static int xcbc_create(struct crypto_template *tmpl, struct rtattr **tb)
{
	struct shash_instance *inst;
	struct crypto_alg *alg;
	unsigned long alignmask;
	int err;

	err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_SHASH);
	if (err)
		return err;

	alg = crypto_get_attr_alg(tb, CRYPTO_ALG_TYPE_CIPHER,
				  CRYPTO_ALG_TYPE_MASK);
	if (IS_ERR(alg))
		return PTR_ERR(alg);

	switch(alg->cra_blocksize) {
	case 16:
		break;
	default:
		goto out_put_alg;
	}

	inst = shash_alloc_instance("xcbc", alg);
	err = PTR_ERR(inst);
	if (IS_ERR(inst))
		goto out_put_alg;

	err = crypto_init_spawn(shash_instance_ctx(inst), alg,
				shash_crypto_instance(inst),
				CRYPTO_ALG_TYPE_MASK);
	if (err)
		goto out_free_inst;

	alignmask = alg->cra_alignmask | 3;
	inst->alg.base.cra_alignmask = alignmask;
	inst->alg.base.cra_priority = alg->cra_priority;
	inst->alg.base.cra_blocksize = alg->cra_blocksize;

	inst->alg.digestsize = alg->cra_blocksize;
	inst->alg.descsize = ALIGN(sizeof(struct xcbc_desc_ctx),
				   crypto_tfm_ctx_alignment()) +
			     (alignmask &
			      ~(crypto_tfm_ctx_alignment() - 1)) +
			     alg->cra_blocksize * 2;

	inst->alg.base.cra_ctxsize = ALIGN(sizeof(struct xcbc_tfm_ctx),
					   alignmask + 1) +
				     alg->cra_blocksize * 2;
	inst->alg.base.cra_init = xcbc_init_tfm;
	inst->alg.base.cra_exit = xcbc_exit_tfm;

	inst->alg.init = crypto_xcbc_digest_init;
	inst->alg.update = crypto_xcbc_digest_update;
	inst->alg.final = crypto_xcbc_digest_final;
	inst->alg.setkey = crypto_xcbc_digest_setkey;

	err = shash_register_instance(tmpl, inst);
	if (err) {
out_free_inst:
		shash_free_instance(shash_crypto_instance(inst));
	}

out_put_alg:
	crypto_mod_put(alg);
	return err;
}

This category addresses vulnerabilities caused by flawed access control mechanisms, where incorrect permission settings allow unauthorized users to access restricted resources.