Thomas Gleixner | 59e0b61 | 2019-05-20 19:08:07 +0200 | [diff] [blame] | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
Neil Horman | 17f0f4a | 2008-08-14 22:15:52 +1000 | [diff] [blame] | 2 | /* |
| 3 | * PRNG: Pseudo Random Number Generator |
| 4 | * Based on NIST Recommended PRNG From ANSI X9.31 Appendix A.2.4 using |
| 5 | * AES 128 cipher |
| 6 | * |
| 7 | * (C) Neil Horman <nhorman@tuxdriver.com> |
Neil Horman | 17f0f4a | 2008-08-14 22:15:52 +1000 | [diff] [blame] | 8 | */ |
| 9 | |
Ard Biesheuvel | 0eb76ba | 2020-12-11 13:27:15 +0100 | [diff] [blame] | 10 | #include <crypto/internal/cipher.h> |
Neil Horman | 17f0f4a | 2008-08-14 22:15:52 +1000 | [diff] [blame] | 11 | #include <crypto/internal/rng.h> |
| 12 | #include <linux/err.h> |
| 13 | #include <linux/init.h> |
| 14 | #include <linux/module.h> |
| 15 | #include <linux/moduleparam.h> |
| 16 | #include <linux/string.h> |
| 17 | |
Neil Horman | 17f0f4a | 2008-08-14 22:15:52 +1000 | [diff] [blame] | 18 | #define DEFAULT_PRNG_KEY "0123456789abcdef" |
| 19 | #define DEFAULT_PRNG_KSZ 16 |
| 20 | #define DEFAULT_BLK_SZ 16 |
| 21 | #define DEFAULT_V_SEED "zaybxcwdveuftgsh" |
| 22 | |
| 23 | /* |
| 24 | * Flags for the prng_context flags field |
| 25 | */ |
| 26 | |
| 27 | #define PRNG_FIXED_SIZE 0x1 |
| 28 | #define PRNG_NEED_RESET 0x2 |
| 29 | |
| 30 | /* |
| 31 | * Note: DT is our counter value |
| 32 | * I is our intermediate value |
| 33 | * V is our seed vector |
| 34 | * See http://csrc.nist.gov/groups/STM/cavp/documents/rng/931rngext.pdf |
| 35 | * for implementation details |
| 36 | */ |
| 37 | |
| 38 | |
| 39 | struct prng_context { |
| 40 | spinlock_t prng_lock; |
| 41 | unsigned char rand_data[DEFAULT_BLK_SZ]; |
| 42 | unsigned char last_rand_data[DEFAULT_BLK_SZ]; |
| 43 | unsigned char DT[DEFAULT_BLK_SZ]; |
| 44 | unsigned char I[DEFAULT_BLK_SZ]; |
| 45 | unsigned char V[DEFAULT_BLK_SZ]; |
| 46 | u32 rand_data_valid; |
| 47 | struct crypto_cipher *tfm; |
| 48 | u32 flags; |
| 49 | }; |
| 50 | |
| 51 | static int dbg; |
| 52 | |
| 53 | static void hexdump(char *note, unsigned char *buf, unsigned int len) |
| 54 | { |
| 55 | if (dbg) { |
| 56 | printk(KERN_CRIT "%s", note); |
| 57 | print_hex_dump(KERN_CONT, "", DUMP_PREFIX_OFFSET, |
| 58 | 16, 1, |
| 59 | buf, len, false); |
| 60 | } |
| 61 | } |
| 62 | |
| 63 | #define dbgprint(format, args...) do {\ |
| 64 | if (dbg)\ |
| 65 | printk(format, ##args);\ |
| 66 | } while (0) |
| 67 | |
| 68 | static void xor_vectors(unsigned char *in1, unsigned char *in2, |
| 69 | unsigned char *out, unsigned int size) |
| 70 | { |
| 71 | int i; |
| 72 | |
| 73 | for (i = 0; i < size; i++) |
| 74 | out[i] = in1[i] ^ in2[i]; |
| 75 | |
| 76 | } |
| 77 | /* |
| 78 | * Returns DEFAULT_BLK_SZ bytes of random data per call |
Lucas De Marchi | 25985ed | 2011-03-30 22:57:33 -0300 | [diff] [blame] | 79 | * returns 0 if generation succeeded, <0 if something went wrong |
Neil Horman | 17f0f4a | 2008-08-14 22:15:52 +1000 | [diff] [blame] | 80 | */ |
Neil Horman | 667b629 | 2009-10-19 11:57:02 +0900 | [diff] [blame] | 81 | static int _get_more_prng_bytes(struct prng_context *ctx, int cont_test) |
Neil Horman | 17f0f4a | 2008-08-14 22:15:52 +1000 | [diff] [blame] | 82 | { |
| 83 | int i; |
| 84 | unsigned char tmp[DEFAULT_BLK_SZ]; |
| 85 | unsigned char *output = NULL; |
| 86 | |
| 87 | |
| 88 | dbgprint(KERN_CRIT "Calling _get_more_prng_bytes for context %p\n", |
| 89 | ctx); |
| 90 | |
| 91 | hexdump("Input DT: ", ctx->DT, DEFAULT_BLK_SZ); |
| 92 | hexdump("Input I: ", ctx->I, DEFAULT_BLK_SZ); |
| 93 | hexdump("Input V: ", ctx->V, DEFAULT_BLK_SZ); |
| 94 | |
| 95 | /* |
| 96 | * This algorithm is a 3 stage state machine |
| 97 | */ |
| 98 | for (i = 0; i < 3; i++) { |
| 99 | |
| 100 | switch (i) { |
| 101 | case 0: |
| 102 | /* |
| 103 | * Start by encrypting the counter value |
| 104 | * This gives us an intermediate value I |
| 105 | */ |
| 106 | memcpy(tmp, ctx->DT, DEFAULT_BLK_SZ); |
| 107 | output = ctx->I; |
| 108 | hexdump("tmp stage 0: ", tmp, DEFAULT_BLK_SZ); |
| 109 | break; |
| 110 | case 1: |
| 111 | |
| 112 | /* |
| 113 | * Next xor I with our secret vector V |
| 114 | * encrypt that result to obtain our |
| 115 | * pseudo random data which we output |
| 116 | */ |
| 117 | xor_vectors(ctx->I, ctx->V, tmp, DEFAULT_BLK_SZ); |
| 118 | hexdump("tmp stage 1: ", tmp, DEFAULT_BLK_SZ); |
| 119 | output = ctx->rand_data; |
| 120 | break; |
| 121 | case 2: |
| 122 | /* |
| 123 | * First check that we didn't produce the same |
| 124 | * random data that we did last time around through this |
| 125 | */ |
| 126 | if (!memcmp(ctx->rand_data, ctx->last_rand_data, |
| 127 | DEFAULT_BLK_SZ)) { |
Neil Horman | 667b629 | 2009-10-19 11:57:02 +0900 | [diff] [blame] | 128 | if (cont_test) { |
Neil Horman | c5b1e54 | 2009-02-05 16:01:38 +1100 | [diff] [blame] | 129 | panic("cprng %p Failed repetition check!\n", |
| 130 | ctx); |
| 131 | } |
| 132 | |
Neil Horman | 17f0f4a | 2008-08-14 22:15:52 +1000 | [diff] [blame] | 133 | printk(KERN_ERR |
| 134 | "ctx %p Failed repetition check!\n", |
| 135 | ctx); |
Neil Horman | c5b1e54 | 2009-02-05 16:01:38 +1100 | [diff] [blame] | 136 | |
Neil Horman | 17f0f4a | 2008-08-14 22:15:52 +1000 | [diff] [blame] | 137 | ctx->flags |= PRNG_NEED_RESET; |
| 138 | return -EINVAL; |
| 139 | } |
| 140 | memcpy(ctx->last_rand_data, ctx->rand_data, |
| 141 | DEFAULT_BLK_SZ); |
| 142 | |
| 143 | /* |
| 144 | * Lastly xor the random data with I |
| 145 | * and encrypt that to obtain a new secret vector V |
| 146 | */ |
| 147 | xor_vectors(ctx->rand_data, ctx->I, tmp, |
| 148 | DEFAULT_BLK_SZ); |
| 149 | output = ctx->V; |
| 150 | hexdump("tmp stage 2: ", tmp, DEFAULT_BLK_SZ); |
| 151 | break; |
| 152 | } |
| 153 | |
| 154 | |
| 155 | /* do the encryption */ |
| 156 | crypto_cipher_encrypt_one(ctx->tfm, output, tmp); |
| 157 | |
| 158 | } |
| 159 | |
| 160 | /* |
| 161 | * Now update our DT value |
| 162 | */ |
Jarod Wilson | 09fbf7c | 2008-11-24 21:20:13 +0800 | [diff] [blame] | 163 | for (i = DEFAULT_BLK_SZ - 1; i >= 0; i--) { |
Neil Horman | 17f0f4a | 2008-08-14 22:15:52 +1000 | [diff] [blame] | 164 | ctx->DT[i] += 1; |
| 165 | if (ctx->DT[i] != 0) |
| 166 | break; |
| 167 | } |
| 168 | |
| 169 | dbgprint("Returning new block for context %p\n", ctx); |
| 170 | ctx->rand_data_valid = 0; |
| 171 | |
| 172 | hexdump("Output DT: ", ctx->DT, DEFAULT_BLK_SZ); |
| 173 | hexdump("Output I: ", ctx->I, DEFAULT_BLK_SZ); |
| 174 | hexdump("Output V: ", ctx->V, DEFAULT_BLK_SZ); |
| 175 | hexdump("New Random Data: ", ctx->rand_data, DEFAULT_BLK_SZ); |
| 176 | |
| 177 | return 0; |
| 178 | } |
| 179 | |
| 180 | /* Our exported functions */ |
Neil Horman | 667b629 | 2009-10-19 11:57:02 +0900 | [diff] [blame] | 181 | static int get_prng_bytes(char *buf, size_t nbytes, struct prng_context *ctx, |
| 182 | int do_cont_test) |
Neil Horman | 17f0f4a | 2008-08-14 22:15:52 +1000 | [diff] [blame] | 183 | { |
Neil Horman | 17f0f4a | 2008-08-14 22:15:52 +1000 | [diff] [blame] | 184 | unsigned char *ptr = buf; |
| 185 | unsigned int byte_count = (unsigned int)nbytes; |
| 186 | int err; |
| 187 | |
| 188 | |
Sebastian Andrzej Siewior | ed94070 | 2009-07-03 12:09:41 +0800 | [diff] [blame] | 189 | spin_lock_bh(&ctx->prng_lock); |
Neil Horman | 17f0f4a | 2008-08-14 22:15:52 +1000 | [diff] [blame] | 190 | |
| 191 | err = -EINVAL; |
| 192 | if (ctx->flags & PRNG_NEED_RESET) |
| 193 | goto done; |
| 194 | |
| 195 | /* |
| 196 | * If the FIXED_SIZE flag is on, only return whole blocks of |
| 197 | * pseudo random data |
| 198 | */ |
| 199 | err = -EINVAL; |
| 200 | if (ctx->flags & PRNG_FIXED_SIZE) { |
| 201 | if (nbytes < DEFAULT_BLK_SZ) |
| 202 | goto done; |
| 203 | byte_count = DEFAULT_BLK_SZ; |
| 204 | } |
| 205 | |
Stephan Mueller | cde001e | 2015-03-06 08:26:31 +0100 | [diff] [blame] | 206 | /* |
| 207 | * Return 0 in case of success as mandated by the kernel |
| 208 | * crypto API interface definition. |
| 209 | */ |
| 210 | err = 0; |
Neil Horman | 17f0f4a | 2008-08-14 22:15:52 +1000 | [diff] [blame] | 211 | |
| 212 | dbgprint(KERN_CRIT "getting %d random bytes for context %p\n", |
| 213 | byte_count, ctx); |
| 214 | |
| 215 | |
| 216 | remainder: |
| 217 | if (ctx->rand_data_valid == DEFAULT_BLK_SZ) { |
Neil Horman | 667b629 | 2009-10-19 11:57:02 +0900 | [diff] [blame] | 218 | if (_get_more_prng_bytes(ctx, do_cont_test) < 0) { |
Neil Horman | 17f0f4a | 2008-08-14 22:15:52 +1000 | [diff] [blame] | 219 | memset(buf, 0, nbytes); |
| 220 | err = -EINVAL; |
| 221 | goto done; |
| 222 | } |
| 223 | } |
| 224 | |
| 225 | /* |
Jarod Wilson | aa1a85d | 2008-11-13 22:03:20 +0800 | [diff] [blame] | 226 | * Copy any data less than an entire block |
Neil Horman | 17f0f4a | 2008-08-14 22:15:52 +1000 | [diff] [blame] | 227 | */ |
| 228 | if (byte_count < DEFAULT_BLK_SZ) { |
Jarod Wilson | aa1a85d | 2008-11-13 22:03:20 +0800 | [diff] [blame] | 229 | empty_rbuf: |
Neil Horman | 714b33d | 2013-09-17 08:33:11 -0400 | [diff] [blame] | 230 | while (ctx->rand_data_valid < DEFAULT_BLK_SZ) { |
Neil Horman | 17f0f4a | 2008-08-14 22:15:52 +1000 | [diff] [blame] | 231 | *ptr = ctx->rand_data[ctx->rand_data_valid]; |
| 232 | ptr++; |
| 233 | byte_count--; |
Neil Horman | 714b33d | 2013-09-17 08:33:11 -0400 | [diff] [blame] | 234 | ctx->rand_data_valid++; |
Neil Horman | 17f0f4a | 2008-08-14 22:15:52 +1000 | [diff] [blame] | 235 | if (byte_count == 0) |
| 236 | goto done; |
| 237 | } |
| 238 | } |
| 239 | |
| 240 | /* |
| 241 | * Now copy whole blocks |
| 242 | */ |
| 243 | for (; byte_count >= DEFAULT_BLK_SZ; byte_count -= DEFAULT_BLK_SZ) { |
Jarod Wilson | aa1a85d | 2008-11-13 22:03:20 +0800 | [diff] [blame] | 244 | if (ctx->rand_data_valid == DEFAULT_BLK_SZ) { |
Neil Horman | 667b629 | 2009-10-19 11:57:02 +0900 | [diff] [blame] | 245 | if (_get_more_prng_bytes(ctx, do_cont_test) < 0) { |
Jarod Wilson | aa1a85d | 2008-11-13 22:03:20 +0800 | [diff] [blame] | 246 | memset(buf, 0, nbytes); |
| 247 | err = -EINVAL; |
| 248 | goto done; |
| 249 | } |
Neil Horman | 17f0f4a | 2008-08-14 22:15:52 +1000 | [diff] [blame] | 250 | } |
Jarod Wilson | aa1a85d | 2008-11-13 22:03:20 +0800 | [diff] [blame] | 251 | if (ctx->rand_data_valid > 0) |
| 252 | goto empty_rbuf; |
Neil Horman | 17f0f4a | 2008-08-14 22:15:52 +1000 | [diff] [blame] | 253 | memcpy(ptr, ctx->rand_data, DEFAULT_BLK_SZ); |
| 254 | ctx->rand_data_valid += DEFAULT_BLK_SZ; |
| 255 | ptr += DEFAULT_BLK_SZ; |
| 256 | } |
| 257 | |
| 258 | /* |
Jarod Wilson | aa1a85d | 2008-11-13 22:03:20 +0800 | [diff] [blame] | 259 | * Now go back and get any remaining partial block |
Neil Horman | 17f0f4a | 2008-08-14 22:15:52 +1000 | [diff] [blame] | 260 | */ |
| 261 | if (byte_count) |
| 262 | goto remainder; |
| 263 | |
| 264 | done: |
Sebastian Andrzej Siewior | ed94070 | 2009-07-03 12:09:41 +0800 | [diff] [blame] | 265 | spin_unlock_bh(&ctx->prng_lock); |
Neil Horman | 17f0f4a | 2008-08-14 22:15:52 +1000 | [diff] [blame] | 266 | dbgprint(KERN_CRIT "returning %d from get_prng_bytes in context %p\n", |
| 267 | err, ctx); |
| 268 | return err; |
| 269 | } |
| 270 | |
| 271 | static void free_prng_context(struct prng_context *ctx) |
| 272 | { |
| 273 | crypto_free_cipher(ctx->tfm); |
| 274 | } |
| 275 | |
| 276 | static int reset_prng_context(struct prng_context *ctx, |
Herbert Xu | e7c2422 | 2015-04-21 10:46:44 +0800 | [diff] [blame] | 277 | const unsigned char *key, size_t klen, |
| 278 | const unsigned char *V, const unsigned char *DT) |
Neil Horman | 17f0f4a | 2008-08-14 22:15:52 +1000 | [diff] [blame] | 279 | { |
| 280 | int ret; |
Herbert Xu | e7c2422 | 2015-04-21 10:46:44 +0800 | [diff] [blame] | 281 | const unsigned char *prng_key; |
Neil Horman | 17f0f4a | 2008-08-14 22:15:52 +1000 | [diff] [blame] | 282 | |
Sebastian Andrzej Siewior | ed94070 | 2009-07-03 12:09:41 +0800 | [diff] [blame] | 283 | spin_lock_bh(&ctx->prng_lock); |
Neil Horman | 17f0f4a | 2008-08-14 22:15:52 +1000 | [diff] [blame] | 284 | ctx->flags |= PRNG_NEED_RESET; |
| 285 | |
| 286 | prng_key = (key != NULL) ? key : (unsigned char *)DEFAULT_PRNG_KEY; |
| 287 | |
| 288 | if (!key) |
| 289 | klen = DEFAULT_PRNG_KSZ; |
| 290 | |
| 291 | if (V) |
| 292 | memcpy(ctx->V, V, DEFAULT_BLK_SZ); |
| 293 | else |
| 294 | memcpy(ctx->V, DEFAULT_V_SEED, DEFAULT_BLK_SZ); |
| 295 | |
| 296 | if (DT) |
| 297 | memcpy(ctx->DT, DT, DEFAULT_BLK_SZ); |
| 298 | else |
| 299 | memset(ctx->DT, 0, DEFAULT_BLK_SZ); |
| 300 | |
| 301 | memset(ctx->rand_data, 0, DEFAULT_BLK_SZ); |
| 302 | memset(ctx->last_rand_data, 0, DEFAULT_BLK_SZ); |
| 303 | |
Neil Horman | 17f0f4a | 2008-08-14 22:15:52 +1000 | [diff] [blame] | 304 | ctx->rand_data_valid = DEFAULT_BLK_SZ; |
| 305 | |
| 306 | ret = crypto_cipher_setkey(ctx->tfm, prng_key, klen); |
| 307 | if (ret) { |
| 308 | dbgprint(KERN_CRIT "PRNG: setkey() failed flags=%x\n", |
| 309 | crypto_cipher_get_flags(ctx->tfm)); |
Neil Horman | 17f0f4a | 2008-08-14 22:15:52 +1000 | [diff] [blame] | 310 | goto out; |
| 311 | } |
| 312 | |
Sebastian Andrzej Siewior | fd09d7f | 2009-07-03 12:10:47 +0800 | [diff] [blame] | 313 | ret = 0; |
Neil Horman | 17f0f4a | 2008-08-14 22:15:52 +1000 | [diff] [blame] | 314 | ctx->flags &= ~PRNG_NEED_RESET; |
| 315 | out: |
Sebastian Andrzej Siewior | ed94070 | 2009-07-03 12:09:41 +0800 | [diff] [blame] | 316 | spin_unlock_bh(&ctx->prng_lock); |
Sebastian Andrzej Siewior | fd09d7f | 2009-07-03 12:10:47 +0800 | [diff] [blame] | 317 | return ret; |
Neil Horman | 17f0f4a | 2008-08-14 22:15:52 +1000 | [diff] [blame] | 318 | } |
| 319 | |
| 320 | static int cprng_init(struct crypto_tfm *tfm) |
| 321 | { |
| 322 | struct prng_context *ctx = crypto_tfm_ctx(tfm); |
| 323 | |
| 324 | spin_lock_init(&ctx->prng_lock); |
Sebastian Andrzej Siewior | fd09d7f | 2009-07-03 12:10:47 +0800 | [diff] [blame] | 325 | ctx->tfm = crypto_alloc_cipher("aes", 0, 0); |
| 326 | if (IS_ERR(ctx->tfm)) { |
| 327 | dbgprint(KERN_CRIT "Failed to alloc tfm for context %p\n", |
| 328 | ctx); |
| 329 | return PTR_ERR(ctx->tfm); |
| 330 | } |
Neil Horman | 17f0f4a | 2008-08-14 22:15:52 +1000 | [diff] [blame] | 331 | |
Neil Horman | d7992f4 | 2009-01-28 15:20:51 +1100 | [diff] [blame] | 332 | if (reset_prng_context(ctx, NULL, DEFAULT_PRNG_KSZ, NULL, NULL) < 0) |
| 333 | return -EINVAL; |
| 334 | |
| 335 | /* |
| 336 | * after allocation, we should always force the user to reset |
| 337 | * so they don't inadvertently use the insecure default values |
| 338 | * without specifying them intentially |
| 339 | */ |
| 340 | ctx->flags |= PRNG_NEED_RESET; |
| 341 | return 0; |
Neil Horman | 17f0f4a | 2008-08-14 22:15:52 +1000 | [diff] [blame] | 342 | } |
| 343 | |
| 344 | static void cprng_exit(struct crypto_tfm *tfm) |
| 345 | { |
| 346 | free_prng_context(crypto_tfm_ctx(tfm)); |
| 347 | } |
| 348 | |
Herbert Xu | e7c2422 | 2015-04-21 10:46:44 +0800 | [diff] [blame] | 349 | static int cprng_get_random(struct crypto_rng *tfm, |
| 350 | const u8 *src, unsigned int slen, |
| 351 | u8 *rdata, unsigned int dlen) |
Neil Horman | 17f0f4a | 2008-08-14 22:15:52 +1000 | [diff] [blame] | 352 | { |
| 353 | struct prng_context *prng = crypto_rng_ctx(tfm); |
| 354 | |
Neil Horman | 667b629 | 2009-10-19 11:57:02 +0900 | [diff] [blame] | 355 | return get_prng_bytes(rdata, dlen, prng, 0); |
| 356 | } |
| 357 | |
Neil Horman | 2566578 | 2008-11-05 12:13:14 +0800 | [diff] [blame] | 358 | /* |
| 359 | * This is the cprng_registered reset method the seed value is |
| 360 | * interpreted as the tuple { V KEY DT} |
| 361 | * V and KEY are required during reset, and DT is optional, detected |
| 362 | * as being present by testing the length of the seed |
| 363 | */ |
Herbert Xu | e7c2422 | 2015-04-21 10:46:44 +0800 | [diff] [blame] | 364 | static int cprng_reset(struct crypto_rng *tfm, |
| 365 | const u8 *seed, unsigned int slen) |
Neil Horman | 17f0f4a | 2008-08-14 22:15:52 +1000 | [diff] [blame] | 366 | { |
| 367 | struct prng_context *prng = crypto_rng_ctx(tfm); |
Herbert Xu | e7c2422 | 2015-04-21 10:46:44 +0800 | [diff] [blame] | 368 | const u8 *key = seed + DEFAULT_BLK_SZ; |
| 369 | const u8 *dt = NULL; |
Neil Horman | 17f0f4a | 2008-08-14 22:15:52 +1000 | [diff] [blame] | 370 | |
| 371 | if (slen < DEFAULT_PRNG_KSZ + DEFAULT_BLK_SZ) |
| 372 | return -EINVAL; |
| 373 | |
Neil Horman | 2566578 | 2008-11-05 12:13:14 +0800 | [diff] [blame] | 374 | if (slen >= (2 * DEFAULT_BLK_SZ + DEFAULT_PRNG_KSZ)) |
| 375 | dt = key + DEFAULT_PRNG_KSZ; |
| 376 | |
| 377 | reset_prng_context(prng, key, DEFAULT_PRNG_KSZ, seed, dt); |
Neil Horman | 17f0f4a | 2008-08-14 22:15:52 +1000 | [diff] [blame] | 378 | |
| 379 | if (prng->flags & PRNG_NEED_RESET) |
| 380 | return -EINVAL; |
| 381 | return 0; |
| 382 | } |
| 383 | |
Neil Horman | 667b629 | 2009-10-19 11:57:02 +0900 | [diff] [blame] | 384 | #ifdef CONFIG_CRYPTO_FIPS |
Herbert Xu | e7c2422 | 2015-04-21 10:46:44 +0800 | [diff] [blame] | 385 | static int fips_cprng_get_random(struct crypto_rng *tfm, |
| 386 | const u8 *src, unsigned int slen, |
| 387 | u8 *rdata, unsigned int dlen) |
Jaswinder Singh Rajput | 2f32bfd8 | 2009-11-23 20:25:50 +0800 | [diff] [blame] | 388 | { |
| 389 | struct prng_context *prng = crypto_rng_ctx(tfm); |
| 390 | |
| 391 | return get_prng_bytes(rdata, dlen, prng, 1); |
| 392 | } |
| 393 | |
Herbert Xu | e7c2422 | 2015-04-21 10:46:44 +0800 | [diff] [blame] | 394 | static int fips_cprng_reset(struct crypto_rng *tfm, |
| 395 | const u8 *seed, unsigned int slen) |
Jaswinder Singh Rajput | 2f32bfd8 | 2009-11-23 20:25:50 +0800 | [diff] [blame] | 396 | { |
| 397 | u8 rdata[DEFAULT_BLK_SZ]; |
Herbert Xu | e7c2422 | 2015-04-21 10:46:44 +0800 | [diff] [blame] | 398 | const u8 *key = seed + DEFAULT_BLK_SZ; |
Jaswinder Singh Rajput | 2f32bfd8 | 2009-11-23 20:25:50 +0800 | [diff] [blame] | 399 | int rc; |
| 400 | |
| 401 | struct prng_context *prng = crypto_rng_ctx(tfm); |
| 402 | |
Jarod Wilson | 505172e | 2011-11-09 12:04:06 +0800 | [diff] [blame] | 403 | if (slen < DEFAULT_PRNG_KSZ + DEFAULT_BLK_SZ) |
| 404 | return -EINVAL; |
| 405 | |
| 406 | /* fips strictly requires seed != key */ |
| 407 | if (!memcmp(seed, key, DEFAULT_PRNG_KSZ)) |
| 408 | return -EINVAL; |
| 409 | |
Jaswinder Singh Rajput | 2f32bfd8 | 2009-11-23 20:25:50 +0800 | [diff] [blame] | 410 | rc = cprng_reset(tfm, seed, slen); |
| 411 | |
| 412 | if (!rc) |
| 413 | goto out; |
| 414 | |
| 415 | /* this primes our continuity test */ |
| 416 | rc = get_prng_bytes(rdata, DEFAULT_BLK_SZ, prng, 0); |
| 417 | prng->rand_data_valid = DEFAULT_BLK_SZ; |
| 418 | |
| 419 | out: |
| 420 | return rc; |
| 421 | } |
Jussi Kivilinna | 8fc229a | 2012-07-11 14:20:15 +0300 | [diff] [blame] | 422 | #endif |
Jaswinder Singh Rajput | 2f32bfd8 | 2009-11-23 20:25:50 +0800 | [diff] [blame] | 423 | |
Herbert Xu | e7c2422 | 2015-04-21 10:46:44 +0800 | [diff] [blame] | 424 | static struct rng_alg rng_algs[] = { { |
| 425 | .generate = cprng_get_random, |
| 426 | .seed = cprng_reset, |
| 427 | .seedsize = DEFAULT_PRNG_KSZ + 2 * DEFAULT_BLK_SZ, |
| 428 | .base = { |
| 429 | .cra_name = "stdrng", |
| 430 | .cra_driver_name = "ansi_cprng", |
| 431 | .cra_priority = 100, |
| 432 | .cra_ctxsize = sizeof(struct prng_context), |
| 433 | .cra_module = THIS_MODULE, |
| 434 | .cra_init = cprng_init, |
| 435 | .cra_exit = cprng_exit, |
Jussi Kivilinna | 8fc229a | 2012-07-11 14:20:15 +0300 | [diff] [blame] | 436 | } |
| 437 | #ifdef CONFIG_CRYPTO_FIPS |
| 438 | }, { |
Herbert Xu | e7c2422 | 2015-04-21 10:46:44 +0800 | [diff] [blame] | 439 | .generate = fips_cprng_get_random, |
| 440 | .seed = fips_cprng_reset, |
| 441 | .seedsize = DEFAULT_PRNG_KSZ + 2 * DEFAULT_BLK_SZ, |
| 442 | .base = { |
| 443 | .cra_name = "fips(ansi_cprng)", |
| 444 | .cra_driver_name = "fips_ansi_cprng", |
| 445 | .cra_priority = 300, |
| 446 | .cra_ctxsize = sizeof(struct prng_context), |
| 447 | .cra_module = THIS_MODULE, |
| 448 | .cra_init = cprng_init, |
| 449 | .cra_exit = cprng_exit, |
Neil Horman | 667b629 | 2009-10-19 11:57:02 +0900 | [diff] [blame] | 450 | } |
Neil Horman | 667b629 | 2009-10-19 11:57:02 +0900 | [diff] [blame] | 451 | #endif |
Jussi Kivilinna | 8fc229a | 2012-07-11 14:20:15 +0300 | [diff] [blame] | 452 | } }; |
Neil Horman | 17f0f4a | 2008-08-14 22:15:52 +1000 | [diff] [blame] | 453 | |
| 454 | /* Module initalization */ |
| 455 | static int __init prng_mod_init(void) |
| 456 | { |
Herbert Xu | e7c2422 | 2015-04-21 10:46:44 +0800 | [diff] [blame] | 457 | return crypto_register_rngs(rng_algs, ARRAY_SIZE(rng_algs)); |
Neil Horman | 17f0f4a | 2008-08-14 22:15:52 +1000 | [diff] [blame] | 458 | } |
| 459 | |
| 460 | static void __exit prng_mod_fini(void) |
| 461 | { |
Herbert Xu | e7c2422 | 2015-04-21 10:46:44 +0800 | [diff] [blame] | 462 | crypto_unregister_rngs(rng_algs, ARRAY_SIZE(rng_algs)); |
Neil Horman | 17f0f4a | 2008-08-14 22:15:52 +1000 | [diff] [blame] | 463 | } |
| 464 | |
| 465 | MODULE_LICENSE("GPL"); |
| 466 | MODULE_DESCRIPTION("Software Pseudo Random Number Generator"); |
| 467 | MODULE_AUTHOR("Neil Horman <nhorman@tuxdriver.com>"); |
| 468 | module_param(dbg, int, 0); |
| 469 | MODULE_PARM_DESC(dbg, "Boolean to enable debugging (0/1 == off/on)"); |
Eric Biggers | c4741b2 | 2019-04-11 21:57:42 -0700 | [diff] [blame] | 470 | subsys_initcall(prng_mod_init); |
Neil Horman | 17f0f4a | 2008-08-14 22:15:52 +1000 | [diff] [blame] | 471 | module_exit(prng_mod_fini); |
Kees Cook | 5d26a10 | 2014-11-20 17:05:53 -0800 | [diff] [blame] | 472 | MODULE_ALIAS_CRYPTO("stdrng"); |
Mathias Krause | 3e14dcf | 2015-01-11 18:17:42 +0100 | [diff] [blame] | 473 | MODULE_ALIAS_CRYPTO("ansi_cprng"); |
Ard Biesheuvel | 0eb76ba | 2020-12-11 13:27:15 +0100 | [diff] [blame] | 474 | MODULE_IMPORT_NS(CRYPTO_INTERNAL); |