mirror of
https://github.com/torvalds/linux
synced 2024-11-05 18:23:50 +00:00
d73d67fbcb
In the quest to remove all stack VLA usage from the kernel[1], this uses the upper bounds on blocksize. Since this is always a cipher blocksize, use the existing cipher max blocksize. [1] https://lkml.kernel.org/r/CA+55aFzCG-zNmZwX4A2FQpadafLfEzK6CC=qPXydAacU1RqZWA@mail.gmail.com Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
146 lines
3.5 KiB
C
146 lines
3.5 KiB
C
/*
|
|
* CBC: Cipher Block Chaining mode
|
|
*
|
|
* Copyright (c) 2016 Herbert Xu <herbert@gondor.apana.org.au>
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify it
|
|
* under the terms of the GNU General Public License as published by the Free
|
|
* Software Foundation; either version 2 of the License, or (at your option)
|
|
* any later version.
|
|
*
|
|
*/
|
|
|
|
#ifndef _CRYPTO_CBC_H
|
|
#define _CRYPTO_CBC_H
|
|
|
|
#include <crypto/internal/skcipher.h>
|
|
#include <linux/string.h>
|
|
#include <linux/types.h>
|
|
|
|
static inline int crypto_cbc_encrypt_segment(
|
|
struct skcipher_walk *walk, struct crypto_skcipher *tfm,
|
|
void (*fn)(struct crypto_skcipher *, const u8 *, u8 *))
|
|
{
|
|
unsigned int bsize = crypto_skcipher_blocksize(tfm);
|
|
unsigned int nbytes = walk->nbytes;
|
|
u8 *src = walk->src.virt.addr;
|
|
u8 *dst = walk->dst.virt.addr;
|
|
u8 *iv = walk->iv;
|
|
|
|
do {
|
|
crypto_xor(iv, src, bsize);
|
|
fn(tfm, iv, dst);
|
|
memcpy(iv, dst, bsize);
|
|
|
|
src += bsize;
|
|
dst += bsize;
|
|
} while ((nbytes -= bsize) >= bsize);
|
|
|
|
return nbytes;
|
|
}
|
|
|
|
static inline int crypto_cbc_encrypt_inplace(
|
|
struct skcipher_walk *walk, struct crypto_skcipher *tfm,
|
|
void (*fn)(struct crypto_skcipher *, const u8 *, u8 *))
|
|
{
|
|
unsigned int bsize = crypto_skcipher_blocksize(tfm);
|
|
unsigned int nbytes = walk->nbytes;
|
|
u8 *src = walk->src.virt.addr;
|
|
u8 *iv = walk->iv;
|
|
|
|
do {
|
|
crypto_xor(src, iv, bsize);
|
|
fn(tfm, src, src);
|
|
iv = src;
|
|
|
|
src += bsize;
|
|
} while ((nbytes -= bsize) >= bsize);
|
|
|
|
memcpy(walk->iv, iv, bsize);
|
|
|
|
return nbytes;
|
|
}
|
|
|
|
static inline int crypto_cbc_encrypt_walk(struct skcipher_request *req,
|
|
void (*fn)(struct crypto_skcipher *,
|
|
const u8 *, u8 *))
|
|
{
|
|
struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
|
|
struct skcipher_walk walk;
|
|
int err;
|
|
|
|
err = skcipher_walk_virt(&walk, req, false);
|
|
|
|
while (walk.nbytes) {
|
|
if (walk.src.virt.addr == walk.dst.virt.addr)
|
|
err = crypto_cbc_encrypt_inplace(&walk, tfm, fn);
|
|
else
|
|
err = crypto_cbc_encrypt_segment(&walk, tfm, fn);
|
|
err = skcipher_walk_done(&walk, err);
|
|
}
|
|
|
|
return err;
|
|
}
|
|
|
|
static inline int crypto_cbc_decrypt_segment(
|
|
struct skcipher_walk *walk, struct crypto_skcipher *tfm,
|
|
void (*fn)(struct crypto_skcipher *, const u8 *, u8 *))
|
|
{
|
|
unsigned int bsize = crypto_skcipher_blocksize(tfm);
|
|
unsigned int nbytes = walk->nbytes;
|
|
u8 *src = walk->src.virt.addr;
|
|
u8 *dst = walk->dst.virt.addr;
|
|
u8 *iv = walk->iv;
|
|
|
|
do {
|
|
fn(tfm, src, dst);
|
|
crypto_xor(dst, iv, bsize);
|
|
iv = src;
|
|
|
|
src += bsize;
|
|
dst += bsize;
|
|
} while ((nbytes -= bsize) >= bsize);
|
|
|
|
memcpy(walk->iv, iv, bsize);
|
|
|
|
return nbytes;
|
|
}
|
|
|
|
static inline int crypto_cbc_decrypt_inplace(
|
|
struct skcipher_walk *walk, struct crypto_skcipher *tfm,
|
|
void (*fn)(struct crypto_skcipher *, const u8 *, u8 *))
|
|
{
|
|
unsigned int bsize = crypto_skcipher_blocksize(tfm);
|
|
unsigned int nbytes = walk->nbytes;
|
|
u8 *src = walk->src.virt.addr;
|
|
u8 last_iv[MAX_CIPHER_BLOCKSIZE];
|
|
|
|
/* Start of the last block. */
|
|
src += nbytes - (nbytes & (bsize - 1)) - bsize;
|
|
memcpy(last_iv, src, bsize);
|
|
|
|
for (;;) {
|
|
fn(tfm, src, src);
|
|
if ((nbytes -= bsize) < bsize)
|
|
break;
|
|
crypto_xor(src, src - bsize, bsize);
|
|
src -= bsize;
|
|
}
|
|
|
|
crypto_xor(src, walk->iv, bsize);
|
|
memcpy(walk->iv, last_iv, bsize);
|
|
|
|
return nbytes;
|
|
}
|
|
|
|
static inline int crypto_cbc_decrypt_blocks(
|
|
struct skcipher_walk *walk, struct crypto_skcipher *tfm,
|
|
void (*fn)(struct crypto_skcipher *, const u8 *, u8 *))
|
|
{
|
|
if (walk->src.virt.addr == walk->dst.virt.addr)
|
|
return crypto_cbc_decrypt_inplace(walk, tfm, fn);
|
|
else
|
|
return crypto_cbc_decrypt_segment(walk, tfm, fn);
|
|
}
|
|
|
|
#endif /* _CRYPTO_CBC_H */
|