crypto/ablkcipher.c

   1 /*
   2  * Asynchronous block chaining cipher operations.
   3  *
   4  * This is the asynchronous version of blkcipher.c indicating completion
   5  * via a callback.
   6  *
   7  * Copyright (c) 2006 Herbert Xu <herbert@gondor.apana.org.au>
   8  *
   9  * This program is free software; you can redistribute it and/or modify it
  10  * under the terms of the GNU General Public License as published by the Free
  11  * Software Foundation; either version 2 of the License, or (at your option)
  12  * any later version.
  13  *
  14  */
  15
  16 #include <crypto/internal/skcipher.h>
  17 #include <linux/err.h>
  18 #include <linux/init.h>
  19 #include <linux/kernel.h>
  20 #include <linux/module.h>
  21 #include <linux/rtnetlink.h>
  22 #include <linux/sched.h>
  23 #include <linux/slab.h>
  24 #include <linux/seq_file.h>
  25
  26 #include "internal.h"
  27
  28 static int setkey_unaligned(struct crypto_ablkcipher *tfm, const u8 *key,
  29                             unsigned int keylen)
  30 {
  31         struct ablkcipher_alg *cipher = crypto_ablkcipher_alg(tfm);
  32         unsigned long alignmask = crypto_ablkcipher_alignmask(tfm);
  33         int ret;
  34         u8 *buffer, *alignbuffer;
  35         unsigned long absize;
  36
  37         absize = keylen + alignmask;
  38         buffer = kmalloc(absize, GFP_ATOMIC);
  39         if (!buffer)
  40                 return -ENOMEM;
  41
  42         alignbuffer = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
  43         memcpy(alignbuffer, key, keylen);
  44         ret = cipher->setkey(tfm, alignbuffer, keylen);
  45         memset(alignbuffer, 0, keylen);
  46         kfree(buffer);
  47         return ret;
  48 }
  49
  50 static int setkey(struct crypto_ablkcipher *tfm, const u8 *key,
  51                   unsigned int keylen)
  52 {
  53         struct ablkcipher_alg *cipher = crypto_ablkcipher_alg(tfm);
  54         unsigned long alignmask = crypto_ablkcipher_alignmask(tfm);
  55
  56         if (keylen < cipher->min_keysize || keylen > cipher->max_keysize) {
  57                 crypto_ablkcipher_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN);
  58                 return -EINVAL;
  59         }
  60
  61         if ((unsigned long)key & alignmask)
  62                 return setkey_unaligned(tfm, key, keylen);
  63
  64         return cipher->setkey(tfm, key, keylen);
  65 }
  66
  67 static unsigned int crypto_ablkcipher_ctxsize(struct crypto_alg *alg, u32 type,
  68                                               u32 mask)
  69 {
  70         return alg->cra_ctxsize;
  71 }
  72
  73 int skcipher_null_givencrypt(struct skcipher_givcrypt_request *req)
  74 {
  75         return crypto_ablkcipher_encrypt(&req->creq);
  76 }
  77
  78 int skcipher_null_givdecrypt(struct skcipher_givcrypt_request *req)
  79 {
  80         return crypto_ablkcipher_decrypt(&req->creq);
  81 }
  82
  83 static int crypto_init_ablkcipher_ops(struct crypto_tfm *tfm, u32 type,
  84                                       u32 mask)
  85 {
  86         struct ablkcipher_alg *alg = &tfm->__crt_alg->cra_ablkcipher;
  87         struct ablkcipher_tfm *crt = &tfm->crt_ablkcipher;
  88
  89         if (alg->ivsize > PAGE_SIZE / 8)
  90                 return -EINVAL;
  91
  92         crt->setkey = setkey;
  93         crt->encrypt = alg->encrypt;
  94         crt->decrypt = alg->decrypt;
  95         if (!alg->ivsize) {
  96                 crt->givencrypt = skcipher_null_givencrypt;
  97                 crt->givdecrypt = skcipher_null_givdecrypt;
  98         }
  99         crt->base = __crypto_ablkcipher_cast(tfm);
 100         crt->ivsize = alg->ivsize;
 101
 102         return 0;
 103 }
 104
 105 static void crypto_ablkcipher_show(struct seq_file *m, struct crypto_alg *alg)
 106         __attribute__ ((unused));
 107 static void crypto_ablkcipher_show(struct seq_file *m, struct crypto_alg *alg)
 108 {
 109         struct ablkcipher_alg *ablkcipher = &alg->cra_ablkcipher;
 110
 111         seq_printf(m, "type         : ablkcipher\n");
 112         seq_printf(m, "async        : %s\n", alg->cra_flags & CRYPTO_ALG_ASYNC ?
 113                                              "yes" : "no");
 114         seq_printf(m, "blocksize    : %u\n", alg->cra_blocksize);
 115         seq_printf(m, "min keysize  : %u\n", ablkcipher->min_keysize);
 116         seq_printf(m, "max keysize  : %u\n", ablkcipher->max_keysize);
 117         seq_printf(m, "ivsize       : %u\n", ablkcipher->ivsize);
 118         seq_printf(m, "geniv        : %s\n", ablkcipher->geniv ?: "<default>");
 119 }
 120
 121 const struct crypto_type crypto_ablkcipher_type = {
 122         .ctxsize = crypto_ablkcipher_ctxsize,
 123         .init = crypto_init_ablkcipher_ops,
 124 #ifdef CONFIG_PROC_FS
 125         .show = crypto_ablkcipher_show,
 126 #endif
 127 };
 128 EXPORT_SYMBOL_GPL(crypto_ablkcipher_type);
 129
 130 static int no_givdecrypt(struct skcipher_givcrypt_request *req)
 131 {
 132         return -ENOSYS;
 133 }
 134
 135 static int crypto_init_givcipher_ops(struct crypto_tfm *tfm, u32 type,
 136                                       u32 mask)
 137 {
 138         struct ablkcipher_alg *alg = &tfm->__crt_alg->cra_ablkcipher;
 139         struct ablkcipher_tfm *crt = &tfm->crt_ablkcipher;
 140
 141         if (alg->ivsize > PAGE_SIZE / 8)
 142                 return -EINVAL;
 143
 144         crt->setkey = tfm->__crt_alg->cra_flags & CRYPTO_ALG_GENIV ?
 145                       alg->setkey : setkey;
 146         crt->encrypt = alg->encrypt;
 147         crt->decrypt = alg->decrypt;
 148         crt->givencrypt = alg->givencrypt;
 149         crt->givdecrypt = alg->givdecrypt ?: no_givdecrypt;
 150         crt->base = __crypto_ablkcipher_cast(tfm);
 151         crt->ivsize = alg->ivsize;
 152
 153         return 0;
 154 }
 155
 156 static void crypto_givcipher_show(struct seq_file *m, struct crypto_alg *alg)
 157         __attribute__ ((unused));
 158 static void crypto_givcipher_show(struct seq_file *m, struct crypto_alg *alg)
 159 {
 160         struct ablkcipher_alg *ablkcipher = &alg->cra_ablkcipher;
 161
 162         seq_printf(m, "type         : givcipher\n");
 163         seq_printf(m, "async        : %s\n", alg->cra_flags & CRYPTO_ALG_ASYNC ?
 164                                              "yes" : "no");
 165         seq_printf(m, "blocksize    : %u\n", alg->cra_blocksize);
 166         seq_printf(m, "min keysize  : %u\n", ablkcipher->min_keysize);
 167         seq_printf(m, "max keysize  : %u\n", ablkcipher->max_keysize);
 168         seq_printf(m, "ivsize       : %u\n", ablkcipher->ivsize);
 169         seq_printf(m, "geniv        : %s\n", ablkcipher->geniv ?: "<built-in>");
 170 }
 171
 172 const struct crypto_type crypto_givcipher_type = {
 173         .ctxsize = crypto_ablkcipher_ctxsize,
 174         .init = crypto_init_givcipher_ops,
 175 #ifdef CONFIG_PROC_FS
 176         .show = crypto_givcipher_show,
 177 #endif
 178 };
 179 EXPORT_SYMBOL_GPL(crypto_givcipher_type);
 180
 181 const char *crypto_default_geniv(const struct crypto_alg *alg)
 182 {
 183         return alg->cra_flags & CRYPTO_ALG_ASYNC ? "eseqiv" : "chainiv";
 184 }
 185
 186 static int crypto_givcipher_default(struct crypto_alg *alg, u32 type, u32 mask)
 187 {
 188         struct rtattr *tb[3];
 189         struct {
 190                 struct rtattr attr;
 191                 struct crypto_attr_type data;
 192         } ptype;
 193         struct {
 194                 struct rtattr attr;
 195                 struct crypto_attr_alg data;
 196         } palg;
 197         struct crypto_template *tmpl;
 198         struct crypto_instance *inst;
 199         struct crypto_alg *larval;
 200         const char *geniv;
 201         int err;
 202
 203         larval = crypto_larval_lookup(alg->cra_driver_name,
 204                                       CRYPTO_ALG_TYPE_GIVCIPHER,
 205                                       CRYPTO_ALG_TYPE_MASK);
 206         err = PTR_ERR(larval);
 207         if (IS_ERR(larval))
 208                 goto out;
 209
 210         err = -EAGAIN;
 211         if (!crypto_is_larval(larval))
 212                 goto drop_larval;
 213
 214         ptype.attr.rta_len = sizeof(ptype);
 215         ptype.attr.rta_type = CRYPTOA_TYPE;
 216         ptype.data.type = type | CRYPTO_ALG_GENIV;
 217         /* GENIV tells the template that we're making a default geniv. */
 218         ptype.data.mask = mask | CRYPTO_ALG_GENIV;
 219         tb[0] = &ptype.attr;
 220
 221         palg.attr.rta_len = sizeof(palg);
 222         palg.attr.rta_type = CRYPTOA_ALG;
 223         /* Must use the exact name to locate ourselves. */
 224         memcpy(palg.data.name, alg->cra_driver_name, CRYPTO_MAX_ALG_NAME);
 225         tb[1] = &palg.attr;
 226
 227         tb[2] = NULL;
 228
 229         if ((alg->cra_flags & CRYPTO_ALG_TYPE_MASK) ==
 230             CRYPTO_ALG_TYPE_BLKCIPHER)
 231                 geniv = alg->cra_blkcipher.geniv;
 232         else
 233                 geniv = alg->cra_ablkcipher.geniv;
 234
 235         if (!geniv)
 236                 geniv = crypto_default_geniv(alg);
 237
 238         tmpl = crypto_lookup_template(geniv);
 239         err = -ENOENT;
 240         if (!tmpl)
 241                 goto kill_larval;
 242
 243         inst = tmpl->alloc(tb);
 244         err = PTR_ERR(inst);
 245         if (IS_ERR(inst))
 246                 goto put_tmpl;
 247
 248         if ((err = crypto_register_instance(tmpl, inst))) {
 249                 tmpl->free(inst);
 250                 goto put_tmpl;
 251         }
 252
 253         /* Redo the lookup to use the instance we just registered. */
 254         err = -EAGAIN;
 255
 256 put_tmpl:
 257         crypto_tmpl_put(tmpl);
 258 kill_larval:
 259         crypto_larval_kill(larval);
 260 drop_larval:
 261         crypto_mod_put(larval);
 262 out:
 263         crypto_mod_put(alg);
 264         return err;
 265 }
 266
 267 static struct crypto_alg *crypto_lookup_skcipher(const char *name, u32 type,
 268                                                  u32 mask)
 269 {
 270         struct crypto_alg *alg;
 271
 272         alg = crypto_alg_mod_lookup(name, type, mask);
 273         if (IS_ERR(alg))
 274                 return alg;
 275
 276         if ((alg->cra_flags & CRYPTO_ALG_TYPE_MASK) ==
 277             CRYPTO_ALG_TYPE_GIVCIPHER)
 278                 return alg;
 279
 280         if (!((alg->cra_flags & CRYPTO_ALG_TYPE_MASK) ==
 281               CRYPTO_ALG_TYPE_BLKCIPHER ? alg->cra_blkcipher.ivsize :
 282                                           alg->cra_ablkcipher.ivsize))
 283                 return alg;
 284
 285         return ERR_PTR(crypto_givcipher_default(alg, type, mask));
 286 }
 287
 288 int crypto_grab_skcipher(struct crypto_skcipher_spawn *spawn, const char *name,
 289                          u32 type, u32 mask)
 290 {
 291         struct crypto_alg *alg;
 292         int err;
 293
 294         type = crypto_skcipher_type(type);
 295         mask = crypto_skcipher_mask(mask);
 296
 297         alg = crypto_lookup_skcipher(name, type, mask);
 298         if (IS_ERR(alg))
 299                 return PTR_ERR(alg);
 300
 301         err = crypto_init_spawn(&spawn->base, alg, spawn->base.inst, mask);
 302         crypto_mod_put(alg);
 303         return err;
 304 }
 305 EXPORT_SYMBOL_GPL(crypto_grab_skcipher);
 306
 307 struct crypto_ablkcipher *crypto_alloc_ablkcipher(const char *alg_name,
 308                                                   u32 type, u32 mask)
 309 {
 310         struct crypto_tfm *tfm;
 311         int err;
 312
 313         type = crypto_skcipher_type(type);
 314         mask = crypto_skcipher_mask(mask);
 315
 316         for (;;) {
 317                 struct crypto_alg *alg;
 318
 319                 alg = crypto_lookup_skcipher(alg_name, type, mask);
 320                 if (IS_ERR(alg)) {
 321                         err = PTR_ERR(alg);
 322                         goto err;
 323                 }
 324
 325                 tfm = __crypto_alloc_tfm(alg, type, mask);
 326                 if (!IS_ERR(tfm))
 327                         return __crypto_ablkcipher_cast(tfm);
 328
 329                 crypto_mod_put(alg);
 330                 err = PTR_ERR(tfm);
 331
 332 err:
 333                 if (err != -EAGAIN)
 334                         break;
 335                 if (signal_pending(current)) {
 336                         err = -EINTR;
 337                         break;
 338                 }
 339         }
 340
 341         return ERR_PTR(err);
 342 }
 343 EXPORT_SYMBOL_GPL(crypto_alloc_ablkcipher);