crypto/algapi.c

   1 /*
   2  * Cryptographic API for algorithms (i.e., low-level API).
   3  *
   4  * Copyright (c) 2006 Herbert Xu <herbert@gondor.apana.org.au>
   5  *
   6  * This program is free software; you can redistribute it and/or modify it
   7  * under the terms of the GNU General Public License as published by the Free
   8  * Software Foundation; either version 2 of the License, or (at your option)
   9  * any later version.
  10  *
  11  */
  12
  13 #include <linux/err.h>
  14 #include <linux/errno.h>
  15 #include <linux/init.h>
  16 #include <linux/kernel.h>
  17 #include <linux/list.h>
  18 #include <linux/module.h>
  19 #include <linux/rtnetlink.h>
  20 #include <linux/string.h>
  21
  22 #include "internal.h"
  23
  24 static LIST_HEAD(crypto_template_list);
  25
  26 void crypto_larval_error(const char *name, u32 type, u32 mask)
  27 {
  28         struct crypto_alg *alg;
  29
  30         down_read(&crypto_alg_sem);
  31         alg = __crypto_alg_lookup(name, type, mask);
  32         up_read(&crypto_alg_sem);
  33
  34         if (alg) {
  35                 if (crypto_is_larval(alg)) {
  36                         struct crypto_larval *larval = (void *)alg;
  37                         complete(&larval->completion);
  38                 }
  39                 crypto_mod_put(alg);
  40         }
  41 }
  42 EXPORT_SYMBOL_GPL(crypto_larval_error);
  43
  44 static inline int crypto_set_driver_name(struct crypto_alg *alg)
  45 {
  46         static const char suffix[] = "-generic";
  47         char *driver_name = alg->cra_driver_name;
  48         int len;
  49
  50         if (*driver_name)
  51                 return 0;
  52
  53         len = strlcpy(driver_name, alg->cra_name, CRYPTO_MAX_ALG_NAME);
  54         if (len + sizeof(suffix) > CRYPTO_MAX_ALG_NAME)
  55                 return -ENAMETOOLONG;
  56
  57         memcpy(driver_name + len, suffix, sizeof(suffix));
  58         return 0;
  59 }
  60
  61 static int crypto_check_alg(struct crypto_alg *alg)
  62 {
  63         if (alg->cra_alignmask & (alg->cra_alignmask + 1))
  64                 return -EINVAL;
  65
  66         if (alg->cra_alignmask & alg->cra_blocksize)
  67                 return -EINVAL;
  68
  69         if (alg->cra_blocksize > PAGE_SIZE / 8)
  70                 return -EINVAL;
  71
  72         if (alg->cra_priority < 0)
  73                 return -EINVAL;
  74
  75         return crypto_set_driver_name(alg);
  76 }
  77
  78 static void crypto_destroy_instance(struct crypto_alg *alg)
  79 {
  80         struct crypto_instance *inst = (void *)alg;
  81         struct crypto_template *tmpl = inst->tmpl;
  82
  83         tmpl->free(inst);
  84         crypto_tmpl_put(tmpl);
  85 }
  86
  87 static void crypto_remove_spawns(struct list_head *spawns,
  88                                  struct list_head *list)
  89 {
  90         struct crypto_spawn *spawn, *n;
  91
  92         list_for_each_entry_safe(spawn, n, spawns, list) {
  93                 struct crypto_instance *inst = spawn->inst;
  94                 struct crypto_template *tmpl = inst->tmpl;
  95
  96                 list_del_init(&spawn->list);
  97                 spawn->alg = NULL;
  98
  99                 if (crypto_is_dead(&inst->alg))
 100                         continue;
 101
 102                 inst->alg.cra_flags |= CRYPTO_ALG_DEAD;
 103                 if (!tmpl || !crypto_tmpl_get(tmpl))
 104                         continue;
 105
 106                 crypto_notify(CRYPTO_MSG_ALG_UNREGISTER, &inst->alg);
 107                 list_move(&inst->alg.cra_list, list);
 108                 hlist_del(&inst->list);
 109                 inst->alg.cra_destroy = crypto_destroy_instance;
 110
 111                 if (!list_empty(&inst->alg.cra_users)) {
 112                         if (&n->list == spawns)
 113                                 n = list_entry(inst->alg.cra_users.next,
 114                                                typeof(*n), list);
 115                         __list_splice(&inst->alg.cra_users, spawns->prev);
 116                 }
 117         }
 118 }
 119
 120 static int __crypto_register_alg(struct crypto_alg *alg,
 121                                  struct list_head *list)
 122 {
 123         struct crypto_alg *q;
 124         int ret = -EAGAIN;
 125
 126         if (crypto_is_dead(alg))
 127                 goto out;
 128
 129         INIT_LIST_HEAD(&alg->cra_users);
 130
 131         ret = -EEXIST;
 132
 133         atomic_set(&alg->cra_refcnt, 1);
 134         list_for_each_entry(q, &crypto_alg_list, cra_list) {
 135                 if (q == alg)
 136                         goto out;
 137
 138                 if (crypto_is_moribund(q))
 139                         continue;
 140
 141                 if (crypto_is_larval(q)) {
 142                         struct crypto_larval *larval = (void *)q;
 143
 144                         if (strcmp(alg->cra_name, q->cra_name) &&
 145                             strcmp(alg->cra_driver_name, q->cra_name))
 146                                 continue;
 147
 148                         if (larval->adult)
 149                                 continue;
 150                         if ((q->cra_flags ^ alg->cra_flags) & larval->mask)
 151                                 continue;
 152                         if (!crypto_mod_get(alg))
 153                                 continue;
 154
 155                         larval->adult = alg;
 156                         complete(&larval->completion);
 157                         continue;
 158                 }
 159
 160                 if (strcmp(alg->cra_name, q->cra_name))
 161                         continue;
 162
 163                 if (strcmp(alg->cra_driver_name, q->cra_driver_name) &&
 164                     q->cra_priority > alg->cra_priority)
 165                         continue;
 166
 167                 crypto_remove_spawns(&q->cra_users, list);
 168         }
 169
 170         list_add(&alg->cra_list, &crypto_alg_list);
 171
 172         crypto_notify(CRYPTO_MSG_ALG_REGISTER, alg);
 173         ret = 0;
 174
 175 out:
 176         return ret;
 177 }
 178
 179 static void crypto_remove_final(struct list_head *list)
 180 {
 181         struct crypto_alg *alg;
 182         struct crypto_alg *n;
 183
 184         list_for_each_entry_safe(alg, n, list, cra_list) {
 185                 list_del_init(&alg->cra_list);
 186                 crypto_alg_put(alg);
 187         }
 188 }
 189
 190 int crypto_register_alg(struct crypto_alg *alg)
 191 {
 192         LIST_HEAD(list);
 193         int err;
 194
 195         err = crypto_check_alg(alg);
 196         if (err)
 197                 return err;
 198
 199         down_write(&crypto_alg_sem);
 200         err = __crypto_register_alg(alg, &list);
 201         up_write(&crypto_alg_sem);
 202
 203         crypto_remove_final(&list);
 204         return err;
 205 }
 206 EXPORT_SYMBOL_GPL(crypto_register_alg);
 207
 208 static int crypto_remove_alg(struct crypto_alg *alg, struct list_head *list)
 209 {
 210         if (unlikely(list_empty(&alg->cra_list)))
 211                 return -ENOENT;
 212
 213         alg->cra_flags |= CRYPTO_ALG_DEAD;
 214
 215         crypto_notify(CRYPTO_MSG_ALG_UNREGISTER, alg);
 216         list_del_init(&alg->cra_list);
 217         crypto_remove_spawns(&alg->cra_users, list);
 218
 219         return 0;
 220 }
 221
 222 int crypto_unregister_alg(struct crypto_alg *alg)
 223 {
 224         int ret;
 225         LIST_HEAD(list);
 226
 227         down_write(&crypto_alg_sem);
 228         ret = crypto_remove_alg(alg, &list);
 229         up_write(&crypto_alg_sem);
 230
 231         if (ret)
 232                 return ret;
 233
 234         BUG_ON(atomic_read(&alg->cra_refcnt) != 1);
 235         if (alg->cra_destroy)
 236                 alg->cra_destroy(alg);
 237
 238         crypto_remove_final(&list);
 239         return 0;
 240 }
 241 EXPORT_SYMBOL_GPL(crypto_unregister_alg);
 242
 243 int crypto_register_template(struct crypto_template *tmpl)
 244 {
 245         struct crypto_template *q;
 246         int err = -EEXIST;
 247
 248         down_write(&crypto_alg_sem);
 249
 250         list_for_each_entry(q, &crypto_template_list, list) {
 251                 if (q == tmpl)
 252                         goto out;
 253         }
 254
 255         list_add(&tmpl->list, &crypto_template_list);
 256         crypto_notify(CRYPTO_MSG_TMPL_REGISTER, tmpl);
 257         err = 0;
 258 out:
 259         up_write(&crypto_alg_sem);
 260         return err;
 261 }
 262 EXPORT_SYMBOL_GPL(crypto_register_template);
 263
 264 void crypto_unregister_template(struct crypto_template *tmpl)
 265 {
 266         struct crypto_instance *inst;
 267         struct hlist_node *p, *n;
 268         struct hlist_head *list;
 269         LIST_HEAD(users);
 270
 271         down_write(&crypto_alg_sem);
 272
 273         BUG_ON(list_empty(&tmpl->list));
 274         list_del_init(&tmpl->list);
 275
 276         list = &tmpl->instances;
 277         hlist_for_each_entry(inst, p, list, list) {
 278                 int err = crypto_remove_alg(&inst->alg, &users);
 279                 BUG_ON(err);
 280         }
 281
 282         crypto_notify(CRYPTO_MSG_TMPL_UNREGISTER, tmpl);
 283
 284         up_write(&crypto_alg_sem);
 285
 286         hlist_for_each_entry_safe(inst, p, n, list, list) {
 287                 BUG_ON(atomic_read(&inst->alg.cra_refcnt) != 1);
 288                 tmpl->free(inst);
 289         }
 290         crypto_remove_final(&users);
 291 }
 292 EXPORT_SYMBOL_GPL(crypto_unregister_template);
 293
 294 static struct crypto_template *__crypto_lookup_template(const char *name)
 295 {
 296         struct crypto_template *q, *tmpl = NULL;
 297
 298         down_read(&crypto_alg_sem);
 299         list_for_each_entry(q, &crypto_template_list, list) {
 300                 if (strcmp(q->name, name))
 301                         continue;
 302                 if (unlikely(!crypto_tmpl_get(q)))
 303                         continue;
 304
 305                 tmpl = q;
 306                 break;
 307         }
 308         up_read(&crypto_alg_sem);
 309
 310         return tmpl;
 311 }
 312
 313 struct crypto_template *crypto_lookup_template(const char *name)
 314 {
 315         return try_then_request_module(__crypto_lookup_template(name), name);
 316 }
 317 EXPORT_SYMBOL_GPL(crypto_lookup_template);
 318
 319 int crypto_register_instance(struct crypto_template *tmpl,
 320                              struct crypto_instance *inst)
 321 {
 322         LIST_HEAD(list);
 323         int err = -EINVAL;
 324
 325         if (inst->alg.cra_destroy)
 326                 goto err;
 327
 328         err = crypto_check_alg(&inst->alg);
 329         if (err)
 330                 goto err;
 331
 332         inst->alg.cra_module = tmpl->module;
 333
 334         down_write(&crypto_alg_sem);
 335
 336         err = __crypto_register_alg(&inst->alg, &list);
 337         if (err)
 338                 goto unlock;
 339
 340         hlist_add_head(&inst->list, &tmpl->instances);
 341         inst->tmpl = tmpl;
 342
 343 unlock:
 344         up_write(&crypto_alg_sem);
 345
 346         crypto_remove_final(&list);
 347
 348 err:
 349         return err;
 350 }
 351 EXPORT_SYMBOL_GPL(crypto_register_instance);
 352
 353 int crypto_init_spawn(struct crypto_spawn *spawn, struct crypto_alg *alg,
 354                       struct crypto_instance *inst)
 355 {
 356         int err = -EAGAIN;
 357
 358         spawn->inst = inst;
 359
 360         down_write(&crypto_alg_sem);
 361         if (!crypto_is_moribund(alg)) {
 362                 list_add(&spawn->list, &alg->cra_users);
 363                 spawn->alg = alg;
 364                 err = 0;
 365         }
 366         up_write(&crypto_alg_sem);
 367
 368         return err;
 369 }
 370 EXPORT_SYMBOL_GPL(crypto_init_spawn);
 371
 372 void crypto_drop_spawn(struct crypto_spawn *spawn)
 373 {
 374         down_write(&crypto_alg_sem);
 375         list_del(&spawn->list);
 376         up_write(&crypto_alg_sem);
 377 }
 378 EXPORT_SYMBOL_GPL(crypto_drop_spawn);
 379
 380 struct crypto_tfm *crypto_spawn_tfm(struct crypto_spawn *spawn)
 381 {
 382         struct crypto_alg *alg;
 383         struct crypto_alg *alg2;
 384         struct crypto_tfm *tfm;
 385
 386         down_read(&crypto_alg_sem);
 387         alg = spawn->alg;
 388         alg2 = alg;
 389         if (alg2)
 390                 alg2 = crypto_mod_get(alg2);
 391         up_read(&crypto_alg_sem);
 392
 393         if (!alg2) {
 394                 if (alg)
 395                         crypto_shoot_alg(alg);
 396                 return ERR_PTR(-EAGAIN);
 397         }
 398
 399         tfm = __crypto_alloc_tfm(alg, 0);
 400         if (IS_ERR(tfm))
 401                 crypto_mod_put(alg);
 402
 403         return tfm;
 404 }
 405 EXPORT_SYMBOL_GPL(crypto_spawn_tfm);
 406
 407 int crypto_register_notifier(struct notifier_block *nb)
 408 {
 409         return blocking_notifier_chain_register(&crypto_chain, nb);
 410 }
 411 EXPORT_SYMBOL_GPL(crypto_register_notifier);
 412
 413 int crypto_unregister_notifier(struct notifier_block *nb)
 414 {
 415         return blocking_notifier_chain_unregister(&crypto_chain, nb);
 416 }
 417 EXPORT_SYMBOL_GPL(crypto_unregister_notifier);
 418
 419 struct crypto_alg *crypto_get_attr_alg(void *param, unsigned int len,
 420                                        u32 type, u32 mask)
 421 {
 422         struct rtattr *rta = param;
 423         struct crypto_attr_alg *alga;
 424
 425         if (!RTA_OK(rta, len))
 426                 return ERR_PTR(-EBADR);
 427         if (rta->rta_type != CRYPTOA_ALG || RTA_PAYLOAD(rta) < sizeof(*alga))
 428                 return ERR_PTR(-EINVAL);
 429
 430         alga = RTA_DATA(rta);
 431         alga->name[CRYPTO_MAX_ALG_NAME - 1] = 0;
 432
 433         return crypto_alg_mod_lookup(alga->name, type, mask);
 434 }
 435 EXPORT_SYMBOL_GPL(crypto_get_attr_alg);
 436
 437 struct crypto_instance *crypto_alloc_instance(const char *name,
 438                                               struct crypto_alg *alg)
 439 {
 440         struct crypto_instance *inst;
 441         struct crypto_spawn *spawn;
 442         int err;
 443
 444         inst = kzalloc(sizeof(*inst) + sizeof(*spawn), GFP_KERNEL);
 445         if (!inst)
 446                 return ERR_PTR(-ENOMEM);
 447
 448         err = -ENAMETOOLONG;
 449         if (snprintf(inst->alg.cra_name, CRYPTO_MAX_ALG_NAME, "%s(%s)", name,
 450                      alg->cra_name) >= CRYPTO_MAX_ALG_NAME)
 451                 goto err_free_inst;
 452
 453         if (snprintf(inst->alg.cra_driver_name, CRYPTO_MAX_ALG_NAME, "%s(%s)",
 454                      name, alg->cra_driver_name) >= CRYPTO_MAX_ALG_NAME)
 455                 goto err_free_inst;
 456
 457         spawn = crypto_instance_ctx(inst);
 458         err = crypto_init_spawn(spawn, alg, inst);
 459
 460         if (err)
 461                 goto err_free_inst;
 462
 463         return inst;
 464
 465 err_free_inst:
 466         kfree(inst);
 467         return ERR_PTR(err);
 468 }
 469 EXPORT_SYMBOL_GPL(crypto_alloc_instance);
 470
 471 static int __init crypto_algapi_init(void)
 472 {
 473         crypto_init_proc();
 474         return 0;
 475 }
 476
 477 static void __exit crypto_algapi_exit(void)
 478 {
 479         crypto_exit_proc();
 480 }
 481
 482 module_init(crypto_algapi_init);
 483 module_exit(crypto_algapi_exit);
 484
 485 MODULE_LICENSE("GPL");
 486 MODULE_DESCRIPTION("Cryptographic algorithms API");