Version:  2.0.40 2.2.26 2.4.37 3.13 3.14 3.15 3.16 3.17 3.18 3.19 4.0 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 4.9 4.10

Linux/crypto/pcbc.c

  1 /*
  2  * PCBC: Propagating Cipher Block Chaining mode
  3  *
  4  * Copyright (C) 2006 Red Hat, Inc. All Rights Reserved.
  5  * Written by David Howells (dhowells@redhat.com)
  6  *
  7  * Derived from cbc.c
  8  * - Copyright (c) 2006 Herbert Xu <herbert@gondor.apana.org.au>
  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 <crypto/internal/skcipher.h>
 18 #include <linux/err.h>
 19 #include <linux/init.h>
 20 #include <linux/kernel.h>
 21 #include <linux/module.h>
 22 #include <linux/slab.h>
 23 
 24 struct crypto_pcbc_ctx {
 25         struct crypto_cipher *child;
 26 };
 27 
 28 static int crypto_pcbc_setkey(struct crypto_skcipher *parent, const u8 *key,
 29                               unsigned int keylen)
 30 {
 31         struct crypto_pcbc_ctx *ctx = crypto_skcipher_ctx(parent);
 32         struct crypto_cipher *child = ctx->child;
 33         int err;
 34 
 35         crypto_cipher_clear_flags(child, CRYPTO_TFM_REQ_MASK);
 36         crypto_cipher_set_flags(child, crypto_skcipher_get_flags(parent) &
 37                                        CRYPTO_TFM_REQ_MASK);
 38         err = crypto_cipher_setkey(child, key, keylen);
 39         crypto_skcipher_set_flags(parent, crypto_cipher_get_flags(child) &
 40                                           CRYPTO_TFM_RES_MASK);
 41         return err;
 42 }
 43 
 44 static int crypto_pcbc_encrypt_segment(struct skcipher_request *req,
 45                                        struct skcipher_walk *walk,
 46                                        struct crypto_cipher *tfm)
 47 {
 48         int bsize = crypto_cipher_blocksize(tfm);
 49         unsigned int nbytes = walk->nbytes;
 50         u8 *src = walk->src.virt.addr;
 51         u8 *dst = walk->dst.virt.addr;
 52         u8 *iv = walk->iv;
 53 
 54         do {
 55                 crypto_xor(iv, src, bsize);
 56                 crypto_cipher_encrypt_one(tfm, dst, iv);
 57                 memcpy(iv, dst, bsize);
 58                 crypto_xor(iv, src, bsize);
 59 
 60                 src += bsize;
 61                 dst += bsize;
 62         } while ((nbytes -= bsize) >= bsize);
 63 
 64         return nbytes;
 65 }
 66 
 67 static int crypto_pcbc_encrypt_inplace(struct skcipher_request *req,
 68                                        struct skcipher_walk *walk,
 69                                        struct crypto_cipher *tfm)
 70 {
 71         int bsize = crypto_cipher_blocksize(tfm);
 72         unsigned int nbytes = walk->nbytes;
 73         u8 *src = walk->src.virt.addr;
 74         u8 *iv = walk->iv;
 75         u8 tmpbuf[bsize];
 76 
 77         do {
 78                 memcpy(tmpbuf, src, bsize);
 79                 crypto_xor(iv, src, bsize);
 80                 crypto_cipher_encrypt_one(tfm, src, iv);
 81                 memcpy(iv, tmpbuf, bsize);
 82                 crypto_xor(iv, src, bsize);
 83 
 84                 src += bsize;
 85         } while ((nbytes -= bsize) >= bsize);
 86 
 87         memcpy(walk->iv, iv, bsize);
 88 
 89         return nbytes;
 90 }
 91 
 92 static int crypto_pcbc_encrypt(struct skcipher_request *req)
 93 {
 94         struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
 95         struct crypto_pcbc_ctx *ctx = crypto_skcipher_ctx(tfm);
 96         struct crypto_cipher *child = ctx->child;
 97         struct skcipher_walk walk;
 98         unsigned int nbytes;
 99         int err;
100 
101         err = skcipher_walk_virt(&walk, req, false);
102 
103         while ((nbytes = walk.nbytes)) {
104                 if (walk.src.virt.addr == walk.dst.virt.addr)
105                         nbytes = crypto_pcbc_encrypt_inplace(req, &walk,
106                                                              child);
107                 else
108                         nbytes = crypto_pcbc_encrypt_segment(req, &walk,
109                                                              child);
110                 err = skcipher_walk_done(&walk, nbytes);
111         }
112 
113         return err;
114 }
115 
116 static int crypto_pcbc_decrypt_segment(struct skcipher_request *req,
117                                        struct skcipher_walk *walk,
118                                        struct crypto_cipher *tfm)
119 {
120         int bsize = crypto_cipher_blocksize(tfm);
121         unsigned int nbytes = walk->nbytes;
122         u8 *src = walk->src.virt.addr;
123         u8 *dst = walk->dst.virt.addr;
124         u8 *iv = walk->iv;
125 
126         do {
127                 crypto_cipher_decrypt_one(tfm, dst, src);
128                 crypto_xor(dst, iv, bsize);
129                 memcpy(iv, src, bsize);
130                 crypto_xor(iv, dst, bsize);
131 
132                 src += bsize;
133                 dst += bsize;
134         } while ((nbytes -= bsize) >= bsize);
135 
136         memcpy(walk->iv, iv, bsize);
137 
138         return nbytes;
139 }
140 
141 static int crypto_pcbc_decrypt_inplace(struct skcipher_request *req,
142                                        struct skcipher_walk *walk,
143                                        struct crypto_cipher *tfm)
144 {
145         int bsize = crypto_cipher_blocksize(tfm);
146         unsigned int nbytes = walk->nbytes;
147         u8 *src = walk->src.virt.addr;
148         u8 *iv = walk->iv;
149         u8 tmpbuf[bsize] __attribute__ ((aligned(__alignof__(u32))));
150 
151         do {
152                 memcpy(tmpbuf, src, bsize);
153                 crypto_cipher_decrypt_one(tfm, src, src);
154                 crypto_xor(src, iv, bsize);
155                 memcpy(iv, tmpbuf, bsize);
156                 crypto_xor(iv, src, bsize);
157 
158                 src += bsize;
159         } while ((nbytes -= bsize) >= bsize);
160 
161         memcpy(walk->iv, iv, bsize);
162 
163         return nbytes;
164 }
165 
166 static int crypto_pcbc_decrypt(struct skcipher_request *req)
167 {
168         struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
169         struct crypto_pcbc_ctx *ctx = crypto_skcipher_ctx(tfm);
170         struct crypto_cipher *child = ctx->child;
171         struct skcipher_walk walk;
172         unsigned int nbytes;
173         int err;
174 
175         err = skcipher_walk_virt(&walk, req, false);
176 
177         while ((nbytes = walk.nbytes)) {
178                 if (walk.src.virt.addr == walk.dst.virt.addr)
179                         nbytes = crypto_pcbc_decrypt_inplace(req, &walk,
180                                                              child);
181                 else
182                         nbytes = crypto_pcbc_decrypt_segment(req, &walk,
183                                                              child);
184                 err = skcipher_walk_done(&walk, nbytes);
185         }
186 
187         return err;
188 }
189 
190 static int crypto_pcbc_init_tfm(struct crypto_skcipher *tfm)
191 {
192         struct skcipher_instance *inst = skcipher_alg_instance(tfm);
193         struct crypto_spawn *spawn = skcipher_instance_ctx(inst);
194         struct crypto_pcbc_ctx *ctx = crypto_skcipher_ctx(tfm);
195         struct crypto_cipher *cipher;
196 
197         cipher = crypto_spawn_cipher(spawn);
198         if (IS_ERR(cipher))
199                 return PTR_ERR(cipher);
200 
201         ctx->child = cipher;
202         return 0;
203 }
204 
205 static void crypto_pcbc_exit_tfm(struct crypto_skcipher *tfm)
206 {
207         struct crypto_pcbc_ctx *ctx = crypto_skcipher_ctx(tfm);
208 
209         crypto_free_cipher(ctx->child);
210 }
211 
212 static void crypto_pcbc_free(struct skcipher_instance *inst)
213 {
214         crypto_drop_skcipher(skcipher_instance_ctx(inst));
215         kfree(inst);
216 }
217 
218 static int crypto_pcbc_create(struct crypto_template *tmpl, struct rtattr **tb)
219 {
220         struct skcipher_instance *inst;
221         struct crypto_attr_type *algt;
222         struct crypto_spawn *spawn;
223         struct crypto_alg *alg;
224         int err;
225 
226         algt = crypto_get_attr_type(tb);
227         if (IS_ERR(algt))
228                 return PTR_ERR(algt);
229 
230         if (((algt->type ^ CRYPTO_ALG_TYPE_SKCIPHER) & algt->mask) &
231             ~CRYPTO_ALG_INTERNAL)
232                 return -EINVAL;
233 
234         inst = kzalloc(sizeof(*inst) + sizeof(*spawn), GFP_KERNEL);
235         if (!inst)
236                 return -ENOMEM;
237 
238         alg = crypto_get_attr_alg(tb, CRYPTO_ALG_TYPE_CIPHER |
239                                       (algt->type & CRYPTO_ALG_INTERNAL),
240                                   CRYPTO_ALG_TYPE_MASK |
241                                   (algt->mask & CRYPTO_ALG_INTERNAL));
242         err = PTR_ERR(alg);
243         if (IS_ERR(alg))
244                 goto err_free_inst;
245 
246         spawn = skcipher_instance_ctx(inst);
247         err = crypto_init_spawn(spawn, alg, skcipher_crypto_instance(inst),
248                                 CRYPTO_ALG_TYPE_MASK);
249         crypto_mod_put(alg);
250         if (err)
251                 goto err_free_inst;
252 
253         err = crypto_inst_setname(skcipher_crypto_instance(inst), "pcbc", alg);
254         if (err)
255                 goto err_drop_spawn;
256 
257         inst->alg.base.cra_flags = alg->cra_flags & CRYPTO_ALG_INTERNAL;
258         inst->alg.base.cra_priority = alg->cra_priority;
259         inst->alg.base.cra_blocksize = alg->cra_blocksize;
260         inst->alg.base.cra_alignmask = alg->cra_alignmask;
261 
262         /* We access the data as u32s when xoring. */
263         inst->alg.base.cra_alignmask |= __alignof__(u32) - 1;
264 
265         inst->alg.ivsize = alg->cra_blocksize;
266         inst->alg.min_keysize = alg->cra_cipher.cia_min_keysize;
267         inst->alg.max_keysize = alg->cra_cipher.cia_max_keysize;
268 
269         inst->alg.base.cra_ctxsize = sizeof(struct crypto_pcbc_ctx);
270 
271         inst->alg.init = crypto_pcbc_init_tfm;
272         inst->alg.exit = crypto_pcbc_exit_tfm;
273 
274         inst->alg.setkey = crypto_pcbc_setkey;
275         inst->alg.encrypt = crypto_pcbc_encrypt;
276         inst->alg.decrypt = crypto_pcbc_decrypt;
277 
278         inst->free = crypto_pcbc_free;
279 
280         err = skcipher_register_instance(tmpl, inst);
281         if (err)
282                 goto err_drop_spawn;
283 
284 out:
285         return err;
286 
287 err_drop_spawn:
288         crypto_drop_spawn(spawn);
289 err_free_inst:
290         kfree(inst);
291         goto out;
292 }
293 
294 static struct crypto_template crypto_pcbc_tmpl = {
295         .name = "pcbc",
296         .create = crypto_pcbc_create,
297         .module = THIS_MODULE,
298 };
299 
300 static int __init crypto_pcbc_module_init(void)
301 {
302         return crypto_register_template(&crypto_pcbc_tmpl);
303 }
304 
305 static void __exit crypto_pcbc_module_exit(void)
306 {
307         crypto_unregister_template(&crypto_pcbc_tmpl);
308 }
309 
310 module_init(crypto_pcbc_module_init);
311 module_exit(crypto_pcbc_module_exit);
312 
313 MODULE_LICENSE("GPL");
314 MODULE_DESCRIPTION("PCBC block cipher algorithm");
315 MODULE_ALIAS_CRYPTO("pcbc");
316 

This page was automatically generated by LXR 0.3.1 (source).  •  Linux is a registered trademark of Linus Torvalds  •  Contact us