6c2bb98bc3
Up until now algorithms have been happy to get a context pointer since they know everything that's in the tfm already (e.g., alignment, block size). However, once we have parameterised algorithms, such information will be specific to each tfm. So the algorithm API needs to be changed to pass the tfm structure instead of the context pointer. This patch is basically a text substitution. The only tricky bit is the assembly routines that need to get the context pointer offset through asm-offsets.h. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
104 lines
2.1 KiB
C
104 lines
2.1 KiB
C
/*
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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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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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*/
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/crypto.h>
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#define ARC4_MIN_KEY_SIZE 1
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#define ARC4_MAX_KEY_SIZE 256
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#define ARC4_BLOCK_SIZE 1
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struct arc4_ctx {
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u8 S[256];
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u8 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, u32 *flags)
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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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{
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u8 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 void arc4_crypt(struct crypto_tfm *tfm, u8 *out, const u8 *in)
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{
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struct arc4_ctx *ctx = crypto_tfm_ctx(tfm);
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u8 *const S = ctx->S;
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u8 x = ctx->x;
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u8 y = ctx->y;
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u8 a, b;
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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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S[x] = b;
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S[y] = a;
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x = (x + 1) & 0xff;
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*out++ = *in ^ S[(a + b) & 0xff];
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ctx->x = x;
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ctx->y = y;
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}
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static struct crypto_alg arc4_alg = {
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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_list = LIST_HEAD_INIT(arc4_alg.cra_list),
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.cra_u = { .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,
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.cia_decrypt = arc4_crypt } }
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};
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static int __init arc4_init(void)
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{
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return crypto_register_alg(&arc4_alg);
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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_alg);
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}
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module_init(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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