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)"); 77