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 17 #include <linux/compiler.h> 18 #include <linux/init.h> 19 #include <linux/crypto.h> 20 #include <linux/errno.h> 21 #include <linux/kmod.h> 22 #include <linux/rwsem.h> 23 #include <linux/slab.h> 24 #include "internal.h" 25 26 LIST_HEAD(crypto_alg_list); 27 DECLARE_RWSEM(crypto_alg_sem); 28 29 static inline int crypto_alg_get(struct crypto_alg *alg) 30 { 31 return try_module_get(alg->cra_module); 32 } 33 34 static inline void crypto_alg_put(struct crypto_alg *alg) 35 { 36 module_put(alg->cra_module); 37 } 38 39 static struct crypto_alg *crypto_alg_lookup(const char *name) 40 { 41 struct crypto_alg *q, *alg = NULL; 42 43 if (!name) 44 return NULL; 45 46 down_read(&crypto_alg_sem); 47 48 list_for_each_entry(q, &crypto_alg_list, cra_list) { 49 if (!(strcmp(q->cra_name, name))) { 50 if (crypto_alg_get(q)) 51 alg = q; 52 break; 53 } 54 } 55 56 up_read(&crypto_alg_sem); 57 return alg; 58 } 59 60 /* A far more intelligent version of this is planned. For now, just 61 * try an exact match on the name of the algorithm. */ 62 static inline struct crypto_alg *crypto_alg_mod_lookup(const char *name) 63 { 64 return try_then_request_module(crypto_alg_lookup(name), name); 65 } 66 67 static int crypto_init_flags(struct crypto_tfm *tfm, u32 flags) 68 { 69 tfm->crt_flags = 0; 70 71 switch (crypto_tfm_alg_type(tfm)) { 72 case CRYPTO_ALG_TYPE_CIPHER: 73 return crypto_init_cipher_flags(tfm, flags); 74 75 case CRYPTO_ALG_TYPE_DIGEST: 76 return crypto_init_digest_flags(tfm, flags); 77 78 case CRYPTO_ALG_TYPE_COMPRESS: 79 return crypto_init_compress_flags(tfm, flags); 80 81 default: 82 break; 83 } 84 85 BUG(); 86 return -EINVAL; 87 } 88 89 static int crypto_init_ops(struct crypto_tfm *tfm) 90 { 91 switch (crypto_tfm_alg_type(tfm)) { 92 case CRYPTO_ALG_TYPE_CIPHER: 93 return crypto_init_cipher_ops(tfm); 94 95 case CRYPTO_ALG_TYPE_DIGEST: 96 return crypto_init_digest_ops(tfm); 97 98 case CRYPTO_ALG_TYPE_COMPRESS: 99 return crypto_init_compress_ops(tfm); 100 101 default: 102 break; 103 } 104 105 BUG(); 106 return -EINVAL; 107 } 108 109 static void crypto_exit_ops(struct crypto_tfm *tfm) 110 { 111 switch (crypto_tfm_alg_type(tfm)) { 112 case CRYPTO_ALG_TYPE_CIPHER: 113 crypto_exit_cipher_ops(tfm); 114 break; 115 116 case CRYPTO_ALG_TYPE_DIGEST: 117 crypto_exit_digest_ops(tfm); 118 break; 119 120 case CRYPTO_ALG_TYPE_COMPRESS: 121 crypto_exit_compress_ops(tfm); 122 break; 123 124 default: 125 BUG(); 126 127 } 128 } 129 130 static unsigned int crypto_ctxsize(struct crypto_alg *alg, int flags) 131 { 132 unsigned int len; 133 134 switch (alg->cra_flags & CRYPTO_ALG_TYPE_MASK) { 135 default: 136 BUG(); 137 138 case CRYPTO_ALG_TYPE_CIPHER: 139 len = crypto_cipher_ctxsize(alg, flags); 140 break; 141 142 case CRYPTO_ALG_TYPE_DIGEST: 143 len = crypto_digest_ctxsize(alg, flags); 144 break; 145 146 case CRYPTO_ALG_TYPE_COMPRESS: 147 len = crypto_compress_ctxsize(alg, flags); 148 break; 149 } 150 151 return len + alg->cra_alignmask; 152 } 153 154 struct crypto_tfm *crypto_alloc_tfm(const char *name, u32 flags) 155 { 156 struct crypto_tfm *tfm = NULL; 157 struct crypto_alg *alg; 158 unsigned int tfm_size; 159 160 alg = crypto_alg_mod_lookup(name); 161 if (alg == NULL) 162 goto out; 163 164 tfm_size = sizeof(*tfm) + crypto_ctxsize(alg, flags); 165 tfm = kmalloc(tfm_size, GFP_KERNEL); 166 if (tfm == NULL) 167 goto out_put; 168 169 memset(tfm, 0, tfm_size); 170 171 tfm->__crt_alg = alg; 172 173 if (crypto_init_flags(tfm, flags)) 174 goto out_free_tfm; 175 176 if (crypto_init_ops(tfm)) { 177 crypto_exit_ops(tfm); 178 goto out_free_tfm; 179 } 180 181 goto out; 182 183 out_free_tfm: 184 kfree(tfm); 185 tfm = NULL; 186 out_put: 187 crypto_alg_put(alg); 188 out: 189 return tfm; 190 } 191 192 void crypto_free_tfm(struct crypto_tfm *tfm) 193 { 194 struct crypto_alg *alg; 195 int size; 196 197 if (unlikely(!tfm)) 198 return; 199 200 alg = tfm->__crt_alg; 201 size = sizeof(*tfm) + alg->cra_ctxsize; 202 203 crypto_exit_ops(tfm); 204 crypto_alg_put(alg); 205 memset(tfm, 0, size); 206 kfree(tfm); 207 } 208 209 int crypto_register_alg(struct crypto_alg *alg) 210 { 211 int ret = 0; 212 struct crypto_alg *q; 213 214 if (alg->cra_alignmask & (alg->cra_alignmask + 1)) 215 return -EINVAL; 216 217 if (alg->cra_alignmask > PAGE_SIZE) 218 return -EINVAL; 219 220 down_write(&crypto_alg_sem); 221 222 list_for_each_entry(q, &crypto_alg_list, cra_list) { 223 if (!(strcmp(q->cra_name, alg->cra_name))) { 224 ret = -EEXIST; 225 goto out; 226 } 227 } 228 229 list_add_tail(&alg->cra_list, &crypto_alg_list); 230 out: 231 up_write(&crypto_alg_sem); 232 return ret; 233 } 234 235 int crypto_unregister_alg(struct crypto_alg *alg) 236 { 237 int ret = -ENOENT; 238 struct crypto_alg *q; 239 240 BUG_ON(!alg->cra_module); 241 242 down_write(&crypto_alg_sem); 243 list_for_each_entry(q, &crypto_alg_list, cra_list) { 244 if (alg == q) { 245 list_del(&alg->cra_list); 246 ret = 0; 247 goto out; 248 } 249 } 250 out: 251 up_write(&crypto_alg_sem); 252 return ret; 253 } 254 255 int crypto_alg_available(const char *name, u32 flags) 256 { 257 int ret = 0; 258 struct crypto_alg *alg = crypto_alg_mod_lookup(name); 259 260 if (alg) { 261 crypto_alg_put(alg); 262 ret = 1; 263 } 264 265 return ret; 266 } 267 268 static int __init init_crypto(void) 269 { 270 printk(KERN_INFO "Initializing Cryptographic API\n"); 271 crypto_init_proc(); 272 return 0; 273 } 274 275 __initcall(init_crypto); 276 277 EXPORT_SYMBOL_GPL(crypto_register_alg); 278 EXPORT_SYMBOL_GPL(crypto_unregister_alg); 279 EXPORT_SYMBOL_GPL(crypto_alloc_tfm); 280 EXPORT_SYMBOL_GPL(crypto_free_tfm); 281 EXPORT_SYMBOL_GPL(crypto_alg_available); 282