306 lines
9.3 KiB
C
306 lines
9.3 KiB
C
/*
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* security/tomoyo/mount.c
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*
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* Copyright (C) 2005-2010 NTT DATA CORPORATION
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*/
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#include <linux/slab.h>
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#include "common.h"
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/* Keywords for mount restrictions. */
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/* Allow to call 'mount --bind /source_dir /dest_dir' */
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#define TOMOYO_MOUNT_BIND_KEYWORD "--bind"
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/* Allow to call 'mount --move /old_dir /new_dir ' */
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#define TOMOYO_MOUNT_MOVE_KEYWORD "--move"
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/* Allow to call 'mount -o remount /dir ' */
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#define TOMOYO_MOUNT_REMOUNT_KEYWORD "--remount"
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/* Allow to call 'mount --make-unbindable /dir' */
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#define TOMOYO_MOUNT_MAKE_UNBINDABLE_KEYWORD "--make-unbindable"
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/* Allow to call 'mount --make-private /dir' */
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#define TOMOYO_MOUNT_MAKE_PRIVATE_KEYWORD "--make-private"
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/* Allow to call 'mount --make-slave /dir' */
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#define TOMOYO_MOUNT_MAKE_SLAVE_KEYWORD "--make-slave"
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/* Allow to call 'mount --make-shared /dir' */
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#define TOMOYO_MOUNT_MAKE_SHARED_KEYWORD "--make-shared"
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/**
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* tomoyo_mount_acl2 - Check permission for mount() operation.
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*
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* @r: Pointer to "struct tomoyo_request_info".
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* @dev_name: Name of device file.
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* @dir: Pointer to "struct path".
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* @type: Name of filesystem type.
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* @flags: Mount options.
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*
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* Returns 0 on success, negative value otherwise.
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*
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* Caller holds tomoyo_read_lock().
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*/
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static int tomoyo_mount_acl2(struct tomoyo_request_info *r, char *dev_name,
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struct path *dir, char *type, unsigned long flags)
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{
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struct path path;
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struct tomoyo_acl_info *ptr;
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struct file_system_type *fstype = NULL;
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const char *requested_type = NULL;
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const char *requested_dir_name = NULL;
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const char *requested_dev_name = NULL;
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struct tomoyo_path_info rtype;
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struct tomoyo_path_info rdev;
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struct tomoyo_path_info rdir;
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int need_dev = 0;
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int error = -ENOMEM;
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/* Get fstype. */
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requested_type = tomoyo_encode(type);
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if (!requested_type)
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goto out;
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rtype.name = requested_type;
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tomoyo_fill_path_info(&rtype);
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/* Get mount point. */
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requested_dir_name = tomoyo_realpath_from_path(dir);
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if (!requested_dir_name) {
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error = -ENOMEM;
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goto out;
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}
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rdir.name = requested_dir_name;
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tomoyo_fill_path_info(&rdir);
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/* Compare fs name. */
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if (!strcmp(type, TOMOYO_MOUNT_REMOUNT_KEYWORD)) {
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/* dev_name is ignored. */
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} else if (!strcmp(type, TOMOYO_MOUNT_MAKE_UNBINDABLE_KEYWORD) ||
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!strcmp(type, TOMOYO_MOUNT_MAKE_PRIVATE_KEYWORD) ||
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!strcmp(type, TOMOYO_MOUNT_MAKE_SLAVE_KEYWORD) ||
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!strcmp(type, TOMOYO_MOUNT_MAKE_SHARED_KEYWORD)) {
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/* dev_name is ignored. */
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} else if (!strcmp(type, TOMOYO_MOUNT_BIND_KEYWORD) ||
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!strcmp(type, TOMOYO_MOUNT_MOVE_KEYWORD)) {
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need_dev = -1; /* dev_name is a directory */
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} else {
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fstype = get_fs_type(type);
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if (!fstype) {
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error = -ENODEV;
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goto out;
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}
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if (fstype->fs_flags & FS_REQUIRES_DEV)
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/* dev_name is a block device file. */
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need_dev = 1;
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}
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if (need_dev) {
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/* Get mount point or device file. */
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if (kern_path(dev_name, LOOKUP_FOLLOW, &path)) {
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error = -ENOENT;
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goto out;
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}
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requested_dev_name = tomoyo_realpath_from_path(&path);
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if (!requested_dev_name) {
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error = -ENOENT;
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goto out;
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}
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} else {
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/* Map dev_name to "<NULL>" if no dev_name given. */
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if (!dev_name)
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dev_name = "<NULL>";
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requested_dev_name = tomoyo_encode(dev_name);
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if (!requested_dev_name) {
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error = -ENOMEM;
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goto out;
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}
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}
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rdev.name = requested_dev_name;
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tomoyo_fill_path_info(&rdev);
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list_for_each_entry_rcu(ptr, &r->domain->acl_info_list, list) {
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struct tomoyo_mount_acl *acl;
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if (ptr->is_deleted || ptr->type != TOMOYO_TYPE_MOUNT_ACL)
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continue;
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acl = container_of(ptr, struct tomoyo_mount_acl, head);
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if (!tomoyo_compare_number_union(flags, &acl->flags) ||
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!tomoyo_compare_name_union(&rtype, &acl->fs_type) ||
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!tomoyo_compare_name_union(&rdir, &acl->dir_name) ||
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(need_dev &&
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!tomoyo_compare_name_union(&rdev, &acl->dev_name)))
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continue;
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error = 0;
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break;
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}
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if (error)
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error = tomoyo_supervisor(r, TOMOYO_KEYWORD_ALLOW_MOUNT
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"%s %s %s 0x%lX\n",
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tomoyo_file_pattern(&rdev),
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tomoyo_file_pattern(&rdir),
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requested_type, flags);
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out:
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kfree(requested_dev_name);
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kfree(requested_dir_name);
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if (fstype)
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put_filesystem(fstype);
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kfree(requested_type);
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return error;
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}
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/**
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* tomoyo_mount_acl - Check permission for mount() operation.
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*
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* @r: Pointer to "struct tomoyo_request_info".
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* @dev_name: Name of device file.
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* @dir: Pointer to "struct path".
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* @type: Name of filesystem type.
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* @flags: Mount options.
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*
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* Returns 0 on success, negative value otherwise.
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*
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* Caller holds tomoyo_read_lock().
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*/
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static int tomoyo_mount_acl(struct tomoyo_request_info *r, char *dev_name,
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struct path *dir, char *type, unsigned long flags)
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{
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int error;
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error = -EPERM;
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if ((flags & MS_MGC_MSK) == MS_MGC_VAL)
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flags &= ~MS_MGC_MSK;
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switch (flags & (MS_REMOUNT | MS_MOVE | MS_BIND)) {
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case MS_REMOUNT:
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case MS_MOVE:
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case MS_BIND:
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case 0:
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break;
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default:
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printk(KERN_WARNING "ERROR: "
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"%s%s%sare given for single mount operation.\n",
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flags & MS_REMOUNT ? "'remount' " : "",
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flags & MS_MOVE ? "'move' " : "",
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flags & MS_BIND ? "'bind' " : "");
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return -EINVAL;
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}
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switch (flags & (MS_UNBINDABLE | MS_PRIVATE | MS_SLAVE | MS_SHARED)) {
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case MS_UNBINDABLE:
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case MS_PRIVATE:
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case MS_SLAVE:
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case MS_SHARED:
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case 0:
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break;
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default:
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printk(KERN_WARNING "ERROR: "
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"%s%s%s%sare given for single mount operation.\n",
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flags & MS_UNBINDABLE ? "'unbindable' " : "",
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flags & MS_PRIVATE ? "'private' " : "",
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flags & MS_SLAVE ? "'slave' " : "",
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flags & MS_SHARED ? "'shared' " : "");
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return -EINVAL;
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}
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if (flags & MS_REMOUNT)
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error = tomoyo_mount_acl(r, dev_name, dir,
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TOMOYO_MOUNT_REMOUNT_KEYWORD,
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flags & ~MS_REMOUNT);
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else if (flags & MS_MOVE)
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error = tomoyo_mount_acl(r, dev_name, dir,
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TOMOYO_MOUNT_MOVE_KEYWORD,
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flags & ~MS_MOVE);
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else if (flags & MS_BIND)
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error = tomoyo_mount_acl(r, dev_name, dir,
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TOMOYO_MOUNT_BIND_KEYWORD,
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flags & ~MS_BIND);
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else if (flags & MS_UNBINDABLE)
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error = tomoyo_mount_acl(r, dev_name, dir,
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TOMOYO_MOUNT_MAKE_UNBINDABLE_KEYWORD,
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flags & ~MS_UNBINDABLE);
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else if (flags & MS_PRIVATE)
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error = tomoyo_mount_acl(r, dev_name, dir,
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TOMOYO_MOUNT_MAKE_PRIVATE_KEYWORD,
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flags & ~MS_PRIVATE);
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else if (flags & MS_SLAVE)
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error = tomoyo_mount_acl(r, dev_name, dir,
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TOMOYO_MOUNT_MAKE_SLAVE_KEYWORD,
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flags & ~MS_SLAVE);
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else if (flags & MS_SHARED)
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error = tomoyo_mount_acl(r, dev_name, dir,
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TOMOYO_MOUNT_MAKE_SHARED_KEYWORD,
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flags & ~MS_SHARED);
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else
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do {
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error = tomoyo_mount_acl2(r, dev_name, dir, type,
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flags);
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} while (error == TOMOYO_RETRY_REQUEST);
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if (r->mode != TOMOYO_CONFIG_ENFORCING)
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error = 0;
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return error;
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}
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/**
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* tomoyo_mount_permission - Check permission for mount() operation.
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*
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* @dev_name: Name of device file.
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* @path: Pointer to "struct path".
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* @type: Name of filesystem type. May be NULL.
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* @flags: Mount options.
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* @data_page: Optional data. May be NULL.
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*
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* Returns 0 on success, negative value otherwise.
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*/
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int tomoyo_mount_permission(char *dev_name, struct path *path, char *type,
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unsigned long flags, void *data_page)
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{
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struct tomoyo_request_info r;
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int error;
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int idx;
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if (tomoyo_init_request_info(&r, NULL, TOMOYO_MAC_FILE_MOUNT)
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== TOMOYO_CONFIG_DISABLED)
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return 0;
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if (!type)
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type = "<NULL>";
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idx = tomoyo_read_lock();
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error = tomoyo_mount_acl(&r, dev_name, path, type, flags);
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tomoyo_read_unlock(idx);
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return error;
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}
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static bool tomoyo_same_mount_acl(const struct tomoyo_acl_info *a,
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const struct tomoyo_acl_info *b)
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{
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const struct tomoyo_mount_acl *p1 = container_of(a, typeof(*p1), head);
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const struct tomoyo_mount_acl *p2 = container_of(b, typeof(*p2), head);
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return tomoyo_is_same_acl_head(&p1->head, &p2->head) &&
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tomoyo_is_same_name_union(&p1->dev_name, &p2->dev_name) &&
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tomoyo_is_same_name_union(&p1->dir_name, &p2->dir_name) &&
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tomoyo_is_same_name_union(&p1->fs_type, &p2->fs_type) &&
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tomoyo_is_same_number_union(&p1->flags, &p2->flags);
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}
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/**
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* tomoyo_write_mount_policy - Write "struct tomoyo_mount_acl" list.
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*
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* @data: String to parse.
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* @domain: Pointer to "struct tomoyo_domain_info".
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* @is_delete: True if it is a delete request.
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*
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* Returns 0 on success, negative value otherwise.
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*
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* Caller holds tomoyo_read_lock().
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*/
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int tomoyo_write_mount_policy(char *data, struct tomoyo_domain_info *domain,
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const bool is_delete)
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{
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struct tomoyo_mount_acl e = { .head.type = TOMOYO_TYPE_MOUNT_ACL };
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int error = is_delete ? -ENOENT : -ENOMEM;
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char *w[4];
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if (!tomoyo_tokenize(data, w, sizeof(w)) || !w[3][0])
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return -EINVAL;
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if (!tomoyo_parse_name_union(w[0], &e.dev_name) ||
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!tomoyo_parse_name_union(w[1], &e.dir_name) ||
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!tomoyo_parse_name_union(w[2], &e.fs_type) ||
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!tomoyo_parse_number_union(w[3], &e.flags))
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goto out;
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error = tomoyo_update_domain(&e.head, sizeof(e), is_delete, domain,
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tomoyo_same_mount_acl, NULL);
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out:
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tomoyo_put_name_union(&e.dev_name);
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tomoyo_put_name_union(&e.dir_name);
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tomoyo_put_name_union(&e.fs_type);
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tomoyo_put_number_union(&e.flags);
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return error;
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}
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