// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2021 Microsoft Corporation
 *
 * Author: Tushar Sugandhi <tusharsu@linux.microsoft.com>
 *
 * Enables IMA measurements for DM targets
 */

#include "dm-core.h"
#include "dm-ima.h"

#include <linux/ima.h>
#include <linux/sched/mm.h>
#include <crypto/hash.h>
#include <linux/crypto.h>
#include <crypto/hash_info.h>

#define DM_MSG_PREFIX "ima"

/*
 * Internal function to prefix separator characters in input buffer with escape
 * character, so that they don't interfere with the construction of key-value pairs,
 * and clients can split the key1=val1,key2=val2,key3=val3; pairs properly.
 */
static void fix_separator_chars(char **buf)
{
        int l = strlen(*buf);
        int i, j, sp = 0;

        for (i = 0; i < l; i++)
                if ((*buf)[i] == '\\' || (*buf)[i] == ';' || (*buf)[i] == '=' || (*buf)[i] == ',')
                        sp++;

        if (!sp)
                return;

        for (i = l-1, j = i+sp; i >= 0; i--) {
                (*buf)[j--] = (*buf)[i];
                if ((*buf)[i] == '\\' || (*buf)[i] == ';' || (*buf)[i] == '=' || (*buf)[i] == ',')
                        (*buf)[j--] = '\\';
        }
}

/*
 * Internal function to allocate memory for IMA measurements.
 */
static void *dm_ima_alloc(size_t len, bool noio)
{
        unsigned int noio_flag;
        void *ptr;

        if (noio)
                noio_flag = memalloc_noio_save();

        ptr = kzalloc(len, GFP_KERNEL);

        if (noio)
                memalloc_noio_restore(noio_flag);

        return ptr;
}

/*
 * Internal function to allocate and copy name and uuid for IMA measurements.
 */
static int dm_ima_alloc_and_copy_name_uuid(struct mapped_device *md, char **dev_name,
                                           char **dev_uuid, bool noio)
{
        int r;
        *dev_name = dm_ima_alloc(DM_NAME_LEN*2, noio);
        if (!(*dev_name)) {
                r = -ENOMEM;
                goto error;
        }

        *dev_uuid = dm_ima_alloc(DM_UUID_LEN*2, noio);
        if (!(*dev_uuid)) {
                r = -ENOMEM;
                goto error;
        }

        r = dm_copy_name_and_uuid(md, *dev_name, *dev_uuid);
        if (r)
                goto error;

        fix_separator_chars(dev_name);
        fix_separator_chars(dev_uuid);

        return 0;
error:
        kfree(*dev_name);
        kfree(*dev_uuid);
        *dev_name = NULL;
        *dev_uuid = NULL;
        return r;
}

/*
 * Internal function to allocate and copy device data for IMA measurements.
 */
static int dm_ima_alloc_and_copy_device_data(struct mapped_device *md, char **device_data,
                                             unsigned int num_targets, bool noio)
{
        char *dev_name = NULL, *dev_uuid = NULL;
        int r;

        r = dm_ima_alloc_and_copy_name_uuid(md, &dev_name, &dev_uuid, noio);
        if (r)
                return r;

        *device_data = dm_ima_alloc(DM_IMA_DEVICE_BUF_LEN, noio);
        if (!(*device_data)) {
                r = -ENOMEM;
                goto error;
        }

        scnprintf(*device_data, DM_IMA_DEVICE_BUF_LEN,
                  "name=%s,uuid=%s,major=%d,minor=%d,minor_count=%d,num_targets=%u;",
                  dev_name, dev_uuid, md->disk->major, md->disk->first_minor,
                  md->disk->minors, num_targets);
error:
        kfree(dev_name);
        kfree(dev_uuid);
        return r;
}

/*
 * Internal wrapper function to call IMA to measure DM data.
 */
static void dm_ima_measure_data(const char *event_name, const void *buf, size_t buf_len,
                                bool noio)
{
        unsigned int noio_flag;

        if (noio)
                noio_flag = memalloc_noio_save();

        ima_measure_critical_data(DM_NAME, event_name, buf, buf_len,
                                  false, NULL, 0);

        if (noio)
                memalloc_noio_restore(noio_flag);
}

/*
 * Internal function to allocate and copy current device capacity for IMA measurements.
 */
static int dm_ima_alloc_and_copy_capacity_str(struct mapped_device *md, char **capacity_str,
                                              bool noio)
{
        sector_t capacity;

        capacity = get_capacity(md->disk);

        *capacity_str = dm_ima_alloc(DM_IMA_DEVICE_CAPACITY_BUF_LEN, noio);
        if (!(*capacity_str))
                return -ENOMEM;

        return scnprintf(*capacity_str, DM_IMA_DEVICE_BUF_LEN, "current_device_capacity=%llu;",
                         capacity);
}

/*
 * Initialize/reset the dm ima related data structure variables.
 */
void dm_ima_reset_data(struct mapped_device *md)
{
        memset(&(md->ima), 0, sizeof(md->ima));
        md->ima.dm_version_str_len = strlen(DM_IMA_VERSION_STR);
}

/*
 * Build up the IMA data for each target, and finally measure.
 */
void dm_ima_measure_on_table_load(struct dm_table *table, unsigned int status_flags)
{
        size_t device_data_buf_len, target_metadata_buf_len, target_data_buf_len, l = 0;
        char *target_metadata_buf = NULL, *target_data_buf = NULL, *digest_buf = NULL;
        char *ima_buf = NULL, *device_data_buf = NULL;
        int digest_size, last_target_measured = -1, r;
        status_type_t type = STATUSTYPE_IMA;
        size_t cur_total_buf_len = 0;
        unsigned int num_targets, i;
        SHASH_DESC_ON_STACK(shash, NULL);
        struct crypto_shash *tfm = NULL;
        u8 *digest = NULL;
        bool noio = false;
        /*
         * In below hash_alg_prefix_len assignment +1 is for the additional char (':'),
         * when prefixing the hash value with the hash algorithm name. e.g. sha256:<hash_value>.
         */
        const size_t hash_alg_prefix_len = strlen(DM_IMA_TABLE_HASH_ALG) + 1;
        char table_load_event_name[] = "dm_table_load";

        ima_buf = dm_ima_alloc(DM_IMA_MEASUREMENT_BUF_LEN, noio);
        if (!ima_buf)
                return;

        target_metadata_buf = dm_ima_alloc(DM_IMA_TARGET_METADATA_BUF_LEN, noio);
        if (!target_metadata_buf)
                goto error;

        target_data_buf = dm_ima_alloc(DM_IMA_TARGET_DATA_BUF_LEN, noio);
        if (!target_data_buf)
                goto error;

        num_targets = table->num_targets;

        if (dm_ima_alloc_and_copy_device_data(table->md, &device_data_buf, num_targets, noio))
                goto error;

        tfm = crypto_alloc_shash(DM_IMA_TABLE_HASH_ALG, 0, 0);
        if (IS_ERR(tfm))
                goto error;

        shash->tfm = tfm;
        digest_size = crypto_shash_digestsize(tfm);
        digest = dm_ima_alloc(digest_size, noio);
        if (!digest)
                goto error;

        r = crypto_shash_init(shash);
        if (r)
                goto error;

        memcpy(ima_buf + l, DM_IMA_VERSION_STR, table->md->ima.dm_version_str_len);
        l += table->md->ima.dm_version_str_len;

        device_data_buf_len = strlen(device_data_buf);
        memcpy(ima_buf + l, device_data_buf, device_data_buf_len);
        l += device_data_buf_len;

        for (i = 0; i < num_targets; i++) {
                struct dm_target *ti = dm_table_get_target(table, i);

                last_target_measured = 0;

                /*
                 * First retrieve the target metadata.
                 */
                target_metadata_buf_len =
                        scnprintf(target_metadata_buf,
                                  DM_IMA_TARGET_METADATA_BUF_LEN,
                                  "target_index=%d,target_begin=%llu,target_len=%llu,",
                                  i, ti->begin, ti->len);

                /*
                 * Then retrieve the actual target data.
                 */
                if (ti->type->status)
                        ti->type->status(ti, type, status_flags, target_data_buf,
                                         DM_IMA_TARGET_DATA_BUF_LEN);
                else
                        target_data_buf[0] = '\0';

                target_data_buf_len = strlen(target_data_buf);

                /*
                 * Check if the total data can fit into the IMA buffer.
                 */
                cur_total_buf_len = l + target_metadata_buf_len + target_data_buf_len;

                /*
                 * IMA measurements for DM targets are best-effort.
                 * If the total data buffered so far, including the current target,
                 * is too large to fit into DM_IMA_MEASUREMENT_BUF_LEN, measure what
                 * we have in the current buffer, and continue measuring the remaining
                 * targets by prefixing the device metadata again.
                 */
                if (unlikely(cur_total_buf_len >= DM_IMA_MEASUREMENT_BUF_LEN)) {
                        dm_ima_measure_data(table_load_event_name, ima_buf, l, noio);
                        r = crypto_shash_update(shash, (const u8 *)ima_buf, l);
                        if (r < 0)
                                goto error;

                        memset(ima_buf, 0, DM_IMA_MEASUREMENT_BUF_LEN);
                        l = 0;

                        /*
                         * Each new "dm_table_load" entry in IMA log should have device data
                         * prefix, so that multiple records from the same "dm_table_load" for
                         * a given device can be linked together.
                         */
                        memcpy(ima_buf + l, DM_IMA_VERSION_STR, table->md->ima.dm_version_str_len);
                        l += table->md->ima.dm_version_str_len;

                        memcpy(ima_buf + l, device_data_buf, device_data_buf_len);
                        l += device_data_buf_len;

                        /*
                         * If this iteration of the for loop turns out to be the last target
                         * in the table, dm_ima_measure_data("dm_table_load", ...) doesn't need
                         * to be called again, just the hash needs to be finalized.
                         * "last_target_measured" tracks this state.
                         */
                        last_target_measured = 1;
                }

                /*
                 * Fill-in all the target metadata, so that multiple targets for the same
                 * device can be linked together.
                 */
                memcpy(ima_buf + l, target_metadata_buf, target_metadata_buf_len);
                l += target_metadata_buf_len;

                memcpy(ima_buf + l, target_data_buf, target_data_buf_len);
                l += target_data_buf_len;
        }

        if (!last_target_measured) {
                dm_ima_measure_data(table_load_event_name, ima_buf, l, noio);

                r = crypto_shash_update(shash, (const u8 *)ima_buf, l);
                if (r < 0)
                        goto error;
        }

        /*
         * Finalize the table hash, and store it in table->md->ima.inactive_table.hash,
         * so that the table data can be verified against the future device state change
         * events, e.g. resume, rename, remove, table-clear etc.
         */
        r = crypto_shash_final(shash, digest);
        if (r < 0)
                goto error;

        digest_buf = dm_ima_alloc((digest_size*2) + hash_alg_prefix_len + 1, noio);

        if (!digest_buf)
                goto error;

        snprintf(digest_buf, hash_alg_prefix_len + 1, "%s:", DM_IMA_TABLE_HASH_ALG);

        for (i = 0; i < digest_size; i++)
                snprintf((digest_buf + hash_alg_prefix_len + (i*2)), 3, "%02x", digest[i]);

        if (table->md->ima.active_table.hash != table->md->ima.inactive_table.hash)
                kfree(table->md->ima.inactive_table.hash);

        table->md->ima.inactive_table.hash = digest_buf;
        table->md->ima.inactive_table.hash_len = strlen(digest_buf);
        table->md->ima.inactive_table.num_targets = num_targets;

        if (table->md->ima.active_table.device_metadata !=
            table->md->ima.inactive_table.device_metadata)
                kfree(table->md->ima.inactive_table.device_metadata);

        table->md->ima.inactive_table.device_metadata = device_data_buf;
        table->md->ima.inactive_table.device_metadata_len = device_data_buf_len;

        goto exit;
error:
        kfree(digest_buf);
        kfree(device_data_buf);
exit:
        kfree(digest);
        if (tfm)
                crypto_free_shash(tfm);
        kfree(ima_buf);
        kfree(target_metadata_buf);
        kfree(target_data_buf);
}

/*
 * Measure IMA data on device resume.
 */
void dm_ima_measure_on_device_resume(struct mapped_device *md, bool swap)
{
        char *device_table_data, *dev_name = NULL, *dev_uuid = NULL, *capacity_str = NULL;
        char active[] = "active_table_hash=";
        unsigned int active_len = strlen(active);
        unsigned int l = 0;
        bool noio = true;
        bool nodata = true;
        int capacity_len;

        device_table_data = dm_ima_alloc(DM_IMA_DEVICE_BUF_LEN, noio);
        if (!device_table_data)
                return;

        capacity_len = dm_ima_alloc_and_copy_capacity_str(md, &capacity_str, noio);
        if (capacity_len < 0)
                goto error;

        memcpy(device_table_data + l, DM_IMA_VERSION_STR, md->ima.dm_version_str_len);
        l += md->ima.dm_version_str_len;

        if (swap) {
                if (md->ima.active_table.hash != md->ima.inactive_table.hash)
                        kfree(md->ima.active_table.hash);

                md->ima.active_table.hash = NULL;
                md->ima.active_table.hash_len = 0;

                if (md->ima.active_table.device_metadata !=
                    md->ima.inactive_table.device_metadata)
                        kfree(md->ima.active_table.device_metadata);

                md->ima.active_table.device_metadata = NULL;
                md->ima.active_table.device_metadata_len = 0;
                md->ima.active_table.num_targets = 0;

                if (md->ima.inactive_table.hash) {
                        md->ima.active_table.hash = md->ima.inactive_table.hash;
                        md->ima.active_table.hash_len = md->ima.inactive_table.hash_len;
                        md->ima.inactive_table.hash = NULL;
                        md->ima.inactive_table.hash_len = 0;
                }

                if (md->ima.inactive_table.device_metadata) {
                        md->ima.active_table.device_metadata =
                                md->ima.inactive_table.device_metadata;
                        md->ima.active_table.device_metadata_len =
                                md->ima.inactive_table.device_metadata_len;
                        md->ima.active_table.num_targets = md->ima.inactive_table.num_targets;
                        md->ima.inactive_table.device_metadata = NULL;
                        md->ima.inactive_table.device_metadata_len = 0;
                        md->ima.inactive_table.num_targets = 0;
                }
        }

        if (md->ima.active_table.device_metadata) {
                memcpy(device_table_data + l, md->ima.active_table.device_metadata,
                       md->ima.active_table.device_metadata_len);
                l += md->ima.active_table.device_metadata_len;

                nodata = false;
        }

        if (md->ima.active_table.hash) {
                memcpy(device_table_data + l, active, active_len);
                l += active_len;

                memcpy(device_table_data + l, md->ima.active_table.hash,
                       md->ima.active_table.hash_len);
                l += md->ima.active_table.hash_len;

                memcpy(device_table_data + l, ";", 1);
                l++;

                nodata = false;
        }

        if (nodata) {
                if (dm_ima_alloc_and_copy_name_uuid(md, &dev_name, &dev_uuid, noio))
                        goto error;

                l = scnprintf(device_table_data, DM_IMA_DEVICE_BUF_LEN,
                              "%sname=%s,uuid=%s;device_resume=no_data;",
                              DM_IMA_VERSION_STR, dev_name, dev_uuid);
        }

        memcpy(device_table_data + l, capacity_str, capacity_len);
        l += capacity_len;

        dm_ima_measure_data("dm_device_resume", device_table_data, l, noio);

        kfree(dev_name);
        kfree(dev_uuid);
error:
        kfree(capacity_str);
        kfree(device_table_data);
}

/*
 * Measure IMA data on remove.
 */
void dm_ima_measure_on_device_remove(struct mapped_device *md, bool remove_all)
{
        char *device_table_data, *dev_name = NULL, *dev_uuid = NULL, *capacity_str = NULL;
        char active_table_str[] = "active_table_hash=";
        char inactive_table_str[] = "inactive_table_hash=";
        char device_active_str[] = "device_active_metadata=";
        char device_inactive_str[] = "device_inactive_metadata=";
        char remove_all_str[] = "remove_all=";
        unsigned int active_table_len = strlen(active_table_str);
        unsigned int inactive_table_len = strlen(inactive_table_str);
        unsigned int device_active_len = strlen(device_active_str);
        unsigned int device_inactive_len = strlen(device_inactive_str);
        unsigned int remove_all_len = strlen(remove_all_str);
        unsigned int l = 0;
        bool noio = true;
        bool nodata = true;
        int capacity_len;

        device_table_data = dm_ima_alloc(DM_IMA_DEVICE_BUF_LEN*2, noio);
        if (!device_table_data)
                goto exit;

        capacity_len = dm_ima_alloc_and_copy_capacity_str(md, &capacity_str, noio);
        if (capacity_len < 0) {
                kfree(device_table_data);
                goto exit;
        }

        memcpy(device_table_data + l, DM_IMA_VERSION_STR, md->ima.dm_version_str_len);
        l += md->ima.dm_version_str_len;

        if (md->ima.active_table.device_metadata) {
                memcpy(device_table_data + l, device_active_str, device_active_len);
                l += device_active_len;

                memcpy(device_table_data + l, md->ima.active_table.device_metadata,
                       md->ima.active_table.device_metadata_len);
                l += md->ima.active_table.device_metadata_len;

                nodata = false;
        }

        if (md->ima.inactive_table.device_metadata) {
                memcpy(device_table_data + l, device_inactive_str, device_inactive_len);
                l += device_inactive_len;

                memcpy(device_table_data + l, md->ima.inactive_table.device_metadata,
                       md->ima.inactive_table.device_metadata_len);
                l += md->ima.inactive_table.device_metadata_len;

                nodata = false;
        }

        if (md->ima.active_table.hash) {
                memcpy(device_table_data + l, active_table_str, active_table_len);
                l += active_table_len;

                memcpy(device_table_data + l, md->ima.active_table.hash,
                           md->ima.active_table.hash_len);
                l += md->ima.active_table.hash_len;

                memcpy(device_table_data + l, ",", 1);
                l++;

                nodata = false;
        }

        if (md->ima.inactive_table.hash) {
                memcpy(device_table_data + l, inactive_table_str, inactive_table_len);
                l += inactive_table_len;

                memcpy(device_table_data + l, md->ima.inactive_table.hash,
                       md->ima.inactive_table.hash_len);
                l += md->ima.inactive_table.hash_len;

                memcpy(device_table_data + l, ",", 1);
                l++;

                nodata = false;
        }
        /*
         * In case both active and inactive tables, and corresponding
         * device metadata is cleared/missing - record the name and uuid
         * in IMA measurements.
         */
        if (nodata) {
                if (dm_ima_alloc_and_copy_name_uuid(md, &dev_name, &dev_uuid, noio))
                        goto error;

                l = scnprintf(device_table_data, DM_IMA_DEVICE_BUF_LEN,
                              "%sname=%s,uuid=%s;device_remove=no_data;",
                              DM_IMA_VERSION_STR, dev_name, dev_uuid);
        }

        memcpy(device_table_data + l, remove_all_str, remove_all_len);
        l += remove_all_len;
        memcpy(device_table_data + l, remove_all ? "y;" : "n;", 2);
        l += 2;

        memcpy(device_table_data + l, capacity_str, capacity_len);
        l += capacity_len;

        dm_ima_measure_data("dm_device_remove", device_table_data, l, noio);

error:
        kfree(device_table_data);
        kfree(capacity_str);
exit:
        kfree(md->ima.active_table.device_metadata);

        if (md->ima.active_table.device_metadata !=
            md->ima.inactive_table.device_metadata)
                kfree(md->ima.inactive_table.device_metadata);

        kfree(md->ima.active_table.hash);

        if (md->ima.active_table.hash != md->ima.inactive_table.hash)
                kfree(md->ima.inactive_table.hash);

        dm_ima_reset_data(md);

        kfree(dev_name);
        kfree(dev_uuid);
}

/*
 * Measure ima data on table clear.
 */
void dm_ima_measure_on_table_clear(struct mapped_device *md, bool new_map)
{
        unsigned int l = 0;
        char *device_table_data = NULL, *dev_name = NULL, *dev_uuid = NULL, *capacity_str = NULL;
        char inactive_str[] = "inactive_table_hash=";
        unsigned int inactive_len = strlen(inactive_str);
        bool noio = true;
        bool nodata = true;
        int capacity_len;

        device_table_data = dm_ima_alloc(DM_IMA_DEVICE_BUF_LEN, noio);
        if (!device_table_data)
                return;

        capacity_len = dm_ima_alloc_and_copy_capacity_str(md, &capacity_str, noio);
        if (capacity_len < 0)
                goto error1;

        memcpy(device_table_data + l, DM_IMA_VERSION_STR, md->ima.dm_version_str_len);
        l += md->ima.dm_version_str_len;

        if (md->ima.inactive_table.device_metadata_len &&
            md->ima.inactive_table.hash_len) {
                memcpy(device_table_data + l, md->ima.inactive_table.device_metadata,
                       md->ima.inactive_table.device_metadata_len);
                l += md->ima.inactive_table.device_metadata_len;

                memcpy(device_table_data + l, inactive_str, inactive_len);
                l += inactive_len;

                memcpy(device_table_data + l, md->ima.inactive_table.hash,
                           md->ima.inactive_table.hash_len);

                l += md->ima.inactive_table.hash_len;

                memcpy(device_table_data + l, ";", 1);
                l++;

                nodata = false;
        }

        if (nodata) {
                if (dm_ima_alloc_and_copy_name_uuid(md, &dev_name, &dev_uuid, noio))
                        goto error2;

                l = scnprintf(device_table_data, DM_IMA_DEVICE_BUF_LEN,
                              "%sname=%s,uuid=%s;table_clear=no_data;",
                              DM_IMA_VERSION_STR, dev_name, dev_uuid);
        }

        memcpy(device_table_data + l, capacity_str, capacity_len);
        l += capacity_len;

        dm_ima_measure_data("dm_table_clear", device_table_data, l, noio);

        if (new_map) {
                if (md->ima.inactive_table.hash &&
                    md->ima.inactive_table.hash != md->ima.active_table.hash)
                        kfree(md->ima.inactive_table.hash);

                md->ima.inactive_table.hash = NULL;
                md->ima.inactive_table.hash_len = 0;

                if (md->ima.inactive_table.device_metadata &&
                    md->ima.inactive_table.device_metadata != md->ima.active_table.device_metadata)
                        kfree(md->ima.inactive_table.device_metadata);

                md->ima.inactive_table.device_metadata = NULL;
                md->ima.inactive_table.device_metadata_len = 0;
                md->ima.inactive_table.num_targets = 0;

                if (md->ima.active_table.hash) {
                        md->ima.inactive_table.hash = md->ima.active_table.hash;
                        md->ima.inactive_table.hash_len = md->ima.active_table.hash_len;
                }

                if (md->ima.active_table.device_metadata) {
                        md->ima.inactive_table.device_metadata =
                                md->ima.active_table.device_metadata;
                        md->ima.inactive_table.device_metadata_len =
                                md->ima.active_table.device_metadata_len;
                        md->ima.inactive_table.num_targets =
                                md->ima.active_table.num_targets;
                }
        }

        kfree(dev_name);
        kfree(dev_uuid);
error2:
        kfree(capacity_str);
error1:
        kfree(device_table_data);
}

/*
 * Measure IMA data on device rename.
 */
void dm_ima_measure_on_device_rename(struct mapped_device *md)
{
        char *old_device_data = NULL, *new_device_data = NULL, *combined_device_data = NULL;
        char *new_dev_name = NULL, *new_dev_uuid = NULL, *capacity_str = NULL;
        bool noio = true;
        int len;

        if (dm_ima_alloc_and_copy_device_data(md, &new_device_data,
                                              md->ima.active_table.num_targets, noio))
                return;

        if (dm_ima_alloc_and_copy_name_uuid(md, &new_dev_name, &new_dev_uuid, noio))
                goto error;

        combined_device_data = dm_ima_alloc(DM_IMA_DEVICE_BUF_LEN * 2, noio);
        if (!combined_device_data)
                goto error;

        if (dm_ima_alloc_and_copy_capacity_str(md, &capacity_str, noio) < 0)
                goto error;

        old_device_data = md->ima.active_table.device_metadata;

        md->ima.active_table.device_metadata = new_device_data;
        md->ima.active_table.device_metadata_len = strlen(new_device_data);

        len = scnprintf(combined_device_data, DM_IMA_DEVICE_BUF_LEN * 2,
                        "%s%snew_name=%s,new_uuid=%s;%s", DM_IMA_VERSION_STR, old_device_data,
                        new_dev_name, new_dev_uuid, capacity_str);

        dm_ima_measure_data("dm_device_rename", combined_device_data, len, noio);

        goto exit;

error:
        kfree(new_device_data);
exit:
        kfree(capacity_str);
        kfree(combined_device_data);
        kfree(old_device_data);
        kfree(new_dev_name);
        kfree(new_dev_uuid);
}