Revision 8874e812feb4926f4a51a82c4fca75c7daa05fc5 authored by Linus Torvalds on 21 June 2012, 20:41:07 UTC, committed by Linus Torvalds on 21 June 2012, 20:41:07 UTC
Pull btrfs fixes from Chris Mason: "This is a small pull with btrfs fixes. The biggest of the bunch is another fix for the new backref walking code. We're still hammering out one btrfs dio vs buffered reads problem, but that one will have to wait for the next rc." * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs: Btrfs: delay iput with async extents Btrfs: add a missing spin_lock Btrfs: don't assume to be on the correct extent in add_all_parents Btrfs: introduce btrfs_next_old_item
arc4.c
/*
* Cryptographic API
*
* ARC4 Cipher Algorithm
*
* Jon Oberheide <jon@oberheide.org>
*
* 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.
*
*/
#include <linux/module.h>
#include <linux/init.h>
#include <linux/crypto.h>
#define ARC4_MIN_KEY_SIZE 1
#define ARC4_MAX_KEY_SIZE 256
#define ARC4_BLOCK_SIZE 1
struct arc4_ctx {
u8 S[256];
u8 x, y;
};
static int arc4_set_key(struct crypto_tfm *tfm, const u8 *in_key,
unsigned int key_len)
{
struct arc4_ctx *ctx = crypto_tfm_ctx(tfm);
int i, j = 0, k = 0;
ctx->x = 1;
ctx->y = 0;
for (i = 0; i < 256; i++)
ctx->S[i] = i;
for (i = 0; i < 256; i++) {
u8 a = ctx->S[i];
j = (j + in_key[k] + a) & 0xff;
ctx->S[i] = ctx->S[j];
ctx->S[j] = a;
if (++k >= key_len)
k = 0;
}
return 0;
}
static void arc4_crypt(struct crypto_tfm *tfm, u8 *out, const u8 *in)
{
struct arc4_ctx *ctx = crypto_tfm_ctx(tfm);
u8 *const S = ctx->S;
u8 x = ctx->x;
u8 y = ctx->y;
u8 a, b;
a = S[x];
y = (y + a) & 0xff;
b = S[y];
S[x] = b;
S[y] = a;
x = (x + 1) & 0xff;
*out++ = *in ^ S[(a + b) & 0xff];
ctx->x = x;
ctx->y = y;
}
static struct crypto_alg arc4_alg = {
.cra_name = "arc4",
.cra_flags = CRYPTO_ALG_TYPE_CIPHER,
.cra_blocksize = ARC4_BLOCK_SIZE,
.cra_ctxsize = sizeof(struct arc4_ctx),
.cra_module = THIS_MODULE,
.cra_list = LIST_HEAD_INIT(arc4_alg.cra_list),
.cra_u = { .cipher = {
.cia_min_keysize = ARC4_MIN_KEY_SIZE,
.cia_max_keysize = ARC4_MAX_KEY_SIZE,
.cia_setkey = arc4_set_key,
.cia_encrypt = arc4_crypt,
.cia_decrypt = arc4_crypt } }
};
static int __init arc4_init(void)
{
return crypto_register_alg(&arc4_alg);
}
static void __exit arc4_exit(void)
{
crypto_unregister_alg(&arc4_alg);
}
module_init(arc4_init);
module_exit(arc4_exit);
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("ARC4 Cipher Algorithm");
MODULE_AUTHOR("Jon Oberheide <jon@oberheide.org>");
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