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// 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 <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 "internal.h" static LIST_HEAD(crypto_template_list); 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(struct crypto_alg *alg){	struct crypto_instance *inst = (void *)alg;	struct crypto_template *tmpl = inst->tmpl; 	crypto_free_instance(inst);	crypto_tmpl_put(tmpl);} /* * 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, *n;	LIST_HEAD(secondary_spawns);	struct list_head *spawns;	LIST_HEAD(stack);	LIST_HEAD(top); 	spawns = &alg->cra_users;	list_for_each_entry_safe(spawn, n, spawns, list) {		if ((spawn->alg->cra_flags ^ new_type) & spawn->mask)			continue; 		list_move(&spawn->list, &top);	} 	/*	 * Perform a depth-first walk starting from alg through	 * the cra_users tree.  The list stack records the path	 * from alg to the current spawn.	 */	spawns = &top;	do {		while (!list_empty(spawns)) {			struct crypto_instance *inst; 			spawn = list_first_entry(spawns, struct crypto_spawn,						 list);			inst = spawn->inst; 			list_move(&spawn->list, &stack);			spawn->dead = !spawn->registered || &inst->alg != nalg; 			if (!spawn->registered)				break; 			BUG_ON(&inst->alg == alg); 			if (&inst->alg == nalg)				break; 			spawns = &inst->alg.cra_users; 			/*			 * Even if spawn->registered is true, the			 * instance itself may still be unregistered.			 * This is because it may have failed during			 * registration.  Therefore we still need to			 * make the following test.			 *			 * We may encounter an unregistered instance here, since			 * an instance's spawns are set up prior to the instance			 * being registered.  An unregistered instance will have			 * NULL ->cra_users.next, since ->cra_users isn't			 * properly initialized until registration.  But an			 * unregistered instance cannot have any users, so treat			 * it the same as ->cra_users being empty.			 */			if (spawns->next == NULL)				break;		}	} while ((spawns = crypto_more_spawns(alg, &stack, &top,					      &secondary_spawns))); 	/*	 * Remove all instances that are marked as dead.  Also	 * complete the resurrection of the others by moving them	 * back to the cra_users list.	 */	list_for_each_entry_safe(spawn, n, &secondary_spawns, list) {		if (!spawn->dead)			list_move(&spawn->list, &spawn->alg->cra_users);		else if (spawn->registered)			crypto_remove_instance(spawn->inst, list);	}}EXPORT_SYMBOL_GPL(crypto_remove_spawns); static struct crypto_larval *__crypto_register_alg(struct crypto_alg *alg){	struct crypto_alg *q;	struct crypto_larval *larval;	int ret = -EAGAIN; 	if (crypto_is_dead(alg))		goto err; 	INIT_LIST_HEAD(&alg->cra_users); 	/* No cheating! */	alg->cra_flags &= ~CRYPTO_ALG_TESTED; 	ret = -EEXIST; 	list_for_each_entry(q, &crypto_alg_list, cra_list) {		if (q == alg)			goto err; 		if (crypto_is_moribund(q))			continue; 		if (crypto_is_larval(q)) {			if (!strcmp(alg->cra_driver_name, q->cra_driver_name))				goto err;			continue;		} 		if (!strcmp(q->cra_driver_name, alg->cra_name) ||		    !strcmp(q->cra_name, alg->cra_driver_name))			goto err;	} 	larval = crypto_larval_alloc(alg->cra_name,				     alg->cra_flags | CRYPTO_ALG_TESTED, 0);	if (IS_ERR(larval))		goto out; 	ret = -ENOENT;	larval->adult = crypto_mod_get(alg);	if (!larval->adult)		goto free_larval; 	refcount_set(&larval->alg.cra_refcnt, 1);	memcpy(larval->alg.cra_driver_name, alg->cra_driver_name,	       CRYPTO_MAX_ALG_NAME);	larval->alg.cra_priority = alg->cra_priority; 	list_add(&alg->cra_list, &crypto_alg_list);	list_add(&larval->alg.cra_list, &crypto_alg_list); 	crypto_stats_init(alg); out:	return larval; free_larval:	kfree(larval);err:	larval = ERR_PTR(ret);	goto out;} void crypto_alg_tested(const char *name, int err){	struct crypto_larval *test;	struct crypto_alg *alg;	struct crypto_alg *q;	LIST_HEAD(list);	bool best; 	down_write(&crypto_alg_sem);	list_for_each_entry(q, &crypto_alg_list, cra_list) {		if (crypto_is_moribund(q) || !crypto_is_larval(q))			continue; 		test = (struct crypto_larval *)q; 		if (!strcmp(q->cra_driver_name, name))			goto found;	} 	pr_err("alg: Unexpected test result for %s: %d\n", name, err);	goto unlock; found:	q->cra_flags |= CRYPTO_ALG_DEAD;	alg = test->adult;	if (err || list_empty(&alg->cra_list))		goto complete; 	alg->cra_flags |= CRYPTO_ALG_TESTED; 	/* Only satisfy larval waiters if we are the best. */	best = true;	list_for_each_entry(q, &crypto_alg_list, cra_list) {		if (crypto_is_moribund(q) || !crypto_is_larval(q))			continue; 		if (strcmp(alg->cra_name, q->cra_name))			continue; 		if (q->cra_priority > alg->cra_priority) {			best = false;			break;		}	} 	list_for_each_entry(q, &crypto_alg_list, cra_list) {		if (q == alg)			continue; 		if (crypto_is_moribund(q))			continue; 		if (crypto_is_larval(q)) {			struct crypto_larval *larval = (void *)q; 			/*			 * Check to see if either our generic name or			 * specific name can satisfy the name requested			 * by the larval entry q.			 */			if (strcmp(alg->cra_name, q->cra_name) &&			    strcmp(alg->cra_driver_name, q->cra_name))				continue; 			if (larval->adult)				continue;			if ((q->cra_flags ^ alg->cra_flags) & larval->mask)				continue; 			if (best && crypto_mod_get(alg))				larval->adult = alg;			else				larval->adult = ERR_PTR(-EAGAIN); 			continue;		} 		if (strcmp(alg->cra_name, q->cra_name))			continue; 		if (strcmp(alg->cra_driver_name, q->cra_driver_name) &&		    q->cra_priority > alg->cra_priority)			continue; 		crypto_remove_spawns(q, &list, alg);	} complete:	complete_all(&test->completion); unlock:	up_write(&crypto_alg_sem); 	crypto_remove_final(&list);}EXPORT_SYMBOL_GPL(crypto_alg_tested); void crypto_remove_final(struct list_head *list){	struct crypto_alg *alg;	struct crypto_alg *n; 	list_for_each_entry_safe(alg, n, list, cra_list) {		list_del_init(&alg->cra_list);		crypto_alg_put(alg);	}}EXPORT_SYMBOL_GPL(crypto_remove_final); static void crypto_wait_for_test(struct crypto_larval *larval){	int err; 	err = crypto_probing_notify(CRYPTO_MSG_ALG_REGISTER, larval->adult);	if (err != NOTIFY_STOP) {		if (WARN_ON(err != NOTIFY_DONE))			goto out;		crypto_alg_tested(larval->alg.cra_driver_name, 0);	} 	err = wait_for_completion_killable(&larval->completion);	WARN_ON(err);	if (!err)		crypto_probing_notify(CRYPTO_MSG_ALG_LOADED, larval); out:	crypto_larval_kill(&larval->alg);} int crypto_register_alg(struct crypto_alg *alg){	struct crypto_larval *larval;	int err; 	alg->cra_flags &= ~CRYPTO_ALG_DEAD;	err = crypto_check_alg(alg);	if (err)		return err; 	down_write(&crypto_alg_sem);	larval = __crypto_register_alg(alg);	up_write(&crypto_alg_sem); 	if (IS_ERR(larval))		return PTR_ERR(larval); 	crypto_wait_for_test(larval);	return 0;}EXPORT_SYMBOL_GPL(crypto_register_alg); static int crypto_remove_alg(struct crypto_alg *alg, struct list_head *list){	if (unlikely(list_empty(&alg->cra_list)))		return -ENOENT; 	alg->cra_flags |= CRYPTO_ALG_DEAD; 	list_del_init(&alg->cra_list);	crypto_remove_spawns(alg, list, NULL); 	return 0;} void crypto_unregister_alg(struct crypto_alg *alg){	int ret;	LIST_HEAD(list); 	down_write(&crypto_alg_sem);	ret = crypto_remove_alg(alg, &list);	up_write(&crypto_alg_sem); 	if (WARN(ret, "Algorithm %s is not registered", alg->cra_driver_name))		return; 	BUG_ON(refcount_read(&alg->cra_refcnt) != 1);	if (alg->cra_destroy)		alg->cra_destroy(alg); 	crypto_remove_final(&list);}EXPORT_SYMBOL_GPL(crypto_unregister_alg); int crypto_register_algs(struct crypto_alg *algs, int count){	int i, ret; 	for (i = 0; i < count; i++) {		ret = crypto_register_alg(&algs[i]);		if (ret)			goto err;	} 	return 0; err:	for (--i; i >= 0; --i)		crypto_unregister_alg(&algs[i]); 	return ret;}EXPORT_SYMBOL_GPL(crypto_register_algs); void crypto_unregister_algs(struct crypto_alg *algs, int count){	int i; 	for (i = 0; i < count; i++)		crypto_unregister_alg(&algs[i]);}EXPORT_SYMBOL_GPL(crypto_unregister_algs); int crypto_register_template(struct crypto_template *tmpl){	struct crypto_template *q;	int err = -EEXIST; 

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