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 <linux/sched/signal.h> 24 25 #include <asm/debug.h> 26 #include <linux/uaccess.h> 27 #include <asm/timex.h> 28 #include <asm/cpacf.h> 29 30 MODULE_LICENSE("GPL"); 31 MODULE_AUTHOR("IBM Corporation"); 32 MODULE_DESCRIPTION("s390 PRNG interface"); 33 34 35 #define PRNG_MODE_AUTO 0 36 #define PRNG_MODE_TDES 1 37 #define PRNG_MODE_SHA512 2 38 39 static unsigned int prng_mode = PRNG_MODE_AUTO; 40 module_param_named(mode, prng_mode, int, 0); 41 MODULE_PARM_DESC(prng_mode, "PRNG mode: 0 - auto, 1 - TDES, 2 - SHA512"); 42 43 44 #define PRNG_CHUNKSIZE_TDES_MIN 8 45 #define PRNG_CHUNKSIZE_TDES_MAX (64*1024) 46 #define PRNG_CHUNKSIZE_SHA512_MIN 64 47 #define PRNG_CHUNKSIZE_SHA512_MAX (64*1024) 48 49 static unsigned int prng_chunk_size = 256; 50 module_param_named(chunksize, prng_chunk_size, int, 0); 51 MODULE_PARM_DESC(prng_chunk_size, "PRNG read chunk size in bytes"); 52 53 54 #define PRNG_RESEED_LIMIT_TDES 4096 55 #define PRNG_RESEED_LIMIT_TDES_LOWER 4096 56 #define PRNG_RESEED_LIMIT_SHA512 100000 57 #define PRNG_RESEED_LIMIT_SHA512_LOWER 10000 58 59 static unsigned int prng_reseed_limit; 60 module_param_named(reseed_limit, prng_reseed_limit, int, 0); 61 MODULE_PARM_DESC(prng_reseed_limit, "PRNG reseed limit"); 62 63 64 /* 65 * Any one who considers arithmetical methods of producing random digits is, 66 * of course, in a state of sin. -- John von Neumann 67 */ 68 69 static int prng_errorflag; 70 71 #define PRNG_GEN_ENTROPY_FAILED 1 72 #define PRNG_SELFTEST_FAILED 2 73 #define PRNG_INSTANTIATE_FAILED 3 74 #define PRNG_SEED_FAILED 4 75 #define PRNG_RESEED_FAILED 5 76 #define PRNG_GEN_FAILED 6 77 78 struct prng_ws_s { 79 u8 parm_block[32]; 80 u32 reseed_counter; 81 u64 byte_counter; 82 }; 83 84 struct prno_ws_s { 85 u32 res; 86 u32 reseed_counter; 87 u64 stream_bytes; 88 u8 V[112]; 89 u8 C[112]; 90 }; 91 92 struct prng_data_s { 93 struct mutex mutex; 94 union { 95 struct prng_ws_s prngws; 96 struct prno_ws_s prnows; 97 }; 98 u8 *buf; 99 u32 rest; 100 u8 *prev; 101 }; 102 103 static struct prng_data_s *prng_data; 104 105 /* initial parameter block for tdes mode, copied from libica */ 106 static const u8 initial_parm_block[32] __initconst = { 107 0x0F, 0x2B, 0x8E, 0x63, 0x8C, 0x8E, 0xD2, 0x52, 108 0x64, 0xB7, 0xA0, 0x7B, 0x75, 0x28, 0xB8, 0xF4, 109 0x75, 0x5F, 0xD2, 0xA6, 0x8D, 0x97, 0x11, 0xFF, 110 0x49, 0xD8, 0x23, 0xF3, 0x7E, 0x21, 0xEC, 0xA0 }; 111 112 113 /*** helper functions ***/ 114 115 /* 116 * generate_entropy: 117 * This algorithm produces 64 bytes of entropy data based on 1024 118 * individual stckf() invocations assuming that each stckf() value 119 * contributes 0.25 bits of entropy. So the caller gets 256 bit 120 * entropy per 64 byte or 4 bits entropy per byte. 121 */ 122 static int generate_entropy(u8 *ebuf, size_t nbytes) 123 { 124 int n, ret = 0; 125 u8 *pg, *h, hash[64]; 126 127 /* allocate 2 pages */ 128 pg = (u8 *) __get_free_pages(GFP_KERNEL, 1); 129 if (!pg) { 130 prng_errorflag = PRNG_GEN_ENTROPY_FAILED; 131 return -ENOMEM; 132 } 133 134 while (nbytes) { 135 /* fill pages with urandom bytes */ 136 get_random_bytes(pg, 2*PAGE_SIZE); 137 /* exor pages with 1024 stckf values */ 138 for (n = 0; n < 2 * PAGE_SIZE / sizeof(u64); n++) { 139 u64 *p = ((u64 *)pg) + n; 140 *p ^= get_tod_clock_fast(); 141 } 142 n = (nbytes < sizeof(hash)) ? nbytes : sizeof(hash); 143 if (n < sizeof(hash)) 144 h = hash; 145 else 146 h = ebuf; 147 /* hash over the filled pages */ 148 cpacf_kimd(CPACF_KIMD_SHA_512, h, pg, 2*PAGE_SIZE); 149 if (n < sizeof(hash)) 150 memcpy(ebuf, hash, n); 151 ret += n; 152 ebuf += n; 153 nbytes -= n; 154 } 155 156 free_pages((unsigned long)pg, 1); 157 return ret; 158 } 159 160 161 /*** tdes functions ***/ 162 163 static void prng_tdes_add_entropy(void) 164 { 165 __u64 entropy[4]; 166 unsigned int i; 167 168 for (i = 0; i < 16; i++) { 169 cpacf_kmc(CPACF_KMC_PRNG, prng_data->prngws.parm_block, 170 (char *) entropy, (char *) entropy, 171 sizeof(entropy)); 172 memcpy(prng_data->prngws.parm_block, entropy, sizeof(entropy)); 173 } 174 } 175 176 177 static void prng_tdes_seed(int nbytes) 178 { 179 char buf[16]; 180 int i = 0; 181 182 BUG_ON(nbytes > sizeof(buf)); 183 184 get_random_bytes(buf, nbytes); 185 186 /* Add the entropy */ 187 while (nbytes >= 8) { 188 *((__u64 *)prng_data->prngws.parm_block) ^= *((__u64 *)(buf+i)); 189 prng_tdes_add_entropy(); 190 i += 8; 191 nbytes -= 8; 192 } 193 prng_tdes_add_entropy(); 194 prng_data->prngws.reseed_counter = 0; 195 } 196 197 198 static int __init prng_tdes_instantiate(void) 199 { 200 int datalen; 201 202 pr_debug("prng runs in TDES mode with " 203 "chunksize=%d and reseed_limit=%u\n", 204 prng_chunk_size, prng_reseed_limit); 205 206 /* memory allocation, prng_data struct init, mutex init */ 207 datalen = sizeof(struct prng_data_s) + prng_chunk_size; 208 prng_data = kzalloc(datalen, GFP_KERNEL); 209 if (!prng_data) { 210 prng_errorflag = PRNG_INSTANTIATE_FAILED; 211 return -ENOMEM; 212 } 213 mutex_init(&prng_data->mutex); 214 prng_data->buf = ((u8 *)prng_data) + sizeof(struct prng_data_s); 215 memcpy(prng_data->prngws.parm_block, initial_parm_block, 32); 216 217 /* initialize the PRNG, add 128 bits of entropy */ 218 prng_tdes_seed(16); 219 220 return 0; 221 } 222 223 224 static void prng_tdes_deinstantiate(void) 225 { 226 pr_debug("The prng module stopped " 227 "after running in triple DES mode\n"); 228 kzfree(prng_data); 229 } 230 231 232 /*** sha512 functions ***/ 233 234 static int __init prng_sha512_selftest(void) 235 { 236 /* NIST DRBG testvector for Hash Drbg, Sha-512, Count #0 */ 237 static const u8 seed[] __initconst = { 238 0x6b, 0x50, 0xa7, 0xd8, 0xf8, 0xa5, 0x5d, 0x7a, 239 0x3d, 0xf8, 0xbb, 0x40, 0xbc, 0xc3, 0xb7, 0x22, 240 0xd8, 0x70, 0x8d, 0xe6, 0x7f, 0xda, 0x01, 0x0b, 241 0x03, 0xc4, 0xc8, 0x4d, 0x72, 0x09, 0x6f, 0x8c, 242 0x3e, 0xc6, 0x49, 0xcc, 0x62, 0x56, 0xd9, 0xfa, 243 0x31, 0xdb, 0x7a, 0x29, 0x04, 0xaa, 0xf0, 0x25 }; 244 static const u8 V0[] __initconst = { 245 0x00, 0xad, 0xe3, 0x6f, 0x9a, 0x01, 0xc7, 0x76, 246 0x61, 0x34, 0x35, 0xf5, 0x4e, 0x24, 0x74, 0x22, 247 0x21, 0x9a, 0x29, 0x89, 0xc7, 0x93, 0x2e, 0x60, 248 0x1e, 0xe8, 0x14, 0x24, 0x8d, 0xd5, 0x03, 0xf1, 249 0x65, 0x5d, 0x08, 0x22, 0x72, 0xd5, 0xad, 0x95, 250 0xe1, 0x23, 0x1e, 0x8a, 0xa7, 0x13, 0xd9, 0x2b, 251 0x5e, 0xbc, 0xbb, 0x80, 0xab, 0x8d, 0xe5, 0x79, 252 0xab, 0x5b, 0x47, 0x4e, 0xdd, 0xee, 0x6b, 0x03, 253 0x8f, 0x0f, 0x5c, 0x5e, 0xa9, 0x1a, 0x83, 0xdd, 254 0xd3, 0x88, 0xb2, 0x75, 0x4b, 0xce, 0x83, 0x36, 255 0x57, 0x4b, 0xf1, 0x5c, 0xca, 0x7e, 0x09, 0xc0, 256 0xd3, 0x89, 0xc6, 0xe0, 0xda, 0xc4, 0x81, 0x7e, 257 0x5b, 0xf9, 0xe1, 0x01, 0xc1, 0x92, 0x05, 0xea, 258 0xf5, 0x2f, 0xc6, 0xc6, 0xc7, 0x8f, 0xbc, 0xf4 }; 259 static const u8 C0[] __initconst = { 260 0x00, 0xf4, 0xa3, 0xe5, 0xa0, 0x72, 0x63, 0x95, 261 0xc6, 0x4f, 0x48, 0xd0, 0x8b, 0x5b, 0x5f, 0x8e, 262 0x6b, 0x96, 0x1f, 0x16, 0xed, 0xbc, 0x66, 0x94, 263 0x45, 0x31, 0xd7, 0x47, 0x73, 0x22, 0xa5, 0x86, 264 0xce, 0xc0, 0x4c, 0xac, 0x63, 0xb8, 0x39, 0x50, 265 0xbf, 0xe6, 0x59, 0x6c, 0x38, 0x58, 0x99, 0x1f, 266 0x27, 0xa7, 0x9d, 0x71, 0x2a, 0xb3, 0x7b, 0xf9, 267 0xfb, 0x17, 0x86, 0xaa, 0x99, 0x81, 0xaa, 0x43, 268 0xe4, 0x37, 0xd3, 0x1e, 0x6e, 0xe5, 0xe6, 0xee, 269 0xc2, 0xed, 0x95, 0x4f, 0x53, 0x0e, 0x46, 0x8a, 270 0xcc, 0x45, 0xa5, 0xdb, 0x69, 0x0d, 0x81, 0xc9, 271 0x32, 0x92, 0xbc, 0x8f, 0x33, 0xe6, 0xf6, 0x09, 272 0x7c, 0x8e, 0x05, 0x19, 0x0d, 0xf1, 0xb6, 0xcc, 273 0xf3, 0x02, 0x21, 0x90, 0x25, 0xec, 0xed, 0x0e }; 274 static const u8 random[] __initconst = { 275 0x95, 0xb7, 0xf1, 0x7e, 0x98, 0x02, 0xd3, 0x57, 276 0x73, 0x92, 0xc6, 0xa9, 0xc0, 0x80, 0x83, 0xb6, 277 0x7d, 0xd1, 0x29, 0x22, 0x65, 0xb5, 0xf4, 0x2d, 278 0x23, 0x7f, 0x1c, 0x55, 0xbb, 0x9b, 0x10, 0xbf, 279 0xcf, 0xd8, 0x2c, 0x77, 0xa3, 0x78, 0xb8, 0x26, 280 0x6a, 0x00, 0x99, 0x14, 0x3b, 0x3c, 0x2d, 0x64, 281 0x61, 0x1e, 0xee, 0xb6, 0x9a, 0xcd, 0xc0, 0x55, 282 0x95, 0x7c, 0x13, 0x9e, 0x8b, 0x19, 0x0c, 0x7a, 283 0x06, 0x95, 0x5f, 0x2c, 0x79, 0x7c, 0x27, 0x78, 284 0xde, 0x94, 0x03, 0x96, 0xa5, 0x01, 0xf4, 0x0e, 285 0x91, 0x39, 0x6a, 0xcf, 0x8d, 0x7e, 0x45, 0xeb, 286 0xdb, 0xb5, 0x3b, 0xbf, 0x8c, 0x97, 0x52, 0x30, 287 0xd2, 0xf0, 0xff, 0x91, 0x06, 0xc7, 0x61, 0x19, 288 0xae, 0x49, 0x8e, 0x7f, 0xbc, 0x03, 0xd9, 0x0f, 289 0x8e, 0x4c, 0x51, 0x62, 0x7a, 0xed, 0x5c, 0x8d, 290 0x42, 0x63, 0xd5, 0xd2, 0xb9, 0x78, 0x87, 0x3a, 291 0x0d, 0xe5, 0x96, 0xee, 0x6d, 0xc7, 0xf7, 0xc2, 292 0x9e, 0x37, 0xee, 0xe8, 0xb3, 0x4c, 0x90, 0xdd, 293 0x1c, 0xf6, 0xa9, 0xdd, 0xb2, 0x2b, 0x4c, 0xbd, 294 0x08, 0x6b, 0x14, 0xb3, 0x5d, 0xe9, 0x3d, 0xa2, 295 0xd5, 0xcb, 0x18, 0x06, 0x69, 0x8c, 0xbd, 0x7b, 296 0xbb, 0x67, 0xbf, 0xe3, 0xd3, 0x1f, 0xd2, 0xd1, 297 0xdb, 0xd2, 0xa1, 0xe0, 0x58, 0xa3, 0xeb, 0x99, 298 0xd7, 0xe5, 0x1f, 0x1a, 0x93, 0x8e, 0xed, 0x5e, 299 0x1c, 0x1d, 0xe2, 0x3a, 0x6b, 0x43, 0x45, 0xd3, 300 0x19, 0x14, 0x09, 0xf9, 0x2f, 0x39, 0xb3, 0x67, 301 0x0d, 0x8d, 0xbf, 0xb6, 0x35, 0xd8, 0xe6, 0xa3, 302 0x69, 0x32, 0xd8, 0x10, 0x33, 0xd1, 0x44, 0x8d, 303 0x63, 0xb4, 0x03, 0xdd, 0xf8, 0x8e, 0x12, 0x1b, 304 0x6e, 0x81, 0x9a, 0xc3, 0x81, 0x22, 0x6c, 0x13, 305 0x21, 0xe4, 0xb0, 0x86, 0x44, 0xf6, 0x72, 0x7c, 306 0x36, 0x8c, 0x5a, 0x9f, 0x7a, 0x4b, 0x3e, 0xe2 }; 307 308 u8 buf[sizeof(random)]; 309 struct prno_ws_s ws; 310 311 memset(&ws, 0, sizeof(ws)); 312 313 /* initial seed */ 314 cpacf_prno(CPACF_PRNO_SHA512_DRNG_SEED, 315 &ws, NULL, 0, seed, sizeof(seed)); 316 317 /* check working states V and C */ 318 if (memcmp(ws.V, V0, sizeof(V0)) != 0 319 || memcmp(ws.C, C0, sizeof(C0)) != 0) { 320 pr_err("The prng self test state test " 321 "for the SHA-512 mode failed\n"); 322 prng_errorflag = PRNG_SELFTEST_FAILED; 323 return -EIO; 324 } 325 326 /* generate random bytes */ 327 cpacf_prno(CPACF_PRNO_SHA512_DRNG_GEN, 328 &ws, buf, sizeof(buf), NULL, 0); 329 cpacf_prno(CPACF_PRNO_SHA512_DRNG_GEN, 330 &ws, buf, sizeof(buf), NULL, 0); 331 332 /* check against expected data */ 333 if (memcmp(buf, random, sizeof(random)) != 0) { 334 pr_err("The prng self test data test " 335 "for the SHA-512 mode failed\n"); 336 prng_errorflag = PRNG_SELFTEST_FAILED; 337 return -EIO; 338 } 339 340 return 0; 341 } 342 343 344 static int __init prng_sha512_instantiate(void) 345 { 346 int ret, datalen; 347 u8 seed[64 + 32 + 16]; 348 349 pr_debug("prng runs in SHA-512 mode " 350 "with chunksize=%d and reseed_limit=%u\n", 351 prng_chunk_size, prng_reseed_limit); 352 353 /* memory allocation, prng_data struct init, mutex init */ 354 datalen = sizeof(struct prng_data_s) + prng_chunk_size; 355 if (fips_enabled) 356 datalen += prng_chunk_size; 357 prng_data = kzalloc(datalen, GFP_KERNEL); 358 if (!prng_data) { 359 prng_errorflag = PRNG_INSTANTIATE_FAILED; 360 return -ENOMEM; 361 } 362 mutex_init(&prng_data->mutex); 363 prng_data->buf = ((u8 *)prng_data) + sizeof(struct prng_data_s); 364 365 /* selftest */ 366 ret = prng_sha512_selftest(); 367 if (ret) 368 goto outfree; 369 370 /* generate initial seed bytestring, with 256 + 128 bits entropy */ 371 ret = generate_entropy(seed, 64 + 32); 372 if (ret != 64 + 32) 373 goto outfree; 374 /* followed by 16 bytes of unique nonce */ 375 get_tod_clock_ext(seed + 64 + 32); 376 377 /* initial seed of the prno drng */ 378 cpacf_prno(CPACF_PRNO_SHA512_DRNG_SEED, 379 &prng_data->prnows, NULL, 0, seed, sizeof(seed)); 380 381 /* if fips mode is enabled, generate a first block of random 382 bytes for the FIPS 140-2 Conditional Self Test */ 383 if (fips_enabled) { 384 prng_data->prev = prng_data->buf + prng_chunk_size; 385 cpacf_prno(CPACF_PRNO_SHA512_DRNG_GEN, 386 &prng_data->prnows, 387 prng_data->prev, prng_chunk_size, NULL, 0); 388 } 389 390 return 0; 391 392 outfree: 393 kfree(prng_data); 394 return ret; 395 } 396 397 398 static void prng_sha512_deinstantiate(void) 399 { 400 pr_debug("The prng module stopped after running in SHA-512 mode\n"); 401 kzfree(prng_data); 402 } 403 404 405 static int prng_sha512_reseed(void) 406 { 407 int ret; 408 u8 seed[64]; 409 410 /* fetch 256 bits of fresh entropy */ 411 ret = generate_entropy(seed, sizeof(seed)); 412 if (ret != sizeof(seed)) 413 return ret; 414 415 /* do a reseed of the prno drng with this bytestring */ 416 cpacf_prno(CPACF_PRNO_SHA512_DRNG_SEED, 417 &prng_data->prnows, NULL, 0, seed, sizeof(seed)); 418 419 return 0; 420 } 421 422 423 static int prng_sha512_generate(u8 *buf, size_t nbytes) 424 { 425 int ret; 426 427 /* reseed needed ? */ 428 if (prng_data->prnows.reseed_counter > prng_reseed_limit) { 429 ret = prng_sha512_reseed(); 430 if (ret) 431 return ret; 432 } 433 434 /* PRNO generate */ 435 cpacf_prno(CPACF_PRNO_SHA512_DRNG_GEN, 436 &prng_data->prnows, buf, nbytes, NULL, 0); 437 438 /* FIPS 140-2 Conditional Self Test */ 439 if (fips_enabled) { 440 if (!memcmp(prng_data->prev, buf, nbytes)) { 441 prng_errorflag = PRNG_GEN_FAILED; 442 return -EILSEQ; 443 } 444 memcpy(prng_data->prev, buf, nbytes); 445 } 446 447 return nbytes; 448 } 449 450 451 /*** file io functions ***/ 452 453 static int prng_open(struct inode *inode, struct file *file) 454 { 455 return nonseekable_open(inode, file); 456 } 457 458 459 static ssize_t prng_tdes_read(struct file *file, char __user *ubuf, 460 size_t nbytes, loff_t *ppos) 461 { 462 int chunk, n, ret = 0; 463 464 /* lock prng_data struct */ 465 if (mutex_lock_interruptible(&prng_data->mutex)) 466 return -ERESTARTSYS; 467 468 while (nbytes) { 469 if (need_resched()) { 470 if (signal_pending(current)) { 471 if (ret == 0) 472 ret = -ERESTARTSYS; 473 break; 474 } 475 /* give mutex free before calling schedule() */ 476 mutex_unlock(&prng_data->mutex); 477 schedule(); 478 /* occopy mutex again */ 479 if (mutex_lock_interruptible(&prng_data->mutex)) { 480 if (ret == 0) 481 ret = -ERESTARTSYS; 482 return ret; 483 } 484 } 485 486 /* 487 * we lose some random bytes if an attacker issues 488 * reads < 8 bytes, but we don't care 489 */ 490 chunk = min_t(int, nbytes, prng_chunk_size); 491 492 /* PRNG only likes multiples of 8 bytes */ 493 n = (chunk + 7) & -8; 494 495 if (prng_data->prngws.reseed_counter > prng_reseed_limit) 496 prng_tdes_seed(8); 497 498 /* if the CPU supports PRNG stckf is present too */ 499 *((unsigned long long *)prng_data->buf) = get_tod_clock_fast(); 500 501 /* 502 * Beside the STCKF the input for the TDES-EDE is the output 503 * of the last operation. We differ here from X9.17 since we 504 * only store one timestamp into the buffer. Padding the whole 505 * buffer with timestamps does not improve security, since 506 * successive stckf have nearly constant offsets. 507 * If an attacker knows the first timestamp it would be 508 * trivial to guess the additional values. One timestamp 509 * is therefore enough and still guarantees unique input values. 510 * 511 * Note: you can still get strict X9.17 conformity by setting 512 * prng_chunk_size to 8 bytes. 513 */ 514 cpacf_kmc(CPACF_KMC_PRNG, prng_data->prngws.parm_block, 515 prng_data->buf, prng_data->buf, n); 516 517 prng_data->prngws.byte_counter += n; 518 prng_data->prngws.reseed_counter += n; 519 520 if (copy_to_user(ubuf, prng_data->buf, chunk)) { 521 ret = -EFAULT; 522 break; 523 } 524 525 nbytes -= chunk; 526 ret += chunk; 527 ubuf += chunk; 528 } 529 530 /* unlock prng_data struct */ 531 mutex_unlock(&prng_data->mutex); 532 533 return ret; 534 } 535 536 537 static ssize_t prng_sha512_read(struct file *file, char __user *ubuf, 538 size_t nbytes, loff_t *ppos) 539 { 540 int n, ret = 0; 541 u8 *p; 542 543 /* if errorflag is set do nothing and return 'broken pipe' */ 544 if (prng_errorflag) 545 return -EPIPE; 546 547 /* lock prng_data struct */ 548 if (mutex_lock_interruptible(&prng_data->mutex)) 549 return -ERESTARTSYS; 550 551 while (nbytes) { 552 if (need_resched()) { 553 if (signal_pending(current)) { 554 if (ret == 0) 555 ret = -ERESTARTSYS; 556 break; 557 } 558 /* give mutex free before calling schedule() */ 559 mutex_unlock(&prng_data->mutex); 560 schedule(); 561 /* occopy mutex again */ 562 if (mutex_lock_interruptible(&prng_data->mutex)) { 563 if (ret == 0) 564 ret = -ERESTARTSYS; 565 return ret; 566 } 567 } 568 if (prng_data->rest) { 569 /* push left over random bytes from the previous read */ 570 p = prng_data->buf + prng_chunk_size - prng_data->rest; 571 n = (nbytes < prng_data->rest) ? 572 nbytes : prng_data->rest; 573 prng_data->rest -= n; 574 } else { 575 /* generate one chunk of random bytes into read buf */ 576 p = prng_data->buf; 577 n = prng_sha512_generate(p, prng_chunk_size); 578 if (n < 0) { 579 ret = n; 580 break; 581 } 582 if (nbytes < prng_chunk_size) { 583 n = nbytes; 584 prng_data->rest = prng_chunk_size - n; 585 } else { 586 n = prng_chunk_size; 587 prng_data->rest = 0; 588 } 589 } 590 if (copy_to_user(ubuf, p, n)) { 591 ret = -EFAULT; 592 break; 593 } 594 ubuf += n; 595 nbytes -= n; 596 ret += n; 597 } 598 599 /* unlock prng_data struct */ 600 mutex_unlock(&prng_data->mutex); 601 602 return ret; 603 } 604 605 606 /*** sysfs stuff ***/ 607 608 static const struct file_operations prng_sha512_fops = { 609 .owner = THIS_MODULE, 610 .open = &prng_open, 611 .release = NULL, 612 .read = &prng_sha512_read, 613 .llseek = noop_llseek, 614 }; 615 static const struct file_operations prng_tdes_fops = { 616 .owner = THIS_MODULE, 617 .open = &prng_open, 618 .release = NULL, 619 .read = &prng_tdes_read, 620 .llseek = noop_llseek, 621 }; 622 623 static struct miscdevice prng_sha512_dev = { 624 .name = "prandom", 625 .minor = MISC_DYNAMIC_MINOR, 626 .mode = 0644, 627 .fops = &prng_sha512_fops, 628 }; 629 static struct miscdevice prng_tdes_dev = { 630 .name = "prandom", 631 .minor = MISC_DYNAMIC_MINOR, 632 .mode = 0644, 633 .fops = &prng_tdes_fops, 634 }; 635 636 637 /* chunksize attribute (ro) */ 638 static ssize_t prng_chunksize_show(struct device *dev, 639 struct device_attribute *attr, 640 char *buf) 641 { 642 return snprintf(buf, PAGE_SIZE, "%u\n", prng_chunk_size); 643 } 644 static DEVICE_ATTR(chunksize, 0444, prng_chunksize_show, NULL); 645 646 /* counter attribute (ro) */ 647 static ssize_t prng_counter_show(struct device *dev, 648 struct device_attribute *attr, 649 char *buf) 650 { 651 u64 counter; 652 653 if (mutex_lock_interruptible(&prng_data->mutex)) 654 return -ERESTARTSYS; 655 if (prng_mode == PRNG_MODE_SHA512) 656 counter = prng_data->prnows.stream_bytes; 657 else 658 counter = prng_data->prngws.byte_counter; 659 mutex_unlock(&prng_data->mutex); 660 661 return snprintf(buf, PAGE_SIZE, "%llu\n", counter); 662 } 663 static DEVICE_ATTR(byte_counter, 0444, prng_counter_show, NULL); 664 665 /* errorflag attribute (ro) */ 666 static ssize_t prng_errorflag_show(struct device *dev, 667 struct device_attribute *attr, 668 char *buf) 669 { 670 return snprintf(buf, PAGE_SIZE, "%d\n", prng_errorflag); 671 } 672 static DEVICE_ATTR(errorflag, 0444, prng_errorflag_show, NULL); 673 674 /* mode attribute (ro) */ 675 static ssize_t prng_mode_show(struct device *dev, 676 struct device_attribute *attr, 677 char *buf) 678 { 679 if (prng_mode == PRNG_MODE_TDES) 680 return snprintf(buf, PAGE_SIZE, "TDES\n"); 681 else 682 return snprintf(buf, PAGE_SIZE, "SHA512\n"); 683 } 684 static DEVICE_ATTR(mode, 0444, prng_mode_show, NULL); 685 686 /* reseed attribute (w) */ 687 static ssize_t prng_reseed_store(struct device *dev, 688 struct device_attribute *attr, 689 const char *buf, size_t count) 690 { 691 if (mutex_lock_interruptible(&prng_data->mutex)) 692 return -ERESTARTSYS; 693 prng_sha512_reseed(); 694 mutex_unlock(&prng_data->mutex); 695 696 return count; 697 } 698 static DEVICE_ATTR(reseed, 0200, NULL, prng_reseed_store); 699 700 /* reseed limit attribute (rw) */ 701 static ssize_t prng_reseed_limit_show(struct device *dev, 702 struct device_attribute *attr, 703 char *buf) 704 { 705 return snprintf(buf, PAGE_SIZE, "%u\n", prng_reseed_limit); 706 } 707 static ssize_t prng_reseed_limit_store(struct device *dev, 708 struct device_attribute *attr, 709 const char *buf, size_t count) 710 { 711 unsigned limit; 712 713 if (sscanf(buf, "%u\n", &limit) != 1) 714 return -EINVAL; 715 716 if (prng_mode == PRNG_MODE_SHA512) { 717 if (limit < PRNG_RESEED_LIMIT_SHA512_LOWER) 718 return -EINVAL; 719 } else { 720 if (limit < PRNG_RESEED_LIMIT_TDES_LOWER) 721 return -EINVAL; 722 } 723 724 prng_reseed_limit = limit; 725 726 return count; 727 } 728 static DEVICE_ATTR(reseed_limit, 0644, 729 prng_reseed_limit_show, prng_reseed_limit_store); 730 731 /* strength attribute (ro) */ 732 static ssize_t prng_strength_show(struct device *dev, 733 struct device_attribute *attr, 734 char *buf) 735 { 736 return snprintf(buf, PAGE_SIZE, "256\n"); 737 } 738 static DEVICE_ATTR(strength, 0444, prng_strength_show, NULL); 739 740 static struct attribute *prng_sha512_dev_attrs[] = { 741 &dev_attr_errorflag.attr, 742 &dev_attr_chunksize.attr, 743 &dev_attr_byte_counter.attr, 744 &dev_attr_mode.attr, 745 &dev_attr_reseed.attr, 746 &dev_attr_reseed_limit.attr, 747 &dev_attr_strength.attr, 748 NULL 749 }; 750 static struct attribute *prng_tdes_dev_attrs[] = { 751 &dev_attr_chunksize.attr, 752 &dev_attr_byte_counter.attr, 753 &dev_attr_mode.attr, 754 NULL 755 }; 756 757 static struct attribute_group prng_sha512_dev_attr_group = { 758 .attrs = prng_sha512_dev_attrs 759 }; 760 static struct attribute_group prng_tdes_dev_attr_group = { 761 .attrs = prng_tdes_dev_attrs 762 }; 763 764 765 /*** module init and exit ***/ 766 767 static int __init prng_init(void) 768 { 769 int ret; 770 771 /* check if the CPU has a PRNG */ 772 if (!cpacf_query_func(CPACF_KMC, CPACF_KMC_PRNG)) 773 return -EOPNOTSUPP; 774 775 /* choose prng mode */ 776 if (prng_mode != PRNG_MODE_TDES) { 777 /* check for MSA5 support for PRNO operations */ 778 if (!cpacf_query_func(CPACF_PRNO, CPACF_PRNO_SHA512_DRNG_GEN)) { 779 if (prng_mode == PRNG_MODE_SHA512) { 780 pr_err("The prng module cannot " 781 "start in SHA-512 mode\n"); 782 return -EOPNOTSUPP; 783 } 784 prng_mode = PRNG_MODE_TDES; 785 } else 786 prng_mode = PRNG_MODE_SHA512; 787 } 788 789 if (prng_mode == PRNG_MODE_SHA512) { 790 791 /* SHA512 mode */ 792 793 if (prng_chunk_size < PRNG_CHUNKSIZE_SHA512_MIN 794 || prng_chunk_size > PRNG_CHUNKSIZE_SHA512_MAX) 795 return -EINVAL; 796 prng_chunk_size = (prng_chunk_size + 0x3f) & ~0x3f; 797 798 if (prng_reseed_limit == 0) 799 prng_reseed_limit = PRNG_RESEED_LIMIT_SHA512; 800 else if (prng_reseed_limit < PRNG_RESEED_LIMIT_SHA512_LOWER) 801 return -EINVAL; 802 803 ret = prng_sha512_instantiate(); 804 if (ret) 805 goto out; 806 807 ret = misc_register(&prng_sha512_dev); 808 if (ret) { 809 prng_sha512_deinstantiate(); 810 goto out; 811 } 812 ret = sysfs_create_group(&prng_sha512_dev.this_device->kobj, 813 &prng_sha512_dev_attr_group); 814 if (ret) { 815 misc_deregister(&prng_sha512_dev); 816 prng_sha512_deinstantiate(); 817 goto out; 818 } 819 820 } else { 821 822 /* TDES mode */ 823 824 if (prng_chunk_size < PRNG_CHUNKSIZE_TDES_MIN 825 || prng_chunk_size > PRNG_CHUNKSIZE_TDES_MAX) 826 return -EINVAL; 827 prng_chunk_size = (prng_chunk_size + 0x07) & ~0x07; 828 829 if (prng_reseed_limit == 0) 830 prng_reseed_limit = PRNG_RESEED_LIMIT_TDES; 831 else if (prng_reseed_limit < PRNG_RESEED_LIMIT_TDES_LOWER) 832 return -EINVAL; 833 834 ret = prng_tdes_instantiate(); 835 if (ret) 836 goto out; 837 838 ret = misc_register(&prng_tdes_dev); 839 if (ret) { 840 prng_tdes_deinstantiate(); 841 goto out; 842 } 843 ret = sysfs_create_group(&prng_tdes_dev.this_device->kobj, 844 &prng_tdes_dev_attr_group); 845 if (ret) { 846 misc_deregister(&prng_tdes_dev); 847 prng_tdes_deinstantiate(); 848 goto out; 849 } 850 851 } 852 853 out: 854 return ret; 855 } 856 857 858 static void __exit prng_exit(void) 859 { 860 if (prng_mode == PRNG_MODE_SHA512) { 861 sysfs_remove_group(&prng_sha512_dev.this_device->kobj, 862 &prng_sha512_dev_attr_group); 863 misc_deregister(&prng_sha512_dev); 864 prng_sha512_deinstantiate(); 865 } else { 866 sysfs_remove_group(&prng_tdes_dev.this_device->kobj, 867 &prng_tdes_dev_attr_group); 868 misc_deregister(&prng_tdes_dev); 869 prng_tdes_deinstantiate(); 870 } 871 } 872 873 module_cpu_feature_match(MSA, prng_init); 874 module_exit(prng_exit); 875