190 lines
5.0 KiB
C
190 lines
5.0 KiB
C
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/*
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* ARM NEON accelerated ChaCha and XChaCha stream ciphers,
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* including ChaCha20 (RFC7539)
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*
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* Copyright (C) 2016 - 2017 Linaro, Ltd. <ard.biesheuvel@linaro.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 version 2 as
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* published by the Free Software Foundation.
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*
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* Based on:
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* ChaCha20 256-bit cipher algorithm, RFC7539, SIMD glue code
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*
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* Copyright (C) 2015 Martin Willi
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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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#include <crypto/algapi.h>
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#include <crypto/chacha.h>
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#include <crypto/internal/skcipher.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <asm/hwcap.h>
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#include <asm/neon.h>
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#include <asm/simd.h>
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asmlinkage void chacha_block_xor_neon(u32 *state, u8 *dst, const u8 *src,
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int nrounds);
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asmlinkage void chacha_4block_xor_neon(u32 *state, u8 *dst, const u8 *src,
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int nrounds);
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asmlinkage void hchacha_block_neon(const u32 *state, u32 *out, int nrounds);
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static void chacha_doneon(u32 *state, u8 *dst, const u8 *src,
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unsigned int bytes, int nrounds)
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{
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u8 buf[CHACHA_BLOCK_SIZE];
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while (bytes >= CHACHA_BLOCK_SIZE * 4) {
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kernel_neon_begin();
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chacha_4block_xor_neon(state, dst, src, nrounds);
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kernel_neon_end();
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bytes -= CHACHA_BLOCK_SIZE * 4;
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src += CHACHA_BLOCK_SIZE * 4;
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dst += CHACHA_BLOCK_SIZE * 4;
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state[12] += 4;
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}
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if (!bytes)
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return;
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kernel_neon_begin();
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while (bytes >= CHACHA_BLOCK_SIZE) {
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chacha_block_xor_neon(state, dst, src, nrounds);
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bytes -= CHACHA_BLOCK_SIZE;
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src += CHACHA_BLOCK_SIZE;
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dst += CHACHA_BLOCK_SIZE;
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state[12]++;
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}
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if (bytes) {
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memcpy(buf, src, bytes);
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chacha_block_xor_neon(state, buf, buf, nrounds);
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memcpy(dst, buf, bytes);
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}
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kernel_neon_end();
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}
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static int chacha_neon_stream_xor(struct skcipher_request *req,
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struct chacha_ctx *ctx, u8 *iv)
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{
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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, false);
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crypto_chacha_init(state, ctx, 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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chacha_doneon(state, walk.dst.virt.addr, walk.src.virt.addr,
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nbytes, ctx->nrounds);
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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 int chacha_neon(struct skcipher_request *req)
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{
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struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
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struct chacha_ctx *ctx = crypto_skcipher_ctx(tfm);
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if (req->cryptlen <= CHACHA_BLOCK_SIZE || !may_use_simd())
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return crypto_chacha_crypt(req);
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return chacha_neon_stream_xor(req, ctx, req->iv);
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}
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static int xchacha_neon(struct skcipher_request *req)
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{
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struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
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struct chacha_ctx *ctx = crypto_skcipher_ctx(tfm);
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struct chacha_ctx subctx;
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u32 state[16];
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u8 real_iv[16];
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if (req->cryptlen <= CHACHA_BLOCK_SIZE || !may_use_simd())
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return crypto_xchacha_crypt(req);
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crypto_chacha_init(state, ctx, req->iv);
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kernel_neon_begin();
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hchacha_block_neon(state, subctx.key, ctx->nrounds);
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kernel_neon_end();
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subctx.nrounds = ctx->nrounds;
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memcpy(&real_iv[0], req->iv + 24, 8);
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memcpy(&real_iv[8], req->iv + 16, 8);
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return chacha_neon_stream_xor(req, &subctx, real_iv);
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}
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static struct skcipher_alg algs[] = {
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{
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.base.cra_name = "chacha20",
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.base.cra_driver_name = "chacha20-neon",
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.base.cra_priority = 300,
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.base.cra_blocksize = 1,
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.base.cra_ctxsize = sizeof(struct chacha_ctx),
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.base.cra_module = THIS_MODULE,
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.min_keysize = CHACHA_KEY_SIZE,
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.max_keysize = CHACHA_KEY_SIZE,
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.ivsize = CHACHA_IV_SIZE,
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.chunksize = CHACHA_BLOCK_SIZE,
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.walksize = 4 * CHACHA_BLOCK_SIZE,
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.setkey = crypto_chacha20_setkey,
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.encrypt = chacha_neon,
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.decrypt = chacha_neon,
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}, {
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.base.cra_name = "xchacha20",
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.base.cra_driver_name = "xchacha20-neon",
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.base.cra_priority = 300,
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.base.cra_blocksize = 1,
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.base.cra_ctxsize = sizeof(struct chacha_ctx),
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.base.cra_module = THIS_MODULE,
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.min_keysize = CHACHA_KEY_SIZE,
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.max_keysize = CHACHA_KEY_SIZE,
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.ivsize = XCHACHA_IV_SIZE,
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.chunksize = CHACHA_BLOCK_SIZE,
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.walksize = 4 * CHACHA_BLOCK_SIZE,
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.setkey = crypto_chacha20_setkey,
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.encrypt = xchacha_neon,
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.decrypt = xchacha_neon,
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}
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};
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static int __init chacha_simd_mod_init(void)
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{
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if (!(elf_hwcap & HWCAP_ASIMD))
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return -ENODEV;
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return crypto_register_skciphers(algs, ARRAY_SIZE(algs));
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}
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static void __exit chacha_simd_mod_fini(void)
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{
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crypto_unregister_skciphers(algs, ARRAY_SIZE(algs));
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}
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module_init(chacha_simd_mod_init);
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module_exit(chacha_simd_mod_fini);
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MODULE_DESCRIPTION("ChaCha and XChaCha stream ciphers (NEON accelerated)");
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MODULE_AUTHOR("Ard Biesheuvel <ard.biesheuvel@linaro.org>");
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MODULE_LICENSE("GPL v2");
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MODULE_ALIAS_CRYPTO("chacha20");
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MODULE_ALIAS_CRYPTO("chacha20-neon");
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MODULE_ALIAS_CRYPTO("xchacha20");
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MODULE_ALIAS_CRYPTO("xchacha20-neon");
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