162 lines
4.0 KiB
C
162 lines
4.0 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* Copyright (C) 2016 IBM Corporation
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*
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* Authors:
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* Nayna Jain <nayna@linux.vnet.ibm.com>
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*
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* Access to TPM 2.0 event log as written by Firmware.
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* It assumes that writer of event log has followed TCG Specification
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* for Family "2.0" and written the event data in little endian.
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* With that, it doesn't need any endian conversion for structure
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* content.
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*/
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#include <linux/seq_file.h>
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#include <linux/fs.h>
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#include <linux/security.h>
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#include <linux/module.h>
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#include <linux/slab.h>
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#include <linux/tpm_eventlog.h>
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#include "../tpm.h"
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#include "common.h"
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/*
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* calc_tpm2_event_size() - calculate the event size, where event
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* is an entry in the TPM 2.0 event log. The event is of type Crypto
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* Agile Log Entry Format as defined in TCG EFI Protocol Specification
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* Family "2.0".
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* @event: event whose size is to be calculated.
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* @event_header: the first event in the event log.
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*
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* Returns size of the event. If it is an invalid event, returns 0.
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*/
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static size_t calc_tpm2_event_size(struct tcg_pcr_event2_head *event,
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struct tcg_pcr_event *event_header)
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{
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return __calc_tpm2_event_size(event, event_header, false);
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}
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static void *tpm2_bios_measurements_start(struct seq_file *m, loff_t *pos)
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{
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struct tpm_chip *chip = m->private;
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struct tpm_bios_log *log = &chip->log;
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void *addr = log->bios_event_log;
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void *limit = log->bios_event_log_end;
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struct tcg_pcr_event *event_header;
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struct tcg_pcr_event2_head *event;
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size_t size;
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int i;
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event_header = addr;
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size = sizeof(struct tcg_pcr_event) - sizeof(event_header->event)
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+ event_header->event_size;
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if (*pos == 0) {
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if (addr + size < limit) {
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if ((event_header->event_type == 0) &&
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(event_header->event_size == 0))
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return NULL;
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return SEQ_START_TOKEN;
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}
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}
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if (*pos > 0) {
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addr += size;
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event = addr;
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size = calc_tpm2_event_size(event, event_header);
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if ((addr + size >= limit) || (size == 0))
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return NULL;
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}
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for (i = 0; i < (*pos - 1); i++) {
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event = addr;
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size = calc_tpm2_event_size(event, event_header);
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if ((addr + size >= limit) || (size == 0))
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return NULL;
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addr += size;
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}
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return addr;
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}
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static void *tpm2_bios_measurements_next(struct seq_file *m, void *v,
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loff_t *pos)
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{
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struct tcg_pcr_event *event_header;
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struct tcg_pcr_event2_head *event;
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struct tpm_chip *chip = m->private;
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struct tpm_bios_log *log = &chip->log;
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void *limit = log->bios_event_log_end;
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size_t event_size;
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void *marker;
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event_header = log->bios_event_log;
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if (v == SEQ_START_TOKEN) {
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event_size = sizeof(struct tcg_pcr_event) -
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sizeof(event_header->event) + event_header->event_size;
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marker = event_header;
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} else {
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event = v;
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event_size = calc_tpm2_event_size(event, event_header);
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if (event_size == 0)
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return NULL;
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marker = event;
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}
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marker = marker + event_size;
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if (marker >= limit)
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return NULL;
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v = marker;
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event = v;
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event_size = calc_tpm2_event_size(event, event_header);
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if (((v + event_size) >= limit) || (event_size == 0))
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return NULL;
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(*pos)++;
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return v;
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}
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static void tpm2_bios_measurements_stop(struct seq_file *m, void *v)
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{
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}
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static int tpm2_binary_bios_measurements_show(struct seq_file *m, void *v)
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{
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struct tpm_chip *chip = m->private;
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struct tpm_bios_log *log = &chip->log;
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struct tcg_pcr_event *event_header = log->bios_event_log;
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struct tcg_pcr_event2_head *event = v;
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void *temp_ptr;
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size_t size;
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if (v == SEQ_START_TOKEN) {
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size = sizeof(struct tcg_pcr_event) -
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sizeof(event_header->event) + event_header->event_size;
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temp_ptr = event_header;
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if (size > 0)
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seq_write(m, temp_ptr, size);
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} else {
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size = calc_tpm2_event_size(event, event_header);
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temp_ptr = event;
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if (size > 0)
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seq_write(m, temp_ptr, size);
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}
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return 0;
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}
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const struct seq_operations tpm2_binary_b_measurements_seqops = {
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.start = tpm2_bios_measurements_start,
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.next = tpm2_bios_measurements_next,
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.stop = tpm2_bios_measurements_stop,
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.show = tpm2_binary_bios_measurements_show,
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};
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