crypto/algapi.c

   1 /*
   2  * Cryptographic API for algorithms (i.e., low-level API).
   3  *
   4  * Copyright (c) 2006 Herbert Xu <herbert@gondor.apana.org.au>
   5  *
   6  * This program is free software; you can redistribute it and/or modify it
   7  * under the terms of the GNU General Public License as published by the Free
   8  * Software Foundation; either version 2 of the License, or (at your option)
   9  * any later version.
  10  *
  11  */
  12
  13 #include <linux/errno.h>
  14 #include <linux/init.h>
  15 #include <linux/kernel.h>
  16 #include <linux/module.h>
  17 #include <linux/string.h>
  18
  19 #include "internal.h"
  20
  21 static inline int crypto_set_driver_name(struct crypto_alg *alg)
  22 {
  23         static const char suffix[] = "-generic";
  24         char *driver_name = alg->cra_driver_name;
  25         int len;
  26
  27         if (*driver_name)
  28                 return 0;
  29
  30         len = strlcpy(driver_name, alg->cra_name, CRYPTO_MAX_ALG_NAME);
  31         if (len + sizeof(suffix) > CRYPTO_MAX_ALG_NAME)
  32                 return -ENAMETOOLONG;
  33
  34         memcpy(driver_name + len, suffix, sizeof(suffix));
  35         return 0;
  36 }
  37
  38 int crypto_register_alg(struct crypto_alg *alg)
  39 {
  40         int ret;
  41         struct crypto_alg *q;
  42
  43         if (alg->cra_alignmask & (alg->cra_alignmask + 1))
  44                 return -EINVAL;
  45
  46         if (alg->cra_alignmask & alg->cra_blocksize)
  47                 return -EINVAL;
  48
  49         if (alg->cra_blocksize > PAGE_SIZE / 8)
  50                 return -EINVAL;
  51
  52         if (alg->cra_priority < 0)
  53                 return -EINVAL;
  54
  55         ret = crypto_set_driver_name(alg);
  56         if (unlikely(ret))
  57                 return ret;
  58
  59         down_write(&crypto_alg_sem);
  60
  61         list_for_each_entry(q, &crypto_alg_list, cra_list) {
  62                 if (q == alg) {
  63                         ret = -EEXIST;
  64                         goto out;
  65                 }
  66         }
  67
  68         list_add(&alg->cra_list, &crypto_alg_list);
  69         atomic_set(&alg->cra_refcnt, 1);
  70 out:
  71         up_write(&crypto_alg_sem);
  72         return ret;
  73 }
  74 EXPORT_SYMBOL_GPL(crypto_register_alg);
  75
  76 int crypto_unregister_alg(struct crypto_alg *alg)
  77 {
  78         int ret = -ENOENT;
  79         struct crypto_alg *q;
  80
  81         down_write(&crypto_alg_sem);
  82         list_for_each_entry(q, &crypto_alg_list, cra_list) {
  83                 if (alg == q) {
  84                         list_del(&alg->cra_list);
  85                         ret = 0;
  86                         goto out;
  87                 }
  88         }
  89 out:
  90         up_write(&crypto_alg_sem);
  91
  92         if (ret)
  93                 return ret;
  94
  95         BUG_ON(atomic_read(&alg->cra_refcnt) != 1);
  96         if (alg->cra_destroy)
  97                 alg->cra_destroy(alg);
  98
  99         return 0;
 100 }
 101 EXPORT_SYMBOL_GPL(crypto_unregister_alg);
 102
 103 static int __init crypto_algapi_init(void)
 104 {
 105         crypto_init_proc();
 106         return 0;
 107 }
 108
 109 static void __exit crypto_algapi_exit(void)
 110 {
 111         crypto_exit_proc();
 112 }
 113
 114 module_init(crypto_algapi_init);
 115 module_exit(crypto_algapi_exit);
 116
 117 MODULE_LICENSE("GPL");
 118 MODULE_DESCRIPTION("Cryptographic algorithms API");