crypto/skcipher.c

   1 /*
   2  * Symmetric key cipher operations.
   3  *
   4  * Generic encrypt/decrypt wrapper for ciphers, handles operations across
   5  * multiple page boundaries by using temporary blocks.  In user context,
   6  * the kernel is given a chance to schedule us once per page.
   7  *
   8  * Copyright (c) 2015 Herbert Xu <herbert@gondor.apana.org.au>
   9  *
  10  * This program is free software; you can redistribute it and/or modify it
  11  * under the terms of the GNU General Public License as published by the Free
  12  * Software Foundation; either version 2 of the License, or (at your option)
  13  * any later version.
  14  *
  15  */
  16
  17 #include <crypto/internal/skcipher.h>
  18 #include <linux/bug.h>
  19 #include <linux/cryptouser.h>
  20 #include <linux/module.h>
  21 #include <linux/rtnetlink.h>
  22 #include <linux/seq_file.h>
  23 #include <net/netlink.h>
  24
  25 #include "internal.h"
  26
  27 static unsigned int crypto_skcipher_extsize(struct crypto_alg *alg)
  28 {
  29         if (alg->cra_type == &crypto_blkcipher_type)
  30                 return sizeof(struct crypto_blkcipher *);
  31
  32         if (alg->cra_type == &crypto_ablkcipher_type ||
  33             alg->cra_type == &crypto_givcipher_type)
  34                 return sizeof(struct crypto_ablkcipher *);
  35
  36         return crypto_alg_extsize(alg);
  37 }
  38
  39 static int skcipher_setkey_blkcipher(struct crypto_skcipher *tfm,
  40                                      const u8 *key, unsigned int keylen)
  41 {
  42         struct crypto_blkcipher **ctx = crypto_skcipher_ctx(tfm);
  43         struct crypto_blkcipher *blkcipher = *ctx;
  44         int err;
  45
  46         crypto_blkcipher_clear_flags(blkcipher, ~0);
  47         crypto_blkcipher_set_flags(blkcipher, crypto_skcipher_get_flags(tfm) &
  48                                               CRYPTO_TFM_REQ_MASK);
  49         err = crypto_blkcipher_setkey(blkcipher, key, keylen);
  50         crypto_skcipher_set_flags(tfm, crypto_blkcipher_get_flags(blkcipher) &
  51                                        CRYPTO_TFM_RES_MASK);
  52
  53         return err;
  54 }
  55
  56 static int skcipher_crypt_blkcipher(struct skcipher_request *req,
  57                                     int (*crypt)(struct blkcipher_desc *,
  58                                                  struct scatterlist *,
  59                                                  struct scatterlist *,
  60                                                  unsigned int))
  61 {
  62         struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
  63         struct crypto_blkcipher **ctx = crypto_skcipher_ctx(tfm);
  64         struct blkcipher_desc desc = {
  65                 .tfm = *ctx,
  66                 .info = req->iv,
  67                 .flags = req->base.flags,
  68         };
  69
  70
  71         return crypt(&desc, req->dst, req->src, req->cryptlen);
  72 }
  73
  74 static int skcipher_encrypt_blkcipher(struct skcipher_request *req)
  75 {
  76         struct crypto_skcipher *skcipher = crypto_skcipher_reqtfm(req);
  77         struct crypto_tfm *tfm = crypto_skcipher_tfm(skcipher);
  78         struct blkcipher_alg *alg = &tfm->__crt_alg->cra_blkcipher;
  79
  80         return skcipher_crypt_blkcipher(req, alg->encrypt);
  81 }
  82
  83 static int skcipher_decrypt_blkcipher(struct skcipher_request *req)
  84 {
  85         struct crypto_skcipher *skcipher = crypto_skcipher_reqtfm(req);
  86         struct crypto_tfm *tfm = crypto_skcipher_tfm(skcipher);
  87         struct blkcipher_alg *alg = &tfm->__crt_alg->cra_blkcipher;
  88
  89         return skcipher_crypt_blkcipher(req, alg->decrypt);
  90 }
  91
  92 static void crypto_exit_skcipher_ops_blkcipher(struct crypto_tfm *tfm)
  93 {
  94         struct crypto_blkcipher **ctx = crypto_tfm_ctx(tfm);
  95
  96         crypto_free_blkcipher(*ctx);
  97 }
  98
  99 static int crypto_init_skcipher_ops_blkcipher(struct crypto_tfm *tfm)
 100 {
 101         struct crypto_alg *calg = tfm->__crt_alg;
 102         struct crypto_skcipher *skcipher = __crypto_skcipher_cast(tfm);
 103         struct crypto_blkcipher **ctx = crypto_tfm_ctx(tfm);
 104         struct crypto_blkcipher *blkcipher;
 105         struct crypto_tfm *btfm;
 106
 107         if (!crypto_mod_get(calg))
 108                 return -EAGAIN;
 109
 110         btfm = __crypto_alloc_tfm(calg, CRYPTO_ALG_TYPE_BLKCIPHER,
 111                                         CRYPTO_ALG_TYPE_MASK);
 112         if (IS_ERR(btfm)) {
 113                 crypto_mod_put(calg);
 114                 return PTR_ERR(btfm);
 115         }
 116
 117         blkcipher = __crypto_blkcipher_cast(btfm);
 118         *ctx = blkcipher;
 119         tfm->exit = crypto_exit_skcipher_ops_blkcipher;
 120
 121         skcipher->setkey = skcipher_setkey_blkcipher;
 122         skcipher->encrypt = skcipher_encrypt_blkcipher;
 123         skcipher->decrypt = skcipher_decrypt_blkcipher;
 124
 125         skcipher->ivsize = crypto_blkcipher_ivsize(blkcipher);
 126         skcipher->keysize = calg->cra_blkcipher.max_keysize;
 127
 128         return 0;
 129 }
 130
 131 static int skcipher_setkey_ablkcipher(struct crypto_skcipher *tfm,
 132                                       const u8 *key, unsigned int keylen)
 133 {
 134         struct crypto_ablkcipher **ctx = crypto_skcipher_ctx(tfm);
 135         struct crypto_ablkcipher *ablkcipher = *ctx;
 136         int err;
 137
 138         crypto_ablkcipher_clear_flags(ablkcipher, ~0);
 139         crypto_ablkcipher_set_flags(ablkcipher,
 140                                     crypto_skcipher_get_flags(tfm) &
 141                                     CRYPTO_TFM_REQ_MASK);
 142         err = crypto_ablkcipher_setkey(ablkcipher, key, keylen);
 143         crypto_skcipher_set_flags(tfm,
 144                                   crypto_ablkcipher_get_flags(ablkcipher) &
 145                                   CRYPTO_TFM_RES_MASK);
 146
 147         return err;
 148 }
 149
 150 static int skcipher_crypt_ablkcipher(struct skcipher_request *req,
 151                                      int (*crypt)(struct ablkcipher_request *))
 152 {
 153         struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
 154         struct crypto_ablkcipher **ctx = crypto_skcipher_ctx(tfm);
 155         struct ablkcipher_request *subreq = skcipher_request_ctx(req);
 156
 157         ablkcipher_request_set_tfm(subreq, *ctx);
 158         ablkcipher_request_set_callback(subreq, skcipher_request_flags(req),
 159                                         req->base.complete, req->base.data);
 160         ablkcipher_request_set_crypt(subreq, req->src, req->dst, req->cryptlen,
 161                                      req->iv);
 162
 163         return crypt(subreq);
 164 }
 165
 166 static int skcipher_encrypt_ablkcipher(struct skcipher_request *req)
 167 {
 168         struct crypto_skcipher *skcipher = crypto_skcipher_reqtfm(req);
 169         struct crypto_tfm *tfm = crypto_skcipher_tfm(skcipher);
 170         struct ablkcipher_alg *alg = &tfm->__crt_alg->cra_ablkcipher;
 171
 172         return skcipher_crypt_ablkcipher(req, alg->encrypt);
 173 }
 174
 175 static int skcipher_decrypt_ablkcipher(struct skcipher_request *req)
 176 {
 177         struct crypto_skcipher *skcipher = crypto_skcipher_reqtfm(req);
 178         struct crypto_tfm *tfm = crypto_skcipher_tfm(skcipher);
 179         struct ablkcipher_alg *alg = &tfm->__crt_alg->cra_ablkcipher;
 180
 181         return skcipher_crypt_ablkcipher(req, alg->decrypt);
 182 }
 183
 184 static void crypto_exit_skcipher_ops_ablkcipher(struct crypto_tfm *tfm)
 185 {
 186         struct crypto_ablkcipher **ctx = crypto_tfm_ctx(tfm);
 187
 188         crypto_free_ablkcipher(*ctx);
 189 }
 190
 191 static int crypto_init_skcipher_ops_ablkcipher(struct crypto_tfm *tfm)
 192 {
 193         struct crypto_alg *calg = tfm->__crt_alg;
 194         struct crypto_skcipher *skcipher = __crypto_skcipher_cast(tfm);
 195         struct crypto_ablkcipher **ctx = crypto_tfm_ctx(tfm);
 196         struct crypto_ablkcipher *ablkcipher;
 197         struct crypto_tfm *abtfm;
 198
 199         if (!crypto_mod_get(calg))
 200                 return -EAGAIN;
 201
 202         abtfm = __crypto_alloc_tfm(calg, 0, 0);
 203         if (IS_ERR(abtfm)) {
 204                 crypto_mod_put(calg);
 205                 return PTR_ERR(abtfm);
 206         }
 207
 208         ablkcipher = __crypto_ablkcipher_cast(abtfm);
 209         *ctx = ablkcipher;
 210         tfm->exit = crypto_exit_skcipher_ops_ablkcipher;
 211
 212         skcipher->setkey = skcipher_setkey_ablkcipher;
 213         skcipher->encrypt = skcipher_encrypt_ablkcipher;
 214         skcipher->decrypt = skcipher_decrypt_ablkcipher;
 215
 216         skcipher->ivsize = crypto_ablkcipher_ivsize(ablkcipher);
 217         skcipher->reqsize = crypto_ablkcipher_reqsize(ablkcipher) +
 218                             sizeof(struct ablkcipher_request);
 219         skcipher->keysize = calg->cra_ablkcipher.max_keysize;
 220
 221         return 0;
 222 }
 223
 224 static int skcipher_setkey_unaligned(struct crypto_skcipher *tfm,
 225                                      const u8 *key, unsigned int keylen)
 226 {
 227         unsigned long alignmask = crypto_skcipher_alignmask(tfm);
 228         struct skcipher_alg *cipher = crypto_skcipher_alg(tfm);
 229         u8 *buffer, *alignbuffer;
 230         unsigned long absize;
 231         int ret;
 232
 233         absize = keylen + alignmask;
 234         buffer = kmalloc(absize, GFP_ATOMIC);
 235         if (!buffer)
 236                 return -ENOMEM;
 237
 238         alignbuffer = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
 239         memcpy(alignbuffer, key, keylen);
 240         ret = cipher->setkey(tfm, alignbuffer, keylen);
 241         kzfree(buffer);
 242         return ret;
 243 }
 244
 245 static int skcipher_setkey(struct crypto_skcipher *tfm, const u8 *key,
 246                            unsigned int keylen)
 247 {
 248         struct skcipher_alg *cipher = crypto_skcipher_alg(tfm);
 249         unsigned long alignmask = crypto_skcipher_alignmask(tfm);
 250
 251         if (keylen < cipher->min_keysize || keylen > cipher->max_keysize) {
 252                 crypto_skcipher_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN);
 253                 return -EINVAL;
 254         }
 255
 256         if ((unsigned long)key & alignmask)
 257                 return skcipher_setkey_unaligned(tfm, key, keylen);
 258
 259         return cipher->setkey(tfm, key, keylen);
 260 }
 261
 262 static void crypto_skcipher_exit_tfm(struct crypto_tfm *tfm)
 263 {
 264         struct crypto_skcipher *skcipher = __crypto_skcipher_cast(tfm);
 265         struct skcipher_alg *alg = crypto_skcipher_alg(skcipher);
 266
 267         alg->exit(skcipher);
 268 }
 269
 270 static int crypto_skcipher_init_tfm(struct crypto_tfm *tfm)
 271 {
 272         struct crypto_skcipher *skcipher = __crypto_skcipher_cast(tfm);
 273         struct skcipher_alg *alg = crypto_skcipher_alg(skcipher);
 274
 275         if (tfm->__crt_alg->cra_type == &crypto_blkcipher_type)
 276                 return crypto_init_skcipher_ops_blkcipher(tfm);
 277
 278         if (tfm->__crt_alg->cra_type == &crypto_ablkcipher_type ||
 279             tfm->__crt_alg->cra_type == &crypto_givcipher_type)
 280                 return crypto_init_skcipher_ops_ablkcipher(tfm);
 281
 282         skcipher->setkey = skcipher_setkey;
 283         skcipher->encrypt = alg->encrypt;
 284         skcipher->decrypt = alg->decrypt;
 285         skcipher->ivsize = alg->ivsize;
 286         skcipher->keysize = alg->max_keysize;
 287
 288         if (alg->exit)
 289                 skcipher->base.exit = crypto_skcipher_exit_tfm;
 290
 291         if (alg->init)
 292                 return alg->init(skcipher);
 293
 294         return 0;
 295 }
 296
 297 static void crypto_skcipher_free_instance(struct crypto_instance *inst)
 298 {
 299         struct skcipher_instance *skcipher =
 300                 container_of(inst, struct skcipher_instance, s.base);
 301
 302         skcipher->free(skcipher);
 303 }
 304
 305 static void crypto_skcipher_show(struct seq_file *m, struct crypto_alg *alg)
 306         __attribute__ ((unused));
 307 static void crypto_skcipher_show(struct seq_file *m, struct crypto_alg *alg)
 308 {
 309         struct skcipher_alg *skcipher = container_of(alg, struct skcipher_alg,
 310                                                      base);
 311
 312         seq_printf(m, "type         : skcipher\n");
 313         seq_printf(m, "async        : %s\n",
 314                    alg->cra_flags & CRYPTO_ALG_ASYNC ?  "yes" : "no");
 315         seq_printf(m, "blocksize    : %u\n", alg->cra_blocksize);
 316         seq_printf(m, "min keysize  : %u\n", skcipher->min_keysize);
 317         seq_printf(m, "max keysize  : %u\n", skcipher->max_keysize);
 318         seq_printf(m, "ivsize       : %u\n", skcipher->ivsize);
 319         seq_printf(m, "chunksize    : %u\n", skcipher->chunksize);
 320 }
 321
 322 #ifdef CONFIG_NET
 323 static int crypto_skcipher_report(struct sk_buff *skb, struct crypto_alg *alg)
 324 {
 325         struct crypto_report_blkcipher rblkcipher;
 326         struct skcipher_alg *skcipher = container_of(alg, struct skcipher_alg,
 327                                                      base);
 328
 329         strncpy(rblkcipher.type, "skcipher", sizeof(rblkcipher.type));
 330         strncpy(rblkcipher.geniv, "<none>", sizeof(rblkcipher.geniv));
 331
 332         rblkcipher.blocksize = alg->cra_blocksize;
 333         rblkcipher.min_keysize = skcipher->min_keysize;
 334         rblkcipher.max_keysize = skcipher->max_keysize;
 335         rblkcipher.ivsize = skcipher->ivsize;
 336
 337         if (nla_put(skb, CRYPTOCFGA_REPORT_BLKCIPHER,
 338                     sizeof(struct crypto_report_blkcipher), &rblkcipher))
 339                 goto nla_put_failure;
 340         return 0;
 341
 342 nla_put_failure:
 343         return -EMSGSIZE;
 344 }
 345 #else
 346 static int crypto_skcipher_report(struct sk_buff *skb, struct crypto_alg *alg)
 347 {
 348         return -ENOSYS;
 349 }
 350 #endif
 351
 352 static const struct crypto_type crypto_skcipher_type2 = {
 353         .extsize = crypto_skcipher_extsize,
 354         .init_tfm = crypto_skcipher_init_tfm,
 355         .free = crypto_skcipher_free_instance,
 356 #ifdef CONFIG_PROC_FS
 357         .show = crypto_skcipher_show,
 358 #endif
 359         .report = crypto_skcipher_report,
 360         .maskclear = ~CRYPTO_ALG_TYPE_MASK,
 361         .maskset = CRYPTO_ALG_TYPE_BLKCIPHER_MASK,
 362         .type = CRYPTO_ALG_TYPE_SKCIPHER,
 363         .tfmsize = offsetof(struct crypto_skcipher, base),
 364 };
 365
 366 int crypto_grab_skcipher(struct crypto_skcipher_spawn *spawn,
 367                           const char *name, u32 type, u32 mask)
 368 {
 369         spawn->base.frontend = &crypto_skcipher_type2;
 370         return crypto_grab_spawn(&spawn->base, name, type, mask);
 371 }
 372 EXPORT_SYMBOL_GPL(crypto_grab_skcipher);
 373
 374 struct crypto_skcipher *crypto_alloc_skcipher(const char *alg_name,
 375                                               u32 type, u32 mask)
 376 {
 377         return crypto_alloc_tfm(alg_name, &crypto_skcipher_type2, type, mask);
 378 }
 379 EXPORT_SYMBOL_GPL(crypto_alloc_skcipher);
 380
 381 int crypto_has_skcipher2(const char *alg_name, u32 type, u32 mask)
 382 {
 383         return crypto_type_has_alg(alg_name, &crypto_skcipher_type2,
 384                                    type, mask);
 385 }
 386 EXPORT_SYMBOL_GPL(crypto_has_skcipher2);
 387
 388 static int skcipher_prepare_alg(struct skcipher_alg *alg)
 389 {
 390         struct crypto_alg *base = &alg->base;
 391
 392         if (alg->ivsize > PAGE_SIZE / 8 || alg->chunksize > PAGE_SIZE / 8)
 393                 return -EINVAL;
 394
 395         if (!alg->chunksize)
 396                 alg->chunksize = base->cra_blocksize;
 397
 398         base->cra_type = &crypto_skcipher_type2;
 399         base->cra_flags &= ~CRYPTO_ALG_TYPE_MASK;
 400         base->cra_flags |= CRYPTO_ALG_TYPE_SKCIPHER;
 401
 402         return 0;
 403 }
 404
 405 int crypto_register_skcipher(struct skcipher_alg *alg)
 406 {
 407         struct crypto_alg *base = &alg->base;
 408         int err;
 409
 410         err = skcipher_prepare_alg(alg);
 411         if (err)
 412                 return err;
 413
 414         return crypto_register_alg(base);
 415 }
 416 EXPORT_SYMBOL_GPL(crypto_register_skcipher);
 417
 418 void crypto_unregister_skcipher(struct skcipher_alg *alg)
 419 {
 420         crypto_unregister_alg(&alg->base);
 421 }
 422 EXPORT_SYMBOL_GPL(crypto_unregister_skcipher);
 423
 424 int crypto_register_skciphers(struct skcipher_alg *algs, int count)
 425 {
 426         int i, ret;
 427
 428         for (i = 0; i < count; i++) {
 429                 ret = crypto_register_skcipher(&algs[i]);
 430                 if (ret)
 431                         goto err;
 432         }
 433
 434         return 0;
 435
 436 err:
 437         for (--i; i >= 0; --i)
 438                 crypto_unregister_skcipher(&algs[i]);
 439
 440         return ret;
 441 }
 442 EXPORT_SYMBOL_GPL(crypto_register_skciphers);
 443
 444 void crypto_unregister_skciphers(struct skcipher_alg *algs, int count)
 445 {
 446         int i;
 447
 448         for (i = count - 1; i >= 0; --i)
 449                 crypto_unregister_skcipher(&algs[i]);
 450 }
 451 EXPORT_SYMBOL_GPL(crypto_unregister_skciphers);
 452
 453 int skcipher_register_instance(struct crypto_template *tmpl,
 454                            struct skcipher_instance *inst)
 455 {
 456         int err;
 457
 458         err = skcipher_prepare_alg(&inst->alg);
 459         if (err)
 460                 return err;
 461
 462         return crypto_register_instance(tmpl, skcipher_crypto_instance(inst));
 463 }
 464 EXPORT_SYMBOL_GPL(skcipher_register_instance);
 465
 466 MODULE_LICENSE("GPL");
 467 MODULE_DESCRIPTION("Symmetric key cipher type");