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 */
16int 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
120out:
121	memunmap(final_tbl);
122	memunmap(log_tbl);
123	return ret;
124}
125