Commit 4e39d071 authored by Eric Biggers's avatar Eric Biggers Committed by Herbert Xu
Browse files

crypto: gcm - use memcpy_sglist() instead of null skcipher 



For copying data between two scatterlists, just use memcpy_sglist()
instead of the so-called "null skcipher".  This is much simpler.

Signed-off-by: default avatarEric Biggers <ebiggers@google.com>
Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
parent dbc4b145

crypto/Kconfig

+0 −1
Original line number Diff line number Diff line
@@ -805,7 +805,6 @@ config CRYPTO_GCM 
	select CRYPTO_CTR

	select CRYPTO_AEAD

	select CRYPTO_GHASH

	select CRYPTO_NULL

	select CRYPTO_MANAGER

	help

	  GCM (Galois/Counter Mode) authenticated encryption mode and GMAC

crypto/gcm.c

+4 −37
Original line number Diff line number Diff line
@@ -9,7 +9,6 @@ 
#include <crypto/internal/aead.h>

#include <crypto/internal/skcipher.h>

#include <crypto/internal/hash.h>

#include <crypto/null.h>

#include <crypto/scatterwalk.h>

#include <crypto/gcm.h>

#include <crypto/hash.h>
@@ -46,7 +45,6 @@ struct crypto_rfc4543_instance_ctx { 


struct crypto_rfc4543_ctx {

	struct crypto_aead *child;

	struct crypto_sync_skcipher *null;

	u8 nonce[4];

};
@@ -79,8 +77,6 @@ static struct { 
	struct scatterlist sg;

} *gcm_zeroes;



static int crypto_rfc4543_copy_src_to_dst(struct aead_request *req, bool enc);



static inline struct crypto_gcm_req_priv_ctx *crypto_gcm_reqctx(

	struct aead_request *req)

{
@@ -930,12 +926,12 @@ static int crypto_rfc4543_crypt(struct aead_request *req, bool enc) 
	unsigned int authsize = crypto_aead_authsize(aead);

	u8 *iv = PTR_ALIGN((u8 *)(rctx + 1) + crypto_aead_reqsize(ctx->child),

			   crypto_aead_alignmask(ctx->child) + 1);

	int err;



	if (req->src != req->dst) {

		err = crypto_rfc4543_copy_src_to_dst(req, enc);

		if (err)

			return err;

		unsigned int nbytes = req->assoclen + req->cryptlen -

				      (enc ? 0 : authsize);



		memcpy_sglist(req->dst, req->src, nbytes);

	}



	memcpy(iv, ctx->nonce, 4);
@@ -952,22 +948,6 @@ static int crypto_rfc4543_crypt(struct aead_request *req, bool enc) 
	return enc ? crypto_aead_encrypt(subreq) : crypto_aead_decrypt(subreq);

}



static int crypto_rfc4543_copy_src_to_dst(struct aead_request *req, bool enc)

{

	struct crypto_aead *aead = crypto_aead_reqtfm(req);

	struct crypto_rfc4543_ctx *ctx = crypto_aead_ctx(aead);

	unsigned int authsize = crypto_aead_authsize(aead);

	unsigned int nbytes = req->assoclen + req->cryptlen -

			      (enc ? 0 : authsize);

	SYNC_SKCIPHER_REQUEST_ON_STACK(nreq, ctx->null);



	skcipher_request_set_sync_tfm(nreq, ctx->null);

	skcipher_request_set_callback(nreq, req->base.flags, NULL, NULL);

	skcipher_request_set_crypt(nreq, req->src, req->dst, nbytes, NULL);



	return crypto_skcipher_encrypt(nreq);

}



static int crypto_rfc4543_encrypt(struct aead_request *req)

{

	return crypto_ipsec_check_assoclen(req->assoclen) ?:
@@ -987,21 +967,13 @@ static int crypto_rfc4543_init_tfm(struct crypto_aead *tfm) 
	struct crypto_aead_spawn *spawn = &ictx->aead;

	struct crypto_rfc4543_ctx *ctx = crypto_aead_ctx(tfm);

	struct crypto_aead *aead;

	struct crypto_sync_skcipher *null;

	unsigned long align;

	int err = 0;



	aead = crypto_spawn_aead(spawn);

	if (IS_ERR(aead))

		return PTR_ERR(aead);



	null = crypto_get_default_null_skcipher();

	err = PTR_ERR(null);

	if (IS_ERR(null))

		goto err_free_aead;



	ctx->child = aead;

	ctx->null = null;



	align = crypto_aead_alignmask(aead);

	align &= ~(crypto_tfm_ctx_alignment() - 1);
@@ -1012,10 +984,6 @@ static int crypto_rfc4543_init_tfm(struct crypto_aead *tfm) 
		align + GCM_AES_IV_SIZE);



	return 0;



err_free_aead:

	crypto_free_aead(aead);

	return err;

}



static void crypto_rfc4543_exit_tfm(struct crypto_aead *tfm)
@@ -1023,7 +991,6 @@ static void crypto_rfc4543_exit_tfm(struct crypto_aead *tfm) 
	struct crypto_rfc4543_ctx *ctx = crypto_aead_ctx(tfm);



	crypto_free_aead(ctx->child);

	crypto_put_default_null_skcipher();

}



static void crypto_rfc4543_free(struct aead_instance *inst)