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4862bd3c AK |
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 | ||
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 | ||
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 | |
0310641c | 141 | qcrypto_secret_complete(UserCreatable *uc, Error **errp) |
4862bd3c | 142 | { |
0310641c | 143 | QCryptoSecretCommon *secret = QCRYPTO_SECRET_COMMON(uc); |
4862bd3c | 144 | QCryptoSecretCommonClass *sec_class |
0310641c PB |
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); | |
4862bd3c AK |
157 | return; |
158 | } | |
0310641c PB |
159 | } else { |
160 | error_setg(errp, "%s provides no 'load_data' method'", | |
161 | object_get_typename(OBJECT(uc))); | |
162 | return; | |
163 | } | |
4862bd3c | 164 | |
0310641c PB |
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); | |
4862bd3c AK |
179 | g_free(input); |
180 | if (local_err) { | |
181 | error_propagate(errp, local_err); | |
182 | return; | |
183 | } | |
184 | input = output; | |
185 | inputlen = outputlen; | |
4862bd3c | 186 | } |
4862bd3c | 187 | } |
0310641c PB |
188 | |
189 | secret->rawdata = input; | |
190 | secret->rawlen = inputlen; | |
4862bd3c AK |
191 | } |
192 | ||
193 | ||
194 | static bool | |
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 | |
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 | |
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 | |
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 * | |
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 | |
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 * | |
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 | |
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 | |
275 | qcrypto_secret_class_init(ObjectClass *oc, void *data) | |
276 | { | |
31b6aefd KW |
277 | UserCreatableClass *ucc = USER_CREATABLE_CLASS(oc); |
278 | ||
279 | ucc->complete = qcrypto_secret_complete; | |
280 | ||
4862bd3c AK |
281 | object_class_property_add_bool(oc, "loaded", |
282 | qcrypto_secret_prop_get_loaded, | |
0310641c | 283 | NULL); |
4862bd3c AK |
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 | ||
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 | ||
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 | ||
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, | |
31b6aefd KW |
390 | .interfaces = (InterfaceInfo[]) { |
391 | { TYPE_USER_CREATABLE }, | |
392 | { } | |
393 | } | |
4862bd3c AK |
394 | }; |
395 | ||
396 | ||
397 | static 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); |