glue_helper.c
// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Shared glue code for 128bit block ciphers
*
* Copyright © 2012-2013 Jussi Kivilinna <jussi.kivilinna@iki.fi>
*
* CBC & ECB parts based on code (crypto/cbc.c,ecb.c) by:
* Copyright (c) 2006 Herbert Xu <herbert@gondor.apana.org.au>
* CTR part based on code (crypto/ctr.c) by:
* (C) Copyright IBM Corp. 2007 - Joy Latten <latten@us.ibm.com>
*/
#include <linux/module.h>
#include <crypto/b128ops.h>
#include <crypto/gf128mul.h>
#include <crypto/internal/skcipher.h>
#include <crypto/scatterwalk.h>
#include <crypto/xts.h>
#include <asm/crypto/glue_helper.h>
int glue_ecb_req_128bit(const struct common_glue_ctx *gctx,
struct skcipher_request *req)
{
void *ctx = crypto_skcipher_ctx(crypto_skcipher_reqtfm(req));
const unsigned int bsize = 128 / 8;
struct skcipher_walk walk;
bool fpu_enabled = false;
unsigned int nbytes;
int err;
err = skcipher_walk_virt(&walk, req, false);
while ((nbytes = walk.nbytes)) {
const u8 *src = walk.src.virt.addr;
u8 *dst = walk.dst.virt.addr;
unsigned int func_bytes;
unsigned int i;
fpu_enabled = glue_fpu_begin(bsize, gctx->fpu_blocks_limit,
&walk, fpu_enabled, nbytes);
for (i = 0; i < gctx->num_funcs; i++) {
func_bytes = bsize * gctx->funcs[i].num_blocks;
if (nbytes < func_bytes)
continue;
/* Process multi-block batch */
do {
gctx->funcs[i].fn_u.ecb(ctx, dst, src);
src += func_bytes;
dst += func_bytes;
nbytes -= func_bytes;
} while (nbytes >= func_bytes);
if (nbytes < bsize)
break;
}
err = skcipher_walk_done(&walk, nbytes);
}
glue_fpu_end(fpu_enabled);
return err;
}
EXPORT_SYMBOL_GPL(glue_ecb_req_128bit);
int glue_cbc_encrypt_req_128bit(const common_glue_func_t fn,
struct skcipher_request *req)
{
void *ctx = crypto_skcipher_ctx(crypto_skcipher_reqtfm(req));
const unsigned int bsize = 128 / 8;
struct skcipher_walk walk;
unsigned int nbytes;
int err;
err = skcipher_walk_virt(&walk, req, false);
while ((nbytes = walk.nbytes)) {
const u128 *src = (u128 *)walk.src.virt.addr;
u128 *dst = (u128 *)walk.dst.virt.addr;
u128 *iv = (u128 *)walk.iv;
do {
u128_xor(dst, src, iv);
fn(ctx, (u8 *)dst, (u8 *)dst);
iv = dst;
src++;
dst++;
nbytes -= bsize;
} while (nbytes >= bsize);
*(u128 *)walk.iv = *iv;
err = skcipher_walk_done(&walk, nbytes);
}
return err;
}
EXPORT_SYMBOL_GPL(glue_cbc_encrypt_req_128bit);
int glue_cbc_decrypt_req_128bit(const struct common_glue_ctx *gctx,
struct skcipher_request *req)
{
void *ctx = crypto_skcipher_ctx(crypto_skcipher_reqtfm(req));
const unsigned int bsize = 128 / 8;
struct skcipher_walk walk;
bool fpu_enabled = false;
unsigned int nbytes;
int err;
err = skcipher_walk_virt(&walk, req, false);
while ((nbytes = walk.nbytes)) {
const u128 *src = walk.src.virt.addr;
u128 *dst = walk.dst.virt.addr;
unsigned int func_bytes, num_blocks;
unsigned int i;
u128 last_iv;
fpu_enabled = glue_fpu_begin(bsize, gctx->fpu_blocks_limit,
&walk, fpu_enabled, nbytes);
/* Start of the last block. */
src += nbytes / bsize - 1;
dst += nbytes / bsize - 1;
last_iv = *src;
for (i = 0; i < gctx->num_funcs; i++) {
num_blocks = gctx->funcs[i].num_blocks;
func_bytes = bsize * num_blocks;
if (nbytes < func_bytes)
continue;
/* Process multi-block batch */
do {
src -= num_blocks - 1;
dst -= num_blocks - 1;
gctx->funcs[i].fn_u.cbc(ctx, (u8 *)dst,
(const u8 *)src);
nbytes -= func_bytes;
if (nbytes < bsize)
goto done;
u128_xor(dst, dst, --src);
dst--;
} while (nbytes >= func_bytes);
}
done:
u128_xor(dst, dst, (u128 *)walk.iv);
*(u128 *)walk.iv = last_iv;
err = skcipher_walk_done(&walk, nbytes);
}
glue_fpu_end(fpu_enabled);
return err;
}
EXPORT_SYMBOL_GPL(glue_cbc_decrypt_req_128bit);
int glue_ctr_req_128bit(const struct common_glue_ctx *gctx,
struct skcipher_request *req)
{
void *ctx = crypto_skcipher_ctx(crypto_skcipher_reqtfm(req));
const unsigned int bsize = 128 / 8;
struct skcipher_walk walk;
bool fpu_enabled = false;
unsigned int nbytes;
int err;
err = skcipher_walk_virt(&walk, req, false);
while ((nbytes = walk.nbytes) >= bsize) {
const u128 *src = walk.src.virt.addr;
u128 *dst = walk.dst.virt.addr;
unsigned int func_bytes, num_blocks;
unsigned int i;
le128 ctrblk;
fpu_enabled = glue_fpu_begin(bsize, gctx->fpu_blocks_limit,
&walk, fpu_enabled, nbytes);
be128_to_le128(&ctrblk, (be128 *)walk.iv);
for (i = 0; i < gctx->num_funcs; i++) {
num_blocks = gctx->funcs[i].num_blocks;
func_bytes = bsize * num_blocks;
if (nbytes < func_bytes)
continue;
/* Process multi-block batch */
do {
gctx->funcs[i].fn_u.ctr(ctx, (u8 *)dst,
(const u8 *)src,
&ctrblk);
src += num_blocks;
dst += num_blocks;
nbytes -= func_bytes;
} while (nbytes >= func_bytes);
if (nbytes < bsize)
break;
}
le128_to_be128((be128 *)walk.iv, &ctrblk);
err = skcipher_walk_done(&walk, nbytes);
}
glue_fpu_end(fpu_enabled);
if (nbytes) {
le128 ctrblk;
u128 tmp;
be128_to_le128(&ctrblk, (be128 *)walk.iv);
memcpy(&tmp, walk.src.virt.addr, nbytes);
gctx->funcs[gctx->num_funcs - 1].fn_u.ctr(ctx, (u8 *)&tmp,
(const u8 *)&tmp,
&ctrblk);
memcpy(walk.dst.virt.addr, &tmp, nbytes);
le128_to_be128((be128 *)walk.iv, &ctrblk);
err = skcipher_walk_done(&walk, 0);
}
return err;
}
EXPORT_SYMBOL_GPL(glue_ctr_req_128bit);
static unsigned int __glue_xts_req_128bit(const struct common_glue_ctx *gctx,
void *ctx,
struct skcipher_walk *walk)
{
const unsigned int bsize = 128 / 8;
unsigned int nbytes = walk->nbytes;
u128 *src = walk->src.virt.addr;
u128 *dst = walk->dst.virt.addr;
unsigned int num_blocks, func_bytes;
unsigned int i;
/* Process multi-block batch */
for (i = 0; i < gctx->num_funcs; i++) {
num_blocks = gctx->funcs[i].num_blocks;
func_bytes = bsize * num_blocks;
if (nbytes >= func_bytes) {
do {
gctx->funcs[i].fn_u.xts(ctx, (u8 *)dst,
(const u8 *)src,
walk->iv);
src += num_blocks;
dst += num_blocks;
nbytes -= func_bytes;
} while (nbytes >= func_bytes);
if (nbytes < bsize)
goto done;
}
}
done:
return nbytes;
}
int glue_xts_req_128bit(const struct common_glue_ctx *gctx,
struct skcipher_request *req,
common_glue_func_t tweak_fn, void *tweak_ctx,
void *crypt_ctx, bool decrypt)
{
const bool cts = (req->cryptlen % XTS_BLOCK_SIZE);
const unsigned int bsize = 128 / 8;
struct skcipher_request subreq;
struct skcipher_walk walk;
bool fpu_enabled = false;
unsigned int nbytes, tail;
int err;
if (req->cryptlen < XTS_BLOCK_SIZE)
return -EINVAL;
if (unlikely(cts)) {
struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
tail = req->cryptlen % XTS_BLOCK_SIZE + XTS_BLOCK_SIZE;
skcipher_request_set_tfm(&subreq, tfm);
skcipher_request_set_callback(&subreq,
crypto_skcipher_get_flags(tfm),
NULL, NULL);
skcipher_request_set_crypt(&subreq, req->src, req->dst,
req->cryptlen - tail, req->iv);
req = &subreq;
}
err = skcipher_walk_virt(&walk, req, false);
nbytes = walk.nbytes;
if (err)
return err;
/* set minimum length to bsize, for tweak_fn */
fpu_enabled = glue_fpu_begin(bsize, gctx->fpu_blocks_limit,
&walk, fpu_enabled,
nbytes < bsize ? bsize : nbytes);
/* calculate first value of T */
tweak_fn(tweak_ctx, walk.iv, walk.iv);
while (nbytes) {
nbytes = __glue_xts_req_128bit(gctx, crypt_ctx, &walk);
err = skcipher_walk_done(&walk, nbytes);
nbytes = walk.nbytes;
}
if (unlikely(cts)) {
u8 *next_tweak, *final_tweak = req->iv;
struct scatterlist *src, *dst;
struct scatterlist s[2], d[2];
le128 b[2];
dst = src = scatterwalk_ffwd(s, req->src, req->cryptlen);
if (req->dst != req->src)
dst = scatterwalk_ffwd(d, req->dst, req->cryptlen);
if (decrypt) {
next_tweak = memcpy(b, req->iv, XTS_BLOCK_SIZE);
gf128mul_x_ble(b, b);
} else {
next_tweak = req->iv;
}
skcipher_request_set_crypt(&subreq, src, dst, XTS_BLOCK_SIZE,
next_tweak);
err = skcipher_walk_virt(&walk, req, false) ?:
skcipher_walk_done(&walk,
__glue_xts_req_128bit(gctx, crypt_ctx, &walk));
if (err)
goto out;
scatterwalk_map_and_copy(b, dst, 0, XTS_BLOCK_SIZE, 0);
memcpy(b + 1, b, tail - XTS_BLOCK_SIZE);
scatterwalk_map_and_copy(b, src, XTS_BLOCK_SIZE,
tail - XTS_BLOCK_SIZE, 0);
scatterwalk_map_and_copy(b, dst, 0, tail, 1);
skcipher_request_set_crypt(&subreq, dst, dst, XTS_BLOCK_SIZE,
final_tweak);
err = skcipher_walk_virt(&walk, req, false) ?:
skcipher_walk_done(&walk,
__glue_xts_req_128bit(gctx, crypt_ctx, &walk));
}
out:
glue_fpu_end(fpu_enabled);
return err;
}
EXPORT_SYMBOL_GPL(glue_xts_req_128bit);
void glue_xts_crypt_128bit_one(const void *ctx, u8 *dst, const u8 *src,
le128 *iv, common_glue_func_t fn)
{
le128 ivblk = *iv;
/* generate next IV */
gf128mul_x_ble(iv, &ivblk);
/* CC <- T xor C */
u128_xor((u128 *)dst, (const u128 *)src, (u128 *)&ivblk);
/* PP <- D(Key2,CC) */
fn(ctx, dst, dst);
/* P <- T xor PP */
u128_xor((u128 *)dst, (u128 *)dst, (u128 *)&ivblk);
}
EXPORT_SYMBOL_GPL(glue_xts_crypt_128bit_one);
MODULE_LICENSE("GPL");