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