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// SPDX-License-Identifier: GPL-2.0
/*
* NEON-accelerated implementation of Speck128-XTS and Speck64-XTS
*
* Copyright (c) 2018 Google, Inc
*
* Note: the NIST recommendation for XTS only specifies a 128-bit block size,
* but a 64-bit version (needed for Speck64) is fairly straightforward; the math
* is just done in GF(2^64) instead of GF(2^128), with the reducing polynomial
* x^64 + x^4 + x^3 + x + 1 from the original XEX paper (Rogaway, 2004:
* "Efficient Instantiations of Tweakable Blockciphers and Refinements to Modes
* OCB and PMAC"), represented as 0x1B.
*/
#include <asm/hwcap.h>
#include <asm/neon.h>
#include <asm/simd.h>
#include <crypto/algapi.h>
#include <crypto/gf128mul.h>
#include <crypto/internal/skcipher.h>
#include <crypto/speck.h>
#include <crypto/xts.h>
#include <linux/kernel.h>
#include <linux/module.h>
/* The assembly functions only handle multiples of 128 bytes */
#define SPECK_NEON_CHUNK_SIZE 128
/* Speck128 */
struct speck128_xts_tfm_ctx {
struct speck128_tfm_ctx main_key;
struct speck128_tfm_ctx tweak_key;
};
asmlinkage void speck128_xts_encrypt_neon(const u64 *round_keys, int nrounds,
void *dst, const void *src,
unsigned int nbytes, void *tweak);
asmlinkage void speck128_xts_decrypt_neon(const u64 *round_keys, int nrounds,
void *dst, const void *src,
unsigned int nbytes, void *tweak);
typedef void (*speck128_crypt_one_t)(const struct speck128_tfm_ctx *,
u8 *, const u8 *);
typedef void (*speck128_xts_crypt_many_t)(const u64 *, int, void *,
const void *, unsigned int, void *);
static __always_inline int
__speck128_xts_crypt(struct skcipher_request *req,
speck128_crypt_one_t crypt_one,
speck128_xts_crypt_many_t crypt_many)
{
struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
const struct speck128_xts_tfm_ctx *ctx = crypto_skcipher_ctx(tfm);
struct skcipher_walk walk;
le128 tweak;
int err;
err = skcipher_walk_virt(&walk, req, true);
crypto_speck128_encrypt(&ctx->tweak_key, (u8 *)&tweak, walk.iv);
while (walk.nbytes > 0) {
unsigned int nbytes = walk.nbytes;
u8 *dst = walk.dst.virt.addr;
const u8 *src = walk.src.virt.addr;
if (nbytes >= SPECK_NEON_CHUNK_SIZE && may_use_simd()) {
unsigned int count;
count = round_down(nbytes, SPECK_NEON_CHUNK_SIZE);
kernel_neon_begin();
(*crypt_many)(ctx->main_key.round_keys,
ctx->main_key.nrounds,
dst, src, count, &tweak);
kernel_neon_end();
dst += count;
src += count;
nbytes -= count;
}
/* Handle any remainder with generic code */
while (nbytes >= sizeof(tweak)) {
le128_xor((le128 *)dst, (const le128 *)src, &tweak);
(*crypt_one)(&ctx->main_key, dst, dst);
le128_xor((le128 *)dst, (const le128 *)dst, &tweak);
gf128mul_x_ble(&tweak, &tweak);
dst += sizeof(tweak);
src += sizeof(tweak);
nbytes -= sizeof(tweak);
}
err = skcipher_walk_done(&walk, nbytes);
}
return err;
}
static int speck128_xts_encrypt(struct skcipher_request *req)
{
return __speck128_xts_crypt(req, crypto_speck128_encrypt,
speck128_xts_encrypt_neon);
}
static int speck128_xts_decrypt(struct skcipher_request *req)
{
return __speck128_xts_crypt(req, crypto_speck128_decrypt,
speck128_xts_decrypt_neon);
}
static int speck128_xts_setkey(struct crypto_skcipher *tfm, const u8 *key,
unsigned int keylen)
{
struct speck128_xts_tfm_ctx *ctx = crypto_skcipher_ctx(tfm);
int err;
err = xts_verify_key(tfm, key, keylen);
if (err)
return err;
keylen /= 2;
err = crypto_speck128_setkey(&ctx->main_key, key, keylen);
if (err)
return err;
return crypto_speck128_setkey(&ctx->tweak_key, key + keylen, keylen);
}
/* Speck64 */
struct speck64_xts_tfm_ctx {
struct speck64_tfm_ctx main_key;
struct speck64_tfm_ctx tweak_key;
};
asmlinkage void speck64_xts_encrypt_neon(const u32 *round_keys, int nrounds,
void *dst, const void *src,
unsigned int nbytes, void *tweak);
asmlinkage void speck64_xts_decrypt_neon(const u32 *round_keys, int nrounds,
void *dst, const void *src,
unsigned int nbytes, void *tweak);
typedef void (*speck64_crypt_one_t)(const struct speck64_tfm_ctx *,
u8 *, const u8 *);
typedef void (*speck64_xts_crypt_many_t)(const u32 *, int, void *,
const void *, unsigned int, void *);
static __always_inline int
__speck64_xts_crypt(struct skcipher_request *req, speck64_crypt_one_t crypt_one,
speck64_xts_crypt_many_t crypt_many)
{
struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
const struct speck64_xts_tfm_ctx *ctx = crypto_skcipher_ctx(tfm);
struct skcipher_walk walk;
__le64 tweak;
int err;
err = skcipher_walk_virt(&walk, req, true);
crypto_speck64_encrypt(&ctx->tweak_key, (u8 *)&tweak, walk.iv);
while (walk.nbytes > 0) {
unsigned int nbytes = walk.nbytes;
u8 *dst = walk.dst.virt.addr;
const u8 *src = walk.src.virt.addr;
if (nbytes >= SPECK_NEON_CHUNK_SIZE && may_use_simd()) {
unsigned int count;
count = round_down(nbytes, SPECK_NEON_CHUNK_SIZE);
kernel_neon_begin();
(*crypt_many)(ctx->main_key.round_keys,
ctx->main_key.nrounds,
dst, src, count, &tweak);
kernel_neon_end();
dst += count;
src += count;
nbytes -= count;
}
/* Handle any remainder with generic code */
while (nbytes >= sizeof(tweak)) {
*(__le64 *)dst = *(__le64 *)src ^ tweak;
(*crypt_one)(&ctx->main_key, dst, dst);
*(__le64 *)dst ^= tweak;
tweak = cpu_to_le64((le64_to_cpu(tweak) << 1) ^
((tweak & cpu_to_le64(1ULL << 63)) ?
0x1B : 0));
dst += sizeof(tweak);
src += sizeof(tweak);
nbytes -= sizeof(tweak);
}
err = skcipher_walk_done(&walk, nbytes);
}
return err;
}
static int speck64_xts_encrypt(struct skcipher_request *req)
{
return __speck64_xts_crypt(req, crypto_speck64_encrypt,
speck64_xts_encrypt_neon);
}
static int speck64_xts_decrypt(struct skcipher_request *req)
{
return __speck64_xts_crypt(req, crypto_speck64_decrypt,
speck64_xts_decrypt_neon);
}
static int speck64_xts_setkey(struct crypto_skcipher *tfm, const u8 *key,
unsigned int keylen)
{
struct speck64_xts_tfm_ctx *ctx = crypto_skcipher_ctx(tfm);
int err;
err = xts_verify_key(tfm, key, keylen);
if (err)
return err;
keylen /= 2;
err = crypto_speck64_setkey(&ctx->main_key, key, keylen);
if (err)
return err;
return crypto_speck64_setkey(&ctx->tweak_key, key + keylen, keylen);
}
static struct skcipher_alg speck_algs[] = {
{
.base.cra_name = "xts(speck128)",
.base.cra_driver_name = "xts-speck128-neon",
.base.cra_priority = 300,
.base.cra_blocksize = SPECK128_BLOCK_SIZE,
.base.cra_ctxsize = sizeof(struct speck128_xts_tfm_ctx),
.base.cra_alignmask = 7,
.base.cra_module = THIS_MODULE,
.min_keysize = 2 * SPECK128_128_KEY_SIZE,
.max_keysize = 2 * SPECK128_256_KEY_SIZE,
.ivsize = SPECK128_BLOCK_SIZE,
.walksize = SPECK_NEON_CHUNK_SIZE,
.setkey = speck128_xts_setkey,
.encrypt = speck128_xts_encrypt,
.decrypt = speck128_xts_decrypt,
}, {
.base.cra_name = "xts(speck64)",
.base.cra_driver_name = "xts-speck64-neon",
.base.cra_priority = 300,
.base.cra_blocksize = SPECK64_BLOCK_SIZE,
.base.cra_ctxsize = sizeof(struct speck64_xts_tfm_ctx),
.base.cra_alignmask = 7,
.base.cra_module = THIS_MODULE,
.min_keysize = 2 * SPECK64_96_KEY_SIZE,
.max_keysize = 2 * SPECK64_128_KEY_SIZE,
.ivsize = SPECK64_BLOCK_SIZE,
.walksize = SPECK_NEON_CHUNK_SIZE,
.setkey = speck64_xts_setkey,
.encrypt = speck64_xts_encrypt,
.decrypt = speck64_xts_decrypt,
}
};
static int __init speck_neon_module_init(void)
{
if (!(elf_hwcap & HWCAP_NEON))
return -ENODEV;
return crypto_register_skciphers(speck_algs, ARRAY_SIZE(speck_algs));
}
static void __exit speck_neon_module_exit(void)
{
crypto_unregister_skciphers(speck_algs, ARRAY_SIZE(speck_algs));
}
module_init(speck_neon_module_init);
module_exit(speck_neon_module_exit);
MODULE_DESCRIPTION("Speck block cipher (NEON-accelerated)");
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Eric Biggers <ebiggers@google.com>");
MODULE_ALIAS_CRYPTO("xts(speck128)");
MODULE_ALIAS_CRYPTO("xts-speck128-neon");
MODULE_ALIAS_CRYPTO("xts(speck64)");
MODULE_ALIAS_CRYPTO("xts-speck64-neon");
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