util: rename qemu_open() to qemu_open_old()
[qemu.git] / backends / tpm / tpm_passthrough.c
1 /*
2 * passthrough TPM driver
3 *
4 * Copyright (c) 2010 - 2013 IBM Corporation
5 * Authors:
6 * Stefan Berger <stefanb@us.ibm.com>
7 *
8 * Copyright (C) 2011 IAIK, Graz University of Technology
9 * Author: Andreas Niederl
10 *
11 * This library is free software; you can redistribute it and/or
12 * modify it under the terms of the GNU Lesser General Public
13 * License as published by the Free Software Foundation; either
14 * version 2 of the License, or (at your option) any later version.
15 *
16 * This library is distributed in the hope that it will be useful,
17 * but WITHOUT ANY WARRANTY; without even the implied warranty of
18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
19 * Lesser General Public License for more details.
20 *
21 * You should have received a copy of the GNU Lesser General Public
22 * License along with this library; if not, see <http://www.gnu.org/licenses/>
23 */
24
25 #include "qemu/osdep.h"
26 #include "qemu-common.h"
27 #include "qemu/error-report.h"
28 #include "qemu/module.h"
29 #include "qemu/sockets.h"
30 #include "sysemu/tpm_backend.h"
31 #include "sysemu/tpm_util.h"
32 #include "tpm_int.h"
33 #include "qapi/clone-visitor.h"
34 #include "qapi/qapi-visit-tpm.h"
35 #include "trace.h"
36 #include "qom/object.h"
37
38 #define TYPE_TPM_PASSTHROUGH "tpm-passthrough"
39 typedef struct TPMPassthruState TPMPassthruState;
40 DECLARE_INSTANCE_CHECKER(TPMPassthruState, TPM_PASSTHROUGH,
41 TYPE_TPM_PASSTHROUGH)
42
43 /* data structures */
44 struct TPMPassthruState {
45 TPMBackend parent;
46
47 TPMPassthroughOptions *options;
48 const char *tpm_dev;
49 int tpm_fd;
50 bool tpm_executing;
51 bool tpm_op_canceled;
52 int cancel_fd;
53
54 TPMVersion tpm_version;
55 size_t tpm_buffersize;
56 };
57
58
59 #define TPM_PASSTHROUGH_DEFAULT_DEVICE "/dev/tpm0"
60
61 /* functions */
62
63 static void tpm_passthrough_cancel_cmd(TPMBackend *tb);
64
65 static int tpm_passthrough_unix_read(int fd, uint8_t *buf, uint32_t len)
66 {
67 int ret;
68 reread:
69 ret = read(fd, buf, len);
70 if (ret < 0) {
71 if (errno != EINTR && errno != EAGAIN) {
72 return -1;
73 }
74 goto reread;
75 }
76 return ret;
77 }
78
79 static void tpm_passthrough_unix_tx_bufs(TPMPassthruState *tpm_pt,
80 const uint8_t *in, uint32_t in_len,
81 uint8_t *out, uint32_t out_len,
82 bool *selftest_done, Error **errp)
83 {
84 ssize_t ret;
85 bool is_selftest;
86
87 /* FIXME: protect shared variables or use other sync mechanism */
88 tpm_pt->tpm_op_canceled = false;
89 tpm_pt->tpm_executing = true;
90 *selftest_done = false;
91
92 is_selftest = tpm_util_is_selftest(in, in_len);
93
94 ret = qemu_write_full(tpm_pt->tpm_fd, in, in_len);
95 if (ret != in_len) {
96 if (!tpm_pt->tpm_op_canceled || errno != ECANCELED) {
97 error_setg_errno(errp, errno, "tpm_passthrough: error while "
98 "transmitting data to TPM");
99 }
100 goto err_exit;
101 }
102
103 tpm_pt->tpm_executing = false;
104
105 ret = tpm_passthrough_unix_read(tpm_pt->tpm_fd, out, out_len);
106 if (ret < 0) {
107 if (!tpm_pt->tpm_op_canceled || errno != ECANCELED) {
108 error_setg_errno(errp, errno, "tpm_passthrough: error while "
109 "reading data from TPM");
110 }
111 } else if (ret < sizeof(struct tpm_resp_hdr) ||
112 tpm_cmd_get_size(out) != ret) {
113 ret = -1;
114 error_setg_errno(errp, errno, "tpm_passthrough: received invalid "
115 "response packet from TPM");
116 }
117
118 if (is_selftest && (ret >= sizeof(struct tpm_resp_hdr))) {
119 *selftest_done = tpm_cmd_get_errcode(out) == 0;
120 }
121
122 err_exit:
123 if (ret < 0) {
124 tpm_util_write_fatal_error_response(out, out_len);
125 }
126
127 tpm_pt->tpm_executing = false;
128 }
129
130 static void tpm_passthrough_handle_request(TPMBackend *tb, TPMBackendCmd *cmd,
131 Error **errp)
132 {
133 TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(tb);
134
135 trace_tpm_passthrough_handle_request(cmd);
136
137 tpm_passthrough_unix_tx_bufs(tpm_pt, cmd->in, cmd->in_len,
138 cmd->out, cmd->out_len, &cmd->selftest_done,
139 errp);
140 }
141
142 static void tpm_passthrough_reset(TPMBackend *tb)
143 {
144 trace_tpm_passthrough_reset();
145
146 tpm_passthrough_cancel_cmd(tb);
147 }
148
149 static bool tpm_passthrough_get_tpm_established_flag(TPMBackend *tb)
150 {
151 return false;
152 }
153
154 static int tpm_passthrough_reset_tpm_established_flag(TPMBackend *tb,
155 uint8_t locty)
156 {
157 /* only a TPM 2.0 will support this */
158 return 0;
159 }
160
161 static void tpm_passthrough_cancel_cmd(TPMBackend *tb)
162 {
163 TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(tb);
164 int n;
165
166 /*
167 * As of Linux 3.7 the tpm_tis driver does not properly cancel
168 * commands on all TPM manufacturers' TPMs.
169 * Only cancel if we're busy so we don't cancel someone else's
170 * command, e.g., a command executed on the host.
171 */
172 if (tpm_pt->tpm_executing) {
173 if (tpm_pt->cancel_fd >= 0) {
174 tpm_pt->tpm_op_canceled = true;
175 n = write(tpm_pt->cancel_fd, "-", 1);
176 if (n != 1) {
177 error_report("Canceling TPM command failed: %s",
178 strerror(errno));
179 }
180 } else {
181 error_report("Cannot cancel TPM command due to missing "
182 "TPM sysfs cancel entry");
183 }
184 }
185 }
186
187 static TPMVersion tpm_passthrough_get_tpm_version(TPMBackend *tb)
188 {
189 TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(tb);
190
191 return tpm_pt->tpm_version;
192 }
193
194 static size_t tpm_passthrough_get_buffer_size(TPMBackend *tb)
195 {
196 TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(tb);
197 int ret;
198
199 ret = tpm_util_get_buffer_size(tpm_pt->tpm_fd, tpm_pt->tpm_version,
200 &tpm_pt->tpm_buffersize);
201 if (ret < 0) {
202 tpm_pt->tpm_buffersize = 4096;
203 }
204 return tpm_pt->tpm_buffersize;
205 }
206
207 /*
208 * Unless path or file descriptor set has been provided by user,
209 * determine the sysfs cancel file following kernel documentation
210 * in Documentation/ABI/stable/sysfs-class-tpm.
211 * From /dev/tpm0 create /sys/class/tpm/tpm0/device/cancel
212 * before 4.0: /sys/class/misc/tpm0/device/cancel
213 */
214 static int tpm_passthrough_open_sysfs_cancel(TPMPassthruState *tpm_pt)
215 {
216 int fd = -1;
217 char *dev;
218 char path[PATH_MAX];
219
220 if (tpm_pt->options->cancel_path) {
221 fd = qemu_open_old(tpm_pt->options->cancel_path, O_WRONLY);
222 if (fd < 0) {
223 error_report("tpm_passthrough: Could not open TPM cancel path: %s",
224 strerror(errno));
225 }
226 return fd;
227 }
228
229 dev = strrchr(tpm_pt->tpm_dev, '/');
230 if (!dev) {
231 error_report("tpm_passthrough: Bad TPM device path %s",
232 tpm_pt->tpm_dev);
233 return -1;
234 }
235
236 dev++;
237 if (snprintf(path, sizeof(path), "/sys/class/tpm/%s/device/cancel",
238 dev) < sizeof(path)) {
239 fd = qemu_open_old(path, O_WRONLY);
240 if (fd < 0) {
241 if (snprintf(path, sizeof(path), "/sys/class/misc/%s/device/cancel",
242 dev) < sizeof(path)) {
243 fd = qemu_open_old(path, O_WRONLY);
244 }
245 }
246 }
247
248 if (fd < 0) {
249 error_report("tpm_passthrough: Could not guess TPM cancel path");
250 } else {
251 tpm_pt->options->cancel_path = g_strdup(path);
252 }
253
254 return fd;
255 }
256
257 static int
258 tpm_passthrough_handle_device_opts(TPMPassthruState *tpm_pt, QemuOpts *opts)
259 {
260 const char *value;
261
262 value = qemu_opt_get(opts, "cancel-path");
263 if (value) {
264 tpm_pt->options->cancel_path = g_strdup(value);
265 tpm_pt->options->has_cancel_path = true;
266 }
267
268 value = qemu_opt_get(opts, "path");
269 if (value) {
270 tpm_pt->options->has_path = true;
271 tpm_pt->options->path = g_strdup(value);
272 }
273
274 tpm_pt->tpm_dev = value ? value : TPM_PASSTHROUGH_DEFAULT_DEVICE;
275 tpm_pt->tpm_fd = qemu_open_old(tpm_pt->tpm_dev, O_RDWR);
276 if (tpm_pt->tpm_fd < 0) {
277 error_report("Cannot access TPM device using '%s': %s",
278 tpm_pt->tpm_dev, strerror(errno));
279 return -1;
280 }
281
282 if (tpm_util_test_tpmdev(tpm_pt->tpm_fd, &tpm_pt->tpm_version)) {
283 error_report("'%s' is not a TPM device.",
284 tpm_pt->tpm_dev);
285 return -1;
286 }
287
288 tpm_pt->cancel_fd = tpm_passthrough_open_sysfs_cancel(tpm_pt);
289 if (tpm_pt->cancel_fd < 0) {
290 return -1;
291 }
292
293 return 0;
294 }
295
296 static TPMBackend *tpm_passthrough_create(QemuOpts *opts)
297 {
298 Object *obj = object_new(TYPE_TPM_PASSTHROUGH);
299
300 if (tpm_passthrough_handle_device_opts(TPM_PASSTHROUGH(obj), opts)) {
301 object_unref(obj);
302 return NULL;
303 }
304
305 return TPM_BACKEND(obj);
306 }
307
308 static int tpm_passthrough_startup_tpm(TPMBackend *tb, size_t buffersize)
309 {
310 TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(tb);
311
312 if (buffersize && buffersize < tpm_pt->tpm_buffersize) {
313 error_report("Requested buffer size of %zu is smaller than host TPM's "
314 "fixed buffer size of %zu",
315 buffersize, tpm_pt->tpm_buffersize);
316 return -1;
317 }
318
319 return 0;
320 }
321
322 static TpmTypeOptions *tpm_passthrough_get_tpm_options(TPMBackend *tb)
323 {
324 TpmTypeOptions *options = g_new0(TpmTypeOptions, 1);
325
326 options->type = TPM_TYPE_OPTIONS_KIND_PASSTHROUGH;
327 options->u.passthrough.data = QAPI_CLONE(TPMPassthroughOptions,
328 TPM_PASSTHROUGH(tb)->options);
329
330 return options;
331 }
332
333 static const QemuOptDesc tpm_passthrough_cmdline_opts[] = {
334 TPM_STANDARD_CMDLINE_OPTS,
335 {
336 .name = "cancel-path",
337 .type = QEMU_OPT_STRING,
338 .help = "Sysfs file entry for canceling TPM commands",
339 },
340 {
341 .name = "path",
342 .type = QEMU_OPT_STRING,
343 .help = "Path to TPM device on the host",
344 },
345 { /* end of list */ },
346 };
347
348 static void tpm_passthrough_inst_init(Object *obj)
349 {
350 TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(obj);
351
352 tpm_pt->options = g_new0(TPMPassthroughOptions, 1);
353 tpm_pt->tpm_fd = -1;
354 tpm_pt->cancel_fd = -1;
355 }
356
357 static void tpm_passthrough_inst_finalize(Object *obj)
358 {
359 TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(obj);
360
361 tpm_passthrough_cancel_cmd(TPM_BACKEND(obj));
362
363 if (tpm_pt->tpm_fd >= 0) {
364 qemu_close(tpm_pt->tpm_fd);
365 }
366 if (tpm_pt->cancel_fd >= 0) {
367 qemu_close(tpm_pt->cancel_fd);
368 }
369 qapi_free_TPMPassthroughOptions(tpm_pt->options);
370 }
371
372 static void tpm_passthrough_class_init(ObjectClass *klass, void *data)
373 {
374 TPMBackendClass *tbc = TPM_BACKEND_CLASS(klass);
375
376 tbc->type = TPM_TYPE_PASSTHROUGH;
377 tbc->opts = tpm_passthrough_cmdline_opts;
378 tbc->desc = "Passthrough TPM backend driver";
379 tbc->create = tpm_passthrough_create;
380 tbc->startup_tpm = tpm_passthrough_startup_tpm;
381 tbc->reset = tpm_passthrough_reset;
382 tbc->cancel_cmd = tpm_passthrough_cancel_cmd;
383 tbc->get_tpm_established_flag = tpm_passthrough_get_tpm_established_flag;
384 tbc->reset_tpm_established_flag =
385 tpm_passthrough_reset_tpm_established_flag;
386 tbc->get_tpm_version = tpm_passthrough_get_tpm_version;
387 tbc->get_buffer_size = tpm_passthrough_get_buffer_size;
388 tbc->get_tpm_options = tpm_passthrough_get_tpm_options;
389 tbc->handle_request = tpm_passthrough_handle_request;
390 }
391
392 static const TypeInfo tpm_passthrough_info = {
393 .name = TYPE_TPM_PASSTHROUGH,
394 .parent = TYPE_TPM_BACKEND,
395 .instance_size = sizeof(TPMPassthruState),
396 .class_init = tpm_passthrough_class_init,
397 .instance_init = tpm_passthrough_inst_init,
398 .instance_finalize = tpm_passthrough_inst_finalize,
399 };
400
401 static void tpm_passthrough_register(void)
402 {
403 type_register_static(&tpm_passthrough_info);
404 }
405
406 type_init(tpm_passthrough_register)