crypto/arc4.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Cryptographic API
   4  *
   5  * ARC4 Cipher Algorithm
   6  *
   7  * Jon Oberheide <jon@oberheide.org>
   8  */
   9
  10 #include <crypto/algapi.h>
  11 #include <crypto/arc4.h>
  12 #include <crypto/internal/skcipher.h>
  13 #include <linux/init.h>
  14 #include <linux/module.h>
  15
  16 static int crypto_arc4_setkey(struct crypto_skcipher *tfm, const u8 *in_key,
  17                               unsigned int key_len)
  18 {
  19         struct arc4_ctx *ctx = crypto_skcipher_ctx(tfm);
  20
  21         return arc4_setkey(ctx, in_key, key_len);
  22 }
  23
  24 static int crypto_arc4_crypt(struct skcipher_request *req)
  25 {
  26         struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
  27         struct arc4_ctx *ctx = crypto_skcipher_ctx(tfm);
  28         struct skcipher_walk walk;
  29         int err;
  30
  31         err = skcipher_walk_virt(&walk, req, false);
  32
  33         while (walk.nbytes > 0) {
  34                 arc4_crypt(ctx, walk.dst.virt.addr, walk.src.virt.addr,
  35                            walk.nbytes);
  36                 err = skcipher_walk_done(&walk, 0);
  37         }
  38
  39         return err;
  40 }
  41
  42 static struct skcipher_alg arc4_alg = {
  43         /*
  44          * For legacy reasons, this is named "ecb(arc4)", not "arc4".
  45          * Nevertheless it's actually a stream cipher, not a block cipher.
  46          */
  47         .base.cra_name          =       "ecb(arc4)",
  48         .base.cra_driver_name   =       "ecb(arc4)-generic",
  49         .base.cra_priority      =       100,
  50         .base.cra_blocksize     =       ARC4_BLOCK_SIZE,
  51         .base.cra_ctxsize       =       sizeof(struct arc4_ctx),
  52         .base.cra_module        =       THIS_MODULE,
  53         .min_keysize            =       ARC4_MIN_KEY_SIZE,
  54         .max_keysize            =       ARC4_MAX_KEY_SIZE,
  55         .setkey                 =       crypto_arc4_setkey,
  56         .encrypt                =       crypto_arc4_crypt,
  57         .decrypt                =       crypto_arc4_crypt,
  58 };
  59
  60 static int __init arc4_init(void)
  61 {
  62         return crypto_register_skcipher(&arc4_alg);
  63 }
  64
  65 static void __exit arc4_exit(void)
  66 {
  67         crypto_unregister_skcipher(&arc4_alg);
  68 }
  69
  70 subsys_initcall(arc4_init);
  71 module_exit(arc4_exit);
  72
  73 MODULE_LICENSE("GPL");
  74 MODULE_DESCRIPTION("ARC4 Cipher Algorithm");
  75 MODULE_AUTHOR("Jon Oberheide <jon@oberheide.org>");
  76 MODULE_ALIAS_CRYPTO("ecb(arc4)");