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Commit 6d56799a authored by Kees Cook's avatar Kees Cook Committed by Rishabh Bhatnagar
Browse files

crypto: xcbc - Remove VLA usage 

In the quest to remove all stack VLA usage from the kernel[1], this uses
the maximum blocksize and adds a sanity check. For xcbc, the blocksize
must always be 16, so use that, since it's already being enforced during
instantiation.

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



Change-Id: I4b1f851ccd31004cc5c0c28e73385aa16bcb53a9
Signed-off-by: default avatarKees Cook <keescook@chromium.org>
Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
Git-Repo: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git


Git-Commit: 3bdd23f886c08a0d649c535e1e2cf083ec600036
Signed-off-by: default avatarRishabh Bhatnagar <rishabhb@codeaurora.org>
parent 69aafa11

crypto/xcbc.c

+5 −3
Original line number Diff line number Diff line
@@ -57,15 +57,17 @@ struct xcbc_desc_ctx { 
	u8 ctx[];

};



#define XCBC_BLOCKSIZE	16



static int crypto_xcbc_digest_setkey(struct crypto_shash *parent,

				     const u8 *inkey, unsigned int keylen)

{

	unsigned long alignmask = crypto_shash_alignmask(parent);

	struct xcbc_tfm_ctx *ctx = crypto_shash_ctx(parent);

	int bs = crypto_shash_blocksize(parent);

	u8 *consts = PTR_ALIGN(&ctx->ctx[0], alignmask + 1);

	int err = 0;

	u8 key1[bs];

	u8 key1[XCBC_BLOCKSIZE];

	int bs = sizeof(key1);



	if ((err = crypto_cipher_setkey(ctx->child, inkey, keylen)))

		return err;
@@ -212,7 +214,7 @@ static int xcbc_create(struct crypto_template *tmpl, struct rtattr **tb) 
		return PTR_ERR(alg);



	switch(alg->cra_blocksize) {

	case 16:

	case XCBC_BLOCKSIZE:

		break;

	default:

		goto out_put_alg;