static void *mcryptd_alloc_instance(struct crypto_alg *alg, unsigned int head,
				   unsigned int tail)
{
	char *p;
	struct crypto_instance *inst;
	int err;

	p = kzalloc(head + sizeof(*inst) + tail, GFP_KERNEL);
	if (!p)
		return ERR_PTR(-ENOMEM);

	inst = (void *)(p + head);

	err = -ENAMETOOLONG;
	if (snprintf(inst->alg.cra_driver_name, CRYPTO_MAX_ALG_NAME,
		    "mcryptd(%s)", alg->cra_driver_name) >= CRYPTO_MAX_ALG_NAME)
		goto out_free_inst;

	memcpy(inst->alg.cra_name, alg->cra_name, CRYPTO_MAX_ALG_NAME);

	inst->alg.cra_priority = alg->cra_priority + 50;
	inst->alg.cra_blocksize = alg->cra_blocksize;
	inst->alg.cra_alignmask = alg->cra_alignmask;

out:
	return p;

out_free_inst:
	kfree(p);
	p = ERR_PTR(err);
	goto out;
}

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