1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
|
/* In-software asymmetric public-key crypto subtype
*
* See Documentation/crypto/asymmetric-keys.txt
*
* Copyright (C) 2012 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public Licence
* as published by the Free Software Foundation; either version
* 2 of the Licence, or (at your option) any later version.
*/
#define pr_fmt(fmt) "PKEY: "fmt
#include <linux/module.h>
#include <linux/export.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/seq_file.h>
#include <linux/scatterlist.h>
#include <keys/asymmetric-subtype.h>
#include <crypto/public_key.h>
#include <crypto/akcipher.h>
MODULE_DESCRIPTION("In-software asymmetric public-key subtype");
MODULE_AUTHOR("Red Hat, Inc.");
MODULE_LICENSE("GPL");
/*
* Provide a part of a description of the key for /proc/keys.
*/
static void public_key_describe(const struct key *asymmetric_key,
struct seq_file *m)
{
struct public_key *key = asymmetric_key->payload.data[asym_crypto];
if (key)
seq_printf(m, "%s.%s", key->id_type, key->pkey_algo);
}
/*
* Destroy a public key algorithm key.
*/
void public_key_free(struct public_key *key)
{
if (key) {
kfree(key->key);
kfree(key);
}
}
EXPORT_SYMBOL_GPL(public_key_free);
/*
* Destroy a public key algorithm key.
*/
static void public_key_destroy(void *payload0, void *payload3)
{
public_key_free(payload0);
public_key_signature_free(payload3);
}
/*
* Determine the crypto algorithm name.
*/
static
int software_key_determine_akcipher(const char *encoding,
const char *hash_algo,
const struct public_key *pkey,
char alg_name[CRYPTO_MAX_ALG_NAME])
{
int n;
if (strcmp(encoding, "pkcs1") == 0) {
/* The data wangled by the RSA algorithm is typically padded
* and encoded in some manner, such as EMSA-PKCS1-1_5 [RFC3447
* sec 8.2].
*/
if (!hash_algo)
n = snprintf(alg_name, CRYPTO_MAX_ALG_NAME,
"pkcs1pad(%s)",
pkey->pkey_algo);
else
n = snprintf(alg_name, CRYPTO_MAX_ALG_NAME,
"pkcs1pad(%s,%s)",
pkey->pkey_algo, hash_algo);
return n >= CRYPTO_MAX_ALG_NAME ? -EINVAL : 0;
}
if (strcmp(encoding, "raw") == 0) {
strcpy(alg_name, pkey->pkey_algo);
return 0;
}
return -ENOPKG;
}
/*
* Query information about a key.
*/
static int software_key_query(const struct kernel_pkey_params *params,
struct kernel_pkey_query *info)
{
struct crypto_akcipher *tfm;
struct public_key *pkey = params->key->payload.data[asym_crypto];
char alg_name[CRYPTO_MAX_ALG_NAME];
int ret, len;
ret = software_key_determine_akcipher(params->encoding,
params->hash_algo,
pkey, alg_name);
if (ret < 0)
return ret;
tfm = crypto_alloc_akcipher(alg_name, 0, 0);
if (IS_ERR(tfm))
return PTR_ERR(tfm);
if (pkey->key_is_private)
ret = crypto_akcipher_set_priv_key(tfm,
pkey->key, pkey->keylen);
else
ret = crypto_akcipher_set_pub_key(tfm,
pkey->key, pkey->keylen);
if (ret < 0)
goto error_free_tfm;
len = crypto_akcipher_maxsize(tfm);
info->key_size = len * 8;
info->max_data_size = len;
info->max_sig_size = len;
info->max_enc_size = len;
info->max_dec_size = len;
info->supported_ops = (KEYCTL_SUPPORTS_ENCRYPT |
KEYCTL_SUPPORTS_VERIFY);
if (pkey->key_is_private)
info->supported_ops |= (KEYCTL_SUPPORTS_DECRYPT |
KEYCTL_SUPPORTS_SIGN);
ret = 0;
error_free_tfm:
crypto_free_akcipher(tfm);
pr_devel("<==%s() = %d\n", __func__, ret);
return ret;
}
/*
* Do encryption, decryption and signing ops.
*/
static int software_key_eds_op(struct kernel_pkey_params *params,
const void *in, void *out)
{
const struct public_key *pkey = params->key->payload.data[asym_crypto];
struct akcipher_request *req;
struct crypto_akcipher *tfm;
struct crypto_wait cwait;
struct scatterlist in_sg, out_sg;
char alg_name[CRYPTO_MAX_ALG_NAME];
int ret;
pr_devel("==>%s()\n", __func__);
ret = software_key_determine_akcipher(params->encoding,
params->hash_algo,
pkey, alg_name);
if (ret < 0)
return ret;
tfm = crypto_alloc_akcipher(alg_name, 0, 0);
if (IS_ERR(tfm))
return PTR_ERR(tfm);
req = akcipher_request_alloc(tfm, GFP_KERNEL);
if (!req)
goto error_free_tfm;
if (pkey->key_is_private)
ret = crypto_akcipher_set_priv_key(tfm,
pkey->key, pkey->keylen);
else
ret = crypto_akcipher_set_pub_key(tfm,
pkey->key, pkey->keylen);
if (ret)
goto error_free_req;
sg_init_one(&in_sg, in, params->in_len);
sg_init_one(&out_sg, out, params->out_len);
akcipher_request_set_crypt(req, &in_sg, &out_sg, params->in_len,
params->out_len);
crypto_init_wait(&cwait);
akcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG |
CRYPTO_TFM_REQ_MAY_SLEEP,
crypto_req_done, &cwait);
/* Perform the encryption calculation. */
switch (params->op) {
case kernel_pkey_encrypt:
ret = crypto_akcipher_encrypt(req);
break;
case kernel_pkey_decrypt:
ret = crypto_akcipher_decrypt(req);
break;
case kernel_pkey_sign:
ret = crypto_akcipher_sign(req);
break;
default:
BUG();
}
ret = crypto_wait_req(ret, &cwait);
if (ret == 0)
ret = req->dst_len;
error_free_req:
akcipher_request_free(req);
error_free_tfm:
crypto_free_akcipher(tfm);
pr_devel("<==%s() = %d\n", __func__, ret);
return ret;
}
/*
* Verify a signature using a public key.
*/
int public_key_verify_signature(const struct public_key *pkey,
const struct public_key_signature *sig)
{
struct crypto_wait cwait;
struct crypto_akcipher *tfm;
struct akcipher_request *req;
struct scatterlist sig_sg, digest_sg;
char alg_name[CRYPTO_MAX_ALG_NAME];
void *output;
unsigned int outlen;
int ret;
pr_devel("==>%s()\n", __func__);
BUG_ON(!pkey);
BUG_ON(!sig);
BUG_ON(!sig->s);
ret = software_key_determine_akcipher(sig->encoding,
sig->hash_algo,
pkey, alg_name);
if (ret < 0)
return ret;
tfm = crypto_alloc_akcipher(alg_name, 0, 0);
if (IS_ERR(tfm))
return PTR_ERR(tfm);
ret = -ENOMEM;
req = akcipher_request_alloc(tfm, GFP_KERNEL);
if (!req)
goto error_free_tfm;
if (pkey->key_is_private)
ret = crypto_akcipher_set_priv_key(tfm,
pkey->key, pkey->keylen);
else
ret = crypto_akcipher_set_pub_key(tfm,
pkey->key, pkey->keylen);
if (ret)
goto error_free_req;
ret = -ENOMEM;
outlen = crypto_akcipher_maxsize(tfm);
output = kmalloc(outlen, GFP_KERNEL);
if (!output)
goto error_free_req;
sg_init_one(&sig_sg, sig->s, sig->s_size);
sg_init_one(&digest_sg, output, outlen);
akcipher_request_set_crypt(req, &sig_sg, &digest_sg, sig->s_size,
outlen);
crypto_init_wait(&cwait);
akcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG |
CRYPTO_TFM_REQ_MAY_SLEEP,
crypto_req_done, &cwait);
/* Perform the verification calculation. This doesn't actually do the
* verification, but rather calculates the hash expected by the
* signature and returns that to us.
*/
ret = crypto_wait_req(crypto_akcipher_verify(req), &cwait);
if (ret)
goto out_free_output;
/* Do the actual verification step. */
if (req->dst_len != sig->digest_size ||
memcmp(sig->digest, output, sig->digest_size) != 0)
|