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1/*
2 * seqiv: Sequence Number IV Generator
3 *
4 * This generator generates an IV based on a sequence number by xoring it
5 * with a salt. This algorithm is mainly useful for CTR and similar modes.
6 *
7 * Copyright (c) 2007 Herbert Xu <herbert@gondor.apana.org.au>
8 *
9 * This program is free software; you can redistribute it and/or modify it
10 * under the terms of the GNU General Public License as published by the Free
11 * Software Foundation; either version 2 of the License, or (at your option)
12 * any later version.
13 *
14 */
15
16#include <crypto/internal/aead.h>
17#include <crypto/internal/skcipher.h>
18#include <crypto/rng.h>
19#include <linux/err.h>
20#include <linux/init.h>
21#include <linux/kernel.h>
22#include <linux/module.h>
23#include <linux/slab.h>
24#include <linux/spinlock.h>
25#include <linux/string.h>
26
27struct seqiv_ctx {
28 spinlock_t lock;
29 u8 salt[] __attribute__ ((aligned(__alignof__(u32))));
30};
31
32static void seqiv_complete2(struct skcipher_givcrypt_request *req, int err)
33{
34 struct ablkcipher_request *subreq = skcipher_givcrypt_reqctx(req);
35 struct crypto_ablkcipher *geniv;
36
37 if (err == -EINPROGRESS)
38 return;
39
40 if (err)
41 goto out;
42
43 geniv = skcipher_givcrypt_reqtfm(req);
44 memcpy(req->creq.info, subreq->info, crypto_ablkcipher_ivsize(geniv));
45
46out:
47 kfree(subreq->info);
48}
49
50static void seqiv_complete(struct crypto_async_request *base, int err)
51{
52 struct skcipher_givcrypt_request *req = base->data;
53
54 seqiv_complete2(req, err);
55 skcipher_givcrypt_complete(req, err);
56}
57
58static void seqiv_aead_complete2(struct aead_givcrypt_request *req, int err)
59{
60 struct aead_request *subreq = aead_givcrypt_reqctx(req);
61 struct crypto_aead *geniv;
62
63 if (err == -EINPROGRESS)
64 return;
65
66 if (err)
67 goto out;
68
69 geniv = aead_givcrypt_reqtfm(req);
70 memcpy(req->areq.iv, subreq->iv, crypto_aead_ivsize(geniv));
71
72out:
73 kfree(subreq->iv);
74}
75
76static void seqiv_aead_complete(struct crypto_async_request *base, int err)
77{
78 struct aead_givcrypt_request *req = base->data;
79
80 seqiv_aead_complete2(req, err);
81 aead_givcrypt_complete(req, err);
82}
83
84static void seqiv_geniv(struct seqiv_ctx *ctx, u8 *info, u64 seq,
85 unsigned int ivsize)
86{
87 unsigned int len = ivsize;
88
89 if (ivsize > sizeof(u64)) {
90 memset(info, 0, ivsize - sizeof(u64));
91 len = sizeof(u64);
92 }
93 seq = cpu_to_be64(seq);
94 memcpy(info + ivsize - len, &seq, len);
95 crypto_xor(info, ctx->salt, ivsize);
96}
97
98static int seqiv_givencrypt(struct skcipher_givcrypt_request *req)
99{
100 struct crypto_ablkcipher *geniv = skcipher_givcrypt_reqtfm(req);
101 struct seqiv_ctx *ctx = crypto_ablkcipher_ctx(geniv);
102 struct ablkcipher_request *subreq = skcipher_givcrypt_reqctx(req);
103 crypto_completion_t complete;
104 void *data;
105 u8 *info;
106 unsigned int ivsize;
107 int err;
108
109 ablkcipher_request_set_tfm(subreq, skcipher_geniv_cipher(geniv));
110
111 complete = req->creq.base.complete;
112 data = req->creq.base.data;
113 info = req->creq.info;
114
115 ivsize = crypto_ablkcipher_ivsize(geniv);
116
117 if (unlikely(!IS_ALIGNED((unsigned long)info,
118 crypto_ablkcipher_alignmask(geniv) + 1))) {
119 info = kmalloc(ivsize, req->creq.base.flags &
120 CRYPTO_TFM_REQ_MAY_SLEEP ? GFP_KERNEL:
121 GFP_ATOMIC);
122 if (!info)
123 return -ENOMEM;
124
125 complete = seqiv_complete;
126 data = req;
127 }
128
129 ablkcipher_request_set_callback(subreq, req->creq.base.flags, complete,
130 data);
131 ablkcipher_request_set_crypt(subreq, req->creq.src, req->creq.dst,
132 req->creq.nbytes, info);
133
134 seqiv_geniv(ctx, info, req->seq, ivsize);
135 memcpy(req->giv, info, ivsize);
136
137 err = crypto_ablkcipher_encrypt(subreq);
138 if (unlikely(info != req->creq.info))
139 seqiv_complete2(req, err);
140 return err;
141}
142
143static int seqiv_aead_givencrypt(struct aead_givcrypt_request *req)
144{
145 struct crypto_aead *geniv = aead_givcrypt_reqtfm(req);
146 struct seqiv_ctx *ctx = crypto_aead_ctx(geniv);
147 struct aead_request *areq = &req->areq;
148 struct aead_request *subreq = aead_givcrypt_reqctx(req);
149 crypto_completion_t complete;
150 void *data;
151 u8 *info;
152 unsigned int ivsize;
153 int err;
154
155 aead_request_set_tfm(subreq, aead_geniv_base(geniv));
156
157 complete = areq->base.complete;
158 data = areq->base.data;
159 info = areq->iv;
160
161 ivsize = crypto_aead_ivsize(geniv);
162
163 if (unlikely(!IS_ALIGNED((unsigned long)info,
164 crypto_aead_alignmask(geniv) + 1))) {
165 info = kmalloc(ivsize, areq->base.flags &
166 CRYPTO_TFM_REQ_MAY_SLEEP ? GFP_KERNEL:
167 GFP_ATOMIC);
168 if (!info)
169 return -ENOMEM;
170
171 complete = seqiv_aead_complete;
172 data = req;
173 }
174
175 aead_request_set_callback(subreq, areq->base.flags, complete, data);
176 aead_request_set_crypt(subreq, areq->src, areq->dst, areq->cryptlen,
177 info);
178 aead_request_set_assoc(subreq, areq->assoc, areq->assoclen);
179
180 seqiv_geniv(ctx, info, req->seq, ivsize);
181 memcpy(req->giv, info, ivsize);
182
183 err = crypto_aead_encrypt(subreq);
184 if (unlikely(info != areq->iv))
185 seqiv_aead_complete2(req, err);
186 return err;
187}
188
189static int seqiv_givencrypt_first(struct skcipher_givcrypt_request *req)
190{
191 struct crypto_ablkcipher *geniv = skcipher_givcrypt_reqtfm(req);
192 struct seqiv_ctx *ctx = crypto_ablkcipher_ctx(geniv);
193 int err = 0;
194
195 spin_lock_bh(&ctx->lock);
196 if (crypto_ablkcipher_crt(geniv)->givencrypt != seqiv_givencrypt_first)
197 goto unlock;
198
199 crypto_ablkcipher_crt(geniv)->givencrypt = seqiv_givencrypt;
200 err = crypto_rng_get_bytes(crypto_default_rng, ctx->salt,
201 crypto_ablkcipher_ivsize(geniv));
202
203unlock:
204 spin_unlock_bh(&ctx->lock);
205
206 if (err)
207 return err;
208
209 return seqiv_givencrypt(req);
210}
211
212static int seqiv_aead_givencrypt_first(struct aead_givcrypt_request *req)
213{
214 struct crypto_aead *geniv = aead_givcrypt_reqtfm(req);
215 struct seqiv_ctx *ctx = crypto_aead_ctx(geniv);
216 int err = 0;
217
218 spin_lock_bh(&ctx->lock);
219 if (crypto_aead_crt(geniv)->givencrypt != seqiv_aead_givencrypt_first)
220 goto unlock;
221
222 crypto_aead_crt(geniv)->givencrypt = seqiv_aead_givencrypt;
223 err = crypto_rng_get_bytes(crypto_default_rng, ctx->salt,
224 crypto_aead_ivsize(geniv));
225
226unlock:
227 spin_unlock_bh(&ctx->lock);
228
229 if (err)
230 return err;
231
232 return seqiv_aead_givencrypt(req);
233}
234
235static int seqiv_init(struct crypto_tfm *tfm)
236{
237 struct crypto_ablkcipher *geniv = __crypto_ablkcipher_cast(tfm);
238 struct seqiv_ctx *ctx = crypto_ablkcipher_ctx(geniv);
239
240 spin_lock_init(&ctx->lock);
241
242 tfm->crt_ablkcipher.reqsize = sizeof(struct ablkcipher_request);
243
244 return skcipher_geniv_init(tfm);
245}
246
247static int seqiv_aead_init(struct crypto_tfm *tfm)
248{
249 struct crypto_aead *geniv = __crypto_aead_cast(tfm);
250 struct seqiv_ctx *ctx = crypto_aead_ctx(geniv);
251
252 spin_lock_init(&ctx->lock);
253
254 tfm->crt_aead.reqsize = sizeof(struct aead_request);
255
256 return aead_geniv_init(tfm);
257}
258
259static struct crypto_template seqiv_tmpl;
260
261static struct crypto_instance *seqiv_ablkcipher_alloc(struct rtattr **tb)
262{
263 struct crypto_instance *inst;
264
265 inst = skcipher_geniv_alloc(&seqiv_tmpl, tb, 0, 0);
266
267 if (IS_ERR(inst))
268 goto out;
269
270 inst->alg.cra_ablkcipher.givencrypt = seqiv_givencrypt_first;
271
272 inst->alg.cra_init = seqiv_init;
273 inst->alg.cra_exit = skcipher_geniv_exit;
274
275 inst->alg.cra_ctxsize += inst->alg.cra_ablkcipher.ivsize;
276
277out:
278 return inst;
279}
280
281static struct crypto_instance *seqiv_aead_alloc(struct rtattr **tb)
282{
283 struct crypto_instance *inst;
284
285 inst = aead_geniv_alloc(&seqiv_tmpl, tb, 0, 0);
286
287 if (IS_ERR(inst))
288 goto out;
289
290 inst->alg.cra_aead.givencrypt = seqiv_aead_givencrypt_first;
291
292 inst->alg.cra_init = seqiv_aead_init;
293 inst->alg.cra_exit = aead_geniv_exit;
294
295 inst->alg.cra_ctxsize = inst->alg.cra_aead.ivsize;
296
297out:
298 return inst;
299}
300
301static struct crypto_instance *seqiv_alloc(struct rtattr **tb)
302{
303 struct crypto_attr_type *algt;
304 struct crypto_instance *inst;
305 int err;
306
307 algt = crypto_get_attr_type(tb);
308 err = PTR_ERR(algt);
309 if (IS_ERR(algt))
310 return ERR_PTR(err);
311
312 err = crypto_get_default_rng();
313 if (err)
314 return ERR_PTR(err);
315
316 if ((algt->type ^ CRYPTO_ALG_TYPE_AEAD) & CRYPTO_ALG_TYPE_MASK)
317 inst = seqiv_ablkcipher_alloc(tb);
318 else
319 inst = seqiv_aead_alloc(tb);
320
321 if (IS_ERR(inst))
322 goto put_rng;
323
324 inst->alg.cra_alignmask |= __alignof__(u32) - 1;
325 inst->alg.cra_ctxsize += sizeof(struct seqiv_ctx);
326
327out:
328 return inst;
329
330put_rng:
331 crypto_put_default_rng();
332 goto out;
333}
334
335static void seqiv_free(struct crypto_instance *inst)
336{
337 if ((inst->alg.cra_flags ^ CRYPTO_ALG_TYPE_AEAD) & CRYPTO_ALG_TYPE_MASK)
338 skcipher_geniv_free(inst);
339 else
340 aead_geniv_free(inst);
341 crypto_put_default_rng();
342}
343
344static struct crypto_template seqiv_tmpl = {
345 .name = "seqiv",
346 .alloc = seqiv_alloc,
347 .free = seqiv_free,
348 .module = THIS_MODULE,
349};
350
351static int __init seqiv_module_init(void)
352{
353 return crypto_register_template(&seqiv_tmpl);
354}
355
356static void __exit seqiv_module_exit(void)
357{
358 crypto_unregister_template(&seqiv_tmpl);
359}
360
361module_init(seqiv_module_init);
362module_exit(seqiv_module_exit);
363
364MODULE_LICENSE("GPL");
365MODULE_DESCRIPTION("Sequence Number IV Generator");
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * seqiv: Sequence Number IV Generator
4 *
5 * This generator generates an IV based on a sequence number by xoring it
6 * with a salt. This algorithm is mainly useful for CTR and similar modes.
7 *
8 * Copyright (c) 2007 Herbert Xu <herbert@gondor.apana.org.au>
9 */
10
11#include <crypto/internal/geniv.h>
12#include <crypto/scatterwalk.h>
13#include <crypto/skcipher.h>
14#include <linux/err.h>
15#include <linux/init.h>
16#include <linux/kernel.h>
17#include <linux/module.h>
18#include <linux/slab.h>
19#include <linux/string.h>
20
21static void seqiv_aead_encrypt_complete2(struct aead_request *req, int err)
22{
23 struct aead_request *subreq = aead_request_ctx(req);
24 struct crypto_aead *geniv;
25
26 if (err == -EINPROGRESS)
27 return;
28
29 if (err)
30 goto out;
31
32 geniv = crypto_aead_reqtfm(req);
33 memcpy(req->iv, subreq->iv, crypto_aead_ivsize(geniv));
34
35out:
36 kfree_sensitive(subreq->iv);
37}
38
39static void seqiv_aead_encrypt_complete(struct crypto_async_request *base,
40 int err)
41{
42 struct aead_request *req = base->data;
43
44 seqiv_aead_encrypt_complete2(req, err);
45 aead_request_complete(req, err);
46}
47
48static int seqiv_aead_encrypt(struct aead_request *req)
49{
50 struct crypto_aead *geniv = crypto_aead_reqtfm(req);
51 struct aead_geniv_ctx *ctx = crypto_aead_ctx(geniv);
52 struct aead_request *subreq = aead_request_ctx(req);
53 crypto_completion_t compl;
54 void *data;
55 u8 *info;
56 unsigned int ivsize = 8;
57 int err;
58
59 if (req->cryptlen < ivsize)
60 return -EINVAL;
61
62 aead_request_set_tfm(subreq, ctx->child);
63
64 compl = req->base.complete;
65 data = req->base.data;
66 info = req->iv;
67
68 if (req->src != req->dst) {
69 SYNC_SKCIPHER_REQUEST_ON_STACK(nreq, ctx->sknull);
70
71 skcipher_request_set_sync_tfm(nreq, ctx->sknull);
72 skcipher_request_set_callback(nreq, req->base.flags,
73 NULL, NULL);
74 skcipher_request_set_crypt(nreq, req->src, req->dst,
75 req->assoclen + req->cryptlen,
76 NULL);
77
78 err = crypto_skcipher_encrypt(nreq);
79 if (err)
80 return err;
81 }
82
83 if (unlikely(!IS_ALIGNED((unsigned long)info,
84 crypto_aead_alignmask(geniv) + 1))) {
85 info = kmemdup(req->iv, ivsize, req->base.flags &
86 CRYPTO_TFM_REQ_MAY_SLEEP ? GFP_KERNEL :
87 GFP_ATOMIC);
88 if (!info)
89 return -ENOMEM;
90
91 compl = seqiv_aead_encrypt_complete;
92 data = req;
93 }
94
95 aead_request_set_callback(subreq, req->base.flags, compl, data);
96 aead_request_set_crypt(subreq, req->dst, req->dst,
97 req->cryptlen - ivsize, info);
98 aead_request_set_ad(subreq, req->assoclen + ivsize);
99
100 crypto_xor(info, ctx->salt, ivsize);
101 scatterwalk_map_and_copy(info, req->dst, req->assoclen, ivsize, 1);
102
103 err = crypto_aead_encrypt(subreq);
104 if (unlikely(info != req->iv))
105 seqiv_aead_encrypt_complete2(req, err);
106 return err;
107}
108
109static int seqiv_aead_decrypt(struct aead_request *req)
110{
111 struct crypto_aead *geniv = crypto_aead_reqtfm(req);
112 struct aead_geniv_ctx *ctx = crypto_aead_ctx(geniv);
113 struct aead_request *subreq = aead_request_ctx(req);
114 crypto_completion_t compl;
115 void *data;
116 unsigned int ivsize = 8;
117
118 if (req->cryptlen < ivsize + crypto_aead_authsize(geniv))
119 return -EINVAL;
120
121 aead_request_set_tfm(subreq, ctx->child);
122
123 compl = req->base.complete;
124 data = req->base.data;
125
126 aead_request_set_callback(subreq, req->base.flags, compl, data);
127 aead_request_set_crypt(subreq, req->src, req->dst,
128 req->cryptlen - ivsize, req->iv);
129 aead_request_set_ad(subreq, req->assoclen + ivsize);
130
131 scatterwalk_map_and_copy(req->iv, req->src, req->assoclen, ivsize, 0);
132
133 return crypto_aead_decrypt(subreq);
134}
135
136static int seqiv_aead_create(struct crypto_template *tmpl, struct rtattr **tb)
137{
138 struct aead_instance *inst;
139 int err;
140
141 inst = aead_geniv_alloc(tmpl, tb);
142
143 if (IS_ERR(inst))
144 return PTR_ERR(inst);
145
146 err = -EINVAL;
147 if (inst->alg.ivsize != sizeof(u64))
148 goto free_inst;
149
150 inst->alg.encrypt = seqiv_aead_encrypt;
151 inst->alg.decrypt = seqiv_aead_decrypt;
152
153 inst->alg.init = aead_init_geniv;
154 inst->alg.exit = aead_exit_geniv;
155
156 inst->alg.base.cra_ctxsize = sizeof(struct aead_geniv_ctx);
157 inst->alg.base.cra_ctxsize += inst->alg.ivsize;
158
159 err = aead_register_instance(tmpl, inst);
160 if (err) {
161free_inst:
162 inst->free(inst);
163 }
164 return err;
165}
166
167static struct crypto_template seqiv_tmpl = {
168 .name = "seqiv",
169 .create = seqiv_aead_create,
170 .module = THIS_MODULE,
171};
172
173static int __init seqiv_module_init(void)
174{
175 return crypto_register_template(&seqiv_tmpl);
176}
177
178static void __exit seqiv_module_exit(void)
179{
180 crypto_unregister_template(&seqiv_tmpl);
181}
182
183subsys_initcall(seqiv_module_init);
184module_exit(seqiv_module_exit);
185
186MODULE_LICENSE("GPL");
187MODULE_DESCRIPTION("Sequence Number IV Generator");
188MODULE_ALIAS_CRYPTO("seqiv");