[PATCH 0/5] cifsd: introduce new SMB3 kernel server

Namjae Jeon
2021-03-22T05:23:34Z

This is the patch series for cifsd(ksmbd) kernel server.

What is cifsd(ksmbd) ?
======================

The SMB family of protocols is the most widely deployed
network filesystem protocol, the default on Windows and Macs (and even
on many phones and tablets), with clients and servers on all major
operating systems, but lacked a kernel server for Linux. For many
cases the current userspace server choices were suboptimal
either due to memory footprint, performance or difficulty integrating
well with advanced Linux features.

ksmbd is a new kernel module which implements the server-side of the SMB3 protocol.
The target is to provide optimized performance, GPLv2 SMB server, better
lease handling (distributed caching). The bigger goal is to add new
features more rapidly (e.g. RDMA aka "smbdirect", and recent encryption
and signing improvements to the protocol) which are easier to develop
on a smaller, more tightly optimized kernel server than for example
in Samba. The Samba project is much broader in scope (tools, security services,
LDAP, Active Directory Domain Controller, and a cross platform file server
for a wider variety of purposes) but the user space file server portion
of Samba has proved hard to optimize for some Linux workloads, including
for smaller devices. This is not meant to replace Samba, but rather be
an extension to allow better optimizing for Linux, and will continue to
integrate well with Samba user space tools and libraries where appropriate.
Working with the Samba team we have already made sure that the configuration
files and xattrs are in a compatible format between the kernel and
user space server.

Architecture
============

|--- ...
--------|--- ksmbd/3 - Client 3
|-------|--- ksmbd/2 - Client 2
| | ____________________________________________________
| | |- Client 1 |
<--- Socket ---|--- ksmbd/1 <<= Authentication : NTLM/NTLM2, Kerberos |
| | | | <<= SMB engine : SMB2, SMB2.1, SMB3, SMB3.0.2, |
| | | | SMB3.1.1 |
| | | |____________________________________________________|
| | |
| | |--- VFS --- Local Filesystem
| |
KERNEL |--- ksmbd/0(forker kthread)
---------------||---------------------------------------------------------------
USER ||
|| communication using NETLINK
|| ______________________________________________
|| | |
ksmbd.mountd <<= DCE/RPC(srvsvc, wkssvc, samr, lsarpc) |
^ | <<= configure shares setting, user accounts |
| |______________________________________________|
|
|------ smb.conf(config file)
|
|------ ksmbdpwd.db(user account/password file)
^
ksmbd.adduser ------------|

The subset of performance related operations(open/read/write/close etc.) belong
in kernelspace(ksmbd) and the other subset which belong to operations(DCE/RPC,
user account/share database) which are not really related with performance are
handled in userspace(ksmbd.mountd).

When the ksmbd.mountd is started, It starts up a forker thread at initialization
time and opens a dedicated port 445 for listening to SMB requests. Whenever new
clients make request, Forker thread will accept the client connection and fork
a new thread for dedicated communication channel between the client and
the server.

ksmbd feature status
====================

============================== =================================================
Feature name Status
============================== =================================================
Dialects Supported. SMB2.1 SMB3.0, SMB3.1.1 dialects
(intentionally excludes security vulnerable SMB1 dialect).
Auto Negotiation Supported.
Compound Request Supported.
Oplock Cache Mechanism Supported.
SMB2 leases(v1 lease) Supported.
Directory leases(v2 lease) Planned for future.
Multi-credits Supported.
NTLM/NTLMv2 Supported.
HMAC-SHA256 Signing Supported.
Secure negotiate Supported.
Signing Update Supported.
Pre-authentication integrity Supported.
SMB3 encryption(CCM, GCM) Supported. (CCM and GCM128 supported, GCM256 in progress)
SMB direct(RDMA) Partially Supported. SMB3 Multi-channel is required
to connect to Windows client.
SMB3 Multi-channel In Progress.
SMB3.1.1 POSIX extension Supported.
ACLs Partially Supported. only DACLs available, SACLs
(auditing) is planned for the future. For
ownership (SIDs) ksmbd generates random subauth
values(then store it to disk) and use uid/gid
get from inode as RID for local domain SID.
The current acl implementation is limited to
standalone server, not a domain member.
Integration with Samba tools is being worked on to
allow future support for running as a domain member.
Kerberos Supported.
Durable handle v1,v2 Planned for future.
Persistent handle Planned for future.
SMB2 notify Planned for future.
Sparse file support Supported.
DCE/RPC support Partially Supported. a few calls(NetShareEnumAll,
NetServerGetInfo, SAMR, LSARPC) that are needed
for file server handled via netlink interface from
ksmbd.mountd. Additional integration with Samba
tools and libraries via upcall is being investigated
to allow support for additional DCE/RPC management
calls (and future support for Witness protocol e.g.)
============================== =================================================

All features required as file server are currently implemented in ksmbd.
In particular, the implementation of SMB Direct(RDMA) is only currently
possible with ksmbd (among Linux servers)

Stability
=========

It has been proved to be stable. A significant amount of xfstests pass and
are run regularly from Linux to Linux:

http://smb3-test-rhel-75.southcentralus.cloudapp.azure.com/#/builders/8/builds/26

In addition regression tests using the broadest SMB3 functional test suite
(Samba's "smbtorture") are run on every checkin.
It has already been used by many other open source toolkits and commercial companies
that need NAS functionality. Their issues have been fixed and contributions are
applied into ksmbd. Ksmbd has been well tested and verified in the field and market.

Mailing list and repositories
=============================
- linux-cifsd-devel@lists.sourceforge.net
- https://github.com/smfrench/smb3-kernel/tree/cifsd-for-next
- https://github.com/cifsd-team/cifsd (out-of-tree)
- https://github.com/cifsd-team/ksmbd-tools

How to run ksmbd
================

a. Download ksmbd-tools and compile them.
- https://github.com/cifsd-team/ksmbd-tools

b. Create user/password for SMB share.

# mkdir /etc/ksmbd/
# ksmbd.adduser -a <Enter USERNAME for SMB share access>

c. Create /etc/ksmbd/smb.conf file, add SMB share in smb.conf file
- Refer smb.conf.example and Documentation/configuration.txt
in ksmbd-tools

d. Insert ksmbd.ko module

# insmod ksmbd.ko

e. Start ksmbd user space daemon
# ksmbd.mountd

f. Access share from Windows or Linux using SMB
e.g. "mount -t cifs //server/share /mnt ..."

v0:
- fix a handful of spelling mistakes (Colin Ian King)
- fix a precedence bug in parse_dacl() (Dan Carpenter)
- fix a IS_ERR() vs NULL bug (Dan Carpenter)
- fix a use after free on error path (Dan Carpenter)
- update cifsd.rst Documentation
- remove unneeded FIXME comments
- fix static checker warnings (Dan Carpenter)
- fix WARNING: unmet direct dependencies detected for CRYPTO_ARC4 (Randy Dunlap)
- uniquify extract_sharename() (Stephen Rothwell)
- fix WARNING: document isn't included in any toctree (Stephen Rothwell)
- fix WARNING: Title overline too short (Stephen Rothwell)
- fix incorrect function comments

Namjae Jeon (5):
cifsd: add server handler and tranport layers
cifsd: add server-side procedures for SMB3
cifsd: add file operations
cifsd: add Kconfig and Makefile
MAINTAINERS: add cifsd kernel server

Documentation/filesystems/cifs/cifsd.rst | 180 +
Documentation/filesystems/cifs/index.rst | 10 +
Documentation/filesystems/index.rst | 2 +-
MAINTAINERS | 12 +-
fs/Kconfig | 1 +
fs/Makefile | 1 +
fs/cifsd/Kconfig | 64 +
fs/cifsd/Makefile | 13 +
fs/cifsd/asn1.c | 702 ++
fs/cifsd/asn1.h | 29 +
fs/cifsd/auth.c | 1348 ++++
fs/cifsd/auth.h | 90 +
fs/cifsd/buffer_pool.c | 292 +
fs/cifsd/buffer_pool.h | 28 +
fs/cifsd/connection.c | 416 ++
fs/cifsd/connection.h | 212 +
fs/cifsd/crypto_ctx.c | 287 +
fs/cifsd/crypto_ctx.h | 77 +
fs/cifsd/glob.h | 67 +
fs/cifsd/ksmbd_server.h | 285 +
fs/cifsd/ksmbd_work.c | 93 +
fs/cifsd/ksmbd_work.h | 124 +
fs/cifsd/mgmt/ksmbd_ida.c | 69 +
fs/cifsd/mgmt/ksmbd_ida.h | 41 +
fs/cifsd/mgmt/share_config.c | 238 +
fs/cifsd/mgmt/share_config.h | 81 +
fs/cifsd/mgmt/tree_connect.c | 128 +
fs/cifsd/mgmt/tree_connect.h | 56 +
fs/cifsd/mgmt/user_config.c | 69 +
fs/cifsd/mgmt/user_config.h | 66 +
fs/cifsd/mgmt/user_session.c | 344 +
fs/cifsd/mgmt/user_session.h | 105 +
fs/cifsd/misc.c | 296 +
fs/cifsd/misc.h | 38 +
fs/cifsd/ndr.c | 344 +
fs/cifsd/ndr.h | 21 +
fs/cifsd/netmisc.c | 46 +
fs/cifsd/nterr.c | 674 ++
fs/cifsd/nterr.h | 552 ++
fs/cifsd/ntlmssp.h | 169 +
fs/cifsd/oplock.c | 1681 +++++
fs/cifsd/oplock.h | 138 +
fs/cifsd/server.c | 632 ++
fs/cifsd/server.h | 62 +
fs/cifsd/smb2misc.c | 458 ++
fs/cifsd/smb2ops.c | 300 +
fs/cifsd/smb2pdu.c | 8452 ++++++++++++++++++++++
fs/cifsd/smb2pdu.h | 1649 +++++
fs/cifsd/smb_common.c | 667 ++
fs/cifsd/smb_common.h | 546 ++
fs/cifsd/smbacl.c | 1324 ++++
fs/cifsd/smbacl.h | 202 +
fs/cifsd/smberr.h | 235 +
fs/cifsd/smbfsctl.h | 90 +
fs/cifsd/smbstatus.h | 1822 +++++
fs/cifsd/time_wrappers.h | 34 +
fs/cifsd/transport_ipc.c | 897 +++
fs/cifsd/transport_ipc.h | 62 +
fs/cifsd/transport_rdma.c | 2051 ++++++
fs/cifsd/transport_rdma.h | 61 +
fs/cifsd/transport_tcp.c | 625 ++
fs/cifsd/transport_tcp.h | 13 +
fs/cifsd/unicode.c | 391 +
fs/cifsd/unicode.h | 374 +
fs/cifsd/uniupr.h | 268 +
fs/cifsd/vfs.c | 1989 +++++
fs/cifsd/vfs.h | 314 +
fs/cifsd/vfs_cache.c | 851 +++
fs/cifsd/vfs_cache.h | 213 +
69 files changed, 34069 insertions(+), 2 deletions(-)
create mode 100644 Documentation/filesystems/cifs/cifsd.rst
create mode 100644 Documentation/filesystems/cifs/index.rst
create mode 100644 fs/cifsd/Kconfig
create mode 100644 fs/cifsd/Makefile
create mode 100644 fs/cifsd/asn1.c
create mode 100644 fs/cifsd/asn1.h
create mode 100644 fs/cifsd/auth.c
create mode 100644 fs/cifsd/auth.h
create mode 100644 fs/cifsd/buffer_pool.c
create mode 100644 fs/cifsd/buffer_pool.h
create mode 100644 fs/cifsd/connection.c
create mode 100644 fs/cifsd/connection.h
create mode 100644 fs/cifsd/crypto_ctx.c
create mode 100644 fs/cifsd/crypto_ctx.h
create mode 100644 fs/cifsd/glob.h
create mode 100644 fs/cifsd/ksmbd_server.h
create mode 100644 fs/cifsd/ksmbd_work.c
create mode 100644 fs/cifsd/ksmbd_work.h
create mode 100644 fs/cifsd/mgmt/ksmbd_ida.c
create mode 100644 fs/cifsd/mgmt/ksmbd_ida.h
create mode 100644 fs/cifsd/mgmt/share_config.c
create mode 100644 fs/cifsd/mgmt/share_config.h
create mode 100644 fs/cifsd/mgmt/tree_connect.c
create mode 100644 fs/cifsd/mgmt/tree_connect.h
create mode 100644 fs/cifsd/mgmt/user_config.c
create mode 100644 fs/cifsd/mgmt/user_config.h
create mode 100644 fs/cifsd/mgmt/user_session.c
create mode 100644 fs/cifsd/mgmt/user_session.h
create mode 100644 fs/cifsd/misc.c
create mode 100644 fs/cifsd/misc.h
create mode 100644 fs/cifsd/ndr.c
create mode 100644 fs/cifsd/ndr.h
create mode 100644 fs/cifsd/netmisc.c
create mode 100644 fs/cifsd/nterr.c
create mode 100644 fs/cifsd/nterr.h
create mode 100644 fs/cifsd/ntlmssp.h
create mode 100644 fs/cifsd/oplock.c
create mode 100644 fs/cifsd/oplock.h
create mode 100644 fs/cifsd/server.c
create mode 100644 fs/cifsd/server.h
create mode 100644 fs/cifsd/smb2misc.c
create mode 100644 fs/cifsd/smb2ops.c
create mode 100644 fs/cifsd/smb2pdu.c
create mode 100644 fs/cifsd/smb2pdu.h
create mode 100644 fs/cifsd/smb_common.c
create mode 100644 fs/cifsd/smb_common.h
create mode 100644 fs/cifsd/smbacl.c
create mode 100644 fs/cifsd/smbacl.h
create mode 100644 fs/cifsd/smberr.h
create mode 100644 fs/cifsd/smbfsctl.h
create mode 100644 fs/cifsd/smbstatus.h
create mode 100644 fs/cifsd/time_wrappers.h
create mode 100644 fs/cifsd/transport_ipc.c
create mode 100644 fs/cifsd/transport_ipc.h
create mode 100644 fs/cifsd/transport_rdma.c
create mode 100644 fs/cifsd/transport_rdma.h
create mode 100644 fs/cifsd/transport_tcp.c
create mode 100644 fs/cifsd/transport_tcp.h
create mode 100644 fs/cifsd/unicode.c
create mode 100644 fs/cifsd/unicode.h
create mode 100644 fs/cifsd/uniupr.h
create mode 100644 fs/cifsd/vfs.c
create mode 100644 fs/cifsd/vfs.h
create mode 100644 fs/cifsd/vfs_cache.c
create mode 100644 fs/cifsd/vfs_cache.h

--
2.17.1