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Herbert Xu0a270322007-11-30 21:38:37 +11001/*
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
Herbert Xu661cfd02015-05-27 14:37:37 +080016#include <crypto/internal/geniv.h>
Herbert Xu856e3f402015-05-21 15:11:13 +080017#include <crypto/scatterwalk.h>
Herbert Xu3a01d0e2016-07-12 13:17:50 +080018#include <crypto/skcipher.h>
Herbert Xu0a270322007-11-30 21:38:37 +110019#include <linux/err.h>
20#include <linux/init.h>
21#include <linux/kernel.h>
22#include <linux/module.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090023#include <linux/slab.h>
Herbert Xu0a270322007-11-30 21:38:37 +110024#include <linux/string.h>
25
Herbert Xu06771572015-05-23 15:41:51 +080026static void seqiv_free(struct crypto_instance *inst);
27
Herbert Xu856e3f402015-05-21 15:11:13 +080028static void seqiv_aead_encrypt_complete2(struct aead_request *req, int err)
29{
30 struct aead_request *subreq = aead_request_ctx(req);
31 struct crypto_aead *geniv;
32
33 if (err == -EINPROGRESS)
34 return;
35
36 if (err)
37 goto out;
38
39 geniv = crypto_aead_reqtfm(req);
40 memcpy(req->iv, subreq->iv, crypto_aead_ivsize(geniv));
41
42out:
43 kzfree(subreq->iv);
44}
45
46static void seqiv_aead_encrypt_complete(struct crypto_async_request *base,
47 int err)
48{
49 struct aead_request *req = base->data;
50
51 seqiv_aead_encrypt_complete2(req, err);
52 aead_request_complete(req, err);
53}
54
Herbert Xu856e3f402015-05-21 15:11:13 +080055static int seqiv_aead_encrypt(struct aead_request *req)
56{
57 struct crypto_aead *geniv = crypto_aead_reqtfm(req);
Herbert Xu659e7f52015-08-13 17:28:59 +080058 struct aead_geniv_ctx *ctx = crypto_aead_ctx(geniv);
Herbert Xu856e3f402015-05-21 15:11:13 +080059 struct aead_request *subreq = aead_request_ctx(req);
60 crypto_completion_t compl;
61 void *data;
62 u8 *info;
Herbert Xudd044462015-05-23 15:41:56 +080063 unsigned int ivsize = 8;
Herbert Xu856e3f402015-05-21 15:11:13 +080064 int err;
65
Herbert Xudd044462015-05-23 15:41:56 +080066 if (req->cryptlen < ivsize)
67 return -EINVAL;
68
Herbert Xu659e7f52015-08-13 17:28:59 +080069 aead_request_set_tfm(subreq, ctx->child);
Herbert Xu856e3f402015-05-21 15:11:13 +080070
71 compl = req->base.complete;
72 data = req->base.data;
73 info = req->iv;
74
Herbert Xu856e3f402015-05-21 15:11:13 +080075 if (req->src != req->dst) {
Herbert Xuef228712016-07-12 13:17:45 +080076 SKCIPHER_REQUEST_ON_STACK(nreq, ctx->sknull);
Herbert Xu856e3f402015-05-21 15:11:13 +080077
Herbert Xuef228712016-07-12 13:17:45 +080078 skcipher_request_set_tfm(nreq, ctx->sknull);
79 skcipher_request_set_callback(nreq, req->base.flags,
80 NULL, NULL);
81 skcipher_request_set_crypt(nreq, req->src, req->dst,
82 req->assoclen + req->cryptlen,
83 NULL);
84
85 err = crypto_skcipher_encrypt(nreq);
Herbert Xu856e3f402015-05-21 15:11:13 +080086 if (err)
87 return err;
88 }
89
90 if (unlikely(!IS_ALIGNED((unsigned long)info,
91 crypto_aead_alignmask(geniv) + 1))) {
92 info = kmalloc(ivsize, req->base.flags &
93 CRYPTO_TFM_REQ_MAY_SLEEP ? GFP_KERNEL:
94 GFP_ATOMIC);
95 if (!info)
96 return -ENOMEM;
97
98 memcpy(info, req->iv, ivsize);
99 compl = seqiv_aead_encrypt_complete;
100 data = req;
101 }
102
103 aead_request_set_callback(subreq, req->base.flags, compl, data);
104 aead_request_set_crypt(subreq, req->dst, req->dst,
105 req->cryptlen - ivsize, info);
Herbert Xu374d4ad2015-05-23 15:41:57 +0800106 aead_request_set_ad(subreq, req->assoclen + ivsize);
Herbert Xu856e3f402015-05-21 15:11:13 +0800107
108 crypto_xor(info, ctx->salt, ivsize);
109 scatterwalk_map_and_copy(info, req->dst, req->assoclen, ivsize, 1);
110
111 err = crypto_aead_encrypt(subreq);
112 if (unlikely(info != req->iv))
113 seqiv_aead_encrypt_complete2(req, err);
114 return err;
115}
116
Herbert Xu856e3f402015-05-21 15:11:13 +0800117static int seqiv_aead_decrypt(struct aead_request *req)
118{
119 struct crypto_aead *geniv = crypto_aead_reqtfm(req);
Herbert Xu659e7f52015-08-13 17:28:59 +0800120 struct aead_geniv_ctx *ctx = crypto_aead_ctx(geniv);
Herbert Xu856e3f402015-05-21 15:11:13 +0800121 struct aead_request *subreq = aead_request_ctx(req);
122 crypto_completion_t compl;
123 void *data;
Herbert Xudd044462015-05-23 15:41:56 +0800124 unsigned int ivsize = 8;
125
126 if (req->cryptlen < ivsize + crypto_aead_authsize(geniv))
127 return -EINVAL;
Herbert Xu856e3f402015-05-21 15:11:13 +0800128
Herbert Xu659e7f52015-08-13 17:28:59 +0800129 aead_request_set_tfm(subreq, ctx->child);
Herbert Xu856e3f402015-05-21 15:11:13 +0800130
131 compl = req->base.complete;
132 data = req->base.data;
133
Herbert Xu856e3f402015-05-21 15:11:13 +0800134 aead_request_set_callback(subreq, req->base.flags, compl, data);
135 aead_request_set_crypt(subreq, req->src, req->dst,
136 req->cryptlen - ivsize, req->iv);
Herbert Xu374d4ad2015-05-23 15:41:57 +0800137 aead_request_set_ad(subreq, req->assoclen + ivsize);
Herbert Xu856e3f402015-05-21 15:11:13 +0800138
139 scatterwalk_map_and_copy(req->iv, req->src, req->assoclen, ivsize, 0);
Herbert Xu856e3f402015-05-21 15:11:13 +0800140
141 return crypto_aead_decrypt(subreq);
142}
143
Herbert Xu06771572015-05-23 15:41:51 +0800144static int seqiv_aead_create(struct crypto_template *tmpl, struct rtattr **tb)
Herbert Xu14df4d82007-12-12 12:27:26 +0800145{
Herbert Xu856e3f402015-05-21 15:11:13 +0800146 struct aead_instance *inst;
Herbert Xu06771572015-05-23 15:41:51 +0800147 int err;
Herbert Xu14df4d82007-12-12 12:27:26 +0800148
Herbert Xu06771572015-05-23 15:41:51 +0800149 inst = aead_geniv_alloc(tmpl, tb, 0, 0);
Herbert Xu14df4d82007-12-12 12:27:26 +0800150
151 if (IS_ERR(inst))
Herbert Xu06771572015-05-23 15:41:51 +0800152 return PTR_ERR(inst);
153
Herbert Xu06771572015-05-23 15:41:51 +0800154 err = -EINVAL;
Herbert Xudd044462015-05-23 15:41:56 +0800155 if (inst->alg.ivsize != sizeof(u64))
Herbert Xu06771572015-05-23 15:41:51 +0800156 goto free_inst;
Herbert Xuc0ecf892015-01-16 19:51:20 +1100157
Herbert Xub7dcfab2015-06-03 14:49:27 +0800158 inst->alg.encrypt = seqiv_aead_encrypt;
Herbert Xu856e3f402015-05-21 15:11:13 +0800159 inst->alg.decrypt = seqiv_aead_decrypt;
Herbert Xu14df4d82007-12-12 12:27:26 +0800160
Herbert Xu659e7f52015-08-13 17:28:59 +0800161 inst->alg.init = aead_init_geniv;
162 inst->alg.exit = aead_exit_geniv;
Herbert Xu856e3f402015-05-21 15:11:13 +0800163
Herbert Xu659e7f52015-08-13 17:28:59 +0800164 inst->alg.base.cra_ctxsize = sizeof(struct aead_geniv_ctx);
Herbert Xu5964f262015-07-09 07:17:22 +0800165 inst->alg.base.cra_ctxsize += inst->alg.ivsize;
Herbert Xu856e3f402015-05-21 15:11:13 +0800166
Herbert Xu06771572015-05-23 15:41:51 +0800167 err = aead_register_instance(tmpl, inst);
168 if (err)
169 goto free_inst;
170
Herbert Xu14df4d82007-12-12 12:27:26 +0800171out:
Herbert Xu06771572015-05-23 15:41:51 +0800172 return err;
173
174free_inst:
175 aead_geniv_free(inst);
176 goto out;
Herbert Xu14df4d82007-12-12 12:27:26 +0800177}
178
Herbert Xu06771572015-05-23 15:41:51 +0800179static int seqiv_create(struct crypto_template *tmpl, struct rtattr **tb)
Herbert Xu14df4d82007-12-12 12:27:26 +0800180{
181 struct crypto_attr_type *algt;
Herbert Xu14df4d82007-12-12 12:27:26 +0800182
183 algt = crypto_get_attr_type(tb);
Herbert Xu14df4d82007-12-12 12:27:26 +0800184 if (IS_ERR(algt))
Herbert Xu06771572015-05-23 15:41:51 +0800185 return PTR_ERR(algt);
Herbert Xu14df4d82007-12-12 12:27:26 +0800186
187 if ((algt->type ^ CRYPTO_ALG_TYPE_AEAD) & CRYPTO_ALG_TYPE_MASK)
Herbert Xu3a01d0e2016-07-12 13:17:50 +0800188 return -EINVAL;
Herbert Xu14df4d82007-12-12 12:27:26 +0800189
Herbert Xu3a01d0e2016-07-12 13:17:50 +0800190 return seqiv_aead_create(tmpl, tb);
Herbert Xu14df4d82007-12-12 12:27:26 +0800191}
192
193static void seqiv_free(struct crypto_instance *inst)
194{
Herbert Xu3a01d0e2016-07-12 13:17:50 +0800195 aead_geniv_free(aead_instance(inst));
Herbert Xu14df4d82007-12-12 12:27:26 +0800196}
197
Herbert Xu0a270322007-11-30 21:38:37 +1100198static struct crypto_template seqiv_tmpl = {
199 .name = "seqiv",
Herbert Xu06771572015-05-23 15:41:51 +0800200 .create = seqiv_create,
Herbert Xu14df4d82007-12-12 12:27:26 +0800201 .free = seqiv_free,
Herbert Xu0a270322007-11-30 21:38:37 +1100202 .module = THIS_MODULE,
203};
204
205static int __init seqiv_module_init(void)
206{
Herbert Xu8a2cd1c2015-08-13 17:28:53 +0800207 return crypto_register_template(&seqiv_tmpl);
Herbert Xu0a270322007-11-30 21:38:37 +1100208}
209
210static void __exit seqiv_module_exit(void)
211{
212 crypto_unregister_template(&seqiv_tmpl);
213}
214
215module_init(seqiv_module_init);
216module_exit(seqiv_module_exit);
217
218MODULE_LICENSE("GPL");
219MODULE_DESCRIPTION("Sequence Number IV Generator");
Kees Cook4943ba12014-11-24 16:32:38 -0800220MODULE_ALIAS_CRYPTO("seqiv");