Commit 6b611d98 authored by Eric Biggers's avatar Eric Biggers Committed by Herbert Xu
Browse files

crypto: keywrap - convert to skcipher API 



Convert the keywrap template from the deprecated "blkcipher" API to the
"skcipher" API, taking advantage of skcipher_alloc_instance_simple() to
simplify it considerably.

Cc: Stephan Mueller <smueller@chronox.de>
Signed-off-by: default avatarEric Biggers <ebiggers@google.com>
Reviewed-by: default avatarStephan Mueller <smueller@chronox.de>
Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
parent 52e9368f

crypto/keywrap.c

+65 −133
Original line number Diff line number Diff line
@@ -56,7 +56,7 @@ 
 *	u8 *iv = data;

 *	u8 *pt = data + crypto_skcipher_ivsize(tfm);

 *		<ensure that pt contains the plaintext of size ptlen>

 *	sg_init_one(&sg, ptdata, ptlen);

 *	sg_init_one(&sg, pt, ptlen);

 *	skcipher_request_set_crypt(req, &sg, &sg, ptlen, iv);

 *

 *	==> After encryption, data now contains full KW result as per SP800-38F.
@@ -70,8 +70,8 @@ 
 *	u8 *iv = data;

 *	u8 *ct = data + crypto_skcipher_ivsize(tfm);

 *	unsigned int ctlen = datalen - crypto_skcipher_ivsize(tfm);

 *	sg_init_one(&sg, ctdata, ctlen);

 *	skcipher_request_set_crypt(req, &sg, &sg, ptlen, iv);

 *	sg_init_one(&sg, ct, ctlen);

 *	skcipher_request_set_crypt(req, &sg, &sg, ctlen, iv);

 *

 *	==> After decryption (which hopefully does not return EBADMSG), the ct

 *	pointer now points to the plaintext of size ctlen.
@@ -87,10 +87,6 @@ 
#include <crypto/scatterwalk.h>

#include <crypto/internal/skcipher.h>



struct crypto_kw_ctx {

	struct crypto_cipher *child;

};



struct crypto_kw_block {

#define SEMIBSIZE 8

	__be64 A;
@@ -124,16 +120,13 @@ static void crypto_kw_scatterlist_ff(struct scatter_walk *walk, 
	}

}



static int crypto_kw_decrypt(struct blkcipher_desc *desc,

			     struct scatterlist *dst, struct scatterlist *src,

			     unsigned int nbytes)

static int crypto_kw_decrypt(struct skcipher_request *req)

{

	struct crypto_blkcipher *tfm = desc->tfm;

	struct crypto_kw_ctx *ctx = crypto_blkcipher_ctx(tfm);

	struct crypto_cipher *child = ctx->child;

	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);

	struct crypto_cipher *cipher = skcipher_cipher_simple(tfm);

	struct crypto_kw_block block;

	struct scatterlist *lsrc, *ldst;

	u64 t = 6 * ((nbytes) >> 3);

	struct scatterlist *src, *dst;

	u64 t = 6 * ((req->cryptlen) >> 3);

	unsigned int i;

	int ret = 0;
@@ -141,27 +134,27 @@ static int crypto_kw_decrypt(struct blkcipher_desc *desc, 
	 * Require at least 2 semiblocks (note, the 3rd semiblock that is

	 * required by SP800-38F is the IV.

	 */

	if (nbytes < (2 * SEMIBSIZE) || nbytes % SEMIBSIZE)

	if (req->cryptlen < (2 * SEMIBSIZE) || req->cryptlen % SEMIBSIZE)

		return -EINVAL;



	/* Place the IV into block A */

	memcpy(&block.A, desc->info, SEMIBSIZE);

	memcpy(&block.A, req->iv, SEMIBSIZE);



	/*

	 * src scatterlist is read-only. dst scatterlist is r/w. During the

	 * first loop, lsrc points to src and ldst to dst. For any

	 * subsequent round, the code operates on dst only.

	 * first loop, src points to req->src and dst to req->dst. For any

	 * subsequent round, the code operates on req->dst only.

	 */

	lsrc = src;

	ldst = dst;

	src = req->src;

	dst = req->dst;



	for (i = 0; i < 6; i++) {

		struct scatter_walk src_walk, dst_walk;

		unsigned int tmp_nbytes = nbytes;

		unsigned int nbytes = req->cryptlen;



		while (tmp_nbytes) {

			/* move pointer by tmp_nbytes in the SGL */

			crypto_kw_scatterlist_ff(&src_walk, lsrc, tmp_nbytes);

		while (nbytes) {

			/* move pointer by nbytes in the SGL */

			crypto_kw_scatterlist_ff(&src_walk, src, nbytes);

			/* get the source block */

			scatterwalk_copychunks(&block.R, &src_walk, SEMIBSIZE,

					       false);
@@ -170,21 +163,21 @@ static int crypto_kw_decrypt(struct blkcipher_desc *desc, 
			block.A ^= cpu_to_be64(t);

			t--;

			/* perform KW operation: decrypt block */

			crypto_cipher_decrypt_one(child, (u8*)&block,

			crypto_cipher_decrypt_one(cipher, (u8 *)&block,

						  (u8 *)&block);



			/* move pointer by tmp_nbytes in the SGL */

			crypto_kw_scatterlist_ff(&dst_walk, ldst, tmp_nbytes);

			/* move pointer by nbytes in the SGL */

			crypto_kw_scatterlist_ff(&dst_walk, dst, nbytes);

			/* Copy block->R into place */

			scatterwalk_copychunks(&block.R, &dst_walk, SEMIBSIZE,

					       true);



			tmp_nbytes -= SEMIBSIZE;

			nbytes -= SEMIBSIZE;

		}



		/* we now start to operate on the dst SGL only */

		lsrc = dst;

		ldst = dst;

		src = req->dst;

		dst = req->dst;

	}



	/* Perform authentication check */
@@ -196,15 +189,12 @@ static int crypto_kw_decrypt(struct blkcipher_desc *desc, 
	return ret;

}



static int crypto_kw_encrypt(struct blkcipher_desc *desc,

			     struct scatterlist *dst, struct scatterlist *src,

			     unsigned int nbytes)

static int crypto_kw_encrypt(struct skcipher_request *req)

{

	struct crypto_blkcipher *tfm = desc->tfm;

	struct crypto_kw_ctx *ctx = crypto_blkcipher_ctx(tfm);

	struct crypto_cipher *child = ctx->child;

	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);

	struct crypto_cipher *cipher = skcipher_cipher_simple(tfm);

	struct crypto_kw_block block;

	struct scatterlist *lsrc, *ldst;

	struct scatterlist *src, *dst;

	u64 t = 1;

	unsigned int i;
@@ -214,7 +204,7 @@ static int crypto_kw_encrypt(struct blkcipher_desc *desc, 
	 * This means that the dst memory must be one semiblock larger than src.

	 * Also ensure that the given data is aligned to semiblock.

	 */

	if (nbytes < (2 * SEMIBSIZE) || nbytes % SEMIBSIZE)

	if (req->cryptlen < (2 * SEMIBSIZE) || req->cryptlen % SEMIBSIZE)

		return -EINVAL;



	/*
@@ -225,26 +215,26 @@ static int crypto_kw_encrypt(struct blkcipher_desc *desc, 


	/*

	 * src scatterlist is read-only. dst scatterlist is r/w. During the

	 * first loop, lsrc points to src and ldst to dst. For any

	 * subsequent round, the code operates on dst only.

	 * first loop, src points to req->src and dst to req->dst. For any

	 * subsequent round, the code operates on req->dst only.

	 */

	lsrc = src;

	ldst = dst;

	src = req->src;

	dst = req->dst;



	for (i = 0; i < 6; i++) {

		struct scatter_walk src_walk, dst_walk;

		unsigned int tmp_nbytes = nbytes;

		unsigned int nbytes = req->cryptlen;



		scatterwalk_start(&src_walk, lsrc);

		scatterwalk_start(&dst_walk, ldst);

		scatterwalk_start(&src_walk, src);

		scatterwalk_start(&dst_walk, dst);



		while (tmp_nbytes) {

		while (nbytes) {

			/* get the source block */

			scatterwalk_copychunks(&block.R, &src_walk, SEMIBSIZE,

					       false);



			/* perform KW operation: encrypt block */

			crypto_cipher_encrypt_one(child, (u8 *)&block,

			crypto_cipher_encrypt_one(cipher, (u8 *)&block,

						  (u8 *)&block);

			/* perform KW operation: modify IV with counter */

			block.A ^= cpu_to_be64(t);
@@ -254,117 +244,59 @@ static int crypto_kw_encrypt(struct blkcipher_desc *desc, 
			scatterwalk_copychunks(&block.R, &dst_walk, SEMIBSIZE,

					       true);



			tmp_nbytes -= SEMIBSIZE;

			nbytes -= SEMIBSIZE;

		}



		/* we now start to operate on the dst SGL only */

		lsrc = dst;

		ldst = dst;

		src = req->dst;

		dst = req->dst;

	}



	/* establish the IV for the caller to pick up */

	memcpy(desc->info, &block.A, SEMIBSIZE);

	memcpy(req->iv, &block.A, SEMIBSIZE);



	memzero_explicit(&block, sizeof(struct crypto_kw_block));



	return 0;

}



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

			    unsigned int keylen)

{

	struct crypto_kw_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_kw_init_tfm(struct crypto_tfm *tfm)

{

	struct crypto_instance *inst = crypto_tfm_alg_instance(tfm);

	struct crypto_spawn *spawn = crypto_instance_ctx(inst);

	struct crypto_kw_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_kw_exit_tfm(struct crypto_tfm *tfm)

static int crypto_kw_create(struct crypto_template *tmpl, struct rtattr **tb)

{

	struct crypto_kw_ctx *ctx = crypto_tfm_ctx(tfm);



	crypto_free_cipher(ctx->child);

}



static struct crypto_instance *crypto_kw_alloc(struct rtattr **tb)

{

	struct crypto_instance *inst = NULL;

	struct crypto_alg *alg = NULL;

	struct skcipher_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_get_attr_alg(tb, CRYPTO_ALG_TYPE_CIPHER,

				  CRYPTO_ALG_TYPE_MASK);

	if (IS_ERR(alg))

		return ERR_CAST(alg);

	inst = skcipher_alloc_instance_simple(tmpl, tb, &alg);

	if (IS_ERR(inst))

		return PTR_ERR(inst);



	inst = ERR_PTR(-EINVAL);

	err = -EINVAL;

	/* Section 5.1 requirement for KW */

	if (alg->cra_blocksize != sizeof(struct crypto_kw_block))

		goto err;

		goto out_free_inst;



	inst = crypto_alloc_instance("kw", alg);

	if (IS_ERR(inst))

		goto err;

	inst->alg.base.cra_blocksize = SEMIBSIZE;

	inst->alg.base.cra_alignmask = 0;

	inst->alg.ivsize = SEMIBSIZE;



	inst->alg.cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER;

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

	inst->alg.cra_blocksize = SEMIBSIZE;

	inst->alg.cra_alignmask = 0;

	inst->alg.cra_type = &crypto_blkcipher_type;

	inst->alg.cra_blkcipher.ivsize = SEMIBSIZE;

	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.encrypt = crypto_kw_encrypt;

	inst->alg.decrypt = crypto_kw_decrypt;



	inst->alg.cra_ctxsize = sizeof(struct crypto_kw_ctx);



	inst->alg.cra_init = crypto_kw_init_tfm;

	inst->alg.cra_exit = crypto_kw_exit_tfm;



	inst->alg.cra_blkcipher.setkey = crypto_kw_setkey;

	inst->alg.cra_blkcipher.encrypt = crypto_kw_encrypt;

	inst->alg.cra_blkcipher.decrypt = crypto_kw_decrypt;

	err = skcipher_register_instance(tmpl, inst);

	if (err)

		goto out_free_inst;

	goto out_put_alg;



err:

out_free_inst:

	inst->free(inst);

out_put_alg:

	crypto_mod_put(alg);

	return inst;

}



static void crypto_kw_free(struct crypto_instance *inst)

{

	crypto_drop_spawn(crypto_instance_ctx(inst));

	kfree(inst);

	return err;

}



static struct crypto_template crypto_kw_tmpl = {

	.name = "kw",

	.alloc = crypto_kw_alloc,

	.free = crypto_kw_free,

	.create = crypto_kw_create,

	.module = THIS_MODULE,

};

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