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