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[mirror_ubuntu-bionic-kernel.git] / 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
661cfd0e 16#include <crypto/internal/geniv.h>
856e3f40 17#include <crypto/scatterwalk.h>
3a01d0ee 18#include <crypto/skcipher.h>
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19#include <linux/err.h>
20#include <linux/init.h>
21#include <linux/kernel.h>
22#include <linux/module.h>
5a0e3ad6 23#include <linux/slab.h>
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24#include <linux/string.h>
25
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26static void seqiv_free(struct crypto_instance *inst);
27
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28static 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
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55static int seqiv_aead_encrypt(struct aead_request *req)
56{
57 struct crypto_aead *geniv = crypto_aead_reqtfm(req);
659e7f52 58 struct aead_geniv_ctx *ctx = crypto_aead_ctx(geniv);
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59 struct aead_request *subreq = aead_request_ctx(req);
60 crypto_completion_t compl;
61 void *data;
62 u8 *info;
dd04446e 63 unsigned int ivsize = 8;
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64 int err;
65
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66 if (req->cryptlen < ivsize)
67 return -EINVAL;
68
659e7f52 69 aead_request_set_tfm(subreq, ctx->child);
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70
71 compl = req->base.complete;
72 data = req->base.data;
73 info = req->iv;
74
856e3f40 75 if (req->src != req->dst) {
ef22871f 76 SKCIPHER_REQUEST_ON_STACK(nreq, ctx->sknull);
856e3f40 77
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78 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);
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86 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);
374d4ad1 106 aead_request_set_ad(subreq, req->assoclen + ivsize);
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107
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
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117static int seqiv_aead_decrypt(struct aead_request *req)
118{
119 struct crypto_aead *geniv = crypto_aead_reqtfm(req);
659e7f52 120 struct aead_geniv_ctx *ctx = crypto_aead_ctx(geniv);
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121 struct aead_request *subreq = aead_request_ctx(req);
122 crypto_completion_t compl;
123 void *data;
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124 unsigned int ivsize = 8;
125
126 if (req->cryptlen < ivsize + crypto_aead_authsize(geniv))
127 return -EINVAL;
856e3f40 128
659e7f52 129 aead_request_set_tfm(subreq, ctx->child);
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130
131 compl = req->base.complete;
132 data = req->base.data;
133
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134 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);
374d4ad1 137 aead_request_set_ad(subreq, req->assoclen + ivsize);
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138
139 scatterwalk_map_and_copy(req->iv, req->src, req->assoclen, ivsize, 0);
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140
141 return crypto_aead_decrypt(subreq);
142}
143
0677157b 144static int seqiv_aead_create(struct crypto_template *tmpl, struct rtattr **tb)
14df4d80 145{
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146 struct aead_instance *inst;
147 struct crypto_aead_spawn *spawn;
148 struct aead_alg *alg;
0677157b 149 int err;
14df4d80 150
0677157b 151 inst = aead_geniv_alloc(tmpl, tb, 0, 0);
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152
153 if (IS_ERR(inst))
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154 return PTR_ERR(inst);
155
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156 spawn = aead_instance_ctx(inst);
157 alg = crypto_spawn_aead_alg(spawn);
158
0677157b 159 err = -EINVAL;
dd04446e 160 if (inst->alg.ivsize != sizeof(u64))
0677157b 161 goto free_inst;
c0ecf891 162
b7dcfab4 163 inst->alg.encrypt = seqiv_aead_encrypt;
856e3f40 164 inst->alg.decrypt = seqiv_aead_decrypt;
14df4d80 165
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166 inst->alg.init = aead_init_geniv;
167 inst->alg.exit = aead_exit_geniv;
856e3f40 168
659e7f52 169 inst->alg.base.cra_ctxsize = sizeof(struct aead_geniv_ctx);
5964f26c 170 inst->alg.base.cra_ctxsize += inst->alg.ivsize;
856e3f40 171
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172 err = aead_register_instance(tmpl, inst);
173 if (err)
174 goto free_inst;
175
14df4d80 176out:
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177 return err;
178
179free_inst:
180 aead_geniv_free(inst);
181 goto out;
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182}
183
0677157b 184static int seqiv_create(struct crypto_template *tmpl, struct rtattr **tb)
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185{
186 struct crypto_attr_type *algt;
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187
188 algt = crypto_get_attr_type(tb);
14df4d80 189 if (IS_ERR(algt))
0677157b 190 return PTR_ERR(algt);
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191
192 if ((algt->type ^ CRYPTO_ALG_TYPE_AEAD) & CRYPTO_ALG_TYPE_MASK)
3a01d0ee 193 return -EINVAL;
14df4d80 194
3a01d0ee 195 return seqiv_aead_create(tmpl, tb);
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196}
197
198static void seqiv_free(struct crypto_instance *inst)
199{
3a01d0ee 200 aead_geniv_free(aead_instance(inst));
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201}
202
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203static struct crypto_template seqiv_tmpl = {
204 .name = "seqiv",
0677157b 205 .create = seqiv_create,
14df4d80 206 .free = seqiv_free,
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207 .module = THIS_MODULE,
208};
209
210static int __init seqiv_module_init(void)
211{
8a2cd1c4 212 return crypto_register_template(&seqiv_tmpl);
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213}
214
215static void __exit seqiv_module_exit(void)
216{
217 crypto_unregister_template(&seqiv_tmpl);
218}
219
220module_init(seqiv_module_init);
221module_exit(seqiv_module_exit);
222
223MODULE_LICENSE("GPL");
224MODULE_DESCRIPTION("Sequence Number IV Generator");
4943ba16 225MODULE_ALIAS_CRYPTO("seqiv");