![Thomas Gleixner](/assets/img/avatar_default.png)
Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license as published by the free software foundation either version 2 of the license or at your option any later version extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 3029 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Allison Randal <allison@lohutok.net> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
168 lines
3.3 KiB
C
168 lines
3.3 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* Cryptographic API
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*
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* ARC4 Cipher Algorithm
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*
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* Jon Oberheide <jon@oberheide.org>
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*/
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#include <crypto/algapi.h>
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#include <crypto/arc4.h>
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#include <crypto/internal/skcipher.h>
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#include <linux/init.h>
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#include <linux/module.h>
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struct arc4_ctx {
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u32 S[256];
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u32 x, y;
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};
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static int arc4_set_key(struct crypto_tfm *tfm, const u8 *in_key,
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unsigned int key_len)
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{
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struct arc4_ctx *ctx = crypto_tfm_ctx(tfm);
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int i, j = 0, k = 0;
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ctx->x = 1;
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ctx->y = 0;
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for (i = 0; i < 256; i++)
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ctx->S[i] = i;
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for (i = 0; i < 256; i++) {
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u32 a = ctx->S[i];
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j = (j + in_key[k] + a) & 0xff;
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ctx->S[i] = ctx->S[j];
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ctx->S[j] = a;
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if (++k >= key_len)
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k = 0;
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}
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return 0;
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}
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static int arc4_set_key_skcipher(struct crypto_skcipher *tfm, const u8 *in_key,
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unsigned int key_len)
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{
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return arc4_set_key(&tfm->base, in_key, key_len);
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}
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static void arc4_crypt(struct arc4_ctx *ctx, u8 *out, const u8 *in,
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unsigned int len)
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{
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u32 *const S = ctx->S;
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u32 x, y, a, b;
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u32 ty, ta, tb;
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if (len == 0)
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return;
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x = ctx->x;
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y = ctx->y;
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a = S[x];
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y = (y + a) & 0xff;
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b = S[y];
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do {
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S[y] = a;
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a = (a + b) & 0xff;
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S[x] = b;
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x = (x + 1) & 0xff;
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ta = S[x];
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ty = (y + ta) & 0xff;
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tb = S[ty];
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*out++ = *in++ ^ S[a];
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if (--len == 0)
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break;
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y = ty;
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a = ta;
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b = tb;
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} while (true);
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ctx->x = x;
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ctx->y = y;
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}
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static void arc4_crypt_one(struct crypto_tfm *tfm, u8 *out, const u8 *in)
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{
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arc4_crypt(crypto_tfm_ctx(tfm), out, in, 1);
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}
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static int ecb_arc4_crypt(struct skcipher_request *req)
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{
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struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
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struct arc4_ctx *ctx = crypto_skcipher_ctx(tfm);
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struct skcipher_walk walk;
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int err;
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err = skcipher_walk_virt(&walk, req, false);
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while (walk.nbytes > 0) {
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arc4_crypt(ctx, walk.dst.virt.addr, walk.src.virt.addr,
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walk.nbytes);
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err = skcipher_walk_done(&walk, 0);
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}
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return err;
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}
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static struct crypto_alg arc4_cipher = {
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.cra_name = "arc4",
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.cra_flags = CRYPTO_ALG_TYPE_CIPHER,
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.cra_blocksize = ARC4_BLOCK_SIZE,
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.cra_ctxsize = sizeof(struct arc4_ctx),
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.cra_module = THIS_MODULE,
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.cra_u = {
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.cipher = {
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.cia_min_keysize = ARC4_MIN_KEY_SIZE,
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.cia_max_keysize = ARC4_MAX_KEY_SIZE,
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.cia_setkey = arc4_set_key,
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.cia_encrypt = arc4_crypt_one,
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.cia_decrypt = arc4_crypt_one,
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},
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},
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};
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static struct skcipher_alg arc4_skcipher = {
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.base.cra_name = "ecb(arc4)",
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.base.cra_priority = 100,
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.base.cra_blocksize = ARC4_BLOCK_SIZE,
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.base.cra_ctxsize = sizeof(struct arc4_ctx),
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.base.cra_module = THIS_MODULE,
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.min_keysize = ARC4_MIN_KEY_SIZE,
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.max_keysize = ARC4_MAX_KEY_SIZE,
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.setkey = arc4_set_key_skcipher,
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.encrypt = ecb_arc4_crypt,
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.decrypt = ecb_arc4_crypt,
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};
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static int __init arc4_init(void)
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{
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int err;
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err = crypto_register_alg(&arc4_cipher);
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if (err)
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return err;
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err = crypto_register_skcipher(&arc4_skcipher);
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if (err)
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crypto_unregister_alg(&arc4_cipher);
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return err;
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}
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static void __exit arc4_exit(void)
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{
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crypto_unregister_alg(&arc4_cipher);
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crypto_unregister_skcipher(&arc4_skcipher);
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}
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subsys_initcall(arc4_init);
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module_exit(arc4_exit);
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MODULE_LICENSE("GPL");
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MODULE_DESCRIPTION("ARC4 Cipher Algorithm");
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MODULE_AUTHOR("Jon Oberheide <jon@oberheide.org>");
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MODULE_ALIAS_CRYPTO("arc4");
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