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crypto: arm64/aes-bs - implement non-SIMD fallback for AES-CTR

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Of the various chaining modes implemented by the bit sliced AES driver,
only CTR is exposed as a synchronous cipher, and requires a fallback in
order to remain usable once we update the kernel mode NEON handling logic
to disallow nested use. So wire up the existing CTR fallback C code.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This commit is contained in:
Ard Biesheuvel 2017-07-24 11:28:15 +01:00 committed by Herbert Xu
parent 611d5324f4
commit ec808bbef0
2 changed files with 44 additions and 5 deletions
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1
arch/arm64/crypto/Kconfig
View File

@ -89,6 +89,7 @@ config CRYPTO_AES_ARM64_BS
depends on KERNEL_MODE_NEON
select CRYPTO_BLKCIPHER
select CRYPTO_AES_ARM64_NEON_BLK
select CRYPTO_AES_ARM64
select CRYPTO_SIMD
endif

48
arch/arm64/crypto/aes-neonbs-glue.c
View File

@ -1,7 +1,7 @@
/*
* Bit sliced AES using NEON instructions
*
* Copyright (C) 2016 Linaro Ltd <ard.biesheuvel@linaro.org>
* Copyright (C) 2016 - 2017 Linaro Ltd <ard.biesheuvel@linaro.org>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
@ -9,12 +9,15 @@
*/
#include <asm/neon.h>
#include <asm/simd.h>
#include <crypto/aes.h>
#include <crypto/internal/simd.h>
#include <crypto/internal/skcipher.h>
#include <crypto/xts.h>
#include <linux/module.h>
#include "aes-ctr-fallback.h"
MODULE_AUTHOR("Ard Biesheuvel <ard.biesheuvel@linaro.org>");
MODULE_LICENSE("GPL v2");
@ -58,6 +61,11 @@ struct aesbs_cbc_ctx {
u32 enc[AES_MAX_KEYLENGTH_U32];
};
struct aesbs_ctr_ctx {
struct aesbs_ctx key; /* must be first member */
struct crypto_aes_ctx fallback;
};
struct aesbs_xts_ctx {
struct aesbs_ctx key;
u32 twkey[AES_MAX_KEYLENGTH_U32];
@ -196,6 +204,25 @@ static int cbc_decrypt(struct skcipher_request *req)
return err;
}
static int aesbs_ctr_setkey_sync(struct crypto_skcipher *tfm, const u8 *in_key,
unsigned int key_len)
{
struct aesbs_ctr_ctx *ctx = crypto_skcipher_ctx(tfm);
int err;
err = crypto_aes_expand_key(&ctx->fallback, in_key, key_len);
if (err)
return err;
ctx->key.rounds = 6 + key_len / 4;
kernel_neon_begin();
aesbs_convert_key(ctx->key.rk, ctx->fallback.key_enc, ctx->key.rounds);
kernel_neon_end();
return 0;
}
static int ctr_encrypt(struct skcipher_request *req)
{
struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
@ -259,6 +286,17 @@ static int aesbs_xts_setkey(struct crypto_skcipher *tfm, const u8 *in_key,
return aesbs_setkey(tfm, in_key, key_len);
}
static int ctr_encrypt_sync(struct skcipher_request *req)
{
struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
struct aesbs_ctr_ctx *ctx = crypto_skcipher_ctx(tfm);
if (!may_use_simd())
return aes_ctr_encrypt_fallback(&ctx->fallback, req);
return ctr_encrypt(req);
}
static int __xts_crypt(struct skcipher_request *req,
void (*fn)(u8 out[], u8 const in[], u8 const rk[],
int rounds, int blocks, u8 iv[]))
@ -355,7 +393,7 @@ static struct skcipher_alg aes_algs[] = { {
.base.cra_driver_name = "ctr-aes-neonbs",
.base.cra_priority = 250 - 1,
.base.cra_blocksize = 1,
.base.cra_ctxsize = sizeof(struct aesbs_ctx),
.base.cra_ctxsize = sizeof(struct aesbs_ctr_ctx),
.base.cra_module = THIS_MODULE,
.min_keysize = AES_MIN_KEY_SIZE,
@ -363,9 +401,9 @@ static struct skcipher_alg aes_algs[] = { {
.chunksize = AES_BLOCK_SIZE,
.walksize = 8 * AES_BLOCK_SIZE,
.ivsize = AES_BLOCK_SIZE,
.setkey = aesbs_setkey,
.encrypt = ctr_encrypt,
.decrypt = ctr_encrypt,
.setkey = aesbs_ctr_setkey_sync,
.encrypt = ctr_encrypt_sync,
.decrypt = ctr_encrypt_sync,
}, {
.base.cra_name = "__xts(aes)",
.base.cra_driver_name = "__xts-aes-neonbs",