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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright IBM Corp. 2006, 2015
4 * Author(s): Jan Glauber <jan.glauber@de.ibm.com>
5 * Harald Freudenberger <freude@de.ibm.com>
6 * Driver for the s390 pseudo random number generator
7 */
8
9#define KMSG_COMPONENT "prng"
10#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
11
12#include <linux/fs.h>
13#include <linux/fips.h>
14#include <linux/init.h>
15#include <linux/kernel.h>
16#include <linux/device.h>
17#include <linux/miscdevice.h>
18#include <linux/module.h>
19#include <linux/moduleparam.h>
20#include <linux/mutex.h>
21#include <linux/cpufeature.h>
22#include <linux/random.h>
23#include <linux/slab.h>
24#include <linux/sched/signal.h>
25
26#include <asm/debug.h>
27#include <linux/uaccess.h>
28#include <asm/timex.h>
29#include <asm/cpacf.h>
30
31MODULE_LICENSE("GPL");
32MODULE_AUTHOR("IBM Corporation");
33MODULE_DESCRIPTION("s390 PRNG interface");
34
35
36#define PRNG_MODE_AUTO 0
37#define PRNG_MODE_TDES 1
38#define PRNG_MODE_SHA512 2
39
40static unsigned int prng_mode = PRNG_MODE_AUTO;
41module_param_named(mode, prng_mode, int, 0);
42MODULE_PARM_DESC(prng_mode, "PRNG mode: 0 - auto, 1 - TDES, 2 - SHA512");
43
44
45#define PRNG_CHUNKSIZE_TDES_MIN 8
46#define PRNG_CHUNKSIZE_TDES_MAX (64*1024)
47#define PRNG_CHUNKSIZE_SHA512_MIN 64
48#define PRNG_CHUNKSIZE_SHA512_MAX (64*1024)
49
50static unsigned int prng_chunk_size = 256;
51module_param_named(chunksize, prng_chunk_size, int, 0);
52MODULE_PARM_DESC(prng_chunk_size, "PRNG read chunk size in bytes");
53
54
55#define PRNG_RESEED_LIMIT_TDES 4096
56#define PRNG_RESEED_LIMIT_TDES_LOWER 4096
57#define PRNG_RESEED_LIMIT_SHA512 100000
58#define PRNG_RESEED_LIMIT_SHA512_LOWER 10000
59
60static unsigned int prng_reseed_limit;
61module_param_named(reseed_limit, prng_reseed_limit, int, 0);
62MODULE_PARM_DESC(prng_reseed_limit, "PRNG reseed limit");
63
64static bool trng_available;
65
66/*
67 * Any one who considers arithmetical methods of producing random digits is,
68 * of course, in a state of sin. -- John von Neumann
69 */
70
71static int prng_errorflag;
72
73#define PRNG_GEN_ENTROPY_FAILED 1
74#define PRNG_SELFTEST_FAILED 2
75#define PRNG_INSTANTIATE_FAILED 3
76#define PRNG_SEED_FAILED 4
77#define PRNG_RESEED_FAILED 5
78#define PRNG_GEN_FAILED 6
79
80struct prng_ws_s {
81 u8 parm_block[32];
82 u32 reseed_counter;
83 u64 byte_counter;
84};
85
86struct prno_ws_s {
87 u32 res;
88 u32 reseed_counter;
89 u64 stream_bytes;
90 u8 V[112];
91 u8 C[112];
92};
93
94struct prng_data_s {
95 struct mutex mutex;
96 union {
97 struct prng_ws_s prngws;
98 struct prno_ws_s prnows;
99 };
100 u8 *buf;
101 u32 rest;
102 u8 *prev;
103};
104
105static struct prng_data_s *prng_data;
106
107/* initial parameter block for tdes mode, copied from libica */
108static const u8 initial_parm_block[32] __initconst = {
109 0x0F, 0x2B, 0x8E, 0x63, 0x8C, 0x8E, 0xD2, 0x52,
110 0x64, 0xB7, 0xA0, 0x7B, 0x75, 0x28, 0xB8, 0xF4,
111 0x75, 0x5F, 0xD2, 0xA6, 0x8D, 0x97, 0x11, 0xFF,
112 0x49, 0xD8, 0x23, 0xF3, 0x7E, 0x21, 0xEC, 0xA0 };
113
114
115/*** helper functions ***/
116
117/*
118 * generate_entropy:
119 * This function fills a given buffer with random bytes. The entropy within
120 * the random bytes given back is assumed to have at least 50% - meaning
121 * a 64 bytes buffer has at least 64 * 8 / 2 = 256 bits of entropy.
122 * Within the function the entropy generation is done in junks of 64 bytes.
123 * So the caller should also ask for buffer fill in multiples of 64 bytes.
124 * The generation of the entropy is based on the assumption that every stckf()
125 * invocation produces 0.5 bits of entropy. To accumulate 256 bits of entropy
126 * at least 512 stckf() values are needed. The entropy relevant part of the
127 * stckf value is bit 51 (counting starts at the left with bit nr 0) so
128 * here we use the lower 4 bytes and exor the values into 2k of bufferspace.
129 * To be on the save side, if there is ever a problem with stckf() the
130 * other half of the page buffer is filled with bytes from urandom via
131 * get_random_bytes(), so this function consumes 2k of urandom for each
132 * requested 64 bytes output data. Finally the buffer page is condensed into
133 * a 64 byte value by hashing with a SHA512 hash.
134 */
135static int generate_entropy(u8 *ebuf, size_t nbytes)
136{
137 int n, ret = 0;
138 u8 *pg, pblock[80] = {
139 /* 8 x 64 bit init values */
140 0x6A, 0x09, 0xE6, 0x67, 0xF3, 0xBC, 0xC9, 0x08,
141 0xBB, 0x67, 0xAE, 0x85, 0x84, 0xCA, 0xA7, 0x3B,
142 0x3C, 0x6E, 0xF3, 0x72, 0xFE, 0x94, 0xF8, 0x2B,
143 0xA5, 0x4F, 0xF5, 0x3A, 0x5F, 0x1D, 0x36, 0xF1,
144 0x51, 0x0E, 0x52, 0x7F, 0xAD, 0xE6, 0x82, 0xD1,
145 0x9B, 0x05, 0x68, 0x8C, 0x2B, 0x3E, 0x6C, 0x1F,
146 0x1F, 0x83, 0xD9, 0xAB, 0xFB, 0x41, 0xBD, 0x6B,
147 0x5B, 0xE0, 0xCD, 0x19, 0x13, 0x7E, 0x21, 0x79,
148 /* 128 bit counter total message bit length */
149 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
150 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x80, 0x00 };
151
152 /* allocate one page stckf buffer */
153 pg = (u8 *) __get_free_page(GFP_KERNEL);
154 if (!pg) {
155 prng_errorflag = PRNG_GEN_ENTROPY_FAILED;
156 return -ENOMEM;
157 }
158
159 /* fill the ebuf in chunks of 64 byte each */
160 while (nbytes) {
161 /* fill lower 2k with urandom bytes */
162 get_random_bytes(pg, PAGE_SIZE / 2);
163 /* exor upper 2k with 512 stckf values, offset 4 bytes each */
164 for (n = 0; n < 512; n++) {
165 int offset = (PAGE_SIZE / 2) + (n * 4) - 4;
166 u64 *p = (u64 *)(pg + offset);
167 *p ^= get_tod_clock_fast();
168 }
169 /* hash over the filled page */
170 cpacf_klmd(CPACF_KLMD_SHA_512, pblock, pg, PAGE_SIZE);
171 n = (nbytes < 64) ? nbytes : 64;
172 memcpy(ebuf, pblock, n);
173 ret += n;
174 ebuf += n;
175 nbytes -= n;
176 }
177
178 memzero_explicit(pblock, sizeof(pblock));
179 memzero_explicit(pg, PAGE_SIZE);
180 free_page((unsigned long)pg);
181 return ret;
182}
183
184
185/*** tdes functions ***/
186
187static void prng_tdes_add_entropy(void)
188{
189 __u64 entropy[4];
190 unsigned int i;
191
192 for (i = 0; i < 16; i++) {
193 cpacf_kmc(CPACF_KMC_PRNG, prng_data->prngws.parm_block,
194 (char *) entropy, (char *) entropy,
195 sizeof(entropy));
196 memcpy(prng_data->prngws.parm_block, entropy, sizeof(entropy));
197 }
198}
199
200
201static void prng_tdes_seed(int nbytes)
202{
203 char buf[16];
204 int i = 0;
205
206 BUG_ON(nbytes > sizeof(buf));
207
208 get_random_bytes(buf, nbytes);
209
210 /* Add the entropy */
211 while (nbytes >= 8) {
212 *((__u64 *)prng_data->prngws.parm_block) ^= *((__u64 *)(buf+i));
213 prng_tdes_add_entropy();
214 i += 8;
215 nbytes -= 8;
216 }
217 prng_tdes_add_entropy();
218 prng_data->prngws.reseed_counter = 0;
219}
220
221
222static int __init prng_tdes_instantiate(void)
223{
224 int datalen;
225
226 pr_debug("prng runs in TDES mode with "
227 "chunksize=%d and reseed_limit=%u\n",
228 prng_chunk_size, prng_reseed_limit);
229
230 /* memory allocation, prng_data struct init, mutex init */
231 datalen = sizeof(struct prng_data_s) + prng_chunk_size;
232 prng_data = kzalloc(datalen, GFP_KERNEL);
233 if (!prng_data) {
234 prng_errorflag = PRNG_INSTANTIATE_FAILED;
235 return -ENOMEM;
236 }
237 mutex_init(&prng_data->mutex);
238 prng_data->buf = ((u8 *)prng_data) + sizeof(struct prng_data_s);
239 memcpy(prng_data->prngws.parm_block, initial_parm_block, 32);
240
241 /* initialize the PRNG, add 128 bits of entropy */
242 prng_tdes_seed(16);
243
244 return 0;
245}
246
247
248static void prng_tdes_deinstantiate(void)
249{
250 pr_debug("The prng module stopped "
251 "after running in triple DES mode\n");
252 kfree_sensitive(prng_data);
253}
254
255
256/*** sha512 functions ***/
257
258static int __init prng_sha512_selftest(void)
259{
260 /* NIST DRBG testvector for Hash Drbg, Sha-512, Count #0 */
261 static const u8 seed[] __initconst = {
262 0x6b, 0x50, 0xa7, 0xd8, 0xf8, 0xa5, 0x5d, 0x7a,
263 0x3d, 0xf8, 0xbb, 0x40, 0xbc, 0xc3, 0xb7, 0x22,
264 0xd8, 0x70, 0x8d, 0xe6, 0x7f, 0xda, 0x01, 0x0b,
265 0x03, 0xc4, 0xc8, 0x4d, 0x72, 0x09, 0x6f, 0x8c,
266 0x3e, 0xc6, 0x49, 0xcc, 0x62, 0x56, 0xd9, 0xfa,
267 0x31, 0xdb, 0x7a, 0x29, 0x04, 0xaa, 0xf0, 0x25 };
268 static const u8 V0[] __initconst = {
269 0x00, 0xad, 0xe3, 0x6f, 0x9a, 0x01, 0xc7, 0x76,
270 0x61, 0x34, 0x35, 0xf5, 0x4e, 0x24, 0x74, 0x22,
271 0x21, 0x9a, 0x29, 0x89, 0xc7, 0x93, 0x2e, 0x60,
272 0x1e, 0xe8, 0x14, 0x24, 0x8d, 0xd5, 0x03, 0xf1,
273 0x65, 0x5d, 0x08, 0x22, 0x72, 0xd5, 0xad, 0x95,
274 0xe1, 0x23, 0x1e, 0x8a, 0xa7, 0x13, 0xd9, 0x2b,
275 0x5e, 0xbc, 0xbb, 0x80, 0xab, 0x8d, 0xe5, 0x79,
276 0xab, 0x5b, 0x47, 0x4e, 0xdd, 0xee, 0x6b, 0x03,
277 0x8f, 0x0f, 0x5c, 0x5e, 0xa9, 0x1a, 0x83, 0xdd,
278 0xd3, 0x88, 0xb2, 0x75, 0x4b, 0xce, 0x83, 0x36,
279 0x57, 0x4b, 0xf1, 0x5c, 0xca, 0x7e, 0x09, 0xc0,
280 0xd3, 0x89, 0xc6, 0xe0, 0xda, 0xc4, 0x81, 0x7e,
281 0x5b, 0xf9, 0xe1, 0x01, 0xc1, 0x92, 0x05, 0xea,
282 0xf5, 0x2f, 0xc6, 0xc6, 0xc7, 0x8f, 0xbc, 0xf4 };
283 static const u8 C0[] __initconst = {
284 0x00, 0xf4, 0xa3, 0xe5, 0xa0, 0x72, 0x63, 0x95,
285 0xc6, 0x4f, 0x48, 0xd0, 0x8b, 0x5b, 0x5f, 0x8e,
286 0x6b, 0x96, 0x1f, 0x16, 0xed, 0xbc, 0x66, 0x94,
287 0x45, 0x31, 0xd7, 0x47, 0x73, 0x22, 0xa5, 0x86,
288 0xce, 0xc0, 0x4c, 0xac, 0x63, 0xb8, 0x39, 0x50,
289 0xbf, 0xe6, 0x59, 0x6c, 0x38, 0x58, 0x99, 0x1f,
290 0x27, 0xa7, 0x9d, 0x71, 0x2a, 0xb3, 0x7b, 0xf9,
291 0xfb, 0x17, 0x86, 0xaa, 0x99, 0x81, 0xaa, 0x43,
292 0xe4, 0x37, 0xd3, 0x1e, 0x6e, 0xe5, 0xe6, 0xee,
293 0xc2, 0xed, 0x95, 0x4f, 0x53, 0x0e, 0x46, 0x8a,
294 0xcc, 0x45, 0xa5, 0xdb, 0x69, 0x0d, 0x81, 0xc9,
295 0x32, 0x92, 0xbc, 0x8f, 0x33, 0xe6, 0xf6, 0x09,
296 0x7c, 0x8e, 0x05, 0x19, 0x0d, 0xf1, 0xb6, 0xcc,
297 0xf3, 0x02, 0x21, 0x90, 0x25, 0xec, 0xed, 0x0e };
298 static const u8 random[] __initconst = {
299 0x95, 0xb7, 0xf1, 0x7e, 0x98, 0x02, 0xd3, 0x57,
300 0x73, 0x92, 0xc6, 0xa9, 0xc0, 0x80, 0x83, 0xb6,
301 0x7d, 0xd1, 0x29, 0x22, 0x65, 0xb5, 0xf4, 0x2d,
302 0x23, 0x7f, 0x1c, 0x55, 0xbb, 0x9b, 0x10, 0xbf,
303 0xcf, 0xd8, 0x2c, 0x77, 0xa3, 0x78, 0xb8, 0x26,
304 0x6a, 0x00, 0x99, 0x14, 0x3b, 0x3c, 0x2d, 0x64,
305 0x61, 0x1e, 0xee, 0xb6, 0x9a, 0xcd, 0xc0, 0x55,
306 0x95, 0x7c, 0x13, 0x9e, 0x8b, 0x19, 0x0c, 0x7a,
307 0x06, 0x95, 0x5f, 0x2c, 0x79, 0x7c, 0x27, 0x78,
308 0xde, 0x94, 0x03, 0x96, 0xa5, 0x01, 0xf4, 0x0e,
309 0x91, 0x39, 0x6a, 0xcf, 0x8d, 0x7e, 0x45, 0xeb,
310 0xdb, 0xb5, 0x3b, 0xbf, 0x8c, 0x97, 0x52, 0x30,
311 0xd2, 0xf0, 0xff, 0x91, 0x06, 0xc7, 0x61, 0x19,
312 0xae, 0x49, 0x8e, 0x7f, 0xbc, 0x03, 0xd9, 0x0f,
313 0x8e, 0x4c, 0x51, 0x62, 0x7a, 0xed, 0x5c, 0x8d,
314 0x42, 0x63, 0xd5, 0xd2, 0xb9, 0x78, 0x87, 0x3a,
315 0x0d, 0xe5, 0x96, 0xee, 0x6d, 0xc7, 0xf7, 0xc2,
316 0x9e, 0x37, 0xee, 0xe8, 0xb3, 0x4c, 0x90, 0xdd,
317 0x1c, 0xf6, 0xa9, 0xdd, 0xb2, 0x2b, 0x4c, 0xbd,
318 0x08, 0x6b, 0x14, 0xb3, 0x5d, 0xe9, 0x3d, 0xa2,
319 0xd5, 0xcb, 0x18, 0x06, 0x69, 0x8c, 0xbd, 0x7b,
320 0xbb, 0x67, 0xbf, 0xe3, 0xd3, 0x1f, 0xd2, 0xd1,
321 0xdb, 0xd2, 0xa1, 0xe0, 0x58, 0xa3, 0xeb, 0x99,
322 0xd7, 0xe5, 0x1f, 0x1a, 0x93, 0x8e, 0xed, 0x5e,
323 0x1c, 0x1d, 0xe2, 0x3a, 0x6b, 0x43, 0x45, 0xd3,
324 0x19, 0x14, 0x09, 0xf9, 0x2f, 0x39, 0xb3, 0x67,
325 0x0d, 0x8d, 0xbf, 0xb6, 0x35, 0xd8, 0xe6, 0xa3,
326 0x69, 0x32, 0xd8, 0x10, 0x33, 0xd1, 0x44, 0x8d,
327 0x63, 0xb4, 0x03, 0xdd, 0xf8, 0x8e, 0x12, 0x1b,
328 0x6e, 0x81, 0x9a, 0xc3, 0x81, 0x22, 0x6c, 0x13,
329 0x21, 0xe4, 0xb0, 0x86, 0x44, 0xf6, 0x72, 0x7c,
330 0x36, 0x8c, 0x5a, 0x9f, 0x7a, 0x4b, 0x3e, 0xe2 };
331
332 u8 buf[sizeof(random)];
333 struct prno_ws_s ws;
334
335 memset(&ws, 0, sizeof(ws));
336
337 /* initial seed */
338 cpacf_prno(CPACF_PRNO_SHA512_DRNG_SEED,
339 &ws, NULL, 0, seed, sizeof(seed));
340
341 /* check working states V and C */
342 if (memcmp(ws.V, V0, sizeof(V0)) != 0
343 || memcmp(ws.C, C0, sizeof(C0)) != 0) {
344 pr_err("The prng self test state test "
345 "for the SHA-512 mode failed\n");
346 prng_errorflag = PRNG_SELFTEST_FAILED;
347 return -EIO;
348 }
349
350 /* generate random bytes */
351 cpacf_prno(CPACF_PRNO_SHA512_DRNG_GEN,
352 &ws, buf, sizeof(buf), NULL, 0);
353 cpacf_prno(CPACF_PRNO_SHA512_DRNG_GEN,
354 &ws, buf, sizeof(buf), NULL, 0);
355
356 /* check against expected data */
357 if (memcmp(buf, random, sizeof(random)) != 0) {
358 pr_err("The prng self test data test "
359 "for the SHA-512 mode failed\n");
360 prng_errorflag = PRNG_SELFTEST_FAILED;
361 return -EIO;
362 }
363
364 return 0;
365}
366
367
368static int __init prng_sha512_instantiate(void)
369{
370 int ret, datalen, seedlen;
371 u8 seed[128 + 16];
372
373 pr_debug("prng runs in SHA-512 mode "
374 "with chunksize=%d and reseed_limit=%u\n",
375 prng_chunk_size, prng_reseed_limit);
376
377 /* memory allocation, prng_data struct init, mutex init */
378 datalen = sizeof(struct prng_data_s) + prng_chunk_size;
379 if (fips_enabled)
380 datalen += prng_chunk_size;
381 prng_data = kzalloc(datalen, GFP_KERNEL);
382 if (!prng_data) {
383 prng_errorflag = PRNG_INSTANTIATE_FAILED;
384 return -ENOMEM;
385 }
386 mutex_init(&prng_data->mutex);
387 prng_data->buf = ((u8 *)prng_data) + sizeof(struct prng_data_s);
388
389 /* selftest */
390 ret = prng_sha512_selftest();
391 if (ret)
392 goto outfree;
393
394 /* generate initial seed, we need at least 256 + 128 bits entropy. */
395 if (trng_available) {
396 /*
397 * Trng available, so use it. The trng works in chunks of
398 * 32 bytes and produces 100% entropy. So we pull 64 bytes
399 * which gives us 512 bits entropy.
400 */
401 seedlen = 2 * 32;
402 cpacf_trng(NULL, 0, seed, seedlen);
403 } else {
404 /*
405 * No trng available, so use the generate_entropy() function.
406 * This function works in 64 byte junks and produces
407 * 50% entropy. So we pull 2*64 bytes which gives us 512 bits
408 * of entropy.
409 */
410 seedlen = 2 * 64;
411 ret = generate_entropy(seed, seedlen);
412 if (ret != seedlen)
413 goto outfree;
414 }
415
416 /* append the seed by 16 bytes of unique nonce */
417 store_tod_clock_ext((union tod_clock *)(seed + seedlen));
418 seedlen += 16;
419
420 /* now initial seed of the prno drng */
421 cpacf_prno(CPACF_PRNO_SHA512_DRNG_SEED,
422 &prng_data->prnows, NULL, 0, seed, seedlen);
423 memzero_explicit(seed, sizeof(seed));
424
425 /* if fips mode is enabled, generate a first block of random
426 bytes for the FIPS 140-2 Conditional Self Test */
427 if (fips_enabled) {
428 prng_data->prev = prng_data->buf + prng_chunk_size;
429 cpacf_prno(CPACF_PRNO_SHA512_DRNG_GEN,
430 &prng_data->prnows,
431 prng_data->prev, prng_chunk_size, NULL, 0);
432 }
433
434 return 0;
435
436outfree:
437 kfree(prng_data);
438 return ret;
439}
440
441
442static void prng_sha512_deinstantiate(void)
443{
444 pr_debug("The prng module stopped after running in SHA-512 mode\n");
445 kfree_sensitive(prng_data);
446}
447
448
449static int prng_sha512_reseed(void)
450{
451 int ret, seedlen;
452 u8 seed[64];
453
454 /* We need at least 256 bits of fresh entropy for reseeding */
455 if (trng_available) {
456 /* trng produces 256 bits entropy in 32 bytes */
457 seedlen = 32;
458 cpacf_trng(NULL, 0, seed, seedlen);
459 } else {
460 /* generate_entropy() produces 256 bits entropy in 64 bytes */
461 seedlen = 64;
462 ret = generate_entropy(seed, seedlen);
463 if (ret != sizeof(seed))
464 return ret;
465 }
466
467 /* do a reseed of the prno drng with this bytestring */
468 cpacf_prno(CPACF_PRNO_SHA512_DRNG_SEED,
469 &prng_data->prnows, NULL, 0, seed, seedlen);
470 memzero_explicit(seed, sizeof(seed));
471
472 return 0;
473}
474
475
476static int prng_sha512_generate(u8 *buf, size_t nbytes)
477{
478 int ret;
479
480 /* reseed needed ? */
481 if (prng_data->prnows.reseed_counter > prng_reseed_limit) {
482 ret = prng_sha512_reseed();
483 if (ret)
484 return ret;
485 }
486
487 /* PRNO generate */
488 cpacf_prno(CPACF_PRNO_SHA512_DRNG_GEN,
489 &prng_data->prnows, buf, nbytes, NULL, 0);
490
491 /* FIPS 140-2 Conditional Self Test */
492 if (fips_enabled) {
493 if (!memcmp(prng_data->prev, buf, nbytes)) {
494 prng_errorflag = PRNG_GEN_FAILED;
495 return -EILSEQ;
496 }
497 memcpy(prng_data->prev, buf, nbytes);
498 }
499
500 return nbytes;
501}
502
503
504/*** file io functions ***/
505
506static int prng_open(struct inode *inode, struct file *file)
507{
508 return nonseekable_open(inode, file);
509}
510
511
512static ssize_t prng_tdes_read(struct file *file, char __user *ubuf,
513 size_t nbytes, loff_t *ppos)
514{
515 int chunk, n, ret = 0;
516
517 /* lock prng_data struct */
518 if (mutex_lock_interruptible(&prng_data->mutex))
519 return -ERESTARTSYS;
520
521 while (nbytes) {
522 if (need_resched()) {
523 if (signal_pending(current)) {
524 if (ret == 0)
525 ret = -ERESTARTSYS;
526 break;
527 }
528 /* give mutex free before calling schedule() */
529 mutex_unlock(&prng_data->mutex);
530 schedule();
531 /* occupy mutex again */
532 if (mutex_lock_interruptible(&prng_data->mutex)) {
533 if (ret == 0)
534 ret = -ERESTARTSYS;
535 return ret;
536 }
537 }
538
539 /*
540 * we lose some random bytes if an attacker issues
541 * reads < 8 bytes, but we don't care
542 */
543 chunk = min_t(int, nbytes, prng_chunk_size);
544
545 /* PRNG only likes multiples of 8 bytes */
546 n = (chunk + 7) & -8;
547
548 if (prng_data->prngws.reseed_counter > prng_reseed_limit)
549 prng_tdes_seed(8);
550
551 /* if the CPU supports PRNG stckf is present too */
552 *((unsigned long long *)prng_data->buf) = get_tod_clock_fast();
553
554 /*
555 * Beside the STCKF the input for the TDES-EDE is the output
556 * of the last operation. We differ here from X9.17 since we
557 * only store one timestamp into the buffer. Padding the whole
558 * buffer with timestamps does not improve security, since
559 * successive stckf have nearly constant offsets.
560 * If an attacker knows the first timestamp it would be
561 * trivial to guess the additional values. One timestamp
562 * is therefore enough and still guarantees unique input values.
563 *
564 * Note: you can still get strict X9.17 conformity by setting
565 * prng_chunk_size to 8 bytes.
566 */
567 cpacf_kmc(CPACF_KMC_PRNG, prng_data->prngws.parm_block,
568 prng_data->buf, prng_data->buf, n);
569
570 prng_data->prngws.byte_counter += n;
571 prng_data->prngws.reseed_counter += n;
572
573 if (copy_to_user(ubuf, prng_data->buf, chunk)) {
574 ret = -EFAULT;
575 break;
576 }
577
578 nbytes -= chunk;
579 ret += chunk;
580 ubuf += chunk;
581 }
582
583 /* unlock prng_data struct */
584 mutex_unlock(&prng_data->mutex);
585
586 return ret;
587}
588
589
590static ssize_t prng_sha512_read(struct file *file, char __user *ubuf,
591 size_t nbytes, loff_t *ppos)
592{
593 int n, ret = 0;
594 u8 *p;
595
596 /* if errorflag is set do nothing and return 'broken pipe' */
597 if (prng_errorflag)
598 return -EPIPE;
599
600 /* lock prng_data struct */
601 if (mutex_lock_interruptible(&prng_data->mutex))
602 return -ERESTARTSYS;
603
604 while (nbytes) {
605 if (need_resched()) {
606 if (signal_pending(current)) {
607 if (ret == 0)
608 ret = -ERESTARTSYS;
609 break;
610 }
611 /* give mutex free before calling schedule() */
612 mutex_unlock(&prng_data->mutex);
613 schedule();
614 /* occopy mutex again */
615 if (mutex_lock_interruptible(&prng_data->mutex)) {
616 if (ret == 0)
617 ret = -ERESTARTSYS;
618 return ret;
619 }
620 }
621 if (prng_data->rest) {
622 /* push left over random bytes from the previous read */
623 p = prng_data->buf + prng_chunk_size - prng_data->rest;
624 n = (nbytes < prng_data->rest) ?
625 nbytes : prng_data->rest;
626 prng_data->rest -= n;
627 } else {
628 /* generate one chunk of random bytes into read buf */
629 p = prng_data->buf;
630 n = prng_sha512_generate(p, prng_chunk_size);
631 if (n < 0) {
632 ret = n;
633 break;
634 }
635 if (nbytes < prng_chunk_size) {
636 n = nbytes;
637 prng_data->rest = prng_chunk_size - n;
638 } else {
639 n = prng_chunk_size;
640 prng_data->rest = 0;
641 }
642 }
643 if (copy_to_user(ubuf, p, n)) {
644 ret = -EFAULT;
645 break;
646 }
647 memzero_explicit(p, n);
648 ubuf += n;
649 nbytes -= n;
650 ret += n;
651 }
652
653 /* unlock prng_data struct */
654 mutex_unlock(&prng_data->mutex);
655
656 return ret;
657}
658
659
660/*** sysfs stuff ***/
661
662static const struct file_operations prng_sha512_fops = {
663 .owner = THIS_MODULE,
664 .open = &prng_open,
665 .release = NULL,
666 .read = &prng_sha512_read,
667 .llseek = noop_llseek,
668};
669static const struct file_operations prng_tdes_fops = {
670 .owner = THIS_MODULE,
671 .open = &prng_open,
672 .release = NULL,
673 .read = &prng_tdes_read,
674 .llseek = noop_llseek,
675};
676
677/* chunksize attribute (ro) */
678static ssize_t prng_chunksize_show(struct device *dev,
679 struct device_attribute *attr,
680 char *buf)
681{
682 return scnprintf(buf, PAGE_SIZE, "%u\n", prng_chunk_size);
683}
684static DEVICE_ATTR(chunksize, 0444, prng_chunksize_show, NULL);
685
686/* counter attribute (ro) */
687static ssize_t prng_counter_show(struct device *dev,
688 struct device_attribute *attr,
689 char *buf)
690{
691 u64 counter;
692
693 if (mutex_lock_interruptible(&prng_data->mutex))
694 return -ERESTARTSYS;
695 if (prng_mode == PRNG_MODE_SHA512)
696 counter = prng_data->prnows.stream_bytes;
697 else
698 counter = prng_data->prngws.byte_counter;
699 mutex_unlock(&prng_data->mutex);
700
701 return scnprintf(buf, PAGE_SIZE, "%llu\n", counter);
702}
703static DEVICE_ATTR(byte_counter, 0444, prng_counter_show, NULL);
704
705/* errorflag attribute (ro) */
706static ssize_t prng_errorflag_show(struct device *dev,
707 struct device_attribute *attr,
708 char *buf)
709{
710 return scnprintf(buf, PAGE_SIZE, "%d\n", prng_errorflag);
711}
712static DEVICE_ATTR(errorflag, 0444, prng_errorflag_show, NULL);
713
714/* mode attribute (ro) */
715static ssize_t prng_mode_show(struct device *dev,
716 struct device_attribute *attr,
717 char *buf)
718{
719 if (prng_mode == PRNG_MODE_TDES)
720 return scnprintf(buf, PAGE_SIZE, "TDES\n");
721 else
722 return scnprintf(buf, PAGE_SIZE, "SHA512\n");
723}
724static DEVICE_ATTR(mode, 0444, prng_mode_show, NULL);
725
726/* reseed attribute (w) */
727static ssize_t prng_reseed_store(struct device *dev,
728 struct device_attribute *attr,
729 const char *buf, size_t count)
730{
731 if (mutex_lock_interruptible(&prng_data->mutex))
732 return -ERESTARTSYS;
733 prng_sha512_reseed();
734 mutex_unlock(&prng_data->mutex);
735
736 return count;
737}
738static DEVICE_ATTR(reseed, 0200, NULL, prng_reseed_store);
739
740/* reseed limit attribute (rw) */
741static ssize_t prng_reseed_limit_show(struct device *dev,
742 struct device_attribute *attr,
743 char *buf)
744{
745 return scnprintf(buf, PAGE_SIZE, "%u\n", prng_reseed_limit);
746}
747static ssize_t prng_reseed_limit_store(struct device *dev,
748 struct device_attribute *attr,
749 const char *buf, size_t count)
750{
751 unsigned limit;
752
753 if (sscanf(buf, "%u\n", &limit) != 1)
754 return -EINVAL;
755
756 if (prng_mode == PRNG_MODE_SHA512) {
757 if (limit < PRNG_RESEED_LIMIT_SHA512_LOWER)
758 return -EINVAL;
759 } else {
760 if (limit < PRNG_RESEED_LIMIT_TDES_LOWER)
761 return -EINVAL;
762 }
763
764 prng_reseed_limit = limit;
765
766 return count;
767}
768static DEVICE_ATTR(reseed_limit, 0644,
769 prng_reseed_limit_show, prng_reseed_limit_store);
770
771/* strength attribute (ro) */
772static ssize_t prng_strength_show(struct device *dev,
773 struct device_attribute *attr,
774 char *buf)
775{
776 return scnprintf(buf, PAGE_SIZE, "256\n");
777}
778static DEVICE_ATTR(strength, 0444, prng_strength_show, NULL);
779
780static struct attribute *prng_sha512_dev_attrs[] = {
781 &dev_attr_errorflag.attr,
782 &dev_attr_chunksize.attr,
783 &dev_attr_byte_counter.attr,
784 &dev_attr_mode.attr,
785 &dev_attr_reseed.attr,
786 &dev_attr_reseed_limit.attr,
787 &dev_attr_strength.attr,
788 NULL
789};
790ATTRIBUTE_GROUPS(prng_sha512_dev);
791
792static struct attribute *prng_tdes_dev_attrs[] = {
793 &dev_attr_chunksize.attr,
794 &dev_attr_byte_counter.attr,
795 &dev_attr_mode.attr,
796 NULL
797};
798ATTRIBUTE_GROUPS(prng_tdes_dev);
799
800static struct miscdevice prng_sha512_dev = {
801 .name = "prandom",
802 .minor = MISC_DYNAMIC_MINOR,
803 .mode = 0644,
804 .fops = &prng_sha512_fops,
805 .groups = prng_sha512_dev_groups,
806};
807
808static struct miscdevice prng_tdes_dev = {
809 .name = "prandom",
810 .minor = MISC_DYNAMIC_MINOR,
811 .mode = 0644,
812 .fops = &prng_tdes_fops,
813 .groups = prng_tdes_dev_groups,
814};
815
816
817/*** module init and exit ***/
818
819static int __init prng_init(void)
820{
821 int ret;
822
823 /* check if the CPU has a PRNG */
824 if (!cpacf_query_func(CPACF_KMC, CPACF_KMC_PRNG))
825 return -ENODEV;
826
827 /* check if TRNG subfunction is available */
828 if (cpacf_query_func(CPACF_PRNO, CPACF_PRNO_TRNG))
829 trng_available = true;
830
831 /* choose prng mode */
832 if (prng_mode != PRNG_MODE_TDES) {
833 /* check for MSA5 support for PRNO operations */
834 if (!cpacf_query_func(CPACF_PRNO, CPACF_PRNO_SHA512_DRNG_GEN)) {
835 if (prng_mode == PRNG_MODE_SHA512) {
836 pr_err("The prng module cannot "
837 "start in SHA-512 mode\n");
838 return -ENODEV;
839 }
840 prng_mode = PRNG_MODE_TDES;
841 } else
842 prng_mode = PRNG_MODE_SHA512;
843 }
844
845 if (prng_mode == PRNG_MODE_SHA512) {
846
847 /* SHA512 mode */
848
849 if (prng_chunk_size < PRNG_CHUNKSIZE_SHA512_MIN
850 || prng_chunk_size > PRNG_CHUNKSIZE_SHA512_MAX)
851 return -EINVAL;
852 prng_chunk_size = (prng_chunk_size + 0x3f) & ~0x3f;
853
854 if (prng_reseed_limit == 0)
855 prng_reseed_limit = PRNG_RESEED_LIMIT_SHA512;
856 else if (prng_reseed_limit < PRNG_RESEED_LIMIT_SHA512_LOWER)
857 return -EINVAL;
858
859 ret = prng_sha512_instantiate();
860 if (ret)
861 goto out;
862
863 ret = misc_register(&prng_sha512_dev);
864 if (ret) {
865 prng_sha512_deinstantiate();
866 goto out;
867 }
868
869 } else {
870
871 /* TDES mode */
872
873 if (prng_chunk_size < PRNG_CHUNKSIZE_TDES_MIN
874 || prng_chunk_size > PRNG_CHUNKSIZE_TDES_MAX)
875 return -EINVAL;
876 prng_chunk_size = (prng_chunk_size + 0x07) & ~0x07;
877
878 if (prng_reseed_limit == 0)
879 prng_reseed_limit = PRNG_RESEED_LIMIT_TDES;
880 else if (prng_reseed_limit < PRNG_RESEED_LIMIT_TDES_LOWER)
881 return -EINVAL;
882
883 ret = prng_tdes_instantiate();
884 if (ret)
885 goto out;
886
887 ret = misc_register(&prng_tdes_dev);
888 if (ret) {
889 prng_tdes_deinstantiate();
890 goto out;
891 }
892 }
893
894out:
895 return ret;
896}
897
898
899static void __exit prng_exit(void)
900{
901 if (prng_mode == PRNG_MODE_SHA512) {
902 misc_deregister(&prng_sha512_dev);
903 prng_sha512_deinstantiate();
904 } else {
905 misc_deregister(&prng_tdes_dev);
906 prng_tdes_deinstantiate();
907 }
908}
909
910module_cpu_feature_match(S390_CPU_FEATURE_MSA, prng_init);
911module_exit(prng_exit);
1/*
2 * Copyright IBM Corp. 2006, 2015
3 * Author(s): Jan Glauber <jan.glauber@de.ibm.com>
4 * Harald Freudenberger <freude@de.ibm.com>
5 * Driver for the s390 pseudo random number generator
6 */
7
8#define KMSG_COMPONENT "prng"
9#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
10
11#include <linux/fs.h>
12#include <linux/fips.h>
13#include <linux/init.h>
14#include <linux/kernel.h>
15#include <linux/device.h>
16#include <linux/miscdevice.h>
17#include <linux/module.h>
18#include <linux/moduleparam.h>
19#include <linux/mutex.h>
20#include <linux/cpufeature.h>
21#include <linux/random.h>
22#include <linux/slab.h>
23#include <asm/debug.h>
24#include <linux/uaccess.h>
25#include <asm/timex.h>
26#include <asm/cpacf.h>
27
28MODULE_LICENSE("GPL");
29MODULE_AUTHOR("IBM Corporation");
30MODULE_DESCRIPTION("s390 PRNG interface");
31
32
33#define PRNG_MODE_AUTO 0
34#define PRNG_MODE_TDES 1
35#define PRNG_MODE_SHA512 2
36
37static unsigned int prng_mode = PRNG_MODE_AUTO;
38module_param_named(mode, prng_mode, int, 0);
39MODULE_PARM_DESC(prng_mode, "PRNG mode: 0 - auto, 1 - TDES, 2 - SHA512");
40
41
42#define PRNG_CHUNKSIZE_TDES_MIN 8
43#define PRNG_CHUNKSIZE_TDES_MAX (64*1024)
44#define PRNG_CHUNKSIZE_SHA512_MIN 64
45#define PRNG_CHUNKSIZE_SHA512_MAX (64*1024)
46
47static unsigned int prng_chunk_size = 256;
48module_param_named(chunksize, prng_chunk_size, int, 0);
49MODULE_PARM_DESC(prng_chunk_size, "PRNG read chunk size in bytes");
50
51
52#define PRNG_RESEED_LIMIT_TDES 4096
53#define PRNG_RESEED_LIMIT_TDES_LOWER 4096
54#define PRNG_RESEED_LIMIT_SHA512 100000
55#define PRNG_RESEED_LIMIT_SHA512_LOWER 10000
56
57static unsigned int prng_reseed_limit;
58module_param_named(reseed_limit, prng_reseed_limit, int, 0);
59MODULE_PARM_DESC(prng_reseed_limit, "PRNG reseed limit");
60
61
62/*
63 * Any one who considers arithmetical methods of producing random digits is,
64 * of course, in a state of sin. -- John von Neumann
65 */
66
67static int prng_errorflag;
68
69#define PRNG_GEN_ENTROPY_FAILED 1
70#define PRNG_SELFTEST_FAILED 2
71#define PRNG_INSTANTIATE_FAILED 3
72#define PRNG_SEED_FAILED 4
73#define PRNG_RESEED_FAILED 5
74#define PRNG_GEN_FAILED 6
75
76struct prng_ws_s {
77 u8 parm_block[32];
78 u32 reseed_counter;
79 u64 byte_counter;
80};
81
82struct ppno_ws_s {
83 u32 res;
84 u32 reseed_counter;
85 u64 stream_bytes;
86 u8 V[112];
87 u8 C[112];
88};
89
90struct prng_data_s {
91 struct mutex mutex;
92 union {
93 struct prng_ws_s prngws;
94 struct ppno_ws_s ppnows;
95 };
96 u8 *buf;
97 u32 rest;
98 u8 *prev;
99};
100
101static struct prng_data_s *prng_data;
102
103/* initial parameter block for tdes mode, copied from libica */
104static const u8 initial_parm_block[32] __initconst = {
105 0x0F, 0x2B, 0x8E, 0x63, 0x8C, 0x8E, 0xD2, 0x52,
106 0x64, 0xB7, 0xA0, 0x7B, 0x75, 0x28, 0xB8, 0xF4,
107 0x75, 0x5F, 0xD2, 0xA6, 0x8D, 0x97, 0x11, 0xFF,
108 0x49, 0xD8, 0x23, 0xF3, 0x7E, 0x21, 0xEC, 0xA0 };
109
110
111/*** helper functions ***/
112
113static int generate_entropy(u8 *ebuf, size_t nbytes)
114{
115 int n, ret = 0;
116 u8 *pg, *h, hash[32];
117
118 pg = (u8 *) __get_free_page(GFP_KERNEL);
119 if (!pg) {
120 prng_errorflag = PRNG_GEN_ENTROPY_FAILED;
121 return -ENOMEM;
122 }
123
124 while (nbytes) {
125 /* fill page with urandom bytes */
126 get_random_bytes(pg, PAGE_SIZE);
127 /* exor page with stckf values */
128 for (n = 0; n < PAGE_SIZE / sizeof(u64); n++) {
129 u64 *p = ((u64 *)pg) + n;
130 *p ^= get_tod_clock_fast();
131 }
132 n = (nbytes < sizeof(hash)) ? nbytes : sizeof(hash);
133 if (n < sizeof(hash))
134 h = hash;
135 else
136 h = ebuf;
137 /* generate sha256 from this page */
138 cpacf_kimd(CPACF_KIMD_SHA_256, h, pg, PAGE_SIZE);
139 if (n < sizeof(hash))
140 memcpy(ebuf, hash, n);
141 ret += n;
142 ebuf += n;
143 nbytes -= n;
144 }
145
146 free_page((unsigned long)pg);
147 return ret;
148}
149
150
151/*** tdes functions ***/
152
153static void prng_tdes_add_entropy(void)
154{
155 __u64 entropy[4];
156 unsigned int i;
157
158 for (i = 0; i < 16; i++) {
159 cpacf_kmc(CPACF_KMC_PRNG, prng_data->prngws.parm_block,
160 (char *) entropy, (char *) entropy,
161 sizeof(entropy));
162 memcpy(prng_data->prngws.parm_block, entropy, sizeof(entropy));
163 }
164}
165
166
167static void prng_tdes_seed(int nbytes)
168{
169 char buf[16];
170 int i = 0;
171
172 BUG_ON(nbytes > sizeof(buf));
173
174 get_random_bytes(buf, nbytes);
175
176 /* Add the entropy */
177 while (nbytes >= 8) {
178 *((__u64 *)prng_data->prngws.parm_block) ^= *((__u64 *)(buf+i));
179 prng_tdes_add_entropy();
180 i += 8;
181 nbytes -= 8;
182 }
183 prng_tdes_add_entropy();
184 prng_data->prngws.reseed_counter = 0;
185}
186
187
188static int __init prng_tdes_instantiate(void)
189{
190 int datalen;
191
192 pr_debug("prng runs in TDES mode with "
193 "chunksize=%d and reseed_limit=%u\n",
194 prng_chunk_size, prng_reseed_limit);
195
196 /* memory allocation, prng_data struct init, mutex init */
197 datalen = sizeof(struct prng_data_s) + prng_chunk_size;
198 prng_data = kzalloc(datalen, GFP_KERNEL);
199 if (!prng_data) {
200 prng_errorflag = PRNG_INSTANTIATE_FAILED;
201 return -ENOMEM;
202 }
203 mutex_init(&prng_data->mutex);
204 prng_data->buf = ((u8 *)prng_data) + sizeof(struct prng_data_s);
205 memcpy(prng_data->prngws.parm_block, initial_parm_block, 32);
206
207 /* initialize the PRNG, add 128 bits of entropy */
208 prng_tdes_seed(16);
209
210 return 0;
211}
212
213
214static void prng_tdes_deinstantiate(void)
215{
216 pr_debug("The prng module stopped "
217 "after running in triple DES mode\n");
218 kzfree(prng_data);
219}
220
221
222/*** sha512 functions ***/
223
224static int __init prng_sha512_selftest(void)
225{
226 /* NIST DRBG testvector for Hash Drbg, Sha-512, Count #0 */
227 static const u8 seed[] __initconst = {
228 0x6b, 0x50, 0xa7, 0xd8, 0xf8, 0xa5, 0x5d, 0x7a,
229 0x3d, 0xf8, 0xbb, 0x40, 0xbc, 0xc3, 0xb7, 0x22,
230 0xd8, 0x70, 0x8d, 0xe6, 0x7f, 0xda, 0x01, 0x0b,
231 0x03, 0xc4, 0xc8, 0x4d, 0x72, 0x09, 0x6f, 0x8c,
232 0x3e, 0xc6, 0x49, 0xcc, 0x62, 0x56, 0xd9, 0xfa,
233 0x31, 0xdb, 0x7a, 0x29, 0x04, 0xaa, 0xf0, 0x25 };
234 static const u8 V0[] __initconst = {
235 0x00, 0xad, 0xe3, 0x6f, 0x9a, 0x01, 0xc7, 0x76,
236 0x61, 0x34, 0x35, 0xf5, 0x4e, 0x24, 0x74, 0x22,
237 0x21, 0x9a, 0x29, 0x89, 0xc7, 0x93, 0x2e, 0x60,
238 0x1e, 0xe8, 0x14, 0x24, 0x8d, 0xd5, 0x03, 0xf1,
239 0x65, 0x5d, 0x08, 0x22, 0x72, 0xd5, 0xad, 0x95,
240 0xe1, 0x23, 0x1e, 0x8a, 0xa7, 0x13, 0xd9, 0x2b,
241 0x5e, 0xbc, 0xbb, 0x80, 0xab, 0x8d, 0xe5, 0x79,
242 0xab, 0x5b, 0x47, 0x4e, 0xdd, 0xee, 0x6b, 0x03,
243 0x8f, 0x0f, 0x5c, 0x5e, 0xa9, 0x1a, 0x83, 0xdd,
244 0xd3, 0x88, 0xb2, 0x75, 0x4b, 0xce, 0x83, 0x36,
245 0x57, 0x4b, 0xf1, 0x5c, 0xca, 0x7e, 0x09, 0xc0,
246 0xd3, 0x89, 0xc6, 0xe0, 0xda, 0xc4, 0x81, 0x7e,
247 0x5b, 0xf9, 0xe1, 0x01, 0xc1, 0x92, 0x05, 0xea,
248 0xf5, 0x2f, 0xc6, 0xc6, 0xc7, 0x8f, 0xbc, 0xf4 };
249 static const u8 C0[] __initconst = {
250 0x00, 0xf4, 0xa3, 0xe5, 0xa0, 0x72, 0x63, 0x95,
251 0xc6, 0x4f, 0x48, 0xd0, 0x8b, 0x5b, 0x5f, 0x8e,
252 0x6b, 0x96, 0x1f, 0x16, 0xed, 0xbc, 0x66, 0x94,
253 0x45, 0x31, 0xd7, 0x47, 0x73, 0x22, 0xa5, 0x86,
254 0xce, 0xc0, 0x4c, 0xac, 0x63, 0xb8, 0x39, 0x50,
255 0xbf, 0xe6, 0x59, 0x6c, 0x38, 0x58, 0x99, 0x1f,
256 0x27, 0xa7, 0x9d, 0x71, 0x2a, 0xb3, 0x7b, 0xf9,
257 0xfb, 0x17, 0x86, 0xaa, 0x99, 0x81, 0xaa, 0x43,
258 0xe4, 0x37, 0xd3, 0x1e, 0x6e, 0xe5, 0xe6, 0xee,
259 0xc2, 0xed, 0x95, 0x4f, 0x53, 0x0e, 0x46, 0x8a,
260 0xcc, 0x45, 0xa5, 0xdb, 0x69, 0x0d, 0x81, 0xc9,
261 0x32, 0x92, 0xbc, 0x8f, 0x33, 0xe6, 0xf6, 0x09,
262 0x7c, 0x8e, 0x05, 0x19, 0x0d, 0xf1, 0xb6, 0xcc,
263 0xf3, 0x02, 0x21, 0x90, 0x25, 0xec, 0xed, 0x0e };
264 static const u8 random[] __initconst = {
265 0x95, 0xb7, 0xf1, 0x7e, 0x98, 0x02, 0xd3, 0x57,
266 0x73, 0x92, 0xc6, 0xa9, 0xc0, 0x80, 0x83, 0xb6,
267 0x7d, 0xd1, 0x29, 0x22, 0x65, 0xb5, 0xf4, 0x2d,
268 0x23, 0x7f, 0x1c, 0x55, 0xbb, 0x9b, 0x10, 0xbf,
269 0xcf, 0xd8, 0x2c, 0x77, 0xa3, 0x78, 0xb8, 0x26,
270 0x6a, 0x00, 0x99, 0x14, 0x3b, 0x3c, 0x2d, 0x64,
271 0x61, 0x1e, 0xee, 0xb6, 0x9a, 0xcd, 0xc0, 0x55,
272 0x95, 0x7c, 0x13, 0x9e, 0x8b, 0x19, 0x0c, 0x7a,
273 0x06, 0x95, 0x5f, 0x2c, 0x79, 0x7c, 0x27, 0x78,
274 0xde, 0x94, 0x03, 0x96, 0xa5, 0x01, 0xf4, 0x0e,
275 0x91, 0x39, 0x6a, 0xcf, 0x8d, 0x7e, 0x45, 0xeb,
276 0xdb, 0xb5, 0x3b, 0xbf, 0x8c, 0x97, 0x52, 0x30,
277 0xd2, 0xf0, 0xff, 0x91, 0x06, 0xc7, 0x61, 0x19,
278 0xae, 0x49, 0x8e, 0x7f, 0xbc, 0x03, 0xd9, 0x0f,
279 0x8e, 0x4c, 0x51, 0x62, 0x7a, 0xed, 0x5c, 0x8d,
280 0x42, 0x63, 0xd5, 0xd2, 0xb9, 0x78, 0x87, 0x3a,
281 0x0d, 0xe5, 0x96, 0xee, 0x6d, 0xc7, 0xf7, 0xc2,
282 0x9e, 0x37, 0xee, 0xe8, 0xb3, 0x4c, 0x90, 0xdd,
283 0x1c, 0xf6, 0xa9, 0xdd, 0xb2, 0x2b, 0x4c, 0xbd,
284 0x08, 0x6b, 0x14, 0xb3, 0x5d, 0xe9, 0x3d, 0xa2,
285 0xd5, 0xcb, 0x18, 0x06, 0x69, 0x8c, 0xbd, 0x7b,
286 0xbb, 0x67, 0xbf, 0xe3, 0xd3, 0x1f, 0xd2, 0xd1,
287 0xdb, 0xd2, 0xa1, 0xe0, 0x58, 0xa3, 0xeb, 0x99,
288 0xd7, 0xe5, 0x1f, 0x1a, 0x93, 0x8e, 0xed, 0x5e,
289 0x1c, 0x1d, 0xe2, 0x3a, 0x6b, 0x43, 0x45, 0xd3,
290 0x19, 0x14, 0x09, 0xf9, 0x2f, 0x39, 0xb3, 0x67,
291 0x0d, 0x8d, 0xbf, 0xb6, 0x35, 0xd8, 0xe6, 0xa3,
292 0x69, 0x32, 0xd8, 0x10, 0x33, 0xd1, 0x44, 0x8d,
293 0x63, 0xb4, 0x03, 0xdd, 0xf8, 0x8e, 0x12, 0x1b,
294 0x6e, 0x81, 0x9a, 0xc3, 0x81, 0x22, 0x6c, 0x13,
295 0x21, 0xe4, 0xb0, 0x86, 0x44, 0xf6, 0x72, 0x7c,
296 0x36, 0x8c, 0x5a, 0x9f, 0x7a, 0x4b, 0x3e, 0xe2 };
297
298 u8 buf[sizeof(random)];
299 struct ppno_ws_s ws;
300
301 memset(&ws, 0, sizeof(ws));
302
303 /* initial seed */
304 cpacf_ppno(CPACF_PPNO_SHA512_DRNG_SEED,
305 &ws, NULL, 0, seed, sizeof(seed));
306
307 /* check working states V and C */
308 if (memcmp(ws.V, V0, sizeof(V0)) != 0
309 || memcmp(ws.C, C0, sizeof(C0)) != 0) {
310 pr_err("The prng self test state test "
311 "for the SHA-512 mode failed\n");
312 prng_errorflag = PRNG_SELFTEST_FAILED;
313 return -EIO;
314 }
315
316 /* generate random bytes */
317 cpacf_ppno(CPACF_PPNO_SHA512_DRNG_GEN,
318 &ws, buf, sizeof(buf), NULL, 0);
319 cpacf_ppno(CPACF_PPNO_SHA512_DRNG_GEN,
320 &ws, buf, sizeof(buf), NULL, 0);
321
322 /* check against expected data */
323 if (memcmp(buf, random, sizeof(random)) != 0) {
324 pr_err("The prng self test data test "
325 "for the SHA-512 mode failed\n");
326 prng_errorflag = PRNG_SELFTEST_FAILED;
327 return -EIO;
328 }
329
330 return 0;
331}
332
333
334static int __init prng_sha512_instantiate(void)
335{
336 int ret, datalen;
337 u8 seed[64];
338
339 pr_debug("prng runs in SHA-512 mode "
340 "with chunksize=%d and reseed_limit=%u\n",
341 prng_chunk_size, prng_reseed_limit);
342
343 /* memory allocation, prng_data struct init, mutex init */
344 datalen = sizeof(struct prng_data_s) + prng_chunk_size;
345 if (fips_enabled)
346 datalen += prng_chunk_size;
347 prng_data = kzalloc(datalen, GFP_KERNEL);
348 if (!prng_data) {
349 prng_errorflag = PRNG_INSTANTIATE_FAILED;
350 return -ENOMEM;
351 }
352 mutex_init(&prng_data->mutex);
353 prng_data->buf = ((u8 *)prng_data) + sizeof(struct prng_data_s);
354
355 /* selftest */
356 ret = prng_sha512_selftest();
357 if (ret)
358 goto outfree;
359
360 /* generate initial seed bytestring, first 48 bytes of entropy */
361 ret = generate_entropy(seed, 48);
362 if (ret != 48)
363 goto outfree;
364 /* followed by 16 bytes of unique nonce */
365 get_tod_clock_ext(seed + 48);
366
367 /* initial seed of the ppno drng */
368 cpacf_ppno(CPACF_PPNO_SHA512_DRNG_SEED,
369 &prng_data->ppnows, NULL, 0, seed, sizeof(seed));
370
371 /* if fips mode is enabled, generate a first block of random
372 bytes for the FIPS 140-2 Conditional Self Test */
373 if (fips_enabled) {
374 prng_data->prev = prng_data->buf + prng_chunk_size;
375 cpacf_ppno(CPACF_PPNO_SHA512_DRNG_GEN,
376 &prng_data->ppnows,
377 prng_data->prev, prng_chunk_size, NULL, 0);
378 }
379
380 return 0;
381
382outfree:
383 kfree(prng_data);
384 return ret;
385}
386
387
388static void prng_sha512_deinstantiate(void)
389{
390 pr_debug("The prng module stopped after running in SHA-512 mode\n");
391 kzfree(prng_data);
392}
393
394
395static int prng_sha512_reseed(void)
396{
397 int ret;
398 u8 seed[32];
399
400 /* generate 32 bytes of fresh entropy */
401 ret = generate_entropy(seed, sizeof(seed));
402 if (ret != sizeof(seed))
403 return ret;
404
405 /* do a reseed of the ppno drng with this bytestring */
406 cpacf_ppno(CPACF_PPNO_SHA512_DRNG_SEED,
407 &prng_data->ppnows, NULL, 0, seed, sizeof(seed));
408
409 return 0;
410}
411
412
413static int prng_sha512_generate(u8 *buf, size_t nbytes)
414{
415 int ret;
416
417 /* reseed needed ? */
418 if (prng_data->ppnows.reseed_counter > prng_reseed_limit) {
419 ret = prng_sha512_reseed();
420 if (ret)
421 return ret;
422 }
423
424 /* PPNO generate */
425 cpacf_ppno(CPACF_PPNO_SHA512_DRNG_GEN,
426 &prng_data->ppnows, buf, nbytes, NULL, 0);
427
428 /* FIPS 140-2 Conditional Self Test */
429 if (fips_enabled) {
430 if (!memcmp(prng_data->prev, buf, nbytes)) {
431 prng_errorflag = PRNG_GEN_FAILED;
432 return -EILSEQ;
433 }
434 memcpy(prng_data->prev, buf, nbytes);
435 }
436
437 return nbytes;
438}
439
440
441/*** file io functions ***/
442
443static int prng_open(struct inode *inode, struct file *file)
444{
445 return nonseekable_open(inode, file);
446}
447
448
449static ssize_t prng_tdes_read(struct file *file, char __user *ubuf,
450 size_t nbytes, loff_t *ppos)
451{
452 int chunk, n, ret = 0;
453
454 /* lock prng_data struct */
455 if (mutex_lock_interruptible(&prng_data->mutex))
456 return -ERESTARTSYS;
457
458 while (nbytes) {
459 if (need_resched()) {
460 if (signal_pending(current)) {
461 if (ret == 0)
462 ret = -ERESTARTSYS;
463 break;
464 }
465 /* give mutex free before calling schedule() */
466 mutex_unlock(&prng_data->mutex);
467 schedule();
468 /* occopy mutex again */
469 if (mutex_lock_interruptible(&prng_data->mutex)) {
470 if (ret == 0)
471 ret = -ERESTARTSYS;
472 return ret;
473 }
474 }
475
476 /*
477 * we lose some random bytes if an attacker issues
478 * reads < 8 bytes, but we don't care
479 */
480 chunk = min_t(int, nbytes, prng_chunk_size);
481
482 /* PRNG only likes multiples of 8 bytes */
483 n = (chunk + 7) & -8;
484
485 if (prng_data->prngws.reseed_counter > prng_reseed_limit)
486 prng_tdes_seed(8);
487
488 /* if the CPU supports PRNG stckf is present too */
489 *((unsigned long long *)prng_data->buf) = get_tod_clock_fast();
490
491 /*
492 * Beside the STCKF the input for the TDES-EDE is the output
493 * of the last operation. We differ here from X9.17 since we
494 * only store one timestamp into the buffer. Padding the whole
495 * buffer with timestamps does not improve security, since
496 * successive stckf have nearly constant offsets.
497 * If an attacker knows the first timestamp it would be
498 * trivial to guess the additional values. One timestamp
499 * is therefore enough and still guarantees unique input values.
500 *
501 * Note: you can still get strict X9.17 conformity by setting
502 * prng_chunk_size to 8 bytes.
503 */
504 cpacf_kmc(CPACF_KMC_PRNG, prng_data->prngws.parm_block,
505 prng_data->buf, prng_data->buf, n);
506
507 prng_data->prngws.byte_counter += n;
508 prng_data->prngws.reseed_counter += n;
509
510 if (copy_to_user(ubuf, prng_data->buf, chunk)) {
511 ret = -EFAULT;
512 break;
513 }
514
515 nbytes -= chunk;
516 ret += chunk;
517 ubuf += chunk;
518 }
519
520 /* unlock prng_data struct */
521 mutex_unlock(&prng_data->mutex);
522
523 return ret;
524}
525
526
527static ssize_t prng_sha512_read(struct file *file, char __user *ubuf,
528 size_t nbytes, loff_t *ppos)
529{
530 int n, ret = 0;
531 u8 *p;
532
533 /* if errorflag is set do nothing and return 'broken pipe' */
534 if (prng_errorflag)
535 return -EPIPE;
536
537 /* lock prng_data struct */
538 if (mutex_lock_interruptible(&prng_data->mutex))
539 return -ERESTARTSYS;
540
541 while (nbytes) {
542 if (need_resched()) {
543 if (signal_pending(current)) {
544 if (ret == 0)
545 ret = -ERESTARTSYS;
546 break;
547 }
548 /* give mutex free before calling schedule() */
549 mutex_unlock(&prng_data->mutex);
550 schedule();
551 /* occopy mutex again */
552 if (mutex_lock_interruptible(&prng_data->mutex)) {
553 if (ret == 0)
554 ret = -ERESTARTSYS;
555 return ret;
556 }
557 }
558 if (prng_data->rest) {
559 /* push left over random bytes from the previous read */
560 p = prng_data->buf + prng_chunk_size - prng_data->rest;
561 n = (nbytes < prng_data->rest) ?
562 nbytes : prng_data->rest;
563 prng_data->rest -= n;
564 } else {
565 /* generate one chunk of random bytes into read buf */
566 p = prng_data->buf;
567 n = prng_sha512_generate(p, prng_chunk_size);
568 if (n < 0) {
569 ret = n;
570 break;
571 }
572 if (nbytes < prng_chunk_size) {
573 n = nbytes;
574 prng_data->rest = prng_chunk_size - n;
575 } else {
576 n = prng_chunk_size;
577 prng_data->rest = 0;
578 }
579 }
580 if (copy_to_user(ubuf, p, n)) {
581 ret = -EFAULT;
582 break;
583 }
584 ubuf += n;
585 nbytes -= n;
586 ret += n;
587 }
588
589 /* unlock prng_data struct */
590 mutex_unlock(&prng_data->mutex);
591
592 return ret;
593}
594
595
596/*** sysfs stuff ***/
597
598static const struct file_operations prng_sha512_fops = {
599 .owner = THIS_MODULE,
600 .open = &prng_open,
601 .release = NULL,
602 .read = &prng_sha512_read,
603 .llseek = noop_llseek,
604};
605static const struct file_operations prng_tdes_fops = {
606 .owner = THIS_MODULE,
607 .open = &prng_open,
608 .release = NULL,
609 .read = &prng_tdes_read,
610 .llseek = noop_llseek,
611};
612
613static struct miscdevice prng_sha512_dev = {
614 .name = "prandom",
615 .minor = MISC_DYNAMIC_MINOR,
616 .mode = 0644,
617 .fops = &prng_sha512_fops,
618};
619static struct miscdevice prng_tdes_dev = {
620 .name = "prandom",
621 .minor = MISC_DYNAMIC_MINOR,
622 .mode = 0644,
623 .fops = &prng_tdes_fops,
624};
625
626
627/* chunksize attribute (ro) */
628static ssize_t prng_chunksize_show(struct device *dev,
629 struct device_attribute *attr,
630 char *buf)
631{
632 return snprintf(buf, PAGE_SIZE, "%u\n", prng_chunk_size);
633}
634static DEVICE_ATTR(chunksize, 0444, prng_chunksize_show, NULL);
635
636/* counter attribute (ro) */
637static ssize_t prng_counter_show(struct device *dev,
638 struct device_attribute *attr,
639 char *buf)
640{
641 u64 counter;
642
643 if (mutex_lock_interruptible(&prng_data->mutex))
644 return -ERESTARTSYS;
645 if (prng_mode == PRNG_MODE_SHA512)
646 counter = prng_data->ppnows.stream_bytes;
647 else
648 counter = prng_data->prngws.byte_counter;
649 mutex_unlock(&prng_data->mutex);
650
651 return snprintf(buf, PAGE_SIZE, "%llu\n", counter);
652}
653static DEVICE_ATTR(byte_counter, 0444, prng_counter_show, NULL);
654
655/* errorflag attribute (ro) */
656static ssize_t prng_errorflag_show(struct device *dev,
657 struct device_attribute *attr,
658 char *buf)
659{
660 return snprintf(buf, PAGE_SIZE, "%d\n", prng_errorflag);
661}
662static DEVICE_ATTR(errorflag, 0444, prng_errorflag_show, NULL);
663
664/* mode attribute (ro) */
665static ssize_t prng_mode_show(struct device *dev,
666 struct device_attribute *attr,
667 char *buf)
668{
669 if (prng_mode == PRNG_MODE_TDES)
670 return snprintf(buf, PAGE_SIZE, "TDES\n");
671 else
672 return snprintf(buf, PAGE_SIZE, "SHA512\n");
673}
674static DEVICE_ATTR(mode, 0444, prng_mode_show, NULL);
675
676/* reseed attribute (w) */
677static ssize_t prng_reseed_store(struct device *dev,
678 struct device_attribute *attr,
679 const char *buf, size_t count)
680{
681 if (mutex_lock_interruptible(&prng_data->mutex))
682 return -ERESTARTSYS;
683 prng_sha512_reseed();
684 mutex_unlock(&prng_data->mutex);
685
686 return count;
687}
688static DEVICE_ATTR(reseed, 0200, NULL, prng_reseed_store);
689
690/* reseed limit attribute (rw) */
691static ssize_t prng_reseed_limit_show(struct device *dev,
692 struct device_attribute *attr,
693 char *buf)
694{
695 return snprintf(buf, PAGE_SIZE, "%u\n", prng_reseed_limit);
696}
697static ssize_t prng_reseed_limit_store(struct device *dev,
698 struct device_attribute *attr,
699 const char *buf, size_t count)
700{
701 unsigned limit;
702
703 if (sscanf(buf, "%u\n", &limit) != 1)
704 return -EINVAL;
705
706 if (prng_mode == PRNG_MODE_SHA512) {
707 if (limit < PRNG_RESEED_LIMIT_SHA512_LOWER)
708 return -EINVAL;
709 } else {
710 if (limit < PRNG_RESEED_LIMIT_TDES_LOWER)
711 return -EINVAL;
712 }
713
714 prng_reseed_limit = limit;
715
716 return count;
717}
718static DEVICE_ATTR(reseed_limit, 0644,
719 prng_reseed_limit_show, prng_reseed_limit_store);
720
721/* strength attribute (ro) */
722static ssize_t prng_strength_show(struct device *dev,
723 struct device_attribute *attr,
724 char *buf)
725{
726 return snprintf(buf, PAGE_SIZE, "256\n");
727}
728static DEVICE_ATTR(strength, 0444, prng_strength_show, NULL);
729
730static struct attribute *prng_sha512_dev_attrs[] = {
731 &dev_attr_errorflag.attr,
732 &dev_attr_chunksize.attr,
733 &dev_attr_byte_counter.attr,
734 &dev_attr_mode.attr,
735 &dev_attr_reseed.attr,
736 &dev_attr_reseed_limit.attr,
737 &dev_attr_strength.attr,
738 NULL
739};
740static struct attribute *prng_tdes_dev_attrs[] = {
741 &dev_attr_chunksize.attr,
742 &dev_attr_byte_counter.attr,
743 &dev_attr_mode.attr,
744 NULL
745};
746
747static struct attribute_group prng_sha512_dev_attr_group = {
748 .attrs = prng_sha512_dev_attrs
749};
750static struct attribute_group prng_tdes_dev_attr_group = {
751 .attrs = prng_tdes_dev_attrs
752};
753
754
755/*** module init and exit ***/
756
757static int __init prng_init(void)
758{
759 int ret;
760
761 /* check if the CPU has a PRNG */
762 if (!cpacf_query_func(CPACF_KMC, CPACF_KMC_PRNG))
763 return -EOPNOTSUPP;
764
765 /* choose prng mode */
766 if (prng_mode != PRNG_MODE_TDES) {
767 /* check for MSA5 support for PPNO operations */
768 if (!cpacf_query_func(CPACF_PPNO, CPACF_PPNO_SHA512_DRNG_GEN)) {
769 if (prng_mode == PRNG_MODE_SHA512) {
770 pr_err("The prng module cannot "
771 "start in SHA-512 mode\n");
772 return -EOPNOTSUPP;
773 }
774 prng_mode = PRNG_MODE_TDES;
775 } else
776 prng_mode = PRNG_MODE_SHA512;
777 }
778
779 if (prng_mode == PRNG_MODE_SHA512) {
780
781 /* SHA512 mode */
782
783 if (prng_chunk_size < PRNG_CHUNKSIZE_SHA512_MIN
784 || prng_chunk_size > PRNG_CHUNKSIZE_SHA512_MAX)
785 return -EINVAL;
786 prng_chunk_size = (prng_chunk_size + 0x3f) & ~0x3f;
787
788 if (prng_reseed_limit == 0)
789 prng_reseed_limit = PRNG_RESEED_LIMIT_SHA512;
790 else if (prng_reseed_limit < PRNG_RESEED_LIMIT_SHA512_LOWER)
791 return -EINVAL;
792
793 ret = prng_sha512_instantiate();
794 if (ret)
795 goto out;
796
797 ret = misc_register(&prng_sha512_dev);
798 if (ret) {
799 prng_sha512_deinstantiate();
800 goto out;
801 }
802 ret = sysfs_create_group(&prng_sha512_dev.this_device->kobj,
803 &prng_sha512_dev_attr_group);
804 if (ret) {
805 misc_deregister(&prng_sha512_dev);
806 prng_sha512_deinstantiate();
807 goto out;
808 }
809
810 } else {
811
812 /* TDES mode */
813
814 if (prng_chunk_size < PRNG_CHUNKSIZE_TDES_MIN
815 || prng_chunk_size > PRNG_CHUNKSIZE_TDES_MAX)
816 return -EINVAL;
817 prng_chunk_size = (prng_chunk_size + 0x07) & ~0x07;
818
819 if (prng_reseed_limit == 0)
820 prng_reseed_limit = PRNG_RESEED_LIMIT_TDES;
821 else if (prng_reseed_limit < PRNG_RESEED_LIMIT_TDES_LOWER)
822 return -EINVAL;
823
824 ret = prng_tdes_instantiate();
825 if (ret)
826 goto out;
827
828 ret = misc_register(&prng_tdes_dev);
829 if (ret) {
830 prng_tdes_deinstantiate();
831 goto out;
832 }
833 ret = sysfs_create_group(&prng_tdes_dev.this_device->kobj,
834 &prng_tdes_dev_attr_group);
835 if (ret) {
836 misc_deregister(&prng_tdes_dev);
837 prng_tdes_deinstantiate();
838 goto out;
839 }
840
841 }
842
843out:
844 return ret;
845}
846
847
848static void __exit prng_exit(void)
849{
850 if (prng_mode == PRNG_MODE_SHA512) {
851 sysfs_remove_group(&prng_sha512_dev.this_device->kobj,
852 &prng_sha512_dev_attr_group);
853 misc_deregister(&prng_sha512_dev);
854 prng_sha512_deinstantiate();
855 } else {
856 sysfs_remove_group(&prng_tdes_dev.this_device->kobj,
857 &prng_tdes_dev_attr_group);
858 misc_deregister(&prng_tdes_dev);
859 prng_tdes_deinstantiate();
860 }
861}
862
863module_cpu_feature_match(MSA, prng_init);
864module_exit(prng_exit);