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