aboutsummaryrefslogtreecommitdiff
path: root/crypto/seqiv.c
blob: 15a749a5cab72ea53d597cfa1983a2a175154cc2 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
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
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
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
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
/*
 * seqiv: Sequence Number IV Generator
 *
 * This generator generates an IV based on a sequence number by xoring it
 * with a salt.  This algorithm is mainly useful for CTR and similar modes.
 *
 * Copyright (c) 2007 Herbert Xu <herbert@gondor.apana.org.au>
 *
 * 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.
 *
 */

#include <crypto/internal/geniv.h>
#include <crypto/internal/skcipher.h>
#include <crypto/rng.h>
#include <crypto/scatterwalk.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/string.h>

struct seqiv_ctx {
	spinlock_t lock;
	u8 salt[] __attribute__ ((aligned(__alignof__(u32))));
};

static void seqiv_free(struct crypto_instance *inst);

static void seqiv_complete2(struct skcipher_givcrypt_request *req, int err)
{
	struct ablkcipher_request *subreq = skcipher_givcrypt_reqctx(req);
	struct crypto_ablkcipher *geniv;

	if (err == -EINPROGRESS)
		return;

	if (err)
		goto out;

	geniv = skcipher_givcrypt_reqtfm(req);
	memcpy(req->creq.info, subreq->info, crypto_ablkcipher_ivsize(geniv));

out:
	kfree(subreq->info);
}

static void seqiv_complete(struct crypto_async_request *base, int err)
{
	struct skcipher_givcrypt_request *req = base->data;

	seqiv_complete2(req, err);
	skcipher_givcrypt_complete(req, err);
}

static void seqiv_aead_encrypt_complete2(struct aead_request *req, int err)
{
	struct aead_request *subreq = aead_request_ctx(req);
	struct crypto_aead *geniv;

	if (err == -EINPROGRESS)
		return;

	if (err)
		goto out;

	geniv = crypto_aead_reqtfm(req);
	memcpy(req->iv, subreq->iv, crypto_aead_ivsize(geniv));

out:
	kzfree(subreq->iv);
}

static void seqiv_aead_encrypt_complete(struct crypto_async_request *base,
					int err)
{
	struct aead_request *req = base->data;

	seqiv_aead_encrypt_complete2(req, err);
	aead_request_complete(req, err);
}

static void seqiv_geniv(struct seqiv_ctx *ctx, u8 *info, u64 seq,
			unsigned int ivsize)
{
	unsigned int len = ivsize;

	if (ivsize > sizeof(u64)) {
		memset(info, 0, ivsize - sizeof(u64));
		len = sizeof(u64);
	}
	seq = cpu_to_be64(seq);
	memcpy(info + ivsize - len, &seq, len);
	crypto_xor(info, ctx->salt, ivsize);
}

static int seqiv_givencrypt(struct skcipher_givcrypt_request *req)
{
	struct crypto_ablkcipher *geniv = skcipher_givcrypt_reqtfm(req);
	struct seqiv_ctx *ctx = crypto_ablkcipher_ctx(geniv);
	struct ablkcipher_request *subreq = skcipher_givcrypt_reqctx(req);
	crypto_completion_t compl;
	void *data;
	u8 *info;
	unsigned int ivsize;
	int err;

	ablkcipher_request_set_tfm(subreq, skcipher_geniv_cipher(geniv));

	compl = req->creq.base.complete;
	data = req->creq.base.data;
	info = req->creq.info;

	ivsize = crypto_ablkcipher_ivsize(geniv);

	if (unlikely(!IS_ALIGNED((unsigned long)info,
				 crypto_ablkcipher_alignmask(geniv) + 1))) {
		info = kmalloc(ivsize, req->creq.base.flags &
				       CRYPTO_TFM_REQ_MAY_SLEEP ? GFP_KERNEL:
								  GFP_ATOMIC);
		if (!info)
			return -ENOMEM;

		compl = seqiv_complete;
		data = req;
	}

	ablkcipher_request_set_callback(subreq, req->creq.base.flags, compl,
					data);
	ablkcipher_request_set_crypt(subreq, req->creq.src, req->creq.dst,
				     req->creq.nbytes, info);

	seqiv_geniv(ctx, info, req->seq, ivsize);
	memcpy(req->giv, info, ivsize);

	err = crypto_ablkcipher_encrypt(subreq);
	if (unlikely(info != req->creq.info))
		seqiv_complete2(req, err);
	return err;
}

static int seqiv_aead_encrypt(struct aead_request *req)
{
	struct crypto_aead *geniv = crypto_aead_reqtfm(req);
	struct aead_geniv_ctx *ctx = crypto_aead_ctx(geniv);
	struct aead_request *subreq = aead_request_ctx(req);
	crypto_completion_t compl;
	void *data;
	u8 *info;
	unsigned int ivsize = 8;
	int err;

	if (req->cryptlen < ivsize)
		return -EINVAL;

	aead_request_set_tfm(subreq, ctx->child);

	compl = req->base.complete;
	data = req->base.data;
	info = req->iv;

	if (req->src != req->dst) {
		struct blkcipher_desc desc = {
			.tfm = ctx->null,
		};

		err = crypto_blkcipher_encrypt(&desc, req->dst, req->src,
					       req->assoclen + req->cryptlen);
		if (err)
			return err;
	}

	if (unlikely(!IS_ALIGNED((unsigned long)info,
				 crypto_aead_alignmask(geniv) + 1))) {
		info = kmalloc(ivsize, req->base.flags &
				       CRYPTO_TFM_REQ_MAY_SLEEP ? GFP_KERNEL:
								  GFP_ATOMIC);
		if (!info)
			return -ENOMEM;

		memcpy(info, req->iv, ivsize);
		compl = seqiv_aead_encrypt_complete;
		data = req;
	}

	aead_request_set_callback(subreq, req->base.flags, compl, data);
	aead_request_set_crypt(subreq, req->dst, req->dst,
			       req->cryptlen - ivsize, info);
	aead_request_set_ad(subreq, req->assoclen + ivsize);

	crypto_xor(info, ctx->salt, ivsize);
	scatterwalk_map_and_copy(info, req->dst, req->assoclen, ivsize, 1);

	err = crypto_aead_encrypt(subreq);
	if (unlikely(info != req->iv))
		seqiv_aead_encrypt_complete2(req, err);
	return err;
}

static int seqiv_aead_decrypt(struct aead_request *req)
{
	struct crypto_aead *geniv = crypto_aead_reqtfm(req);
	struct aead_geniv_ctx *ctx = crypto_aead_ctx(geniv);
	struct aead_request *subreq = aead_request_ctx(req);
	crypto_completion_t compl;
	void *data;
	unsigned int ivsize = 8;

	if (req->cryptlen < ivsize + crypto_aead_authsize(geniv))
		return -EINVAL;

	aead_request_set_tfm(subreq, ctx->child);

	compl = req->base.complete;
	data = req->base.data;

	aead_request_set_callback(subreq, req->base.flags, compl, data);
	aead_request_set_crypt(subreq, req->src, req->dst,
			       req->cryptlen - ivsize, req->iv);
	aead_request_set_ad(subreq, req->assoclen + ivsize);

	scatterwalk_map_and_copy(req->iv, req->src, req->assoclen, ivsize, 0);

	return crypto_aead_decrypt(subreq);
}

static int seqiv_init(struct crypto_tfm *tfm)
{
	struct crypto_ablkcipher *geniv = __crypto_ablkcipher_cast(tfm);
	struct seqiv_ctx *ctx = crypto_ablkcipher_ctx(geniv);
	int err;

	spin_lock_init(&ctx->lock);

	tfm->crt_ablkcipher.reqsize = sizeof(struct ablkcipher_request);

	err = 0;
	if (!crypto_get_default_rng()) {
		crypto_ablkcipher_crt(geniv)->givencrypt = seqiv_givencrypt;
		err = crypto_rng_get_bytes(crypto_default_rng, ctx->salt,
					   crypto_ablkcipher_ivsize(geniv));
		crypto_put_default_rng();
	}

	return err ?: skcipher_geniv_init(tfm);
}

static int seqiv_ablkcipher_create(struct crypto_template *tmpl,
				   struct rtattr **tb)
{
	struct crypto_instance *inst;
	int err;

	inst = skcipher_geniv_alloc(tmpl, tb, 0, 0);

	if (IS_ERR(inst))
		return PTR_ERR(inst);

	err = -EINVAL;
	if (inst->alg.cra_ablkcipher.ivsize < sizeof(u64))
		goto free_inst;

	inst->alg.cra_init = seqiv_init;
	inst->alg.cra_exit = skcipher_geniv_exit;

	inst->alg.cra_ctxsize += inst->alg.cra_ablkcipher.ivsize;
	inst->alg.cra_ctxsize += sizeof(struct seqiv_ctx);

	inst->alg.cra_alignmask |= __alignof__(u32) - 1;

	err = crypto_register_instance(tmpl, inst);
	if (err)
		goto free_inst;

out:
	return err;

free_inst:
	skcipher_geniv_free(inst);
	goto out;
}

static int seqiv_aead_create(struct crypto_template *tmpl, struct rtattr **tb)
{
	struct aead_instance *inst;
	struct crypto_aead_spawn *spawn;
	struct aead_alg *alg;
	int err;

	inst = aead_geniv_alloc(tmpl, tb, 0, 0);

	if (IS_ERR(inst))
		return PTR_ERR(inst);

	inst->alg.base.cra_alignmask |= __alignof__(u32) - 1;

	spawn = aead_instance_ctx(inst);
	alg = crypto_spawn_aead_alg(spawn);

	err = -EINVAL;
	if (inst->alg.ivsize != sizeof(u64))
		goto free_inst;

	inst->alg.encrypt = seqiv_aead_encrypt;
	inst->alg.decrypt = seqiv_aead_decrypt;

	inst->alg.init = aead_init_geniv;
	inst->alg.exit = aead_exit_geniv;

	inst->alg.base.cra_ctxsize = sizeof(struct aead_geniv_ctx);
	inst->alg.base.cra_ctxsize += inst->alg.ivsize;

	err = aead_register_instance(tmpl, inst);
	if (err)
		goto free_inst;

out:
	return err;

free_inst:
	aead_geniv_free(inst);
	goto out;
}

static int seqiv_create(struct crypto_template *tmpl, struct rtattr **tb)
{
	struct crypto_attr_type *algt;
	int err;

	algt = crypto_get_attr_type(tb);
	if (IS_ERR(algt))
		return PTR_ERR(algt);

	if ((algt->type ^ CRYPTO_ALG_TYPE_AEAD) & CRYPTO_ALG_TYPE_MASK)
		err = seqiv_ablkcipher_create(tmpl, tb);
	else
		err = seqiv_aead_create(tmpl, tb);

	return err;
}

static void seqiv_free(struct crypto_instance *inst)
{
	if ((inst->alg.cra_flags ^ CRYPTO_ALG_TYPE_AEAD) & CRYPTO_ALG_TYPE_MASK)
		skcipher_geniv_free(inst);
	else
		aead_geniv_free(aead_instance(inst));
}

static struct crypto_template seqiv_tmpl = {
	.name = "seqiv",
	.create = seqiv_create,
	.free = seqiv_free,
	.module = THIS_MODULE,
};

static int __init seqiv_module_init(void)
{
	return crypto_register_template(&seqiv_tmpl);
}

static void __exit seqiv_module_exit(void)
{
	crypto_unregister_template(&seqiv_tmpl);
}

module_init(seqiv_module_init);
module_exit(seqiv_module_exit);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Sequence Number IV Generator");
MODULE_ALIAS_CRYPTO("seqiv");