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 struct linux_efi_tpm_eventlog *log_tbl;
21 struct tpm_bios_log *log;
22 u32 log_size;
23 u8 tpm_log_version;
24 void *tmp;
25 int ret;
26
27 if (!(chip->flags & TPM_CHIP_FLAG_TPM2))
28 return -ENODEV;
29
30 if (efi.tpm_log == EFI_INVALID_TABLE_ADDR)
31 return -ENODEV;
32
33 log = &chip->log;
34
35 log_tbl = memremap(efi.tpm_log, sizeof(*log_tbl), MEMREMAP_WB);
36 if (!log_tbl) {
37 pr_err("Could not map UEFI TPM log table !\n");
38 return -ENOMEM;
39 }
40
41 log_size = log_tbl->size;
42 memunmap(log_tbl);
43
44 if (!log_size) {
45 pr_warn("UEFI TPM log area empty\n");
46 return -EIO;
47 }
48
49 log_tbl = memremap(efi.tpm_log, sizeof(*log_tbl) + log_size,
50 MEMREMAP_WB);
51 if (!log_tbl) {
52 pr_err("Could not map UEFI TPM log table payload!\n");
53 return -ENOMEM;
54 }
55
56 /* malloc EventLog space */
57 log->bios_event_log = kmemdup(log_tbl->log, log_size, GFP_KERNEL);
58 if (!log->bios_event_log) {
59 ret = -ENOMEM;
60 goto out;
61 }
62
63 log->bios_event_log_end = log->bios_event_log + log_size;
64 tpm_log_version = log_tbl->version;
65
66 ret = tpm_log_version;
67
68 if (efi.tpm_final_log == EFI_INVALID_TABLE_ADDR ||
69 efi_tpm_final_log_size == 0 ||
70 tpm_log_version != EFI_TCG2_EVENT_LOG_FORMAT_TCG_2)
71 goto out;
72
73 final_tbl = memremap(efi.tpm_final_log,
74 sizeof(*final_tbl) + efi_tpm_final_log_size,
75 MEMREMAP_WB);
76 if (!final_tbl) {
77 pr_err("Could not map UEFI TPM final log\n");
78 kfree(log->bios_event_log);
79 ret = -ENOMEM;
80 goto out;
81 }
82
83 efi_tpm_final_log_size -= log_tbl->final_events_preboot_size;
84
85 tmp = krealloc(log->bios_event_log,
86 log_size + efi_tpm_final_log_size,
87 GFP_KERNEL);
88 if (!tmp) {
89 kfree(log->bios_event_log);
90 ret = -ENOMEM;
91 goto out;
92 }
93
94 log->bios_event_log = tmp;
95
96 /*
97 * Copy any of the final events log that didn't also end up in the
98 * main log. Events can be logged in both if events are generated
99 * between GetEventLog() and ExitBootServices().
100 */
101 memcpy((void *)log->bios_event_log + log_size,
102 final_tbl->events + log_tbl->final_events_preboot_size,
103 efi_tpm_final_log_size);
104 log->bios_event_log_end = log->bios_event_log +
105 log_size + efi_tpm_final_log_size;
106
107 out:
108 memunmap(final_tbl);
109 memunmap(log_tbl);
110 return ret;
111 }
112