crypto/api.c

   1 /*
   2  * Scatterlist Cryptographic API.
   3  *
   4  * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
   5  * Copyright (c) 2002 David S. Miller (davem@redhat.com)
   6  *
   7  * Portions derived from Cryptoapi, by Alexander Kjeldaas <astor@fast.no>
   8  * and Nettle, by Niels Möller.
   9  *
  10  * This program is free software; you can redistribute it and/or modify it
  11  * under the terms of the GNU General Public License as published by the Free
  12  * Software Foundation; either version 2 of the License, or (at your option)
  13  * any later version.
  14  *
  15  */
  16 #include <linux/init.h>
  17 #include <linux/crypto.h>
  18 #include <linux/errno.h>
  19 #include <linux/rwsem.h>
  20 #include <linux/slab.h>
  21 #include "internal.h"
  22
  23 LIST_HEAD(crypto_alg_list);
  24 DECLARE_RWSEM(crypto_alg_sem);
  25
  26 static inline int crypto_alg_get(struct crypto_alg *alg)
  27 {
  28         return try_module_get(alg->cra_module);
  29 }
  30
  31 static inline void crypto_alg_put(struct crypto_alg *alg)
  32 {
  33         module_put(alg->cra_module);
  34 }
  35
  36 struct crypto_alg *crypto_alg_lookup(const char *name)
  37 {
  38         struct crypto_alg *q, *alg = NULL;
  39
  40         if (!name)
  41                 return NULL;
  42
  43         down_read(&crypto_alg_sem);
  44
  45         list_for_each_entry(q, &crypto_alg_list, cra_list) {
  46                 if (!(strcmp(q->cra_name, name))) {
  47                         if (crypto_alg_get(q))
  48                                 alg = q;
  49                         break;
  50                 }
  51         }
  52
  53         up_read(&crypto_alg_sem);
  54         return alg;
  55 }
  56
  57 static int crypto_init_flags(struct crypto_tfm *tfm, u32 flags)
  58 {
  59         tfm->crt_flags = 0;
  60
  61         switch (crypto_tfm_alg_type(tfm)) {
  62         case CRYPTO_ALG_TYPE_CIPHER:
  63                 return crypto_init_cipher_flags(tfm, flags);
  64
  65         case CRYPTO_ALG_TYPE_DIGEST:
  66                 return crypto_init_digest_flags(tfm, flags);
  67
  68         case CRYPTO_ALG_TYPE_COMPRESS:
  69                 return crypto_init_compress_flags(tfm, flags);
  70
  71         default:
  72                 break;
  73         }
  74
  75         BUG();
  76         return -EINVAL;
  77 }
  78
  79 static int crypto_init_ops(struct crypto_tfm *tfm)
  80 {
  81         switch (crypto_tfm_alg_type(tfm)) {
  82         case CRYPTO_ALG_TYPE_CIPHER:
  83                 return crypto_init_cipher_ops(tfm);
  84
  85         case CRYPTO_ALG_TYPE_DIGEST:
  86                 return crypto_init_digest_ops(tfm);
  87
  88         case CRYPTO_ALG_TYPE_COMPRESS:
  89                 return crypto_init_compress_ops(tfm);
  90
  91         default:
  92                 break;
  93         }
  94
  95         BUG();
  96         return -EINVAL;
  97 }
  98
  99 static void crypto_exit_ops(struct crypto_tfm *tfm)
 100 {
 101         switch (crypto_tfm_alg_type(tfm)) {
 102         case CRYPTO_ALG_TYPE_CIPHER:
 103                 crypto_exit_cipher_ops(tfm);
 104                 break;
 105
 106         case CRYPTO_ALG_TYPE_DIGEST:
 107                 crypto_exit_digest_ops(tfm);
 108                 break;
 109
 110         case CRYPTO_ALG_TYPE_COMPRESS:
 111                 crypto_exit_compress_ops(tfm);
 112                 break;
 113
 114         default:
 115                 BUG();
 116
 117         }
 118 }
 119
 120 struct crypto_tfm *crypto_alloc_tfm(const char *name, u32 flags)
 121 {
 122         struct crypto_tfm *tfm = NULL;
 123         struct crypto_alg *alg;
 124
 125         alg = crypto_alg_mod_lookup(name);
 126         if (alg == NULL)
 127                 goto out;
 128
 129         tfm = kmalloc(sizeof(*tfm) + alg->cra_ctxsize, GFP_KERNEL);
 130         if (tfm == NULL)
 131                 goto out_put;
 132
 133         memset(tfm, 0, sizeof(*tfm) + alg->cra_ctxsize);
 134
 135         tfm->__crt_alg = alg;
 136
 137         if (crypto_init_flags(tfm, flags))
 138                 goto out_free_tfm;
 139
 140         if (crypto_init_ops(tfm)) {
 141                 crypto_exit_ops(tfm);
 142                 goto out_free_tfm;
 143         }
 144
 145         goto out;
 146
 147 out_free_tfm:
 148         kfree(tfm);
 149         tfm = NULL;
 150 out_put:
 151         crypto_alg_put(alg);
 152 out:
 153         return tfm;
 154 }
 155
 156 void crypto_free_tfm(struct crypto_tfm *tfm)
 157 {
 158         struct crypto_alg *alg = tfm->__crt_alg;
 159         int size = sizeof(*tfm) + alg->cra_ctxsize;
 160
 161         crypto_exit_ops(tfm);
 162         crypto_alg_put(alg);
 163         memset(tfm, 0, size);
 164         kfree(tfm);
 165 }
 166
 167 int crypto_register_alg(struct crypto_alg *alg)
 168 {
 169         int ret = 0;
 170         struct crypto_alg *q;
 171
 172         down_write(&crypto_alg_sem);
 173
 174         list_for_each_entry(q, &crypto_alg_list, cra_list) {
 175                 if (!(strcmp(q->cra_name, alg->cra_name))) {
 176                         ret = -EEXIST;
 177                         goto out;
 178                 }
 179         }
 180
 181         list_add_tail(&alg->cra_list, &crypto_alg_list);
 182 out:
 183         up_write(&crypto_alg_sem);
 184         return ret;
 185 }
 186
 187 int crypto_unregister_alg(struct crypto_alg *alg)
 188 {
 189         int ret = -ENOENT;
 190         struct crypto_alg *q;
 191
 192         BUG_ON(!alg->cra_module);
 193
 194         down_write(&crypto_alg_sem);
 195         list_for_each_entry(q, &crypto_alg_list, cra_list) {
 196                 if (alg == q) {
 197                         list_del(&alg->cra_list);
 198                         ret = 0;
 199                         goto out;
 200                 }
 201         }
 202 out:
 203         up_write(&crypto_alg_sem);
 204         return ret;
 205 }
 206
 207 int crypto_alg_available(const char *name, u32 flags)
 208 {
 209         int ret = 0;
 210         struct crypto_alg *alg = crypto_alg_mod_lookup(name);
 211
 212         if (alg) {
 213                 crypto_alg_put(alg);
 214                 ret = 1;
 215         }
 216
 217         return ret;
 218 }
 219
 220 static int __init init_crypto(void)
 221 {
 222         printk(KERN_INFO "Initializing Cryptographic API\n");
 223         crypto_init_proc();
 224         return 0;
 225 }
 226
 227 __initcall(init_crypto);
 228
 229 EXPORT_SYMBOL_GPL(crypto_register_alg);
 230 EXPORT_SYMBOL_GPL(crypto_unregister_alg);
 231 EXPORT_SYMBOL_GPL(crypto_alloc_tfm);
 232 EXPORT_SYMBOL_GPL(crypto_free_tfm);
 233 EXPORT_SYMBOL_GPL(crypto_alg_available);