/* * Glue code for optimized assembly version of Salsa20. * * Copyright (c) 2007 Tan Swee Heng <thesweeheng@gmail.com> * * The assembly codes are public domain assembly codes written by Daniel. J. * Bernstein <djb@cr.yp.to>. The codes are modified to include indentation * and to remove extraneous comments and functions that are not needed. * - i586 version, renamed as salsa20-i586-asm_32.S * available from <http://cr.yp.to/snuffle/salsa20/x86-pm/salsa20.s> * - x86-64 version, renamed as salsa20-x86_64-asm_64.S * available from <http://cr.yp.to/snuffle/salsa20/amd64-3/salsa20.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. * */ #include <crypto/algapi.h> #include <linux/module.h> #include <linux/crypto.h> #define SALSA20_IV_SIZE 8U #define SALSA20_MIN_KEY_SIZE 16U #define SALSA20_MAX_KEY_SIZE 32U // use the ECRYPT_* function names #define salsa20_keysetup ECRYPT_keysetup #define salsa20_ivsetup ECRYPT_ivsetup #define salsa20_encrypt_bytes ECRYPT_encrypt_bytes struct salsa20_ctx { u32 input[16]; }; asmlinkage void salsa20_keysetup(struct salsa20_ctx *ctx, const u8 *k, u32 keysize, u32 ivsize); asmlinkage void salsa20_ivsetup(struct salsa20_ctx *ctx, const u8 *iv); asmlinkage void salsa20_encrypt_bytes(struct salsa20_ctx *ctx, const u8 *src, u8 *dst, u32 bytes); static int setkey(struct crypto_tfm *tfm, const u8 *key, unsigned int keysize) { struct salsa20_ctx *ctx = crypto_tfm_ctx(tfm); salsa20_keysetup(ctx, key, keysize*8, SALSA20_IV_SIZE*8); return 0; } static int encrypt(struct blkcipher_desc *desc, struct scatterlist *dst, struct scatterlist *src, unsigned int nbytes) { struct blkcipher_walk walk; struct crypto_blkcipher *tfm = desc->tfm; struct salsa20_ctx *ctx = crypto_blkcipher_ctx(tfm); int err; blkcipher_walk_init(&walk, dst, src, nbytes); err = blkcipher_walk_virt_block(desc, &walk, 64); salsa20_ivsetup(ctx, walk.iv); if (likely(walk.nbytes == nbytes)) { salsa20_encrypt_bytes(ctx, walk.src.virt.addr, walk.dst.virt.addr, nbytes); return blkcipher_walk_done(desc, &walk, 0); } while (walk.nbytes >= 64) { salsa20_encrypt_bytes(ctx, walk.src.virt.addr, walk.dst.virt.addr, walk.nbytes - (walk.nbytes % 64)); err = blkcipher_walk_done(desc, &walk, walk.nbytes % 64); } if (walk.nbytes) { salsa20_encrypt_bytes(ctx, walk.src.virt.addr, walk.dst.virt.addr, walk.nbytes); err = blkcipher_walk_done(desc, &walk, 0); } return err; } static struct crypto_alg alg = { .cra_name = "salsa20", .cra_driver_name = "salsa20-asm", .cra_priority = 200, .cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER, .cra_type = &crypto_blkcipher_type, .cra_blocksize = 1, .cra_ctxsize = sizeof(struct salsa20_ctx), .cra_alignmask = 3, .cra_module = THIS_MODULE, .cra_list = LIST_HEAD_INIT(alg.cra_list), .cra_u = { .blkcipher = { .setkey = setkey, .encrypt = encrypt, .decrypt = encrypt, .min_keysize = SALSA20_MIN_KEY_SIZE, .max_keysize = SALSA20_MAX_KEY_SIZE, .ivsize = SALSA20_IV_SIZE, } } }; static int __init init(void) { return crypto_register_alg(&alg); } static void __exit fini(void) { crypto_unregister_alg(&alg); } module_init(init); module_exit(fini); MODULE_LICENSE("GPL"); MODULE_DESCRIPTION ("Salsa20 stream cipher algorithm (optimized assembly version)"); MODULE_ALIAS("salsa20"); MODULE_ALIAS("salsa20-asm");