crypto/aead.c

   1 /*
   2  * AEAD: Authenticated Encryption with Associated Data
   3  *
   4  * This file provides API support for AEAD algorithms.
   5  *
   6  * Copyright (c) 2007 Herbert Xu <herbert@gondor.apana.org.au>
   7  *
   8  * This program is free software; you can redistribute it and/or modify it
   9  * under the terms of the GNU General Public License as published by the Free
  10  * Software Foundation; either version 2 of the License, or (at your option)
  11  * any later version.
  12  *
  13  */
  14
  15 #include <crypto/internal/aead.h>
  16 #include <linux/err.h>
  17 #include <linux/init.h>
  18 #include <linux/kernel.h>
  19 #include <linux/module.h>
  20 #include <linux/rtnetlink.h>
  21 #include <linux/slab.h>
  22 #include <linux/seq_file.h>
  23
  24 #include "internal.h"
  25
  26 static int setkey_unaligned(struct crypto_aead *tfm, const u8 *key,
  27                             unsigned int keylen)
  28 {
  29         struct aead_alg *aead = crypto_aead_alg(tfm);
  30         unsigned long alignmask = crypto_aead_alignmask(tfm);
  31         int ret;
  32         u8 *buffer, *alignbuffer;
  33         unsigned long absize;
  34
  35         absize = keylen + alignmask;
  36         buffer = kmalloc(absize, GFP_ATOMIC);
  37         if (!buffer)
  38                 return -ENOMEM;
  39
  40         alignbuffer = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
  41         memcpy(alignbuffer, key, keylen);
  42         ret = aead->setkey(tfm, alignbuffer, keylen);
  43         memset(alignbuffer, 0, keylen);
  44         kfree(buffer);
  45         return ret;
  46 }
  47
  48 static int setkey(struct crypto_aead *tfm, const u8 *key, unsigned int keylen)
  49 {
  50         struct aead_alg *aead = crypto_aead_alg(tfm);
  51         unsigned long alignmask = crypto_aead_alignmask(tfm);
  52
  53         if ((unsigned long)key & alignmask)
  54                 return setkey_unaligned(tfm, key, keylen);
  55
  56         return aead->setkey(tfm, key, keylen);
  57 }
  58
  59 int crypto_aead_setauthsize(struct crypto_aead *tfm, unsigned int authsize)
  60 {
  61         struct aead_tfm *crt = crypto_aead_crt(tfm);
  62         int err;
  63
  64         if (authsize > crypto_aead_alg(tfm)->maxauthsize)
  65                 return -EINVAL;
  66
  67         if (crypto_aead_alg(tfm)->setauthsize) {
  68                 err = crypto_aead_alg(tfm)->setauthsize(crt->base, authsize);
  69                 if (err)
  70                         return err;
  71         }
  72
  73         crypto_aead_crt(crt->base)->authsize = authsize;
  74         crt->authsize = authsize;
  75         return 0;
  76 }
  77 EXPORT_SYMBOL_GPL(crypto_aead_setauthsize);
  78
  79 static unsigned int crypto_aead_ctxsize(struct crypto_alg *alg, u32 type,
  80                                         u32 mask)
  81 {
  82         return alg->cra_ctxsize;
  83 }
  84
  85 static int no_givcrypt(struct aead_givcrypt_request *req)
  86 {
  87         return -ENOSYS;
  88 }
  89
  90 static int crypto_init_aead_ops(struct crypto_tfm *tfm, u32 type, u32 mask)
  91 {
  92         struct aead_alg *alg = &tfm->__crt_alg->cra_aead;
  93         struct aead_tfm *crt = &tfm->crt_aead;
  94
  95         if (max(alg->maxauthsize, alg->ivsize) > PAGE_SIZE / 8)
  96                 return -EINVAL;
  97
  98         crt->setkey = tfm->__crt_alg->cra_flags & CRYPTO_ALG_GENIV ?
  99                       alg->setkey : setkey;
 100         crt->encrypt = alg->encrypt;
 101         crt->decrypt = alg->decrypt;
 102         crt->givencrypt = alg->givencrypt ?: no_givcrypt;
 103         crt->givdecrypt = alg->givdecrypt ?: no_givcrypt;
 104         crt->base = __crypto_aead_cast(tfm);
 105         crt->ivsize = alg->ivsize;
 106         crt->authsize = alg->maxauthsize;
 107
 108         return 0;
 109 }
 110
 111 static void crypto_aead_show(struct seq_file *m, struct crypto_alg *alg)
 112         __attribute__ ((unused));
 113 static void crypto_aead_show(struct seq_file *m, struct crypto_alg *alg)
 114 {
 115         struct aead_alg *aead = &alg->cra_aead;
 116
 117         seq_printf(m, "type         : aead\n");
 118         seq_printf(m, "async        : %s\n", alg->cra_flags & CRYPTO_ALG_ASYNC ?
 119                                              "yes" : "no");
 120         seq_printf(m, "blocksize    : %u\n", alg->cra_blocksize);
 121         seq_printf(m, "ivsize       : %u\n", aead->ivsize);
 122         seq_printf(m, "maxauthsize  : %u\n", aead->maxauthsize);
 123         seq_printf(m, "geniv        : %s\n", aead->geniv ?: "<built-in>");
 124 }
 125
 126 const struct crypto_type crypto_aead_type = {
 127         .ctxsize = crypto_aead_ctxsize,
 128         .init = crypto_init_aead_ops,
 129 #ifdef CONFIG_PROC_FS
 130         .show = crypto_aead_show,
 131 #endif
 132 };
 133 EXPORT_SYMBOL_GPL(crypto_aead_type);
 134
 135 static int aead_null_givencrypt(struct aead_givcrypt_request *req)
 136 {
 137         return crypto_aead_encrypt(&req->areq);
 138 }
 139
 140 static int aead_null_givdecrypt(struct aead_givcrypt_request *req)
 141 {
 142         return crypto_aead_decrypt(&req->areq);
 143 }
 144
 145 static int crypto_init_nivaead_ops(struct crypto_tfm *tfm, u32 type, u32 mask)
 146 {
 147         struct aead_alg *alg = &tfm->__crt_alg->cra_aead;
 148         struct aead_tfm *crt = &tfm->crt_aead;
 149
 150         if (max(alg->maxauthsize, alg->ivsize) > PAGE_SIZE / 8)
 151                 return -EINVAL;
 152
 153         crt->setkey = setkey;
 154         crt->encrypt = alg->encrypt;
 155         crt->decrypt = alg->decrypt;
 156         if (!alg->ivsize) {
 157                 crt->givencrypt = aead_null_givencrypt;
 158                 crt->givdecrypt = aead_null_givdecrypt;
 159         }
 160         crt->base = __crypto_aead_cast(tfm);
 161         crt->ivsize = alg->ivsize;
 162         crt->authsize = alg->maxauthsize;
 163
 164         return 0;
 165 }
 166
 167 static void crypto_nivaead_show(struct seq_file *m, struct crypto_alg *alg)
 168         __attribute__ ((unused));
 169 static void crypto_nivaead_show(struct seq_file *m, struct crypto_alg *alg)
 170 {
 171         struct aead_alg *aead = &alg->cra_aead;
 172
 173         seq_printf(m, "type         : nivaead\n");
 174         seq_printf(m, "async        : %s\n", alg->cra_flags & CRYPTO_ALG_ASYNC ?
 175                                              "yes" : "no");
 176         seq_printf(m, "blocksize    : %u\n", alg->cra_blocksize);
 177         seq_printf(m, "ivsize       : %u\n", aead->ivsize);
 178         seq_printf(m, "maxauthsize  : %u\n", aead->maxauthsize);
 179         seq_printf(m, "geniv        : %s\n", aead->geniv);
 180 }
 181
 182 const struct crypto_type crypto_nivaead_type = {
 183         .ctxsize = crypto_aead_ctxsize,
 184         .init = crypto_init_nivaead_ops,
 185 #ifdef CONFIG_PROC_FS
 186         .show = crypto_nivaead_show,
 187 #endif
 188 };
 189 EXPORT_SYMBOL_GPL(crypto_nivaead_type);
 190
 191 static int crypto_grab_nivaead(struct crypto_aead_spawn *spawn,
 192                                const char *name, u32 type, u32 mask)
 193 {
 194         struct crypto_alg *alg;
 195         int err;
 196
 197         type &= ~(CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_GENIV);
 198         type |= CRYPTO_ALG_TYPE_AEAD;
 199         mask |= CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_GENIV;
 200
 201         alg = crypto_alg_mod_lookup(name, type, mask);
 202         if (IS_ERR(alg))
 203                 return PTR_ERR(alg);
 204
 205         err = crypto_init_spawn(&spawn->base, alg, spawn->base.inst, mask);
 206         crypto_mod_put(alg);
 207         return err;
 208 }
 209
 210 struct crypto_instance *aead_geniv_alloc(struct crypto_template *tmpl,
 211                                          struct rtattr **tb, u32 type,
 212                                          u32 mask)
 213 {
 214         const char *name;
 215         struct crypto_aead_spawn *spawn;
 216         struct crypto_attr_type *algt;
 217         struct crypto_instance *inst;
 218         struct crypto_alg *alg;
 219         int err;
 220
 221         algt = crypto_get_attr_type(tb);
 222         err = PTR_ERR(algt);
 223         if (IS_ERR(algt))
 224                 return ERR_PTR(err);
 225
 226         if ((algt->type ^ (CRYPTO_ALG_TYPE_AEAD | CRYPTO_ALG_GENIV)) &
 227             algt->mask)
 228                 return ERR_PTR(-EINVAL);
 229
 230         name = crypto_attr_alg_name(tb[1]);
 231         err = PTR_ERR(name);
 232         if (IS_ERR(name))
 233                 return ERR_PTR(err);
 234
 235         inst = kzalloc(sizeof(*inst) + sizeof(*spawn), GFP_KERNEL);
 236         if (!inst)
 237                 return ERR_PTR(-ENOMEM);
 238
 239         spawn = crypto_instance_ctx(inst);
 240
 241         /* Ignore async algorithms if necessary. */
 242         mask |= crypto_requires_sync(algt->type, algt->mask);
 243
 244         crypto_set_aead_spawn(spawn, inst);
 245         err = crypto_grab_nivaead(spawn, name, type, mask);
 246         if (err)
 247                 goto err_free_inst;
 248
 249         alg = crypto_aead_spawn_alg(spawn);
 250
 251         err = -EINVAL;
 252         if (!alg->cra_aead.ivsize)
 253                 goto err_drop_alg;
 254
 255         /*
 256          * This is only true if we're constructing an algorithm with its
 257          * default IV generator.  For the default generator we elide the
 258          * template name and double-check the IV generator.
 259          */
 260         if (algt->mask & CRYPTO_ALG_GENIV) {
 261                 if (strcmp(tmpl->name, alg->cra_aead.geniv))
 262                         goto err_drop_alg;
 263
 264                 memcpy(inst->alg.cra_name, alg->cra_name, CRYPTO_MAX_ALG_NAME);
 265                 memcpy(inst->alg.cra_driver_name, alg->cra_driver_name,
 266                        CRYPTO_MAX_ALG_NAME);
 267         } else {
 268                 err = -ENAMETOOLONG;
 269                 if (snprintf(inst->alg.cra_name, CRYPTO_MAX_ALG_NAME,
 270                              "%s(%s)", tmpl->name, alg->cra_name) >=
 271                     CRYPTO_MAX_ALG_NAME)
 272                         goto err_drop_alg;
 273                 if (snprintf(inst->alg.cra_driver_name, CRYPTO_MAX_ALG_NAME,
 274                              "%s(%s)", tmpl->name, alg->cra_driver_name) >=
 275                     CRYPTO_MAX_ALG_NAME)
 276                         goto err_drop_alg;
 277         }
 278
 279         inst->alg.cra_flags = CRYPTO_ALG_TYPE_AEAD | CRYPTO_ALG_GENIV;
 280         inst->alg.cra_flags |= alg->cra_flags & CRYPTO_ALG_ASYNC;
 281         inst->alg.cra_priority = alg->cra_priority;
 282         inst->alg.cra_blocksize = alg->cra_blocksize;
 283         inst->alg.cra_alignmask = alg->cra_alignmask;
 284         inst->alg.cra_type = &crypto_aead_type;
 285
 286         inst->alg.cra_aead.ivsize = alg->cra_aead.ivsize;
 287         inst->alg.cra_aead.maxauthsize = alg->cra_aead.maxauthsize;
 288         inst->alg.cra_aead.geniv = alg->cra_aead.geniv;
 289
 290         inst->alg.cra_aead.setkey = alg->cra_aead.setkey;
 291         inst->alg.cra_aead.setauthsize = alg->cra_aead.setauthsize;
 292         inst->alg.cra_aead.encrypt = alg->cra_aead.encrypt;
 293         inst->alg.cra_aead.decrypt = alg->cra_aead.decrypt;
 294
 295 out:
 296         return inst;
 297
 298 err_drop_alg:
 299         crypto_drop_aead(spawn);
 300 err_free_inst:
 301         kfree(inst);
 302         inst = ERR_PTR(err);
 303         goto out;
 304 }
 305 EXPORT_SYMBOL_GPL(aead_geniv_alloc);
 306
 307 void aead_geniv_free(struct crypto_instance *inst)
 308 {
 309         crypto_drop_aead(crypto_instance_ctx(inst));
 310         kfree(inst);
 311 }
 312 EXPORT_SYMBOL_GPL(aead_geniv_free);
 313
 314 int aead_geniv_init(struct crypto_tfm *tfm)
 315 {
 316         struct crypto_instance *inst = (void *)tfm->__crt_alg;
 317         struct crypto_aead *aead;
 318
 319         aead = crypto_spawn_aead(crypto_instance_ctx(inst));
 320         if (IS_ERR(aead))
 321                 return PTR_ERR(aead);
 322
 323         tfm->crt_aead.base = aead;
 324         tfm->crt_aead.reqsize += crypto_aead_reqsize(aead);
 325
 326         return 0;
 327 }
 328 EXPORT_SYMBOL_GPL(aead_geniv_init);
 329
 330 void aead_geniv_exit(struct crypto_tfm *tfm)
 331 {
 332         crypto_free_aead(tfm->crt_aead.base);
 333 }
 334 EXPORT_SYMBOL_GPL(aead_geniv_exit);
 335
 336 static int crypto_nivaead_default(struct crypto_alg *alg, u32 type, u32 mask)
 337 {
 338         struct rtattr *tb[3];
 339         struct {
 340                 struct rtattr attr;
 341                 struct crypto_attr_type data;
 342         } ptype;
 343         struct {
 344                 struct rtattr attr;
 345                 struct crypto_attr_alg data;
 346         } palg;
 347         struct crypto_template *tmpl;
 348         struct crypto_instance *inst;
 349         struct crypto_alg *larval;
 350         const char *geniv;
 351         int err;
 352
 353         larval = crypto_larval_lookup(alg->cra_driver_name,
 354                                       CRYPTO_ALG_TYPE_AEAD | CRYPTO_ALG_GENIV,
 355                                       CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_GENIV);
 356         err = PTR_ERR(larval);
 357         if (IS_ERR(larval))
 358                 goto out;
 359
 360         err = -EAGAIN;
 361         if (!crypto_is_larval(larval))
 362                 goto drop_larval;
 363
 364         ptype.attr.rta_len = sizeof(ptype);
 365         ptype.attr.rta_type = CRYPTOA_TYPE;
 366         ptype.data.type = type | CRYPTO_ALG_GENIV;
 367         /* GENIV tells the template that we're making a default geniv. */
 368         ptype.data.mask = mask | CRYPTO_ALG_GENIV;
 369         tb[0] = &ptype.attr;
 370
 371         palg.attr.rta_len = sizeof(palg);
 372         palg.attr.rta_type = CRYPTOA_ALG;
 373         /* Must use the exact name to locate ourselves. */
 374         memcpy(palg.data.name, alg->cra_driver_name, CRYPTO_MAX_ALG_NAME);
 375         tb[1] = &palg.attr;
 376
 377         tb[2] = NULL;
 378
 379         geniv = alg->cra_aead.geniv;
 380
 381         tmpl = crypto_lookup_template(geniv);
 382         err = -ENOENT;
 383         if (!tmpl)
 384                 goto kill_larval;
 385
 386         inst = tmpl->alloc(tb);
 387         err = PTR_ERR(inst);
 388         if (IS_ERR(inst))
 389                 goto put_tmpl;
 390
 391         if ((err = crypto_register_instance(tmpl, inst))) {
 392                 tmpl->free(inst);
 393                 goto put_tmpl;
 394         }
 395
 396         /* Redo the lookup to use the instance we just registered. */
 397         err = -EAGAIN;
 398
 399 put_tmpl:
 400         crypto_tmpl_put(tmpl);
 401 kill_larval:
 402         crypto_larval_kill(larval);
 403 drop_larval:
 404         crypto_mod_put(larval);
 405 out:
 406         crypto_mod_put(alg);
 407         return err;
 408 }
 409
 410 static struct crypto_alg *crypto_lookup_aead(const char *name, u32 type,
 411                                              u32 mask)
 412 {
 413         struct crypto_alg *alg;
 414
 415         alg = crypto_alg_mod_lookup(name, type, mask);
 416         if (IS_ERR(alg))
 417                 return alg;
 418
 419         if (alg->cra_type == &crypto_aead_type)
 420                 return alg;
 421
 422         if (!alg->cra_aead.ivsize)
 423                 return alg;
 424
 425         return ERR_PTR(crypto_nivaead_default(alg, type, mask));
 426 }
 427
 428 int crypto_grab_aead(struct crypto_aead_spawn *spawn, const char *name,
 429                      u32 type, u32 mask)
 430 {
 431         struct crypto_alg *alg;
 432         int err;
 433
 434         type &= ~(CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_GENIV);
 435         type |= CRYPTO_ALG_TYPE_AEAD;
 436         mask &= ~(CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_GENIV);
 437         mask |= CRYPTO_ALG_TYPE_MASK;
 438
 439         alg = crypto_lookup_aead(name, type, mask);
 440         if (IS_ERR(alg))
 441                 return PTR_ERR(alg);
 442
 443         err = crypto_init_spawn(&spawn->base, alg, spawn->base.inst, mask);
 444         crypto_mod_put(alg);
 445         return err;
 446 }
 447 EXPORT_SYMBOL_GPL(crypto_grab_aead);
 448
 449 struct crypto_aead *crypto_alloc_aead(const char *alg_name, u32 type, u32 mask)
 450 {
 451         struct crypto_tfm *tfm;
 452         int err;
 453
 454         type &= ~(CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_GENIV);
 455         type |= CRYPTO_ALG_TYPE_AEAD;
 456         mask &= ~(CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_GENIV);
 457         mask |= CRYPTO_ALG_TYPE_MASK;
 458
 459         for (;;) {
 460                 struct crypto_alg *alg;
 461
 462                 alg = crypto_lookup_aead(alg_name, type, mask);
 463                 if (IS_ERR(alg)) {
 464                         err = PTR_ERR(alg);
 465                         goto err;
 466                 }
 467
 468                 tfm = __crypto_alloc_tfm(alg, type, mask);
 469                 if (!IS_ERR(tfm))
 470                         return __crypto_aead_cast(tfm);
 471
 472                 crypto_mod_put(alg);
 473                 err = PTR_ERR(tfm);
 474
 475 err:
 476                 if (err != -EAGAIN)
 477                         break;
 478                 if (signal_pending(current)) {
 479                         err = -EINTR;
 480                         break;
 481                 }
 482         }
 483
 484         return ERR_PTR(err);
 485 }
 486 EXPORT_SYMBOL_GPL(crypto_alloc_aead);
 487
 488 MODULE_LICENSE("GPL");
 489 MODULE_DESCRIPTION("Authenticated Encryption with Associated Data (AEAD)");