Merge tag 'pull-ppc-20211129' of https://github.com/legoater/qemu into staging
[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 2.1 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 OBJECT_DECLARE_SIMPLE_TYPE(TPMPassthruState, TPM_PASSTHROUGH)
40
41 /* data structures */
42 struct TPMPassthruState {
43 TPMBackend parent;
44
45 TPMPassthroughOptions *options;
46 const char *tpm_dev;
47 int tpm_fd;
48 bool tpm_executing;
49 bool tpm_op_canceled;
50 int cancel_fd;
51
52 TPMVersion tpm_version;
53 size_t tpm_buffersize;
54 };
55
56
57 #define TPM_PASSTHROUGH_DEFAULT_DEVICE "/dev/tpm0"
58
59 /* functions */
60
61 static void tpm_passthrough_cancel_cmd(TPMBackend *tb);
62
63 static int tpm_passthrough_unix_read(int fd, uint8_t *buf, uint32_t len)
64 {
65 int ret;
66 reread:
67 ret = read(fd, buf, len);
68 if (ret < 0) {
69 if (errno != EINTR && errno != EAGAIN) {
70 return -1;
71 }
72 goto reread;
73 }
74 return ret;
75 }
76
77 static void tpm_passthrough_unix_tx_bufs(TPMPassthruState *tpm_pt,
78 const uint8_t *in, uint32_t in_len,
79 uint8_t *out, uint32_t out_len,
80 bool *selftest_done, Error **errp)
81 {
82 ssize_t ret;
83 bool is_selftest;
84
85 /* FIXME: protect shared variables or use other sync mechanism */
86 tpm_pt->tpm_op_canceled = false;
87 tpm_pt->tpm_executing = true;
88 *selftest_done = false;
89
90 is_selftest = tpm_util_is_selftest(in, in_len);
91
92 ret = qemu_write_full(tpm_pt->tpm_fd, in, in_len);
93 if (ret != in_len) {
94 if (!tpm_pt->tpm_op_canceled || errno != ECANCELED) {
95 error_setg_errno(errp, errno, "tpm_passthrough: error while "
96 "transmitting data to TPM");
97 }
98 goto err_exit;
99 }
100
101 tpm_pt->tpm_executing = false;
102
103 ret = tpm_passthrough_unix_read(tpm_pt->tpm_fd, out, out_len);
104 if (ret < 0) {
105 if (!tpm_pt->tpm_op_canceled || errno != ECANCELED) {
106 error_setg_errno(errp, errno, "tpm_passthrough: error while "
107 "reading data from TPM");
108 }
109 } else if (ret < sizeof(struct tpm_resp_hdr) ||
110 tpm_cmd_get_size(out) != ret) {
111 ret = -1;
112 error_setg_errno(errp, errno, "tpm_passthrough: received invalid "
113 "response packet from TPM");
114 }
115
116 if (is_selftest && (ret >= sizeof(struct tpm_resp_hdr))) {
117 *selftest_done = tpm_cmd_get_errcode(out) == 0;
118 }
119
120 err_exit:
121 if (ret < 0) {
122 tpm_util_write_fatal_error_response(out, out_len);
123 }
124
125 tpm_pt->tpm_executing = false;
126 }
127
128 static void tpm_passthrough_handle_request(TPMBackend *tb, TPMBackendCmd *cmd,
129 Error **errp)
130 {
131 TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(tb);
132
133 trace_tpm_passthrough_handle_request(cmd);
134
135 tpm_passthrough_unix_tx_bufs(tpm_pt, cmd->in, cmd->in_len,
136 cmd->out, cmd->out_len, &cmd->selftest_done,
137 errp);
138 }
139
140 static void tpm_passthrough_reset(TPMBackend *tb)
141 {
142 trace_tpm_passthrough_reset();
143
144 tpm_passthrough_cancel_cmd(tb);
145 }
146
147 static bool tpm_passthrough_get_tpm_established_flag(TPMBackend *tb)
148 {
149 return false;
150 }
151
152 static int tpm_passthrough_reset_tpm_established_flag(TPMBackend *tb,
153 uint8_t locty)
154 {
155 /* only a TPM 2.0 will support this */
156 return 0;
157 }
158
159 static void tpm_passthrough_cancel_cmd(TPMBackend *tb)
160 {
161 TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(tb);
162 int n;
163
164 /*
165 * As of Linux 3.7 the tpm_tis driver does not properly cancel
166 * commands on all TPM manufacturers' TPMs.
167 * Only cancel if we're busy so we don't cancel someone else's
168 * command, e.g., a command executed on the host.
169 */
170 if (tpm_pt->tpm_executing) {
171 if (tpm_pt->cancel_fd >= 0) {
172 tpm_pt->tpm_op_canceled = true;
173 n = write(tpm_pt->cancel_fd, "-", 1);
174 if (n != 1) {
175 error_report("Canceling TPM command failed: %s",
176 strerror(errno));
177 }
178 } else {
179 error_report("Cannot cancel TPM command due to missing "
180 "TPM sysfs cancel entry");
181 }
182 }
183 }
184
185 static TPMVersion tpm_passthrough_get_tpm_version(TPMBackend *tb)
186 {
187 TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(tb);
188
189 return tpm_pt->tpm_version;
190 }
191
192 static size_t tpm_passthrough_get_buffer_size(TPMBackend *tb)
193 {
194 TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(tb);
195 int ret;
196
197 ret = tpm_util_get_buffer_size(tpm_pt->tpm_fd, tpm_pt->tpm_version,
198 &tpm_pt->tpm_buffersize);
199 if (ret < 0) {
200 tpm_pt->tpm_buffersize = 4096;
201 }
202 return tpm_pt->tpm_buffersize;
203 }
204
205 /*
206 * Unless path or file descriptor set has been provided by user,
207 * determine the sysfs cancel file following kernel documentation
208 * in Documentation/ABI/stable/sysfs-class-tpm.
209 * From /dev/tpm0 create /sys/class/tpm/tpm0/device/cancel
210 * before 4.0: /sys/class/misc/tpm0/device/cancel
211 */
212 static int tpm_passthrough_open_sysfs_cancel(TPMPassthruState *tpm_pt)
213 {
214 int fd = -1;
215 char *dev;
216 char path[PATH_MAX];
217
218 if (tpm_pt->options->cancel_path) {
219 fd = qemu_open_old(tpm_pt->options->cancel_path, O_WRONLY);
220 if (fd < 0) {
221 error_report("tpm_passthrough: Could not open TPM cancel path: %s",
222 strerror(errno));
223 }
224 return fd;
225 }
226
227 dev = strrchr(tpm_pt->tpm_dev, '/');
228 if (!dev) {
229 error_report("tpm_passthrough: Bad TPM device path %s",
230 tpm_pt->tpm_dev);
231 return -1;
232 }
233
234 dev++;
235 if (snprintf(path, sizeof(path), "/sys/class/tpm/%s/device/cancel",
236 dev) < sizeof(path)) {
237 fd = qemu_open_old(path, O_WRONLY);
238 if (fd < 0) {
239 if (snprintf(path, sizeof(path), "/sys/class/misc/%s/device/cancel",
240 dev) < sizeof(path)) {
241 fd = qemu_open_old(path, O_WRONLY);
242 }
243 }
244 }
245
246 if (fd < 0) {
247 error_report("tpm_passthrough: Could not guess TPM cancel path");
248 } else {
249 tpm_pt->options->cancel_path = g_strdup(path);
250 }
251
252 return fd;
253 }
254
255 static int
256 tpm_passthrough_handle_device_opts(TPMPassthruState *tpm_pt, QemuOpts *opts)
257 {
258 const char *value;
259
260 value = qemu_opt_get(opts, "cancel-path");
261 if (value) {
262 tpm_pt->options->cancel_path = g_strdup(value);
263 tpm_pt->options->has_cancel_path = true;
264 }
265
266 value = qemu_opt_get(opts, "path");
267 if (value) {
268 tpm_pt->options->has_path = true;
269 tpm_pt->options->path = g_strdup(value);
270 }
271
272 tpm_pt->tpm_dev = value ? value : TPM_PASSTHROUGH_DEFAULT_DEVICE;
273 tpm_pt->tpm_fd = qemu_open_old(tpm_pt->tpm_dev, O_RDWR);
274 if (tpm_pt->tpm_fd < 0) {
275 error_report("Cannot access TPM device using '%s': %s",
276 tpm_pt->tpm_dev, strerror(errno));
277 return -1;
278 }
279
280 if (tpm_util_test_tpmdev(tpm_pt->tpm_fd, &tpm_pt->tpm_version)) {
281 error_report("'%s' is not a TPM device.",
282 tpm_pt->tpm_dev);
283 return -1;
284 }
285
286 tpm_pt->cancel_fd = tpm_passthrough_open_sysfs_cancel(tpm_pt);
287 if (tpm_pt->cancel_fd < 0) {
288 return -1;
289 }
290
291 return 0;
292 }
293
294 static TPMBackend *tpm_passthrough_create(QemuOpts *opts)
295 {
296 Object *obj = object_new(TYPE_TPM_PASSTHROUGH);
297
298 if (tpm_passthrough_handle_device_opts(TPM_PASSTHROUGH(obj), opts)) {
299 object_unref(obj);
300 return NULL;
301 }
302
303 return TPM_BACKEND(obj);
304 }
305
306 static int tpm_passthrough_startup_tpm(TPMBackend *tb, size_t buffersize)
307 {
308 TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(tb);
309
310 if (buffersize && buffersize < tpm_pt->tpm_buffersize) {
311 error_report("Requested buffer size of %zu is smaller than host TPM's "
312 "fixed buffer size of %zu",
313 buffersize, tpm_pt->tpm_buffersize);
314 return -1;
315 }
316
317 return 0;
318 }
319
320 static TpmTypeOptions *tpm_passthrough_get_tpm_options(TPMBackend *tb)
321 {
322 TpmTypeOptions *options = g_new0(TpmTypeOptions, 1);
323
324 options->type = TPM_TYPE_OPTIONS_KIND_PASSTHROUGH;
325 options->u.passthrough.data = QAPI_CLONE(TPMPassthroughOptions,
326 TPM_PASSTHROUGH(tb)->options);
327
328 return options;
329 }
330
331 static const QemuOptDesc tpm_passthrough_cmdline_opts[] = {
332 TPM_STANDARD_CMDLINE_OPTS,
333 {
334 .name = "cancel-path",
335 .type = QEMU_OPT_STRING,
336 .help = "Sysfs file entry for canceling TPM commands",
337 },
338 {
339 .name = "path",
340 .type = QEMU_OPT_STRING,
341 .help = "Path to TPM device on the host",
342 },
343 { /* end of list */ },
344 };
345
346 static void tpm_passthrough_inst_init(Object *obj)
347 {
348 TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(obj);
349
350 tpm_pt->options = g_new0(TPMPassthroughOptions, 1);
351 tpm_pt->tpm_fd = -1;
352 tpm_pt->cancel_fd = -1;
353 }
354
355 static void tpm_passthrough_inst_finalize(Object *obj)
356 {
357 TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(obj);
358
359 tpm_passthrough_cancel_cmd(TPM_BACKEND(obj));
360
361 if (tpm_pt->tpm_fd >= 0) {
362 qemu_close(tpm_pt->tpm_fd);
363 }
364 if (tpm_pt->cancel_fd >= 0) {
365 qemu_close(tpm_pt->cancel_fd);
366 }
367 qapi_free_TPMPassthroughOptions(tpm_pt->options);
368 }
369
370 static void tpm_passthrough_class_init(ObjectClass *klass, void *data)
371 {
372 TPMBackendClass *tbc = TPM_BACKEND_CLASS(klass);
373
374 tbc->type = TPM_TYPE_PASSTHROUGH;
375 tbc->opts = tpm_passthrough_cmdline_opts;
376 tbc->desc = "Passthrough TPM backend driver";
377 tbc->create = tpm_passthrough_create;
378 tbc->startup_tpm = tpm_passthrough_startup_tpm;
379 tbc->reset = tpm_passthrough_reset;
380 tbc->cancel_cmd = tpm_passthrough_cancel_cmd;
381 tbc->get_tpm_established_flag = tpm_passthrough_get_tpm_established_flag;
382 tbc->reset_tpm_established_flag =
383 tpm_passthrough_reset_tpm_established_flag;
384 tbc->get_tpm_version = tpm_passthrough_get_tpm_version;
385 tbc->get_buffer_size = tpm_passthrough_get_buffer_size;
386 tbc->get_tpm_options = tpm_passthrough_get_tpm_options;
387 tbc->handle_request = tpm_passthrough_handle_request;
388 }
389
390 static const TypeInfo tpm_passthrough_info = {
391 .name = TYPE_TPM_PASSTHROUGH,
392 .parent = TYPE_TPM_BACKEND,
393 .instance_size = sizeof(TPMPassthruState),
394 .class_init = tpm_passthrough_class_init,
395 .instance_init = tpm_passthrough_inst_init,
396 .instance_finalize = tpm_passthrough_inst_finalize,
397 };
398
399 static void tpm_passthrough_register(void)
400 {
401 type_register_static(&tpm_passthrough_info);
402 }
403
404 type_init(tpm_passthrough_register)