summaryrefslogtreecommitdiff
path: root/security/keys/keyctl_pkey.c
blob: 5de0d599a2748f50f3f4b144b8440f08bc57581b (plain)
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
// SPDX-License-Identifier: GPL-2.0-or-later
/* Public-key operation keyctls
 *
 * Copyright (C) 2016 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells (dhowells@redhat.com)
 */

#include <linux/slab.h>
#include <linux/err.h>
#include <linux/key.h>
#include <linux/keyctl.h>
#include <linux/parser.h>
#include <linux/uaccess.h>
#include <keys/user-type.h>
#include "internal.h"

static void keyctl_pkey_params_free(struct kernel_pkey_params *params)
{
	kfree(params->info);
	key_put(params->key);
}

enum {
	Opt_err,
	Opt_enc,		/* "enc=<encoding>" eg. "enc=oaep" */
	Opt_hash,		/* "hash=<digest-name>" eg. "hash=sha1" */
};

static const match_table_t param_keys = {
	{ Opt_enc,	"enc=%s" },
	{ Opt_hash,	"hash=%s" },
	{ Opt_err,	NULL }
};

/*
 * Parse the information string which consists of key=val pairs.
 */
static int keyctl_pkey_params_parse(struct kernel_pkey_params *params)
{
	unsigned long token_mask = 0;
	substring_t args[MAX_OPT_ARGS];
	char *c = params->info, *p, *q;
	int token;

	while ((p = strsep(&c, " \t"))) {
		if (*p == '\0' || *p == ' ' || *p == '\t')
			continue;
		token = match_token(p, param_keys, args);
		if (token == Opt_err)
			return -EINVAL;
		if (__test_and_set_bit(token, &token_mask))
			return -EINVAL;
		q = args[0].from;
		if (!q[0])
			return -EINVAL;

		switch (token) {
		case Opt_enc:
			params->encoding = q;
			break;

		case Opt_hash:
			params->hash_algo = q;
			break;

		default:
			return -EINVAL;
		}
	}

	return 0;
}

/*
 * Interpret parameters.  Callers must always call the free function
 * on params, even if an error is returned.
 */
static int keyctl_pkey_params_get(key_serial_t id,
				  const char __user *_info,
				  struct kernel_pkey_params *params)
{
	key_ref_t key_ref;
	void *p;
	int ret;

	memset(params, 0, sizeof(*params));
	params->encoding = "raw";

	p = strndup_user(_info, PAGE_SIZE);
	if (IS_ERR(p))
		return PTR_ERR(p);
	params->info = p;

	ret = keyctl_pkey_params_parse(params);
	if (ret < 0)
		return ret;

	key_ref = lookup_user_key(id, 0, KEY_NEED_SEARCH);
	if (IS_ERR(key_ref))
		return PTR_ERR(key_ref);
	params->key = key_ref_to_ptr(key_ref);

	if (!params->key->type->asym_query)
		return -EOPNOTSUPP;

	return 0;
}

/*
 * Get parameters from userspace.  Callers must always call the free function
 * on params, even if an error is returned.
 */
static int keyctl_pkey_params_get_2(const struct keyctl_pkey_params __user *_params,
				    const char __user *_info,
				    int op,
				    struct kernel_pkey_params *params)
{
	struct keyctl_pkey_params uparams;
	struct kernel_pkey_query info;
	int ret;

	memset(params, 0, sizeof(*params));
	params->encoding = "raw";

	if (copy_from_user(&uparams, _params, sizeof(uparams)) != 0)
		return -EFAULT;

	ret = keyctl_pkey_params_get(uparams.key_id, _info, params);
	if (ret < 0)
		return ret;

	ret = params->key->type->asym_query(params, &info);
	if (ret < 0)
		return ret;

	switch (op) {
	case KEYCTL_PKEY_ENCRYPT:
	case KEYCTL_PKEY_DECRYPT:
		if (uparams.in_len  > info.max_enc_size ||
		    uparams.out_len > info.max_dec_size)
			return -EINVAL;
		break;
	case KEYCTL_PKEY_SIGN:
	case KEYCTL_PKEY_VERIFY:
		if (uparams.in_len  > info.max_sig_size ||
		    uparams.out_len > info.max_data_size)
			return -EINVAL;
		break;
	default:
		BUG();
	}

	params->in_len  = uparams.in_len;
	params->out_len = uparams.out_len;
	return 0;
}

/*
 * Query information about an asymmetric key.
 */
long keyctl_pkey_query(key_serial_t id,
		       const char __user *_info,
		       struct keyctl_pkey_query __user *_res)
{
	struct kernel_pkey_params params;
	struct kernel_pkey_query res;
	long ret;

	ret = keyctl_pkey_params_get(id, _info, &params);
	if (ret < 0)
		goto error;

	ret = params.key->type->asym_query(&params, &res);
	if (ret < 0)
		goto error;

	ret = -EFAULT;
	if (copy_to_user(_res, &res, sizeof(res)) == 0 &&
	    clear_user(_res->__spare, sizeof(_res->__spare)) == 0)
		ret = 0;

error:
	keyctl_pkey_params_free(&params);
	return ret;
}

/*
 * Encrypt/decrypt/sign
 *
 * Encrypt data, decrypt data or sign data using a public key.
 *
 * _info is a string of supplementary information in key=val format.  For
 * instance, it might contain:
 *
 *	"enc=pkcs1 hash=sha256"
 *
 * where enc= specifies the encoding and hash= selects the OID to go in that
 * particular encoding if required.  If enc= isn't supplied, it's assumed that
 * the caller is supplying raw values.
 *
 * If successful, the amount of data written into the output buffer is
 * returned.
 */
long keyctl_pkey_e_d_s(int op,
		       const struct keyctl_pkey_params __user *_params,
		       const char __user *_info,
		       const void __user *_in,
		       void __user *_out)
{
	struct kernel_pkey_params params;
	void *in, *out;
	long ret;

	ret = keyctl_pkey_params_get_2(_params, _info, op, &params);
	if (ret < 0)
		goto error_params;

	ret = -EOPNOTSUPP;
	if (!params.key->type->asym_eds_op)
		goto error_params;

	switch (op) {
	case KEYCTL_PKEY_ENCRYPT:
		params.op = kernel_pkey_encrypt;
		break;
	case KEYCTL_PKEY_DECRYPT:
		params.op = kernel_pkey_decrypt;
		break;
	case KEYCTL_PKEY_SIGN:
		params.op = kernel_pkey_sign;
		break;
	default:
		BUG();
	}

	in = memdup_user(_in, params.in_len);
	if (IS_ERR(in)) {
		ret = PTR_ERR(in);
		goto error_params;
	}

	ret = -ENOMEM;
	out = kmalloc(params.out_len, GFP_KERNEL);
	if (!out)
		goto error_in;

	ret = params.key->type->asym_eds_op(&params, in, out);
	if (ret < 0)
		goto error_out;

	if (copy_to_user(_out, out, ret) != 0)
		ret = -EFAULT;

error_out:
	kfree(out);
error_in:
	kfree(in);
error_params:
	keyctl_pkey_params_free(&params);
	return ret;
}

/*
 * Verify a signature.
 *
 * Verify a public key signature using the given key, or if not given, search
 * for a matching key.
 *
 * _info is a string of supplementary information in key=val format.  For
 * instance, it might contain:
 *
 *	"enc=pkcs1 hash=sha256"
 *
 * where enc= specifies the signature blob encoding and hash= selects the OID
 * to go in that particular encoding.  If enc= isn't supplied, it's assumed
 * that the caller is supplying raw values.
 *
 * If successful, 0 is returned.
 */
long keyctl_pkey_verify(const struct keyctl_pkey_params __user *_params,
			const char __user *_info,
			const void __user *_in,
			const void __user *_in2)
{
	struct kernel_pkey_params params;
	void *in, *in2;
	long ret;

	ret = keyctl_pkey_params_get_2(_params, _info, KEYCTL_PKEY_VERIFY,
				       &params);
	if (ret < 0)
		goto error_params;

	ret = -EOPNOTSUPP;
	if (!params.key->type->asym_verify_signature)
		goto error_params;

	in = memdup_user(_in, params.in_len);
	if (IS_ERR(in)) {
		ret = PTR_ERR(in);
		goto error_params;
	}

	in2 = memdup_user(_in2, params.in2_len);
	if (IS_ERR(in2)) {
		ret = PTR_ERR(in2);
		goto error_in;
	}

	params.op = kernel_pkey_verify;
	ret = params.key->type->asym_verify_signature(&params, in, in2);

	kfree(in2);
error_in:
	kfree(in);
error_params:
	keyctl_pkey_params_free(&params);
	return ret;
}