| 1 | /* |
| 2 | * Scatterlist Cryptographic API. |
| 3 | * |
| 4 | * Copyright (c) 2002 James Morris <jmorris@intercode.com.au> |
| 5 | * Copyright (c) 2002 David S. Miller (davem@redhat.com) |
| 6 | * Copyright (c) 2005 Herbert Xu <herbert@gondor.apana.org.au> |
| 7 | * |
| 8 | * Portions derived from Cryptoapi, by Alexander Kjeldaas <astor@fast.no> |
| 9 | * and Nettle, by Niels Möller. |
| 10 | * |
| 11 | * This program is free software; you can redistribute it and/or modify it |
| 12 | * under the terms of the GNU General Public License as published by the Free |
| 13 | * Software Foundation; either version 2 of the License, or (at your option) |
| 14 | * any later version. |
| 15 | * |
| 16 | */ |
| 17 | |
| 18 | #include <linux/err.h> |
| 19 | #include <linux/errno.h> |
| 20 | #include <linux/kernel.h> |
| 21 | #include <linux/kmod.h> |
| 22 | #include <linux/module.h> |
| 23 | #include <linux/param.h> |
| 24 | #include <linux/sched.h> |
| 25 | #include <linux/slab.h> |
| 26 | #include <linux/string.h> |
| 27 | #include "internal.h" |
| 28 | |
| 29 | LIST_HEAD(crypto_alg_list); |
| 30 | EXPORT_SYMBOL_GPL(crypto_alg_list); |
| 31 | DECLARE_RWSEM(crypto_alg_sem); |
| 32 | EXPORT_SYMBOL_GPL(crypto_alg_sem); |
| 33 | |
| 34 | BLOCKING_NOTIFIER_HEAD(crypto_chain); |
| 35 | EXPORT_SYMBOL_GPL(crypto_chain); |
| 36 | |
| 37 | static inline struct crypto_alg *crypto_alg_get(struct crypto_alg *alg) |
| 38 | { |
| 39 | atomic_inc(&alg->cra_refcnt); |
| 40 | return alg; |
| 41 | } |
| 42 | |
| 43 | struct crypto_alg *crypto_mod_get(struct crypto_alg *alg) |
| 44 | { |
| 45 | return try_module_get(alg->cra_module) ? crypto_alg_get(alg) : NULL; |
| 46 | } |
| 47 | EXPORT_SYMBOL_GPL(crypto_mod_get); |
| 48 | |
| 49 | void crypto_mod_put(struct crypto_alg *alg) |
| 50 | { |
| 51 | struct module *module = alg->cra_module; |
| 52 | |
| 53 | crypto_alg_put(alg); |
| 54 | module_put(module); |
| 55 | } |
| 56 | EXPORT_SYMBOL_GPL(crypto_mod_put); |
| 57 | |
| 58 | struct crypto_alg *__crypto_alg_lookup(const char *name, u32 type, u32 mask) |
| 59 | { |
| 60 | struct crypto_alg *q, *alg = NULL; |
| 61 | int best = -2; |
| 62 | |
| 63 | list_for_each_entry(q, &crypto_alg_list, cra_list) { |
| 64 | int exact, fuzzy; |
| 65 | |
| 66 | if (crypto_is_moribund(q)) |
| 67 | continue; |
| 68 | |
| 69 | if ((q->cra_flags ^ type) & mask) |
| 70 | continue; |
| 71 | |
| 72 | if (crypto_is_larval(q) && |
| 73 | ((struct crypto_larval *)q)->mask != mask) |
| 74 | continue; |
| 75 | |
| 76 | exact = !strcmp(q->cra_driver_name, name); |
| 77 | fuzzy = !strcmp(q->cra_name, name); |
| 78 | if (!exact && !(fuzzy && q->cra_priority > best)) |
| 79 | continue; |
| 80 | |
| 81 | if (unlikely(!crypto_mod_get(q))) |
| 82 | continue; |
| 83 | |
| 84 | best = q->cra_priority; |
| 85 | if (alg) |
| 86 | crypto_mod_put(alg); |
| 87 | alg = q; |
| 88 | |
| 89 | if (exact) |
| 90 | break; |
| 91 | } |
| 92 | |
| 93 | return alg; |
| 94 | } |
| 95 | EXPORT_SYMBOL_GPL(__crypto_alg_lookup); |
| 96 | |
| 97 | static void crypto_larval_destroy(struct crypto_alg *alg) |
| 98 | { |
| 99 | struct crypto_larval *larval = (void *)alg; |
| 100 | |
| 101 | BUG_ON(!crypto_is_larval(alg)); |
| 102 | if (larval->adult) |
| 103 | crypto_mod_put(larval->adult); |
| 104 | kfree(larval); |
| 105 | } |
| 106 | |
| 107 | static struct crypto_alg *crypto_larval_alloc(const char *name, u32 type, |
| 108 | u32 mask) |
| 109 | { |
| 110 | struct crypto_alg *alg; |
| 111 | struct crypto_larval *larval; |
| 112 | |
| 113 | larval = kzalloc(sizeof(*larval), GFP_KERNEL); |
| 114 | if (!larval) |
| 115 | return ERR_PTR(-ENOMEM); |
| 116 | |
| 117 | larval->mask = mask; |
| 118 | larval->alg.cra_flags = CRYPTO_ALG_LARVAL | type; |
| 119 | larval->alg.cra_priority = -1; |
| 120 | larval->alg.cra_destroy = crypto_larval_destroy; |
| 121 | |
| 122 | atomic_set(&larval->alg.cra_refcnt, 2); |
| 123 | strlcpy(larval->alg.cra_name, name, CRYPTO_MAX_ALG_NAME); |
| 124 | init_completion(&larval->completion); |
| 125 | |
| 126 | down_write(&crypto_alg_sem); |
| 127 | alg = __crypto_alg_lookup(name, type, mask); |
| 128 | if (!alg) { |
| 129 | alg = &larval->alg; |
| 130 | list_add(&alg->cra_list, &crypto_alg_list); |
| 131 | } |
| 132 | up_write(&crypto_alg_sem); |
| 133 | |
| 134 | if (alg != &larval->alg) |
| 135 | kfree(larval); |
| 136 | |
| 137 | return alg; |
| 138 | } |
| 139 | |
| 140 | void crypto_larval_kill(struct crypto_alg *alg) |
| 141 | { |
| 142 | struct crypto_larval *larval = (void *)alg; |
| 143 | |
| 144 | down_write(&crypto_alg_sem); |
| 145 | list_del(&alg->cra_list); |
| 146 | up_write(&crypto_alg_sem); |
| 147 | complete_all(&larval->completion); |
| 148 | crypto_alg_put(alg); |
| 149 | } |
| 150 | EXPORT_SYMBOL_GPL(crypto_larval_kill); |
| 151 | |
| 152 | static struct crypto_alg *crypto_larval_wait(struct crypto_alg *alg) |
| 153 | { |
| 154 | struct crypto_larval *larval = (void *)alg; |
| 155 | |
| 156 | wait_for_completion_interruptible_timeout(&larval->completion, 60 * HZ); |
| 157 | alg = larval->adult; |
| 158 | if (alg) { |
| 159 | if (!crypto_mod_get(alg)) |
| 160 | alg = ERR_PTR(-EAGAIN); |
| 161 | } else |
| 162 | alg = ERR_PTR(-ENOENT); |
| 163 | crypto_mod_put(&larval->alg); |
| 164 | |
| 165 | return alg; |
| 166 | } |
| 167 | |
| 168 | static struct crypto_alg *crypto_alg_lookup(const char *name, u32 type, |
| 169 | u32 mask) |
| 170 | { |
| 171 | struct crypto_alg *alg; |
| 172 | |
| 173 | down_read(&crypto_alg_sem); |
| 174 | alg = __crypto_alg_lookup(name, type, mask); |
| 175 | up_read(&crypto_alg_sem); |
| 176 | |
| 177 | return alg; |
| 178 | } |
| 179 | |
| 180 | struct crypto_alg *crypto_larval_lookup(const char *name, u32 type, u32 mask) |
| 181 | { |
| 182 | struct crypto_alg *alg; |
| 183 | |
| 184 | if (!name) |
| 185 | return ERR_PTR(-ENOENT); |
| 186 | |
| 187 | mask &= ~(CRYPTO_ALG_LARVAL | CRYPTO_ALG_DEAD); |
| 188 | type &= mask; |
| 189 | |
| 190 | alg = try_then_request_module(crypto_alg_lookup(name, type, mask), |
| 191 | name); |
| 192 | if (alg) |
| 193 | return crypto_is_larval(alg) ? crypto_larval_wait(alg) : alg; |
| 194 | |
| 195 | return crypto_larval_alloc(name, type, mask); |
| 196 | } |
| 197 | EXPORT_SYMBOL_GPL(crypto_larval_lookup); |
| 198 | |
| 199 | struct crypto_alg *crypto_alg_mod_lookup(const char *name, u32 type, u32 mask) |
| 200 | { |
| 201 | struct crypto_alg *alg; |
| 202 | struct crypto_alg *larval; |
| 203 | int ok; |
| 204 | |
| 205 | larval = crypto_larval_lookup(name, type, mask); |
| 206 | if (IS_ERR(larval) || !crypto_is_larval(larval)) |
| 207 | return larval; |
| 208 | |
| 209 | ok = crypto_notify(CRYPTO_MSG_ALG_REQUEST, larval); |
| 210 | if (ok == NOTIFY_DONE) { |
| 211 | request_module("cryptomgr"); |
| 212 | ok = crypto_notify(CRYPTO_MSG_ALG_REQUEST, larval); |
| 213 | } |
| 214 | |
| 215 | if (ok == NOTIFY_STOP) |
| 216 | alg = crypto_larval_wait(larval); |
| 217 | else { |
| 218 | crypto_mod_put(larval); |
| 219 | alg = ERR_PTR(-ENOENT); |
| 220 | } |
| 221 | crypto_larval_kill(larval); |
| 222 | return alg; |
| 223 | } |
| 224 | EXPORT_SYMBOL_GPL(crypto_alg_mod_lookup); |
| 225 | |
| 226 | static int crypto_init_ops(struct crypto_tfm *tfm, u32 type, u32 mask) |
| 227 | { |
| 228 | const struct crypto_type *type_obj = tfm->__crt_alg->cra_type; |
| 229 | |
| 230 | if (type_obj) |
| 231 | return type_obj->init(tfm, type, mask); |
| 232 | |
| 233 | switch (crypto_tfm_alg_type(tfm)) { |
| 234 | case CRYPTO_ALG_TYPE_CIPHER: |
| 235 | return crypto_init_cipher_ops(tfm); |
| 236 | |
| 237 | case CRYPTO_ALG_TYPE_DIGEST: |
| 238 | return crypto_init_digest_ops(tfm); |
| 239 | |
| 240 | case CRYPTO_ALG_TYPE_COMPRESS: |
| 241 | return crypto_init_compress_ops(tfm); |
| 242 | |
| 243 | default: |
| 244 | break; |
| 245 | } |
| 246 | |
| 247 | BUG(); |
| 248 | return -EINVAL; |
| 249 | } |
| 250 | |
| 251 | static void crypto_exit_ops(struct crypto_tfm *tfm) |
| 252 | { |
| 253 | const struct crypto_type *type = tfm->__crt_alg->cra_type; |
| 254 | |
| 255 | if (type) { |
| 256 | if (type->exit) |
| 257 | type->exit(tfm); |
| 258 | return; |
| 259 | } |
| 260 | |
| 261 | switch (crypto_tfm_alg_type(tfm)) { |
| 262 | case CRYPTO_ALG_TYPE_CIPHER: |
| 263 | crypto_exit_cipher_ops(tfm); |
| 264 | break; |
| 265 | |
| 266 | case CRYPTO_ALG_TYPE_DIGEST: |
| 267 | crypto_exit_digest_ops(tfm); |
| 268 | break; |
| 269 | |
| 270 | case CRYPTO_ALG_TYPE_COMPRESS: |
| 271 | crypto_exit_compress_ops(tfm); |
| 272 | break; |
| 273 | |
| 274 | default: |
| 275 | BUG(); |
| 276 | |
| 277 | } |
| 278 | } |
| 279 | |
| 280 | static unsigned int crypto_ctxsize(struct crypto_alg *alg, u32 type, u32 mask) |
| 281 | { |
| 282 | const struct crypto_type *type_obj = alg->cra_type; |
| 283 | unsigned int len; |
| 284 | |
| 285 | len = alg->cra_alignmask & ~(crypto_tfm_ctx_alignment() - 1); |
| 286 | if (type_obj) |
| 287 | return len + type_obj->ctxsize(alg, type, mask); |
| 288 | |
| 289 | switch (alg->cra_flags & CRYPTO_ALG_TYPE_MASK) { |
| 290 | default: |
| 291 | BUG(); |
| 292 | |
| 293 | case CRYPTO_ALG_TYPE_CIPHER: |
| 294 | len += crypto_cipher_ctxsize(alg); |
| 295 | break; |
| 296 | |
| 297 | case CRYPTO_ALG_TYPE_DIGEST: |
| 298 | len += crypto_digest_ctxsize(alg); |
| 299 | break; |
| 300 | |
| 301 | case CRYPTO_ALG_TYPE_COMPRESS: |
| 302 | len += crypto_compress_ctxsize(alg); |
| 303 | break; |
| 304 | } |
| 305 | |
| 306 | return len; |
| 307 | } |
| 308 | |
| 309 | void crypto_shoot_alg(struct crypto_alg *alg) |
| 310 | { |
| 311 | down_write(&crypto_alg_sem); |
| 312 | alg->cra_flags |= CRYPTO_ALG_DYING; |
| 313 | up_write(&crypto_alg_sem); |
| 314 | } |
| 315 | EXPORT_SYMBOL_GPL(crypto_shoot_alg); |
| 316 | |
| 317 | struct crypto_tfm *__crypto_alloc_tfm(struct crypto_alg *alg, u32 type, |
| 318 | u32 mask) |
| 319 | { |
| 320 | struct crypto_tfm *tfm = NULL; |
| 321 | unsigned int tfm_size; |
| 322 | int err = -ENOMEM; |
| 323 | |
| 324 | tfm_size = sizeof(*tfm) + crypto_ctxsize(alg, type, mask); |
| 325 | tfm = kzalloc(tfm_size, GFP_KERNEL); |
| 326 | if (tfm == NULL) |
| 327 | goto out_err; |
| 328 | |
| 329 | tfm->__crt_alg = alg; |
| 330 | |
| 331 | err = crypto_init_ops(tfm, type, mask); |
| 332 | if (err) |
| 333 | goto out_free_tfm; |
| 334 | |
| 335 | if (alg->cra_init && (err = alg->cra_init(tfm))) { |
| 336 | if (err == -EAGAIN) |
| 337 | crypto_shoot_alg(alg); |
| 338 | goto cra_init_failed; |
| 339 | } |
| 340 | |
| 341 | goto out; |
| 342 | |
| 343 | cra_init_failed: |
| 344 | crypto_exit_ops(tfm); |
| 345 | out_free_tfm: |
| 346 | kfree(tfm); |
| 347 | out_err: |
| 348 | tfm = ERR_PTR(err); |
| 349 | out: |
| 350 | return tfm; |
| 351 | } |
| 352 | EXPORT_SYMBOL_GPL(__crypto_alloc_tfm); |
| 353 | |
| 354 | /* |
| 355 | * crypto_alloc_base - Locate algorithm and allocate transform |
| 356 | * @alg_name: Name of algorithm |
| 357 | * @type: Type of algorithm |
| 358 | * @mask: Mask for type comparison |
| 359 | * |
| 360 | * crypto_alloc_base() will first attempt to locate an already loaded |
| 361 | * algorithm. If that fails and the kernel supports dynamically loadable |
| 362 | * modules, it will then attempt to load a module of the same name or |
| 363 | * alias. If that fails it will send a query to any loaded crypto manager |
| 364 | * to construct an algorithm on the fly. A refcount is grabbed on the |
| 365 | * algorithm which is then associated with the new transform. |
| 366 | * |
| 367 | * The returned transform is of a non-determinate type. Most people |
| 368 | * should use one of the more specific allocation functions such as |
| 369 | * crypto_alloc_blkcipher. |
| 370 | * |
| 371 | * In case of error the return value is an error pointer. |
| 372 | */ |
| 373 | struct crypto_tfm *crypto_alloc_base(const char *alg_name, u32 type, u32 mask) |
| 374 | { |
| 375 | struct crypto_tfm *tfm; |
| 376 | int err; |
| 377 | |
| 378 | for (;;) { |
| 379 | struct crypto_alg *alg; |
| 380 | |
| 381 | alg = crypto_alg_mod_lookup(alg_name, type, mask); |
| 382 | if (IS_ERR(alg)) { |
| 383 | err = PTR_ERR(alg); |
| 384 | goto err; |
| 385 | } |
| 386 | |
| 387 | tfm = __crypto_alloc_tfm(alg, type, mask); |
| 388 | if (!IS_ERR(tfm)) |
| 389 | return tfm; |
| 390 | |
| 391 | crypto_mod_put(alg); |
| 392 | err = PTR_ERR(tfm); |
| 393 | |
| 394 | err: |
| 395 | if (err != -EAGAIN) |
| 396 | break; |
| 397 | if (signal_pending(current)) { |
| 398 | err = -EINTR; |
| 399 | break; |
| 400 | } |
| 401 | } |
| 402 | |
| 403 | return ERR_PTR(err); |
| 404 | } |
| 405 | EXPORT_SYMBOL_GPL(crypto_alloc_base); |
| 406 | |
| 407 | /* |
| 408 | * crypto_free_tfm - Free crypto transform |
| 409 | * @tfm: Transform to free |
| 410 | * |
| 411 | * crypto_free_tfm() frees up the transform and any associated resources, |
| 412 | * then drops the refcount on the associated algorithm. |
| 413 | */ |
| 414 | void crypto_free_tfm(struct crypto_tfm *tfm) |
| 415 | { |
| 416 | struct crypto_alg *alg; |
| 417 | int size; |
| 418 | |
| 419 | if (unlikely(!tfm)) |
| 420 | return; |
| 421 | |
| 422 | alg = tfm->__crt_alg; |
| 423 | size = sizeof(*tfm) + alg->cra_ctxsize; |
| 424 | |
| 425 | if (alg->cra_exit) |
| 426 | alg->cra_exit(tfm); |
| 427 | crypto_exit_ops(tfm); |
| 428 | crypto_mod_put(alg); |
| 429 | memset(tfm, 0, size); |
| 430 | kfree(tfm); |
| 431 | } |
| 432 | |
| 433 | EXPORT_SYMBOL_GPL(crypto_free_tfm); |
| 434 | |
| 435 | int crypto_has_alg(const char *name, u32 type, u32 mask) |
| 436 | { |
| 437 | int ret = 0; |
| 438 | struct crypto_alg *alg = crypto_alg_mod_lookup(name, type, mask); |
| 439 | |
| 440 | if (!IS_ERR(alg)) { |
| 441 | crypto_mod_put(alg); |
| 442 | ret = 1; |
| 443 | } |
| 444 | |
| 445 | return ret; |
| 446 | } |
| 447 | EXPORT_SYMBOL_GPL(crypto_has_alg); |
| 448 | |
| 449 | MODULE_DESCRIPTION("Cryptographic core API"); |
| 450 | MODULE_LICENSE("GPL"); |