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![Prasanna Kumar Kalever](/assets/img/avatar_default.png)
Problem: On reconfigure of device, there is no way to defend if the backend storage is matching with the initial backend storage. Say, if an initial connect request for backend "pool1/image1" got mapped to /dev/nbd0 and the userspace process is terminated. A next reconfigure request within NBD_ATTR_DEAD_CONN_TIMEOUT is allowed to use /dev/nbd0 for a different backend "pool1/image2" For example, an operation like below could be dangerous: $ sudo rbd-nbd map --try-netlink rbd-pool/ext4-image /dev/nbd0 $ sudo blkid /dev/nbd0 /dev/nbd0: UUID="bfc444b4-64b1-418f-8b36-6e0d170cfc04" TYPE="ext4" $ sudo pkill -9 rbd-nbd $ sudo rbd-nbd attach --try-netlink --device /dev/nbd0 rbd-pool/xfs-image /dev/nbd0 $ sudo blkid /dev/nbd0 /dev/nbd0: UUID="d29bf343-6570-4069-a9ea-2fa156ced908" TYPE="xfs" Solution: Provide a way for userspace processes to keep some metadata to identify between the device and the backend, so that when a reconfigure request is made, we can compare and avoid such dangerous operations. With this solution, as part of the initial connect request, backend path can be stored in the sysfs per device config, so that on a reconfigure request it's easy to check if the backend path matches with the initial connect backend path. Please note, ioctl interface to nbd will not have these changes, as there won't be any reconfigure. Signed-off-by: Prasanna Kumar Kalever <prasanna.kalever@redhat.com> Reviewed-by: Xiubo Li <xiubli@redhat.com> Reviewed-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20210429102828.31248-1-prasanna.kalever@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
100 lines
2.4 KiB
C
100 lines
2.4 KiB
C
/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
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/*
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* Copyright (C) 2017 Facebook. All rights reserved.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public
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* License v2 as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public
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* License along with this program; if not, write to the
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* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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* Boston, MA 021110-1307, USA.
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*/
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#ifndef _UAPILINUX_NBD_NETLINK_H
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#define _UAPILINUX_NBD_NETLINK_H
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#define NBD_GENL_FAMILY_NAME "nbd"
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#define NBD_GENL_VERSION 0x1
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#define NBD_GENL_MCAST_GROUP_NAME "nbd_mc_group"
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/* Configuration policy attributes, used for CONNECT */
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enum {
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NBD_ATTR_UNSPEC,
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NBD_ATTR_INDEX,
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NBD_ATTR_SIZE_BYTES,
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NBD_ATTR_BLOCK_SIZE_BYTES,
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NBD_ATTR_TIMEOUT,
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NBD_ATTR_SERVER_FLAGS,
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NBD_ATTR_CLIENT_FLAGS,
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NBD_ATTR_SOCKETS,
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NBD_ATTR_DEAD_CONN_TIMEOUT,
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NBD_ATTR_DEVICE_LIST,
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NBD_ATTR_BACKEND_IDENTIFIER,
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__NBD_ATTR_MAX,
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};
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#define NBD_ATTR_MAX (__NBD_ATTR_MAX - 1)
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/*
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* This is the format for multiple devices with NBD_ATTR_DEVICE_LIST
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*
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* [NBD_ATTR_DEVICE_LIST]
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* [NBD_DEVICE_ITEM]
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* [NBD_DEVICE_INDEX]
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* [NBD_DEVICE_CONNECTED]
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*/
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enum {
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NBD_DEVICE_ITEM_UNSPEC,
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NBD_DEVICE_ITEM,
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__NBD_DEVICE_ITEM_MAX,
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};
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#define NBD_DEVICE_ITEM_MAX (__NBD_DEVICE_ITEM_MAX - 1)
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enum {
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NBD_DEVICE_UNSPEC,
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NBD_DEVICE_INDEX,
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NBD_DEVICE_CONNECTED,
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__NBD_DEVICE_MAX,
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};
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#define NBD_DEVICE_ATTR_MAX (__NBD_DEVICE_MAX - 1)
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/*
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* This is the format for multiple sockets with NBD_ATTR_SOCKETS
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*
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* [NBD_ATTR_SOCKETS]
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* [NBD_SOCK_ITEM]
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* [NBD_SOCK_FD]
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* [NBD_SOCK_ITEM]
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* [NBD_SOCK_FD]
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*/
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enum {
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NBD_SOCK_ITEM_UNSPEC,
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NBD_SOCK_ITEM,
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__NBD_SOCK_ITEM_MAX,
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};
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#define NBD_SOCK_ITEM_MAX (__NBD_SOCK_ITEM_MAX - 1)
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enum {
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NBD_SOCK_UNSPEC,
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NBD_SOCK_FD,
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__NBD_SOCK_MAX,
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};
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#define NBD_SOCK_MAX (__NBD_SOCK_MAX - 1)
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enum {
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NBD_CMD_UNSPEC,
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NBD_CMD_CONNECT,
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NBD_CMD_DISCONNECT,
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NBD_CMD_RECONFIGURE,
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NBD_CMD_LINK_DEAD,
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NBD_CMD_STATUS,
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__NBD_CMD_MAX,
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};
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#define NBD_CMD_MAX (__NBD_CMD_MAX - 1)
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#endif /* _UAPILINUX_NBD_NETLINK_H */
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