1 /*
2 * QEMU crypto secret support
3 *
4 * Copyright (c) 2015 Red Hat, Inc.
5 *
6 * This library is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Lesser General Public
8 * License as published by the Free Software Foundation; either
9 * version 2.1 of the License, or (at your option) any later version.
10 *
11 * This library is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * Lesser General Public License for more details.
15 *
16 * You should have received a copy of the GNU Lesser General Public
17 * License along with this library; if not, see <http://www.gnu.org/licenses/>.
18 *
19 */
20
21 #include "qemu/osdep.h"
22 #include "crypto/secret_common.h"
23 #include "crypto/cipher.h"
24 #include "qapi/error.h"
25 #include "qom/object_interfaces.h"
26 #include "qemu/base64.h"
27 #include "qemu/module.h"
28 #include "trace.h"
29
30
qcrypto_secret_decrypt(QCryptoSecretCommon * secret,const uint8_t * input,size_t inputlen,uint8_t ** output,size_t * outputlen,Error ** errp)31 static void qcrypto_secret_decrypt(QCryptoSecretCommon *secret,
32 const uint8_t *input,
33 size_t inputlen,
34 uint8_t **output,
35 size_t *outputlen,
36 Error **errp)
37 {
38 g_autofree uint8_t *iv = NULL;
39 g_autofree uint8_t *key = NULL;
40 g_autofree uint8_t *ciphertext = NULL;
41 size_t keylen, ciphertextlen, ivlen;
42 g_autoptr(QCryptoCipher) aes = NULL;
43 g_autofree uint8_t *plaintext = NULL;
44
45 *output = NULL;
46 *outputlen = 0;
47
48 if (qcrypto_secret_lookup(secret->keyid,
49 &key, &keylen,
50 errp) < 0) {
51 return;
52 }
53
54 if (keylen != 32) {
55 error_setg(errp, "Key should be 32 bytes in length");
56 return;
57 }
58
59 if (!secret->iv) {
60 error_setg(errp, "IV is required to decrypt secret");
61 return;
62 }
63
64 iv = qbase64_decode(secret->iv, -1, &ivlen, errp);
65 if (!iv) {
66 return;
67 }
68 if (ivlen != 16) {
69 error_setg(errp, "IV should be 16 bytes in length not %zu",
70 ivlen);
71 return;
72 }
73
74 aes = qcrypto_cipher_new(QCRYPTO_CIPHER_ALG_AES_256,
75 QCRYPTO_CIPHER_MODE_CBC,
76 key, keylen,
77 errp);
78 if (!aes) {
79 return;
80 }
81
82 if (qcrypto_cipher_setiv(aes, iv, ivlen, errp) < 0) {
83 return;
84 }
85
86 if (secret->format == QCRYPTO_SECRET_FORMAT_BASE64) {
87 ciphertext = qbase64_decode((const gchar *)input,
88 inputlen,
89 &ciphertextlen,
90 errp);
91 if (!ciphertext) {
92 return;
93 }
94 plaintext = g_new0(uint8_t, ciphertextlen + 1);
95 } else {
96 ciphertextlen = inputlen;
97 plaintext = g_new0(uint8_t, inputlen + 1);
98 }
99 if (qcrypto_cipher_decrypt(aes,
100 ciphertext ? ciphertext : input,
101 plaintext,
102 ciphertextlen,
103 errp) < 0) {
104 return;
105 }
106
107 if (plaintext[ciphertextlen - 1] > 16 ||
108 plaintext[ciphertextlen - 1] > ciphertextlen) {
109 error_setg(errp, "Incorrect number of padding bytes (%d) "
110 "found on decrypted data",
111 (int)plaintext[ciphertextlen - 1]);
112 return;
113 }
114
115 /*
116 * Even though plaintext may contain arbitrary NUL
117 * ensure it is explicitly NUL terminated.
118 */
119 ciphertextlen -= plaintext[ciphertextlen - 1];
120 plaintext[ciphertextlen] = '\0';
121
122 *output = g_steal_pointer(&plaintext);
123 *outputlen = ciphertextlen;
124 }
125
126
qcrypto_secret_decode(const uint8_t * input,size_t inputlen,uint8_t ** output,size_t * outputlen,Error ** errp)127 static void qcrypto_secret_decode(const uint8_t *input,
128 size_t inputlen,
129 uint8_t **output,
130 size_t *outputlen,
131 Error **errp)
132 {
133 *output = qbase64_decode((const gchar *)input,
134 inputlen,
135 outputlen,
136 errp);
137 }
138
139
140 static void
qcrypto_secret_complete(UserCreatable * uc,Error ** errp)141 qcrypto_secret_complete(UserCreatable *uc, Error **errp)
142 {
143 QCryptoSecretCommon *secret = QCRYPTO_SECRET_COMMON(uc);
144 QCryptoSecretCommonClass *sec_class
145 = QCRYPTO_SECRET_COMMON_GET_CLASS(uc);
146
147 Error *local_err = NULL;
148 uint8_t *input = NULL;
149 size_t inputlen = 0;
150 uint8_t *output = NULL;
151 size_t outputlen = 0;
152
153 if (sec_class->load_data) {
154 sec_class->load_data(secret, &input, &inputlen, &local_err);
155 if (local_err) {
156 error_propagate(errp, local_err);
157 return;
158 }
159 } else {
160 error_setg(errp, "%s provides no 'load_data' method'",
161 object_get_typename(OBJECT(uc)));
162 return;
163 }
164
165 if (secret->keyid) {
166 qcrypto_secret_decrypt(secret, input, inputlen,
167 &output, &outputlen, &local_err);
168 g_free(input);
169 if (local_err) {
170 error_propagate(errp, local_err);
171 return;
172 }
173 input = output;
174 inputlen = outputlen;
175 } else {
176 if (secret->format == QCRYPTO_SECRET_FORMAT_BASE64) {
177 qcrypto_secret_decode(input, inputlen,
178 &output, &outputlen, &local_err);
179 g_free(input);
180 if (local_err) {
181 error_propagate(errp, local_err);
182 return;
183 }
184 input = output;
185 inputlen = outputlen;
186 }
187 }
188
189 secret->rawdata = input;
190 secret->rawlen = inputlen;
191 }
192
193
194 static bool
qcrypto_secret_prop_get_loaded(Object * obj,Error ** errp G_GNUC_UNUSED)195 qcrypto_secret_prop_get_loaded(Object *obj,
196 Error **errp G_GNUC_UNUSED)
197 {
198 QCryptoSecretCommon *secret = QCRYPTO_SECRET_COMMON(obj);
199 return secret->rawdata != NULL;
200 }
201
202
203 static void
qcrypto_secret_prop_set_format(Object * obj,int value,Error ** errp G_GNUC_UNUSED)204 qcrypto_secret_prop_set_format(Object *obj,
205 int value,
206 Error **errp G_GNUC_UNUSED)
207 {
208 QCryptoSecretCommon *creds = QCRYPTO_SECRET_COMMON(obj);
209 creds->format = value;
210 }
211
212
213 static int
qcrypto_secret_prop_get_format(Object * obj,Error ** errp G_GNUC_UNUSED)214 qcrypto_secret_prop_get_format(Object *obj,
215 Error **errp G_GNUC_UNUSED)
216 {
217 QCryptoSecretCommon *creds = QCRYPTO_SECRET_COMMON(obj);
218 return creds->format;
219 }
220
221
222 static void
qcrypto_secret_prop_set_iv(Object * obj,const char * value,Error ** errp)223 qcrypto_secret_prop_set_iv(Object *obj,
224 const char *value,
225 Error **errp)
226 {
227 QCryptoSecretCommon *secret = QCRYPTO_SECRET_COMMON(obj);
228
229 g_free(secret->iv);
230 secret->iv = g_strdup(value);
231 }
232
233
234 static char *
qcrypto_secret_prop_get_iv(Object * obj,Error ** errp)235 qcrypto_secret_prop_get_iv(Object *obj,
236 Error **errp)
237 {
238 QCryptoSecretCommon *secret = QCRYPTO_SECRET_COMMON(obj);
239 return g_strdup(secret->iv);
240 }
241
242
243 static void
qcrypto_secret_prop_set_keyid(Object * obj,const char * value,Error ** errp)244 qcrypto_secret_prop_set_keyid(Object *obj,
245 const char *value,
246 Error **errp)
247 {
248 QCryptoSecretCommon *secret = QCRYPTO_SECRET_COMMON(obj);
249
250 g_free(secret->keyid);
251 secret->keyid = g_strdup(value);
252 }
253
254
255 static char *
qcrypto_secret_prop_get_keyid(Object * obj,Error ** errp)256 qcrypto_secret_prop_get_keyid(Object *obj,
257 Error **errp)
258 {
259 QCryptoSecretCommon *secret = QCRYPTO_SECRET_COMMON(obj);
260 return g_strdup(secret->keyid);
261 }
262
263
264 static void
qcrypto_secret_finalize(Object * obj)265 qcrypto_secret_finalize(Object *obj)
266 {
267 QCryptoSecretCommon *secret = QCRYPTO_SECRET_COMMON(obj);
268
269 g_free(secret->iv);
270 g_free(secret->keyid);
271 g_free(secret->rawdata);
272 }
273
274 static void
qcrypto_secret_class_init(ObjectClass * oc,void * data)275 qcrypto_secret_class_init(ObjectClass *oc, void *data)
276 {
277 UserCreatableClass *ucc = USER_CREATABLE_CLASS(oc);
278
279 ucc->complete = qcrypto_secret_complete;
280
281 object_class_property_add_bool(oc, "loaded",
282 qcrypto_secret_prop_get_loaded,
283 NULL);
284 object_class_property_add_enum(oc, "format",
285 "QCryptoSecretFormat",
286 &QCryptoSecretFormat_lookup,
287 qcrypto_secret_prop_get_format,
288 qcrypto_secret_prop_set_format);
289 object_class_property_add_str(oc, "keyid",
290 qcrypto_secret_prop_get_keyid,
291 qcrypto_secret_prop_set_keyid);
292 object_class_property_add_str(oc, "iv",
293 qcrypto_secret_prop_get_iv,
294 qcrypto_secret_prop_set_iv);
295 }
296
297
qcrypto_secret_lookup(const char * secretid,uint8_t ** data,size_t * datalen,Error ** errp)298 int qcrypto_secret_lookup(const char *secretid,
299 uint8_t **data,
300 size_t *datalen,
301 Error **errp)
302 {
303 Object *obj;
304 QCryptoSecretCommon *secret;
305
306 obj = object_resolve_path_component(
307 object_get_objects_root(), secretid);
308 if (!obj) {
309 error_setg(errp, "No secret with id '%s'", secretid);
310 return -1;
311 }
312
313 secret = (QCryptoSecretCommon *)
314 object_dynamic_cast(obj,
315 TYPE_QCRYPTO_SECRET_COMMON);
316 if (!secret) {
317 error_setg(errp, "Object with id '%s' is not a secret",
318 secretid);
319 return -1;
320 }
321
322 if (!secret->rawdata) {
323 error_setg(errp, "Secret with id '%s' has no data",
324 secretid);
325 return -1;
326 }
327
328 *data = g_new0(uint8_t, secret->rawlen + 1);
329 memcpy(*data, secret->rawdata, secret->rawlen);
330 (*data)[secret->rawlen] = '\0';
331 *datalen = secret->rawlen;
332
333 return 0;
334 }
335
336
qcrypto_secret_lookup_as_utf8(const char * secretid,Error ** errp)337 char *qcrypto_secret_lookup_as_utf8(const char *secretid,
338 Error **errp)
339 {
340 uint8_t *data;
341 size_t datalen;
342
343 if (qcrypto_secret_lookup(secretid,
344 &data,
345 &datalen,
346 errp) < 0) {
347 return NULL;
348 }
349
350 if (!g_utf8_validate((const gchar *)data, datalen, NULL)) {
351 error_setg(errp,
352 "Data from secret %s is not valid UTF-8",
353 secretid);
354 g_free(data);
355 return NULL;
356 }
357
358 return (char *)data;
359 }
360
361
qcrypto_secret_lookup_as_base64(const char * secretid,Error ** errp)362 char *qcrypto_secret_lookup_as_base64(const char *secretid,
363 Error **errp)
364 {
365 uint8_t *data;
366 size_t datalen;
367 char *ret;
368
369 if (qcrypto_secret_lookup(secretid,
370 &data,
371 &datalen,
372 errp) < 0) {
373 return NULL;
374 }
375
376 ret = g_base64_encode(data, datalen);
377 g_free(data);
378 return ret;
379 }
380
381
382 static const TypeInfo qcrypto_secret_info = {
383 .parent = TYPE_OBJECT,
384 .name = TYPE_QCRYPTO_SECRET_COMMON,
385 .instance_size = sizeof(QCryptoSecretCommon),
386 .instance_finalize = qcrypto_secret_finalize,
387 .class_size = sizeof(QCryptoSecretCommonClass),
388 .class_init = qcrypto_secret_class_init,
389 .abstract = true,
390 .interfaces = (InterfaceInfo[]) {
391 { TYPE_USER_CREATABLE },
392 { }
393 }
394 };
395
396
397 static void
qcrypto_secret_register_types(void)398 qcrypto_secret_register_types(void)
399 {
400 type_register_static(&qcrypto_secret_info);
401 }
402
403
404 type_init(qcrypto_secret_register_types);
405