the-tree/crypto/arc4.c

0001 // SPDX-License-Identifier: GPL-2.0-or-later
0002 /*
0003  * Cryptographic API
0004  *
0005  * ARC4 Cipher Algorithm
0006  *
0007  * Jon Oberheide <jon@oberheide.org>
0008  */
0009
0010 #include <crypto/algapi.h>
0011 #include <crypto/arc4.h>
0012 #include <crypto/internal/skcipher.h>
0013 #include <linux/init.h>
0014 #include <linux/kernel.h>
0015 #include <linux/module.h>
0016 #include <linux/sched.h>
0017
0018 static int crypto_arc4_setkey(struct crypto_skcipher *tfm, const u8 *in_key,
0019                   unsigned int key_len)
0020 {
0021     struct arc4_ctx *ctx = crypto_skcipher_ctx(tfm);
0022
0023     return arc4_setkey(ctx, in_key, key_len);
0024 }
0025
0026 static int crypto_arc4_crypt(struct skcipher_request *req)
0027 {
0028     struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
0029     struct arc4_ctx *ctx = crypto_skcipher_ctx(tfm);
0030     struct skcipher_walk walk;
0031     int err;
0032
0033     err = skcipher_walk_virt(&walk, req, false);
0034
0035     while (walk.nbytes > 0) {
0036         arc4_crypt(ctx, walk.dst.virt.addr, walk.src.virt.addr,
0037                walk.nbytes);
0038         err = skcipher_walk_done(&walk, 0);
0039     }
0040
0041     return err;
0042 }
0043
0044 static int crypto_arc4_init(struct crypto_skcipher *tfm)
0045 {
0046     pr_warn_ratelimited("\"%s\" (%ld) uses obsolete ecb(arc4) skcipher\n",
0047                 current->comm, (unsigned long)current->pid);
0048
0049     return 0;
0050 }
0051
0052 static struct skcipher_alg arc4_alg = {
0053     /*
0054      * For legacy reasons, this is named "ecb(arc4)", not "arc4".
0055      * Nevertheless it's actually a stream cipher, not a block cipher.
0056      */
0057     .base.cra_name      =   "ecb(arc4)",
0058     .base.cra_driver_name   =   "ecb(arc4)-generic",
0059     .base.cra_priority  =   100,
0060     .base.cra_blocksize =   ARC4_BLOCK_SIZE,
0061     .base.cra_ctxsize   =   sizeof(struct arc4_ctx),
0062     .base.cra_module    =   THIS_MODULE,
0063     .min_keysize        =   ARC4_MIN_KEY_SIZE,
0064     .max_keysize        =   ARC4_MAX_KEY_SIZE,
0065     .setkey         =   crypto_arc4_setkey,
0066     .encrypt        =   crypto_arc4_crypt,
0067     .decrypt        =   crypto_arc4_crypt,
0068     .init           =   crypto_arc4_init,
0069 };
0070
0071 static int __init arc4_init(void)
0072 {
0073     return crypto_register_skcipher(&arc4_alg);
0074 }
0075
0076 static void __exit arc4_exit(void)
0077 {
0078     crypto_unregister_skcipher(&arc4_alg);
0079 }
0080
0081 subsys_initcall(arc4_init);
0082 module_exit(arc4_exit);
0083
0084 MODULE_LICENSE("GPL");
0085 MODULE_DESCRIPTION("ARC4 Cipher Algorithm");
0086 MODULE_AUTHOR("Jon Oberheide <jon@oberheide.org>");
0087 MODULE_ALIAS_CRYPTO("ecb(arc4)");