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 28 struct 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. */ 45 static 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 */ 66 int 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; 154 155 err: 156 kfree(log->bios_event_log); 157 log->bios_event_log = NULL; 158 return ret; 159 160 } 161