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cryptomgr.c

/*
 * Create default crypto algorithm instances.
 *
 * 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/crypto.h>
#include <linux/ctype.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/kthread.h>
#include <linux/module.h>
#include <linux/notifier.h>
#include <linux/rtnetlink.h>
#include <linux/sched.h>
#include <linux/string.h>

#include "internal.h"

struct cryptomgr_param {
      struct rtattr *tb[CRYPTO_MAX_ATTRS + 2];

      struct {
            struct rtattr attr;
            struct crypto_attr_type data;
      } type;

      union {
            struct rtattr attr;
            struct {
                  struct rtattr attr;
                  struct crypto_attr_alg data;
            } alg;
            struct {
                  struct rtattr attr;
                  struct crypto_attr_u32 data;
            } nu32;
      } attrs[CRYPTO_MAX_ATTRS];

      char larval[CRYPTO_MAX_ALG_NAME];
      char template[CRYPTO_MAX_ALG_NAME];
};

static int cryptomgr_probe(void *data)
{
      struct cryptomgr_param *param = data;
      struct crypto_template *tmpl;
      struct crypto_instance *inst;
      int err;

      tmpl = crypto_lookup_template(param->template);
      if (!tmpl)
            goto err;

      do {
            inst = tmpl->alloc(param->tb);
            if (IS_ERR(inst))
                  err = PTR_ERR(inst);
            else if ((err = crypto_register_instance(tmpl, inst)))
                  tmpl->free(inst);
      } while (err == -EAGAIN && !signal_pending(current));

      crypto_tmpl_put(tmpl);

      if (err)
            goto err;

out:
      kfree(param);
      module_put_and_exit(0);

err:
      crypto_larval_error(param->larval, param->type.data.type,
                      param->type.data.mask);
      goto out;
}

static int cryptomgr_schedule_probe(struct crypto_larval *larval)
{
      struct task_struct *thread;
      struct cryptomgr_param *param;
      const char *name = larval->alg.cra_name;
      const char *p;
      unsigned int len;
      int i;

      if (!try_module_get(THIS_MODULE))
            goto err;

      param = kzalloc(sizeof(*param), GFP_KERNEL);
      if (!param)
            goto err_put_module;

      for (p = name; isalnum(*p) || *p == '-' || *p == '_'; p++)
            ;

      len = p - name;
      if (!len || *p != '(')
            goto err_free_param;

      memcpy(param->template, name, len);

      i = 0;
      for (;;) {
            int notnum = 0;

            name = ++p;
            len = 0;

            for (; isalnum(*p) || *p == '-' || *p == '_'; p++)
                  notnum |= !isdigit(*p);

            if (*p == '(') {
                  int recursion = 0;

                  for (;;) {
                        if (!*++p)
                              goto err_free_param;
                        if (*p == '(')
                              recursion++;
                        else if (*p == ')' && !recursion--)
                              break;
                  }

                  notnum = 1;
                  p++;
            }

            len = p - name;
            if (!len)
                  goto err_free_param;

            if (notnum) {
                  param->attrs[i].alg.attr.rta_len =
                        sizeof(param->attrs[i].alg);
                  param->attrs[i].alg.attr.rta_type = CRYPTOA_ALG;
                  memcpy(param->attrs[i].alg.data.name, name, len);
            } else {
                  param->attrs[i].nu32.attr.rta_len =
                        sizeof(param->attrs[i].nu32);
                  param->attrs[i].nu32.attr.rta_type = CRYPTOA_U32;
                  param->attrs[i].nu32.data.num =
                        simple_strtol(name, NULL, 0);
            }

            param->tb[i + 1] = &param->attrs[i].attr;
            i++;

            if (i >= CRYPTO_MAX_ATTRS)
                  goto err_free_param;

            if (*p == ')')
                  break;

            if (*p != ',')
                  goto err_free_param;
      }

      if (!i)
            goto err_free_param;

      param->tb[i + 1] = NULL;

      param->type.attr.rta_len = sizeof(param->type);
      param->type.attr.rta_type = CRYPTOA_TYPE;
      param->type.data.type = larval->alg.cra_flags;
      param->type.data.mask = larval->mask;
      param->tb[0] = &param->type.attr;

      memcpy(param->larval, larval->alg.cra_name, CRYPTO_MAX_ALG_NAME);

      thread = kthread_run(cryptomgr_probe, param, "cryptomgr");
      if (IS_ERR(thread))
            goto err_free_param;

      return NOTIFY_STOP;

err_free_param:
      kfree(param);
err_put_module:
      module_put(THIS_MODULE);
err:
      return NOTIFY_OK;
}

static int cryptomgr_notify(struct notifier_block *this, unsigned long msg,
                      void *data)
{
      switch (msg) {
      case CRYPTO_MSG_ALG_REQUEST:
            return cryptomgr_schedule_probe(data);
      }

      return NOTIFY_DONE;
}

static struct notifier_block cryptomgr_notifier = {
      .notifier_call = cryptomgr_notify,
};

static int __init cryptomgr_init(void)
{
      return crypto_register_notifier(&cryptomgr_notifier);
}

static void __exit cryptomgr_exit(void)
{
      int err = crypto_unregister_notifier(&cryptomgr_notifier);
      BUG_ON(err);
}

module_init(cryptomgr_init);
module_exit(cryptomgr_exit);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Crypto Algorithm Manager");

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