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Commit 91652be5 authored by David Howells's avatar David Howells Committed by Herbert Xu
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[CRYPTO] pcbc: Add Propagated CBC template 



Add PCBC crypto template support as used by RxRPC.

Signed-Off-By: default avatarDavid Howells <dhowells@redhat.com>
Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
parent a28091ae

crypto/Kconfig

+9 −0
Original line number Diff line number Diff line
@@ -168,6 +168,15 @@ config CRYPTO_CBC 
	  CBC: Cipher Block Chaining mode

	  This block cipher algorithm is required for IPSec.



config CRYPTO_PCBC

	tristate "PCBC support"

	select CRYPTO_BLKCIPHER

	select CRYPTO_MANAGER

	default m

	help

	  PCBC: Propagating Cipher Block Chaining mode

	  This block cipher algorithm is required for RxRPC.



config CRYPTO_LRW

	tristate "LRW support (EXPERIMENTAL)"

	depends on EXPERIMENTAL

crypto/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -27,6 +27,7 @@ obj-$(CONFIG_CRYPTO_TGR192) += tgr192.o 
obj-$(CONFIG_CRYPTO_GF128MUL) += gf128mul.o

obj-$(CONFIG_CRYPTO_ECB) += ecb.o

obj-$(CONFIG_CRYPTO_CBC) += cbc.o

obj-$(CONFIG_CRYPTO_PCBC) += pcbc.o

obj-$(CONFIG_CRYPTO_LRW) += lrw.o

obj-$(CONFIG_CRYPTO_DES) += des.o

obj-$(CONFIG_CRYPTO_BLOWFISH) += blowfish.o

crypto/pcbc.c

0 → 100644
+348 −0
Original line number Diff line number Diff line 
/*

 * PCBC: Propagating Cipher Block Chaining mode

 *

 * Copyright (C) 2006 Red Hat, Inc. All Rights Reserved.

 * Written by David Howells (dhowells@redhat.com)

 *

 * Derived from cbc.c

 * - Copyright (c) 2006 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.

 *

 */



#include <crypto/algapi.h>

#include <linux/err.h>

#include <linux/init.h>

#include <linux/kernel.h>

#include <linux/module.h>

#include <linux/scatterlist.h>

#include <linux/slab.h>



struct crypto_pcbc_ctx {

	struct crypto_cipher *child;

	void (*xor)(u8 *dst, const u8 *src, unsigned int bs);

};



static int crypto_pcbc_setkey(struct crypto_tfm *parent, const u8 *key,

			      unsigned int keylen)

{

	struct crypto_pcbc_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 int crypto_pcbc_encrypt_segment(struct blkcipher_desc *desc,

				       struct blkcipher_walk *walk,

				       struct crypto_cipher *tfm,

				       void (*xor)(u8 *, const u8 *,

						   unsigned int))

{

	void (*fn)(struct crypto_tfm *, u8 *, const u8 *) =

		crypto_cipher_alg(tfm)->cia_encrypt;

	int bsize = crypto_cipher_blocksize(tfm);

	unsigned int nbytes = walk->nbytes;

	u8 *src = walk->src.virt.addr;

	u8 *dst = walk->dst.virt.addr;

	u8 *iv = walk->iv;



	do {

		xor(iv, src, bsize);

		fn(crypto_cipher_tfm(tfm), dst, iv);

		memcpy(iv, dst, bsize);

		xor(iv, src, bsize);



		src += bsize;

		dst += bsize;

	} while ((nbytes -= bsize) >= bsize);



	return nbytes;

}



static int crypto_pcbc_encrypt_inplace(struct blkcipher_desc *desc,

				       struct blkcipher_walk *walk,

				       struct crypto_cipher *tfm,

				       void (*xor)(u8 *, const u8 *,

						   unsigned int))

{

	void (*fn)(struct crypto_tfm *, u8 *, const u8 *) =

		crypto_cipher_alg(tfm)->cia_encrypt;

	int bsize = crypto_cipher_blocksize(tfm);

	unsigned int nbytes = walk->nbytes;

	u8 *src = walk->src.virt.addr;

	u8 *iv = walk->iv;

	u8 tmpbuf[bsize];



	do {

		memcpy(tmpbuf, src, bsize);

		xor(iv, tmpbuf, bsize);

		fn(crypto_cipher_tfm(tfm), src, iv);

		memcpy(iv, src, bsize);

		xor(iv, tmpbuf, bsize);



		src += bsize;

	} while ((nbytes -= bsize) >= bsize);



	memcpy(walk->iv, iv, bsize);



	return nbytes;

}



static int crypto_pcbc_encrypt(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_pcbc_ctx *ctx = crypto_blkcipher_ctx(tfm);

	struct crypto_cipher *child = ctx->child;

	void (*xor)(u8 *, const u8 *, unsigned int bs) = ctx->xor;

	int err;



	blkcipher_walk_init(&walk, dst, src, nbytes);

	err = blkcipher_walk_virt(desc, &walk);



	while ((nbytes = walk.nbytes)) {

		if (walk.src.virt.addr == walk.dst.virt.addr)

			nbytes = crypto_pcbc_encrypt_inplace(desc, &walk, child,

							     xor);

		else

			nbytes = crypto_pcbc_encrypt_segment(desc, &walk, child,

							     xor);

		err = blkcipher_walk_done(desc, &walk, nbytes);

	}



	return err;

}



static int crypto_pcbc_decrypt_segment(struct blkcipher_desc *desc,

				       struct blkcipher_walk *walk,

				       struct crypto_cipher *tfm,

				       void (*xor)(u8 *, const u8 *,

						   unsigned int))

{

	void (*fn)(struct crypto_tfm *, u8 *, const u8 *) =

		crypto_cipher_alg(tfm)->cia_decrypt;

	int bsize = crypto_cipher_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(crypto_cipher_tfm(tfm), dst, src);

		xor(dst, iv, bsize);

		memcpy(iv, src, bsize);

		xor(iv, dst, bsize);



		src += bsize;

		dst += bsize;

	} while ((nbytes -= bsize) >= bsize);



	memcpy(walk->iv, iv, bsize);



	return nbytes;

}



static int crypto_pcbc_decrypt_inplace(struct blkcipher_desc *desc,

				       struct blkcipher_walk *walk,

				       struct crypto_cipher *tfm,

				       void (*xor)(u8 *, const u8 *,

						   unsigned int))

{

	void (*fn)(struct crypto_tfm *, u8 *, const u8 *) =

		crypto_cipher_alg(tfm)->cia_decrypt;

	int bsize = crypto_cipher_blocksize(tfm);

	unsigned int nbytes = walk->nbytes;

	u8 *src = walk->src.virt.addr;

	u8 *iv = walk->iv;

	u8 tmpbuf[bsize];



	do {

		memcpy(tmpbuf, src, bsize);

		fn(crypto_cipher_tfm(tfm), src, src);

		xor(src, iv, bsize);

		memcpy(iv, tmpbuf, bsize);

		xor(iv, src, bsize);



		src += bsize;

	} while ((nbytes -= bsize) >= bsize);



	memcpy(walk->iv, iv, bsize);



	return nbytes;

}



static int crypto_pcbc_decrypt(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_pcbc_ctx *ctx = crypto_blkcipher_ctx(tfm);

	struct crypto_cipher *child = ctx->child;

	void (*xor)(u8 *, const u8 *, unsigned int bs) = ctx->xor;

	int err;



	blkcipher_walk_init(&walk, dst, src, nbytes);

	err = blkcipher_walk_virt(desc, &walk);



	while ((nbytes = walk.nbytes)) {

		if (walk.src.virt.addr == walk.dst.virt.addr)

			nbytes = crypto_pcbc_decrypt_inplace(desc, &walk, child,

							     xor);

		else

			nbytes = crypto_pcbc_decrypt_segment(desc, &walk, child,

							     xor);

		err = blkcipher_walk_done(desc, &walk, nbytes);

	}



	return err;

}



static void xor_byte(u8 *a, const u8 *b, unsigned int bs)

{

	do {

		*a++ ^= *b++;

	} while (--bs);

}



static void xor_quad(u8 *dst, const u8 *src, unsigned int bs)

{

	u32 *a = (u32 *)dst;

	u32 *b = (u32 *)src;



	do {

		*a++ ^= *b++;

	} while ((bs -= 4));

}



static void xor_64(u8 *a, const u8 *b, unsigned int bs)

{

	((u32 *)a)[0] ^= ((u32 *)b)[0];

	((u32 *)a)[1] ^= ((u32 *)b)[1];

}



static void xor_128(u8 *a, const u8 *b, unsigned int bs)

{

	((u32 *)a)[0] ^= ((u32 *)b)[0];

	((u32 *)a)[1] ^= ((u32 *)b)[1];

	((u32 *)a)[2] ^= ((u32 *)b)[2];

	((u32 *)a)[3] ^= ((u32 *)b)[3];

}



static int crypto_pcbc_init_tfm(struct crypto_tfm *tfm)

{

	struct crypto_instance *inst = (void *)tfm->__crt_alg;

	struct crypto_spawn *spawn = crypto_instance_ctx(inst);

	struct crypto_pcbc_ctx *ctx = crypto_tfm_ctx(tfm);



	switch (crypto_tfm_alg_blocksize(tfm)) {

	case 8:

		ctx->xor = xor_64;

		break;



	case 16:

		ctx->xor = xor_128;

		break;



	default:

		if (crypto_tfm_alg_blocksize(tfm) % 4)

			ctx->xor = xor_byte;

		else

			ctx->xor = xor_quad;

	}



	tfm = crypto_spawn_tfm(spawn);

	if (IS_ERR(tfm))

		return PTR_ERR(tfm);



	ctx->child = crypto_cipher_cast(tfm);

	return 0;

}



static void crypto_pcbc_exit_tfm(struct crypto_tfm *tfm)

{

	struct crypto_pcbc_ctx *ctx = crypto_tfm_ctx(tfm);

	crypto_free_cipher(ctx->child);

}



static struct crypto_instance *crypto_pcbc_alloc(void *param, unsigned int len)

{

	struct crypto_instance *inst;

	struct crypto_alg *alg;



	alg = crypto_get_attr_alg(param, len, CRYPTO_ALG_TYPE_CIPHER,

				  CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_ASYNC);

	if (IS_ERR(alg))

		return ERR_PTR(PTR_ERR(alg));



	inst = crypto_alloc_instance("pcbc", alg);

	if (IS_ERR(inst))

		goto out_put_alg;



	inst->alg.cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER;

	inst->alg.cra_priority = alg->cra_priority;

	inst->alg.cra_blocksize = alg->cra_blocksize;

	inst->alg.cra_alignmask = alg->cra_alignmask;

	inst->alg.cra_type = &crypto_blkcipher_type;



	if (!(alg->cra_blocksize % 4))

		inst->alg.cra_alignmask |= 3;

	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_pcbc_ctx);



	inst->alg.cra_init = crypto_pcbc_init_tfm;

	inst->alg.cra_exit = crypto_pcbc_exit_tfm;



	inst->alg.cra_blkcipher.setkey = crypto_pcbc_setkey;

	inst->alg.cra_blkcipher.encrypt = crypto_pcbc_encrypt;

	inst->alg.cra_blkcipher.decrypt = crypto_pcbc_decrypt;



out_put_alg:

	crypto_mod_put(alg);

	return inst;

}



static void crypto_pcbc_free(struct crypto_instance *inst)

{

	crypto_drop_spawn(crypto_instance_ctx(inst));

	kfree(inst);

}



static struct crypto_template crypto_pcbc_tmpl = {

	.name = "pcbc",

	.alloc = crypto_pcbc_alloc,

	.free = crypto_pcbc_free,

	.module = THIS_MODULE,

};



static int __init crypto_pcbc_module_init(void)

{

	return crypto_register_template(&crypto_pcbc_tmpl);

}



static void __exit crypto_pcbc_module_exit(void)

{

	crypto_unregister_template(&crypto_pcbc_tmpl);

}



module_init(crypto_pcbc_module_init);

module_exit(crypto_pcbc_module_exit);



MODULE_LICENSE("GPL");

MODULE_DESCRIPTION("PCBC block cipher algorithm");