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remarkable-linux/arch/arm/crypto/aes-neonbs-glue.c
Ard Biesheuvel b56f5cbc7e crypto: arm/aes-neonbs - resolve fallback cipher at runtime 
Currently, the bit sliced NEON AES code for ARM has a link time
dependency on the scalar ARM asm implementation, which it uses as a
fallback to perform CBC encryption and the encryption of the initial
XTS tweak.

The bit sliced NEON code is both fast and time invariant, which makes
it a reasonable default on hardware that supports it. However, the
ARM asm code it pulls in is not time invariant, and due to the way it
is linked in, cannot be overridden by the new generic time invariant
driver. In fact, it will not be used at all, given that the ARM asm
code registers itself as a cipher with a priority that exceeds the
priority of the fixed time cipher.

So remove the link time dependency, and allocate the fallback cipher
via the crypto API. Note that this requires this driver's module_init
call to be replaced with late_initcall, so that the (possibly generic)
fallback cipher is guaranteed to be available when the builtin test
is performed at registration time.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2017-03-09 18:34:16 +08:00

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/*
* Bit sliced AES using NEON instructions
*
* Copyright (C) 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
* published by the Free Software Foundation.
*/
#include <asm/neon.h>
#include <crypto/aes.h>
#include <crypto/cbc.h>
#include <crypto/internal/simd.h>
#include <crypto/internal/skcipher.h>
#include <crypto/xts.h>
#include <linux/module.h>
MODULE_AUTHOR("Ard Biesheuvel <ard.biesheuvel@linaro.org>");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS_CRYPTO("ecb(aes)");
MODULE_ALIAS_CRYPTO("cbc(aes)");
MODULE_ALIAS_CRYPTO("ctr(aes)");
MODULE_ALIAS_CRYPTO("xts(aes)");
asmlinkage void aesbs_convert_key(u8 out[], u32 const rk[], int rounds);
asmlinkage void aesbs_ecb_encrypt(u8 out[], u8 const in[], u8 const rk[],
int rounds, int blocks);
asmlinkage void aesbs_ecb_decrypt(u8 out[], u8 const in[], u8 const rk[],
int rounds, int blocks);
asmlinkage void aesbs_cbc_decrypt(u8 out[], u8 const in[], u8 const rk[],
int rounds, int blocks, u8 iv[]);
asmlinkage void aesbs_ctr_encrypt(u8 out[], u8 const in[], u8 const rk[],
int rounds, int blocks, u8 ctr[], u8 final[]);
asmlinkage void aesbs_xts_encrypt(u8 out[], u8 const in[], u8 const rk[],
int rounds, int blocks, u8 iv[]);
asmlinkage void aesbs_xts_decrypt(u8 out[], u8 const in[], u8 const rk[],
int rounds, int blocks, u8 iv[]);
struct aesbs_ctx {
int rounds;
u8 rk[13 * (8 * AES_BLOCK_SIZE) + 32] __aligned(AES_BLOCK_SIZE);
};
struct aesbs_cbc_ctx {
struct aesbs_ctx key;
struct crypto_cipher *enc_tfm;
};
struct aesbs_xts_ctx {
struct aesbs_ctx key;
struct crypto_cipher *tweak_tfm;
};
static int aesbs_setkey(struct crypto_skcipher *tfm, const u8 *in_key,
unsigned int key_len)
{
struct aesbs_ctx *ctx = crypto_skcipher_ctx(tfm);
struct crypto_aes_ctx rk;
int err;
err = crypto_aes_expand_key(&rk, in_key, key_len);
if (err)
return err;
ctx->rounds = 6 + key_len / 4;
kernel_neon_begin();
aesbs_convert_key(ctx->rk, rk.key_enc, ctx->rounds);
kernel_neon_end();
return 0;
}
static int __ecb_crypt(struct skcipher_request *req,
void (*fn)(u8 out[], u8 const in[], u8 const rk[],
int rounds, int blocks))
{
struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
struct aesbs_ctx *ctx = crypto_skcipher_ctx(tfm);
struct skcipher_walk walk;
int err;
err = skcipher_walk_virt(&walk, req, true);
kernel_neon_begin();
while (walk.nbytes >= AES_BLOCK_SIZE) {
unsigned int blocks = walk.nbytes / AES_BLOCK_SIZE;
if (walk.nbytes < walk.total)
blocks = round_down(blocks,
walk.stride / AES_BLOCK_SIZE);
fn(walk.dst.virt.addr, walk.src.virt.addr, ctx->rk,
ctx->rounds, blocks);
err = skcipher_walk_done(&walk,
walk.nbytes - blocks * AES_BLOCK_SIZE);
}
kernel_neon_end();
return err;
}
static int ecb_encrypt(struct skcipher_request *req)
{
return __ecb_crypt(req, aesbs_ecb_encrypt);
}
static int ecb_decrypt(struct skcipher_request *req)
{
return __ecb_crypt(req, aesbs_ecb_decrypt);
}
static int aesbs_cbc_setkey(struct crypto_skcipher *tfm, const u8 *in_key,
unsigned int key_len)
{
struct aesbs_cbc_ctx *ctx = crypto_skcipher_ctx(tfm);
struct crypto_aes_ctx rk;
int err;
err = crypto_aes_expand_key(&rk, in_key, key_len);
if (err)
return err;
ctx->key.rounds = 6 + key_len / 4;
kernel_neon_begin();
aesbs_convert_key(ctx->key.rk, rk.key_enc, ctx->key.rounds);
kernel_neon_end();
return crypto_cipher_setkey(ctx->enc_tfm, in_key, key_len);
}
static void cbc_encrypt_one(struct crypto_skcipher *tfm, const u8 *src, u8 *dst)
{
struct aesbs_cbc_ctx *ctx = crypto_skcipher_ctx(tfm);
crypto_cipher_encrypt_one(ctx->enc_tfm, dst, src);
}
static int cbc_encrypt(struct skcipher_request *req)
{
return crypto_cbc_encrypt_walk(req, cbc_encrypt_one);
}
static int cbc_decrypt(struct skcipher_request *req)
{
struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
struct aesbs_cbc_ctx *ctx = crypto_skcipher_ctx(tfm);
struct skcipher_walk walk;
int err;
err = skcipher_walk_virt(&walk, req, true);
kernel_neon_begin();
while (walk.nbytes >= AES_BLOCK_SIZE) {
unsigned int blocks = walk.nbytes / AES_BLOCK_SIZE;
if (walk.nbytes < walk.total)
blocks = round_down(blocks,
walk.stride / AES_BLOCK_SIZE);
aesbs_cbc_decrypt(walk.dst.virt.addr, walk.src.virt.addr,
ctx->key.rk, ctx->key.rounds, blocks,
walk.iv);
err = skcipher_walk_done(&walk,
walk.nbytes - blocks * AES_BLOCK_SIZE);
}
kernel_neon_end();
return err;
}
static int cbc_init(struct crypto_tfm *tfm)
{
struct aesbs_cbc_ctx *ctx = crypto_tfm_ctx(tfm);
ctx->enc_tfm = crypto_alloc_cipher("aes", 0, 0);
if (IS_ERR(ctx->enc_tfm))
return PTR_ERR(ctx->enc_tfm);
return 0;
}
static void cbc_exit(struct crypto_tfm *tfm)
{
struct aesbs_cbc_ctx *ctx = crypto_tfm_ctx(tfm);
crypto_free_cipher(ctx->enc_tfm);
}
static int ctr_encrypt(struct skcipher_request *req)
{
struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
struct aesbs_ctx *ctx = crypto_skcipher_ctx(tfm);
struct skcipher_walk walk;
u8 buf[AES_BLOCK_SIZE];
int err;
err = skcipher_walk_virt(&walk, req, true);
kernel_neon_begin();
while (walk.nbytes > 0) {
unsigned int blocks = walk.nbytes / AES_BLOCK_SIZE;
u8 *final = (walk.total % AES_BLOCK_SIZE) ? buf : NULL;
if (walk.nbytes < walk.total) {
blocks = round_down(blocks,
walk.stride / AES_BLOCK_SIZE);
final = NULL;
}
aesbs_ctr_encrypt(walk.dst.virt.addr, walk.src.virt.addr,
ctx->rk, ctx->rounds, blocks, walk.iv, final);
if (final) {
u8 *dst = walk.dst.virt.addr + blocks * AES_BLOCK_SIZE;
u8 *src = walk.src.virt.addr + blocks * AES_BLOCK_SIZE;
if (dst != src)
memcpy(dst, src, walk.total % AES_BLOCK_SIZE);
crypto_xor(dst, final, walk.total % AES_BLOCK_SIZE);
err = skcipher_walk_done(&walk, 0);
break;
}
err = skcipher_walk_done(&walk,
walk.nbytes - blocks * AES_BLOCK_SIZE);
}
kernel_neon_end();
return err;
}
static int aesbs_xts_setkey(struct crypto_skcipher *tfm, const u8 *in_key,
unsigned int key_len)
{
struct aesbs_xts_ctx *ctx = crypto_skcipher_ctx(tfm);
int err;
err = xts_verify_key(tfm, in_key, key_len);
if (err)
return err;
key_len /= 2;
err = crypto_cipher_setkey(ctx->tweak_tfm, in_key + key_len, key_len);
if (err)
return err;
return aesbs_setkey(tfm, in_key, key_len);
}
static int xts_init(struct crypto_tfm *tfm)
{
struct aesbs_xts_ctx *ctx = crypto_tfm_ctx(tfm);
ctx->tweak_tfm = crypto_alloc_cipher("aes", 0, 0);
if (IS_ERR(ctx->tweak_tfm))
return PTR_ERR(ctx->tweak_tfm);
return 0;
}
static void xts_exit(struct crypto_tfm *tfm)
{
struct aesbs_xts_ctx *ctx = crypto_tfm_ctx(tfm);
crypto_free_cipher(ctx->tweak_tfm);
}
static int __xts_crypt(struct skcipher_request *req,
void (*fn)(u8 out[], u8 const in[], u8 const rk[],
int rounds, int blocks, u8 iv[]))
{
struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
struct aesbs_xts_ctx *ctx = crypto_skcipher_ctx(tfm);
struct skcipher_walk walk;
int err;
err = skcipher_walk_virt(&walk, req, true);
crypto_cipher_encrypt_one(ctx->tweak_tfm, walk.iv, walk.iv);
kernel_neon_begin();
while (walk.nbytes >= AES_BLOCK_SIZE) {
unsigned int blocks = walk.nbytes / AES_BLOCK_SIZE;
if (walk.nbytes < walk.total)
blocks = round_down(blocks,
walk.stride / AES_BLOCK_SIZE);
fn(walk.dst.virt.addr, walk.src.virt.addr, ctx->key.rk,
ctx->key.rounds, blocks, walk.iv);
err = skcipher_walk_done(&walk,
walk.nbytes - blocks * AES_BLOCK_SIZE);
}
kernel_neon_end();
return err;
}
static int xts_encrypt(struct skcipher_request *req)
{
return __xts_crypt(req, aesbs_xts_encrypt);
}
static int xts_decrypt(struct skcipher_request *req)
{
return __xts_crypt(req, aesbs_xts_decrypt);
}
static struct skcipher_alg aes_algs[] = { {
.base.cra_name = "__ecb(aes)",
.base.cra_driver_name = "__ecb-aes-neonbs",
.base.cra_priority = 250,
.base.cra_blocksize = AES_BLOCK_SIZE,
.base.cra_ctxsize = sizeof(struct aesbs_ctx),
.base.cra_module = THIS_MODULE,
.base.cra_flags = CRYPTO_ALG_INTERNAL,
.min_keysize = AES_MIN_KEY_SIZE,
.max_keysize = AES_MAX_KEY_SIZE,
.walksize = 8 * AES_BLOCK_SIZE,
.setkey = aesbs_setkey,
.encrypt = ecb_encrypt,
.decrypt = ecb_decrypt,
}, {
.base.cra_name = "__cbc(aes)",
.base.cra_driver_name = "__cbc-aes-neonbs",
.base.cra_priority = 250,
.base.cra_blocksize = AES_BLOCK_SIZE,
.base.cra_ctxsize = sizeof(struct aesbs_cbc_ctx),
.base.cra_module = THIS_MODULE,
.base.cra_flags = CRYPTO_ALG_INTERNAL,
.base.cra_init = cbc_init,
.base.cra_exit = cbc_exit,
.min_keysize = AES_MIN_KEY_SIZE,
.max_keysize = AES_MAX_KEY_SIZE,
.walksize = 8 * AES_BLOCK_SIZE,
.ivsize = AES_BLOCK_SIZE,
.setkey = aesbs_cbc_setkey,
.encrypt = cbc_encrypt,
.decrypt = cbc_decrypt,
}, {
.base.cra_name = "__ctr(aes)",
.base.cra_driver_name = "__ctr-aes-neonbs",
.base.cra_priority = 250,
.base.cra_blocksize = 1,
.base.cra_ctxsize = sizeof(struct aesbs_ctx),
.base.cra_module = THIS_MODULE,
.base.cra_flags = CRYPTO_ALG_INTERNAL,
.min_keysize = AES_MIN_KEY_SIZE,
.max_keysize = AES_MAX_KEY_SIZE,
.chunksize = AES_BLOCK_SIZE,
.walksize = 8 * AES_BLOCK_SIZE,
.ivsize = AES_BLOCK_SIZE,
.setkey = aesbs_setkey,
.encrypt = ctr_encrypt,
.decrypt = ctr_encrypt,
}, {
.base.cra_name = "__xts(aes)",
.base.cra_driver_name = "__xts-aes-neonbs",
.base.cra_priority = 250,
.base.cra_blocksize = AES_BLOCK_SIZE,
.base.cra_ctxsize = sizeof(struct aesbs_xts_ctx),
.base.cra_module = THIS_MODULE,
.base.cra_flags = CRYPTO_ALG_INTERNAL,
.base.cra_init = xts_init,
.base.cra_exit = xts_exit,
.min_keysize = 2 * AES_MIN_KEY_SIZE,
.max_keysize = 2 * AES_MAX_KEY_SIZE,
.walksize = 8 * AES_BLOCK_SIZE,
.ivsize = AES_BLOCK_SIZE,
.setkey = aesbs_xts_setkey,
.encrypt = xts_encrypt,
.decrypt = xts_decrypt,
} };
static struct simd_skcipher_alg *aes_simd_algs[ARRAY_SIZE(aes_algs)];
static void aes_exit(void)
{
int i;
for (i = 0; i < ARRAY_SIZE(aes_simd_algs); i++)
if (aes_simd_algs[i])
simd_skcipher_free(aes_simd_algs[i]);
crypto_unregister_skciphers(aes_algs, ARRAY_SIZE(aes_algs));
}
static int __init aes_init(void)
{
struct simd_skcipher_alg *simd;
const char *basename;
const char *algname;
const char *drvname;
int err;
int i;
if (!(elf_hwcap & HWCAP_NEON))
return -ENODEV;
err = crypto_register_skciphers(aes_algs, ARRAY_SIZE(aes_algs));
if (err)
return err;
for (i = 0; i < ARRAY_SIZE(aes_algs); i++) {
if (!(aes_algs[i].base.cra_flags & CRYPTO_ALG_INTERNAL))
continue;
algname = aes_algs[i].base.cra_name + 2;
drvname = aes_algs[i].base.cra_driver_name + 2;
basename = aes_algs[i].base.cra_driver_name;
simd = simd_skcipher_create_compat(algname, drvname, basename);
err = PTR_ERR(simd);
if (IS_ERR(simd))
goto unregister_simds;
aes_simd_algs[i] = simd;
}
return 0;
unregister_simds:
aes_exit();
return err;
}
late_initcall(aes_init);
module_exit(aes_exit);
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