->C, temp + len, &cipherin);
581        if (ret)
582            goto out;
583        /* 10.2.1.2 step 2.3 and 3 */
584        len += drbg_blocklen(drbg);
585    }
586
587    /* 10.2.1.2 step 4 */
588    temp_p = temp;
589    df_data_p = df_data;
590    for (len = 0; len < drbg_statelen(drbg); len++) {
591        *temp_p ^= *df_data_p;
592        df_data_p++; temp_p++;
593    }
594
595    /* 10.2.1.2 step 5 */
596    memcpy(drbg->C, temp, drbg_keylen(drbg));
597    /* 10.2.1.2 step 6 */
598    memcpy(drbg->V, temp + drbg_keylen(drbg), drbg_blocklen(drbg));
599    ret = 0;
600
601out:
602    memset(temp, 0, drbg_statelen(drbg) + drbg_blocklen(drbg));
603    if (2 != reseed)
604        memset(df_data, 0, drbg_statelen(drbg));
605    return ret;
606}
607
608/*
609 * scratchpad use: drbg_ctr_update is called independently from
610 * drbg_ctr_extract_bytes. Therefore, the scratchpad is reused
611 */
612/* Generate function of CTR DRBG as defined in 10.2.1.5.2 */
613static int drbg_ctr_generate(struct drbg_state *drbg,
614                 unsigned char *buf, unsigned int buflen,
615                 struct list_head *addtl)
616{
617    int len = 0;
618    int ret = 0;
619    struct drbg_string data;
620    unsigned char prefix = DRBG_PREFIX1;
621
622    memset(drbg->scratchpad, 0, drbg_blocklen(drbg));
623
624    /* 10.2.1.5.2 step 2 */
625    if (addtl && !list_empty(addtl)) {
626        ret = drbg_ctr_update(drbg, addtl, 2);
627        if (ret)
628            return 0;
629    }
630
631    /* 10.2.1.5.2 step 4.1 */
632    drbg_add_buf(drbg->V, drbg_blocklen(drbg), &prefix, 1);
633    drbg_string_fill(&data, drbg->V, drbg_blocklen(drbg));
634    while (len < buflen) {
635        int outlen = 0;
636        /* 10.2.1.5.2 step 4.2 */
637        ret = drbg_kcapi_sym(drbg, drbg->C, drbg->scratchpad, &data);
638        if (ret) {
639            len = ret;
640            goto out;
641        }
642        outlen = (drbg_blocklen(drbg) < (buflen - len)) ?
643              drbg_blocklen(drbg) : (buflen - len);
644        if (!drbg_fips_continuous_test(drbg, drbg->scratchpad)) {
645            /* 10.2.1.5.2 step 6 */
646            drbg_add_buf(drbg->V, drbg_blocklen(drbg), &prefix, 1);
647            continue;
648        }
649        /* 10.2.1.5.2 step 4.3 */
650        memcpy(buf + len, drbg->scratchpad, outlen);
651        len += outlen;
652        /* 10.2.1.5.2 step 6 */
653        if (len < buflen)
654            drbg_add_buf(drbg->V, drbg_blocklen(drbg), &prefix, 1);
655    }
656
657    /* 10.2.1.5.2 step 6 */
658    ret = drbg_ctr_update(drbg, NULL, 3);
659    if (ret)
660        len = ret;
661
662out:
663    memset(drbg->scratchpad, 0, drbg_blocklen(drbg));
664    return len;
665}
666
667static struct drbg_state_ops drbg_ctr_ops = {
668    .update = drbg_ctr_update,
669    .generate = drbg_ctr_generate,
670    .crypto_init = drbg_init_sym_kernel,
671    .crypto_fini = drbg_fini_sym_kernel,
672};
673#endif /* CONFIG_CRYPTO_DRBG_CTR */
674
675/******************************************************************
676 * HMAC DRBG callback functions
677 ******************************************************************/
678
679#if defined(CONFIG_CRYPTO_DRBG_HASH) || defined(CONFIG_CRYPTO_DRBG_HMAC)
680static int drbg_kcapi_hash(struct drbg_state *drbg, const unsigned char *key,
681               unsigned char *outval, const struct list_head *in);
682static int drbg_init_hash_kernel(struct drbg_state *drbg);
683static int drbg_fini_hash_kernel(struct drbg_state *drbg);
684#endif /* (CONFIG_CRYPTO_DRBG_HASH || CONFIG_CRYPTO_DRBG_HMAC) */
685
686#ifdef CONFIG_CRYPTO_DRBG_HMAC
687#define CRYPTO_DRBG_HMAC_STRING "HMAC "
688/* update function of HMAC DRBG as defined in 10.1.2.2 */
689static int drbg_hmac_update(struct drbg_state *drbg, struct list_head *seed,
690                int reseed)
691{
692    int ret = -EFAULT;
693    int i = 0;
694    struct drbg_string seed1, seed2, vdata;
695    LIST_HEAD(seedlist);
696    LIST_HEAD(vdatalist);
697
698    if (!reseed)
699        /* 10.1.2.3 step 2 -- memset(0) of C is implicit with kzalloc */
700        memset(drbg->V, 1, drbg_statelen(drbg));
701
702    drbg_string_fill(&seed1, drbg->V, drbg_statelen(drbg));
703    list_add_tail(&seed1.list, &seedlist);
704    /* buffer of seed2 will be filled in for loop below with one byte */
705    drbg_string_fill(&seed2, NULL, 1);
706    list_add_tail(&seed2.list, &seedlist);
707    /* input data of seed is allowed to be NULL at this point */
708    if (seed)
709        list_splice_tail(seed, &seedlist);
710
711    drbg_string_fill(&vdata, drbg->V, drbg_statelen(drbg));
712    list_add_tail(&vdata.list, &vdatalist);
713    for (i = 2; 0 < i; i--) {
714        /* first round uses 0x0, second 0x1 */
715        unsigned char prefix = DRBG_PREFIX0;
716        if (1 == i)
717            prefix = DRBG_PREFIX1;
718        /* 10.1.2.2 step 1 and 4 -- concatenation and HMAC for key */
719        seed2.buf = &prefix;
720        ret = drbg_kcapi_hash(drbg, drbg->C, drbg->C, &seedlist);
721        if (ret)
722            return ret;
723
724        /* 10.1.2.2 step 2 and 5 -- HMAC for V */
725        ret = drbg_kcapi_hash(drbg, drbg->C, drbg->V, &vdatalist);
726        if (ret)
727            return ret;
728
729        /* 10.1.2.2 step 3 */
730        if (!seed)
731            return ret;
732    }
733
734    return 0;
735}
736
737/* generate function of HMAC DRBG as defined in 10.1.2.5 */
738static int drbg_hmac_generate(struct drbg_state *drbg,
739                  unsigned char *buf,
740                  unsigned int buflen,
741                  struct list_head *addtl)
742{
743    int len = 0;
744    int ret = 0;
745    struct drbg_string data;
746    LIST_HEAD(datalist);
747
748    /* 10.1.2.5 step 2 */
749    if (addtl && !list_empty(addtl)) {
750        ret = drbg_hmac_update(drbg, addtl, 1);
751        if (ret)
752            return ret;
753    }
754
755    drbg_string_fill(&data, drbg->V, drbg_statelen(drbg));
756    list_add_tail(&data.list, &datalist);
757    while (len < buflen) {
758        unsigned int outlen = 0;
759        /* 10.1.2.5 step 4.1 */
760        ret = drbg_kcapi_hash(drbg, drbg->C, drbg->V, &datalist);
761        if (ret)
762            return ret;
763        outlen = (drbg_blocklen(drbg) < (buflen - len)) ?
764              drbg_blocklen(drbg) : (buflen - len);
765        if (!drbg_fips_continuous_test(drbg, drbg->V))
766            continue;
767
768        /* 10.1.2.5 step 4.2 */
769        memcpy(buf + len, drbg->V, outlen);
770        len += outlen;
771    }
772
773    /* 10.1.2.5 step 6 */
774    if (addtl && !list_empty(addtl))
775        ret = drbg_hmac_update(drbg, addtl, 1);
776    else
777        ret = drbg_hmac_update(drbg, NULL, 1);
778    if (ret)
779        return ret;
780
781    return len;
782}
783
784static struct drbg_state_ops drbg_hmac_ops = {
785    .update = drbg_hmac_update,
786    .generate = drbg_hmac_generate,
787    .crypto_init = drbg_init_hash_kernel,
788    .crypto_fini = drbg_fini_hash_kernel,
789
790};
791#endif /* CONFIG_CRYPTO_DRBG_HMAC */
792
793/******************************************************************
794 * Hash DRBG callback functions
795 ******************************************************************/
796
797#ifdef CONFIG_CRYPTO_DRBG_HASH
798#define CRYPTO_DRBG_HASH_STRING "HASH "
799/*
800 * scratchpad usage: as drbg_hash_update and drbg_hash_df are used
801 * interlinked, the scratchpad is used as follows:
802 * drbg_hash_update
803 * start: drbg->scratchpad
804 * length: drbg_statelen(drbg)
805 * drbg_hash_df:
806 * start: drbg->scratchpad + drbg_statelen(drbg)
807 * length: drbg_blocklen(drbg)
808 *
809 * drbg_hash_process_addtl uses the scratchpad, but fully completes
810 * before either of the functions mentioned before are invoked. Therefore,
811 * drbg_hash_process_addtl does not need to be specifically considered.
812 */
813
814/* Derivation Function for Hash DRBG as defined in 10.4.1 */
815static int drbg_hash_df(struct drbg_state *drbg,
816            unsigned char *outval, size_t outlen,
817            struct list_head *entropylist)
818{
819    int ret = 0;
820    size_t len = 0;
821    unsigned char input[5];
822    unsigned char *tmp = drbg->scratchpad + drbg_statelen(drbg);
823    struct drbg_string data;
824
825    memset(tmp, 0, drbg_blocklen(drbg));
826
827    /* 10.4.1 step 3 */
828    input[0] = 1;
829    drbg_cpu_to_be32((outlen * 8), &input[1]);
830
831    /* 10.4.1 step 4.1 -- concatenation of data for input into hash */
832    drbg_string_fill(&data, input, 5);
833    list_add(&data.list, entropylist);
834
835    /* 10.4.1 step 4 */
836    while (len < outlen) {
837        short blocklen = 0;
838        /* 10.4.1 step 4.1 */
839        ret = drbg_kcapi_hash(drbg, NULL, tmp, entropylist);
840        if (ret)
841            goto out;
842        /* 10.4.1 step 4.2 */
843        input[0]++;
844        blocklen = (drbg_blocklen(drbg) < (outlen - len)) ?
845                drbg_blocklen(drbg) : (outlen - len);
846        memcpy(outval + len, tmp, blocklen);
847        len += blocklen;
848    }
849
850out:
851    memset(tmp, 0, drbg_blocklen(drbg));
852    return ret;
853}
854
855/* update function for Hash DRBG as defined in 10.1.1.2 / 10.1.1.3 */
856static int drbg_hash_update(struct drbg_state *drbg, struct list_head *seed,
857                int reseed)
858{
859    int ret = 0;
860    struct drbg_string data1, data2;
861    LIST_HEAD(datalist);
862    LIST_HEAD(datalist2);
863    unsigned char *V = drbg->scratchpad;
864    unsigned char prefix = DRBG_PREFIX1;
865
866    memset(drbg->scratchpad, 0, drbg_statelen(drbg));
867    if (!seed)
868        return -EINVAL;
869
870    if (reseed) {
871        /* 10.1.1.3 step 1 */
872        memcpy(V, drbg->V, drbg_statelen(drbg));
873        drbg_string_fill(&data1, &prefix, 1);
874        list_add_tail(&data1.list, &datalist);
875        drbg_string_fill(&data2, V, drbg_statelen(drbg));
876        list_add_tail(&data2.list, &datalist);
877    }
878    list_splice_tail(seed, &datalist);
879
880    /* 10.1.1.2 / 10.1.1.3 step 2 and 3 */
881    ret = drbg_hash_df(drbg, drbg->V, drbg_statelen(drbg), &datalist);
882    if (ret)
883        goto out;
884
885    /* 10.1.1.2 / 10.1.1.3 step 4 */
886    prefix = DRBG_PREFIX0;
887    drbg_string_fill(&data1, &prefix, 1);
888    list_add_tail(&data1.list, &datalist2);
889    drbg_string_fill(&data2, drbg->V, drbg_statelen(drbg));
890    list_add_tail(&data2.list, &datalist2);
891    /* 10.1.1.2 / 10.1.1.3 step 4 */
892    ret = drbg_hash_df(drbg, drbg->C, drbg_statelen(drbg), &datalist2);
893
894out:
895    memset(drbg->scratchpad, 0, drbg_statelen(drbg));
896    return ret;
897}
898
899/* processing of additional information string for Hash DRBG */
900static int drbg_hash_process_addtl(struct drbg_state *drbg,
901                   struct list_head *addtl)
902{
903    int ret = 0;
904    struct drbg_string data1, data2;
905    LIST_HEAD(datalist);
906    unsigned char prefix = DRBG_PREFIX2;
907
908    /* this is value w as per documentation */
909    memset(drbg->scratchpad, 0, drbg_blocklen(drbg));
910
911    /* 10.1.1.4 step 2 */
912    if (!addtl || list_empty(addtl))
913        return 0;
914
915    /* 10.1.1.4 step 2a */
916    drbg_string_fill(&data1, &prefix, 1);
917    drbg_string_fill(&data2, drbg->V, drbg_statelen(drbg));
918    list_add_tail(&data1.list, &datalist);
919    list_add_tail(&data2.list, &datalist);
920    list_splice_tail(addtl, &datalist);
921    ret = drbg_kcapi_hash(drbg, NULL, drbg->scratchpad, &datalist);
922    if (ret)
923        goto out;
924
925    /* 10.1.1.4 step 2b */
926    drbg_add_buf(drbg->V, drbg_statelen(drbg),
927             drbg->scratchpad, drbg_blocklen(drbg));
928
929out:
930    memset(drbg->scratchpad, 0, drbg_blocklen(drbg));
931    return ret;
932}
933
934/* Hashgen defined in 10.1.1.4 */
935static int drbg_hash_hashgen(struct drbg_state *drbg,
936                 unsigned char *buf,
937                 unsigned int buflen)
938{
939    int len = 0;
940    int ret = 0;
941    unsigned char *src = drbg->scratchpad;
942    unsigned char *dst = drbg->scratchpad + drbg_statelen(drbg);
943    struct drbg_string data;
944    LIST_HEAD(datalist);
945    unsigned char prefix = DRBG_PREFIX1;
946
947    memset(src, 0, drbg_statelen(drbg));
948    memset(dst, 0, drbg_blocklen(drbg));
949
950    /* 10.1.1.4 step hashgen 2 */
951    memcpy(src, drbg->V, drbg_statelen(drbg));
952
953    drbg_string_fill(&data, src, drbg_statelen(drbg));
954    list_add_tail(&data.list, &datalist);
955    while (len < buflen) {
956        unsigned int outlen = 0;
957        /* 10.1.1.4 step hashgen 4.1 */
958        ret = drbg_kcapi_hash(drbg, NULL, dst, &datalist);
959        if (ret) {
960            len = ret;
961            goto out;
962        }
963        outlen = (drbg_blocklen(drbg) < (buflen - len)) ?
964              drbg_blocklen(drbg) : (buflen - len);
965        if (!drbg_fips_continuous_test(drbg, dst)) {
966            drbg_add_buf(src, drbg_statelen(drbg), &prefix, 1);
967            continue;
968        }
969        /* 10.1.1.4 step hashgen 4.2 */
970        memcpy(buf + len, dst, outlen);
971        len += outlen;
972        /* 10.1.1.4 hashgen step 4.3 */
973        if (len < buflen)
974            drbg_add_buf(src, drbg_statelen(drbg), &prefix, 1);
975    }
976
977out:
978    memset(drbg->scratchpad, 0,
979           (drbg_statelen(drbg) + drbg_blocklen(drbg)));
980    return len;
981}
982
983/* generate function for Hash DRBG as defined in 10.1.1.4 */
984static int drbg_hash_generate(struct drbg_state *drbg,
985                  unsigned char *buf, unsigned int buflen,
986                  struct list_head *addtl)
987{
988    int len = 0;
989    int ret = 0;
990    union {
991        unsigned char req[8];
992        __be64 req_int;
993    } u;
994    unsigned char prefix = DRBG_PREFIX3;
995    struct drbg_string data1, data2;
996    LIST_HEAD(datalist);
997
998    /* 10.1.1.4 step 2 */
999    ret = drbg_hash_process_addtl(drbg, addtl);
1000    if (ret)
1001        return ret;
1002    /* 10.1.1.4 step 3 */
1003    len = drbg_hash_hashgen(drbg, buf, buflen);
1004
1005    /* this is the value H as documented in 10.1.1.4 */
1006    memset(drbg->scratchpad, 0, drbg_blocklen(drbg));
1007    /* 10.1.1.4 step 4 */
1008    drbg_string_fill(&data1, &prefix, 1);
1009    list_add_tail(&data1.list, &datalist);
1010    drbg_string_fill(&data2, drbg->V, drbg_statelen(drbg));
1011    list_add_tail(&data2.list, &datalist);
1012    ret = drbg_kcapi_hash(drbg, NULL, drbg->scratchpad, &datalist);
1013    if (ret) {
1014        len = ret;
1015        goto out;
1016    }
1017
1018    /* 10.1.1.4 step 5 */
1019    drbg_add_buf(drbg->V, drbg_statelen(drbg),
1020             drbg->scratchpad, drbg_blocklen(drbg));
1021    drbg_add_buf(drbg->V, drbg_statelen(drbg),
1022             drbg->C, drbg_statelen(drbg));
1023    u.req_int = cpu_to_be64(drbg->reseed_ctr);
1024    drbg_add_buf(drbg->V, drbg_statelen(drbg), u.req, 8);
1025
1026out:
1027    memset(drbg->scratchpad, 0, drbg_blocklen(drbg));
1028    return len;
1029}
1030
1031/*
1032 * scratchpad usage: as update and generate are used isolated, both
1033 * can use the scratchpad
1034 */
1035static struct drbg_state_ops drbg_hash_ops = {
1036    .update = drbg_hash_update,
1037    .generate = drbg_hash_generate,
1038    .crypto_init = drbg_init_hash_kernel,
1039    .crypto_fini = drbg_fini_hash_kernel,
1040};
1041#endif /* CONFIG_CRYPTO_DRBG_HASH */
1042
1043/******************************************************************
1044 * Functions common for DRBG implementations
1045 ******************************************************************/
1046
1047/*
1048 * Seeding or reseeding of the DRBG
1049 *
1050 * @drbg: DRBG state struct
1051 * @pers: personalization / additional information buffer
1052 * @reseed: 0 for initial seed process, 1 for reseeding
1053 *
1054 * return:
1055 * 0 on success
1056 * error value otherwise
1057 */
1058static int drbg_seed(struct drbg_state *drbg, struct drbg_string *pers,
1059             bool reseed)
1060{
1061    int ret = 0;
1062    unsigned char *entropy = NULL;
1063    size_t entropylen = 0;
1064    struct drbg_string data1;
1065    LIST_HEAD(seedlist);
1066
1067    /* 9.1 / 9.2 / 9.3.1 step 3 */
1068    if (pers && pers->len > (drbg_max_addtl(drbg))) {
1069        pr_devel("DRBG: personalization string too long %zu\n",
1070             pers->len);
1071        return -EINVAL;
1072    }
1073
1074    if (drbg->test_data && drbg->test_data->testentropy) {
1075        drbg_string_fill(&data1, drbg->test_data->testentropy->buf,
1076                 drbg->test_data->testentropy->len);
1077        pr_devel("DRBG: using test entropy\n");
1078    } else {
1079        /*
1080         * Gather entropy equal to the security strength of the DRBG.
1081         * With a derivation function, a nonce is required in addition
1082         * to the entropy. A nonce must be at least 1/2 of the security
1083         * strength of the DRBG in size. Thus, entropy * nonce is 3/2
1084         * of the strength. The consideration of a nonce is only
1085         * applicable during initial seeding.
1086         */
1087        entropylen = drbg_sec_strength(drbg->core->flags);
1088        if (!entropylen)
1089            return -EFAULT;
1090        if (!reseed)
1091            entropylen = ((entropylen + 1) / 2) * 3;
1092        pr_devel("DRBG: (re)seeding with %zu bytes of entropy\n",
1093             entropylen);
1094        entropy = kzalloc(entropylen, GFP_KERNEL);
1095        if (!entropy)
1096            return -ENOMEM;
1097        get_random_bytes(entropy, entropylen);
1098        drbg_string_fill(&data1, entropy, entropylen);
1099    }
1100    list_add_tail(&data1.list, &seedlist);
1101
1102    /*
1103     * concatenation of entropy with personalization str / addtl input)
1104     * the variable pers is directly handed in by the caller, so check its
1105     * contents whether it is appropriate
1106     */
1107    if (pers && pers->buf && 0 < pers->len) {
1108        list_add_tail(&pers->list, &seedlist);
1109        pr_devel("DRBG: using personalization string\n");
1110    }
1111
1112    if (!reseed) {
1113        memset(drbg->V, 0, drbg_statelen(drbg));
1114        memset(drbg->C, 0, drbg_statelen(drbg));
1115    }
1116
1117    ret = drbg->d_ops->update(drbg, &seedlist, reseed);
1118    if (ret)
1119        goto out;
1120
1121    drbg->seeded = true;
1122    /* 10.1.1.2 / 10.1.1.3 step 5 */
1123    drbg->reseed_ctr = 1;
1124
1125out:
1126    kzfree(entropy);
1127    return ret;
1128}
1129
1130/* Free all substructures in a DRBG state without the DRBG state structure */
1131static inline void drbg_dealloc_state(struct drbg_state *drbg)
1132{
1133    if (!drbg)
1134        return;
1135    kzfree(drbg->V);
1136    drbg->V = NULL;
1137    kzfree(drbg->C);
1138    drbg->C = NULL;
1139    kzfree(drbg->scratchpad);
1140    drbg->scratchpad = NULL;
1141    drbg->reseed_ctr = 0;
1142#ifdef CONFIG_CRYPTO_FIPS
1143    kzfree(drbg->prev);
1144    drbg->prev = NULL;
1145    drbg->fips_primed = false;
1146#endif
1147}
1148
1149/*
1150 * Allocate all sub-structures for a DRBG state.
1151 * The DRBG state structure must already be allocated.
1152 */
1153static inline int drbg_alloc_state(struct drbg_state *drbg)
1154{
1155    int ret = -ENOMEM;
1156    unsigned int sb_size = 0;
1157
1158    drbg->V = kmalloc(drbg_statelen(drbg), GFP_KERNEL);
1159    if (!drbg->V)
1160        goto err;
1161    drbg->C = kmalloc(drbg_statelen(drbg), GFP_KERNEL);
1162    if (!drbg->C)
1163        goto err;
1164#ifdef CONFIG_CRYPTO_FIPS
1165    drbg->prev = kmalloc(drbg_blocklen(drbg), GFP_KERNEL);
1166    if (!drbg->prev)
1167        goto err;
1168    drbg->fips_primed = false;
1169#endif
1170    /* scratchpad is only generated for CTR and Hash */
1171    if (drbg->core->flags & DRBG_HMAC)
1172        sb_size = 0;
1173    else if (drbg->core->flags & DRBG_CTR)
1174        sb_size = drbg_statelen(drbg) + drbg_blocklen(drbg) + /* temp */
1175              drbg_statelen(drbg) + /* df_data */
1176              drbg_blocklen(drbg) + /* pad */
1177              drbg_blocklen(drbg) + /* iv */
1178              drbg_statelen(drbg) + drbg_blocklen(drbg); /* temp */
1179    else
1180        sb_size = drbg_statelen(drbg) + drbg_blocklen(drbg);
1181
1182    if (0 < sb_size) {
1183        drbg->scratchpad = kzalloc(sb_size, GFP_KERNEL);
1184        if (!drbg->scratchpad)
1185            goto err;
1186    }
1187    spin_lock_init(&drbg->drbg_lock);
1188    return 0;
1189
1190err:
1191    drbg_dealloc_state(drbg);
1192    return ret;
1193}
1194
1195/*
1196 * Strategy to avoid holding long term locks: generate a shadow copy of DRBG
1197 * and perform all operations on this shadow copy. After finishing, restore
1198 * the updated state of the shadow copy into original drbg state. This way,
1199 * only the read and write operations of the original drbg state must be
1200 * locked
1201 */
1202static inline void drbg_copy_drbg(struct drbg_state *src,
1203                  struct drbg_state *dst)
1204{
1205    if (!src || !dst)
1206        return;
1207    memcpy(dst->V, src->V, drbg_statelen(src));
1208    memcpy(dst->C, src->C, drbg_statelen(src));
1209    dst->reseed_ctr = src->reseed_ctr;
1210    dst->seeded = src->seeded;
1211    dst->pr = src->pr;
1212#ifdef CONFIG_CRYPTO_FIPS
1213    dst->fips_primed = src->fips_primed;
1214    memcpy(dst->prev, src->prev, drbg_blocklen(src));
1215#endif
1216    /*
1217     * Not copied:
1218     * scratchpad is initialized drbg_alloc_state;
1219     * priv_data is initialized with call to crypto_init;
1220     * d_ops and core are set outside, as these parameters are const;
1221     * test_data is set outside to prevent it being copied back.
1222     */
1223}
1224
1225static int drbg_make_shadow(struct drbg_state *drbg, struct drbg_state **shadow)
1226{
1227    int ret = -ENOMEM;
1228    struct drbg_state *tmp = NULL;
1229
1230    tmp = kzalloc(sizeof(struct drbg_state), GFP_KERNEL);
1231    if (!tmp)
1232        return -ENOMEM;
1233
1234    /* read-only data as they are defined as const, no lock needed */
1235    tmp->core = drbg->core;
1236    tmp->d_ops = drbg->d_ops;
1237
1238    ret = drbg_alloc_state(tmp);
1239    if (ret)
1240        goto err;
1241
1242    spin_lock_bh(&drbg->drbg_lock);
1243    drbg_copy_drbg(drbg, tmp);
1244    /* only make a link to the test buffer, as we only read that data */
1245    tmp->test_data = drbg->test_data;
1246    spin_unlock_bh(&drbg->drbg_lock);
1247    *shadow = tmp;
1248    return 0;
1249
1250err:
1251    kzfree(tmp);
1252    return ret;
1253}
1254
1255static void drbg_restore_shadow(struct drbg_state *drbg,
1256                struct drbg_state **shadow)
1257{
1258    struct drbg_state *tmp = *shadow;
1259
1260    spin_lock_bh(&drbg->drbg_lock);
1261    drbg_copy_drbg(tmp, drbg);
1262    spin_unlock_bh(&drbg->drbg_lock);
1263    drbg_dealloc_state(tmp);
1264    kzfree(tmp);
1265    *shadow = NULL;
1266}
1267
1268/*************************************************************************
1269 * DRBG interface functions
1270 *************************************************************************/
1271
1272/*
1273 * DRBG generate function as required by SP800-90A - this function
1274 * generates random numbers
1275 *
1276 * @drbg DRBG state handle
1277 * @buf Buffer where to store the random numbers -- the buffer must already
1278 * be pre-allocated by caller
1279 * @buflen Length of output buffer - this value defines the number of random
1280 * bytes pulled from DRBG
1281 * @addtl Additional input that is mixed into state, may be NULL -- note
1282 * the entropy is pulled by the DRBG internally unconditionally
1283 * as defined in SP800-90A. The additional input is mixed into
1284 * the state in addition to the pulled entropy.
1285 *
1286 * return: generated number of bytes
1287 */
1288static int drbg_generate(struct drbg_state *drbg,
1289             unsigned char *buf, unsigned int buflen,
1290             struct drbg_string *addtl)
1291{
1292    int len = 0;
1293    struct drbg_state *shadow = NULL;
1294    LIST_HEAD(addtllist);
1295    struct drbg_string timestamp;
1296    union {
1297        cycles_t cycles;
1298        unsigned char char_cycles[sizeof(cycles_t)];
1299    } now;
1300
1301    if (0 == buflen || !buf) {
1302        pr_devel("DRBG: no output buffer provided\n");
1303        return -EINVAL;
1304    }
1305    if (addtl && NULL == addtl->buf && 0 < addtl->len) {
1306        pr_devel("DRBG: wrong format of additional information\n");
1307        return -EINVAL;
1308    }
1309
1310    len = drbg_make_shadow(drbg, &shadow);
1311    if (len) {
1312        pr_devel("DRBG: shadow copy cannot be generated\n");
1313        return len;
1314    }
1315
1316    /* 9.3.1 step 2 */
1317    len = -EINVAL;
1318    if (buflen > (drbg_max_request_bytes(shadow))) {
1319        pr_devel("DRBG: requested random numbers too large %u\n",
1320             buflen);
1321        goto err;
1322    }
1323
1324    /* 9.3.1 step 3 is implicit with the chosen DRBG */
1325
1326    /* 9.3.1 step 4 */
1327    if (addtl && addtl->len > (drbg_max_addtl(shadow))) {
1328        pr_devel("DRBG: additional information string too long %zu\n",
1329             addtl->len);
1330        goto err;
1331    }
1332    /* 9.3.1 step 5 is implicit with the chosen DRBG */
1333
1334    /*
1335     * 9.3.1 step 6 and 9 supplemented by 9.3.2 step c is implemented
1336     * here. The spec is a bit convoluted here, we make it simpler.
1337     */
1338    if ((drbg_max_requests(shadow)) < shadow->reseed_ctr)
1339        shadow->seeded = false;
1340
1341    /* allocate cipher handle */
1342    len = shadow->d_ops->crypto_init(shadow);
1343    if (len)
1344        goto err;
1345
1346    if (shadow->pr || !shadow->seeded) {
1347        pr_devel("DRBG: reseeding before generation (prediction "
1348             "resistance: %s, state %s)\n",
1349             drbg->pr ? "true" : "false",
1350             drbg->seeded ? "seeded" : "unseeded");
1351        /* 9.3.1 steps 7.1 through 7.3 */
1352        len = drbg_seed(shadow, addtl, true);
1353        if (len)
1354            goto err;
1355        /* 9.3.1 step 7.4 */
1356        addtl = NULL;
1357    }
1358
1359    /*
1360     * Mix the time stamp into the DRBG state if the DRBG is not in
1361     * test mode. If there are two callers invoking the DRBG at the same
1362     * time, i.e. before the first caller merges its shadow state back,
1363     * both callers would obtain the same random number stream without
1364     * changing the state here.
1365     */
1366    if (!drbg->test_data) {
1367        now.cycles = random_get_entropy();
1368        drbg_string_fill(&timestamp, now.char_cycles, sizeof(cycles_t));
1369        list_add_tail(&timestamp.list, &addtllist);
1370    }
1371    if (addtl && 0 < addtl->len)
1372        list_add_tail(&addtl->list, &addtllist);
1373    /* 9.3.1 step 8 and 10 */
1374    len = shadow->d_ops->generate(shadow, buf, buflen, &addtllist);
1375
1376    /* 10.1.1.4 step 6, 10.1.2.5 step 7, 10.2.1.5.2 step 7 */
1377    shadow->reseed_ctr++;
1378    if (0 >= len)
1379        goto err;
1380
1381    /*
1382     * Section 11.3.3 requires to re-perform self tests after some
1383     * generated random numbers. The chosen value after which self
1384     * test is performed is arbitrary, but it should be reasonable.
1385     * However, we do not perform the self tests because of the following
1386     * reasons: it is mathematically impossible that the initial self tests
1387     * were successfully and the following are not. If the initial would
1388     * pass and the following would not, the kernel integrity is violated.
1389     * In this case, the entire kernel operation is questionable and it
1390     * is unlikely that the integrity violation only affects the
1391     * correct operation of the DRBG.
1392     *
1393     * Albeit the following code is commented out, it is provided in
1394     * case somebody has a need to implement the test of 11.3.3.
1395     */
1396#if 0
1397    if (shadow->reseed_ctr && !(shadow->reseed_ctr % 4096)) {
1398        int err = 0;
1399        pr_devel("DRBG: start to perform self test\n");
1400        if (drbg->core->flags & DRBG_HMAC)
1401            err = alg_test("drbg_pr_hmac_sha256",
1402                       "drbg_pr_hmac_sha256", 0, 0);
1403        else if (drbg->core->flags & DRBG_CTR)
1404            err = alg_test("drbg_pr_ctr_aes128",
1405                       "drbg_pr_ctr_aes128", 0, 0);
1406        else
1407            err = alg_test("drbg_pr_sha256",
1408                       "drbg_pr_sha256", 0, 0);
1409        if (err) {
1410            pr_err("DRBG: periodical self test failed\n");
1411            /*
1412             * uninstantiate implies that from now on, only errors
1413             * are returned when reusing this DRBG cipher handle
1414             */
1415            drbg_uninstantiate(drbg);
1416            drbg_dealloc_state(shadow);
1417            kzfree(shadow);
1418            return 0;
1419        } else {
1420            pr_devel("DRBG: self test successful\n");
1421        }
1422    }
1423#endif
1424
1425err:
1426    shadow->d_ops->crypto_fini(shadow);
1427    drbg_restore_shadow(drbg, &shadow);
1428    return len;
1429}
1430
1431/*
1432 * Wrapper around drbg_generate which can pull arbitrary long strings
1433 * from the DRBG without hitting the maximum request limitation.
1434 *
1435 * Parameters: see drbg_generate
1436 * Return codes: see drbg_generate -- if one drbg_generate request fails,
1437 * the entire drbg_generate_long request fails
1438 */
1439static int drbg_generate_long(struct drbg_state *drbg,
1440                  unsigned char *buf, unsigned int buflen,
1441                  struct drbg_string *addtl)
1442{
1443    int len = 0;
1444    unsigned int slice = 0;
1445    do {
1446        int tmplen = 0;
1447        unsigned int chunk = 0;
1448        slice = ((buflen - len) / drbg_max_request_bytes(drbg));
1449        chunk = slice ? drbg_max_request_bytes(drbg) : (buflen - len);
1450        tmplen = drbg_generate(drbg, buf + len, chunk, addtl);
1451        if (0 >= tmplen)
1452            return tmplen;
1453        len += tmplen;
1454    } while (slice > 0 && (len < buflen));
1455    return len;
1456}
1457
1458/*
1459 * DRBG instantiation function as required by SP800-90A - this function
1460 * sets up the DRBG handle, performs the initial seeding and all sanity
1461 * checks required by SP800-90A
1462 *
1463 * @drbg memory of state -- if NULL, new memory is allocated
1464 * @pers Personalization string that is mixed into state, may be NULL -- note
1465 * the entropy is pulled by the DRBG internally unconditionally
1466 * as defined in SP800-90A. The additional input is mixed into
1467 * the state in addition to the pulled entropy.
1468 * @coreref reference to core
1469 * @pr prediction resistance enabled
1470 *
1471 * return
1472 * 0 on success
1473 * error value otherwise
1474 */
1475static int drbg_instantiate(struct drbg_state *drbg, struct drbg_string *pers,
1476                int coreref, bool pr)
1477{
1478    int ret = -ENOMEM;
1479
1480    pr_devel("DRBG: Initializing DRBG core %d with prediction resistance "
1481         "%s\n", coreref, pr ? "enabled" : "disabled");
1482    drbg->core = &drbg_cores[coreref];
1483    drbg->pr = pr;
1484    drbg->seeded = false;
1485    switch (drbg->core->flags & DRBG_TYPE_MASK) {
1486#ifdef CONFIG_CRYPTO_DRBG_HMAC
1487    case DRBG_HMAC:
1488        drbg->d_ops = &drbg_hmac_ops;
1489        break;
1490#endif /* CONFIG_CRYPTO_DRBG_HMAC */
1491#ifdef CONFIG_CRYPTO_DRBG_HASH
1492    case DRBG_HASH:
1493        drbg->d_ops = &drbg_hash_ops;
1494        break;
1495#endif /* CONFIG_CRYPTO_DRBG_HASH */
1496#ifdef CONFIG_CRYPTO_DRBG_CTR
1497    case DRBG_CTR:
1498        drbg->d_ops = &drbg_ctr_ops;
1499        break;
1500#endif /* CONFIG_CRYPTO_DRBG_CTR */
1501    default:
1502        return -EOPNOTSUPP;
1503    }
1504
1505    /* 9.1 step 1 is implicit with the selected DRBG type */
1506
1507    /*
1508     * 9.1 step 2 is implicit as caller can select prediction resistance
1509     * and the flag is copied into drbg->flags --
1510     * all DRBG types support prediction resistance
1511     */
1512
1513    /* 9.1 step 4 is implicit in drbg_sec_strength */
1514
1515    ret = drbg_alloc_state(drbg);
1516    if (ret)
1517        return ret;
1518
1519    ret = -EFAULT;
1520    if (drbg->d_ops->crypto_init(drbg))
1521        goto err;
1522    ret = drbg_seed(drbg, pers, false);
1523    drbg->d_ops->crypto_fini(drbg);
1524    if (ret)
1525        goto err;
1526
1527    return 0;
1528
1529err:
1530    drbg_dealloc_state(drbg);
1531    return ret;
1532}
1533
1534/*
1535 * DRBG uninstantiate function as required by SP800-90A - this function
1536 * frees all buffers and the DRBG handle
1537 *
1538 * @drbg DRBG state handle
1539 *
1540 * return
1541 * 0 on success
1542 */
1543static int drbg_uninstantiate(struct drbg_state *drbg)
1544{
1545    spin_lock_bh(&drbg->drbg_lock);
1546    drbg_dealloc_state(drbg);
1547    /* no scrubbing of test_data -- this shall survive an uninstantiate */
1548    spin_unlock_bh(&drbg->drbg_lock);
1549    return 0;
1550}
1551
1552/*
1553 * Helper function for setting the test data in the DRBG
1554 *
1555 * @drbg DRBG state handle
1556 * @test_data test data to sets
1557 */
1558static inline void drbg_set_testdata(struct drbg_state *drbg,
1559                     struct drbg_test_data *test_data)
1560{
1561    if (!test_data || !test_data->testentropy)
1562        return;
1563    spin_lock_bh(&drbg->drbg_lock);
1564    drbg->test_data = test_data;
1565    spin_unlock_bh(&drbg->drbg_lock);
1566}
1567
1568/***************************************************************
1569 * Kernel crypto API cipher invocations requested by DRBG
1570 ***************************************************************/
1571
1572#if defined(CONFIG_CRYPTO_DRBG_HASH) || defined(CONFIG_CRYPTO_DRBG_HMAC)
1573struct sdesc {
1574    struct shash_desc shash;
1575    char ctx[];
1576};
1577
1578static int drbg_init_hash_kernel(struct drbg_state *drbg)
1579{
1580    struct sdesc *sdesc;
1581    struct crypto_shash *tfm;
1582
1583    tfm = crypto_alloc_shash(drbg->core->backend_cra_name, 0, 0);
1584    if (IS_ERR(tfm)) {
1585        pr_info("DRBG: could not allocate digest TFM handle\n");
1586        return PTR_ERR(tfm);
1587    }
1588    BUG_ON(drbg_blocklen(drbg) != crypto_shash_digestsize(tfm));
1589    sdesc = kzalloc(sizeof(struct shash_desc) + crypto_shash_descsize(tfm),
1590            GFP_KERNEL);
1591    if (!sdesc) {
1592        crypto_free_shash(tfm);
1593        return -ENOMEM;
1594    }
1595
1596    sdesc->shash.tfm = tfm;
1597    sdesc->shash.flags = 0;
1598    drbg->priv_data = sdesc;
1599    return 0;
1600}
1601
1602static int drbg_fini_hash_kernel(struct drbg_state *drbg)
1603{
1604    struct sdesc *sdesc = (struct sdesc *)drbg->priv_data;
1605    if (sdesc) {
1606        crypto_free_shash(sdesc->shash.tfm);
1607        kzfree(sdesc);
1608    }
1609    drbg->priv_data = NULL;
1610    return 0;
1611}
1612
1613static int drbg_kcapi_hash(struct drbg_state *drbg, const unsigned char *key,
1614               unsigned char *outval, const struct list_head *in)
1615{
1616    struct sdesc *sdesc = (struct sdesc *)drbg->priv_data;
1617    struct drbg_string *input = NULL;
1618
1619    if (key)
1620        crypto_shash_setkey(sdesc->shash.tfm, key, drbg_statelen(drbg));
1621    crypto_shash_init(&sdesc->shash);
1622    list_for_each_entry(input, in, list)
1623        crypto_shash_update(&sdesc->shash, input->buf, input->len);
1624    return crypto_shash_final(&sdesc->shash, outval);
1625}
1626#endif /* (CONFIG_CRYPTO_DRBG_HASH || CONFIG_CRYPTO_DRBG_HMAC) */
1627
1628#ifdef CONFIG_CRYPTO_DRBG_CTR
1629static int drbg_init_sym_kernel(struct drbg_state *drbg)
1630{
1631    int ret = 0;
1632    struct crypto_blkcipher *tfm;
1633
1634    tfm = crypto_alloc_blkcipher(drbg->core->backend_cra_name, 0, 0);
1635    if (IS_ERR(tfm)) {
1636        pr_info("DRBG: could not allocate cipher TFM handle\n");
1637        return PTR_ERR(tfm);
1638    }
1639    BUG_ON(drbg_blocklen(drbg) != crypto_blkcipher_blocksize(tfm));
1640    drbg->priv_data = tfm;
1641    return ret;
1642}
1643
1644static int drbg_fini_sym_kernel(struct drbg_state *drbg)
1645{
1646    struct crypto_blkcipher *tfm =
1647        (struct crypto_blkcipher *)drbg->priv_data;
1648    if (tfm)
1649        crypto_free_blkcipher(tfm);
1650    drbg->priv_data = NULL;
1651    return 0;
1652}
1653
1654static int drbg_kcapi_sym(struct drbg_state *drbg, const unsigned char *key,
1655              unsigned char *outval, const struct drbg_string *in)
1656{
1657    int ret = 0;
1658    struct scatterlist sg_in, sg_out;
1659    struct blkcipher_desc desc;
1660    struct crypto_blkcipher *tfm =
1661        (struct crypto_blkcipher *)drbg->priv_data;
1662
1663    desc.tfm = tfm;
1664    desc.flags = 0;
1665    crypto_blkcipher_setkey(tfm, key, (drbg_keylen(drbg)));
1666    /* there is only component in *in */
1667    sg_init_one(&sg_in, in->buf, in->len);
1668    sg_init_one(&sg_out, outval, drbg_blocklen(drbg));
1669    ret = crypto_blkcipher_encrypt(&desc, &sg_out, &sg_in, in->len);
1670
1671    return ret;
1672}
1673#endif /* CONFIG_CRYPTO_DRBG_CTR */
1674
1675/***************************************************************
1676 * Kernel crypto API interface to register DRBG
1677 ***************************************************************/
1678
1679/*
1680 * Look up the DRBG flags by given kernel crypto API cra_name
1681 * The code uses the drbg_cores definition to do this
1682 *
1683 * @cra_name kernel crypto API cra_name
1684 * @coreref reference to integer which is filled with the pointer to
1685 * the applicable core
1686 * @pr reference for setting prediction resistance
1687 *
1688 * return: flags
1689 */
1690static inline void drbg_convert_tfm_core(const char *cra_driver_name,
1691                     int *coreref, bool *pr)
1692{
1693    int i = 0;
1694    size_t start = 0;
1695    int len = 0;
1696
1697    *pr = true;
1698    /* disassemble the names */
1699    if (!memcmp(cra_driver_name, "drbg_nopr_", 10)) {
1700        start = 10;
1701        *pr = false;
1702    } else if (!memcmp(cra_driver_name, "drbg_pr_", 8)) {
1703        start = 8;
1704    } else {
1705        return;
1706    }
1707
1708    /* remove the first part */
1709    len = strlen(cra_driver_name) - start;
1710    for (i = 0; ARRAY_SIZE(drbg_cores) > i; i++) {
1711        if (!memcmp(cra_driver_name + start, drbg_cores[i].cra_name,
1712                len)) {
1713            *coreref = i;
1714            return;
1715        }
1716    }
1717}
1718
1719static int drbg_kcapi_init(struct crypto_tfm *tfm)
1720{
1721    struct drbg_state *drbg = crypto_tfm_ctx(tfm);
1722    bool pr = false;
1723    int coreref = 0;
1724
1725    drbg_convert_tfm_core(crypto_tfm_alg_driver_name(tfm), &coreref, &pr);
1726    /*
1727     * when personalization string is needed, the caller must call reset
1728     * and provide the personalization string as seed information
1729     */
1730    return drbg_instantiate(drbg, NULL, coreref, pr);
1731}
1732
1733static void drbg_kcapi_cleanup(struct crypto_tfm *tfm)
1734{
1735    drbg_uninstantiate(crypto_tfm_ctx(tfm));
1736}
1737
1738/*
1739 * Generate random numbers invoked by the kernel crypto API:
1740 * The API of the kernel crypto API is extended as follows:
1741 *
1742 * If dlen is larger than zero, rdata is interpreted as the output buffer
1743 * where random data is to be stored.
1744 *
1745 * If dlen is zero, rdata is interpreted as a pointer to a struct drbg_gen
1746 * which holds the additional information string that is used for the
1747 * DRBG generation process. The output buffer that is to be used to store
1748 * data is also pointed to by struct drbg_gen.
1749 */
1750static int drbg_kcapi_random(struct crypto_rng *tfm, u8 *rdata,
1751                 unsigned int dlen)
1752{
1753    struct drbg_state *drbg = crypto_rng_ctx(tfm);
1754    if (0 < dlen) {
1755        return drbg_generate_long(drbg, rdata, dlen, NULL);
1756    } else {
1757        struct drbg_gen *data = (struct drbg_gen *)rdata;
1758        struct drbg_string addtl;
1759        /* catch NULL pointer */
1760        if (!data)
1761            return 0;
1762        drbg_set_testdata(drbg, data->test_data);
1763        /* linked list variable is now local to allow modification */
1764        drbg_string_fill(&addtl, data->addtl->buf, data->addtl->len);
1765        return drbg_generate_long(drbg, data->outbuf, data->outlen,
1766                      &addtl);
1767    }
1768}
1769
1770/*
1771 * Reset the DRBG invoked by the kernel crypto API
1772 * The reset implies a full re-initialization of the DRBG. Similar to the
1773 * generate function of drbg_kcapi_random, this function extends the
1774 * kernel crypto API interface with struct drbg_gen
1775 */
1776static int drbg_kcapi_reset(struct crypto_rng *tfm, u8 *seed, unsigned int slen)
1777{
1778    struct drbg_state *drbg = crypto_rng_ctx(tfm);
1779    struct crypto_tfm *tfm_base = crypto_rng_tfm(tfm);
1780    bool pr = false;
1781    struct drbg_string seed_string;
1782    int coreref = 0;
1783
1784    drbg_uninstantiate(drbg);
1785    drbg_convert_tfm_core(crypto_tfm_alg_driver_name(tfm_base), &coreref,
1786                  &pr);
1787    if (0 < slen) {
1788        drbg_string_fill(&seed_string, seed, slen);
1789        return drbg_instantiate(drbg, &seed_string, coreref, pr);
1790    } else {
1791        struct drbg_gen *data = (struct drbg_gen *)seed;
1792        /* allow invocation of API call with NULL, 0 */
1793        if (!data)
1794            return drbg_instantiate(drbg, NULL, coreref, pr);
1795        drbg_set_testdata(drbg, data->test_data);
1796        /* linked list variable is now local to allow modification */
1797        drbg_string_fill(&seed_string, data->addtl->buf,
1798                 data->addtl->len);
1799        return drbg_instantiate(drbg, &seed_string, coreref, pr);
1800    }
1801}
1802
1803/***************************************************************
1804 * Kernel module: code to load the module
1805 ***************************************************************/
1806
1807/*
1808 * Tests as defined in 11.3.2 in addition to the cipher tests: testing
1809 * of the error handling.
1810 *
1811 * Note: testing of failing seed source as defined in 11.3.2 is not applicable
1812 * as seed source of get_random_bytes does not fail.
1813 *
1814 * Note 2: There is no sensible way of testing the reseed counter
1815 * enforcement, so skip it.
1816 */
1817static inline int __init drbg_healthcheck_sanity(void)
1818{
1819#ifdef CONFIG_CRYPTO_FIPS
1820    int len = 0;
1821#define OUTBUFLEN 16
1822    unsigned char buf[OUTBUFLEN];
1823    struct drbg_state *drbg = NULL;
1824    int ret = -EFAULT;
1825    int rc = -EFAULT;
1826    bool pr = false;
1827    int coreref = 0;
1828    struct drbg_string addtl;
1829    size_t max_addtllen, max_request_bytes;
1830
1831    /* only perform test in FIPS mode */
1832    if (!fips_enabled)
1833        return 0;
1834
1835#ifdef CONFIG_CRYPTO_DRBG_CTR
1836    drbg_convert_tfm_core("drbg_nopr_ctr_aes128", &coreref, &pr);
1837#elif defined CONFIG_CRYPTO_DRBG_HASH
1838    drbg_convert_tfm_core("drbg_nopr_sha256", &coreref, &pr);
1839#else
1840    drbg_convert_tfm_core("drbg_nopr_hmac_sha256", &coreref, &pr);
1841#endif
1842
1843    drbg = kzalloc(sizeof(struct drbg_state), GFP_KERNEL);
1844    if (!drbg)
1845        return -ENOMEM;
1846
1847    /*
1848     * if the following tests fail, it is likely that there is a buffer
1849     * overflow as buf is much smaller than the requested or provided
1850     * string lengths -- in case the error handling does not succeed
1851     * we may get an OOPS. And we want to get an OOPS as this is a
1852     * grave bug.
1853     */
1854
1855    /* get a valid instance of DRBG for following tests */
1856    ret = drbg_instantiate(drbg, NULL, coreref, pr);
1857    if (ret) {
1858        rc = ret;
1859        goto outbuf;
1860    }
1861    max_addtllen = drbg_max_addtl(drbg);
1862    max_request_bytes = drbg_max_request_bytes(drbg);
1863    drbg_string_fill(&addtl, buf, max_addtllen + 1);
1864    /* overflow addtllen with additonal info string */
1865    len = drbg_generate(drbg, buf, OUTBUFLEN, &addtl);
1866    BUG_ON(0 < len);
1867    /* overflow max_bits */
1868    len = drbg_generate(drbg, buf, (max_request_bytes + 1), NULL);
1869    BUG_ON(0 < len);
1870    drbg_uninstantiate(drbg);
1871
1872    /* overflow max addtllen with personalization string */
1873    ret = drbg_instantiate(drbg, &addtl, coreref, pr);
1874    BUG_ON(0 == ret);
1875    /* all tests passed */
1876    rc = 0;
1877
1878    pr_devel("DRBG: Sanity tests for failure code paths successfully "
1879         "completed\n");
1880
1881    drbg_uninstantiate(drbg);
1882outbuf:
1883    kzfree(drbg);
1884    return rc;
1885#else /* CONFIG_CRYPTO_FIPS */
1886    return 0;
1887#endif /* CONFIG_CRYPTO_FIPS */
1888}
1889
1890static struct crypto_alg drbg_algs[22];
1891
1892/*
1893 * Fill the array drbg_algs used to register the different DRBGs
1894 * with the kernel crypto API. To fill the array, the information
1895 * from drbg_cores[] is used.
1896 */
1897static inline void __init drbg_fill_array(struct crypto_alg *alg,
1898                      const struct drbg_core *core, int pr)
1899{
1900    int pos = 0;
1901    static int priority = 100;
1902
1903    memset(alg, 0, sizeof(struct crypto_alg));
1904    memcpy(alg->cra_name, "stdrng", 6);
1905    if (pr) {
1906        memcpy(alg->cra_driver_name, "drbg_pr_", 8);
1907        pos = 8;
1908    } else {
1909        memcpy(alg->cra_driver_name, "drbg_nopr_", 10);
1910        pos = 10;
1911    }
1912    memcpy(alg->cra_driver_name + pos, core->cra_name,
1913           strlen(core->cra_name));
1914
1915    alg->cra_priority = priority;
1916    priority++;
1917    /*
1918     * If FIPS mode enabled, the selected DRBG shall have the
1919     * highest cra_priority over other stdrng instances to ensure
1920     * it is selected.
1921     */
1922    if (fips_enabled)
1923        alg->cra_priority += 200;
1924
1925    alg->cra_flags = CRYPTO_ALG_TYPE_RNG;
1926    alg->cra_ctxsize = sizeof(struct drbg_state);
1927    alg->cra_type = &crypto_rng_type;
1928    alg->cra_module = THIS_MODULE;
1929    alg->cra_init = drbg_kcapi_init;
1930    alg->cra_exit = drbg_kcapi_cleanup;
1931    alg->cra_u.rng.rng_make_random = drbg_kcapi_random;
1932    alg->cra_u.rng.rng_reset = drbg_kcapi_reset;
1933    alg->cra_u.rng.seedsize = 0;
1934}
1935
1936static int __init drbg_init(void)
1937{
1938    unsigned int i = 0; /* pointer to drbg_algs */
1939    unsigned int j = 0; /* pointer to drbg_cores */
1940    int ret = -EFAULT;
1941
1942    ret = drbg_healthcheck_sanity();
1943    if (ret)
1944        return ret;
1945
1946    if (ARRAY_SIZE(drbg_cores) * 2 > ARRAY_SIZE(drbg_algs)) {
1947        pr_info("DRBG: Cannot register all DRBG types"
1948            "(slots needed: %zu, slots available: %zu)\n",
1949            ARRAY_SIZE(drbg_cores) * 2, ARRAY_SIZE(drbg_algs));
1950        return ret;
1951    }
1952
1953    /*
1954     * each DRBG definition can be used with PR and without PR, thus
1955     * we instantiate each DRBG in drbg_cores[] twice.
1956     *
1957     * As the order of placing them into the drbg_algs array matters
1958     * (the later DRBGs receive a higher cra_priority) we register the
1959     * prediction resistance DRBGs first as the should not be too
1960     * interesting.
1961     */
1962    for (j = 0; ARRAY_SIZE(drbg_cores) > j; j++, i++)
1963        drbg_fill_array(&drbg_algs[i], &drbg_cores[j], 1);
1964    for (j = 0; ARRAY_SIZE(drbg_cores) > j; j++, i++)
1965        drbg_fill_array(&drbg_algs[i], &drbg_cores[j], 0);
1966    return crypto_register_algs(drbg_algs, (ARRAY_SIZE(drbg_cores) * 2));
1967}
1968
1969static void __exit drbg_exit(void)
1970{
1971    crypto_unregister_algs(drbg_algs, (ARRAY_SIZE(drbg_cores) * 2));
1972}
1973
1974module_init(drbg_init);
1975module_exit(drbg_exit);
1976#ifndef CRYPTO_DRBG_HASH_STRING
1977#define CRYPTO_DRBG_HASH_STRING ""
1978#endif
1979#ifndef CRYPTO_DRBG_HMAC_STRING
1980#define CRYPTO_DRBG_HMAC_STRING ""
1981#endif
1982#ifndef CRYPTO_DRBG_CTR_STRING
1983#define CRYPTO_DRBG_CTR_STRING ""
1984#endif
1985MODULE_LICENSE("GPL");
1986MODULE_AUTHOR("Stephan Mueller <smueller@chronox.de>");
1987MODULE_DESCRIPTION("NIST SP800-90A Deterministic Random Bit Generator (DRBG) "
1988           "using following cores: "
1989           CRYPTO_DRBG_HASH_STRING
1990           CRYPTO_DRBG_HMAC_STRING
1991           CRYPTO_DRBG_CTR_STRING);
1992

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