diff options
Diffstat (limited to 'drivers/md/dm-ioctl.c')
| -rw-r--r-- | drivers/md/dm-ioctl.c | 2335 |
1 files changed, 2335 insertions, 0 deletions
diff --git a/drivers/md/dm-ioctl.c b/drivers/md/dm-ioctl.c new file mode 100644 index 0000000000..21ebb6c393 --- /dev/null +++ b/drivers/md/dm-ioctl.c @@ -0,0 +1,2335 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (C) 2001, 2002 Sistina Software (UK) Limited. + * Copyright (C) 2004 - 2006 Red Hat, Inc. All rights reserved. + * + * This file is released under the GPL. + */ + +#include "dm-core.h" +#include "dm-ima.h" +#include <linux/module.h> +#include <linux/vmalloc.h> +#include <linux/miscdevice.h> +#include <linux/sched/mm.h> +#include <linux/init.h> +#include <linux/wait.h> +#include <linux/slab.h> +#include <linux/rbtree.h> +#include <linux/dm-ioctl.h> +#include <linux/hdreg.h> +#include <linux/compat.h> +#include <linux/nospec.h> + +#include <linux/uaccess.h> +#include <linux/ima.h> + +#define DM_MSG_PREFIX "ioctl" +#define DM_DRIVER_EMAIL "dm-devel@redhat.com" + +struct dm_file { + /* + * poll will wait until the global event number is greater than + * this value. + */ + volatile unsigned int global_event_nr; +}; + +/* + *--------------------------------------------------------------- + * The ioctl interface needs to be able to look up devices by + * name or uuid. + *--------------------------------------------------------------- + */ +struct hash_cell { + struct rb_node name_node; + struct rb_node uuid_node; + bool name_set; + bool uuid_set; + + char *name; + char *uuid; + struct mapped_device *md; + struct dm_table *new_map; +}; + +struct vers_iter { + size_t param_size; + struct dm_target_versions *vers, *old_vers; + char *end; + uint32_t flags; +}; + + +static struct rb_root name_rb_tree = RB_ROOT; +static struct rb_root uuid_rb_tree = RB_ROOT; + +static void dm_hash_remove_all(bool keep_open_devices, bool mark_deferred, bool only_deferred); + +/* + * Guards access to both hash tables. + */ +static DECLARE_RWSEM(_hash_lock); + +/* + * Protects use of mdptr to obtain hash cell name and uuid from mapped device. + */ +static DEFINE_MUTEX(dm_hash_cells_mutex); + +static void dm_hash_exit(void) +{ + dm_hash_remove_all(false, false, false); +} + +/* + *--------------------------------------------------------------- + * Code for looking up a device by name + *--------------------------------------------------------------- + */ +static struct hash_cell *__get_name_cell(const char *str) +{ + struct rb_node *n = name_rb_tree.rb_node; + + while (n) { + struct hash_cell *hc = container_of(n, struct hash_cell, name_node); + int c; + + c = strcmp(hc->name, str); + if (!c) { + dm_get(hc->md); + return hc; + } + n = c >= 0 ? n->rb_left : n->rb_right; + } + + return NULL; +} + +static struct hash_cell *__get_uuid_cell(const char *str) +{ + struct rb_node *n = uuid_rb_tree.rb_node; + + while (n) { + struct hash_cell *hc = container_of(n, struct hash_cell, uuid_node); + int c; + + c = strcmp(hc->uuid, str); + if (!c) { + dm_get(hc->md); + return hc; + } + n = c >= 0 ? n->rb_left : n->rb_right; + } + + return NULL; +} + +static void __unlink_name(struct hash_cell *hc) +{ + if (hc->name_set) { + hc->name_set = false; + rb_erase(&hc->name_node, &name_rb_tree); + } +} + +static void __unlink_uuid(struct hash_cell *hc) +{ + if (hc->uuid_set) { + hc->uuid_set = false; + rb_erase(&hc->uuid_node, &uuid_rb_tree); + } +} + +static void __link_name(struct hash_cell *new_hc) +{ + struct rb_node **n, *parent; + + __unlink_name(new_hc); + + new_hc->name_set = true; + + n = &name_rb_tree.rb_node; + parent = NULL; + + while (*n) { + struct hash_cell *hc = container_of(*n, struct hash_cell, name_node); + int c; + + c = strcmp(hc->name, new_hc->name); + BUG_ON(!c); + parent = *n; + n = c >= 0 ? &hc->name_node.rb_left : &hc->name_node.rb_right; + } + + rb_link_node(&new_hc->name_node, parent, n); + rb_insert_color(&new_hc->name_node, &name_rb_tree); +} + +static void __link_uuid(struct hash_cell *new_hc) +{ + struct rb_node **n, *parent; + + __unlink_uuid(new_hc); + + new_hc->uuid_set = true; + + n = &uuid_rb_tree.rb_node; + parent = NULL; + + while (*n) { + struct hash_cell *hc = container_of(*n, struct hash_cell, uuid_node); + int c; + + c = strcmp(hc->uuid, new_hc->uuid); + BUG_ON(!c); + parent = *n; + n = c > 0 ? &hc->uuid_node.rb_left : &hc->uuid_node.rb_right; + } + + rb_link_node(&new_hc->uuid_node, parent, n); + rb_insert_color(&new_hc->uuid_node, &uuid_rb_tree); +} + +static struct hash_cell *__get_dev_cell(uint64_t dev) +{ + struct mapped_device *md; + struct hash_cell *hc; + + md = dm_get_md(huge_decode_dev(dev)); + if (!md) + return NULL; + + hc = dm_get_mdptr(md); + if (!hc) { + dm_put(md); + return NULL; + } + + return hc; +} + +/* + *--------------------------------------------------------------- + * Inserting, removing and renaming a device. + *--------------------------------------------------------------- + */ +static struct hash_cell *alloc_cell(const char *name, const char *uuid, + struct mapped_device *md) +{ + struct hash_cell *hc; + + hc = kmalloc(sizeof(*hc), GFP_KERNEL); + if (!hc) + return NULL; + + hc->name = kstrdup(name, GFP_KERNEL); + if (!hc->name) { + kfree(hc); + return NULL; + } + + if (!uuid) + hc->uuid = NULL; + + else { + hc->uuid = kstrdup(uuid, GFP_KERNEL); + if (!hc->uuid) { + kfree(hc->name); + kfree(hc); + return NULL; + } + } + + hc->name_set = hc->uuid_set = false; + hc->md = md; + hc->new_map = NULL; + return hc; +} + +static void free_cell(struct hash_cell *hc) +{ + if (hc) { + kfree(hc->name); + kfree(hc->uuid); + kfree(hc); + } +} + +/* + * The kdev_t and uuid of a device can never change once it is + * initially inserted. + */ +static int dm_hash_insert(const char *name, const char *uuid, struct mapped_device *md) +{ + struct hash_cell *cell, *hc; + + /* + * Allocate the new cells. + */ + cell = alloc_cell(name, uuid, md); + if (!cell) + return -ENOMEM; + + /* + * Insert the cell into both hash tables. + */ + down_write(&_hash_lock); + hc = __get_name_cell(name); + if (hc) { + dm_put(hc->md); + goto bad; + } + + __link_name(cell); + + if (uuid) { + hc = __get_uuid_cell(uuid); + if (hc) { + __unlink_name(cell); + dm_put(hc->md); + goto bad; + } + __link_uuid(cell); + } + dm_get(md); + mutex_lock(&dm_hash_cells_mutex); + dm_set_mdptr(md, cell); + mutex_unlock(&dm_hash_cells_mutex); + up_write(&_hash_lock); + + return 0; + + bad: + up_write(&_hash_lock); + free_cell(cell); + return -EBUSY; +} + +static struct dm_table *__hash_remove(struct hash_cell *hc) +{ + struct dm_table *table; + int srcu_idx; + + lockdep_assert_held(&_hash_lock); + + /* remove from the dev trees */ + __unlink_name(hc); + __unlink_uuid(hc); + mutex_lock(&dm_hash_cells_mutex); + dm_set_mdptr(hc->md, NULL); + mutex_unlock(&dm_hash_cells_mutex); + + table = dm_get_live_table(hc->md, &srcu_idx); + if (table) + dm_table_event(table); + dm_put_live_table(hc->md, srcu_idx); + + table = NULL; + if (hc->new_map) + table = hc->new_map; + dm_put(hc->md); + free_cell(hc); + + return table; +} + +static void dm_hash_remove_all(bool keep_open_devices, bool mark_deferred, bool only_deferred) +{ + int dev_skipped; + struct rb_node *n; + struct hash_cell *hc; + struct mapped_device *md; + struct dm_table *t; + +retry: + dev_skipped = 0; + + down_write(&_hash_lock); + + for (n = rb_first(&name_rb_tree); n; n = rb_next(n)) { + hc = container_of(n, struct hash_cell, name_node); + md = hc->md; + dm_get(md); + + if (keep_open_devices && + dm_lock_for_deletion(md, mark_deferred, only_deferred)) { + dm_put(md); + dev_skipped++; + continue; + } + + t = __hash_remove(hc); + + up_write(&_hash_lock); + + if (t) { + dm_sync_table(md); + dm_table_destroy(t); + } + dm_ima_measure_on_device_remove(md, true); + dm_put(md); + if (likely(keep_open_devices)) + dm_destroy(md); + else + dm_destroy_immediate(md); + + /* + * Some mapped devices may be using other mapped + * devices, so repeat until we make no further + * progress. If a new mapped device is created + * here it will also get removed. + */ + goto retry; + } + + up_write(&_hash_lock); + + if (dev_skipped) + DMWARN("remove_all left %d open device(s)", dev_skipped); +} + +/* + * Set the uuid of a hash_cell that isn't already set. + */ +static void __set_cell_uuid(struct hash_cell *hc, char *new_uuid) +{ + mutex_lock(&dm_hash_cells_mutex); + hc->uuid = new_uuid; + mutex_unlock(&dm_hash_cells_mutex); + + __link_uuid(hc); +} + +/* + * Changes the name of a hash_cell and returns the old name for + * the caller to free. + */ +static char *__change_cell_name(struct hash_cell *hc, char *new_name) +{ + char *old_name; + + /* + * Rename and move the name cell. + */ + __unlink_name(hc); + old_name = hc->name; + + mutex_lock(&dm_hash_cells_mutex); + hc->name = new_name; + mutex_unlock(&dm_hash_cells_mutex); + + __link_name(hc); + + return old_name; +} + +static struct mapped_device *dm_hash_rename(struct dm_ioctl *param, + const char *new) +{ + char *new_data, *old_name = NULL; + struct hash_cell *hc; + struct dm_table *table; + struct mapped_device *md; + unsigned int change_uuid = (param->flags & DM_UUID_FLAG) ? 1 : 0; + int srcu_idx; + + /* + * duplicate new. + */ + new_data = kstrdup(new, GFP_KERNEL); + if (!new_data) + return ERR_PTR(-ENOMEM); + + down_write(&_hash_lock); + + /* + * Is new free ? + */ + if (change_uuid) + hc = __get_uuid_cell(new); + else + hc = __get_name_cell(new); + + if (hc) { + DMERR("Unable to change %s on mapped device %s to one that already exists: %s", + change_uuid ? "uuid" : "name", + param->name, new); + dm_put(hc->md); + up_write(&_hash_lock); + kfree(new_data); + return ERR_PTR(-EBUSY); + } + + /* + * Is there such a device as 'old' ? + */ + hc = __get_name_cell(param->name); + if (!hc) { + DMERR("Unable to rename non-existent device, %s to %s%s", + param->name, change_uuid ? "uuid " : "", new); + up_write(&_hash_lock); + kfree(new_data); + return ERR_PTR(-ENXIO); + } + + /* + * Does this device already have a uuid? + */ + if (change_uuid && hc->uuid) { + DMERR("Unable to change uuid of mapped device %s to %s " + "because uuid is already set to %s", + param->name, new, hc->uuid); + dm_put(hc->md); + up_write(&_hash_lock); + kfree(new_data); + return ERR_PTR(-EINVAL); + } + + if (change_uuid) + __set_cell_uuid(hc, new_data); + else + old_name = __change_cell_name(hc, new_data); + + /* + * Wake up any dm event waiters. + */ + table = dm_get_live_table(hc->md, &srcu_idx); + if (table) + dm_table_event(table); + dm_put_live_table(hc->md, srcu_idx); + + if (!dm_kobject_uevent(hc->md, KOBJ_CHANGE, param->event_nr, false)) + param->flags |= DM_UEVENT_GENERATED_FLAG; + + md = hc->md; + + dm_ima_measure_on_device_rename(md); + + up_write(&_hash_lock); + kfree(old_name); + + return md; +} + +void dm_deferred_remove(void) +{ + dm_hash_remove_all(true, false, true); +} + +/* + *--------------------------------------------------------------- + * Implementation of the ioctl commands + *--------------------------------------------------------------- + */ +/* + * All the ioctl commands get dispatched to functions with this + * prototype. + */ +typedef int (*ioctl_fn)(struct file *filp, struct dm_ioctl *param, size_t param_size); + +static int remove_all(struct file *filp, struct dm_ioctl *param, size_t param_size) +{ + dm_hash_remove_all(true, !!(param->flags & DM_DEFERRED_REMOVE), false); + param->data_size = 0; + return 0; +} + +/* + * Round up the ptr to an 8-byte boundary. + */ +#define ALIGN_MASK 7 +static inline size_t align_val(size_t val) +{ + return (val + ALIGN_MASK) & ~ALIGN_MASK; +} +static inline void *align_ptr(void *ptr) +{ + return (void *)align_val((size_t)ptr); +} + +/* + * Retrieves the data payload buffer from an already allocated + * struct dm_ioctl. + */ +static void *get_result_buffer(struct dm_ioctl *param, size_t param_size, + size_t *len) +{ + param->data_start = align_ptr(param + 1) - (void *) param; + + if (param->data_start < param_size) + *len = param_size - param->data_start; + else + *len = 0; + + return ((void *) param) + param->data_start; +} + +static bool filter_device(struct hash_cell *hc, const char *pfx_name, const char *pfx_uuid) +{ + const char *val; + size_t val_len, pfx_len; + + val = hc->name; + val_len = strlen(val); + pfx_len = strnlen(pfx_name, DM_NAME_LEN); + if (pfx_len > val_len) + return false; + if (memcmp(val, pfx_name, pfx_len)) + return false; + + val = hc->uuid ? hc->uuid : ""; + val_len = strlen(val); + pfx_len = strnlen(pfx_uuid, DM_UUID_LEN); + if (pfx_len > val_len) + return false; + if (memcmp(val, pfx_uuid, pfx_len)) + return false; + + return true; +} + +static int list_devices(struct file *filp, struct dm_ioctl *param, size_t param_size) +{ + struct rb_node *n; + struct hash_cell *hc; + size_t len, needed = 0; + struct gendisk *disk; + struct dm_name_list *orig_nl, *nl, *old_nl = NULL; + uint32_t *event_nr; + + down_write(&_hash_lock); + + /* + * Loop through all the devices working out how much + * space we need. + */ + for (n = rb_first(&name_rb_tree); n; n = rb_next(n)) { + hc = container_of(n, struct hash_cell, name_node); + if (!filter_device(hc, param->name, param->uuid)) + continue; + needed += align_val(offsetof(struct dm_name_list, name) + strlen(hc->name) + 1); + needed += align_val(sizeof(uint32_t) * 2); + if (param->flags & DM_UUID_FLAG && hc->uuid) + needed += align_val(strlen(hc->uuid) + 1); + } + + /* + * Grab our output buffer. + */ + nl = orig_nl = get_result_buffer(param, param_size, &len); + if (len < needed || len < sizeof(nl->dev)) { + param->flags |= DM_BUFFER_FULL_FLAG; + goto out; + } + param->data_size = param->data_start + needed; + + nl->dev = 0; /* Flags no data */ + + /* + * Now loop through filling out the names. + */ + for (n = rb_first(&name_rb_tree); n; n = rb_next(n)) { + void *uuid_ptr; + + hc = container_of(n, struct hash_cell, name_node); + if (!filter_device(hc, param->name, param->uuid)) + continue; + if (old_nl) + old_nl->next = (uint32_t) ((void *) nl - + (void *) old_nl); + disk = dm_disk(hc->md); + nl->dev = huge_encode_dev(disk_devt(disk)); + nl->next = 0; + strcpy(nl->name, hc->name); + + old_nl = nl; + event_nr = align_ptr(nl->name + strlen(hc->name) + 1); + event_nr[0] = dm_get_event_nr(hc->md); + event_nr[1] = 0; + uuid_ptr = align_ptr(event_nr + 2); + if (param->flags & DM_UUID_FLAG) { + if (hc->uuid) { + event_nr[1] |= DM_NAME_LIST_FLAG_HAS_UUID; + strcpy(uuid_ptr, hc->uuid); + uuid_ptr = align_ptr(uuid_ptr + strlen(hc->uuid) + 1); + } else { + event_nr[1] |= DM_NAME_LIST_FLAG_DOESNT_HAVE_UUID; + } + } + nl = uuid_ptr; + } + /* + * If mismatch happens, security may be compromised due to buffer + * overflow, so it's better to crash. + */ + BUG_ON((char *)nl - (char *)orig_nl != needed); + + out: + up_write(&_hash_lock); + return 0; +} + +static void list_version_get_needed(struct target_type *tt, void *needed_param) +{ + size_t *needed = needed_param; + + *needed += sizeof(struct dm_target_versions); + *needed += strlen(tt->name) + 1; + *needed += ALIGN_MASK; +} + +static void list_version_get_info(struct target_type *tt, void *param) +{ + struct vers_iter *info = param; + + /* Check space - it might have changed since the first iteration */ + if ((char *)info->vers + sizeof(tt->version) + strlen(tt->name) + 1 > info->end) { + info->flags = DM_BUFFER_FULL_FLAG; + return; + } + + if (info->old_vers) + info->old_vers->next = (uint32_t) ((void *)info->vers - (void *)info->old_vers); + + info->vers->version[0] = tt->version[0]; + info->vers->version[1] = tt->version[1]; + info->vers->version[2] = tt->version[2]; + info->vers->next = 0; + strcpy(info->vers->name, tt->name); + + info->old_vers = info->vers; + info->vers = align_ptr((void *)(info->vers + 1) + strlen(tt->name) + 1); +} + +static int __list_versions(struct dm_ioctl *param, size_t param_size, const char *name) +{ + size_t len, needed = 0; + struct dm_target_versions *vers; + struct vers_iter iter_info; + struct target_type *tt = NULL; + + if (name) { + tt = dm_get_target_type(name); + if (!tt) + return -EINVAL; + } + + /* + * Loop through all the devices working out how much + * space we need. + */ + if (!tt) + dm_target_iterate(list_version_get_needed, &needed); + else + list_version_get_needed(tt, &needed); + + /* + * Grab our output buffer. + */ + vers = get_result_buffer(param, param_size, &len); + if (len < needed) { + param->flags |= DM_BUFFER_FULL_FLAG; + goto out; + } + param->data_size = param->data_start + needed; + + iter_info.param_size = param_size; + iter_info.old_vers = NULL; + iter_info.vers = vers; + iter_info.flags = 0; + iter_info.end = (char *)vers + needed; + + /* + * Now loop through filling out the names & versions. + */ + if (!tt) + dm_target_iterate(list_version_get_info, &iter_info); + else + list_version_get_info(tt, &iter_info); + param->flags |= iter_info.flags; + + out: + if (tt) + dm_put_target_type(tt); + return 0; +} + +static int list_versions(struct file *filp, struct dm_ioctl *param, size_t param_size) +{ + return __list_versions(param, param_size, NULL); +} + +static int get_target_version(struct file *filp, struct dm_ioctl *param, size_t param_size) +{ + return __list_versions(param, param_size, param->name); +} + +static int check_name(const char *name) +{ + if (strchr(name, '/')) { + DMERR("device name cannot contain '/'"); + return -EINVAL; + } + + if (strcmp(name, DM_CONTROL_NODE) == 0 || + strcmp(name, ".") == 0 || + strcmp(name, "..") == 0) { + DMERR("device name cannot be \"%s\", \".\", or \"..\"", DM_CONTROL_NODE); + return -EINVAL; + } + + return 0; +} + +/* + * On successful return, the caller must not attempt to acquire + * _hash_lock without first calling dm_put_live_table, because dm_table_destroy + * waits for this dm_put_live_table and could be called under this lock. + */ +static struct dm_table *dm_get_inactive_table(struct mapped_device *md, int *srcu_idx) +{ + struct hash_cell *hc; + struct dm_table *table = NULL; + + /* increment rcu count, we don't care about the table pointer */ + dm_get_live_table(md, srcu_idx); + + down_read(&_hash_lock); + hc = dm_get_mdptr(md); + if (!hc) { + DMERR("device has been removed from the dev hash table."); + goto out; + } + + table = hc->new_map; + +out: + up_read(&_hash_lock); + + return table; +} + +static struct dm_table *dm_get_live_or_inactive_table(struct mapped_device *md, + struct dm_ioctl *param, + int *srcu_idx) +{ + return (param->flags & DM_QUERY_INACTIVE_TABLE_FLAG) ? + dm_get_inactive_table(md, srcu_idx) : dm_get_live_table(md, srcu_idx); +} + +/* + * Fills in a dm_ioctl structure, ready for sending back to + * userland. + */ +static void __dev_status(struct mapped_device *md, struct dm_ioctl *param) +{ + struct gendisk *disk = dm_disk(md); + struct dm_table *table; + int srcu_idx; + + param->flags &= ~(DM_SUSPEND_FLAG | DM_READONLY_FLAG | + DM_ACTIVE_PRESENT_FLAG | DM_INTERNAL_SUSPEND_FLAG); + + if (dm_suspended_md(md)) + param->flags |= DM_SUSPEND_FLAG; + + if (dm_suspended_internally_md(md)) + param->flags |= DM_INTERNAL_SUSPEND_FLAG; + + if (dm_test_deferred_remove_flag(md)) + param->flags |= DM_DEFERRED_REMOVE; + + param->dev = huge_encode_dev(disk_devt(disk)); + + /* + * Yes, this will be out of date by the time it gets back + * to userland, but it is still very useful for + * debugging. + */ + param->open_count = dm_open_count(md); + + param->event_nr = dm_get_event_nr(md); + param->target_count = 0; + + table = dm_get_live_table(md, &srcu_idx); + if (table) { + if (!(param->flags & DM_QUERY_INACTIVE_TABLE_FLAG)) { + if (get_disk_ro(disk)) + param->flags |= DM_READONLY_FLAG; + param->target_count = table->num_targets; + } + + param->flags |= DM_ACTIVE_PRESENT_FLAG; + } + dm_put_live_table(md, srcu_idx); + + if (param->flags & DM_QUERY_INACTIVE_TABLE_FLAG) { + int srcu_idx; + + table = dm_get_inactive_table(md, &srcu_idx); + if (table) { + if (!(dm_table_get_mode(table) & BLK_OPEN_WRITE)) + param->flags |= DM_READONLY_FLAG; + param->target_count = table->num_targets; + } + dm_put_live_table(md, srcu_idx); + } +} + +static int dev_create(struct file *filp, struct dm_ioctl *param, size_t param_size) +{ + int r, m = DM_ANY_MINOR; + struct mapped_device *md; + + r = check_name(param->name); + if (r) + return r; + + if (param->flags & DM_PERSISTENT_DEV_FLAG) + m = MINOR(huge_decode_dev(param->dev)); + + r = dm_create(m, &md); + if (r) + return r; + + r = dm_hash_insert(param->name, *param->uuid ? param->uuid : NULL, md); + if (r) { + dm_put(md); + dm_destroy(md); + return r; + } + + param->flags &= ~DM_INACTIVE_PRESENT_FLAG; + + __dev_status(md, param); + + dm_put(md); + + return 0; +} + +/* + * Always use UUID for lookups if it's present, otherwise use name or dev. + */ +static struct hash_cell *__find_device_hash_cell(struct dm_ioctl *param) +{ + struct hash_cell *hc = NULL; + + if (*param->uuid) { + if (*param->name || param->dev) { + DMERR("Invalid ioctl structure: uuid %s, name %s, dev %llx", + param->uuid, param->name, (unsigned long long)param->dev); + return NULL; + } + + hc = __get_uuid_cell(param->uuid); + if (!hc) + return NULL; + } else if (*param->name) { + if (param->dev) { + DMERR("Invalid ioctl structure: name %s, dev %llx", + param->name, (unsigned long long)param->dev); + return NULL; + } + + hc = __get_name_cell(param->name); + if (!hc) + return NULL; + } else if (param->dev) { + hc = __get_dev_cell(param->dev); + if (!hc) + return NULL; + } else + return NULL; + + /* + * Sneakily write in both the name and the uuid + * while we have the cell. + */ + strscpy(param->name, hc->name, sizeof(param->name)); + if (hc->uuid) + strscpy(param->uuid, hc->uuid, sizeof(param->uuid)); + else + param->uuid[0] = '\0'; + + if (hc->new_map) + param->flags |= DM_INACTIVE_PRESENT_FLAG; + else + param->flags &= ~DM_INACTIVE_PRESENT_FLAG; + + return hc; +} + +static struct mapped_device *find_device(struct dm_ioctl *param) +{ + struct hash_cell *hc; + struct mapped_device *md = NULL; + + down_read(&_hash_lock); + hc = __find_device_hash_cell(param); + if (hc) + md = hc->md; + up_read(&_hash_lock); + + return md; +} + +static int dev_remove(struct file *filp, struct dm_ioctl *param, size_t param_size) +{ + struct hash_cell *hc; + struct mapped_device *md; + int r; + struct dm_table *t; + + down_write(&_hash_lock); + hc = __find_device_hash_cell(param); + + if (!hc) { + DMDEBUG_LIMIT("device doesn't appear to be in the dev hash table."); + up_write(&_hash_lock); + return -ENXIO; + } + + md = hc->md; + + /* + * Ensure the device is not open and nothing further can open it. + */ + r = dm_lock_for_deletion(md, !!(param->flags & DM_DEFERRED_REMOVE), false); + if (r) { + if (r == -EBUSY && param->flags & DM_DEFERRED_REMOVE) { + up_write(&_hash_lock); + dm_put(md); + return 0; + } + DMDEBUG_LIMIT("unable to remove open device %s", hc->name); + up_write(&_hash_lock); + dm_put(md); + return r; + } + + t = __hash_remove(hc); + up_write(&_hash_lock); + + if (t) { + dm_sync_table(md); + dm_table_destroy(t); + } + + param->flags &= ~DM_DEFERRED_REMOVE; + + dm_ima_measure_on_device_remove(md, false); + + if (!dm_kobject_uevent(md, KOBJ_REMOVE, param->event_nr, false)) + param->flags |= DM_UEVENT_GENERATED_FLAG; + + dm_put(md); + dm_destroy(md); + return 0; +} + +/* + * Check a string doesn't overrun the chunk of + * memory we copied from userland. + */ +static int invalid_str(char *str, void *end) +{ + while ((void *) str < end) + if (!*str++) + return 0; + + return -EINVAL; +} + +static int dev_rename(struct file *filp, struct dm_ioctl *param, size_t param_size) +{ + int r; + char *new_data = (char *) param + param->data_start; + struct mapped_device *md; + unsigned int change_uuid = (param->flags & DM_UUID_FLAG) ? 1 : 0; + + if (new_data < param->data || + invalid_str(new_data, (void *) param + param_size) || !*new_data || + strlen(new_data) > (change_uuid ? DM_UUID_LEN - 1 : DM_NAME_LEN - 1)) { + DMERR("Invalid new mapped device name or uuid string supplied."); + return -EINVAL; + } + + if (!change_uuid) { + r = check_name(new_data); + if (r) + return r; + } + + md = dm_hash_rename(param, new_data); + if (IS_ERR(md)) + return PTR_ERR(md); + + __dev_status(md, param); + dm_put(md); + + return 0; +} + +static int dev_set_geometry(struct file *filp, struct dm_ioctl *param, size_t param_size) +{ + int r = -EINVAL, x; + struct mapped_device *md; + struct hd_geometry geometry; + unsigned long indata[4]; + char *geostr = (char *) param + param->data_start; + char dummy; + + md = find_device(param); + if (!md) + return -ENXIO; + + if (geostr < param->data || + invalid_str(geostr, (void *) param + param_size)) { + DMERR("Invalid geometry supplied."); + goto out; + } + + x = sscanf(geostr, "%lu %lu %lu %lu%c", indata, + indata + 1, indata + 2, indata + 3, &dummy); + + if (x != 4) { + DMERR("Unable to interpret geometry settings."); + goto out; + } + + if (indata[0] > 65535 || indata[1] > 255 || indata[2] > 255) { + DMERR("Geometry exceeds range limits."); + goto out; + } + + geometry.cylinders = indata[0]; + geometry.heads = indata[1]; + geometry.sectors = indata[2]; + geometry.start = indata[3]; + + r = dm_set_geometry(md, &geometry); + + param->data_size = 0; + +out: + dm_put(md); + return r; +} + +static int do_suspend(struct dm_ioctl *param) +{ + int r = 0; + unsigned int suspend_flags = DM_SUSPEND_LOCKFS_FLAG; + struct mapped_device *md; + + md = find_device(param); + if (!md) + return -ENXIO; + + if (param->flags & DM_SKIP_LOCKFS_FLAG) + suspend_flags &= ~DM_SUSPEND_LOCKFS_FLAG; + if (param->flags & DM_NOFLUSH_FLAG) + suspend_flags |= DM_SUSPEND_NOFLUSH_FLAG; + + if (!dm_suspended_md(md)) { + r = dm_suspend(md, suspend_flags); + if (r) + goto out; + } + + __dev_status(md, param); + +out: + dm_put(md); + + return r; +} + +static int do_resume(struct dm_ioctl *param) +{ + int r = 0; + unsigned int suspend_flags = DM_SUSPEND_LOCKFS_FLAG; + struct hash_cell *hc; + struct mapped_device *md; + struct dm_table *new_map, *old_map = NULL; + bool need_resize_uevent = false; + + down_write(&_hash_lock); + + hc = __find_device_hash_cell(param); + if (!hc) { + DMDEBUG_LIMIT("device doesn't appear to be in the dev hash table."); + up_write(&_hash_lock); + return -ENXIO; + } + + md = hc->md; + + new_map = hc->new_map; + hc->new_map = NULL; + param->flags &= ~DM_INACTIVE_PRESENT_FLAG; + + up_write(&_hash_lock); + + /* Do we need to load a new map ? */ + if (new_map) { + sector_t old_size, new_size; + + /* Suspend if it isn't already suspended */ + if (param->flags & DM_SKIP_LOCKFS_FLAG) + suspend_flags &= ~DM_SUSPEND_LOCKFS_FLAG; + if (param->flags & DM_NOFLUSH_FLAG) + suspend_flags |= DM_SUSPEND_NOFLUSH_FLAG; + if (!dm_suspended_md(md)) + dm_suspend(md, suspend_flags); + + old_size = dm_get_size(md); + old_map = dm_swap_table(md, new_map); + if (IS_ERR(old_map)) { + dm_sync_table(md); + dm_table_destroy(new_map); + dm_put(md); + return PTR_ERR(old_map); + } + new_size = dm_get_size(md); + if (old_size && new_size && old_size != new_size) + need_resize_uevent = true; + + if (dm_table_get_mode(new_map) & BLK_OPEN_WRITE) + set_disk_ro(dm_disk(md), 0); + else + set_disk_ro(dm_disk(md), 1); + } + + if (dm_suspended_md(md)) { + r = dm_resume(md); + if (!r) { + dm_ima_measure_on_device_resume(md, new_map ? true : false); + + if (!dm_kobject_uevent(md, KOBJ_CHANGE, param->event_nr, need_resize_uevent)) + param->flags |= DM_UEVENT_GENERATED_FLAG; + } + } + + /* + * Since dm_swap_table synchronizes RCU, nobody should be in + * read-side critical section already. + */ + if (old_map) + dm_table_destroy(old_map); + + if (!r) + __dev_status(md, param); + + dm_put(md); + return r; +} + +/* + * Set or unset the suspension state of a device. + * If the device already is in the requested state we just return its status. + */ +static int dev_suspend(struct file *filp, struct dm_ioctl *param, size_t param_size) +{ + if (param->flags & DM_SUSPEND_FLAG) + return do_suspend(param); + + return do_resume(param); +} + +/* + * Copies device info back to user space, used by + * the create and info ioctls. + */ +static int dev_status(struct file *filp, struct dm_ioctl *param, size_t param_size) +{ + struct mapped_device *md; + + md = find_device(param); + if (!md) + return -ENXIO; + + __dev_status(md, param); + dm_put(md); + + return 0; +} + +/* + * Build up the status struct for each target + */ +static void retrieve_status(struct dm_table *table, + struct dm_ioctl *param, size_t param_size) +{ + unsigned int i, num_targets; + struct dm_target_spec *spec; + char *outbuf, *outptr; + status_type_t type; + size_t remaining, len, used = 0; + unsigned int status_flags = 0; + + outptr = outbuf = get_result_buffer(param, param_size, &len); + + if (param->flags & DM_STATUS_TABLE_FLAG) + type = STATUSTYPE_TABLE; + else if (param->flags & DM_IMA_MEASUREMENT_FLAG) + type = STATUSTYPE_IMA; + else + type = STATUSTYPE_INFO; + + /* Get all the target info */ + num_targets = table->num_targets; + for (i = 0; i < num_targets; i++) { + struct dm_target *ti = dm_table_get_target(table, i); + size_t l; + + remaining = len - (outptr - outbuf); + if (remaining <= sizeof(struct dm_target_spec)) { + param->flags |= DM_BUFFER_FULL_FLAG; + break; + } + + spec = (struct dm_target_spec *) outptr; + + spec->status = 0; + spec->sector_start = ti->begin; + spec->length = ti->len; + strncpy(spec->target_type, ti->type->name, + sizeof(spec->target_type) - 1); + + outptr += sizeof(struct dm_target_spec); + remaining = len - (outptr - outbuf); + if (remaining <= 0) { + param->flags |= DM_BUFFER_FULL_FLAG; + break; + } + + /* Get the status/table string from the target driver */ + if (ti->type->status) { + if (param->flags & DM_NOFLUSH_FLAG) + status_flags |= DM_STATUS_NOFLUSH_FLAG; + ti->type->status(ti, type, status_flags, outptr, remaining); + } else + outptr[0] = '\0'; + + l = strlen(outptr) + 1; + if (l == remaining) { + param->flags |= DM_BUFFER_FULL_FLAG; + break; + } + + outptr += l; + used = param->data_start + (outptr - outbuf); + + outptr = align_ptr(outptr); + spec->next = outptr - outbuf; + } + + if (used) + param->data_size = used; + + param->target_count = num_targets; +} + +/* + * Wait for a device to report an event + */ +static int dev_wait(struct file *filp, struct dm_ioctl *param, size_t param_size) +{ + int r = 0; + struct mapped_device *md; + struct dm_table *table; + int srcu_idx; + + md = find_device(param); + if (!md) + return -ENXIO; + + /* + * Wait for a notification event + */ + if (dm_wait_event(md, param->event_nr)) { + r = -ERESTARTSYS; + goto out; + } + + /* + * The userland program is going to want to know what + * changed to trigger the event, so we may as well tell + * him and save an ioctl. + */ + __dev_status(md, param); + + table = dm_get_live_or_inactive_table(md, param, &srcu_idx); + if (table) + retrieve_status(table, param, param_size); + dm_put_live_table(md, srcu_idx); + +out: + dm_put(md); + + return r; +} + +/* + * Remember the global event number and make it possible to poll + * for further events. + */ +static int dev_arm_poll(struct file *filp, struct dm_ioctl *param, size_t param_size) +{ + struct dm_file *priv = filp->private_data; + + priv->global_event_nr = atomic_read(&dm_global_event_nr); + + return 0; +} + +static inline blk_mode_t get_mode(struct dm_ioctl *param) +{ + blk_mode_t mode = BLK_OPEN_READ | BLK_OPEN_WRITE; + + if (param->flags & DM_READONLY_FLAG) + mode = BLK_OPEN_READ; + + return mode; +} + +static int next_target(struct dm_target_spec *last, uint32_t next, const char *end, + struct dm_target_spec **spec, char **target_params) +{ + static_assert(__alignof__(struct dm_target_spec) <= 8, + "struct dm_target_spec must not require more than 8-byte alignment"); + + /* + * Number of bytes remaining, starting with last. This is always + * sizeof(struct dm_target_spec) or more, as otherwise *last was + * out of bounds already. + */ + size_t remaining = end - (char *)last; + + /* + * There must be room for both the next target spec and the + * NUL-terminator of the target itself. + */ + if (remaining - sizeof(struct dm_target_spec) <= next) { + DMERR("Target spec extends beyond end of parameters"); + return -EINVAL; + } + + if (next % __alignof__(struct dm_target_spec)) { + DMERR("Next dm_target_spec (offset %u) is not %zu-byte aligned", + next, __alignof__(struct dm_target_spec)); + return -EINVAL; + } + + *spec = (struct dm_target_spec *) ((unsigned char *) last + next); + *target_params = (char *) (*spec + 1); + + return 0; +} + +static int populate_table(struct dm_table *table, + struct dm_ioctl *param, size_t param_size) +{ + int r; + unsigned int i = 0; + struct dm_target_spec *spec = (struct dm_target_spec *) param; + uint32_t next = param->data_start; + const char *const end = (const char *) param + param_size; + char *target_params; + size_t min_size = sizeof(struct dm_ioctl); + + if (!param->target_count) { + DMERR("%s: no targets specified", __func__); + return -EINVAL; + } + + for (i = 0; i < param->target_count; i++) { + const char *nul_terminator; + + if (next < min_size) { + DMERR("%s: next target spec (offset %u) overlaps %s", + __func__, next, i ? "previous target" : "'struct dm_ioctl'"); + return -EINVAL; + } + + r = next_target(spec, next, end, &spec, &target_params); + if (r) { + DMERR("unable to find target"); + return r; + } + + nul_terminator = memchr(target_params, 0, (size_t)(end - target_params)); + if (nul_terminator == NULL) { + DMERR("%s: target parameters not NUL-terminated", __func__); + return -EINVAL; + } + + /* Add 1 for NUL terminator */ + min_size = (size_t)(nul_terminator - (const char *)spec) + 1; + + r = dm_table_add_target(table, spec->target_type, + (sector_t) spec->sector_start, + (sector_t) spec->length, + target_params); + if (r) { + DMERR("error adding target to table"); + return r; + } + + next = spec->next; + } + + return dm_table_complete(table); +} + +static bool is_valid_type(enum dm_queue_mode cur, enum dm_queue_mode new) +{ + if (cur == new || + (cur == DM_TYPE_BIO_BASED && new == DM_TYPE_DAX_BIO_BASED)) + return true; + + return false; +} + +static int table_load(struct file *filp, struct dm_ioctl *param, size_t param_size) +{ + int r; + struct hash_cell *hc; + struct dm_table *t, *old_map = NULL; + struct mapped_device *md; + struct target_type *immutable_target_type; + + md = find_device(param); + if (!md) + return -ENXIO; + + r = dm_table_create(&t, get_mode(param), param->target_count, md); + if (r) + goto err; + + /* Protect md->type and md->queue against concurrent table loads. */ + dm_lock_md_type(md); + r = populate_table(t, param, param_size); + if (r) + goto err_unlock_md_type; + + dm_ima_measure_on_table_load(t, STATUSTYPE_IMA); + + immutable_target_type = dm_get_immutable_target_type(md); + if (immutable_target_type && + (immutable_target_type != dm_table_get_immutable_target_type(t)) && + !dm_table_get_wildcard_target(t)) { + DMERR("can't replace immutable target type %s", + immutable_target_type->name); + r = -EINVAL; + goto err_unlock_md_type; + } + + if (dm_get_md_type(md) == DM_TYPE_NONE) { + /* setup md->queue to reflect md's type (may block) */ + r = dm_setup_md_queue(md, t); + if (r) { + DMERR("unable to set up device queue for new table."); + goto err_unlock_md_type; + } + } else if (!is_valid_type(dm_get_md_type(md), dm_table_get_type(t))) { + DMERR("can't change device type (old=%u vs new=%u) after initial table load.", + dm_get_md_type(md), dm_table_get_type(t)); + r = -EINVAL; + goto err_unlock_md_type; + } + + dm_unlock_md_type(md); + + /* stage inactive table */ + down_write(&_hash_lock); + hc = dm_get_mdptr(md); + if (!hc) { + DMERR("device has been removed from the dev hash table."); + up_write(&_hash_lock); + r = -ENXIO; + goto err_destroy_table; + } + + if (hc->new_map) + old_map = hc->new_map; + hc->new_map = t; + up_write(&_hash_lock); + + param->flags |= DM_INACTIVE_PRESENT_FLAG; + __dev_status(md, param); + + if (old_map) { + dm_sync_table(md); + dm_table_destroy(old_map); + } + + dm_put(md); + + return 0; + +err_unlock_md_type: + dm_unlock_md_type(md); +err_destroy_table: + dm_table_destroy(t); +err: + dm_put(md); + + return r; +} + +static int table_clear(struct file *filp, struct dm_ioctl *param, size_t param_size) +{ + struct hash_cell *hc; + struct mapped_device *md; + struct dm_table *old_map = NULL; + bool has_new_map = false; + + down_write(&_hash_lock); + + hc = __find_device_hash_cell(param); + if (!hc) { + DMDEBUG_LIMIT("device doesn't appear to be in the dev hash table."); + up_write(&_hash_lock); + return -ENXIO; + } + + if (hc->new_map) { + old_map = hc->new_map; + hc->new_map = NULL; + has_new_map = true; + } + + md = hc->md; + up_write(&_hash_lock); + + param->flags &= ~DM_INACTIVE_PRESENT_FLAG; + __dev_status(md, param); + + if (old_map) { + dm_sync_table(md); + dm_table_destroy(old_map); + } + dm_ima_measure_on_table_clear(md, has_new_map); + dm_put(md); + + return 0; +} + +/* + * Retrieves a list of devices used by a particular dm device. + */ +static void retrieve_deps(struct dm_table *table, + struct dm_ioctl *param, size_t param_size) +{ + unsigned int count = 0; + struct list_head *tmp; + size_t len, needed; + struct dm_dev_internal *dd; + struct dm_target_deps *deps; + + down_read(&table->devices_lock); + + deps = get_result_buffer(param, param_size, &len); + + /* + * Count the devices. + */ + list_for_each(tmp, dm_table_get_devices(table)) + count++; + + /* + * Check we have enough space. + */ + needed = struct_size(deps, dev, count); + if (len < needed) { + param->flags |= DM_BUFFER_FULL_FLAG; + goto out; + } + + /* + * Fill in the devices. + */ + deps->count = count; + count = 0; + list_for_each_entry(dd, dm_table_get_devices(table), list) + deps->dev[count++] = huge_encode_dev(dd->dm_dev->bdev->bd_dev); + + param->data_size = param->data_start + needed; + +out: + up_read(&table->devices_lock); +} + +static int table_deps(struct file *filp, struct dm_ioctl *param, size_t param_size) +{ + struct mapped_device *md; + struct dm_table *table; + int srcu_idx; + + md = find_device(param); + if (!md) + return -ENXIO; + + __dev_status(md, param); + + table = dm_get_live_or_inactive_table(md, param, &srcu_idx); + if (table) + retrieve_deps(table, param, param_size); + dm_put_live_table(md, srcu_idx); + + dm_put(md); + + return 0; +} + +/* + * Return the status of a device as a text string for each + * target. + */ +static int table_status(struct file *filp, struct dm_ioctl *param, size_t param_size) +{ + struct mapped_device *md; + struct dm_table *table; + int srcu_idx; + + md = find_device(param); + if (!md) + return -ENXIO; + + __dev_status(md, param); + + table = dm_get_live_or_inactive_table(md, param, &srcu_idx); + if (table) + retrieve_status(table, param, param_size); + dm_put_live_table(md, srcu_idx); + + dm_put(md); + + return 0; +} + +/* + * Process device-mapper dependent messages. Messages prefixed with '@' + * are processed by the DM core. All others are delivered to the target. + * Returns a number <= 1 if message was processed by device mapper. + * Returns 2 if message should be delivered to the target. + */ +static int message_for_md(struct mapped_device *md, unsigned int argc, char **argv, + char *result, unsigned int maxlen) +{ + int r; + + if (**argv != '@') + return 2; /* no '@' prefix, deliver to target */ + + if (!strcasecmp(argv[0], "@cancel_deferred_remove")) { + if (argc != 1) { + DMERR("Invalid arguments for @cancel_deferred_remove"); + return -EINVAL; + } + return dm_cancel_deferred_remove(md); + } + + r = dm_stats_message(md, argc, argv, result, maxlen); + if (r < 2) + return r; + + DMERR("Unsupported message sent to DM core: %s", argv[0]); + return -EINVAL; +} + +/* + * Pass a message to the target that's at the supplied device offset. + */ +static int target_message(struct file *filp, struct dm_ioctl *param, size_t param_size) +{ + int r, argc; + char **argv; + struct mapped_device *md; + struct dm_table *table; + struct dm_target *ti; + struct dm_target_msg *tmsg = (void *) param + param->data_start; + size_t maxlen; + char *result = get_result_buffer(param, param_size, &maxlen); + int srcu_idx; + + md = find_device(param); + if (!md) + return -ENXIO; + + if (tmsg < (struct dm_target_msg *) param->data || + invalid_str(tmsg->message, (void *) param + param_size)) { + DMERR("Invalid target message parameters."); + r = -EINVAL; + goto out; + } + + r = dm_split_args(&argc, &argv, tmsg->message); + if (r) { + DMERR("Failed to split target message parameters"); + goto out; + } + + if (!argc) { + DMERR("Empty message received."); + r = -EINVAL; + goto out_argv; + } + + r = message_for_md(md, argc, argv, result, maxlen); + if (r <= 1) + goto out_argv; + + table = dm_get_live_table(md, &srcu_idx); + if (!table) + goto out_table; + + if (dm_deleting_md(md)) { + r = -ENXIO; + goto out_table; + } + + ti = dm_table_find_target(table, tmsg->sector); + if (!ti) { + DMERR("Target message sector outside device."); + r = -EINVAL; + } else if (ti->type->message) + r = ti->type->message(ti, argc, argv, result, maxlen); + else { + DMERR("Target type does not support messages"); + r = -EINVAL; + } + + out_table: + dm_put_live_table(md, srcu_idx); + out_argv: + kfree(argv); + out: + if (r >= 0) + __dev_status(md, param); + + if (r == 1) { + param->flags |= DM_DATA_OUT_FLAG; + if (dm_message_test_buffer_overflow(result, maxlen)) + param->flags |= DM_BUFFER_FULL_FLAG; + else + param->data_size = param->data_start + strlen(result) + 1; + r = 0; + } + + dm_put(md); + return r; +} + +/* + * The ioctl parameter block consists of two parts, a dm_ioctl struct + * followed by a data buffer. This flag is set if the second part, + * which has a variable size, is not used by the function processing + * the ioctl. + */ +#define IOCTL_FLAGS_NO_PARAMS 1 +#define IOCTL_FLAGS_ISSUE_GLOBAL_EVENT 2 + +/* + *--------------------------------------------------------------- + * Implementation of open/close/ioctl on the special char device. + *--------------------------------------------------------------- + */ +static ioctl_fn lookup_ioctl(unsigned int cmd, int *ioctl_flags) +{ + static const struct { + int cmd; + int flags; + ioctl_fn fn; + } _ioctls[] = { + {DM_VERSION_CMD, 0, NULL}, /* version is dealt with elsewhere */ + {DM_REMOVE_ALL_CMD, IOCTL_FLAGS_NO_PARAMS | IOCTL_FLAGS_ISSUE_GLOBAL_EVENT, remove_all}, + {DM_LIST_DEVICES_CMD, 0, list_devices}, + + {DM_DEV_CREATE_CMD, IOCTL_FLAGS_NO_PARAMS | IOCTL_FLAGS_ISSUE_GLOBAL_EVENT, dev_create}, + {DM_DEV_REMOVE_CMD, IOCTL_FLAGS_NO_PARAMS | IOCTL_FLAGS_ISSUE_GLOBAL_EVENT, dev_remove}, + {DM_DEV_RENAME_CMD, IOCTL_FLAGS_ISSUE_GLOBAL_EVENT, dev_rename}, + {DM_DEV_SUSPEND_CMD, IOCTL_FLAGS_NO_PARAMS, dev_suspend}, + {DM_DEV_STATUS_CMD, IOCTL_FLAGS_NO_PARAMS, dev_status}, + {DM_DEV_WAIT_CMD, 0, dev_wait}, + + {DM_TABLE_LOAD_CMD, 0, table_load}, + {DM_TABLE_CLEAR_CMD, IOCTL_FLAGS_NO_PARAMS, table_clear}, + {DM_TABLE_DEPS_CMD, 0, table_deps}, + {DM_TABLE_STATUS_CMD, 0, table_status}, + + {DM_LIST_VERSIONS_CMD, 0, list_versions}, + + {DM_TARGET_MSG_CMD, 0, target_message}, + {DM_DEV_SET_GEOMETRY_CMD, 0, dev_set_geometry}, + {DM_DEV_ARM_POLL_CMD, IOCTL_FLAGS_NO_PARAMS, dev_arm_poll}, + {DM_GET_TARGET_VERSION_CMD, 0, get_target_version}, + }; + + if (unlikely(cmd >= ARRAY_SIZE(_ioctls))) + return NULL; + + cmd = array_index_nospec(cmd, ARRAY_SIZE(_ioctls)); + *ioctl_flags = _ioctls[cmd].flags; + return _ioctls[cmd].fn; +} + +/* + * As well as checking the version compatibility this always + * copies the kernel interface version out. + */ +static int check_version(unsigned int cmd, struct dm_ioctl __user *user, + struct dm_ioctl *kernel_params) +{ + int r = 0; + + /* Make certain version is first member of dm_ioctl struct */ + BUILD_BUG_ON(offsetof(struct dm_ioctl, version) != 0); + + if (copy_from_user(kernel_params->version, user->version, sizeof(kernel_params->version))) + return -EFAULT; + + if ((kernel_params->version[0] != DM_VERSION_MAJOR) || + (kernel_params->version[1] > DM_VERSION_MINOR)) { + DMERR("ioctl interface mismatch: kernel(%u.%u.%u), user(%u.%u.%u), cmd(%d)", + DM_VERSION_MAJOR, DM_VERSION_MINOR, + DM_VERSION_PATCHLEVEL, + kernel_params->version[0], + kernel_params->version[1], + kernel_params->version[2], + cmd); + r = -EINVAL; + } + + /* + * Fill in the kernel version. + */ + kernel_params->version[0] = DM_VERSION_MAJOR; + kernel_params->version[1] = DM_VERSION_MINOR; + kernel_params->version[2] = DM_VERSION_PATCHLEVEL; + if (copy_to_user(user->version, kernel_params->version, sizeof(kernel_params->version))) + return -EFAULT; + + return r; +} + +#define DM_PARAMS_MALLOC 0x0001 /* Params allocated with kvmalloc() */ +#define DM_WIPE_BUFFER 0x0010 /* Wipe input buffer before returning from ioctl */ + +static void free_params(struct dm_ioctl *param, size_t param_size, int param_flags) +{ + if (param_flags & DM_WIPE_BUFFER) + memset(param, 0, param_size); + + if (param_flags & DM_PARAMS_MALLOC) + kvfree(param); +} + +static int copy_params(struct dm_ioctl __user *user, struct dm_ioctl *param_kernel, + int ioctl_flags, struct dm_ioctl **param, int *param_flags) +{ + struct dm_ioctl *dmi; + int secure_data; + const size_t minimum_data_size = offsetof(struct dm_ioctl, data); + + /* check_version() already copied version from userspace, avoid TOCTOU */ + if (copy_from_user((char *)param_kernel + sizeof(param_kernel->version), + (char __user *)user + sizeof(param_kernel->version), + minimum_data_size - sizeof(param_kernel->version))) + return -EFAULT; + + if (param_kernel->data_size < minimum_data_size) { + DMERR("Invalid data size in the ioctl structure: %u", + param_kernel->data_size); + return -EINVAL; + } + + secure_data = param_kernel->flags & DM_SECURE_DATA_FLAG; + + *param_flags = secure_data ? DM_WIPE_BUFFER : 0; + + if (ioctl_flags & IOCTL_FLAGS_NO_PARAMS) { + dmi = param_kernel; + dmi->data_size = minimum_data_size; + goto data_copied; + } + + /* + * Use __GFP_HIGH to avoid low memory issues when a device is + * suspended and the ioctl is needed to resume it. + * Use kmalloc() rather than vmalloc() when we can. + */ + dmi = NULL; + dmi = kvmalloc(param_kernel->data_size, GFP_NOIO | __GFP_HIGH); + + if (!dmi) { + if (secure_data && clear_user(user, param_kernel->data_size)) + return -EFAULT; + return -ENOMEM; + } + + *param_flags |= DM_PARAMS_MALLOC; + + /* Copy from param_kernel (which was already copied from user) */ + memcpy(dmi, param_kernel, minimum_data_size); + + if (copy_from_user(&dmi->data, (char __user *)user + minimum_data_size, + param_kernel->data_size - minimum_data_size)) + goto bad; +data_copied: + /* Wipe the user buffer so we do not return it to userspace */ + if (secure_data && clear_user(user, param_kernel->data_size)) + goto bad; + + *param = dmi; + return 0; + +bad: + free_params(dmi, param_kernel->data_size, *param_flags); + + return -EFAULT; +} + +static int validate_params(uint cmd, struct dm_ioctl *param) +{ + /* Always clear this flag */ + param->flags &= ~DM_BUFFER_FULL_FLAG; + param->flags &= ~DM_UEVENT_GENERATED_FLAG; + param->flags &= ~DM_SECURE_DATA_FLAG; + param->flags &= ~DM_DATA_OUT_FLAG; + + /* Ignores parameters */ + if (cmd == DM_REMOVE_ALL_CMD || + cmd == DM_LIST_DEVICES_CMD || + cmd == DM_LIST_VERSIONS_CMD) + return 0; + + if (cmd == DM_DEV_CREATE_CMD) { + if (!*param->name) { + DMERR("name not supplied when creating device"); + return -EINVAL; + } + } else if (*param->uuid && *param->name) { + DMERR("only supply one of name or uuid, cmd(%u)", cmd); + return -EINVAL; + } + + /* Ensure strings are terminated */ + param->name[DM_NAME_LEN - 1] = '\0'; + param->uuid[DM_UUID_LEN - 1] = '\0'; + + return 0; +} + +static int ctl_ioctl(struct file *file, uint command, struct dm_ioctl __user *user) +{ + int r = 0; + int ioctl_flags; + int param_flags; + unsigned int cmd; + struct dm_ioctl *param; + ioctl_fn fn = NULL; + size_t input_param_size; + struct dm_ioctl param_kernel; + + /* only root can play with this */ + if (!capable(CAP_SYS_ADMIN)) + return -EACCES; + + if (_IOC_TYPE(command) != DM_IOCTL) + return -ENOTTY; + + cmd = _IOC_NR(command); + + /* + * Check the interface version passed in. This also + * writes out the kernel's interface version. + */ + r = check_version(cmd, user, ¶m_kernel); + if (r) + return r; + + /* + * Nothing more to do for the version command. + */ + if (cmd == DM_VERSION_CMD) + return 0; + + fn = lookup_ioctl(cmd, &ioctl_flags); + if (!fn) { + DMERR("dm_ctl_ioctl: unknown command 0x%x", command); + return -ENOTTY; + } + + /* + * Copy the parameters into kernel space. + */ + r = copy_params(user, ¶m_kernel, ioctl_flags, ¶m, ¶m_flags); + + if (r) + return r; + + input_param_size = param->data_size; + r = validate_params(cmd, param); + if (r) + goto out; + + param->data_size = offsetof(struct dm_ioctl, data); + r = fn(file, param, input_param_size); + + if (unlikely(param->flags & DM_BUFFER_FULL_FLAG) && + unlikely(ioctl_flags & IOCTL_FLAGS_NO_PARAMS)) + DMERR("ioctl %d tried to output some data but has IOCTL_FLAGS_NO_PARAMS set", cmd); + + if (!r && ioctl_flags & IOCTL_FLAGS_ISSUE_GLOBAL_EVENT) + dm_issue_global_event(); + + /* + * Copy the results back to userland. + */ + if (!r && copy_to_user(user, param, param->data_size)) + r = -EFAULT; + +out: + free_params(param, input_param_size, param_flags); + return r; +} + +static long dm_ctl_ioctl(struct file *file, uint command, ulong u) +{ + return (long)ctl_ioctl(file, command, (struct dm_ioctl __user *)u); +} + +#ifdef CONFIG_COMPAT +static long dm_compat_ctl_ioctl(struct file *file, uint command, ulong u) +{ + return (long)dm_ctl_ioctl(file, command, (ulong) compat_ptr(u)); +} +#else +#define dm_compat_ctl_ioctl NULL +#endif + +static int dm_open(struct inode *inode, struct file *filp) +{ + int r; + struct dm_file *priv; + + r = nonseekable_open(inode, filp); + if (unlikely(r)) + return r; + + priv = filp->private_data = kmalloc(sizeof(struct dm_file), GFP_KERNEL); + if (!priv) + return -ENOMEM; + + priv->global_event_nr = atomic_read(&dm_global_event_nr); + + return 0; +} + +static int dm_release(struct inode *inode, struct file *filp) +{ + kfree(filp->private_data); + return 0; +} + +static __poll_t dm_poll(struct file *filp, poll_table *wait) +{ + struct dm_file *priv = filp->private_data; + __poll_t mask = 0; + + poll_wait(filp, &dm_global_eventq, wait); + + if ((int)(atomic_read(&dm_global_event_nr) - priv->global_event_nr) > 0) + mask |= EPOLLIN; + + return mask; +} + +static const struct file_operations _ctl_fops = { + .open = dm_open, + .release = dm_release, + .poll = dm_poll, + .unlocked_ioctl = dm_ctl_ioctl, + .compat_ioctl = dm_compat_ctl_ioctl, + .owner = THIS_MODULE, + .llseek = noop_llseek, +}; + +static struct miscdevice _dm_misc = { + .minor = MAPPER_CTRL_MINOR, + .name = DM_NAME, + .nodename = DM_DIR "/" DM_CONTROL_NODE, + .fops = &_ctl_fops +}; + +MODULE_ALIAS_MISCDEV(MAPPER_CTRL_MINOR); +MODULE_ALIAS("devname:" DM_DIR "/" DM_CONTROL_NODE); + +/* + * Create misc character device and link to DM_DIR/control. + */ +int __init dm_interface_init(void) +{ + int r; + + r = misc_register(&_dm_misc); + if (r) { + DMERR("misc_register failed for control device"); + return r; + } + + DMINFO("%d.%d.%d%s initialised: %s", DM_VERSION_MAJOR, + DM_VERSION_MINOR, DM_VERSION_PATCHLEVEL, DM_VERSION_EXTRA, + DM_DRIVER_EMAIL); + return 0; +} + +void dm_interface_exit(void) +{ + misc_deregister(&_dm_misc); + dm_hash_exit(); +} + +/** + * dm_copy_name_and_uuid - Copy mapped device name & uuid into supplied buffers + * @md: Pointer to mapped_device + * @name: Buffer (size DM_NAME_LEN) for name + * @uuid: Buffer (size DM_UUID_LEN) for uuid or empty string if uuid not defined + */ +int dm_copy_name_and_uuid(struct mapped_device *md, char *name, char *uuid) +{ + int r = 0; + struct hash_cell *hc; + + if (!md) + return -ENXIO; + + mutex_lock(&dm_hash_cells_mutex); + hc = dm_get_mdptr(md); + if (!hc) { + r = -ENXIO; + goto out; + } + + if (name) + strcpy(name, hc->name); + if (uuid) + strcpy(uuid, hc->uuid ? : ""); + +out: + mutex_unlock(&dm_hash_cells_mutex); + + return r; +} +EXPORT_SYMBOL_GPL(dm_copy_name_and_uuid); + +/** + * dm_early_create - create a mapped device in early boot. + * + * @dmi: Contains main information of the device mapping to be created. + * @spec_array: array of pointers to struct dm_target_spec. Describes the + * mapping table of the device. + * @target_params_array: array of strings with the parameters to a specific + * target. + * + * Instead of having the struct dm_target_spec and the parameters for every + * target embedded at the end of struct dm_ioctl (as performed in a normal + * ioctl), pass them as arguments, so the caller doesn't need to serialize them. + * The size of the spec_array and target_params_array is given by + * @dmi->target_count. + * This function is supposed to be called in early boot, so locking mechanisms + * to protect against concurrent loads are not required. + */ +int __init dm_early_create(struct dm_ioctl *dmi, + struct dm_target_spec **spec_array, + char **target_params_array) +{ + int r, m = DM_ANY_MINOR; + struct dm_table *t, *old_map; + struct mapped_device *md; + unsigned int i; + + if (!dmi->target_count) + return -EINVAL; + + r = check_name(dmi->name); + if (r) + return r; + + if (dmi->flags & DM_PERSISTENT_DEV_FLAG) + m = MINOR(huge_decode_dev(dmi->dev)); + + /* alloc dm device */ + r = dm_create(m, &md); + if (r) + return r; + + /* hash insert */ + r = dm_hash_insert(dmi->name, *dmi->uuid ? dmi->uuid : NULL, md); + if (r) + goto err_destroy_dm; + + /* alloc table */ + r = dm_table_create(&t, get_mode(dmi), dmi->target_count, md); + if (r) + goto err_hash_remove; + + /* add targets */ + for (i = 0; i < dmi->target_count; i++) { + r = dm_table_add_target(t, spec_array[i]->target_type, + (sector_t) spec_array[i]->sector_start, + (sector_t) spec_array[i]->length, + target_params_array[i]); + if (r) { + DMERR("error adding target to table"); + goto err_destroy_table; + } + } + + /* finish table */ + r = dm_table_complete(t); + if (r) + goto err_destroy_table; + + /* setup md->queue to reflect md's type (may block) */ + r = dm_setup_md_queue(md, t); + if (r) { + DMERR("unable to set up device queue for new table."); + goto err_destroy_table; + } + + /* Set new map */ + dm_suspend(md, 0); + old_map = dm_swap_table(md, t); + if (IS_ERR(old_map)) { + r = PTR_ERR(old_map); + goto err_destroy_table; + } + set_disk_ro(dm_disk(md), !!(dmi->flags & DM_READONLY_FLAG)); + + /* resume device */ + r = dm_resume(md); + if (r) + goto err_destroy_table; + + DMINFO("%s (%s) is ready", md->disk->disk_name, dmi->name); + dm_put(md); + return 0; + +err_destroy_table: + dm_table_destroy(t); +err_hash_remove: + down_write(&_hash_lock); + (void) __hash_remove(__get_name_cell(dmi->name)); + up_write(&_hash_lock); + /* release reference from __get_name_cell */ + dm_put(md); +err_destroy_dm: + dm_put(md); + dm_destroy(md); + return r; +} |