linux/crypto/ctr.c
Jussi Kivilinna 69d3150cfc crypto: ctr - make rfc3686 asynchronous block cipher
Some hardware crypto drivers register asynchronous ctr(aes), which is left
unused in IPSEC because rfc3686 template only supports synchronous block
ciphers. Some other drivers register rfc3686(ctr(aes)) to workaround this
limitation but not all.

This patch changes rfc3686 to use asynchronous block ciphers, to allow async
ctr(aes) algorithms to be utilized automatically by IPSEC.

Signed-off-by: Jussi Kivilinna <jussi.kivilinna@mbnet.fi>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
2013-01-08 07:03:04 +01:00

472 lines
12 KiB
C

/*
* CTR: Counter mode
*
* (C) Copyright IBM Corp. 2007 - Joy Latten <latten@us.ibm.com>
*
* 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.
*
*/
#include <crypto/algapi.h>
#include <crypto/ctr.h>
#include <crypto/internal/skcipher.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/random.h>
#include <linux/scatterlist.h>
#include <linux/slab.h>
struct crypto_ctr_ctx {
struct crypto_cipher *child;
};
struct crypto_rfc3686_ctx {
struct crypto_ablkcipher *child;
u8 nonce[CTR_RFC3686_NONCE_SIZE];
};
struct crypto_rfc3686_req_ctx {
u8 iv[CTR_RFC3686_BLOCK_SIZE];
struct ablkcipher_request subreq CRYPTO_MINALIGN_ATTR;
};
static int crypto_ctr_setkey(struct crypto_tfm *parent, const u8 *key,
unsigned int keylen)
{
struct crypto_ctr_ctx *ctx = crypto_tfm_ctx(parent);
struct crypto_cipher *child = ctx->child;
int err;
crypto_cipher_clear_flags(child, CRYPTO_TFM_REQ_MASK);
crypto_cipher_set_flags(child, crypto_tfm_get_flags(parent) &
CRYPTO_TFM_REQ_MASK);
err = crypto_cipher_setkey(child, key, keylen);
crypto_tfm_set_flags(parent, crypto_cipher_get_flags(child) &
CRYPTO_TFM_RES_MASK);
return err;
}
static void crypto_ctr_crypt_final(struct blkcipher_walk *walk,
struct crypto_cipher *tfm)
{
unsigned int bsize = crypto_cipher_blocksize(tfm);
unsigned long alignmask = crypto_cipher_alignmask(tfm);
u8 *ctrblk = walk->iv;
u8 tmp[bsize + alignmask];
u8 *keystream = PTR_ALIGN(tmp + 0, alignmask + 1);
u8 *src = walk->src.virt.addr;
u8 *dst = walk->dst.virt.addr;
unsigned int nbytes = walk->nbytes;
crypto_cipher_encrypt_one(tfm, keystream, ctrblk);
crypto_xor(keystream, src, nbytes);
memcpy(dst, keystream, nbytes);
crypto_inc(ctrblk, bsize);
}
static int crypto_ctr_crypt_segment(struct blkcipher_walk *walk,
struct crypto_cipher *tfm)
{
void (*fn)(struct crypto_tfm *, u8 *, const u8 *) =
crypto_cipher_alg(tfm)->cia_encrypt;
unsigned int bsize = crypto_cipher_blocksize(tfm);
u8 *ctrblk = walk->iv;
u8 *src = walk->src.virt.addr;
u8 *dst = walk->dst.virt.addr;
unsigned int nbytes = walk->nbytes;
do {
/* create keystream */
fn(crypto_cipher_tfm(tfm), dst, ctrblk);
crypto_xor(dst, src, bsize);
/* increment counter in counterblock */
crypto_inc(ctrblk, bsize);
src += bsize;
dst += bsize;
} while ((nbytes -= bsize) >= bsize);
return nbytes;
}
static int crypto_ctr_crypt_inplace(struct blkcipher_walk *walk,
struct crypto_cipher *tfm)
{
void (*fn)(struct crypto_tfm *, u8 *, const u8 *) =
crypto_cipher_alg(tfm)->cia_encrypt;
unsigned int bsize = crypto_cipher_blocksize(tfm);
unsigned long alignmask = crypto_cipher_alignmask(tfm);
unsigned int nbytes = walk->nbytes;
u8 *ctrblk = walk->iv;
u8 *src = walk->src.virt.addr;
u8 tmp[bsize + alignmask];
u8 *keystream = PTR_ALIGN(tmp + 0, alignmask + 1);
do {
/* create keystream */
fn(crypto_cipher_tfm(tfm), keystream, ctrblk);
crypto_xor(src, keystream, bsize);
/* increment counter in counterblock */
crypto_inc(ctrblk, bsize);
src += bsize;
} while ((nbytes -= bsize) >= bsize);
return nbytes;
}
static int crypto_ctr_crypt(struct blkcipher_desc *desc,
struct scatterlist *dst, struct scatterlist *src,
unsigned int nbytes)
{
struct blkcipher_walk walk;
struct crypto_blkcipher *tfm = desc->tfm;
struct crypto_ctr_ctx *ctx = crypto_blkcipher_ctx(tfm);
struct crypto_cipher *child = ctx->child;
unsigned int bsize = crypto_cipher_blocksize(child);
int err;
blkcipher_walk_init(&walk, dst, src, nbytes);
err = blkcipher_walk_virt_block(desc, &walk, bsize);
while (walk.nbytes >= bsize) {
if (walk.src.virt.addr == walk.dst.virt.addr)
nbytes = crypto_ctr_crypt_inplace(&walk, child);
else
nbytes = crypto_ctr_crypt_segment(&walk, child);
err = blkcipher_walk_done(desc, &walk, nbytes);
}
if (walk.nbytes) {
crypto_ctr_crypt_final(&walk, child);
err = blkcipher_walk_done(desc, &walk, 0);
}
return err;
}
static int crypto_ctr_init_tfm(struct crypto_tfm *tfm)
{
struct crypto_instance *inst = (void *)tfm->__crt_alg;
struct crypto_spawn *spawn = crypto_instance_ctx(inst);
struct crypto_ctr_ctx *ctx = crypto_tfm_ctx(tfm);
struct crypto_cipher *cipher;
cipher = crypto_spawn_cipher(spawn);
if (IS_ERR(cipher))
return PTR_ERR(cipher);
ctx->child = cipher;
return 0;
}
static void crypto_ctr_exit_tfm(struct crypto_tfm *tfm)
{
struct crypto_ctr_ctx *ctx = crypto_tfm_ctx(tfm);
crypto_free_cipher(ctx->child);
}
static struct crypto_instance *crypto_ctr_alloc(struct rtattr **tb)
{
struct crypto_instance *inst;
struct crypto_alg *alg;
int err;
err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_BLKCIPHER);
if (err)
return ERR_PTR(err);
alg = crypto_attr_alg(tb[1], CRYPTO_ALG_TYPE_CIPHER,
CRYPTO_ALG_TYPE_MASK);
if (IS_ERR(alg))
return ERR_CAST(alg);
/* Block size must be >= 4 bytes. */
err = -EINVAL;
if (alg->cra_blocksize < 4)
goto out_put_alg;
/* If this is false we'd fail the alignment of crypto_inc. */
if (alg->cra_blocksize % 4)
goto out_put_alg;
inst = crypto_alloc_instance("ctr", alg);
if (IS_ERR(inst))
goto out;
inst->alg.cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER;
inst->alg.cra_priority = alg->cra_priority;
inst->alg.cra_blocksize = 1;
inst->alg.cra_alignmask = alg->cra_alignmask | (__alignof__(u32) - 1);
inst->alg.cra_type = &crypto_blkcipher_type;
inst->alg.cra_blkcipher.ivsize = alg->cra_blocksize;
inst->alg.cra_blkcipher.min_keysize = alg->cra_cipher.cia_min_keysize;
inst->alg.cra_blkcipher.max_keysize = alg->cra_cipher.cia_max_keysize;
inst->alg.cra_ctxsize = sizeof(struct crypto_ctr_ctx);
inst->alg.cra_init = crypto_ctr_init_tfm;
inst->alg.cra_exit = crypto_ctr_exit_tfm;
inst->alg.cra_blkcipher.setkey = crypto_ctr_setkey;
inst->alg.cra_blkcipher.encrypt = crypto_ctr_crypt;
inst->alg.cra_blkcipher.decrypt = crypto_ctr_crypt;
inst->alg.cra_blkcipher.geniv = "chainiv";
out:
crypto_mod_put(alg);
return inst;
out_put_alg:
inst = ERR_PTR(err);
goto out;
}
static void crypto_ctr_free(struct crypto_instance *inst)
{
crypto_drop_spawn(crypto_instance_ctx(inst));
kfree(inst);
}
static struct crypto_template crypto_ctr_tmpl = {
.name = "ctr",
.alloc = crypto_ctr_alloc,
.free = crypto_ctr_free,
.module = THIS_MODULE,
};
static int crypto_rfc3686_setkey(struct crypto_ablkcipher *parent,
const u8 *key, unsigned int keylen)
{
struct crypto_rfc3686_ctx *ctx = crypto_ablkcipher_ctx(parent);
struct crypto_ablkcipher *child = ctx->child;
int err;
/* the nonce is stored in bytes at end of key */
if (keylen < CTR_RFC3686_NONCE_SIZE)
return -EINVAL;
memcpy(ctx->nonce, key + (keylen - CTR_RFC3686_NONCE_SIZE),
CTR_RFC3686_NONCE_SIZE);
keylen -= CTR_RFC3686_NONCE_SIZE;
crypto_ablkcipher_clear_flags(child, CRYPTO_TFM_REQ_MASK);
crypto_ablkcipher_set_flags(child, crypto_ablkcipher_get_flags(parent) &
CRYPTO_TFM_REQ_MASK);
err = crypto_ablkcipher_setkey(child, key, keylen);
crypto_ablkcipher_set_flags(parent, crypto_ablkcipher_get_flags(child) &
CRYPTO_TFM_RES_MASK);
return err;
}
static int crypto_rfc3686_crypt(struct ablkcipher_request *req)
{
struct crypto_ablkcipher *tfm = crypto_ablkcipher_reqtfm(req);
struct crypto_rfc3686_ctx *ctx = crypto_ablkcipher_ctx(tfm);
struct crypto_ablkcipher *child = ctx->child;
unsigned long align = crypto_ablkcipher_alignmask(tfm);
struct crypto_rfc3686_req_ctx *rctx =
(void *)PTR_ALIGN((u8 *)ablkcipher_request_ctx(req), align + 1);
struct ablkcipher_request *subreq = &rctx->subreq;
u8 *iv = rctx->iv;
/* set up counter block */
memcpy(iv, ctx->nonce, CTR_RFC3686_NONCE_SIZE);
memcpy(iv + CTR_RFC3686_NONCE_SIZE, req->info, CTR_RFC3686_IV_SIZE);
/* initialize counter portion of counter block */
*(__be32 *)(iv + CTR_RFC3686_NONCE_SIZE + CTR_RFC3686_IV_SIZE) =
cpu_to_be32(1);
ablkcipher_request_set_tfm(subreq, child);
ablkcipher_request_set_callback(subreq, req->base.flags,
req->base.complete, req->base.data);
ablkcipher_request_set_crypt(subreq, req->src, req->dst, req->nbytes,
iv);
return crypto_ablkcipher_encrypt(subreq);
}
static int crypto_rfc3686_init_tfm(struct crypto_tfm *tfm)
{
struct crypto_instance *inst = (void *)tfm->__crt_alg;
struct crypto_skcipher_spawn *spawn = crypto_instance_ctx(inst);
struct crypto_rfc3686_ctx *ctx = crypto_tfm_ctx(tfm);
struct crypto_ablkcipher *cipher;
unsigned long align;
cipher = crypto_spawn_skcipher(spawn);
if (IS_ERR(cipher))
return PTR_ERR(cipher);
ctx->child = cipher;
align = crypto_tfm_alg_alignmask(tfm);
align &= ~(crypto_tfm_ctx_alignment() - 1);
tfm->crt_ablkcipher.reqsize = align +
sizeof(struct crypto_rfc3686_req_ctx) +
crypto_ablkcipher_reqsize(cipher);
return 0;
}
static void crypto_rfc3686_exit_tfm(struct crypto_tfm *tfm)
{
struct crypto_rfc3686_ctx *ctx = crypto_tfm_ctx(tfm);
crypto_free_ablkcipher(ctx->child);
}
static struct crypto_instance *crypto_rfc3686_alloc(struct rtattr **tb)
{
struct crypto_attr_type *algt;
struct crypto_instance *inst;
struct crypto_alg *alg;
struct crypto_skcipher_spawn *spawn;
const char *cipher_name;
int err;
algt = crypto_get_attr_type(tb);
err = PTR_ERR(algt);
if (IS_ERR(algt))
return ERR_PTR(err);
if ((algt->type ^ CRYPTO_ALG_TYPE_BLKCIPHER) & algt->mask)
return ERR_PTR(-EINVAL);
cipher_name = crypto_attr_alg_name(tb[1]);
err = PTR_ERR(cipher_name);
if (IS_ERR(cipher_name))
return ERR_PTR(err);
inst = kzalloc(sizeof(*inst) + sizeof(*spawn), GFP_KERNEL);
if (!inst)
return ERR_PTR(-ENOMEM);
spawn = crypto_instance_ctx(inst);
crypto_set_skcipher_spawn(spawn, inst);
err = crypto_grab_skcipher(spawn, cipher_name, 0,
crypto_requires_sync(algt->type,
algt->mask));
if (err)
goto err_free_inst;
alg = crypto_skcipher_spawn_alg(spawn);
/* We only support 16-byte blocks. */
err = -EINVAL;
if (alg->cra_ablkcipher.ivsize != CTR_RFC3686_BLOCK_SIZE)
goto err_drop_spawn;
/* Not a stream cipher? */
if (alg->cra_blocksize != 1)
goto err_drop_spawn;
err = -ENAMETOOLONG;
if (snprintf(inst->alg.cra_name, CRYPTO_MAX_ALG_NAME, "rfc3686(%s)",
alg->cra_name) >= CRYPTO_MAX_ALG_NAME)
goto err_drop_spawn;
if (snprintf(inst->alg.cra_driver_name, CRYPTO_MAX_ALG_NAME,
"rfc3686(%s)", alg->cra_driver_name) >=
CRYPTO_MAX_ALG_NAME)
goto err_drop_spawn;
inst->alg.cra_priority = alg->cra_priority;
inst->alg.cra_blocksize = 1;
inst->alg.cra_alignmask = alg->cra_alignmask;
inst->alg.cra_flags = CRYPTO_ALG_TYPE_ABLKCIPHER |
(alg->cra_flags & CRYPTO_ALG_ASYNC);
inst->alg.cra_type = &crypto_ablkcipher_type;
inst->alg.cra_ablkcipher.ivsize = CTR_RFC3686_IV_SIZE;
inst->alg.cra_ablkcipher.min_keysize =
alg->cra_ablkcipher.min_keysize + CTR_RFC3686_NONCE_SIZE;
inst->alg.cra_ablkcipher.max_keysize =
alg->cra_ablkcipher.max_keysize + CTR_RFC3686_NONCE_SIZE;
inst->alg.cra_ablkcipher.geniv = "seqiv";
inst->alg.cra_ablkcipher.setkey = crypto_rfc3686_setkey;
inst->alg.cra_ablkcipher.encrypt = crypto_rfc3686_crypt;
inst->alg.cra_ablkcipher.decrypt = crypto_rfc3686_crypt;
inst->alg.cra_ctxsize = sizeof(struct crypto_rfc3686_ctx);
inst->alg.cra_init = crypto_rfc3686_init_tfm;
inst->alg.cra_exit = crypto_rfc3686_exit_tfm;
return inst;
err_drop_spawn:
crypto_drop_skcipher(spawn);
err_free_inst:
kfree(inst);
return ERR_PTR(err);
}
static void crypto_rfc3686_free(struct crypto_instance *inst)
{
struct crypto_skcipher_spawn *spawn = crypto_instance_ctx(inst);
crypto_drop_skcipher(spawn);
kfree(inst);
}
static struct crypto_template crypto_rfc3686_tmpl = {
.name = "rfc3686",
.alloc = crypto_rfc3686_alloc,
.free = crypto_rfc3686_free,
.module = THIS_MODULE,
};
static int __init crypto_ctr_module_init(void)
{
int err;
err = crypto_register_template(&crypto_ctr_tmpl);
if (err)
goto out;
err = crypto_register_template(&crypto_rfc3686_tmpl);
if (err)
goto out_drop_ctr;
out:
return err;
out_drop_ctr:
crypto_unregister_template(&crypto_ctr_tmpl);
goto out;
}
static void __exit crypto_ctr_module_exit(void)
{
crypto_unregister_template(&crypto_rfc3686_tmpl);
crypto_unregister_template(&crypto_ctr_tmpl);
}
module_init(crypto_ctr_module_init);
module_exit(crypto_ctr_module_exit);
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("CTR Counter block mode");
MODULE_ALIAS("rfc3686");