1 /* SPDX-License-Identifier: GPL-2.0 */
2
3 #ifndef __LINUX_TPM_EVENTLOG_H__
4 #define __LINUX_TPM_EVENTLOG_H__
5
6 #include <linux/tpm.h>
7
8 #define TCG_EVENT_NAME_LEN_MAX 255
9 #define MAX_TEXT_EVENT 1000 /* Max event string length */
10 #define ACPI_TCPA_SIG "TCPA" /* 0x41504354 /'TCPA' */
11
12 #define EFI_TCG2_EVENT_LOG_FORMAT_TCG_1_2 0x1
13 #define EFI_TCG2_EVENT_LOG_FORMAT_TCG_2 0x2
14
15 #ifdef CONFIG_PPC64
16 #define do_endian_conversion(x) be32_to_cpu(x)
17 #else
18 #define do_endian_conversion(x) x
19 #endif
20
21 enum bios_platform_class {
22 BIOS_CLIENT = 0x00,
23 BIOS_SERVER = 0x01,
24 };
25
26 struct tcpa_event {
27 u32 pcr_index;
28 u32 event_type;
29 u8 pcr_value[20]; /* SHA1 */
30 u32 event_size;
31 u8 event_data[];
32 };
33
34 enum tcpa_event_types {
35 PREBOOT = 0,
36 POST_CODE,
37 UNUSED,
38 NO_ACTION,
39 SEPARATOR,
40 ACTION,
41 EVENT_TAG,
42 SCRTM_CONTENTS,
43 SCRTM_VERSION,
44 CPU_MICROCODE,
45 PLATFORM_CONFIG_FLAGS,
46 TABLE_OF_DEVICES,
47 COMPACT_HASH,
48 IPL,
49 IPL_PARTITION_DATA,
50 NONHOST_CODE,
51 NONHOST_CONFIG,
52 NONHOST_INFO,
53 };
54
55 struct tcpa_pc_event {
56 u32 event_id;
57 u32 event_size;
58 u8 event_data[];
59 };
60
61 enum tcpa_pc_event_ids {
62 SMBIOS = 1,
63 BIS_CERT,
64 POST_BIOS_ROM,
65 ESCD,
66 CMOS,
67 NVRAM,
68 OPTION_ROM_EXEC,
69 OPTION_ROM_CONFIG,
70 OPTION_ROM_MICROCODE = 10,
71 S_CRTM_VERSION,
72 S_CRTM_CONTENTS,
73 POST_CONTENTS,
74 HOST_TABLE_OF_DEVICES,
75 };
76
77 /* http://www.trustedcomputinggroup.org/tcg-efi-protocol-specification/ */
78
79 struct tcg_efi_specid_event_algs {
80 u16 alg_id;
81 u16 digest_size;
82 } __packed;
83
84 #define TCG_SPECID_SIG "Spec ID Event03"
85
86 struct tcg_efi_specid_event_head {
87 u8 signature[16];
88 u32 platform_class;
89 u8 spec_version_minor;
90 u8 spec_version_major;
91 u8 spec_errata;
92 u8 uintnsize;
93 u32 num_algs;
94 struct tcg_efi_specid_event_algs digest_sizes[];
95 } __packed;
96
97 struct tcg_pcr_event {
98 u32 pcr_idx;
99 u32 event_type;
100 u8 digest[20];
101 u32 event_size;
102 u8 event[];
103 } __packed;
104
105 struct tcg_event_field {
106 u32 event_size;
107 u8 event[];
108 } __packed;
109
110 struct tcg_pcr_event2_head {
111 u32 pcr_idx;
112 u32 event_type;
113 u32 count;
114 struct tpm_digest digests[];
115 } __packed;
116
117 struct tcg_algorithm_size {
118 u16 algorithm_id;
119 u16 algorithm_size;
120 };
121
122 struct tcg_algorithm_info {
123 u8 signature[16];
124 u32 platform_class;
125 u8 spec_version_minor;
126 u8 spec_version_major;
127 u8 spec_errata;
128 u8 uintn_size;
129 u32 number_of_algorithms;
130 struct tcg_algorithm_size digest_sizes[];
131 };
132
133 #ifndef TPM_MEMREMAP
134 #define TPM_MEMREMAP(start, size) NULL
135 #endif
136
137 #ifndef TPM_MEMUNMAP
138 #define TPM_MEMUNMAP(start, size) do{} while(0)
139 #endif
140
141 /**
142 * __calc_tpm2_event_size - calculate the size of a TPM2 event log entry
143 * @event: Pointer to the event whose size should be calculated
144 * @event_header: Pointer to the initial event containing the digest lengths
145 * @do_mapping: Whether or not the event needs to be mapped
146 *
147 * The TPM2 event log format can contain multiple digests corresponding to
148 * separate PCR banks, and also contains a variable length of the data that
149 * was measured. This requires knowledge of how long each digest type is,
150 * and this information is contained within the first event in the log.
151 *
152 * We calculate the length by examining the number of events, and then looking
153 * at each event in turn to determine how much space is used for events in
154 * total. Once we've done this we know the offset of the data length field,
155 * and can calculate the total size of the event.
156 *
157 * Return: size of the event on success, 0 on failure
158 */
159
__calc_tpm2_event_size(struct tcg_pcr_event2_head * event,struct tcg_pcr_event * event_header,bool do_mapping)160 static __always_inline int __calc_tpm2_event_size(struct tcg_pcr_event2_head *event,
161 struct tcg_pcr_event *event_header,
162 bool do_mapping)
163 {
164 struct tcg_efi_specid_event_head *efispecid;
165 struct tcg_event_field *event_field;
166 void *mapping = NULL;
167 int mapping_size;
168 void *marker;
169 void *marker_start;
170 u32 halg_size;
171 size_t size;
172 u16 halg;
173 int i;
174 int j;
175 u32 count, event_type;
176 const u8 zero_digest[sizeof(event_header->digest)] = {0};
177
178 marker = event;
179 marker_start = marker;
180 marker = marker + sizeof(event->pcr_idx) + sizeof(event->event_type)
181 + sizeof(event->count);
182
183 /* Map the event header */
184 if (do_mapping) {
185 mapping_size = marker - marker_start;
186 mapping = TPM_MEMREMAP((unsigned long)marker_start,
187 mapping_size);
188 if (!mapping) {
189 size = 0;
190 goto out;
191 }
192 } else {
193 mapping = marker_start;
194 }
195
196 event = (struct tcg_pcr_event2_head *)mapping;
197 /*
198 * The loop below will unmap these fields if the log is larger than
199 * one page, so save them here for reference:
200 */
201 count = READ_ONCE(event->count);
202 event_type = READ_ONCE(event->event_type);
203
204 /* Verify that it's the log header */
205 if (event_header->pcr_idx != 0 ||
206 event_header->event_type != NO_ACTION ||
207 memcmp(event_header->digest, zero_digest, sizeof(zero_digest))) {
208 size = 0;
209 goto out;
210 }
211
212 efispecid = (struct tcg_efi_specid_event_head *)event_header->event;
213
214 /*
215 * Perform validation of the event in order to identify malformed
216 * events. This function may be asked to parse arbitrary byte sequences
217 * immediately following a valid event log. The caller expects this
218 * function to recognize that the byte sequence is not a valid event
219 * and to return an event size of 0.
220 */
221 if (memcmp(efispecid->signature, TCG_SPECID_SIG,
222 sizeof(TCG_SPECID_SIG)) ||
223 !efispecid->num_algs || count != efispecid->num_algs) {
224 size = 0;
225 goto out;
226 }
227
228 for (i = 0; i < count; i++) {
229 halg_size = sizeof(event->digests[i].alg_id);
230
231 /* Map the digest's algorithm identifier */
232 if (do_mapping) {
233 TPM_MEMUNMAP(mapping, mapping_size);
234 mapping_size = halg_size;
235 mapping = TPM_MEMREMAP((unsigned long)marker,
236 mapping_size);
237 if (!mapping) {
238 size = 0;
239 goto out;
240 }
241 } else {
242 mapping = marker;
243 }
244
245 memcpy(&halg, mapping, halg_size);
246 marker = marker + halg_size;
247
248 for (j = 0; j < efispecid->num_algs; j++) {
249 if (halg == efispecid->digest_sizes[j].alg_id) {
250 marker +=
251 efispecid->digest_sizes[j].digest_size;
252 break;
253 }
254 }
255 /* Algorithm without known length. Such event is unparseable. */
256 if (j == efispecid->num_algs) {
257 size = 0;
258 goto out;
259 }
260 }
261
262 /*
263 * Map the event size - we don't read from the event itself, so
264 * we don't need to map it
265 */
266 if (do_mapping) {
267 TPM_MEMUNMAP(mapping, mapping_size);
268 mapping_size += sizeof(event_field->event_size);
269 mapping = TPM_MEMREMAP((unsigned long)marker,
270 mapping_size);
271 if (!mapping) {
272 size = 0;
273 goto out;
274 }
275 } else {
276 mapping = marker;
277 }
278
279 event_field = (struct tcg_event_field *)mapping;
280
281 marker = marker + sizeof(event_field->event_size)
282 + event_field->event_size;
283 size = marker - marker_start;
284
285 if (event_type == 0 && event_field->event_size == 0)
286 size = 0;
287
288 out:
289 if (do_mapping)
290 TPM_MEMUNMAP(mapping, mapping_size);
291 return size;
292 }
293
294 #endif
295
