LXR linux/drivers/char/tpm/eventlog/acpi.c

   1// SPDX-License-Identifier: GPL-2.0-or-later
   2/*
   3 * Copyright (C) 2005 IBM Corporation
   4 *
   5 * Authors:
   6 *      Seiji Munetoh <munetoh@jp.ibm.com>
   7 *      Stefan Berger <stefanb@us.ibm.com>
   8 *      Reiner Sailer <sailer@watson.ibm.com>
   9 *      Kylene Hall <kjhall@us.ibm.com>
  10 *      Nayna Jain <nayna@linux.vnet.ibm.com>
  11 *
  12 * Maintained by: <tpmdd-devel@lists.sourceforge.net>
  13 *
  14 * Access to the event log extended by the TCG BIOS of PC platform
  15 */
  16
  17#include <linux/seq_file.h>
  18#include <linux/fs.h>
  19#include <linux/security.h>
  20#include <linux/module.h>
  21#include <linux/slab.h>
  22#include <linux/acpi.h>
  23#include <linux/tpm_eventlog.h>
  24
  25#include "../tpm.h"
  26#include "common.h"
  27
  28struct acpi_tcpa {
  29        struct acpi_table_header hdr;
  30        u16 platform_class;
  31        union {
  32                struct client_hdr {
  33                        u32 log_max_len __packed;
  34                        u64 log_start_addr __packed;
  35                } client;
  36                struct server_hdr {
  37                        u16 reserved;
  38                        u64 log_max_len __packed;
  39                        u64 log_start_addr __packed;
  40                } server;
  41        };
  42};
  43
  44/* Check that the given log is indeed a TPM2 log. */
  45static bool tpm_is_tpm2_log(void *bios_event_log, u64 len)
  46{
  47        struct tcg_efi_specid_event_head *efispecid;
  48        struct tcg_pcr_event *event_header;
  49        int n;
  50
  51        if (len < sizeof(*event_header))
  52                return false;
  53        len -= sizeof(*event_header);
  54        event_header = bios_event_log;
  55
  56        if (len < sizeof(*efispecid))
  57                return false;
  58        efispecid = (struct tcg_efi_specid_event_head *)event_header->event;
  59
  60        n = memcmp(efispecid->signature, TCG_SPECID_SIG,
  61                   sizeof(TCG_SPECID_SIG));
  62        return n == 0;
  63}
  64
  65/* read binary bios log */
  66int tpm_read_log_acpi(struct tpm_chip *chip)
  67{
  68        struct acpi_tcpa *buff;
  69        acpi_status status;
  70        void __iomem *virt;
  71        u64 len, start;
  72        struct tpm_bios_log *log;
  73        struct acpi_table_tpm2 *tbl;
  74        struct acpi_tpm2_phy *tpm2_phy;
  75        int format;
  76        int ret;
  77
  78        log = &chip->log;
  79
  80        /* Unfortuntely ACPI does not associate the event log with a specific
  81         * TPM, like PPI. Thus all ACPI TPMs will read the same log.
  82         */
  83        if (!chip->acpi_dev_handle)
  84                return -ENODEV;
  85
  86        if (chip->flags & TPM_CHIP_FLAG_TPM2) {
  87                status = acpi_get_table("TPM2", 1,
  88                                        (struct acpi_table_header **)&tbl);
  89                if (ACPI_FAILURE(status))
  90                        return -ENODEV;
  91
  92                if (tbl->header.length <
  93                                sizeof(*tbl) + sizeof(struct acpi_tpm2_phy))
  94                        return -ENODEV;
  95
  96                tpm2_phy = (void *)tbl + sizeof(*tbl);
  97                len = tpm2_phy->log_area_minimum_length;
  98
  99                start = tpm2_phy->log_area_start_address;
 100                if (!start || !len)
 101                        return -ENODEV;
 102
 103                format = EFI_TCG2_EVENT_LOG_FORMAT_TCG_2;
 104        } else {
 105                /* Find TCPA entry in RSDT (ACPI_LOGICAL_ADDRESSING) */
 106                status = acpi_get_table(ACPI_SIG_TCPA, 1,
 107                                        (struct acpi_table_header **)&buff);
 108                if (ACPI_FAILURE(status))
 109                        return -ENODEV;
 110
 111                switch (buff->platform_class) {
 112                case BIOS_SERVER:
 113                        len = buff->server.log_max_len;
 114                        start = buff->server.log_start_addr;
 115                        break;
 116                case BIOS_CLIENT:
 117                default:
 118                        len = buff->client.log_max_len;
 119                        start = buff->client.log_start_addr;
 120                        break;
 121                }
 122
 123                format = EFI_TCG2_EVENT_LOG_FORMAT_TCG_1_2;
 124        }
 125        if (!len) {
 126                dev_warn(&chip->dev, "%s: TCPA log area empty\n", __func__);
 127                return -EIO;
 128        }
 129
 130        /* malloc EventLog space */
 131        log->bios_event_log = kmalloc(len, GFP_KERNEL);
 132        if (!log->bios_event_log)
 133                return -ENOMEM;
 134
 135        log->bios_event_log_end = log->bios_event_log + len;
 136
 137        ret = -EIO;
 138        virt = acpi_os_map_iomem(start, len);
 139        if (!virt)
 140                goto err;
 141
 142        memcpy_fromio(log->bios_event_log, virt, len);
 143
 144        acpi_os_unmap_iomem(virt, len);
 145
 146        if (chip->flags & TPM_CHIP_FLAG_TPM2 &&
 147            !tpm_is_tpm2_log(log->bios_event_log, len)) {
 148                /* try EFI log next */
 149                ret = -ENODEV;
 150                goto err;
 151        }
 152
 153        return format;
 154
 155err:
 156        kfree(log->bios_event_log);
 157        log->bios_event_log = NULL;
 158        return ret;
 159
 160}
 161