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)"); 88