crypto/ecb.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * ECB: Electronic CodeBook mode
   4  *
   5  * Copyright (c) 2006 Herbert Xu <herbert@gondor.apana.org.au>
   6  */
   7
   8 #include <crypto/algapi.h>
   9 #include <crypto/internal/skcipher.h>
  10 #include <linux/err.h>
  11 #include <linux/init.h>
  12 #include <linux/kernel.h>
  13 #include <linux/module.h>
  14
  15 static int crypto_ecb_crypt(struct skcipher_request *req,
  16                             struct crypto_cipher *cipher,
  17                             void (*fn)(struct crypto_tfm *, u8 *, const u8 *))
  18 {
  19         const unsigned int bsize = crypto_cipher_blocksize(cipher);
  20         struct skcipher_walk walk;
  21         unsigned int nbytes;
  22         int err;
  23
  24         err = skcipher_walk_virt(&walk, req, false);
  25
  26         while ((nbytes = walk.nbytes) != 0) {
  27                 const u8 *src = walk.src.virt.addr;
  28                 u8 *dst = walk.dst.virt.addr;
  29
  30                 do {
  31                         fn(crypto_cipher_tfm(cipher), dst, src);
  32
  33                         src += bsize;
  34                         dst += bsize;
  35                 } while ((nbytes -= bsize) >= bsize);
  36
  37                 err = skcipher_walk_done(&walk, nbytes);
  38         }
  39
  40         return err;
  41 }
  42
  43 static int crypto_ecb_encrypt(struct skcipher_request *req)
  44 {
  45         struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
  46         struct crypto_cipher *cipher = skcipher_cipher_simple(tfm);
  47
  48         return crypto_ecb_crypt(req, cipher,
  49                                 crypto_cipher_alg(cipher)->cia_encrypt);
  50 }
  51
  52 static int crypto_ecb_decrypt(struct skcipher_request *req)
  53 {
  54         struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
  55         struct crypto_cipher *cipher = skcipher_cipher_simple(tfm);
  56
  57         return crypto_ecb_crypt(req, cipher,
  58                                 crypto_cipher_alg(cipher)->cia_decrypt);
  59 }
  60
  61 static int crypto_ecb_create(struct crypto_template *tmpl, struct rtattr **tb)
  62 {
  63         struct skcipher_instance *inst;
  64         int err;
  65
  66         inst = skcipher_alloc_instance_simple(tmpl, tb);
  67         if (IS_ERR(inst))
  68                 return PTR_ERR(inst);
  69
  70         inst->alg.ivsize = 0; /* ECB mode doesn't take an IV */
  71
  72         inst->alg.encrypt = crypto_ecb_encrypt;
  73         inst->alg.decrypt = crypto_ecb_decrypt;
  74
  75         err = skcipher_register_instance(tmpl, inst);
  76         if (err)
  77                 inst->free(inst);
  78
  79         return err;
  80 }
  81
  82 static struct crypto_template crypto_ecb_tmpl = {
  83         .name = "ecb",
  84         .create = crypto_ecb_create,
  85         .module = THIS_MODULE,
  86 };
  87
  88 static int __init crypto_ecb_module_init(void)
  89 {
  90         return crypto_register_template(&crypto_ecb_tmpl);
  91 }
  92
  93 static void __exit crypto_ecb_module_exit(void)
  94 {
  95         crypto_unregister_template(&crypto_ecb_tmpl);
  96 }
  97
  98 subsys_initcall(crypto_ecb_module_init);
  99 module_exit(crypto_ecb_module_exit);
 100
 101 MODULE_LICENSE("GPL");
 102 MODULE_DESCRIPTION("ECB block cipher mode of operation");
 103 MODULE_ALIAS_CRYPTO("ecb");