66 lines
1.4 KiB
C
66 lines
1.4 KiB
C
/* SPDX-License-Identifier: GPL-2.0-or-later */
|
|
/*
|
|
* CTR: Counter mode
|
|
*
|
|
* Copyright (c) 2007 Herbert Xu <herbert@gondor.apana.org.au>
|
|
*/
|
|
|
|
#ifndef _CRYPTO_CTR_H
|
|
#define _CRYPTO_CTR_H
|
|
|
|
#include <crypto/algapi.h>
|
|
#include <crypto/internal/skcipher.h>
|
|
#include <linux/string.h>
|
|
#include <linux/types.h>
|
|
|
|
#define CTR_RFC3686_NONCE_SIZE 4
|
|
#define CTR_RFC3686_IV_SIZE 8
|
|
#define CTR_RFC3686_BLOCK_SIZE 16
|
|
|
|
static inline int crypto_ctr_encrypt_walk(struct skcipher_request *req,
|
|
void (*fn)(struct crypto_skcipher *,
|
|
const u8 *, u8 *))
|
|
{
|
|
struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
|
|
int blocksize = crypto_skcipher_chunksize(tfm);
|
|
u8 buf[MAX_CIPHER_BLOCKSIZE];
|
|
struct skcipher_walk walk;
|
|
int err;
|
|
|
|
/* avoid integer division due to variable blocksize parameter */
|
|
if (WARN_ON_ONCE(!is_power_of_2(blocksize)))
|
|
return -EINVAL;
|
|
|
|
err = skcipher_walk_virt(&walk, req, false);
|
|
|
|
while (walk.nbytes > 0) {
|
|
u8 *dst = walk.dst.virt.addr;
|
|
u8 *src = walk.src.virt.addr;
|
|
int nbytes = walk.nbytes;
|
|
int tail = 0;
|
|
|
|
if (nbytes < walk.total) {
|
|
tail = walk.nbytes & (blocksize - 1);
|
|
nbytes -= tail;
|
|
}
|
|
|
|
do {
|
|
int bsize = min(nbytes, blocksize);
|
|
|
|
fn(tfm, walk.iv, buf);
|
|
|
|
crypto_xor_cpy(dst, src, buf, bsize);
|
|
crypto_inc(walk.iv, blocksize);
|
|
|
|
dst += bsize;
|
|
src += bsize;
|
|
nbytes -= bsize;
|
|
} while (nbytes > 0);
|
|
|
|
err = skcipher_walk_done(&walk, tail);
|
|
}
|
|
return err;
|
|
}
|
|
|
|
#endif /* _CRYPTO_CTR_H */
|