1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Copyright (C) 2017 Google
4 *
5 * Authors:
6 * Thiebaud Weksteen <tweek@google.com>
7 */
8
9 #include <linux/device.h>
10 #include <linux/efi.h>
11 #include <linux/tpm_eventlog.h>
12
13 #include "../tpm.h"
14 #include "common.h"
15
16 /* read binary bios log from EFI configuration table */
tpm_read_log_efi(struct tpm_chip * chip)17 int tpm_read_log_efi(struct tpm_chip *chip)
18 {
19
20 struct efi_tcg2_final_events_table *final_tbl = NULL;
21 int final_events_log_size = efi_tpm_final_log_size;
22 struct linux_efi_tpm_eventlog *log_tbl;
23 struct tpm_bios_log *log;
24 u32 log_size;
25 u8 tpm_log_version;
26 void *tmp;
27 int ret;
28
29 if (!(chip->flags & TPM_CHIP_FLAG_TPM2))
30 return -ENODEV;
31
32 if (efi.tpm_log == EFI_INVALID_TABLE_ADDR)
33 return -ENODEV;
34
35 log = &chip->log;
36
37 log_tbl = memremap(efi.tpm_log, sizeof(*log_tbl), MEMREMAP_WB);
38 if (!log_tbl) {
39 pr_err("Could not map UEFI TPM log table !\n");
40 return -ENOMEM;
41 }
42
43 log_size = log_tbl->size;
44 memunmap(log_tbl);
45
46 if (!log_size) {
47 pr_warn("UEFI TPM log area empty\n");
48 return -EIO;
49 }
50
51 log_tbl = memremap(efi.tpm_log, sizeof(*log_tbl) + log_size,
52 MEMREMAP_WB);
53 if (!log_tbl) {
54 pr_err("Could not map UEFI TPM log table payload!\n");
55 return -ENOMEM;
56 }
57
58 /* malloc EventLog space */
59 log->bios_event_log = devm_kmemdup(&chip->dev, log_tbl->log, log_size, GFP_KERNEL);
60 if (!log->bios_event_log) {
61 ret = -ENOMEM;
62 goto out;
63 }
64
65 log->bios_event_log_end = log->bios_event_log + log_size;
66 tpm_log_version = log_tbl->version;
67
68 ret = tpm_log_version;
69
70 if (efi.tpm_final_log == EFI_INVALID_TABLE_ADDR ||
71 final_events_log_size == 0 ||
72 tpm_log_version != EFI_TCG2_EVENT_LOG_FORMAT_TCG_2)
73 goto out;
74
75 final_tbl = memremap(efi.tpm_final_log,
76 sizeof(*final_tbl) + final_events_log_size,
77 MEMREMAP_WB);
78 if (!final_tbl) {
79 pr_err("Could not map UEFI TPM final log\n");
80 devm_kfree(&chip->dev, log->bios_event_log);
81 ret = -ENOMEM;
82 goto out;
83 }
84
85 /*
86 * The 'final events log' size excludes the 'final events preboot log'
87 * at its beginning.
88 */
89 final_events_log_size -= log_tbl->final_events_preboot_size;
90
91 /*
92 * Allocate memory for the 'combined log' where we will append the
93 * 'final events log' to.
94 */
95 tmp = devm_krealloc(&chip->dev, log->bios_event_log,
96 log_size + final_events_log_size,
97 GFP_KERNEL);
98 if (!tmp) {
99 devm_kfree(&chip->dev, log->bios_event_log);
100 ret = -ENOMEM;
101 goto out;
102 }
103
104 log->bios_event_log = tmp;
105
106 /*
107 * Append any of the 'final events log' that didn't also end up in the
108 * 'main log'. Events can be logged in both if events are generated
109 * between GetEventLog() and ExitBootServices().
110 */
111 memcpy((void *)log->bios_event_log + log_size,
112 final_tbl->events + log_tbl->final_events_preboot_size,
113 final_events_log_size);
114 /*
115 * The size of the 'combined log' is the size of the 'main log' plus
116 * the size of the 'final events log'.
117 */
118 log->bios_event_log_end = log->bios_event_log +
119 log_size + final_events_log_size;
120
121 out:
122 memunmap(final_tbl);
123 memunmap(log_tbl);
124 return ret;
125 }
126