linux/crypto/aead.c
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   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/sched.h>
  22#include <linux/slab.h>
  23#include <linux/seq_file.h>
  24
  25#include "internal.h"
  26
  27static int setkey_unaligned(struct crypto_aead *tfm, const u8 *key,
  28                            unsigned int keylen)
  29{
  30        struct aead_alg *aead = crypto_aead_alg(tfm);
  31        unsigned long alignmask = crypto_aead_alignmask(tfm);
  32        int ret;
  33        u8 *buffer, *alignbuffer;
  34        unsigned long absize;
  35
  36        absize = keylen + alignmask;
  37        buffer = kmalloc(absize, GFP_ATOMIC);
  38        if (!buffer)
  39                return -ENOMEM;
  40
  41        alignbuffer = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
  42        memcpy(alignbuffer, key, keylen);
  43        ret = aead->setkey(tfm, alignbuffer, keylen);
  44        memset(alignbuffer, 0, keylen);
  45        kfree(buffer);
  46        return ret;
  47}
  48
  49static int setkey(struct crypto_aead *tfm, const u8 *key, unsigned int keylen)
  50{
  51        struct aead_alg *aead = crypto_aead_alg(tfm);
  52        unsigned long alignmask = crypto_aead_alignmask(tfm);
  53
  54        if ((unsigned long)key & alignmask)
  55                return setkey_unaligned(tfm, key, keylen);
  56
  57        return aead->setkey(tfm, key, keylen);
  58}
  59
  60int crypto_aead_setauthsize(struct crypto_aead *tfm, unsigned int authsize)
  61{
  62        struct aead_tfm *crt = crypto_aead_crt(tfm);
  63        int err;
  64
  65        if (authsize > crypto_aead_alg(tfm)->maxauthsize)
  66                return -EINVAL;
  67
  68        if (crypto_aead_alg(tfm)->setauthsize) {
  69                err = crypto_aead_alg(tfm)->setauthsize(crt->base, authsize);
  70                if (err)
  71                        return err;
  72        }
  73
  74        crypto_aead_crt(crt->base)->authsize = authsize;
  75        crt->authsize = authsize;
  76        return 0;
  77}
  78EXPORT_SYMBOL_GPL(crypto_aead_setauthsize);
  79
  80static unsigned int crypto_aead_ctxsize(struct crypto_alg *alg, u32 type,
  81                                        u32 mask)
  82{
  83        return alg->cra_ctxsize;
  84}
  85
  86static int no_givcrypt(struct aead_givcrypt_request *req)
  87{
  88        return -ENOSYS;
  89}
  90
  91static int crypto_init_aead_ops(struct crypto_tfm *tfm, u32 type, u32 mask)
  92{
  93        struct aead_alg *alg = &tfm->__crt_alg->cra_aead;
  94        struct aead_tfm *crt = &tfm->crt_aead;
  95
  96        if (max(alg->maxauthsize, alg->ivsize) > PAGE_SIZE / 8)
  97                return -EINVAL;
  98
  99        crt->setkey = tfm->__crt_alg->cra_flags & CRYPTO_ALG_GENIV ?
 100                      alg->setkey : setkey;
 101        crt->encrypt = alg->encrypt;
 102        crt->decrypt = alg->decrypt;
 103        crt->givencrypt = alg->givencrypt ?: no_givcrypt;
 104        crt->givdecrypt = alg->givdecrypt ?: no_givcrypt;
 105        crt->base = __crypto_aead_cast(tfm);
 106        crt->ivsize = alg->ivsize;
 107        crt->authsize = alg->maxauthsize;
 108
 109        return 0;
 110}
 111
 112static void crypto_aead_show(struct seq_file *m, struct crypto_alg *alg)
 113        __attribute__ ((unused));
 114static void crypto_aead_show(struct seq_file *m, struct crypto_alg *alg)
 115{
 116        struct aead_alg *aead = &alg->cra_aead;
 117
 118        seq_printf(m, "type         : aead\n");
 119        seq_printf(m, "async        : %s\n", alg->cra_flags & CRYPTO_ALG_ASYNC ?
 120                                             "yes" : "no");
 121        seq_printf(m, "blocksize    : %u\n", alg->cra_blocksize);
 122        seq_printf(m, "ivsize       : %u\n", aead->ivsize);
 123        seq_printf(m, "maxauthsize  : %u\n", aead->maxauthsize);
 124        seq_printf(m, "geniv        : %s\n", aead->geniv ?: "<built-in>");
 125}
 126
 127const struct crypto_type crypto_aead_type = {
 128        .ctxsize = crypto_aead_ctxsize,
 129        .init = crypto_init_aead_ops,
 130#ifdef CONFIG_PROC_FS
 131        .show = crypto_aead_show,
 132#endif
 133};
 134EXPORT_SYMBOL_GPL(crypto_aead_type);
 135
 136static int aead_null_givencrypt(struct aead_givcrypt_request *req)
 137{
 138        return crypto_aead_encrypt(&req->areq);
 139}
 140
 141static int aead_null_givdecrypt(struct aead_givcrypt_request *req)
 142{
 143        return crypto_aead_decrypt(&req->areq);
 144}
 145
 146static int crypto_init_nivaead_ops(struct crypto_tfm *tfm, u32 type, u32 mask)
 147{
 148        struct aead_alg *alg = &tfm->__crt_alg->cra_aead;
 149        struct aead_tfm *crt = &tfm->crt_aead;
 150
 151        if (max(alg->maxauthsize, alg->ivsize) > PAGE_SIZE / 8)
 152                return -EINVAL;
 153
 154        crt->setkey = setkey;
 155        crt->encrypt = alg->encrypt;
 156        crt->decrypt = alg->decrypt;
 157        if (!alg->ivsize) {
 158                crt->givencrypt = aead_null_givencrypt;
 159                crt->givdecrypt = aead_null_givdecrypt;
 160        }
 161        crt->base = __crypto_aead_cast(tfm);
 162        crt->ivsize = alg->ivsize;
 163        crt->authsize = alg->maxauthsize;
 164
 165        return 0;
 166}
 167
 168static void crypto_nivaead_show(struct seq_file *m, struct crypto_alg *alg)
 169        __attribute__ ((unused));
 170static void crypto_nivaead_show(struct seq_file *m, struct crypto_alg *alg)
 171{
 172        struct aead_alg *aead = &alg->cra_aead;
 173
 174        seq_printf(m, "type         : nivaead\n");
 175        seq_printf(m, "async        : %s\n", alg->cra_flags & CRYPTO_ALG_ASYNC ?
 176                                             "yes" : "no");
 177        seq_printf(m, "blocksize    : %u\n", alg->cra_blocksize);
 178        seq_printf(m, "ivsize       : %u\n", aead->ivsize);
 179        seq_printf(m, "maxauthsize  : %u\n", aead->maxauthsize);
 180        seq_printf(m, "geniv        : %s\n", aead->geniv);
 181}
 182
 183const struct crypto_type crypto_nivaead_type = {
 184        .ctxsize = crypto_aead_ctxsize,
 185        .init = crypto_init_nivaead_ops,
 186#ifdef CONFIG_PROC_FS
 187        .show = crypto_nivaead_show,
 188#endif
 189};
 190EXPORT_SYMBOL_GPL(crypto_nivaead_type);
 191
 192static int crypto_grab_nivaead(struct crypto_aead_spawn *spawn,
 193                               const char *name, u32 type, u32 mask)
 194{
 195        struct crypto_alg *alg;
 196        int err;
 197
 198        type &= ~(CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_GENIV);
 199        type |= CRYPTO_ALG_TYPE_AEAD;
 200        mask |= CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_GENIV;
 201
 202        alg = crypto_alg_mod_lookup(name, type, mask);
 203        if (IS_ERR(alg))
 204                return PTR_ERR(alg);
 205
 206        err = crypto_init_spawn(&spawn->base, alg, spawn->base.inst, mask);
 207        crypto_mod_put(alg);
 208        return err;
 209}
 210
 211struct crypto_instance *aead_geniv_alloc(struct crypto_template *tmpl,
 212                                         struct rtattr **tb, u32 type,
 213                                         u32 mask)
 214{
 215        const char *name;
 216        struct crypto_aead_spawn *spawn;
 217        struct crypto_attr_type *algt;
 218        struct crypto_instance *inst;
 219        struct crypto_alg *alg;
 220        int err;
 221
 222        algt = crypto_get_attr_type(tb);
 223        err = PTR_ERR(algt);
 224        if (IS_ERR(algt))
 225                return ERR_PTR(err);
 226
 227        if ((algt->type ^ (CRYPTO_ALG_TYPE_AEAD | CRYPTO_ALG_GENIV)) &
 228            algt->mask)
 229                return ERR_PTR(-EINVAL);
 230
 231        name = crypto_attr_alg_name(tb[1]);
 232        err = PTR_ERR(name);
 233        if (IS_ERR(name))
 234                return ERR_PTR(err);
 235
 236        inst = kzalloc(sizeof(*inst) + sizeof(*spawn), GFP_KERNEL);
 237        if (!inst)
 238                return ERR_PTR(-ENOMEM);
 239
 240        spawn = crypto_instance_ctx(inst);
 241
 242        /* Ignore async algorithms if necessary. */
 243        mask |= crypto_requires_sync(algt->type, algt->mask);
 244
 245        crypto_set_aead_spawn(spawn, inst);
 246        err = crypto_grab_nivaead(spawn, name, type, mask);
 247        if (err)
 248                goto err_free_inst;
 249
 250        alg = crypto_aead_spawn_alg(spawn);
 251
 252        err = -EINVAL;
 253        if (!alg->cra_aead.ivsize)
 254                goto err_drop_alg;
 255
 256        /*
 257         * This is only true if we're constructing an algorithm with its
 258         * default IV generator.  For the default generator we elide the
 259         * template name and double-check the IV generator.
 260         */
 261        if (algt->mask & CRYPTO_ALG_GENIV) {
 262                if (strcmp(tmpl->name, alg->cra_aead.geniv))
 263                        goto err_drop_alg;
 264
 265                memcpy(inst->alg.cra_name, alg->cra_name, CRYPTO_MAX_ALG_NAME);
 266                memcpy(inst->alg.cra_driver_name, alg->cra_driver_name,
 267                       CRYPTO_MAX_ALG_NAME);
 268        } else {
 269                err = -ENAMETOOLONG;
 270                if (snprintf(inst->alg.cra_name, CRYPTO_MAX_ALG_NAME,
 271                             "%s(%s)", tmpl->name, alg->cra_name) >=
 272                    CRYPTO_MAX_ALG_NAME)
 273                        goto err_drop_alg;
 274                if (snprintf(inst->alg.cra_driver_name, CRYPTO_MAX_ALG_NAME,
 275                             "%s(%s)", tmpl->name, alg->cra_driver_name) >=
 276                    CRYPTO_MAX_ALG_NAME)
 277                        goto err_drop_alg;
 278        }
 279
 280        inst->alg.cra_flags = CRYPTO_ALG_TYPE_AEAD | CRYPTO_ALG_GENIV;
 281        inst->alg.cra_flags |= alg->cra_flags & CRYPTO_ALG_ASYNC;
 282        inst->alg.cra_priority = alg->cra_priority;
 283        inst->alg.cra_blocksize = alg->cra_blocksize;
 284        inst->alg.cra_alignmask = alg->cra_alignmask;
 285        inst->alg.cra_type = &crypto_aead_type;
 286
 287        inst->alg.cra_aead.ivsize = alg->cra_aead.ivsize;
 288        inst->alg.cra_aead.maxauthsize = alg->cra_aead.maxauthsize;
 289        inst->alg.cra_aead.geniv = alg->cra_aead.geniv;
 290
 291        inst->alg.cra_aead.setkey = alg->cra_aead.setkey;
 292        inst->alg.cra_aead.setauthsize = alg->cra_aead.setauthsize;
 293        inst->alg.cra_aead.encrypt = alg->cra_aead.encrypt;
 294        inst->alg.cra_aead.decrypt = alg->cra_aead.decrypt;
 295
 296out:
 297        return inst;
 298
 299err_drop_alg:
 300        crypto_drop_aead(spawn);
 301err_free_inst:
 302        kfree(inst);
 303        inst = ERR_PTR(err);
 304        goto out;
 305}
 306EXPORT_SYMBOL_GPL(aead_geniv_alloc);
 307
 308void aead_geniv_free(struct crypto_instance *inst)
 309{
 310        crypto_drop_aead(crypto_instance_ctx(inst));
 311        kfree(inst);
 312}
 313EXPORT_SYMBOL_GPL(aead_geniv_free);
 314
 315int aead_geniv_init(struct crypto_tfm *tfm)
 316{
 317        struct crypto_instance *inst = (void *)tfm->__crt_alg;
 318        struct crypto_aead *aead;
 319
 320        aead = crypto_spawn_aead(crypto_instance_ctx(inst));
 321        if (IS_ERR(aead))
 322                return PTR_ERR(aead);
 323
 324        tfm->crt_aead.base = aead;
 325        tfm->crt_aead.reqsize += crypto_aead_reqsize(aead);
 326
 327        return 0;
 328}
 329EXPORT_SYMBOL_GPL(aead_geniv_init);
 330
 331void aead_geniv_exit(struct crypto_tfm *tfm)
 332{
 333        crypto_free_aead(tfm->crt_aead.base);
 334}
 335EXPORT_SYMBOL_GPL(aead_geniv_exit);
 336
 337static int crypto_nivaead_default(struct crypto_alg *alg, u32 type, u32 mask)
 338{
 339        struct rtattr *tb[3];
 340        struct {
 341                struct rtattr attr;
 342                struct crypto_attr_type data;
 343        } ptype;
 344        struct {
 345                struct rtattr attr;
 346                struct crypto_attr_alg data;
 347        } palg;
 348        struct crypto_template *tmpl;
 349        struct crypto_instance *inst;
 350        struct crypto_alg *larval;
 351        const char *geniv;
 352        int err;
 353
 354        larval = crypto_larval_lookup(alg->cra_driver_name,
 355                                      CRYPTO_ALG_TYPE_AEAD | CRYPTO_ALG_GENIV,
 356                                      CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_GENIV);
 357        err = PTR_ERR(larval);
 358        if (IS_ERR(larval))
 359                goto out;
 360
 361        err = -EAGAIN;
 362        if (!crypto_is_larval(larval))
 363                goto drop_larval;
 364
 365        ptype.attr.rta_len = sizeof(ptype);
 366        ptype.attr.rta_type = CRYPTOA_TYPE;
 367        ptype.data.type = type | CRYPTO_ALG_GENIV;
 368        /* GENIV tells the template that we're making a default geniv. */
 369        ptype.data.mask = mask | CRYPTO_ALG_GENIV;
 370        tb[0] = &ptype.attr;
 371
 372        palg.attr.rta_len = sizeof(palg);
 373        palg.attr.rta_type = CRYPTOA_ALG;
 374        /* Must use the exact name to locate ourselves. */
 375        memcpy(palg.data.name, alg->cra_driver_name, CRYPTO_MAX_ALG_NAME);
 376        tb[1] = &palg.attr;
 377
 378        tb[2] = NULL;
 379
 380        geniv = alg->cra_aead.geniv;
 381
 382        tmpl = crypto_lookup_template(geniv);
 383        err = -ENOENT;
 384        if (!tmpl)
 385                goto kill_larval;
 386
 387        inst = tmpl->alloc(tb);
 388        err = PTR_ERR(inst);
 389        if (IS_ERR(inst))
 390                goto put_tmpl;
 391
 392        if ((err = crypto_register_instance(tmpl, inst))) {
 393                tmpl->free(inst);
 394                goto put_tmpl;
 395        }
 396
 397        /* Redo the lookup to use the instance we just registered. */
 398        err = -EAGAIN;
 399
 400put_tmpl:
 401        crypto_tmpl_put(tmpl);
 402kill_larval:
 403        crypto_larval_kill(larval);
 404drop_larval:
 405        crypto_mod_put(larval);
 406out:
 407        crypto_mod_put(alg);
 408        return err;
 409}
 410
 411static struct crypto_alg *crypto_lookup_aead(const char *name, u32 type,
 412                                             u32 mask)
 413{
 414        struct crypto_alg *alg;
 415
 416        alg = crypto_alg_mod_lookup(name, type, mask);
 417        if (IS_ERR(alg))
 418                return alg;
 419
 420        if (alg->cra_type == &crypto_aead_type)
 421                return alg;
 422
 423        if (!alg->cra_aead.ivsize)
 424                return alg;
 425
 426        crypto_mod_put(alg);
 427        alg = crypto_alg_mod_lookup(name, type | CRYPTO_ALG_TESTED,
 428                                    mask & ~CRYPTO_ALG_TESTED);
 429        if (IS_ERR(alg))
 430                return alg;
 431
 432        if (alg->cra_type == &crypto_aead_type) {
 433                if ((alg->cra_flags ^ type ^ ~mask) & CRYPTO_ALG_TESTED) {
 434                        crypto_mod_put(alg);
 435                        alg = ERR_PTR(-ENOENT);
 436                }
 437                return alg;
 438        }
 439
 440        BUG_ON(!alg->cra_aead.ivsize);
 441
 442        return ERR_PTR(crypto_nivaead_default(alg, type, mask));
 443}
 444
 445int crypto_grab_aead(struct crypto_aead_spawn *spawn, const char *name,
 446                     u32 type, u32 mask)
 447{
 448        struct crypto_alg *alg;
 449        int err;
 450
 451        type &= ~(CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_GENIV);
 452        type |= CRYPTO_ALG_TYPE_AEAD;
 453        mask &= ~(CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_GENIV);
 454        mask |= CRYPTO_ALG_TYPE_MASK;
 455
 456        alg = crypto_lookup_aead(name, type, mask);
 457        if (IS_ERR(alg))
 458                return PTR_ERR(alg);
 459
 460        err = crypto_init_spawn(&spawn->base, alg, spawn->base.inst, mask);
 461        crypto_mod_put(alg);
 462        return err;
 463}
 464EXPORT_SYMBOL_GPL(crypto_grab_aead);
 465
 466struct crypto_aead *crypto_alloc_aead(const char *alg_name, u32 type, u32 mask)
 467{
 468        struct crypto_tfm *tfm;
 469        int err;
 470
 471        type &= ~(CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_GENIV);
 472        type |= CRYPTO_ALG_TYPE_AEAD;
 473        mask &= ~(CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_GENIV);
 474        mask |= CRYPTO_ALG_TYPE_MASK;
 475
 476        for (;;) {
 477                struct crypto_alg *alg;
 478
 479                alg = crypto_lookup_aead(alg_name, type, mask);
 480                if (IS_ERR(alg)) {
 481                        err = PTR_ERR(alg);
 482                        goto err;
 483                }
 484
 485                tfm = __crypto_alloc_tfm(alg, type, mask);
 486                if (!IS_ERR(tfm))
 487                        return __crypto_aead_cast(tfm);
 488
 489                crypto_mod_put(alg);
 490                err = PTR_ERR(tfm);
 491
 492err:
 493                if (err != -EAGAIN)
 494                        break;
 495                if (signal_pending(current)) {
 496                        err = -EINTR;
 497                        break;
 498                }
 499        }
 500
 501        return ERR_PTR(err);
 502}
 503EXPORT_SYMBOL_GPL(crypto_alloc_aead);
 504
 505MODULE_LICENSE("GPL");
 506MODULE_DESCRIPTION("Authenticated Encryption with Associated Data (AEAD)");
 507
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