[PATCH] tpm: add bios measurement log

According to the TCG specifications measurements or hashes of the BIOS code
and data are extended into TPM PCRS and a log is kept in an ACPI table of
these extensions for later validation if desired.  This patch exports the
values in the ACPI table through a security-fs seq_file.

Signed-off-by: Seiji Munetoh <munetoh@jp.ibm.com>
Signed-off-by: Stefan Berger <stefanb@us.ibm.com>
Signed-off-by: Reiner Sailer <sailer@us.ibm.com>
Signed-off-by: Kylene Hall <kjhall@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 508 insertions, 0 deletions

diff --git a/drivers/char/tpm/tpm_bios.c b/drivers/char/tpm/tpm_bios.c
new file mode 100644
index 000000000000..5e1f4dfefa17
--- /dev/null
+++ b/drivers/char/tpm/tpm_bios.c
@@ -0,0 +1,508 @@
+/*
+ * Copyright (C) 2005 IBM Corporation
+ *
+ * Authors:
+ *	Seiji Munetoh <munetoh@jp.ibm.com>
+ *	Stefan Berger <stefanb@us.ibm.com>
+ *	Reiner Sailer <sailer@watson.ibm.com>
+ *	Kylene Hall <kjhall@us.ibm.com>
+ *
+ * Access to the eventlog extended by the TCG BIOS of PC platform
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ *
+ */
+
+#include <linux/seq_file.h>
+#include <linux/fs.h>
+#include <linux/security.h>
+#include <linux/module.h>
+#include <acpi/acpi.h>
+#include <acpi/actypes.h>
+#include <acpi/actbl.h>
+#include "tpm.h"
+
+#define TCG_EVENT_NAME_LEN_MAX	255
+#define MAX_TEXT_EVENT		1000	/* Max event string length */
+#define ACPI_TCPA_SIG		"TCPA"	/* 0x41504354 /'TCPA' */
+
+struct acpi_tcpa {
+	struct acpi_table_header hdr;
+	u16 reserved;
+	u32 log_max_len __attribute__ ((packed));
+	u32 log_start_addr __attribute__ ((packed));
+};
+
+struct tcpa_event {
+	u32 pcr_index;
+	u32 event_type;
+	u8 pcr_value[20];	/* SHA1 */
+	u32 event_size;
+	u8 event_data[0];
+};
+
+enum tcpa_event_types {
+	PREBOOT = 0,
+	POST_CODE,
+	UNUSED,
+	NO_ACTION,
+	SEPARATOR,
+	ACTION,
+	EVENT_TAG,
+	SCRTM_CONTENTS,
+	SCRTM_VERSION,
+	CPU_MICROCODE,
+	PLATFORM_CONFIG_FLAGS,
+	TABLE_OF_DEVICES,
+	COMPACT_HASH,
+	IPL,
+	IPL_PARTITION_DATA,
+	NONHOST_CODE,
+	NONHOST_CONFIG,
+	NONHOST_INFO,
+};
+
+static const char* tcpa_event_type_strings[] = {
+	"PREBOOT",
+	"POST CODE",
+	"",
+	"NO ACTION",
+	"SEPARATOR",
+	"ACTION",
+	"EVENT TAG",
+	"S-CRTM Contents",
+	"S-CRTM Version",
+	"CPU Microcode",
+	"Platform Config Flags",
+	"Table of Devices",
+	"Compact Hash",
+	"IPL",
+	"IPL Partition Data",
+	"Non-Host Code",
+	"Non-Host Config",
+	"Non-Host Info"
+};
+
+enum tcpa_pc_event_ids {
+	SMBIOS = 1,
+	BIS_CERT,
+	POST_BIOS_ROM,
+	ESCD,
+	CMOS,
+	NVRAM,
+	OPTION_ROM_EXEC,
+	OPTION_ROM_CONFIG,
+	OPTION_ROM_MICROCODE,
+	S_CRTM_VERSION,
+	S_CRTM_CONTENTS,
+	POST_CONTENTS,
+};
+
+static const char* tcpa_pc_event_id_strings[] = {
+	""
+	"SMBIOS",
+	"BIS Certificate",
+	"POST BIOS ",
+	"ESCD ",
+	"CMOS",
+	"NVRAM",
+	"Option ROM",
+	"Option ROM config",
+	"Option ROM microcode",
+	"S-CRTM Version",
+	"S-CRTM Contents",
+	"S-CRTM POST Contents",
+};
+
+/* (Binary) bios measurement buffer */
+static void *tcg_eventlog;
+static void *tcg_eventlog_addr_limit;	/* MAX */
+
+/* returns pointer to start of pos. entry of tcg log */
+static void *tpm_bios_measurements_start(struct seq_file *m, loff_t *pos)
+{
+	loff_t i;
+	void *addr = tcg_eventlog;
+	struct tcpa_event *event;
+
+	/* read over *pos measurements */
+	for (i = 0; i < *pos; i++) {
+		event = addr;
+
+		if ((addr + sizeof(struct tcpa_event)) <
+		    tcg_eventlog_addr_limit) {
+			if (event->event_type == 0 && event->event_size == 0)
+				return NULL;
+			addr +=
+			    sizeof(struct tcpa_event) + event->event_size;
+		}
+	}
+
+	/* now check if current entry is valid */
+	if ((addr + sizeof(struct tcpa_event)) >= tcg_eventlog_addr_limit)
+		return NULL;
+
+	event = addr;
+
+	if ((event->event_type == 0 && event->event_size == 0) ||
+	    ((addr + sizeof(struct tcpa_event) + event->event_size) >=
+	     tcg_eventlog_addr_limit))
+		return NULL;
+
+	return addr;
+}
+
+static void *tpm_bios_measurements_next(struct seq_file *m, void *v,
+					loff_t *pos)
+{
+	struct tcpa_event *event = v;
+
+	v += sizeof(struct tcpa_event) + event->event_size;
+
+	/* now check if current entry is valid */
+	if ((v + sizeof(struct tcpa_event)) >= tcg_eventlog_addr_limit)
+		return NULL;
+
+	event = v;
+
+	if (event->event_type == 0 && event->event_size == 0)
+		return NULL;
+
+	if ((event->event_type == 0 && event->event_size == 0) ||
+	    ((v + sizeof(struct tcpa_event) + event->event_size) >=
+	     tcg_eventlog_addr_limit))
+		return NULL;
+
+	(*pos)++;
+	return v;
+}
+
+static void tpm_bios_measurements_stop(struct seq_file *m, void *v)
+{
+}
+
+static int get_event_name(char *dest, struct tcpa_event *event,
+			unsigned char * event_entry)
+{
+	const char *name = "";
+	char data[40] = "";
+	int i, n_len = 0, d_len = 0;
+	u32 event_id, event_data_size;
+
+	switch(event->event_type) {
+	case PREBOOT:
+	case POST_CODE:
+	case UNUSED:
+	case NO_ACTION:
+	case SCRTM_CONTENTS:
+	case SCRTM_VERSION:
+	case CPU_MICROCODE:
+	case PLATFORM_CONFIG_FLAGS:
+	case TABLE_OF_DEVICES:
+	case COMPACT_HASH:
+	case IPL:
+	case IPL_PARTITION_DATA:
+	case NONHOST_CODE:
+	case NONHOST_CONFIG:
+	case NONHOST_INFO:
+		name = tcpa_event_type_strings[event->event_type];
+		n_len = strlen(name);
+		break;
+	case SEPARATOR:
+	case ACTION:
+		if (MAX_TEXT_EVENT > event->event_size) {
+			name = event_entry;
+			n_len = event->event_size;
+		}
+		break;
+	case EVENT_TAG:
+		event_id = be32_to_cpu(event_entry);
+		event_data_size = be32_to_cpu(&event_entry[4]);
+
+		/* ToDo Row data -> Base64 */
+
+		switch (event_id) {
+		case SMBIOS:
+		case BIS_CERT:
+		case CMOS:
+		case NVRAM:
+		case OPTION_ROM_EXEC:
+		case OPTION_ROM_CONFIG:
+		case OPTION_ROM_MICROCODE:
+		case S_CRTM_VERSION:
+		case S_CRTM_CONTENTS:
+		case POST_CONTENTS:
+			name = tcpa_pc_event_id_strings[event_id];
+			n_len = strlen(name);
+			break;
+		case POST_BIOS_ROM:
+		case ESCD:
+			name = tcpa_pc_event_id_strings[event_id];
+			n_len = strlen(name);
+			for (i = 0; i < 20; i++)
+				d_len += sprintf(data, "%02x",
+						event_entry[8 + i]);
+			break;
+		default:
+			break;
+		}
+	default:
+		break;
+	}
+
+	return snprintf(dest, MAX_TEXT_EVENT, "[%.*s%.*s]",
+			n_len, name, d_len, data);
+
+}
+
+static int tpm_binary_bios_measurements_show(struct seq_file *m, void *v)
+{
+
+	char *eventname;
+	char data[4];
+	u32 help;
+	int i, len;
+	struct tcpa_event *event = (struct tcpa_event *) v;
+	unsigned char *event_entry =
+	    (unsigned char *) (v + sizeof(struct tcpa_event));
+
+	eventname = kmalloc(MAX_TEXT_EVENT, GFP_KERNEL);
+	if (!eventname) {
+		printk(KERN_ERR "%s: ERROR - No Memory for event name\n ",
+		       __func__);
+		return -ENOMEM;
+	}
+
+	/* 1st: PCR used is in little-endian format (4 bytes) */
+	help = le32_to_cpu(event->pcr_index);
+	memcpy(data, &help, 4);
+	for (i = 0; i < 4; i++)
+		seq_putc(m, data[i]);
+
+	/* 2nd: SHA1 (20 bytes) */
+	for (i = 0; i < 20; i++)
+		seq_putc(m, event->pcr_value[i]);
+
+	/* 3rd: event type identifier (4 bytes) */
+	help = le32_to_cpu(event->event_type);
+	memcpy(data, &help, 4);
+	for (i = 0; i < 4; i++)
+		seq_putc(m, data[i]);
+
+	len = 0;
+
+	len += get_event_name(eventname, event, event_entry);
+
+	/* 4th:  filename <= 255 + \'0' delimiter */
+	if (len > TCG_EVENT_NAME_LEN_MAX)
+		len = TCG_EVENT_NAME_LEN_MAX;
+
+	for (i = 0; i < len; i++)
+		seq_putc(m, eventname[i]);
+
+	/* 5th: delimiter */
+	seq_putc(m, '\0');
+
+	return 0;
+}
+
+static int tpm_bios_measurements_release(struct inode *inode,
+					 struct file *file)
+{
+	if (tcg_eventlog) {
+		kfree(tcg_eventlog);
+		tcg_eventlog = NULL;
+	}
+	return seq_release(inode, file);
+}
+
+static int tpm_ascii_bios_measurements_show(struct seq_file *m, void *v)
+{
+	int len = 0;
+	int i;
+	char *eventname;
+	struct tcpa_event *event = v;
+	unsigned char *event_entry =
+	    (unsigned char *) (v + sizeof(struct tcpa_event));
+
+	eventname = kmalloc(MAX_TEXT_EVENT, GFP_KERNEL);
+	if (!eventname) {
+		printk(KERN_ERR "%s: ERROR - No Memory for event name\n ",
+		       __func__);
+		return -EFAULT;
+	}
+
+	seq_printf(m, "%2d ", event->pcr_index);
+
+	/* 2nd: SHA1 */
+	for (i = 0; i < 20; i++)
+		seq_printf(m, "%02x", event->pcr_value[i]);
+
+	/* 3rd: event type identifier */
+	seq_printf(m, " %02x", event->event_type);
+
+	len += get_event_name(eventname, event, event_entry);
+
+	/* 4th: eventname <= max + \'0' delimiter */
+	seq_printf(m, " %s\n", eventname);
+
+	return 0;
+}
+
+static struct seq_operations tpm_ascii_b_measurments_seqops = {
+	.start = tpm_bios_measurements_start,
+	.next = tpm_bios_measurements_next,
+	.stop = tpm_bios_measurements_stop,
+	.show = tpm_ascii_bios_measurements_show,
+};
+
+static struct seq_operations tpm_binary_b_measurments_seqops = {
+	.start = tpm_bios_measurements_start,
+	.next = tpm_bios_measurements_next,
+	.stop = tpm_bios_measurements_stop,
+	.show = tpm_binary_bios_measurements_show,
+};
+
+/* read binary bios log */
+static int read_log(void)
+{
+	struct acpi_tcpa *buff;
+	acpi_status status;
+	void *virt;
+
+	if (tcg_eventlog != NULL) {
+		printk(KERN_ERR
+		       "%s: ERROR - Eventlog already initialized\n",
+		       __func__);
+		return -EFAULT;
+	}
+
+	/* Find TCPA entry in RSDT (ACPI_LOGICAL_ADDRESSING) */
+	status = acpi_get_firmware_table(ACPI_TCPA_SIG, 1,
+					 ACPI_LOGICAL_ADDRESSING,
+					 (struct acpi_table_header **)
+					 &buff);
+
+	if (ACPI_FAILURE(status)) {
+		printk(KERN_ERR "%s: ERROR - Could not get TCPA table\n",
+		       __func__);
+		return -EIO;
+	}
+
+	if (buff->log_max_len == 0) {
+		printk(KERN_ERR "%s: ERROR - TCPA log area empty\n",
+		       __func__);
+		return -EIO;
+	}
+
+	/* malloc EventLog space */
+	tcg_eventlog = kmalloc(buff->log_max_len, GFP_KERNEL);
+	if (!tcg_eventlog) {
+		printk
+		    ("%s: ERROR - Not enough  Memory for BIOS measurements\n",
+		     __func__);
+		return -ENOMEM;
+	}
+
+	tcg_eventlog_addr_limit = tcg_eventlog + buff->log_max_len;
+
+	acpi_os_map_memory(buff->log_start_addr, buff->log_max_len, &virt);
+
+	memcpy(tcg_eventlog, virt, buff->log_max_len);
+
+	acpi_os_unmap_memory(virt, buff->log_max_len);
+	return 0;
+}
+
+static int tpm_ascii_bios_measurements_open(struct inode *inode,
+					    struct file *file)
+{
+	int err;
+
+	if ((err = read_log()))
+		return err;
+
+	/* now register seq file */
+	return seq_open(file, &tpm_ascii_b_measurments_seqops);
+}
+
+struct file_operations tpm_ascii_bios_measurements_ops = {
+	.open = tpm_ascii_bios_measurements_open,
+	.read = seq_read,
+	.llseek = seq_lseek,
+	.release = tpm_bios_measurements_release,
+};
+
+static int tpm_binary_bios_measurements_open(struct inode *inode,
+					     struct file *file)
+{
+	int err;
+
+	if ((err = read_log()))
+		return err;
+
+	/* now register seq file */
+	return seq_open(file, &tpm_binary_b_measurments_seqops);
+}
+
+struct file_operations tpm_binary_bios_measurements_ops = {
+	.open = tpm_binary_bios_measurements_open,
+	.read = seq_read,
+	.llseek = seq_lseek,
+	.release = tpm_bios_measurements_release,
+};
+
+struct dentry **tpm_bios_log_setup(char *name)
+{
+	struct dentry **ret = NULL, *tpm_dir, *bin_file, *ascii_file;
+
+	tpm_dir = securityfs_create_dir(name, NULL);
+	if (!tpm_dir)
+		goto out;
+
+	bin_file =
+	    securityfs_create_file("binary_bios_measurements",
+				   S_IRUSR | S_IRGRP, tpm_dir, NULL,
+				   &tpm_binary_bios_measurements_ops);
+	if (!bin_file)
+		goto out_tpm;
+
+	ascii_file =
+	    securityfs_create_file("ascii_bios_measurements",
+				   S_IRUSR | S_IRGRP, tpm_dir, NULL,
+				   &tpm_ascii_bios_measurements_ops);
+	if (!ascii_file)
+		goto out_bin;
+
+	ret = kmalloc(3 * sizeof(struct dentry *), GFP_KERNEL);
+	if (!ret)
+		goto out_ascii;
+
+	ret[0] = ascii_file;
+	ret[1] = bin_file;
+	ret[2] = tpm_dir;
+
+	return ret;
+
+out_ascii:
+	securityfs_remove(ascii_file);
+out_bin:
+	securityfs_remove(bin_file);
+out_tpm:
+	securityfs_remove(tpm_dir);
+out:
+	return NULL;
+}
+EXPORT_SYMBOL_GPL(tpm_bios_log_setup);
+
+void tpm_bios_log_teardown(struct dentry **lst)
+{
+	int i;
+
+	for (i = 0; i < 3; i++)
+		securityfs_remove(lst[i]);
+}
+EXPORT_SYMBOL_GPL(tpm_bios_log_teardown);