[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>

4 files changed, 529 insertions, 0 deletions

diff --git a/drivers/char/tpm/Makefile b/drivers/char/tpm/Makefile
index 2392e404e8d1..ba4582d160fd 100644
--- a/drivers/char/tpm/Makefile
+++ b/drivers/char/tpm/Makefile
@@ -2,6 +2,9 @@
 # Makefile for the kernel tpm device drivers.
 #
 obj-$(CONFIG_TCG_TPM) += tpm.o
+ifdef CONFIG_ACPI
+        obj-$(CONFIG_TCG_TPM) += tpm_bios.o
+endif
 obj-$(CONFIG_TCG_NSC) += tpm_nsc.o
 obj-$(CONFIG_TCG_ATMEL) += tpm_atmel.o
 obj-$(CONFIG_TCG_INFINEON) += tpm_infineon.o
diff --git a/drivers/char/tpm/tpm.c b/drivers/char/tpm/tpm.c
index a9be0e8eaea5..5a3870477ef1 100644
--- a/drivers/char/tpm/tpm.c
+++ b/drivers/char/tpm/tpm.c
@@ -466,6 +466,7 @@ void tpm_remove_hardware(struct device *dev)
         kfree(chip->vendor->miscdev.name);
 
         sysfs_remove_group(&dev->kobj, chip->vendor->attr_group);
+        tpm_bios_log_teardown(chip->bios_dir);
 
         dev_mask[chip->dev_num / TPM_NUM_MASK_ENTRIES ] &=
                 ~(1 << (chip->dev_num % TPM_NUM_MASK_ENTRIES));
@@ -593,6 +594,8 @@ dev_num_search_complete:
 
         sysfs_create_group(&dev->kobj, chip->vendor->attr_group);
 
+        chip->bios_dir = tpm_bios_log_setup(devname);
+
         return 0;
 }
 EXPORT_SYMBOL_GPL(tpm_register_hardware);
diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
index 159882ca69dd..fd3a4beaa53d 100644
--- a/drivers/char/tpm/tpm.h
+++ b/drivers/char/tpm/tpm.h
@@ -82,6 +82,8 @@ struct tpm_chip {
 
         struct tpm_vendor_specific *vendor;
 
+        struct dentry **bios_dir;
+
         struct list_head list;
 };
 
@@ -107,3 +109,16 @@ extern ssize_t tpm_read(struct file *, char __user *, size_t, loff_t *);
 extern void tpm_remove_hardware(struct device *);
 extern int tpm_pm_suspend(struct device *, pm_message_t);
 extern int tpm_pm_resume(struct device *);
+
+#ifdef CONFIG_ACPI
+extern struct dentry ** tpm_bios_log_setup(char *);
+extern void tpm_bios_log_teardown(struct dentry **);
+#else
+static inline struct dentry* tpm_bios_log_setup(char *name)
+{
+        return NULL;
+}
+static inline void tpm_bios_log_teardown(struct dentry **dir)
+{
+}
+#endif
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);