1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Copyright (C) 2016 IBM Corporation
4 *
5 * Authors:
6 * Nayna Jain <nayna@linux.vnet.ibm.com>
7 *
8 * Access to TPM 2.0 event log as written by Firmware.
9 * It assumes that writer of event log has followed TCG Specification
10 * for Family "2.0" and written the event data in little endian.
11 * With that, it doesn't need any endian conversion for structure
12 * content.
13 */
14
15 #include <linux/seq_file.h>
16 #include <linux/fs.h>
17 #include <linux/security.h>
18 #include <linux/module.h>
19 #include <linux/slab.h>
20 #include <linux/tpm_eventlog.h>
21
22 #include "../tpm.h"
23 #include "common.h"
24
25 /*
26 * calc_tpm2_event_size() - calculate the event size, where event
27 * is an entry in the TPM 2.0 event log. The event is of type Crypto
28 * Agile Log Entry Format as defined in TCG EFI Protocol Specification
29 * Family "2.0".
30
31 * @event: event whose size is to be calculated.
32 * @event_header: the first event in the event log.
33 *
34 * Returns size of the event. If it is an invalid event, returns 0.
35 */
calc_tpm2_event_size(struct tcg_pcr_event2_head * event,struct tcg_pcr_event * event_header)36 static size_t calc_tpm2_event_size(struct tcg_pcr_event2_head *event,
37 struct tcg_pcr_event *event_header)
38 {
39 return __calc_tpm2_event_size(event, event_header, false);
40 }
41
tpm2_bios_measurements_start(struct seq_file * m,loff_t * pos)42 static void *tpm2_bios_measurements_start(struct seq_file *m, loff_t *pos)
43 {
44 struct tpm_chip *chip = m->private;
45 struct tpm_bios_log *log = &chip->log;
46 void *addr = log->bios_event_log;
47 void *limit = log->bios_event_log_end;
48 struct tcg_pcr_event *event_header;
49 struct tcg_pcr_event2_head *event;
50 size_t size;
51 int i;
52
53 event_header = addr;
54 size = sizeof(struct tcg_pcr_event) - sizeof(event_header->event)
55 + event_header->event_size;
56
57 if (*pos == 0) {
58 if (addr + size < limit) {
59 if ((event_header->event_type == 0) &&
60 (event_header->event_size == 0))
61 return NULL;
62 return SEQ_START_TOKEN;
63 }
64 }
65
66 if (*pos > 0) {
67 addr += size;
68 event = addr;
69 size = calc_tpm2_event_size(event, event_header);
70 if ((addr + size >= limit) || (size == 0))
71 return NULL;
72 }
73
74 for (i = 0; i < (*pos - 1); i++) {
75 event = addr;
76 size = calc_tpm2_event_size(event, event_header);
77
78 if ((addr + size >= limit) || (size == 0))
79 return NULL;
80 addr += size;
81 }
82
83 return addr;
84 }
85
tpm2_bios_measurements_next(struct seq_file * m,void * v,loff_t * pos)86 static void *tpm2_bios_measurements_next(struct seq_file *m, void *v,
87 loff_t *pos)
88 {
89 struct tcg_pcr_event *event_header;
90 struct tcg_pcr_event2_head *event;
91 struct tpm_chip *chip = m->private;
92 struct tpm_bios_log *log = &chip->log;
93 void *limit = log->bios_event_log_end;
94 size_t event_size;
95 void *marker;
96
97 event_header = log->bios_event_log;
98
99 if (v == SEQ_START_TOKEN) {
100 event_size = sizeof(struct tcg_pcr_event) -
101 sizeof(event_header->event) + event_header->event_size;
102 marker = event_header;
103 } else {
104 event = v;
105 event_size = calc_tpm2_event_size(event, event_header);
106 if (event_size == 0)
107 return NULL;
108 marker = event;
109 }
110
111 marker = marker + event_size;
112 if (marker >= limit)
113 return NULL;
114 v = marker;
115 event = v;
116
117 event_size = calc_tpm2_event_size(event, event_header);
118 if (((v + event_size) >= limit) || (event_size == 0))
119 return NULL;
120
121 (*pos)++;
122 return v;
123 }
124
tpm2_bios_measurements_stop(struct seq_file * m,void * v)125 static void tpm2_bios_measurements_stop(struct seq_file *m, void *v)
126 {
127 }
128
tpm2_binary_bios_measurements_show(struct seq_file * m,void * v)129 static int tpm2_binary_bios_measurements_show(struct seq_file *m, void *v)
130 {
131 struct tpm_chip *chip = m->private;
132 struct tpm_bios_log *log = &chip->log;
133 struct tcg_pcr_event *event_header = log->bios_event_log;
134 struct tcg_pcr_event2_head *event = v;
135 void *temp_ptr;
136 size_t size;
137
138 if (v == SEQ_START_TOKEN) {
139 size = sizeof(struct tcg_pcr_event) -
140 sizeof(event_header->event) + event_header->event_size;
141
142 temp_ptr = event_header;
143
144 if (size > 0)
145 seq_write(m, temp_ptr, size);
146 } else {
147 size = calc_tpm2_event_size(event, event_header);
148 temp_ptr = event;
149 if (size > 0)
150 seq_write(m, temp_ptr, size);
151 }
152
153 return 0;
154 }
155
156 const struct seq_operations tpm2_binary_b_measurements_seqops = {
157 .start = tpm2_bios_measurements_start,
158 .next = tpm2_bios_measurements_next,
159 .stop = tpm2_bios_measurements_stop,
160 .show = tpm2_binary_bios_measurements_show,
161 };
162
