92 lines
2.6 KiB
C
92 lines
2.6 KiB
C
/*
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* Glue code for optimized assembly version of Salsa20.
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*
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* Copyright (c) 2007 Tan Swee Heng <thesweeheng@gmail.com>
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*
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* The assembly codes are public domain assembly codes written by Daniel. J.
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* Bernstein <djb@cr.yp.to>. The codes are modified to include indentation
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* and to remove extraneous comments and functions that are not needed.
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* - i586 version, renamed as salsa20-i586-asm_32.S
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* available from <http://cr.yp.to/snuffle/salsa20/x86-pm/salsa20.s>
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* - x86-64 version, renamed as salsa20-x86_64-asm_64.S
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* available from <http://cr.yp.to/snuffle/salsa20/amd64-3/salsa20.s>
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*
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* Also modified to set up the initial state using the generic C code rather
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* than in assembly.
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the Free
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* Software Foundation; either version 2 of the License, or (at your option)
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* any later version.
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*
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*/
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#include <asm/unaligned.h>
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#include <crypto/internal/skcipher.h>
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#include <crypto/salsa20.h>
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#include <linux/module.h>
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asmlinkage void salsa20_encrypt_bytes(u32 state[16], const u8 *src, u8 *dst,
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u32 bytes);
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static int salsa20_asm_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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const struct salsa20_ctx *ctx = crypto_skcipher_ctx(tfm);
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struct skcipher_walk walk;
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u32 state[16];
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int err;
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err = skcipher_walk_virt(&walk, req, true);
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crypto_salsa20_init(state, ctx, walk.iv);
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while (walk.nbytes > 0) {
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unsigned int nbytes = walk.nbytes;
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if (nbytes < walk.total)
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nbytes = round_down(nbytes, walk.stride);
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salsa20_encrypt_bytes(state, walk.src.virt.addr,
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walk.dst.virt.addr, nbytes);
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err = skcipher_walk_done(&walk, walk.nbytes - nbytes);
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}
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return err;
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}
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static struct skcipher_alg alg = {
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.base.cra_name = "salsa20",
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.base.cra_driver_name = "salsa20-asm",
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.base.cra_priority = 200,
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.base.cra_blocksize = 1,
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.base.cra_ctxsize = sizeof(struct salsa20_ctx),
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.base.cra_module = THIS_MODULE,
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.min_keysize = SALSA20_MIN_KEY_SIZE,
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.max_keysize = SALSA20_MAX_KEY_SIZE,
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.ivsize = SALSA20_IV_SIZE,
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.chunksize = SALSA20_BLOCK_SIZE,
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.setkey = crypto_salsa20_setkey,
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.encrypt = salsa20_asm_crypt,
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.decrypt = salsa20_asm_crypt,
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};
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static int __init init(void)
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{
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return crypto_register_skcipher(&alg);
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}
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static void __exit fini(void)
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{
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crypto_unregister_skcipher(&alg);
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}
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module_init(init);
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module_exit(fini);
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MODULE_LICENSE("GPL");
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MODULE_DESCRIPTION ("Salsa20 stream cipher algorithm (optimized assembly version)");
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MODULE_ALIAS_CRYPTO("salsa20");
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MODULE_ALIAS_CRYPTO("salsa20-asm");
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