crypto/ecb.c

   1 /*
   2  * ECB: Electronic CodeBook mode
   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 <crypto/algapi.h>
  14 #include <linux/err.h>
  15 #include <linux/init.h>
  16 #include <linux/kernel.h>
  17 #include <linux/module.h>
  18 #include <linux/scatterlist.h>
  19 #include <linux/slab.h>
  20
  21 struct crypto_ecb_ctx {
  22         struct crypto_cipher *child;
  23 };
  24
  25 static int crypto_ecb_setkey(struct crypto_tfm *parent, const u8 *key,
  26                              unsigned int keylen)
  27 {
  28         struct crypto_ecb_ctx *ctx = crypto_tfm_ctx(parent);
  29         struct crypto_cipher *child = ctx->child;
  30         int err;
  31
  32         crypto_cipher_clear_flags(child, CRYPTO_TFM_REQ_MASK);
  33         crypto_cipher_set_flags(child, crypto_tfm_get_flags(parent) &
  34                                        CRYPTO_TFM_REQ_MASK);
  35         err = crypto_cipher_setkey(child, key, keylen);
  36         crypto_tfm_set_flags(parent, crypto_cipher_get_flags(child) &
  37                                      CRYPTO_TFM_RES_MASK);
  38         return err;
  39 }
  40
  41 static int crypto_ecb_crypt(struct blkcipher_desc *desc,
  42                             struct blkcipher_walk *walk,
  43                             struct crypto_cipher *tfm,
  44                             void (*fn)(struct crypto_tfm *, u8 *, const u8 *))
  45 {
  46         int bsize = crypto_cipher_blocksize(tfm);
  47         unsigned int nbytes;
  48         int err;
  49
  50         err = blkcipher_walk_virt(desc, walk);
  51
  52         while ((nbytes = walk->nbytes)) {
  53                 u8 *wsrc = walk->src.virt.addr;
  54                 u8 *wdst = walk->dst.virt.addr;
  55
  56                 do {
  57                         fn(crypto_cipher_tfm(tfm), wdst, wsrc);
  58
  59                         wsrc += bsize;
  60                         wdst += bsize;
  61                 } while ((nbytes -= bsize) >= bsize);
  62
  63                 err = blkcipher_walk_done(desc, walk, nbytes);
  64         }
  65
  66         return err;
  67 }
  68
  69 static int crypto_ecb_encrypt(struct blkcipher_desc *desc,
  70                               struct scatterlist *dst, struct scatterlist *src,
  71                               unsigned int nbytes)
  72 {
  73         struct blkcipher_walk walk;
  74         struct crypto_blkcipher *tfm = desc->tfm;
  75         struct crypto_ecb_ctx *ctx = crypto_blkcipher_ctx(tfm);
  76         struct crypto_cipher *child = ctx->child;
  77
  78         blkcipher_walk_init(&walk, dst, src, nbytes);
  79         return crypto_ecb_crypt(desc, &walk, child,
  80                                 crypto_cipher_alg(child)->cia_encrypt);
  81 }
  82
  83 static int crypto_ecb_decrypt(struct blkcipher_desc *desc,
  84                               struct scatterlist *dst, struct scatterlist *src,
  85                               unsigned int nbytes)
  86 {
  87         struct blkcipher_walk walk;
  88         struct crypto_blkcipher *tfm = desc->tfm;
  89         struct crypto_ecb_ctx *ctx = crypto_blkcipher_ctx(tfm);
  90         struct crypto_cipher *child = ctx->child;
  91
  92         blkcipher_walk_init(&walk, dst, src, nbytes);
  93         return crypto_ecb_crypt(desc, &walk, child,
  94                                 crypto_cipher_alg(child)->cia_decrypt);
  95 }
  96
  97 static int crypto_ecb_init_tfm(struct crypto_tfm *tfm)
  98 {
  99         struct crypto_instance *inst = (void *)tfm->__crt_alg;
 100         struct crypto_spawn *spawn = crypto_instance_ctx(inst);
 101         struct crypto_ecb_ctx *ctx = crypto_tfm_ctx(tfm);
 102         struct crypto_cipher *cipher;
 103
 104         cipher = crypto_spawn_cipher(spawn);
 105         if (IS_ERR(cipher))
 106                 return PTR_ERR(cipher);
 107
 108         ctx->child = cipher;
 109         return 0;
 110 }
 111
 112 static void crypto_ecb_exit_tfm(struct crypto_tfm *tfm)
 113 {
 114         struct crypto_ecb_ctx *ctx = crypto_tfm_ctx(tfm);
 115         crypto_free_cipher(ctx->child);
 116 }
 117
 118 static struct crypto_instance *crypto_ecb_alloc(struct rtattr **tb)
 119 {
 120         struct crypto_instance *inst;
 121         struct crypto_alg *alg;
 122         int err;
 123
 124         err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_BLKCIPHER);
 125         if (err)
 126                 return ERR_PTR(err);
 127
 128         alg = crypto_get_attr_alg(tb, CRYPTO_ALG_TYPE_CIPHER,
 129                                   CRYPTO_ALG_TYPE_MASK);
 130         if (IS_ERR(alg))
 131                 return ERR_CAST(alg);
 132
 133         inst = crypto_alloc_instance("ecb", alg);
 134         if (IS_ERR(inst))
 135                 goto out_put_alg;
 136
 137         inst->alg.cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER;
 138         inst->alg.cra_priority = alg->cra_priority;
 139         inst->alg.cra_blocksize = alg->cra_blocksize;
 140         inst->alg.cra_alignmask = alg->cra_alignmask;
 141         inst->alg.cra_type = &crypto_blkcipher_type;
 142
 143         inst->alg.cra_blkcipher.min_keysize = alg->cra_cipher.cia_min_keysize;
 144         inst->alg.cra_blkcipher.max_keysize = alg->cra_cipher.cia_max_keysize;
 145
 146         inst->alg.cra_ctxsize = sizeof(struct crypto_ecb_ctx);
 147
 148         inst->alg.cra_init = crypto_ecb_init_tfm;
 149         inst->alg.cra_exit = crypto_ecb_exit_tfm;
 150
 151         inst->alg.cra_blkcipher.setkey = crypto_ecb_setkey;
 152         inst->alg.cra_blkcipher.encrypt = crypto_ecb_encrypt;
 153         inst->alg.cra_blkcipher.decrypt = crypto_ecb_decrypt;
 154
 155 out_put_alg:
 156         crypto_mod_put(alg);
 157         return inst;
 158 }
 159
 160 static void crypto_ecb_free(struct crypto_instance *inst)
 161 {
 162         crypto_drop_spawn(crypto_instance_ctx(inst));
 163         kfree(inst);
 164 }
 165
 166 static struct crypto_template crypto_ecb_tmpl = {
 167         .name = "ecb",
 168         .alloc = crypto_ecb_alloc,
 169         .free = crypto_ecb_free,
 170         .module = THIS_MODULE,
 171 };
 172
 173 static int __init crypto_ecb_module_init(void)
 174 {
 175         return crypto_register_template(&crypto_ecb_tmpl);
 176 }
 177
 178 static void __exit crypto_ecb_module_exit(void)
 179 {
 180         crypto_unregister_template(&crypto_ecb_tmpl);
 181 }
 182
 183 module_init(crypto_ecb_module_init);
 184 module_exit(crypto_ecb_module_exit);
 185
 186 MODULE_LICENSE("GPL");
 187 MODULE_DESCRIPTION("ECB block cipher algorithm");