path: root/crypto/algapi.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Cryptographic API for algorithms (i.e., low-level API).
 *
 * Copyright (c) 2006 Herbert Xu <herbert@gondor.apana.org.au>
 */

#include <crypto/algapi.h>
#include <crypto/internal/simd.h>
#include <linux/err.h>
#include <linux/errno.h>
#include <linux/fips.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/module.h>
#include <linux/rtnetlink.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/workqueue.h>

#include "internal.h"

static LIST_HEAD(crypto_template_list);

#ifdef CONFIG_CRYPTO_MANAGER_EXTRA_TESTS
DEFINE_PER_CPU(bool, crypto_simd_disabled_for_test);
EXPORT_PER_CPU_SYMBOL_GPL(crypto_simd_disabled_for_test);
#endif

static inline void crypto_check_module_sig(struct module *mod)
{
	if (fips_enabled && mod && !module_sig_ok(mod))
		panic("Module %s signature verification failed in FIPS mode\n",
		      module_name(mod));
}

static int crypto_check_alg(struct crypto_alg *alg)
{
	crypto_check_module_sig(alg->cra_module);

	if (!alg->cra_name[0] || !alg->cra_driver_name[0])
		return -EINVAL;

	if (alg->cra_alignmask & (alg->cra_alignmask + 1))
		return -EINVAL;

	/* General maximums for all algs. */
	if (alg->cra_alignmask > MAX_ALGAPI_ALIGNMASK)
		return -EINVAL;

	if (alg->cra_blocksize > MAX_ALGAPI_BLOCKSIZE)
		return -EINVAL;

	/* Lower maximums for specific alg types. */
	if (!alg->cra_type && (alg->cra_flags & CRYPTO_ALG_TYPE_MASK) ==
			       CRYPTO_ALG_TYPE_CIPHER) {
		if (alg->cra_alignmask > MAX_CIPHER_ALIGNMASK)
			return -EINVAL;

		if (alg->cra_blocksize > MAX_CIPHER_BLOCKSIZE)
			return -EINVAL;
	}

	if (alg->cra_priority < 0)
		return -EINVAL;

	refcount_set(&alg->cra_refcnt, 1);

	return 0;
}

static void crypto_free_instance(struct crypto_instance *inst)
{
	inst->alg.cra_type->free(inst);
}

static void crypto_destroy_instance_workfn(struct work_struct *w)
{
	struct crypto_instance *inst = container_of(w, struct crypto_instance,
						    free_work);
	struct crypto_template *tmpl = inst->tmpl;

	crypto_free_instance(inst);
	crypto_tmpl_put(tmpl);
}

static void crypto_destroy_instance(struct crypto_alg *alg)
{
	struct crypto_instance *inst = container_of(alg,
						    struct crypto_instance,
						    alg);

	INIT_WORK(&inst->free_work, crypto_destroy_instance_workfn);
	schedule_work(&inst->free_work);
}

/*
 * This function adds a spawn to the list secondary_spawns which
 * will be used at the end of crypto_remove_spawns to unregister
 * instances, unless the spawn happens to be one that is depended
 * on by the new algorithm (nalg in crypto_remove_spawns).
 *
 * This function is also responsible for resurrecting any algorithms
 * in the dependency chain of nalg by unsetting n->dead.
 */
static struct list_head *crypto_more_spawns(struct crypto_alg *alg,
					    struct list_head *stack,
					    struct list_head *top,
					    struct list_head *secondary_spawns)
{
	struct crypto_spawn *spawn, *n;

	spawn = list_first_entry_or_null(stack, struct crypto_spawn, list);
	if (!spawn)
		return NULL;

	n = list_prev_entry(spawn, list);
	list_move(&spawn->list, secondary_spawns);

	if (list_is_last(&n->list, stack))
		return top;

	n = list_next_entry(n, list);
	if (!spawn->dead)
		n->dead = false;

	return &n->inst->alg.cra_users;
}

static void crypto_remove_instance(struct crypto_instance *inst,
				   struct list_head *list)
{
	struct crypto_template *tmpl = inst->tmpl;

	if (crypto_is_dead(&inst->alg))
		return;

	inst->alg.cra_flags |= CRYPTO_ALG_DEAD;

	if (!tmpl || !crypto_tmpl_get(tmpl))
		return;

	list_move(&inst->alg.cra_list, list);
	hlist_del(&inst->list);
	inst->alg.cra_destroy = crypto_destroy_instance;

	BUG_ON(!list_empty(&inst->alg.cra_users));
}

/*
 * Given an algorithm alg, remove all algorithms that depend on it
 * through spawns.  If nalg is not null, then exempt any algorithms
 * that is depended on by nalg.  This is useful when nalg itself
 * depends on alg.
 */
void crypto_remove_spawns(struct crypto_alg *alg, struct list_head *list,
			  struct crypto_alg *nalg)
{
	u32 new_type = (nalg ?: alg)->cra_flags;
	struct crypto_spawn *spawn, *