Merge tag 'pull-ppc-20211129' of https://github.com/legoater/qemu into staging
[qemu.git] / backends / tpm / tpm_util.c
1 /*
2 * TPM utility functions
3 *
4 * Copyright (c) 2010 - 2015 IBM Corporation
5 * Authors:
6 * Stefan Berger <stefanb@us.ibm.com>
7 *
8 * This library is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU Lesser General Public
10 * License as published by the Free Software Foundation; either
11 * version 2.1 of the License, or (at your option) any later version.
12 *
13 * This library is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * Lesser General Public License for more details.
17 *
18 * You should have received a copy of the GNU Lesser General Public
19 * License along with this library; if not, see <http://www.gnu.org/licenses/>
20 */
21
22 #include "qemu/osdep.h"
23 #include "qemu/error-report.h"
24 #include "qapi/error.h"
25 #include "qapi/visitor.h"
26 #include "tpm_int.h"
27 #include "exec/memory.h"
28 #include "hw/qdev-properties.h"
29 #include "sysemu/tpm_backend.h"
30 #include "sysemu/tpm_util.h"
31 #include "trace.h"
32
33 /* tpm backend property */
34
35 static void get_tpm(Object *obj, Visitor *v, const char *name, void *opaque,
36 Error **errp)
37 {
38 TPMBackend **be = object_field_prop_ptr(obj, opaque);
39 char *p;
40
41 p = g_strdup(*be ? (*be)->id : "");
42 visit_type_str(v, name, &p, errp);
43 g_free(p);
44 }
45
46 static void set_tpm(Object *obj, Visitor *v, const char *name, void *opaque,
47 Error **errp)
48 {
49 Property *prop = opaque;
50 TPMBackend *s, **be = object_field_prop_ptr(obj, prop);
51 char *str;
52
53 if (!visit_type_str(v, name, &str, errp)) {
54 return;
55 }
56
57 s = qemu_find_tpm_be(str);
58 if (s == NULL) {
59 error_setg(errp, "Property '%s.%s' can't find value '%s'",
60 object_get_typename(obj), name, str);
61 } else if (tpm_backend_init(s, TPM_IF(obj), errp) == 0) {
62 *be = s; /* weak reference, avoid cyclic ref */
63 }
64 g_free(str);
65 }
66
67 static void release_tpm(Object *obj, const char *name, void *opaque)
68 {
69 Property *prop = opaque;
70 TPMBackend **be = object_field_prop_ptr(obj, prop);
71
72 if (*be) {
73 tpm_backend_reset(*be);
74 }
75 }
76
77 const PropertyInfo qdev_prop_tpm = {
78 .name = "str",
79 .description = "ID of a tpm to use as a backend",
80 .get = get_tpm,
81 .set = set_tpm,
82 .release = release_tpm,
83 };
84
85 /*
86 * Write an error message in the given output buffer.
87 */
88 void tpm_util_write_fatal_error_response(uint8_t *out, uint32_t out_len)
89 {
90 if (out_len >= sizeof(struct tpm_resp_hdr)) {
91 tpm_cmd_set_tag(out, TPM_TAG_RSP_COMMAND);
92 tpm_cmd_set_size(out, sizeof(struct tpm_resp_hdr));
93 tpm_cmd_set_error(out, TPM_FAIL);
94 }
95 }
96
97 bool tpm_util_is_selftest(const uint8_t *in, uint32_t in_len)
98 {
99 if (in_len >= sizeof(struct tpm_req_hdr)) {
100 return tpm_cmd_get_ordinal(in) == TPM_ORD_ContinueSelfTest;
101 }
102
103 return false;
104 }
105
106 /*
107 * Send request to a TPM device. We expect a response within one second.
108 */
109 static int tpm_util_request(int fd,
110 const void *request,
111 size_t requestlen,
112 void *response,
113 size_t responselen)
114 {
115 fd_set readfds;
116 int n;
117 struct timeval tv = {
118 .tv_sec = 1,
119 .tv_usec = 0,
120 };
121
122 n = write(fd, request, requestlen);
123 if (n < 0) {
124 return -errno;
125 }
126 if (n != requestlen) {
127 return -EFAULT;
128 }
129
130 FD_ZERO(&readfds);
131 FD_SET(fd, &readfds);
132
133 /* wait for a second */
134 n = select(fd + 1, &readfds, NULL, NULL, &tv);
135 if (n != 1) {
136 return -errno;
137 }
138
139 n = read(fd, response, responselen);
140 if (n < sizeof(struct tpm_resp_hdr)) {
141 return -EFAULT;
142 }
143
144 /* check the header */
145 if (tpm_cmd_get_size(response) != n) {
146 return -EMSGSIZE;
147 }
148
149 return 0;
150 }
151
152 /*
153 * A basic test of a TPM device. We expect a well formatted response header
154 * (error response is fine).
155 */
156 static int tpm_util_test(int fd,
157 const void *request,
158 size_t requestlen,
159 uint16_t *return_tag)
160 {
161 char buf[1024];
162 ssize_t ret;
163
164 ret = tpm_util_request(fd, request, requestlen,
165 buf, sizeof(buf));
166 if (ret < 0) {
167 return ret;
168 }
169
170 *return_tag = tpm_cmd_get_tag(buf);
171
172 return 0;
173 }
174
175 /*
176 * Probe for the TPM device in the back
177 * Returns 0 on success with the version of the probed TPM set, 1 on failure.
178 */
179 int tpm_util_test_tpmdev(int tpm_fd, TPMVersion *tpm_version)
180 {
181 /*
182 * Sending a TPM1.2 command to a TPM2 should return a TPM1.2
183 * header (tag = 0xc4) and error code (TPM_BADTAG = 0x1e)
184 *
185 * Sending a TPM2 command to a TPM 2 will give a TPM 2 tag in the
186 * header.
187 * Sending a TPM2 command to a TPM 1.2 will give a TPM 1.2 tag
188 * in the header and an error code.
189 */
190 const struct tpm_req_hdr test_req = {
191 .tag = cpu_to_be16(TPM_TAG_RQU_COMMAND),
192 .len = cpu_to_be32(sizeof(test_req)),
193 .ordinal = cpu_to_be32(TPM_ORD_GetTicks),
194 };
195
196 const struct tpm_req_hdr test_req_tpm2 = {
197 .tag = cpu_to_be16(TPM2_ST_NO_SESSIONS),
198 .len = cpu_to_be32(sizeof(test_req_tpm2)),
199 .ordinal = cpu_to_be32(TPM2_CC_ReadClock),
200 };
201 uint16_t return_tag;
202 int ret;
203
204 /* Send TPM 2 command */
205 ret = tpm_util_test(tpm_fd, &test_req_tpm2,
206 sizeof(test_req_tpm2), &return_tag);
207 /* TPM 2 would respond with a tag of TPM2_ST_NO_SESSIONS */
208 if (!ret && return_tag == TPM2_ST_NO_SESSIONS) {
209 *tpm_version = TPM_VERSION_2_0;
210 return 0;
211 }
212
213 /* Send TPM 1.2 command */
214 ret = tpm_util_test(tpm_fd, &test_req,
215 sizeof(test_req), &return_tag);
216 if (!ret && return_tag == TPM_TAG_RSP_COMMAND) {
217 *tpm_version = TPM_VERSION_1_2;
218 /* this is a TPM 1.2 */
219 return 0;
220 }
221
222 *tpm_version = TPM_VERSION_UNSPEC;
223
224 return 1;
225 }
226
227 int tpm_util_get_buffer_size(int tpm_fd, TPMVersion tpm_version,
228 size_t *buffersize)
229 {
230 int ret;
231
232 switch (tpm_version) {
233 case TPM_VERSION_1_2: {
234 const struct tpm_req_get_buffer_size {
235 struct tpm_req_hdr hdr;
236 uint32_t capability;
237 uint32_t len;
238 uint32_t subcap;
239 } QEMU_PACKED tpm_get_buffer_size = {
240 .hdr = {
241 .tag = cpu_to_be16(TPM_TAG_RQU_COMMAND),
242 .len = cpu_to_be32(sizeof(tpm_get_buffer_size)),
243 .ordinal = cpu_to_be32(TPM_ORD_GetCapability),
244 },
245 .capability = cpu_to_be32(TPM_CAP_PROPERTY),
246 .len = cpu_to_be32(sizeof(uint32_t)),
247 .subcap = cpu_to_be32(TPM_CAP_PROP_INPUT_BUFFER),
248 };
249 struct tpm_resp_get_buffer_size {
250 struct tpm_resp_hdr hdr;
251 uint32_t len;
252 uint32_t buffersize;
253 } QEMU_PACKED tpm_resp;
254
255 ret = tpm_util_request(tpm_fd, &tpm_get_buffer_size,
256 sizeof(tpm_get_buffer_size),
257 &tpm_resp, sizeof(tpm_resp));
258 if (ret < 0) {
259 return ret;
260 }
261
262 if (be32_to_cpu(tpm_resp.hdr.len) != sizeof(tpm_resp) ||
263 be32_to_cpu(tpm_resp.len) != sizeof(uint32_t)) {
264 trace_tpm_util_get_buffer_size_hdr_len(
265 be32_to_cpu(tpm_resp.hdr.len),
266 sizeof(tpm_resp));
267 trace_tpm_util_get_buffer_size_len(be32_to_cpu(tpm_resp.len),
268 sizeof(uint32_t));
269 error_report("tpm_util: Got unexpected response to "
270 "TPM_GetCapability; errcode: 0x%x",
271 be32_to_cpu(tpm_resp.hdr.errcode));
272 return -EFAULT;
273 }
274 *buffersize = be32_to_cpu(tpm_resp.buffersize);
275 break;
276 }
277 case TPM_VERSION_2_0: {
278 const struct tpm2_req_get_buffer_size {
279 struct tpm_req_hdr hdr;
280 uint32_t capability;
281 uint32_t property;
282 uint32_t count;
283 } QEMU_PACKED tpm2_get_buffer_size = {
284 .hdr = {
285 .tag = cpu_to_be16(TPM2_ST_NO_SESSIONS),
286 .len = cpu_to_be32(sizeof(tpm2_get_buffer_size)),
287 .ordinal = cpu_to_be32(TPM2_CC_GetCapability),
288 },
289 .capability = cpu_to_be32(TPM2_CAP_TPM_PROPERTIES),
290 .property = cpu_to_be32(TPM2_PT_MAX_COMMAND_SIZE),
291 .count = cpu_to_be32(2), /* also get TPM2_PT_MAX_RESPONSE_SIZE */
292 };
293 struct tpm2_resp_get_buffer_size {
294 struct tpm_resp_hdr hdr;
295 uint8_t more;
296 uint32_t capability;
297 uint32_t count;
298 uint32_t property1;
299 uint32_t value1;
300 uint32_t property2;
301 uint32_t value2;
302 } QEMU_PACKED tpm2_resp;
303
304 ret = tpm_util_request(tpm_fd, &tpm2_get_buffer_size,
305 sizeof(tpm2_get_buffer_size),
306 &tpm2_resp, sizeof(tpm2_resp));
307 if (ret < 0) {
308 return ret;
309 }
310
311 if (be32_to_cpu(tpm2_resp.hdr.len) != sizeof(tpm2_resp) ||
312 be32_to_cpu(tpm2_resp.count) != 2) {
313 trace_tpm_util_get_buffer_size_hdr_len2(
314 be32_to_cpu(tpm2_resp.hdr.len),
315 sizeof(tpm2_resp));
316 trace_tpm_util_get_buffer_size_len2(
317 be32_to_cpu(tpm2_resp.count), 2);
318 error_report("tpm_util: Got unexpected response to "
319 "TPM2_GetCapability; errcode: 0x%x",
320 be32_to_cpu(tpm2_resp.hdr.errcode));
321 return -EFAULT;
322 }
323 *buffersize = MAX(be32_to_cpu(tpm2_resp.value1),
324 be32_to_cpu(tpm2_resp.value2));
325 break;
326 }
327 case TPM_VERSION_UNSPEC:
328 return -EFAULT;
329 }
330
331 trace_tpm_util_get_buffer_size(*buffersize);
332
333 return 0;
334 }
335
336 void tpm_sized_buffer_reset(TPMSizedBuffer *tsb)
337 {
338 g_free(tsb->buffer);
339 tsb->buffer = NULL;
340 tsb->size = 0;
341 }
342
343 void tpm_util_show_buffer(const unsigned char *buffer,
344 size_t buffer_size, const char *string)
345 {
346 size_t len, i;
347 char *line_buffer, *p;
348
349 if (!trace_event_get_state_backends(TRACE_TPM_UTIL_SHOW_BUFFER)) {
350 return;
351 }
352 len = MIN(tpm_cmd_get_size(buffer), buffer_size);
353
354 /*
355 * allocate enough room for 3 chars per buffer entry plus a
356 * newline after every 16 chars and a final null terminator.
357 */
358 line_buffer = g_malloc(len * 3 + (len / 16) + 1);
359
360 for (i = 0, p = line_buffer; i < len; i++) {
361 if (i && !(i % 16)) {
362 p += sprintf(p, "\n");
363 }
364 p += sprintf(p, "%.2X ", buffer[i]);
365 }
366 trace_tpm_util_show_buffer(string, len, line_buffer);
367
368 g_free(line_buffer);
369 }