285 lines
8.7 KiB
C
285 lines
8.7 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_audit_mount_log - Audit mount log.
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*
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* @r: Pointer to "struct tomoyo_request_info".
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*
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* Returns 0 on success, negative value otherwise.
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*/
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static int tomoyo_audit_mount_log(struct tomoyo_request_info *r)
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{
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const char *dev = r->param.mount.dev->name;
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const char *dir = r->param.mount.dir->name;
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const char *type = r->param.mount.type->name;
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const unsigned long flags = r->param.mount.flags;
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if (r->granted)
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return 0;
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if (!strcmp(type, TOMOYO_MOUNT_REMOUNT_KEYWORD))
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tomoyo_warn_log(r, "mount -o remount %s 0x%lX", dir, flags);
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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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tomoyo_warn_log(r, "mount %s %s %s 0x%lX", type, dev, dir,
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flags);
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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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tomoyo_warn_log(r, "mount %s %s 0x%lX", type, dir, flags);
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else
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tomoyo_warn_log(r, "mount -t %s %s %s 0x%lX", type, dev, dir,
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flags);
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return tomoyo_supervisor(r,
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TOMOYO_KEYWORD_ALLOW_MOUNT "%s %s %s 0x%lX\n",
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tomoyo_pattern(r->param.mount.dev),
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tomoyo_pattern(r->param.mount.dir), type,
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flags);
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}
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static bool tomoyo_check_mount_acl(struct tomoyo_request_info *r,
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const struct tomoyo_acl_info *ptr)
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{
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const struct tomoyo_mount_acl *acl =
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container_of(ptr, typeof(*acl), head);
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return tomoyo_compare_number_union(r->param.mount.flags, &acl->flags) &&
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tomoyo_compare_name_union(r->param.mount.type, &acl->fs_type) &&
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tomoyo_compare_name_union(r->param.mount.dir, &acl->dir_name) &&
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(!r->param.mount.need_dev ||
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tomoyo_compare_name_union(r->param.mount.dev, &acl->dev_name));
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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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struct path path;
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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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r->param_type = TOMOYO_TYPE_MOUNT_ACL;
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r->param.mount.need_dev = need_dev;
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r->param.mount.dev = &rdev;
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r->param.mount.dir = &rdir;
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r->param.mount.type = &rtype;
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r->param.mount.flags = flags;
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do {
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tomoyo_check_acl(r, tomoyo_check_mount_acl);
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error = tomoyo_audit_mount_log(r);
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} while (error == TOMOYO_RETRY_REQUEST);
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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_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 ((flags & MS_MGC_MSK) == MS_MGC_VAL)
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flags &= ~MS_MGC_MSK;
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if (flags & MS_REMOUNT) {
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type = TOMOYO_MOUNT_REMOUNT_KEYWORD;
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flags &= ~MS_REMOUNT;
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}
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if (flags & MS_MOVE) {
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type = TOMOYO_MOUNT_MOVE_KEYWORD;
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flags &= ~MS_MOVE;
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}
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if (flags & MS_BIND) {
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type = TOMOYO_MOUNT_BIND_KEYWORD;
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flags &= ~MS_BIND;
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}
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if (flags & MS_UNBINDABLE) {
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type = TOMOYO_MOUNT_MAKE_UNBINDABLE_KEYWORD;
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flags &= ~MS_UNBINDABLE;
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}
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if (flags & MS_PRIVATE) {
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type = TOMOYO_MOUNT_MAKE_PRIVATE_KEYWORD;
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flags &= ~MS_PRIVATE;
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}
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if (flags & MS_SLAVE) {
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type = TOMOYO_MOUNT_MAKE_SLAVE_KEYWORD;
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flags &= ~MS_SLAVE;
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}
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if (flags & MS_SHARED) {
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type = TOMOYO_MOUNT_MAKE_SHARED_KEYWORD;
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flags &= ~MS_SHARED;
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}
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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_same_acl_head(&p1->head, &p2->head) &&
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tomoyo_same_name_union(&p1->dev_name, &p2->dev_name) &&
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tomoyo_same_name_union(&p1->dir_name, &p2->dir_name) &&
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tomoyo_same_name_union(&p1->fs_type, &p2->fs_type) &&
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tomoyo_same_number_union(&p1->flags, &p2->flags);
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}
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/**
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* tomoyo_write_mount - 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(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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