kernel-ark/crypto/algapi.c
Herbert Xu a73e69965f [CRYPTO] api: Do not remove users unless new algorithm matches
As it is whenever a new algorithm with the same name is registered
users of the old algorithm will be removed so that they can take
advantage of the new algorithm.  This presents a problem when the
new algorithm is not equivalent to the old algorithm.  In particular,
the new algorithm might only function on top of the existing one.

Hence we should not remove users unless they can make use of the
new algorithm.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2007-05-02 14:38:32 +10:00

601 lines
13 KiB
C

/*
* Cryptographic API for algorithms (i.e., low-level API).
*
* Copyright (c) 2006 Herbert Xu <herbert@gondor.apana.org.au>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the Free
* Software Foundation; either version 2 of the License, or (at your option)
* any later version.
*
*/
#include <linux/err.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/module.h>
#include <linux/rtnetlink.h>
#include <linux/string.h>
#include "internal.h"
static LIST_HEAD(crypto_template_list);
void crypto_larval_error(const char *name, u32 type, u32 mask)
{
struct crypto_alg *alg;
down_read(&crypto_alg_sem);
alg = __crypto_alg_lookup(name, type, mask);
up_read(&crypto_alg_sem);
if (alg) {
if (crypto_is_larval(alg)) {
struct crypto_larval *larval = (void *)alg;
complete(&larval->completion);
}
crypto_mod_put(alg);
}
}
EXPORT_SYMBOL_GPL(crypto_larval_error);
static inline int crypto_set_driver_name(struct crypto_alg *alg)
{
static const char suffix[] = "-generic";
char *driver_name = alg->cra_driver_name;
int len;
if (*driver_name)
return 0;
len = strlcpy(driver_name, alg->cra_name, CRYPTO_MAX_ALG_NAME);
if (len + sizeof(suffix) > CRYPTO_MAX_ALG_NAME)
return -ENAMETOOLONG;
memcpy(driver_name + len, suffix, sizeof(suffix));
return 0;
}
static int crypto_check_alg(struct crypto_alg *alg)
{
if (alg->cra_alignmask & (alg->cra_alignmask + 1))
return -EINVAL;
if (alg->cra_alignmask & alg->cra_blocksize)
return -EINVAL;
if (alg->cra_blocksize > PAGE_SIZE / 8)
return -EINVAL;
if (alg->cra_priority < 0)
return -EINVAL;
return crypto_set_driver_name(alg);
}
static void crypto_destroy_instance(struct crypto_alg *alg)
{
struct crypto_instance *inst = (void *)alg;
struct crypto_template *tmpl = inst->tmpl;
tmpl->free(inst);
crypto_tmpl_put(tmpl);
}
static void crypto_remove_spawn(struct crypto_spawn *spawn,
struct list_head *list,
struct list_head *secondary_spawns)
{
struct crypto_instance *inst = spawn->inst;
struct crypto_template *tmpl = inst->tmpl;
list_del_init(&spawn->list);
spawn->alg = NULL;
if (crypto_is_dead(&inst->alg))
return;
inst->alg.cra_flags |= CRYPTO_ALG_DEAD;
if (!tmpl || !crypto_tmpl_get(tmpl))
return;
crypto_notify(CRYPTO_MSG_ALG_UNREGISTER, &inst->alg);
list_move(&inst->alg.cra_list, list);
hlist_del(&inst->list);
inst->alg.cra_destroy = crypto_destroy_instance;
list_splice(&inst->alg.cra_users, secondary_spawns);
}
static void crypto_remove_spawns(struct list_head *spawns,
struct list_head *list, u32 new_type)
{
struct crypto_spawn *spawn, *n;
LIST_HEAD(secondary_spawns);
list_for_each_entry_safe(spawn, n, spawns, list) {
if ((spawn->alg->cra_flags ^ new_type) & spawn->mask)
continue;
crypto_remove_spawn(spawn, list, &secondary_spawns);
}
while (!list_empty(&secondary_spawns)) {
list_for_each_entry_safe(spawn, n, &secondary_spawns, list)
crypto_remove_spawn(spawn, list, &secondary_spawns);
}
}
static int __crypto_register_alg(struct crypto_alg *alg,
struct list_head *list)
{
struct crypto_alg *q;
int ret = -EAGAIN;
if (crypto_is_dead(alg))
goto out;
INIT_LIST_HEAD(&alg->cra_users);
ret = -EEXIST;
atomic_set(&alg->cra_refcnt, 1);
list_for_each_entry(q, &crypto_alg_list, cra_list) {
if (q == alg)
goto out;
if (crypto_is_moribund(q))
continue;
if (crypto_is_larval(q)) {
struct crypto_larval *larval = (void *)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 (!crypto_mod_get(alg))
continue;
larval->adult = alg;
complete(&larval->completion);
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->cra_users, list, alg->cra_flags);
}
list_add(&alg->cra_list, &crypto_alg_list);
crypto_notify(CRYPTO_MSG_ALG_REGISTER, alg);
ret = 0;
out:
return ret;
}
static 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);
}
}
int crypto_register_alg(struct crypto_alg *alg)
{
LIST_HEAD(list);
int err;
err = crypto_check_alg(alg);
if (err)
return err;
down_write(&crypto_alg_sem);
err = __crypto_register_alg(alg, &list);
up_write(&crypto_alg_sem);
crypto_remove_final(&list);
return err;
}
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;
crypto_notify(CRYPTO_MSG_ALG_UNREGISTER, alg);
list_del_init(&alg->cra_list);
crypto_remove_spawns(&alg->cra_users, list, alg->cra_flags);
return 0;
}
int 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 (ret)
return ret;
BUG_ON(atomic_read(&alg->cra_refcnt) != 1);
if (alg->cra_destroy)
alg->cra_destroy(alg);
crypto_remove_final(&list);
return 0;
}
EXPORT_SYMBOL_GPL(crypto_unregister_alg);
int crypto_register_template(struct crypto_template *tmpl)
{
struct crypto_template *q;
int err = -EEXIST;
down_write(&crypto_alg_sem);
list_for_each_entry(q, &crypto_template_list, list) {
if (q == tmpl)
goto out;
}
list_add(&tmpl->list, &crypto_template_list);
crypto_notify(CRYPTO_MSG_TMPL_REGISTER, tmpl);
err = 0;
out:
up_write(&crypto_alg_sem);
return err;
}
EXPORT_SYMBOL_GPL(crypto_register_template);
void crypto_unregister_template(struct crypto_template *tmpl)
{
struct crypto_instance *inst;
struct hlist_node *p, *n;
struct hlist_head *list;
LIST_HEAD(users);
down_write(&crypto_alg_sem);
BUG_ON(list_empty(&tmpl->list));
list_del_init(&tmpl->list);
list = &tmpl->instances;
hlist_for_each_entry(inst, p, list, list) {
int err = crypto_remove_alg(&inst->alg, &users);
BUG_ON(err);
}
crypto_notify(CRYPTO_MSG_TMPL_UNREGISTER, tmpl);
up_write(&crypto_alg_sem);
hlist_for_each_entry_safe(inst, p, n, list, list) {
BUG_ON(atomic_read(&inst->alg.cra_refcnt) != 1);
tmpl->free(inst);
}
crypto_remove_final(&users);
}
EXPORT_SYMBOL_GPL(crypto_unregister_template);
static struct crypto_template *__crypto_lookup_template(const char *name)
{
struct crypto_template *q, *tmpl = NULL;
down_read(&crypto_alg_sem);
list_for_each_entry(q, &crypto_template_list, list) {
if (strcmp(q->name, name))
continue;
if (unlikely(!crypto_tmpl_get(q)))
continue;
tmpl = q;
break;
}
up_read(&crypto_alg_sem);
return tmpl;
}
struct crypto_template *crypto_lookup_template(const char *name)
{
return try_then_request_module(__crypto_lookup_template(name), name);
}
EXPORT_SYMBOL_GPL(crypto_lookup_template);
int crypto_register_instance(struct crypto_template *tmpl,
struct crypto_instance *inst)
{
LIST_HEAD(list);
int err = -EINVAL;
if (inst->alg.cra_destroy)
goto err;
err = crypto_check_alg(&inst->alg);
if (err)
goto err;
inst->alg.cra_module = tmpl->module;
down_write(&crypto_alg_sem);
err = __crypto_register_alg(&inst->alg, &list);
if (err)
goto unlock;
hlist_add_head(&inst->list, &tmpl->instances);
inst->tmpl = tmpl;
unlock:
up_write(&crypto_alg_sem);
crypto_remove_final(&list);
err:
return err;
}
EXPORT_SYMBOL_GPL(crypto_register_instance);
int crypto_init_spawn(struct crypto_spawn *spawn, struct crypto_alg *alg,
struct crypto_instance *inst, u32 mask)
{
int err = -EAGAIN;
spawn->inst = inst;
spawn->mask = mask;
down_write(&crypto_alg_sem);
if (!crypto_is_moribund(alg)) {
list_add(&spawn->list, &alg->cra_users);
spawn->alg = alg;
err = 0;
}
up_write(&crypto_alg_sem);
return err;
}
EXPORT_SYMBOL_GPL(crypto_init_spawn);
void crypto_drop_spawn(struct crypto_spawn *spawn)
{
down_write(&crypto_alg_sem);
list_del(&spawn->list);
up_write(&crypto_alg_sem);
}
EXPORT_SYMBOL_GPL(crypto_drop_spawn);
struct crypto_tfm *crypto_spawn_tfm(struct crypto_spawn *spawn, u32 type,
u32 mask)
{
struct crypto_alg *alg;
struct crypto_alg *alg2;
struct crypto_tfm *tfm;
down_read(&crypto_alg_sem);
alg = spawn->alg;
alg2 = alg;
if (alg2)
alg2 = crypto_mod_get(alg2);
up_read(&crypto_alg_sem);
if (!alg2) {
if (alg)
crypto_shoot_alg(alg);
return ERR_PTR(-EAGAIN);
}
tfm = ERR_PTR(-EINVAL);
if (unlikely((alg->cra_flags ^ type) & mask))
goto out_put_alg;
tfm = __crypto_alloc_tfm(alg, type, mask);
if (IS_ERR(tfm))
goto out_put_alg;
return tfm;
out_put_alg:
crypto_mod_put(alg);
return tfm;
}
EXPORT_SYMBOL_GPL(crypto_spawn_tfm);
int crypto_register_notifier(struct notifier_block *nb)
{
return blocking_notifier_chain_register(&crypto_chain, nb);
}
EXPORT_SYMBOL_GPL(crypto_register_notifier);
int crypto_unregister_notifier(struct notifier_block *nb)
{
return blocking_notifier_chain_unregister(&crypto_chain, nb);
}
EXPORT_SYMBOL_GPL(crypto_unregister_notifier);
struct crypto_attr_type *crypto_get_attr_type(struct rtattr **tb)
{
struct rtattr *rta = tb[CRYPTOA_TYPE - 1];
struct crypto_attr_type *algt;
if (!rta)
return ERR_PTR(-ENOENT);
if (RTA_PAYLOAD(rta) < sizeof(*algt))
return ERR_PTR(-EINVAL);
algt = RTA_DATA(rta);
return algt;
}
EXPORT_SYMBOL_GPL(crypto_get_attr_type);
int crypto_check_attr_type(struct rtattr **tb, u32 type)
{
struct crypto_attr_type *algt;
algt = crypto_get_attr_type(tb);
if (IS_ERR(algt))
return PTR_ERR(algt);
if ((algt->type ^ type) & algt->mask)
return -EINVAL;
return 0;
}
EXPORT_SYMBOL_GPL(crypto_check_attr_type);
struct crypto_alg *crypto_get_attr_alg(struct rtattr **tb, u32 type, u32 mask)
{
struct rtattr *rta = tb[CRYPTOA_ALG - 1];
struct crypto_attr_alg *alga;
if (!rta)
return ERR_PTR(-ENOENT);
if (RTA_PAYLOAD(rta) < sizeof(*alga))
return ERR_PTR(-EINVAL);
alga = RTA_DATA(rta);
alga->name[CRYPTO_MAX_ALG_NAME - 1] = 0;
return crypto_alg_mod_lookup(alga->name, type, mask);
}
EXPORT_SYMBOL_GPL(crypto_get_attr_alg);
struct crypto_instance *crypto_alloc_instance(const char *name,
struct crypto_alg *alg)
{
struct crypto_instance *inst;
struct crypto_spawn *spawn;
int err;
inst = kzalloc(sizeof(*inst) + sizeof(*spawn), GFP_KERNEL);
if (!inst)
return ERR_PTR(-ENOMEM);
err = -ENAMETOOLONG;
if (snprintf(inst->alg.cra_name, CRYPTO_MAX_ALG_NAME, "%s(%s)", name,
alg->cra_name) >= CRYPTO_MAX_ALG_NAME)
goto err_free_inst;
if (snprintf(inst->alg.cra_driver_name, CRYPTO_MAX_ALG_NAME, "%s(%s)",
name, alg->cra_driver_name) >= CRYPTO_MAX_ALG_NAME)
goto err_free_inst;
spawn = crypto_instance_ctx(inst);
err = crypto_init_spawn(spawn, alg, inst,
CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_ASYNC);
if (err)
goto err_free_inst;
return inst;
err_free_inst:
kfree(inst);
return ERR_PTR(err);
}
EXPORT_SYMBOL_GPL(crypto_alloc_instance);
void crypto_init_queue(struct crypto_queue *queue, unsigned int max_qlen)
{
INIT_LIST_HEAD(&queue->list);
queue->backlog = &queue->list;
queue->qlen = 0;
queue->max_qlen = max_qlen;
}
EXPORT_SYMBOL_GPL(crypto_init_queue);
int crypto_enqueue_request(struct crypto_queue *queue,
struct crypto_async_request *request)
{
int err = -EINPROGRESS;
if (unlikely(queue->qlen >= queue->max_qlen)) {
err = -EBUSY;
if (!(request->flags & CRYPTO_TFM_REQ_MAY_BACKLOG))
goto out;
if (queue->backlog == &queue->list)
queue->backlog = &request->list;
}
queue->qlen++;
list_add_tail(&request->list, &queue->list);
out:
return err;
}
EXPORT_SYMBOL_GPL(crypto_enqueue_request);
struct crypto_async_request *crypto_dequeue_request(struct crypto_queue *queue)
{
struct list_head *request;
if (unlikely(!queue->qlen))
return NULL;
queue->qlen--;
if (queue->backlog != &queue->list)
queue->backlog = queue->backlog->next;
request = queue->list.next;
list_del(request);
return list_entry(request, struct crypto_async_request, list);
}
EXPORT_SYMBOL_GPL(crypto_dequeue_request);
int crypto_tfm_in_queue(struct crypto_queue *queue, struct crypto_tfm *tfm)
{
struct crypto_async_request *req;
list_for_each_entry(req, &queue->list, list) {
if (req->tfm == tfm)
return 1;
}
return 0;
}
EXPORT_SYMBOL_GPL(crypto_tfm_in_queue);
static int __init crypto_algapi_init(void)
{
crypto_init_proc();
return 0;
}
static void __exit crypto_algapi_exit(void)
{
crypto_exit_proc();
}
module_init(crypto_algapi_init);
module_exit(crypto_algapi_exit);
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Cryptographic algorithms API");