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Commit 88fe0b95 authored by Kees Cook's avatar Kees Cook Committed by Herbert Xu
Browse files

x86/fpu: 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: x86@kernel.org
Signed-off-by: default avatarKees Cook <keescook@chromium.org>
Reviewed-by: default avatarArd Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
parent 531fa5d6

arch/x86/crypto/fpu.c

+16 −14
Original line number Diff line number Diff line
@@ -20,21 +20,23 @@ 
#include <asm/fpu/api.h>



struct crypto_fpu_ctx {

	struct crypto_skcipher *child;

	struct crypto_sync_skcipher *child;

};



static int crypto_fpu_setkey(struct crypto_skcipher *parent, const u8 *key,

			     unsigned int keylen)

{

	struct crypto_fpu_ctx *ctx = crypto_skcipher_ctx(parent);

	struct crypto_skcipher *child = ctx->child;

	struct crypto_sync_skcipher *child = ctx->child;

	int err;



	crypto_skcipher_clear_flags(child, CRYPTO_TFM_REQ_MASK);

	crypto_skcipher_set_flags(child, crypto_skcipher_get_flags(parent) &

	crypto_sync_skcipher_clear_flags(child, CRYPTO_TFM_REQ_MASK);

	crypto_sync_skcipher_set_flags(child,

				       crypto_skcipher_get_flags(parent) &

					 CRYPTO_TFM_REQ_MASK);

	err = crypto_skcipher_setkey(child, key, keylen);

	crypto_skcipher_set_flags(parent, crypto_skcipher_get_flags(child) &

	err = crypto_sync_skcipher_setkey(child, key, keylen);

	crypto_skcipher_set_flags(parent,

				  crypto_sync_skcipher_get_flags(child) &

					  CRYPTO_TFM_RES_MASK);

	return err;

}
@@ -43,11 +45,11 @@ static int crypto_fpu_encrypt(struct skcipher_request *req) 
{

	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);

	struct crypto_fpu_ctx *ctx = crypto_skcipher_ctx(tfm);

	struct crypto_skcipher *child = ctx->child;

	SKCIPHER_REQUEST_ON_STACK(subreq, child);

	struct crypto_sync_skcipher *child = ctx->child;

	SYNC_SKCIPHER_REQUEST_ON_STACK(subreq, child);

	int err;



	skcipher_request_set_tfm(subreq, child);

	skcipher_request_set_sync_tfm(subreq, child);

	skcipher_request_set_callback(subreq, 0, NULL, NULL);

	skcipher_request_set_crypt(subreq, req->src, req->dst, req->cryptlen,

				   req->iv);
@@ -64,11 +66,11 @@ static int crypto_fpu_decrypt(struct skcipher_request *req) 
{

	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);

	struct crypto_fpu_ctx *ctx = crypto_skcipher_ctx(tfm);

	struct crypto_skcipher *child = ctx->child;

	SKCIPHER_REQUEST_ON_STACK(subreq, child);

	struct crypto_sync_skcipher *child = ctx->child;

	SYNC_SKCIPHER_REQUEST_ON_STACK(subreq, child);

	int err;



	skcipher_request_set_tfm(subreq, child);

	skcipher_request_set_sync_tfm(subreq, child);

	skcipher_request_set_callback(subreq, 0, NULL, NULL);

	skcipher_request_set_crypt(subreq, req->src, req->dst, req->cryptlen,

				   req->iv);
@@ -93,7 +95,7 @@ static int crypto_fpu_init_tfm(struct crypto_skcipher *tfm) 
	if (IS_ERR(cipher))

		return PTR_ERR(cipher);



	ctx->child = cipher;

	ctx->child = (struct crypto_sync_skcipher *)cipher;



	return 0;

}
@@ -102,7 +104,7 @@ static void crypto_fpu_exit_tfm(struct crypto_skcipher *tfm) 
{

	struct crypto_fpu_ctx *ctx = crypto_skcipher_ctx(tfm);



	crypto_free_skcipher(ctx->child);

	crypto_free_sync_skcipher(ctx->child);

}



static void crypto_fpu_free(struct skcipher_instance *inst)