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