?  search:
summary | log | graphiclog1 | graphiclog2 | commit | commitdiff | tree | refs | edit | fork
blame | history | raw | HEAD
s390/crypto: unlock on error in prng_tdes_read()
[linux/fpc-iii.git] / arch / s390 / crypto / prng.c
blob683a966b5b1662bf78ff94cc805f2d3c222dbafb
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 <asm/uaccess.h>
25 #include <asm/timex.h>
26
27 #include "crypt_s390.h"
28
29 MODULE_LICENSE("GPL");
30 MODULE_AUTHOR("IBM Corporation");
31 MODULE_DESCRIPTION("s390 PRNG interface");
32
33
34 #define PRNG_MODE_AUTO 0
35 #define PRNG_MODE_TDES 1
36 #define PRNG_MODE_SHA512 2
37
38 static unsigned int prng_mode = PRNG_MODE_AUTO;
39 module_param_named(mode, prng_mode, int, 0);
40 MODULE_PARM_DESC(prng_mode, "PRNG mode: 0 - auto, 1 - TDES, 2 - SHA512");
41
42
43 #define PRNG_CHUNKSIZE_TDES_MIN 8
44 #define PRNG_CHUNKSIZE_TDES_MAX (64*1024)
45 #define PRNG_CHUNKSIZE_SHA512_MIN 64
46 #define PRNG_CHUNKSIZE_SHA512_MAX (64*1024)
47
48 static unsigned int prng_chunk_size = 256;
49 module_param_named(chunksize, prng_chunk_size, int, 0);
50 MODULE_PARM_DESC(prng_chunk_size, "PRNG read chunk size in bytes");
51
52
53 #define PRNG_RESEED_LIMIT_TDES 4096
54 #define PRNG_RESEED_LIMIT_TDES_LOWER 4096
55 #define PRNG_RESEED_LIMIT_SHA512 100000
56 #define PRNG_RESEED_LIMIT_SHA512_LOWER 10000
57
58 static unsigned int prng_reseed_limit;
59 module_param_named(reseed_limit, prng_reseed_limit, int, 0);
60 MODULE_PARM_DESC(prng_reseed_limit, "PRNG reseed limit");
61
62
63 /*
64 * Any one who considers arithmetical methods of producing random digits is,
65 * of course, in a state of sin. -- John von Neumann
66 */
67
68 static int prng_errorflag;
69
70 #define PRNG_GEN_ENTROPY_FAILED 1
71 #define PRNG_SELFTEST_FAILED 2
72 #define PRNG_INSTANTIATE_FAILED 3
73 #define PRNG_SEED_FAILED 4
74 #define PRNG_RESEED_FAILED 5
75 #define PRNG_GEN_FAILED 6
76
77 struct prng_ws_s {
78 u8 parm_block[32];
79 u32 reseed_counter;
80 u64 byte_counter;
81 };
82
83 struct ppno_ws_s {
84 u32 res;
85 u32 reseed_counter;
86 u64 stream_bytes;
87 u8 V[112];
88 u8 C[112];
89 };
90
91 struct prng_data_s {
92 struct mutex mutex;
93 union {
94 struct prng_ws_s prngws;
95 struct ppno_ws_s ppnows;
96 };
97 u8 *buf;
98 u32 rest;
99 u8 *prev;
100 };
101
102 static struct prng_data_s *prng_data;
103
104 /* initial parameter block for tdes mode, copied from libica */
105 static const u8 initial_parm_block[32] __initconst = {
106 0x0F, 0x2B, 0x8E, 0x63, 0x8C, 0x8E, 0xD2, 0x52,
107 0x64, 0xB7, 0xA0, 0x7B, 0x75, 0x28, 0xB8, 0xF4,
108 0x75, 0x5F, 0xD2, 0xA6, 0x8D, 0x97, 0x11, 0xFF,
109 0x49, 0xD8, 0x23, 0xF3, 0x7E, 0x21, 0xEC, 0xA0 };
110
111
112 /*** helper functions ***/
113
114 static int generate_entropy(u8 *ebuf, size_t nbytes)
115 {
116 int n, ret = 0;
117 u8 *pg, *h, hash[32];
118
119 pg = (u8 *) __get_free_page(GFP_KERNEL);
120 if (!pg) {
121 prng_errorflag = PRNG_GEN_ENTROPY_FAILED;
122 return -ENOMEM;
123 }
124
125 while (nbytes) {
126 /* fill page with urandom bytes */
127 get_random_bytes(pg, PAGE_SIZE);
128 /* exor page with stckf values */
129 for (n = 0; n < PAGE_SIZE / sizeof(u64); n++) {
130 u64 *p = ((u64 *)pg) + n;
131 *p ^= get_tod_clock_fast();
132 }
133 n = (nbytes < sizeof(hash)) ? nbytes : sizeof(hash);
134 if (n < sizeof(hash))
135 h = hash;
136 else
137 h = ebuf;
138 /* generate sha256 from this page */
139 if (crypt_s390_kimd(KIMD_SHA_256, h,
140 pg, PAGE_SIZE) != PAGE_SIZE) {
141 prng_errorflag = PRNG_GEN_ENTROPY_FAILED;
142 ret = -EIO;
143 goto out;
144 }
145 if (n < sizeof(hash))
146 memcpy(ebuf, hash, n);
147 ret += n;
148 ebuf += n;
149 nbytes -= n;
150 }
151
152 out:
153 free_page((unsigned long)pg);
154 return ret;
155 }
156
157
158 /*** tdes functions ***/
159
160 static void prng_tdes_add_entropy(void)
161 {
162 __u64 entropy[4];
163 unsigned int i;
164 int ret;
165
166 for (i = 0; i < 16; i++) {
167 ret = crypt_s390_kmc(KMC_PRNG, prng_data->prngws.parm_block,
168 (char *)entropy, (char *)entropy,
169 sizeof(entropy));
170 BUG_ON(ret < 0 || ret != sizeof(entropy));
171 memcpy(prng_data->prngws.parm_block, entropy, sizeof(entropy));
172 }
173 }
174
175
176 static void prng_tdes_seed(int nbytes)
177 {
178 char buf[16];
179 int i = 0;
180
181 BUG_ON(nbytes > sizeof(buf));
182
183 get_random_bytes(buf, nbytes);
184
185 /* Add the entropy */
186 while (nbytes >= 8) {
187 *((__u64 *)prng_data->prngws.parm_block) ^= *((__u64 *)(buf+i));
188 prng_tdes_add_entropy();
189 i += 8;
190 nbytes -= 8;
191 }
192 prng_tdes_add_entropy();
193 prng_data->prngws.reseed_counter = 0;
194 }
195
196
197 static int __init prng_tdes_instantiate(void)
198 {
199 int datalen;
200
201 pr_debug("prng runs in TDES mode with "
202 "chunksize=%d and reseed_limit=%u\n",
203 prng_chunk_size, prng_reseed_limit);
204
205 /* memory allocation, prng_data struct init, mutex init */
206 datalen = sizeof(struct prng_data_s) + prng_chunk_size;
207 prng_data = kzalloc(datalen, GFP_KERNEL);
208 if (!prng_data) {
209 prng_errorflag = PRNG_INSTANTIATE_FAILED;
210 return -ENOMEM;
211 }
212 mutex_init(&prng_data->mutex);
213 prng_data->buf = ((u8 *)prng_data) + sizeof(struct prng_data_s);
214 memcpy(prng_data->prngws.parm_block, initial_parm_block, 32);
215
216 /* initialize the PRNG, add 128 bits of entropy */
217 prng_tdes_seed(16);
218
219 return 0;
220 }
221
222
223 static void prng_tdes_deinstantiate(void)
224 {
225 pr_debug("The prng module stopped "
226 "after running in triple DES mode\n");
227 kzfree(prng_data);
228 }
229
230
231 /*** sha512 functions ***/
232
233 static int __init prng_sha512_selftest(void)
234 {
235 /* NIST DRBG testvector for Hash Drbg, Sha-512, Count #0 */
236 static const u8 seed[] __initconst = {
237 0x6b, 0x50, 0xa7, 0xd8, 0xf8, 0xa5, 0x5d, 0x7a,
238 0x3d, 0xf8, 0xbb, 0x40, 0xbc, 0xc3, 0xb7, 0x22,
239 0xd8, 0x70, 0x8d, 0xe6, 0x7f, 0xda, 0x01, 0x0b,
240 0x03, 0xc4, 0xc8, 0x4d, 0x72, 0x09, 0x6f, 0x8c,
241 0x3e, 0xc6, 0x49, 0xcc, 0x62, 0x56, 0xd9, 0xfa,
242 0x31, 0xdb, 0x7a, 0x29, 0x04, 0xaa, 0xf0, 0x25 };
243 static const u8 V0[] __initconst = {
244 0x00, 0xad, 0xe3, 0x6f, 0x9a, 0x01, 0xc7, 0x76,
245 0x61, 0x34, 0x35, 0xf5, 0x4e, 0x24, 0x74, 0x22,
246 0x21, 0x9a, 0x29, 0x89, 0xc7, 0x93, 0x2e, 0x60,
247 0x1e, 0xe8, 0x14, 0x24, 0x8d, 0xd5, 0x03, 0xf1,
248 0x65, 0x5d, 0x08, 0x22, 0x72, 0xd5, 0xad, 0x95,
249 0xe1, 0x23, 0x1e, 0x8a, 0xa7, 0x13, 0xd9, 0x2b,
250 0x5e, 0xbc, 0xbb, 0x80, 0xab, 0x8d, 0xe5, 0x79,
251 0xab, 0x5b, 0x47, 0x4e, 0xdd, 0xee, 0x6b, 0x03,
252 0x8f, 0x0f, 0x5c, 0x5e, 0xa9, 0x1a, 0x83, 0xdd,
253 0xd3, 0x88, 0xb2, 0x75, 0x4b, 0xce, 0x83, 0x36,
254 0x57, 0x4b, 0xf1, 0x5c, 0xca, 0x7e, 0x09, 0xc0,
255 0xd3, 0x89, 0xc6, 0xe0, 0xda, 0xc4, 0x81, 0x7e,
256 0x5b, 0xf9, 0xe1, 0x01, 0xc1, 0x92, 0x05, 0xea,
257 0xf5, 0x2f, 0xc6, 0xc6, 0xc7, 0x8f, 0xbc, 0xf4 };
258 static const u8 C0[] __initconst = {
259 0x00, 0xf4, 0xa3, 0xe5, 0xa0, 0x72, 0x63, 0x95,
260 0xc6, 0x4f, 0x48, 0xd0, 0x8b, 0x5b, 0x5f, 0x8e,
261 0x6b, 0x96, 0x1f, 0x16, 0xed, 0xbc, 0x66, 0x94,
262 0x45, 0x31, 0xd7, 0x47, 0x73, 0x22, 0xa5, 0x86,
263 0xce, 0xc0, 0x4c, 0xac, 0x63, 0xb8, 0x39, 0x50,
264 0xbf, 0xe6, 0x59, 0x6c, 0x38, 0x58, 0x99, 0x1f,
265 0x27, 0xa7, 0x9d, 0x71, 0x2a, 0xb3, 0x7b, 0xf9,
266 0xfb, 0x17, 0x86, 0xaa, 0x99, 0x81, 0xaa, 0x43,
267 0xe4, 0x37, 0xd3, 0x1e, 0x6e, 0xe5, 0xe6, 0xee,
268 0xc2, 0xed, 0x95, 0x4f, 0x53, 0x0e, 0x46, 0x8a,
269 0xcc, 0x45, 0xa5, 0xdb, 0x69, 0x0d, 0x81, 0xc9,
270 0x32, 0x92, 0xbc, 0x8f, 0x33, 0xe6, 0xf6, 0x09,
271 0x7c, 0x8e, 0x05, 0x19, 0x0d, 0xf1, 0xb6, 0xcc,
272 0xf3, 0x02, 0x21, 0x90, 0x25, 0xec, 0xed, 0x0e };
273 static const u8 random[] __initconst = {
274 0x95, 0xb7, 0xf1, 0x7e, 0x98, 0x02, 0xd3, 0x57,
275 0x73, 0x92, 0xc6, 0xa9, 0xc0, 0x80, 0x83, 0xb6,
276 0x7d, 0xd1, 0x29, 0x22, 0x65, 0xb5, 0xf4, 0x2d,
277 0x23, 0x7f, 0x1c, 0x55, 0xbb, 0x9b, 0x10, 0xbf,
278 0xcf, 0xd8, 0x2c, 0x77, 0xa3, 0x78, 0xb8, 0x26,
279 0x6a, 0x00, 0x99, 0x14, 0x3b, 0x3c, 0x2d, 0x64,
280 0x61, 0x1e, 0xee, 0xb6, 0x9a, 0xcd, 0xc0, 0x55,
281 0x95, 0x7c, 0x13, 0x9e, 0x8b, 0x19, 0x0c, 0x7a,
282 0x06, 0x95, 0x5f, 0x2c, 0x79, 0x7c, 0x27, 0x78,
283 0xde, 0x94, 0x03, 0x96, 0xa5, 0x01, 0xf4, 0x0e,
284 0x91, 0x39, 0x6a, 0xcf, 0x8d, 0x7e, 0x45, 0xeb,
285 0xdb, 0xb5, 0x3b, 0xbf, 0x8c, 0x97, 0x52, 0x30,
286 0xd2, 0xf0, 0xff, 0x91, 0x06, 0xc7, 0x61, 0x19,
287 0xae, 0x49, 0x8e, 0x7f, 0xbc, 0x03, 0xd9, 0x0f,
288 0x8e, 0x4c, 0x51, 0x62, 0x7a, 0xed, 0x5c, 0x8d,
289 0x42, 0x63, 0xd5, 0xd2, 0xb9, 0x78, 0x87, 0x3a,
290 0x0d, 0xe5, 0x96, 0xee, 0x6d, 0xc7, 0xf7, 0xc2,
291 0x9e, 0x37, 0xee, 0xe8, 0xb3, 0x4c, 0x90, 0xdd,
292 0x1c, 0xf6, 0xa9, 0xdd, 0xb2, 0x2b, 0x4c, 0xbd,
293 0x08, 0x6b, 0x14, 0xb3, 0x5d, 0xe9, 0x3d, 0xa2,
294 0xd5, 0xcb, 0x18, 0x06, 0x69, 0x8c, 0xbd, 0x7b,
295 0xbb, 0x67, 0xbf, 0xe3, 0xd3, 0x1f, 0xd2, 0xd1,
296 0xdb, 0xd2, 0xa1, 0xe0, 0x58, 0xa3, 0xeb, 0x99,
297 0xd7, 0xe5, 0x1f, 0x1a, 0x93, 0x8e, 0xed, 0x5e,
298 0x1c, 0x1d, 0xe2, 0x3a, 0x6b, 0x43, 0x45, 0xd3,
299 0x19, 0x14, 0x09, 0xf9, 0x2f, 0x39, 0xb3, 0x67,
300 0x0d, 0x8d, 0xbf, 0xb6, 0x35, 0xd8, 0xe6, 0xa3,
301 0x69, 0x32, 0xd8, 0x10, 0x33, 0xd1, 0x44, 0x8d,
302 0x63, 0xb4, 0x03, 0xdd, 0xf8, 0x8e, 0x12, 0x1b,
303 0x6e, 0x81, 0x9a, 0xc3, 0x81, 0x22, 0x6c, 0x13,
304 0x21, 0xe4, 0xb0, 0x86, 0x44, 0xf6, 0x72, 0x7c,
305 0x36, 0x8c, 0x5a, 0x9f, 0x7a, 0x4b, 0x3e, 0xe2 };
306
307 int ret = 0;
308 u8 buf[sizeof(random)];
309 struct ppno_ws_s ws;
310
311 memset(&ws, 0, sizeof(ws));
312
313 /* initial seed */
314 ret = crypt_s390_ppno(PPNO_SHA512_DRNG_SEED,
315 &ws, NULL, 0,
316 seed, sizeof(seed));
317 if (ret < 0) {
318 pr_err("The prng self test seed operation for the "
319 "SHA-512 mode failed with rc=%d\n", ret);
320 prng_errorflag = PRNG_SELFTEST_FAILED;
321 return -EIO;
322 }
323
324 /* check working states V and C */
325 if (memcmp(ws.V, V0, sizeof(V0)) != 0
326 || memcmp(ws.C, C0, sizeof(C0)) != 0) {
327 pr_err("The prng self test state test "
328 "for the SHA-512 mode failed\n");
329 prng_errorflag = PRNG_SELFTEST_FAILED;
330 return -EIO;
331 }
332
333 /* generate random bytes */
334 ret = crypt_s390_ppno(PPNO_SHA512_DRNG_GEN,
335 &ws, buf, sizeof(buf),
336 NULL, 0);
337 if (ret < 0) {
338 pr_err("The prng self test generate operation for "
339 "the SHA-512 mode failed with rc=%d\n", ret);
340 prng_errorflag = PRNG_SELFTEST_FAILED;
341 return -EIO;
342 }
343 ret = crypt_s390_ppno(PPNO_SHA512_DRNG_GEN,
344 &ws, buf, sizeof(buf),
345 NULL, 0);
346 if (ret < 0) {
347 pr_err("The prng self test generate operation for "
348 "the SHA-512 mode failed with rc=%d\n", ret);
349 prng_errorflag = PRNG_SELFTEST_FAILED;
350 return -EIO;
351 }
352
353 /* check against expected data */
354 if (memcmp(buf, random, sizeof(random)) != 0) {
355 pr_err("The prng self test data test "
356 "for the SHA-512 mode failed\n");
357 prng_errorflag = PRNG_SELFTEST_FAILED;
358 return -EIO;
359 }
360
361 return 0;
362 }
363
364
365 static int __init prng_sha512_instantiate(void)
366 {
367 int ret, datalen;
368 u8 seed[64];
369
370 pr_debug("prng runs in SHA-512 mode "
371 "with chunksize=%d and reseed_limit=%u\n",
372 prng_chunk_size, prng_reseed_limit);
373
374 /* memory allocation, prng_data struct init, mutex init */
375 datalen = sizeof(struct prng_data_s) + prng_chunk_size;
376 if (fips_enabled)
377 datalen += prng_chunk_size;
378 prng_data = kzalloc(datalen, GFP_KERNEL);
379 if (!prng_data) {
380 prng_errorflag = PRNG_INSTANTIATE_FAILED;
381 return -ENOMEM;
382 }
383 mutex_init(&prng_data->mutex);
384 prng_data->buf = ((u8 *)prng_data) + sizeof(struct prng_data_s);
385
386 /* selftest */
387 ret = prng_sha512_selftest();
388 if (ret)
389 goto outfree;
390
391 /* generate initial seed bytestring, first 48 bytes of entropy */
392 ret = generate_entropy(seed, 48);
393 if (ret != 48)
394 goto outfree;
395 /* followed by 16 bytes of unique nonce */
396 get_tod_clock_ext(seed + 48);
397
398 /* initial seed of the ppno drng */
399 ret = crypt_s390_ppno(PPNO_SHA512_DRNG_SEED,
400 &prng_data->ppnows, NULL, 0,
401 seed, sizeof(seed));
402 if (ret < 0) {
403 prng_errorflag = PRNG_SEED_FAILED;
404 ret = -EIO;
405 goto outfree;
406 }
407
408 /* if fips mode is enabled, generate a first block of random
409 bytes for the FIPS 140-2 Conditional Self Test */
410 if (fips_enabled) {
411 prng_data->prev = prng_data->buf + prng_chunk_size;
412 ret = crypt_s390_ppno(PPNO_SHA512_DRNG_GEN,
413 &prng_data->ppnows,
414 prng_data->prev,
415 prng_chunk_size,
416 NULL, 0);
417 if (ret < 0 || ret != prng_chunk_size) {
418 prng_errorflag = PRNG_GEN_FAILED;
419 ret = -EIO;
420 goto outfree;
421 }
422 }
423
424 return 0;
425
426 outfree:
427 kfree(prng_data);
428 return ret;
429 }
430
431
432 static void prng_sha512_deinstantiate(void)
433 {
434 pr_debug("The prng module stopped after running in SHA-512 mode\n");
435 kzfree(prng_data);
436 }
437
438
439 static int prng_sha512_reseed(void)
440 {
441 int ret;
442 u8 seed[32];
443
444 /* generate 32 bytes of fresh entropy */
445 ret = generate_entropy(seed, sizeof(seed));
446 if (ret != sizeof(seed))
447 return ret;
448
449 /* do a reseed of the ppno drng with this bytestring */
450 ret = crypt_s390_ppno(PPNO_SHA512_DRNG_SEED,
451 &prng_data->ppnows, NULL, 0,
452 seed, sizeof(seed));
453 if (ret) {
454 prng_errorflag = PRNG_RESEED_FAILED;
455 return -EIO;
456 }
457
458 return 0;
459 }
460
461
462 static int prng_sha512_generate(u8 *buf, size_t nbytes)
463 {
464 int ret;
465
466 /* reseed needed ? */
467 if (prng_data->ppnows.reseed_counter > prng_reseed_limit) {
468 ret = prng_sha512_reseed();
469 if (ret)
470 return ret;
471 }
472
473 /* PPNO generate */
474 ret = crypt_s390_ppno(PPNO_SHA512_DRNG_GEN,
475 &prng_data->ppnows, buf, nbytes,
476 NULL, 0);
477 if (ret < 0 || ret != nbytes) {
478 prng_errorflag = PRNG_GEN_FAILED;
479 return -EIO;
480 }
481
482 /* FIPS 140-2 Conditional Self Test */
483 if (fips_enabled) {
484 if (!memcmp(prng_data->prev, buf, nbytes)) {
485 prng_errorflag = PRNG_GEN_FAILED;
486 return -EILSEQ;
487 }
488 memcpy(prng_data->prev, buf, nbytes);
489 }
490
491 return ret;
492 }
493
494
495 /*** file io functions ***/
496
497 static int prng_open(struct inode *inode, struct file *file)
498 {
499 return nonseekable_open(inode, file);
500 }
501
502
503 static ssize_t prng_tdes_read(struct file *file, char __user *ubuf,
504 size_t nbytes, loff_t *ppos)
505 {
506 int chunk, n, tmp, ret = 0;
507
508 /* lock prng_data struct */
509 if (mutex_lock_interruptible(&prng_data->mutex))
510 return -ERESTARTSYS;
511
512 while (nbytes) {
513 if (need_resched()) {
514 if (signal_pending(current)) {
515 if (ret == 0)
516 ret = -ERESTARTSYS;
517 break;
518 }
519 /* give mutex free before calling schedule() */
520 mutex_unlock(&prng_data->mutex);
521 schedule();
522 /* occopy mutex again */
523 if (mutex_lock_interruptible(&prng_data->mutex)) {
524 if (ret == 0)
525 ret = -ERESTARTSYS;
526 return ret;
527 }
528 }
529
530 /*
531 * we lose some random bytes if an attacker issues
532 * reads < 8 bytes, but we don't care
533 */
534 chunk = min_t(int, nbytes, prng_chunk_size);
535
536 /* PRNG only likes multiples of 8 bytes */
537 n = (chunk + 7) & -8;
538
539 if (prng_data->prngws.reseed_counter > prng_reseed_limit)
540 prng_tdes_seed(8);
541
542 /* if the CPU supports PRNG stckf is present too */
543 *((unsigned long long *)prng_data->buf) = get_tod_clock_fast();
544
545 /*
546 * Beside the STCKF the input for the TDES-EDE is the output
547 * of the last operation. We differ here from X9.17 since we
548 * only store one timestamp into the buffer. Padding the whole
549 * buffer with timestamps does not improve security, since
550 * successive stckf have nearly constant offsets.
551 * If an attacker knows the first timestamp it would be
552 * trivial to guess the additional values. One timestamp
553 * is therefore enough and still guarantees unique input values.
554 *
555 * Note: you can still get strict X9.17 conformity by setting
556 * prng_chunk_size to 8 bytes.
557 */
558 tmp = crypt_s390_kmc(KMC_PRNG, prng_data->prngws.parm_block,
559 prng_data->buf, prng_data->buf, n);
560 if (tmp < 0 || tmp != n) {
561 ret = -EIO;
562 break;
563 }
564
565 prng_data->prngws.byte_counter += n;
566 prng_data->prngws.reseed_counter += n;
567
568 if (copy_to_user(ubuf, prng_data->buf, chunk)) {
569 ret = -EFAULT;
570 break;
571 }
572
573 nbytes -= chunk;
574 ret += chunk;
575 ubuf += chunk;
576 }
577
578 /* unlock prng_data struct */
579 mutex_unlock(&prng_data->mutex);
580
581 return ret;
582 }
583
584
585 static ssize_t prng_sha512_read(struct file *file, char __user *ubuf,
586 size_t nbytes, loff_t *ppos)
587 {
588 int n, ret = 0;
589 u8 *p;
590
591 /* if errorflag is set do nothing and return 'broken pipe' */
592 if (prng_errorflag)
593 return -EPIPE;
594
595 /* lock prng_data struct */
596 if (mutex_lock_interruptible(&prng_data->mutex))
597 return -ERESTARTSYS;
598
599 while (nbytes) {
600 if (need_resched()) {
601 if (signal_pending(current)) {
602 if (ret == 0)
603 ret = -ERESTARTSYS;
604 break;
605 }
606 /* give mutex free before calling schedule() */
607 mutex_unlock(&prng_data->mutex);
608 schedule();
609 /* occopy mutex again */
610 if (mutex_lock_interruptible(&prng_data->mutex)) {
611 if (ret == 0)
612 ret = -ERESTARTSYS;
613 return ret;
614 }
615 }
616 if (prng_data->rest) {
617 /* push left over random bytes from the previous read */
618 p = prng_data->buf + prng_chunk_size - prng_data->rest;
619 n = (nbytes < prng_data->rest) ?
620 nbytes : prng_data->rest;
621 prng_data->rest -= n;
622 } else {
623 /* generate one chunk of random bytes into read buf */
624 p = prng_data->buf;
625 n = prng_sha512_generate(p, prng_chunk_size);
626 if (n < 0) {
627 ret = n;
628 break;
629 }
630 if (nbytes < prng_chunk_size) {
631 n = nbytes;
632 prng_data->rest = prng_chunk_size - n;
633 } else {
634 n = prng_chunk_size;
635 prng_data->rest = 0;
636 }
637 }
638 if (copy_to_user(ubuf, p, n)) {
639 ret = -EFAULT;
640 break;
641 }
642 ubuf += n;
643 nbytes -= n;
644 ret += n;
645 }
646
647 /* unlock prng_data struct */
648 mutex_unlock(&prng_data->mutex);
649
650 return ret;
651 }
652
653
654 /*** sysfs stuff ***/
655
656 static const struct file_operations prng_sha512_fops = {
657 .owner = THIS_MODULE,
658 .open = &prng_open,
659 .release = NULL,
660 .read = &prng_sha512_read,
661 .llseek = noop_llseek,
662 };
663 static const struct file_operations prng_tdes_fops = {
664 .owner = THIS_MODULE,
665 .open = &prng_open,
666 .release = NULL,
667 .read = &prng_tdes_read,
668 .llseek = noop_llseek,
669 };
670
671 static struct miscdevice prng_sha512_dev = {
672 .name = "prandom",
673 .minor = MISC_DYNAMIC_MINOR,
674 .mode = 0644,
675 .fops = &prng_sha512_fops,
676 };
677 static struct miscdevice prng_tdes_dev = {
678 .name = "prandom",
679 .minor = MISC_DYNAMIC_MINOR,
680 .mode = 0644,
681 .fops = &prng_tdes_fops,
682 };
683
684
685 /* chunksize attribute (ro) */
686 static ssize_t prng_chunksize_show(struct device *dev,
687 struct device_attribute *attr,
688 char *buf)
689 {
690 return snprintf(buf, PAGE_SIZE, "%u\n", prng_chunk_size);
691 }
692 static DEVICE_ATTR(chunksize, 0444, prng_chunksize_show, NULL);
693
694 /* counter attribute (ro) */
695 static ssize_t prng_counter_show(struct device *dev,
696 struct device_attribute *attr,
697 char *buf)
698 {
699 u64 counter;
700
701 if (mutex_lock_interruptible(&prng_data->mutex))
702 return -ERESTARTSYS;
703 if (prng_mode == PRNG_MODE_SHA512)
704 counter = prng_data->ppnows.stream_bytes;
705 else
706 counter = prng_data->prngws.byte_counter;
707 mutex_unlock(&prng_data->mutex);
708
709 return snprintf(buf, PAGE_SIZE, "%llu\n", counter);
710 }
711 static DEVICE_ATTR(byte_counter, 0444, prng_counter_show, NULL);
712
713 /* errorflag attribute (ro) */
714 static ssize_t prng_errorflag_show(struct device *dev,
715 struct device_attribute *attr,
716 char *buf)
717 {
718 return snprintf(buf, PAGE_SIZE, "%d\n", prng_errorflag);
719 }
720 static DEVICE_ATTR(errorflag, 0444, prng_errorflag_show, NULL);
721
722 /* mode attribute (ro) */
723 static ssize_t prng_mode_show(struct device *dev,
724 struct device_attribute *attr,
725 char *buf)
726 {
727 if (prng_mode == PRNG_MODE_TDES)
728 return snprintf(buf, PAGE_SIZE, "TDES\n");
729 else
730 return snprintf(buf, PAGE_SIZE, "SHA512\n");
731 }
732 static DEVICE_ATTR(mode, 0444, prng_mode_show, NULL);
733
734 /* reseed attribute (w) */
735 static ssize_t prng_reseed_store(struct device *dev,
736 struct device_attribute *attr,
737 const char *buf, size_t count)
738 {
739 if (mutex_lock_interruptible(&prng_data->mutex))
740 return -ERESTARTSYS;
741 prng_sha512_reseed();
742 mutex_unlock(&prng_data->mutex);
743
744 return count;
745 }
746 static DEVICE_ATTR(reseed, 0200, NULL, prng_reseed_store);
747
748 /* reseed limit attribute (rw) */
749 static ssize_t prng_reseed_limit_show(struct device *dev,
750 struct device_attribute *attr,
751 char *buf)
752 {
753 return snprintf(buf, PAGE_SIZE, "%u\n", prng_reseed_limit);
754 }
755 static ssize_t prng_reseed_limit_store(struct device *dev,
756 struct device_attribute *attr,
757 const char *buf, size_t count)
758 {
759 unsigned limit;
760
761 if (sscanf(buf, "%u\n", &limit) != 1)
762 return -EINVAL;
763
764 if (prng_mode == PRNG_MODE_SHA512) {
765 if (limit < PRNG_RESEED_LIMIT_SHA512_LOWER)
766 return -EINVAL;
767 } else {
768 if (limit < PRNG_RESEED_LIMIT_TDES_LOWER)
769 return -EINVAL;
770 }
771
772 prng_reseed_limit = limit;
773
774 return count;
775 }
776 static DEVICE_ATTR(reseed_limit, 0644,
777 prng_reseed_limit_show, prng_reseed_limit_store);
778
779 /* strength attribute (ro) */
780 static ssize_t prng_strength_show(struct device *dev,
781 struct device_attribute *attr,
782 char *buf)
783 {
784 return snprintf(buf, PAGE_SIZE, "256\n");
785 }
786 static DEVICE_ATTR(strength, 0444, prng_strength_show, NULL);
787
788 static struct attribute *prng_sha512_dev_attrs[] = {
789 &dev_attr_errorflag.attr,
790 &dev_attr_chunksize.attr,
791 &dev_attr_byte_counter.attr,
792 &dev_attr_mode.attr,
793 &dev_attr_reseed.attr,
794 &dev_attr_reseed_limit.attr,
795 &dev_attr_strength.attr,
796 NULL
797 };
798 static struct attribute *prng_tdes_dev_attrs[] = {
799 &dev_attr_chunksize.attr,
800 &dev_attr_byte_counter.attr,
801 &dev_attr_mode.attr,
802 NULL
803 };
804
805 static struct attribute_group prng_sha512_dev_attr_group = {
806 .attrs = prng_sha512_dev_attrs
807 };
808 static struct attribute_group prng_tdes_dev_attr_group = {
809 .attrs = prng_tdes_dev_attrs
810 };
811
812
813 /*** module init and exit ***/
814
815 static int __init prng_init(void)
816 {
817 int ret;
818
819 /* check if the CPU has a PRNG */
820 if (!crypt_s390_func_available(KMC_PRNG, CRYPT_S390_MSA))
821 return -EOPNOTSUPP;
822
823 /* choose prng mode */
824 if (prng_mode != PRNG_MODE_TDES) {
825 /* check for MSA5 support for PPNO operations */
826 if (!crypt_s390_func_available(PPNO_SHA512_DRNG_GEN,
827 CRYPT_S390_MSA5)) {
828 if (prng_mode == PRNG_MODE_SHA512) {
829 pr_err("The prng module cannot "
830 "start in SHA-512 mode\n");
831 return -EOPNOTSUPP;
832 }
833 prng_mode = PRNG_MODE_TDES;
834 } else
835 prng_mode = PRNG_MODE_SHA512;
836 }
837
838 if (prng_mode == PRNG_MODE_SHA512) {
839
840 /* SHA512 mode */
841
842 if (prng_chunk_size < PRNG_CHUNKSIZE_SHA512_MIN
843 || prng_chunk_size > PRNG_CHUNKSIZE_SHA512_MAX)
844 return -EINVAL;
845 prng_chunk_size = (prng_chunk_size + 0x3f) & ~0x3f;
846
847 if (prng_reseed_limit == 0)
848 prng_reseed_limit = PRNG_RESEED_LIMIT_SHA512;
849 else if (prng_reseed_limit < PRNG_RESEED_LIMIT_SHA512_LOWER)
850 return -EINVAL;
851
852 ret = prng_sha512_instantiate();
853 if (ret)
854 goto out;
855
856 ret = misc_register(&prng_sha512_dev);
857 if (ret) {
858 prng_sha512_deinstantiate();
859 goto out;
860 }
861 ret = sysfs_create_group(&prng_sha512_dev.this_device->kobj,
862 &prng_sha512_dev_attr_group);
863 if (ret) {
864 misc_deregister(&prng_sha512_dev);
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 ret = sysfs_create_group(&prng_tdes_dev.this_device->kobj,
893 &prng_tdes_dev_attr_group);
894 if (ret) {
895 misc_deregister(&prng_tdes_dev);
896 prng_tdes_deinstantiate();
897 goto out;
898 }
899
900 }
901
902 out:
903 return ret;
904 }
905
906
907 static void __exit prng_exit(void)
908 {
909 if (prng_mode == PRNG_MODE_SHA512) {
910 sysfs_remove_group(&prng_sha512_dev.this_device->kobj,
911 &prng_sha512_dev_attr_group);
912 misc_deregister(&prng_sha512_dev);
913 prng_sha512_deinstantiate();
914 } else {
915 sysfs_remove_group(&prng_tdes_dev.this_device->kobj,
916 &prng_tdes_dev_attr_group);
917 misc_deregister(&prng_tdes_dev);
918 prng_tdes_deinstantiate();
919 }
920 }
921
922 module_cpu_feature_match(MSA, prng_init);
923 module_exit(prng_exit);
Linux with added FPC-III support