#include <asm/neon.h>
#include <asm/simd.h>
#include <crypto/aes.h>
#include <crypto/internal/skcipher.h>
#include <crypto/scatterwalk.h>
#include <crypto/xts.h>
#include <linux/module.h>
MODULE_AUTHOR("Ard Biesheuvel <ard.biesheuvel@linaro.org>");
MODULE_DESCRIPTION("Bit sliced AES using NEON instructions");
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[]);
asmlinkage void aesbs_xts_encrypt(u8 out[], u8 const in[], u8 const rk[],
int rounds, int blocks, u8 iv[], int);
asmlinkage void aesbs_xts_decrypt(u8 out[], u8 const in[], u8 const rk[],
int rounds, int blocks, u8 iv[], int);
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 aes_enckey fallback;
};
struct aesbs_xts_ctx {
struct aesbs_ctx key;
struct aes_key fallback;
struct aes_enckey tweak_key;
};
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 = aes_expandkey(&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, false);
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);
kernel_neon_begin();
fn(walk.dst.virt.addr, walk.src.virt.addr, ctx->rk,
ctx->rounds, blocks);
kernel_neon_end();
err = skcipher_walk_done(&walk,
walk.nbytes - blocks * AES_BLOCK_SIZE);
}
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);
int err;
err = aes_prepareenckey(&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.k.rndkeys,
ctx->key.rounds);
kernel_neon_end();
return 0;
}
static int cbc_encrypt(struct skcipher_request *req)
{
struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
const struct aesbs_cbc_ctx *ctx = crypto_skcipher_ctx(tfm);
struct skcipher_walk walk;
unsigned int nbytes;
int err;
err = skcipher_walk_virt(&walk, req, false);
while ((nbytes = walk.nbytes) >= AES_BLOCK_SIZE) {
const u8 *src = walk.src.virt.addr;
u8 *dst = walk.dst.virt.addr;
u8 *prev = walk.iv;
do {
crypto_xor_cpy(dst, src, prev, AES_BLOCK_SIZE);
aes_encrypt(&ctx->fallback, dst, dst);
prev = dst;
src += AES_BLOCK_SIZE;
dst += AES_BLOCK_SIZE;
nbytes -= AES_BLOCK_SIZE;
} while (nbytes >= AES_BLOCK_SIZE);
memcpy(walk.iv, prev, AES_BLOCK_SIZE);
err = skcipher_walk_done(&walk, nbytes);
}
return err;
}
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, false);
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);
kernel_neon_begin();
aesbs_cbc_decrypt(walk.dst.virt.addr, walk.src.virt.addr,
ctx->key.rk, ctx->key.rounds, blocks,
walk.iv);
kernel_neon_end();
err = skcipher_walk_done(&walk,
walk.nbytes - blocks * AES_BLOCK_SIZE);
}
return err;
}
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, false);
while (walk.nbytes > 0) {
const u8 *src = walk.src.virt.addr;
u8 *dst = walk.dst.virt.addr;
unsigned int bytes = walk.nbytes;
if (unlikely(bytes < AES_BLOCK_SIZE))
src = dst = memcpy(buf + sizeof(buf) - bytes,
src, bytes);
else if (walk.nbytes < walk.total)
bytes &= ~(8 * AES_BLOCK_SIZE - 1);
kernel_neon_begin();
aesbs_ctr_encrypt(dst, src, ctx->rk, ctx->rounds, bytes, walk.iv);
kernel_neon_end();
if (unlikely(bytes < AES_BLOCK_SIZE))
memcpy(walk.dst.virt.addr,
buf + sizeof(buf) - bytes, bytes);
err = skcipher_walk_done(&walk, walk.nbytes - bytes);
}
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 = aes_preparekey(&ctx->fallback, in_key, key_len);
if (err)
return err;
err = aes_prepareenckey(&ctx->tweak_key, in_key + key_len, key_len);
if (err)
return err;
return aesbs_setkey(tfm, in_key, key_len);
}
static int __xts_crypt(struct skcipher_request *req, bool encrypt,
void (*fn)(u8 out[], u8 const in[], u8 const rk[],
int rounds, int blocks, u8 iv[], int))
{
struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
struct aesbs_xts_ctx *ctx = crypto_skcipher_ctx(tfm);
const int rounds = ctx->key.rounds;
int tail = req->cryptlen % AES_BLOCK_SIZE;
struct skcipher_request subreq;
u8 buf[2 * AES_BLOCK_SIZE];
struct skcipher_walk walk;
int err;
if (req->cryptlen < AES_BLOCK_SIZE)
return -EINVAL;
if (unlikely(tail)) {
skcipher_request_set_tfm(&subreq, tfm);
skcipher_request_set_callback(&subreq,
skcipher_request_flags(req),
NULL, NULL);
skcipher_request_set_crypt(&subreq, req->src, req->dst,
req->cryptlen - tail, req->iv);
req = &subreq;
}
err = skcipher_walk_virt(&walk, req, true);
if (err)
return err;
aes_encrypt(&ctx->tweak_key, walk.iv, walk.iv);
while (walk.nbytes >= AES_BLOCK_SIZE) {
unsigned int blocks = walk.nbytes / AES_BLOCK_SIZE;
int reorder_last_tweak = !encrypt && tail > 0;
if (walk.nbytes < walk.total) {
blocks = round_down(blocks,
walk.stride / AES_BLOCK_SIZE);
reorder_last_tweak = 0;
}
kernel_neon_begin();
fn(walk.dst.virt.addr, walk.src.virt.addr, ctx->key.rk,
rounds, blocks, walk.iv, reorder_last_tweak);
kernel_neon_end();
err = skcipher_walk_done(&walk,
walk.nbytes - blocks * AES_BLOCK_SIZE);
}
if (err || likely(!tail))
return err;
scatterwalk_map_and_copy(buf, req->dst, req->cryptlen - AES_BLOCK_SIZE,
AES_BLOCK_SIZE, 0);
memcpy(buf + AES_BLOCK_SIZE, buf, tail);
scatterwalk_map_and_copy(buf, req->src, req->cryptlen, tail, 0);
crypto_xor(buf, req->iv, AES_BLOCK_SIZE);
if (encrypt)
aes_encrypt(&ctx->fallback, buf, buf);
else
aes_decrypt(&ctx->fallback, buf, buf);
crypto_xor(buf, req->iv, AES_BLOCK_SIZE);
scatterwalk_map_and_copy(buf, req->dst, req->cryptlen - AES_BLOCK_SIZE,
AES_BLOCK_SIZE + tail, 1);
return 0;
}
static int xts_encrypt(struct skcipher_request *req)
{
return __xts_crypt(req, true, aesbs_xts_encrypt);
}
static int xts_decrypt(struct skcipher_request *req)
{
return __xts_crypt(req, false, 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,
.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,
.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,
.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,
.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 void aes_exit(void)
{
crypto_unregister_skciphers(aes_algs, ARRAY_SIZE(aes_algs));
}
static int __init aes_init(void)
{
if (!(elf_hwcap & HWCAP_NEON))
return -ENODEV;
return crypto_register_skciphers(aes_algs, ARRAY_SIZE(aes_algs));
}
module_init(aes_init);
module_exit(aes_exit);
