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TOMOYO Linux Cross Reference
Linux/crypto/seqiv.c

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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 
 27 struct seqiv_ctx {
 28         spinlock_t lock;
 29         u8 salt[] __attribute__ ((aligned(__alignof__(u32))));
 30 };
 31 
 32 static 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 
 46 out:
 47         kfree(subreq->info);
 48 }
 49 
 50 static 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 
 58 static 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 
 72 out:
 73         kfree(subreq->iv);
 74 }
 75 
 76 static 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 
 84 static 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 
 98 static 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 
143 static 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 
189 static 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 
203 unlock:
204         spin_unlock_bh(&ctx->lock);
205 
206         if (err)
207                 return err;
208 
209         return seqiv_givencrypt(req);
210 }
211 
212 static 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 
226 unlock:
227         spin_unlock_bh(&ctx->lock);
228 
229         if (err)
230                 return err;
231 
232         return seqiv_aead_givencrypt(req);
233 }
234 
235 static 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 
247 static 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 
259 static struct crypto_template seqiv_tmpl;
260 
261 static 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 
277 out:
278         return inst;
279 }
280 
281 static 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 
297 out:
298         return inst;
299 }
300 
301 static 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         if (IS_ERR(algt))
309                 return ERR_CAST(algt);
310 
311         err = crypto_get_default_rng();
312         if (err)
313                 return ERR_PTR(err);
314 
315         if ((algt->type ^ CRYPTO_ALG_TYPE_AEAD) & CRYPTO_ALG_TYPE_MASK)
316                 inst = seqiv_ablkcipher_alloc(tb);
317         else
318                 inst = seqiv_aead_alloc(tb);
319 
320         if (IS_ERR(inst))
321                 goto put_rng;
322 
323         inst->alg.cra_alignmask |= __alignof__(u32) - 1;
324         inst->alg.cra_ctxsize += sizeof(struct seqiv_ctx);
325 
326 out:
327         return inst;
328 
329 put_rng:
330         crypto_put_default_rng();
331         goto out;
332 }
333 
334 static void seqiv_free(struct crypto_instance *inst)
335 {
336         if ((inst->alg.cra_flags ^ CRYPTO_ALG_TYPE_AEAD) & CRYPTO_ALG_TYPE_MASK)
337                 skcipher_geniv_free(inst);
338         else
339                 aead_geniv_free(inst);
340         crypto_put_default_rng();
341 }
342 
343 static struct crypto_template seqiv_tmpl = {
344         .name = "seqiv",
345         .alloc = seqiv_alloc,
346         .free = seqiv_free,
347         .module = THIS_MODULE,
348 };
349 
350 static int __init seqiv_module_init(void)
351 {
352         return crypto_register_template(&seqiv_tmpl);
353 }
354 
355 static void __exit seqiv_module_exit(void)
356 {
357         crypto_unregister_template(&seqiv_tmpl);
358 }
359 
360 module_init(seqiv_module_init);
361 module_exit(seqiv_module_exit);
362 
363 MODULE_LICENSE("GPL");
364 MODULE_DESCRIPTION("Sequence Number IV Generator");
365 

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