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16#include <crypto/internal/geniv.h>
17#include <crypto/scatterwalk.h>
18#include <crypto/skcipher.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/string.h>
25
26static void seqiv_free(struct crypto_instance *inst);
27
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
55static int seqiv_aead_encrypt(struct aead_request *req)
56{
57 struct crypto_aead *geniv = crypto_aead_reqtfm(req);
58 struct aead_geniv_ctx *ctx = crypto_aead_ctx(geniv);
59 struct aead_request *subreq = aead_request_ctx(req);
60 crypto_completion_t compl;
61 void *data;
62 u8 *info;
63 unsigned int ivsize = 8;
64 int err;
65
66 if (req->cryptlen < ivsize)
67 return -EINVAL;
68
69 aead_request_set_tfm(subreq, ctx->child);
70
71 compl = req->base.complete;
72 data = req->base.data;
73 info = req->iv;
74
75 if (req->src != req->dst) {
76 SKCIPHER_REQUEST_ON_STACK(nreq, ctx->sknull);
77
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);
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);
106 aead_request_set_ad(subreq, req->assoclen + ivsize);
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
117static int seqiv_aead_decrypt(struct aead_request *req)
118{
119 struct crypto_aead *geniv = crypto_aead_reqtfm(req);
120 struct aead_geniv_ctx *ctx = crypto_aead_ctx(geniv);
121 struct aead_request *subreq = aead_request_ctx(req);
122 crypto_completion_t compl;
123 void *data;
124 unsigned int ivsize = 8;
125
126 if (req->cryptlen < ivsize + crypto_aead_authsize(geniv))
127 return -EINVAL;
128
129 aead_request_set_tfm(subreq, ctx->child);
130
131 compl = req->base.complete;
132 data = req->base.data;
133
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);
137 aead_request_set_ad(subreq, req->assoclen + ivsize);
138
139 scatterwalk_map_and_copy(req->iv, req->src, req->assoclen, ivsize, 0);
140
141 return crypto_aead_decrypt(subreq);
142}
143
144static int seqiv_aead_create(struct crypto_template *tmpl, struct rtattr **tb)
145{
146 struct aead_instance *inst;
147 int err;
148
149 inst = aead_geniv_alloc(tmpl, tb, 0, 0);
150
151 if (IS_ERR(inst))
152 return PTR_ERR(inst);
153
154 err = -EINVAL;
155 if (inst->alg.ivsize != sizeof(u64))
156 goto free_inst;
157
158 inst->alg.encrypt = seqiv_aead_encrypt;
159 inst->alg.decrypt = seqiv_aead_decrypt;
160
161 inst->alg.init = aead_init_geniv;
162 inst->alg.exit = aead_exit_geniv;
163
164 inst->alg.base.cra_ctxsize = sizeof(struct aead_geniv_ctx);
165 inst->alg.base.cra_ctxsize += inst->alg.ivsize;
166
167 err = aead_register_instance(tmpl, inst);
168 if (err)
169 goto free_inst;
170
171out:
172 return err;
173
174free_inst:
175 aead_geniv_free(inst);
176 goto out;
177}
178
179static int seqiv_create(struct crypto_template *tmpl, struct rtattr **tb)
180{
181 struct crypto_attr_type *algt;
182
183 algt = crypto_get_attr_type(tb);
184 if (IS_ERR(algt))
185 return PTR_ERR(algt);
186
187 if ((algt->type ^ CRYPTO_ALG_TYPE_AEAD) & CRYPTO_ALG_TYPE_MASK)
188 return -EINVAL;
189
190 return seqiv_aead_create(tmpl, tb);
191}
192
193static void seqiv_free(struct crypto_instance *inst)
194{
195 aead_geniv_free(aead_instance(inst));
196}
197
198static struct crypto_template seqiv_tmpl = {
199 .name = "seqiv",
200 .create = seqiv_create,
201 .free = seqiv_free,
202 .module = THIS_MODULE,
203};
204
205static int __init seqiv_module_init(void)
206{
207 return crypto_register_template(&seqiv_tmpl);
208}
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");
220MODULE_ALIAS_CRYPTO("seqiv");
221
