2 * seqiv: Sequence Number IV Generator
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.
7 * Copyright (c) 2007 Herbert Xu <herbert@gondor.apana.org.au>
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)
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>
29 u8 salt[] __attribute__ ((aligned(__alignof__(u32))));
32 static void seqiv_complete2(struct skcipher_givcrypt_request *req, int err)
34 struct ablkcipher_request *subreq = skcipher_givcrypt_reqctx(req);
35 struct crypto_ablkcipher *geniv;
37 if (err == -EINPROGRESS)
43 geniv = skcipher_givcrypt_reqtfm(req);
44 memcpy(req->creq.info, subreq->info, crypto_ablkcipher_ivsize(geniv));
50 static void seqiv_complete(struct crypto_async_request *base, int err)
52 struct skcipher_givcrypt_request *req = base->data;
54 seqiv_complete2(req, err);
55 skcipher_givcrypt_complete(req, err);
58 static void seqiv_aead_complete2(struct aead_givcrypt_request *req, int err)
60 struct aead_request *subreq = aead_givcrypt_reqctx(req);
61 struct crypto_aead *geniv;
63 if (err == -EINPROGRESS)
69 geniv = aead_givcrypt_reqtfm(req);
70 memcpy(req->areq.iv, subreq->iv, crypto_aead_ivsize(geniv));
76 static void seqiv_aead_complete(struct crypto_async_request *base, int err)
78 struct aead_givcrypt_request *req = base->data;
80 seqiv_aead_complete2(req, err);
81 aead_givcrypt_complete(req, err);
84 static void seqiv_geniv(struct seqiv_ctx *ctx, u8 *info, u64 seq,
87 unsigned int len = ivsize;
89 if (ivsize > sizeof(u64)) {
90 memset(info, 0, ivsize - sizeof(u64));
93 seq = cpu_to_be64(seq);
94 memcpy(info + ivsize - len, &seq, len);
95 crypto_xor(info, ctx->salt, ivsize);
98 static int seqiv_givencrypt(struct skcipher_givcrypt_request *req)
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;
109 ablkcipher_request_set_tfm(subreq, skcipher_geniv_cipher(geniv));
111 complete = req->creq.base.complete;
112 data = req->creq.base.data;
113 info = req->creq.info;
115 ivsize = crypto_ablkcipher_ivsize(geniv);
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:
125 complete = seqiv_complete;
129 ablkcipher_request_set_callback(subreq, req->creq.base.flags, complete,
131 ablkcipher_request_set_crypt(subreq, req->creq.src, req->creq.dst,
132 req->creq.nbytes, info);
134 seqiv_geniv(ctx, info, req->seq, ivsize);
135 memcpy(req->giv, info, ivsize);
137 err = crypto_ablkcipher_encrypt(subreq);
138 if (unlikely(info != req->creq.info))
139 seqiv_complete2(req, err);
143 static int seqiv_aead_givencrypt(struct aead_givcrypt_request *req)
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;
155 aead_request_set_tfm(subreq, aead_geniv_base(geniv));
157 complete = areq->base.complete;
158 data = areq->base.data;
161 ivsize = crypto_aead_ivsize(geniv);
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:
171 complete = seqiv_aead_complete;
175 aead_request_set_callback(subreq, areq->base.flags, complete, data);
176 aead_request_set_crypt(subreq, areq->src, areq->dst, areq->cryptlen,
178 aead_request_set_assoc(subreq, areq->assoc, areq->assoclen);
180 seqiv_geniv(ctx, info, req->seq, ivsize);
181 memcpy(req->giv, info, ivsize);
183 err = crypto_aead_encrypt(subreq);
184 if (unlikely(info != areq->iv))
185 seqiv_aead_complete2(req, err);
189 static int seqiv_givencrypt_first(struct skcipher_givcrypt_request *req)
191 struct crypto_ablkcipher *geniv = skcipher_givcrypt_reqtfm(req);
192 struct seqiv_ctx *ctx = crypto_ablkcipher_ctx(geniv);
195 spin_lock_bh(&ctx->lock);
196 if (crypto_ablkcipher_crt(geniv)->givencrypt != seqiv_givencrypt_first)
199 crypto_ablkcipher_crt(geniv)->givencrypt = seqiv_givencrypt;
200 err = crypto_rng_get_bytes(crypto_default_rng, ctx->salt,
201 crypto_ablkcipher_ivsize(geniv));
204 spin_unlock_bh(&ctx->lock);
209 return seqiv_givencrypt(req);
212 static int seqiv_aead_givencrypt_first(struct aead_givcrypt_request *req)
214 struct crypto_aead *geniv = aead_givcrypt_reqtfm(req);
215 struct seqiv_ctx *ctx = crypto_aead_ctx(geniv);
218 spin_lock_bh(&ctx->lock);
219 if (crypto_aead_crt(geniv)->givencrypt != seqiv_aead_givencrypt_first)
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));
227 spin_unlock_bh(&ctx->lock);
232 return seqiv_aead_givencrypt(req);
235 static int seqiv_init(struct crypto_tfm *tfm)
237 struct crypto_ablkcipher *geniv = __crypto_ablkcipher_cast(tfm);
238 struct seqiv_ctx *ctx = crypto_ablkcipher_ctx(geniv);
240 spin_lock_init(&ctx->lock);
242 tfm->crt_ablkcipher.reqsize = sizeof(struct ablkcipher_request);
244 return skcipher_geniv_init(tfm);
247 static int seqiv_aead_init(struct crypto_tfm *tfm)
249 struct crypto_aead *geniv = __crypto_aead_cast(tfm);
250 struct seqiv_ctx *ctx = crypto_aead_ctx(geniv);
252 spin_lock_init(&ctx->lock);
254 tfm->crt_aead.reqsize = sizeof(struct aead_request);
256 return aead_geniv_init(tfm);
259 static struct crypto_template seqiv_tmpl;
261 static struct crypto_instance *seqiv_ablkcipher_alloc(struct rtattr **tb)
263 struct crypto_instance *inst;
265 inst = skcipher_geniv_alloc(&seqiv_tmpl, tb, 0, 0);
270 inst->alg.cra_ablkcipher.givencrypt = seqiv_givencrypt_first;
272 inst->alg.cra_init = seqiv_init;
273 inst->alg.cra_exit = skcipher_geniv_exit;
275 inst->alg.cra_ctxsize += inst->alg.cra_ablkcipher.ivsize;
281 static struct crypto_instance *seqiv_aead_alloc(struct rtattr **tb)
283 struct crypto_instance *inst;
285 inst = aead_geniv_alloc(&seqiv_tmpl, tb, 0, 0);
290 inst->alg.cra_aead.givencrypt = seqiv_aead_givencrypt_first;
292 inst->alg.cra_init = seqiv_aead_init;
293 inst->alg.cra_exit = aead_geniv_exit;
295 inst->alg.cra_ctxsize = inst->alg.cra_aead.ivsize;
301 static struct crypto_instance *seqiv_alloc(struct rtattr **tb)
303 struct crypto_attr_type *algt;
304 struct crypto_instance *inst;
307 algt = crypto_get_attr_type(tb);
309 return ERR_CAST(algt);
311 err = crypto_get_default_rng();
315 if ((algt->type ^ CRYPTO_ALG_TYPE_AEAD) & CRYPTO_ALG_TYPE_MASK)
316 inst = seqiv_ablkcipher_alloc(tb);
318 inst = seqiv_aead_alloc(tb);
323 inst->alg.cra_alignmask |= __alignof__(u32) - 1;
324 inst->alg.cra_ctxsize += sizeof(struct seqiv_ctx);
330 crypto_put_default_rng();
334 static void seqiv_free(struct crypto_instance *inst)
336 if ((inst->alg.cra_flags ^ CRYPTO_ALG_TYPE_AEAD) & CRYPTO_ALG_TYPE_MASK)
337 skcipher_geniv_free(inst);
339 aead_geniv_free(inst);
340 crypto_put_default_rng();
343 static struct crypto_template seqiv_tmpl = {
345 .alloc = seqiv_alloc,
347 .module = THIS_MODULE,
350 static int __init seqiv_module_init(void)
352 return crypto_register_template(&seqiv_tmpl);
355 static void __exit seqiv_module_exit(void)
357 crypto_unregister_template(&seqiv_tmpl);
360 module_init(seqiv_module_init);
361 module_exit(seqiv_module_exit);
363 MODULE_LICENSE("GPL");
364 MODULE_DESCRIPTION("Sequence Number IV Generator");