/*
 * Copyright (C) 2005, 2012 IBM Corporation
 *
 * Authors:
 *      Kent Yoder <key@linux.vnet.ibm.com>
 *      Seiji Munetoh <munetoh@jp.ibm.com>
 *      Stefan Berger <stefanb@us.ibm.com>
 *      Reiner Sailer <sailer@watson.ibm.com>
 *      Kylene Hall <kjhall@us.ibm.com>
 *      Nayna Jain <nayna@linux.vnet.ibm.com>
 *
 * Maintained by: <tpmdd-devel@lists.sourceforge.net>
 *
 * Access to the event log created by a system's firmware / BIOS
 *
 * 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 <linux/slab.h>

#include "tpm.h"
#include "tpm_eventlog.h"


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"
};

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 ",
        "POST Contents ",
        "Table of Devices",
};

/* 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;
        struct tpm_chip *chip = m->private;
        struct tpm_bios_log *log = &chip->log;
        void *addr = log->bios_event_log;
        void *limit = log->bios_event_log_end;
        struct tcpa_event *event;
        u32 converted_event_size;
        u32 converted_event_type;


        /* read over *pos measurements */
        for (i = 0; i < *pos; i++) {
                event = addr;

                converted_event_size =
                    do_endian_conversion(event->event_size);
                converted_event_type =
                    do_endian_conversion(event->event_type);

                if ((addr + sizeof(struct tcpa_event)) < limit) {
                        if ((converted_event_type == 0) &&
                            (converted_event_size == 0))
                                return NULL;
                        addr += (sizeof(struct tcpa_event) +
                                 converted_event_size);
                }
        }

        /* now check if current entry is valid */
        if ((addr + sizeof(struct tcpa_event)) >= limit)
                return NULL;

        event = addr;

        converted_event_size = do_endian_conversion(event->event_size);
        converted_event_type = do_endian_conversion(event->event_type);

        if (((converted_event_type == 0) && (converted_event_size == 0))
            || ((addr + sizeof(struct tcpa_event) + converted_event_size)
                >= 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;
        struct tpm_chip *chip = m->private;
        struct tpm_bios_log *log = &chip->log;
        void *limit = log->bios_event_log_end;
        u32 converted_event_size;
        u32 converted_event_type;

        converted_event_size = do_endian_conversion(event->event_size);

        v += sizeof(struct tcpa_event) + converted_event_size;

        /* now check if current entry is valid */
        if ((v + sizeof(struct tcpa_event)) >= limit)
                return NULL;

        event = v;

        converted_event_size = do_endian_conversion(event->event_size);
        converted_event_type = do_endian_conversion(event->event_type);

        if (((converted_event_type == 0) && (converted_event_size == 0)) ||
            ((v + sizeof(struct tcpa_event) + converted_event_size) >= 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 = "";
        /* 41 so there is room for 40 data and 1 nul */
        char data[41] = "";
        int i, n_len = 0, d_len = 0;
        struct tcpa_pc_event *pc_event;

        switch (do_endian_conversion(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[do_endian_conversion
                                                (event->event_type)];
                n_len = strlen(name);
                break;
        case SEPARATOR:
        case ACTION:
                if (MAX_TEXT_EVENT >
                    do_endian_conversion(event->event_size)) {
                        name = event_entry;
                        n_len = do_endian_conversion(event->event_size);
                }
                break;
        case EVENT_TAG:
                pc_event = (struct tcpa_pc_event *)event_entry;

                /* ToDo Row data -> Base64 */

                switch (do_endian_conversion(pc_event->event_id)) {
                case SMBIOS:
                case BIS_CERT:
                case CMOS:
                case NVRAM:
                case OPTION_ROM_EXEC:
                case OPTION_ROM_CONFIG:
                case S_CRTM_VERSION:
                        name = tcpa_pc_event_id_strings[do_endian_conversion
                                                        (pc_event->event_id)];
                        n_len = strlen(name);
                        break;
                /* hash data */
                case POST_BIOS_ROM:
                case ESCD:
                case OPTION_ROM_MICROCODE:
                case S_CRTM_CONTENTS:
                case POST_CONTENTS:
                        name = tcpa_pc_event_id_strings[do_endian_conversion
                                                        (pc_event->event_id)];
                        n_len = strlen(name);
                        for (i = 0; i < 20; i++)
                                d_len += sprintf(&data[2*i], "%02x",
                                                pc_event->event_data[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)
{
        struct tcpa_event *event = v;
        struct tcpa_event temp_event;
        char *temp_ptr;
        int i;

        memcpy(&temp_event, event, sizeof(struct tcpa_event));

        /* convert raw integers for endianness */
        temp_event.pcr_index = do_endian_conversion(event->pcr_index);
        temp_event.event_type = do_endian_conversion(event->event_type);
        temp_event.event_size = do_endian_conversion(event->event_size);

        temp_ptr = (char *) &temp_event;

        for (i = 0; i < (sizeof(struct tcpa_event) - 1) ; i++)
                seq_putc(m, temp_ptr[i]);

        temp_ptr = (char *) v;

        for (i = (sizeof(struct tcpa_event) - 1);
             i < (sizeof(struct tcpa_event) + temp_event.event_size); i++)
                seq_putc(m, temp_ptr[i]);

        return 0;

}

static int tpm_bios_measurements_release(struct inode *inode,
                                         struct file *file)
{
        struct seq_file *seq = (struct seq_file *)file->private_data;
        struct tpm_chip *chip = (struct tpm_chip *)seq->private;

        put_device(&chip->dev);

        return seq_release(inode, file);
}

static int tpm_ascii_bios_measurements_show(struct seq_file *m, void *v)
{
        int len = 0;
        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;
        }

        /* 1st: PCR */
        seq_printf(m, "%2d ", do_endian_conversion(event->pcr_index));

        /* 2nd: SHA1 */
        seq_printf(m, "%20phN", event->pcr_value);

        /* 3rd: event type identifier */
        seq_printf(m, " %02x", do_endian_conversion(event->event_type));

        len += get_event_name(eventname, event, event_entry);

        /* 4th: eventname <= max + \'0' delimiter */
        seq_printf(m, " %s\n", eventname);

        kfree(eventname);
        return 0;
}

static const struct seq_operations tpm_ascii_b_measurements_seqops = {
        .start = tpm_bios_measurements_start,
        .next = tpm_bios_measurements_next,
        .stop = tpm_bios_measurements_stop,
        .show = tpm_ascii_bios_measurements_show,
};

static const struct seq_operations tpm_binary_b_measurements_seqops = {
        .start = tpm_bios_measurements_start,
        .next = tpm_bios_measurements_next,
        .stop = tpm_bios_measurements_stop,
        .show = tpm_binary_bios_measurements_show,
};

static int tpm_bios_measurements_open(struct inode *inode,
                                            struct file *file)
{
        int err;
        struct seq_file *seq;
        struct tpm_chip_seqops *chip_seqops;
        const struct seq_operations *seqops;
        struct tpm_chip *chip;

        inode_lock(inode);
        if (!inode->i_private) {
                inode_unlock(inode);
                return -ENODEV;
        }
        chip_seqops = (struct tpm_chip_seqops *)inode->i_private;
        seqops = chip_seqops->seqops;
        chip = chip_seqops->chip;
        get_device(&chip->dev);
        inode_unlock(inode);

        /* now register seq file */
        err = seq_open(file, seqops);
        if (!err) {
                seq = file->private_data;
                seq->private = chip;
        }

        return err;
}

static const struct file_operations tpm_bios_measurements_ops = {
        .owner = THIS_MODULE,
        .open = tpm_bios_measurements_open,
        .read = seq_read,
        .llseek = seq_lseek,
        .release = tpm_bios_measurements_release,
};

static int tpm_read_log(struct tpm_chip *chip)
{
        int rc;

        if (chip->log.bios_event_log != NULL) {
                dev_dbg(&chip->dev,
                        "%s: ERROR - event log already initialized\n",
                        __func__);
                return -EFAULT;
        }

        rc = tpm_read_log_acpi(chip);
        if (rc != -ENODEV)
                return rc;

        return tpm_read_log_of(chip);
}

/*
 * tpm_bios_log_setup() - Read the event log from the firmware
 * @chip: TPM chip to use.
 *
 * If an event log is found then the securityfs files are setup to
 * export it to userspace, otherwise nothing is done.
 *
 * Returns -ENODEV if the firmware has no event log or securityfs is not
 * supported.
 */
int tpm_bios_log_setup(struct tpm_chip *chip)
{
        const char *name = dev_name(&chip->dev);
        unsigned int cnt;
        int rc = 0;

        rc = tpm_read_log(chip);
        if (rc)
                return rc;

        cnt = 0;
        chip->bios_dir[cnt] = securityfs_create_dir(name, NULL);
        /* NOTE: securityfs_create_dir can return ENODEV if securityfs is
         * compiled out. The caller should ignore the ENODEV return code.
         */
        if (IS_ERR(chip->bios_dir[cnt]))
                goto err;
        cnt++;

        chip->bin_log_seqops.chip = chip;
        if (chip->flags & TPM_CHIP_FLAG_TPM2)
                chip->bin_log_seqops.seqops =
                        &tpm2_binary_b_measurements_seqops;
        else
                chip->bin_log_seqops.seqops =
                        &tpm_binary_b_measurements_seqops;


        chip->bios_dir[cnt] =
            securityfs_create_file("binary_bios_measurements",
                                   0440, chip->bios_dir[0],
                                   (void *)&chip->bin_log_seqops,
                                   &tpm_bios_measurements_ops);
        if (IS_ERR(chip->bios_dir[cnt]))
                goto err;
        cnt++;

        if (!(chip->flags & TPM_CHIP_FLAG_TPM2)) {

                chip->ascii_log_seqops.chip = chip;
                chip->ascii_log_seqops.seqops =
                        &tpm_ascii_b_measurements_seqops;

                chip->bios_dir[cnt] =
                        securityfs_create_file("ascii_bios_measurements",
                                               0440, chip->bios_dir[0],
                                               (void *)&chip->ascii_log_seqops,
                                               &tpm_bios_measurements_ops);
                if (IS_ERR(chip->bios_dir[cnt]))
                        goto err;
                cnt++;
        }

        return 0;

err:
        rc = PTR_ERR(chip->bios_dir[cnt]);
        chip->bios_dir[cnt] = NULL;
        tpm_bios_log_teardown(chip);
        return rc;
}

void tpm_bios_log_teardown(struct tpm_chip *chip)
{
        int i;
        struct inode *inode;

        /* securityfs_remove currently doesn't take care of handling sync
         * between removal and opening of pseudo files. To handle this, a
         * workaround is added by making i_private = NULL here during removal
         * and to check it during open(), both within inode_lock()/unlock().
         * This design ensures that open() either safely gets kref or fails.
         */
        for (i = (TPM_NUM_EVENT_LOG_FILES - 1); i >= 0; i--) {
                if (chip->bios_dir[i]) {
                        inode = d_inode(chip->bios_dir[i]);
                        inode_lock(inode);
                        inode->i_private = NULL;
                        inode_unlock(inode);
                        securityfs_remove(chip->bios_dir[i]);
                }
        }
}