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 M�ller. 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); 234