linux/crypto/ecb.c
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   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
  21struct crypto_ecb_ctx {
  22        struct crypto_cipher *child;
  23};
  24
  25static 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
  41static 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
  69static 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
  83static 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
  97static 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
 103        tfm = crypto_spawn_tfm(spawn);
 104        if (IS_ERR(tfm))
 105                return PTR_ERR(tfm);
 106
 107        ctx->child = crypto_cipher_cast(tfm);
 108        return 0;
 109}
 110
 111static void crypto_ecb_exit_tfm(struct crypto_tfm *tfm)
 112{
 113        struct crypto_ecb_ctx *ctx = crypto_tfm_ctx(tfm);
 114        crypto_free_cipher(ctx->child);
 115}
 116
 117static struct crypto_instance *crypto_ecb_alloc(void *param, unsigned int len)
 118{
 119        struct crypto_instance *inst;
 120        struct crypto_alg *alg;
 121
 122        alg = crypto_get_attr_alg(param, len, CRYPTO_ALG_TYPE_CIPHER,
 123                                  CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_ASYNC);
 124        if (IS_ERR(alg))
 125                return ERR_PTR(PTR_ERR(alg));
 126
 127        inst = crypto_alloc_instance("ecb", alg);
 128        if (IS_ERR(inst))
 129                goto out_put_alg;
 130
 131        inst->alg.cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER;
 132        inst->alg.cra_priority = alg->cra_priority;
 133        inst->alg.cra_blocksize = alg->cra_blocksize;
 134        inst->alg.cra_alignmask = alg->cra_alignmask;
 135        inst->alg.cra_type = &crypto_blkcipher_type;
 136
 137        inst->alg.cra_blkcipher.min_keysize = alg->cra_cipher.cia_min_keysize;
 138        inst->alg.cra_blkcipher.max_keysize = alg->cra_cipher.cia_max_keysize;
 139
 140        inst->alg.cra_ctxsize = sizeof(struct crypto_ecb_ctx);
 141
 142        inst->alg.cra_init = crypto_ecb_init_tfm;
 143        inst->alg.cra_exit = crypto_ecb_exit_tfm;
 144
 145        inst->alg.cra_blkcipher.setkey = crypto_ecb_setkey;
 146        inst->alg.cra_blkcipher.encrypt = crypto_ecb_encrypt;
 147        inst->alg.cra_blkcipher.decrypt = crypto_ecb_decrypt;
 148
 149out_put_alg:
 150        crypto_mod_put(alg);
 151        return inst;
 152}
 153
 154static void crypto_ecb_free(struct crypto_instance *inst)
 155{
 156        crypto_drop_spawn(crypto_instance_ctx(inst));
 157        kfree(inst);
 158}
 159
 160static struct crypto_template crypto_ecb_tmpl = {
 161        .name = "ecb",
 162        .alloc = crypto_ecb_alloc,
 163        .free = crypto_ecb_free,
 164        .module = THIS_MODULE,
 165};
 166
 167static int __init crypto_ecb_module_init(void)
 168{
 169        return crypto_register_template(&crypto_ecb_tmpl);
 170}
 171
 172static void __exit crypto_ecb_module_exit(void)
 173{
 174        crypto_unregister_template(&crypto_ecb_tmpl);
 175}
 176
 177module_init(crypto_ecb_module_init);
 178module_exit(crypto_ecb_module_exit);
 179
 180MODULE_LICENSE("GPL");
 181MODULE_DESCRIPTION("ECB block cipher algorithm");
 182
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