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Commit 531fa5d6 authored by Kees Cook's avatar Kees Cook Committed by Herbert Xu
Browse files

s390/crypto: Remove VLA usage of skcipher 

In the quest to remove all stack VLA usage from the kernel[1], this
replaces struct crypto_skcipher and SKCIPHER_REQUEST_ON_STACK() usage
with struct crypto_sync_skcipher and SYNC_SKCIPHER_REQUEST_ON_STACK(),
which uses a fixed stack size.

[1] https://lkml.kernel.org/r/CA+55aFzCG-zNmZwX4A2FQpadafLfEzK6CC=qPXydAacU1RqZWA@mail.gmail.com



Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: linux-s390@vger.kernel.org
Signed-off-by: default avatarKees Cook <keescook@chromium.org>
Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
parent 3103f4a7

arch/s390/crypto/aes_s390.c

+24 −24
Original line number Diff line number Diff line
@@ -44,7 +44,7 @@ struct s390_aes_ctx { 
	int key_len;

	unsigned long fc;

	union {

		struct crypto_skcipher *blk;

		struct crypto_sync_skcipher *blk;

		struct crypto_cipher *cip;

	} fallback;

};
@@ -54,7 +54,7 @@ struct s390_xts_ctx { 
	u8 pcc_key[32];

	int key_len;

	unsigned long fc;

	struct crypto_skcipher *fallback;

	struct crypto_sync_skcipher *fallback;

};



struct gcm_sg_walk {
@@ -184,14 +184,15 @@ static int setkey_fallback_blk(struct crypto_tfm *tfm, const u8 *key, 
	struct s390_aes_ctx *sctx = crypto_tfm_ctx(tfm);

	unsigned int ret;



	crypto_skcipher_clear_flags(sctx->fallback.blk, CRYPTO_TFM_REQ_MASK);

	crypto_skcipher_set_flags(sctx->fallback.blk, tfm->crt_flags &

	crypto_sync_skcipher_clear_flags(sctx->fallback.blk,

					 CRYPTO_TFM_REQ_MASK);

	crypto_sync_skcipher_set_flags(sctx->fallback.blk, tfm->crt_flags &

						      CRYPTO_TFM_REQ_MASK);



	ret = crypto_skcipher_setkey(sctx->fallback.blk, key, len);

	ret = crypto_sync_skcipher_setkey(sctx->fallback.blk, key, len);



	tfm->crt_flags &= ~CRYPTO_TFM_RES_MASK;

	tfm->crt_flags |= crypto_skcipher_get_flags(sctx->fallback.blk) &

	tfm->crt_flags |= crypto_sync_skcipher_get_flags(sctx->fallback.blk) &

			  CRYPTO_TFM_RES_MASK;



	return ret;
@@ -204,9 +205,9 @@ static int fallback_blk_dec(struct blkcipher_desc *desc, 
	unsigned int ret;

	struct crypto_blkcipher *tfm = desc->tfm;

	struct s390_aes_ctx *sctx = crypto_blkcipher_ctx(tfm);

	SKCIPHER_REQUEST_ON_STACK(req, sctx->fallback.blk);

	SYNC_SKCIPHER_REQUEST_ON_STACK(req, sctx->fallback.blk);



	skcipher_request_set_tfm(req, sctx->fallback.blk);

	skcipher_request_set_sync_tfm(req, sctx->fallback.blk);

	skcipher_request_set_callback(req, desc->flags, NULL, NULL);

	skcipher_request_set_crypt(req, src, dst, nbytes, desc->info);
@@ -223,9 +224,9 @@ static int fallback_blk_enc(struct blkcipher_desc *desc, 
	unsigned int ret;

	struct crypto_blkcipher *tfm = desc->tfm;

	struct s390_aes_ctx *sctx = crypto_blkcipher_ctx(tfm);

	SKCIPHER_REQUEST_ON_STACK(req, sctx->fallback.blk);

	SYNC_SKCIPHER_REQUEST_ON_STACK(req, sctx->fallback.blk);



	skcipher_request_set_tfm(req, sctx->fallback.blk);

	skcipher_request_set_sync_tfm(req, sctx->fallback.blk);

	skcipher_request_set_callback(req, desc->flags, NULL, NULL);

	skcipher_request_set_crypt(req, src, dst, nbytes, desc->info);
@@ -306,8 +307,7 @@ static int fallback_init_blk(struct crypto_tfm *tfm) 
	const char *name = tfm->__crt_alg->cra_name;

	struct s390_aes_ctx *sctx = crypto_tfm_ctx(tfm);



	sctx->fallback.blk = crypto_alloc_skcipher(name, 0,

						   CRYPTO_ALG_ASYNC |

	sctx->fallback.blk = crypto_alloc_sync_skcipher(name, 0,

						   CRYPTO_ALG_NEED_FALLBACK);



	if (IS_ERR(sctx->fallback.blk)) {
@@ -323,7 +323,7 @@ static void fallback_exit_blk(struct crypto_tfm *tfm) 
{

	struct s390_aes_ctx *sctx = crypto_tfm_ctx(tfm);



	crypto_free_skcipher(sctx->fallback.blk);

	crypto_free_sync_skcipher(sctx->fallback.blk);

}



static struct crypto_alg ecb_aes_alg = {
@@ -453,14 +453,15 @@ static int xts_fallback_setkey(struct crypto_tfm *tfm, const u8 *key, 
	struct s390_xts_ctx *xts_ctx = crypto_tfm_ctx(tfm);

	unsigned int ret;



	crypto_skcipher_clear_flags(xts_ctx->fallback, CRYPTO_TFM_REQ_MASK);

	crypto_skcipher_set_flags(xts_ctx->fallback, tfm->crt_flags &

	crypto_sync_skcipher_clear_flags(xts_ctx->fallback,

					 CRYPTO_TFM_REQ_MASK);

	crypto_sync_skcipher_set_flags(xts_ctx->fallback, tfm->crt_flags &

						     CRYPTO_TFM_REQ_MASK);



	ret = crypto_skcipher_setkey(xts_ctx->fallback, key, len);

	ret = crypto_sync_skcipher_setkey(xts_ctx->fallback, key, len);



	tfm->crt_flags &= ~CRYPTO_TFM_RES_MASK;

	tfm->crt_flags |= crypto_skcipher_get_flags(xts_ctx->fallback) &

	tfm->crt_flags |= crypto_sync_skcipher_get_flags(xts_ctx->fallback) &

			  CRYPTO_TFM_RES_MASK;



	return ret;
@@ -472,10 +473,10 @@ static int xts_fallback_decrypt(struct blkcipher_desc *desc, 
{

	struct crypto_blkcipher *tfm = desc->tfm;

	struct s390_xts_ctx *xts_ctx = crypto_blkcipher_ctx(tfm);

	SKCIPHER_REQUEST_ON_STACK(req, xts_ctx->fallback);

	SYNC_SKCIPHER_REQUEST_ON_STACK(req, xts_ctx->fallback);

	unsigned int ret;



	skcipher_request_set_tfm(req, xts_ctx->fallback);

	skcipher_request_set_sync_tfm(req, xts_ctx->fallback);

	skcipher_request_set_callback(req, desc->flags, NULL, NULL);

	skcipher_request_set_crypt(req, src, dst, nbytes, desc->info);
@@ -491,10 +492,10 @@ static int xts_fallback_encrypt(struct blkcipher_desc *desc, 
{

	struct crypto_blkcipher *tfm = desc->tfm;

	struct s390_xts_ctx *xts_ctx = crypto_blkcipher_ctx(tfm);

	SKCIPHER_REQUEST_ON_STACK(req, xts_ctx->fallback);

	SYNC_SKCIPHER_REQUEST_ON_STACK(req, xts_ctx->fallback);

	unsigned int ret;



	skcipher_request_set_tfm(req, xts_ctx->fallback);

	skcipher_request_set_sync_tfm(req, xts_ctx->fallback);

	skcipher_request_set_callback(req, desc->flags, NULL, NULL);

	skcipher_request_set_crypt(req, src, dst, nbytes, desc->info);
@@ -611,8 +612,7 @@ static int xts_fallback_init(struct crypto_tfm *tfm) 
	const char *name = tfm->__crt_alg->cra_name;

	struct s390_xts_ctx *xts_ctx = crypto_tfm_ctx(tfm);



	xts_ctx->fallback = crypto_alloc_skcipher(name, 0,

						  CRYPTO_ALG_ASYNC |

	xts_ctx->fallback = crypto_alloc_sync_skcipher(name, 0,

						  CRYPTO_ALG_NEED_FALLBACK);



	if (IS_ERR(xts_ctx->fallback)) {
@@ -627,7 +627,7 @@ static void xts_fallback_exit(struct crypto_tfm *tfm) 
{

	struct s390_xts_ctx *xts_ctx = crypto_tfm_ctx(tfm);



	crypto_free_skcipher(xts_ctx->fallback);

	crypto_free_sync_skcipher(xts_ctx->fallback);

}



static struct crypto_alg xts_aes_alg = {