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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 "tpm_int.h"
32#include "hw/hw.h"
33#include "qapi/clone-visitor.h"
34#include "qapi/qapi-visit-tpm.h"
35#include "tpm_util.h"
36#include "trace.h"
37
38#define TYPE_TPM_PASSTHROUGH "tpm-passthrough"
39#define TPM_PASSTHROUGH(obj) \
40 OBJECT_CHECK(TPMPassthruState, (obj), TYPE_TPM_PASSTHROUGH)
41
42
43struct TPMPassthruState {
44 TPMBackend parent;
45
46 TPMPassthroughOptions *options;
47 const char *tpm_dev;
48 int tpm_fd;
49 bool tpm_executing;
50 bool tpm_op_canceled;
51 int cancel_fd;
52
53 TPMVersion tpm_version;
54 size_t tpm_buffersize;
55};
56
57typedef struct TPMPassthruState TPMPassthruState;
58
59#define TPM_PASSTHROUGH_DEFAULT_DEVICE "/dev/tpm0"
60
61
62
63static void tpm_passthrough_cancel_cmd(TPMBackend *tb);
64
65static 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
79static 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
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
122err_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
130static 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
142static void tpm_passthrough_reset(TPMBackend *tb)
143{
144 trace_tpm_passthrough_reset();
145
146 tpm_passthrough_cancel_cmd(tb);
147}
148
149static bool tpm_passthrough_get_tpm_established_flag(TPMBackend *tb)
150{
151 return false;
152}
153
154static int tpm_passthrough_reset_tpm_established_flag(TPMBackend *tb,
155 uint8_t locty)
156{
157
158 return 0;
159}
160
161static void tpm_passthrough_cancel_cmd(TPMBackend *tb)
162{
163 TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(tb);
164 int n;
165
166
167
168
169
170
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
187static 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
194static 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
209
210
211
212
213
214static 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(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(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(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
257static int
258tpm_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(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
296static 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
308static 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
322static 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
333static 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 { },
346};
347
348static 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
357static 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
372static 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
392static 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
401static void tpm_passthrough_register(void)
402{
403 type_register_static(&tpm_passthrough_info);
404}
405
406type_init(tpm_passthrough_register)
407