diff options
Diffstat (limited to 'arch/x86/crypto/salsa20_glue.c')
| -rw-r--r-- | arch/x86/crypto/salsa20_glue.c | 123 |
1 files changed, 123 insertions, 0 deletions
diff --git a/arch/x86/crypto/salsa20_glue.c b/arch/x86/crypto/salsa20_glue.c new file mode 100644 index 000000000..399a29d06 --- /dev/null +++ b/arch/x86/crypto/salsa20_glue.c @@ -0,0 +1,123 @@ +/* + * 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 + +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_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_CRYPTO("salsa20"); +MODULE_ALIAS_CRYPTO("salsa20-asm"); |