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algapi.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_all(&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_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 (hlist_unhashed(&inst->list))
            return;

      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;

                  /*
                   * 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 (!crypto_mod_get(alg))
                        continue;

                  larval->adult = alg;
                  complete_all(&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;

      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[0];
      struct crypto_attr_type *algt;

      if (!rta)
            return ERR_PTR(-ENOENT);
      if (RTA_PAYLOAD(rta) < sizeof(*algt))
            return ERR_PTR(-EINVAL);
      if (rta->rta_type != CRYPTOA_TYPE)
            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_attr_alg(struct rtattr *rta, u32 type, u32 mask)
{
      struct crypto_attr_alg *alga;

      if (!rta)
            return ERR_PTR(-ENOENT);
      if (RTA_PAYLOAD(rta) < sizeof(*alga))
            return ERR_PTR(-EINVAL);
      if (rta->rta_type != CRYPTOA_ALG)
            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_attr_alg);

int crypto_attr_u32(struct rtattr *rta, u32 *num)
{
      struct crypto_attr_u32 *nu32;

      if (!rta)
            return -ENOENT;
      if (RTA_PAYLOAD(rta) < sizeof(*nu32))
            return -EINVAL;
      if (rta->rta_type != CRYPTOA_U32)
            return -EINVAL;

      nu32 = RTA_DATA(rta);
      *num = nu32->num;

      return 0;
}
EXPORT_SYMBOL_GPL(crypto_attr_u32);

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");

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