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/kernel.h>
  15 #include <linux/module.h>
  16 #include <linux/sched.h>
  17
  18 static int crypto_arc4_setkey(struct crypto_skcipher *tfm, const u8 *in_key,
  19                               unsigned int key_len)
  20 {
  21         struct arc4_ctx *ctx = crypto_skcipher_ctx(tfm);
  22
  23         return arc4_setkey(ctx, in_key, key_len);
  24 }
  25
  26 static int crypto_arc4_crypt(struct skcipher_request *req)
  27 {
  28         struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
  29         struct arc4_ctx *ctx = crypto_skcipher_ctx(tfm);
  30         struct skcipher_walk walk;
  31         int err;
  32
  33         err = skcipher_walk_virt(&walk, req, false);
  34
  35         while (walk.nbytes > 0) {
  36                 arc4_crypt(ctx, walk.dst.virt.addr, walk.src.virt.addr,
  37                            walk.nbytes);
  38                 err = skcipher_walk_done(&walk, 0);
  39         }
  40
  41         return err;
  42 }
  43
  44 static int crypto_arc4_init(struct crypto_skcipher *tfm)
  45 {
  46         pr_warn_ratelimited("\"%s\" (%ld) uses obsolete ecb(arc4) skcipher\n",
  47                             current->comm, (unsigned long)current->pid);
  48
  49         return 0;
  50 }
  51
  52 static struct skcipher_alg arc4_alg = {
  53         /*
  54          * For legacy reasons, this is named "ecb(arc4)", not "arc4".
  55          * Nevertheless it's actually a stream cipher, not a block cipher.
  56          */
  57         .base.cra_name          =       "ecb(arc4)",
  58         .base.cra_driver_name   =       "ecb(arc4)-generic",
  59         .base.cra_priority      =       100,
  60         .base.cra_blocksize     =       ARC4_BLOCK_SIZE,
  61         .base.cra_ctxsize       =       sizeof(struct arc4_ctx),
  62         .base.cra_module        =       THIS_MODULE,
  63         .min_keysize            =       ARC4_MIN_KEY_SIZE,
  64         .max_keysize            =       ARC4_MAX_KEY_SIZE,
  65         .setkey                 =       crypto_arc4_setkey,
  66         .encrypt                =       crypto_arc4_crypt,
  67         .decrypt                =       crypto_arc4_crypt,
  68         .init                   =       crypto_arc4_init,
  69 };
  70
  71 static int __init arc4_init(void)
  72 {
  73         return crypto_register_skcipher(&arc4_alg);
  74 }
  75
  76 static void __exit arc4_exit(void)
  77 {
  78         crypto_unregister_skcipher(&arc4_alg);
  79 }
  80
  81 subsys_initcall(arc4_init);
  82 module_exit(arc4_exit);
  83
  84 MODULE_LICENSE("GPL");
  85 MODULE_DESCRIPTION("ARC4 Cipher Algorithm");
  86 MODULE_AUTHOR("Jon Oberheide <jon@oberheide.org>");
  87 MODULE_ALIAS_CRYPTO("ecb(arc4)");