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/*
* aes-ccm-glue.c - AES-CCM transform for ARMv8 with Crypto Extensions
*
* Copyright (C) 2013 - 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 <asm/simd.h>
#include <asm/unaligned.h>
#include <crypto/aes.h>
#include <crypto/scatterwalk.h>
#include <crypto/internal/aead.h>
#include <crypto/internal/skcipher.h>
#include <linux/module.h>
#include "aes-ce-setkey.h"
static int num_rounds(struct crypto_aes_ctx *ctx)
{
/*
* # of rounds specified by AES:
* 128 bit key 10 rounds
* 192 bit key 12 rounds
* 256 bit key 14 rounds
* => n byte key => 6 + (n/4) rounds
*/
return 6 + ctx->key_length / 4;
}
asmlinkage void ce_aes_ccm_auth_data(u8 mac[], u8 const in[], u32 abytes,
u32 *macp, u32 const rk[], u32 rounds);
asmlinkage void ce_aes_ccm_encrypt(u8 out[], u8 const in[], u32 cbytes,
u32 const rk[], u32 rounds, u8 mac[],
u8 ctr[]);
asmlinkage void ce_aes_ccm_decrypt(u8 out[], u8 const in[], u32 cbytes,
u32 const rk[], u32 rounds, u8 mac[],
u8 ctr[]);
asmlinkage void ce_aes_ccm_final(u8 mac[], u8 const ctr[], u32 const rk[],
u32 rounds);
asmlinkage void __aes_arm64_encrypt(u32 *rk, u8 *out, const u8 *in, int rounds);
static int ccm_setkey(struct crypto_aead *tfm, const u8 *in_key,
unsigned int key_len)
{
struct crypto_aes_ctx *ctx = crypto_aead_ctx(tfm);
int ret;
ret = ce_aes_expandkey(ctx, in_key, key_len);
if (!ret)
return 0;
tfm->base.crt_flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
return -EINVAL;
}
static int ccm_setauthsize(struct crypto_aead *tfm, unsigned int authsize)
{
if ((authsize & 1) || authsize < 4)
return -EINVAL;
return 0;
}
static int ccm_init_mac(struct aead_request *req, u8 maciv[], u32 msglen)
{
struct crypto_aead *aead = crypto_aead_reqtfm(req);
__be32 *n = (__be32 *)&maciv[AES_BLOCK_SIZE - 8];
u32 l = req->iv[0] + 1;
/* verify that CCM dimension 'L' is set correctly in the IV */
if (l < 2 || l > 8)
return -EINVAL;
/* verify that msglen can in fact be represented in L bytes */
if (l < 4 && msglen >> (8 * l))
return -EOVERFLOW;
/*
* Even if the CCM spec allows L values of up to 8, the Linux cryptoapi
* uses a u32 type to represent msglen so the top 4 bytes are always 0.
*/
n[0] = 0;
n[1] = cpu_to_be32(msglen);
memcpy(maciv, req->iv, AES_BLOCK_SIZE - l);
/*
* Meaning of byte 0 according to CCM spec (RFC 3610/NIST 800-38C)
* - bits 0..2 : max # of bytes required to represent msglen, minus 1
* (already set by caller)
* - bits 3..5 : size of auth tag (1 => 4 bytes, 2 => 6 bytes, etc)
* - bit 6 : indicates presence of authenticate-only data
*/
maciv[0] |= (crypto_aead_authsize(aead) - 2) << 2;
if (req->assoclen)
maciv[0] |= 0x40;
memset(&req->iv[AES_BLOCK_SIZE - l], 0, l);
return 0;
}
static void ccm_update_mac(struct crypto_aes_ctx *key, u8 mac[], u8 const in[],
u32 abytes, u32 *macp)
{
if (may_use_simd()) {
kernel_neon_begin();
ce_aes_ccm_auth_data(mac, in, abytes, macp, key->key_enc,
num_rounds(key));
kernel_neon_end();
} else {
if (*macp > 0 && *macp < AES_BLOCK_SIZE) {
int added = min(abytes, AES_BLOCK_SIZE - *macp);
crypto_xor(&mac[*macp], in, added);
*macp += added;
in += added;
abytes -= added;
}
while (abytes > AES_BLOCK_SIZE) {
__aes_arm64_encrypt(key->key_enc, mac, mac,
num_rounds(key));
crypto_xor(mac, in, AES_BLOCK_SIZE);
in += AES_BLOCK_SIZE;
abytes -= AES_BLOCK_SIZE;
}
if (abytes > 0) {
__aes_arm64_encrypt(key->key_enc, mac, mac,
num_rounds(key));
crypto_xor(mac, in, abytes);
*macp = abytes;
} else {
*macp = 0;
}
}
}
static void ccm_calculate_auth_mac(struct aead_request *req, u8 mac[])
{
struct crypto_aead *aead = crypto_aead_reqtfm(req);
struct crypto_aes_ctx *ctx = crypto_aead_ctx(aead);
struct __packed { __be16 l; __be32 h; u16 len; } ltag;
struct scatter_walk walk;
u32 len = req->assoclen;
u32 macp = 0;
/* prepend the AAD with a length tag */
if (len < 0xff00) {
ltag.l = cpu_to_be16(len);
ltag.len = 2;
} else {
ltag.l = cpu_to_be16(0xfffe);
put_unaligned_be32(len, <ag.h);
ltag.len = 6;
}
ccm_update_mac(ctx, mac, (u8 *)<ag, ltag.len, &macp);
scatterwalk_start(&walk, req->src);
do {
u32 n = scatterwalk_clamp(&walk, len);
u8 *p;
if (!n) {
scatterwalk_start(&walk, sg_next(walk.sg));
n = scatterwalk_clamp(&walk, len);
}
p = scatterwalk_map(&walk);
ccm_update_mac(ctx, mac, p, n, &macp);
len -= n;
scatterwalk_unmap(p);
scatterwalk_advance(&walk, n);
scatterwalk_done(&walk, 0, len);
} while (len);
}
static int ccm_crypt_fallback(struct skcipher_walk *walk, u8 mac[], u8 iv0[],
struct crypto_aes_ctx *ctx, bool enc)
{
u8 buf[AES_BLOCK_SIZE];
int err = 0;
while (walk->nbytes) {
int blocks = walk->nbytes / AES_BLOCK_SIZE;
u32 tail = walk->nbytes % AES_BLOCK_SIZE;
u8 *dst = walk->dst.virt.addr;
u8 *src = walk->src.virt.addr;
u32 nbytes = walk->nbytes;
if (nbytes == walk->total && tail > 0) {
blocks++;
tail = 0;
}
do {
u32 bsize = AES_BLOCK_SIZE;
if (nbytes < AES_BLOCK_SIZE)
bsize = nbytes;
crypto_inc(walk->iv, AES_BLOCK_SIZE);
__aes_arm64_encrypt(ctx->key_enc, buf, walk->iv,
num_rounds(ctx));
__aes_arm64_encrypt(ctx->key_enc, mac, mac,
num_rounds(ctx));
if (enc)
crypto_xor(mac, src, bsize);
crypto_xor_cpy(dst, src, buf, bsize);
if (!enc)
crypto_xor(mac, dst, bsize);
dst += bsize;
src += bsize;
nbytes -= bsize;
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