api.c 5.3 KB
Newer Older
L
Linus Torvalds 已提交
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
/*
 * Scatterlist Cryptographic API.
 *
 * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
 * Copyright (c) 2002 David S. Miller (davem@redhat.com)
 *
 * Portions derived from Cryptoapi, by Alexander Kjeldaas <astor@fast.no>
 * and Nettle, by Niels Mller.
 *
 * 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.
 *
 */
16 17

#include <linux/compiler.h>
L
Linus Torvalds 已提交
18 19 20
#include <linux/init.h>
#include <linux/crypto.h>
#include <linux/errno.h>
21
#include <linux/kmod.h>
L
Linus Torvalds 已提交
22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38
#include <linux/rwsem.h>
#include <linux/slab.h>
#include "internal.h"

LIST_HEAD(crypto_alg_list);
DECLARE_RWSEM(crypto_alg_sem);

static inline int crypto_alg_get(struct crypto_alg *alg)
{
	return try_module_get(alg->cra_module);
}

static inline void crypto_alg_put(struct crypto_alg *alg)
{
	module_put(alg->cra_module);
}

39
static struct crypto_alg *crypto_alg_lookup(const char *name)
L
Linus Torvalds 已提交
40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59
{
	struct crypto_alg *q, *alg = NULL;

	if (!name)
		return NULL;
	
	down_read(&crypto_alg_sem);
	
	list_for_each_entry(q, &crypto_alg_list, cra_list) {
		if (!(strcmp(q->cra_name, name))) {
			if (crypto_alg_get(q))
				alg = q;
			break;
		}
	}
	
	up_read(&crypto_alg_sem);
	return alg;
}

60 61 62 63 64 65 66
/* A far more intelligent version of this is planned.  For now, just
 * try an exact match on the name of the algorithm. */
static inline struct crypto_alg *crypto_alg_mod_lookup(const char *name)
{
	return try_then_request_module(crypto_alg_lookup(name), name);
}

L
Linus Torvalds 已提交
67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129
static int crypto_init_flags(struct crypto_tfm *tfm, u32 flags)
{
	tfm->crt_flags = 0;
	
	switch (crypto_tfm_alg_type(tfm)) {
	case CRYPTO_ALG_TYPE_CIPHER:
		return crypto_init_cipher_flags(tfm, flags);
		
	case CRYPTO_ALG_TYPE_DIGEST:
		return crypto_init_digest_flags(tfm, flags);
		
	case CRYPTO_ALG_TYPE_COMPRESS:
		return crypto_init_compress_flags(tfm, flags);
	
	default:
		break;
	}
	
	BUG();
	return -EINVAL;
}

static int crypto_init_ops(struct crypto_tfm *tfm)
{
	switch (crypto_tfm_alg_type(tfm)) {
	case CRYPTO_ALG_TYPE_CIPHER:
		return crypto_init_cipher_ops(tfm);
		
	case CRYPTO_ALG_TYPE_DIGEST:
		return crypto_init_digest_ops(tfm);
		
	case CRYPTO_ALG_TYPE_COMPRESS:
		return crypto_init_compress_ops(tfm);
	
	default:
		break;
	}
	
	BUG();
	return -EINVAL;
}

static void crypto_exit_ops(struct crypto_tfm *tfm)
{
	switch (crypto_tfm_alg_type(tfm)) {
	case CRYPTO_ALG_TYPE_CIPHER:
		crypto_exit_cipher_ops(tfm);
		break;
		
	case CRYPTO_ALG_TYPE_DIGEST:
		crypto_exit_digest_ops(tfm);
		break;
		
	case CRYPTO_ALG_TYPE_COMPRESS:
		crypto_exit_compress_ops(tfm);
		break;
	
	default:
		BUG();
		
	}
}

130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153
static unsigned int crypto_ctxsize(struct crypto_alg *alg, int flags)
{
	unsigned int len;

	switch (alg->cra_flags & CRYPTO_ALG_TYPE_MASK) {
	default:
		BUG();

	case CRYPTO_ALG_TYPE_CIPHER:
		len = crypto_cipher_ctxsize(alg, flags);
		break;
		
	case CRYPTO_ALG_TYPE_DIGEST:
		len = crypto_digest_ctxsize(alg, flags);
		break;
		
	case CRYPTO_ALG_TYPE_COMPRESS:
		len = crypto_compress_ctxsize(alg, flags);
		break;
	}

	return len + alg->cra_alignmask;
}

L
Linus Torvalds 已提交
154 155 156 157
struct crypto_tfm *crypto_alloc_tfm(const char *name, u32 flags)
{
	struct crypto_tfm *tfm = NULL;
	struct crypto_alg *alg;
158
	unsigned int tfm_size;
L
Linus Torvalds 已提交
159 160 161 162

	alg = crypto_alg_mod_lookup(name);
	if (alg == NULL)
		goto out;
163 164 165

	tfm_size = sizeof(*tfm) + crypto_ctxsize(alg, flags);
	tfm = kmalloc(tfm_size, GFP_KERNEL);
L
Linus Torvalds 已提交
166 167 168
	if (tfm == NULL)
		goto out_put;

169
	memset(tfm, 0, tfm_size);
L
Linus Torvalds 已提交
170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193
	
	tfm->__crt_alg = alg;
	
	if (crypto_init_flags(tfm, flags))
		goto out_free_tfm;
		
	if (crypto_init_ops(tfm)) {
		crypto_exit_ops(tfm);
		goto out_free_tfm;
	}

	goto out;

out_free_tfm:
	kfree(tfm);
	tfm = NULL;
out_put:
	crypto_alg_put(alg);
out:
	return tfm;
}

void crypto_free_tfm(struct crypto_tfm *tfm)
{
194 195 196 197 198 199 200 201
	struct crypto_alg *alg;
	int size;

	if (unlikely(!tfm))
		return;

	alg = tfm->__crt_alg;
	size = sizeof(*tfm) + alg->cra_ctxsize;
L
Linus Torvalds 已提交
202 203 204 205 206 207 208 209 210 211 212

	crypto_exit_ops(tfm);
	crypto_alg_put(alg);
	memset(tfm, 0, size);
	kfree(tfm);
}

int crypto_register_alg(struct crypto_alg *alg)
{
	int ret = 0;
	struct crypto_alg *q;
213 214 215 216 217 218

	if (alg->cra_alignmask & (alg->cra_alignmask + 1))
		return -EINVAL;

	if (alg->cra_alignmask > PAGE_SIZE)
		return -EINVAL;
L
Linus Torvalds 已提交
219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281
	
	down_write(&crypto_alg_sem);
	
	list_for_each_entry(q, &crypto_alg_list, cra_list) {
		if (!(strcmp(q->cra_name, alg->cra_name))) {
			ret = -EEXIST;
			goto out;
		}
	}
	
	list_add_tail(&alg->cra_list, &crypto_alg_list);
out:	
	up_write(&crypto_alg_sem);
	return ret;
}

int crypto_unregister_alg(struct crypto_alg *alg)
{
	int ret = -ENOENT;
	struct crypto_alg *q;
	
	BUG_ON(!alg->cra_module);
	
	down_write(&crypto_alg_sem);
	list_for_each_entry(q, &crypto_alg_list, cra_list) {
		if (alg == q) {
			list_del(&alg->cra_list);
			ret = 0;
			goto out;
		}
	}
out:	
	up_write(&crypto_alg_sem);
	return ret;
}

int crypto_alg_available(const char *name, u32 flags)
{
	int ret = 0;
	struct crypto_alg *alg = crypto_alg_mod_lookup(name);
	
	if (alg) {
		crypto_alg_put(alg);
		ret = 1;
	}
	
	return ret;
}

static int __init init_crypto(void)
{
	printk(KERN_INFO "Initializing Cryptographic API\n");
	crypto_init_proc();
	return 0;
}

__initcall(init_crypto);

EXPORT_SYMBOL_GPL(crypto_register_alg);
EXPORT_SYMBOL_GPL(crypto_unregister_alg);
EXPORT_SYMBOL_GPL(crypto_alloc_tfm);
EXPORT_SYMBOL_GPL(crypto_free_tfm);
EXPORT_SYMBOL_GPL(crypto_alg_available);