Re: [PATCH v2 00/10] cifsd: introduce new SMB3 kernel server

From: J. Bruce Fields
Date: Wed Apr 28 2021 - 15:18:35 EST


On Thu, Apr 22, 2021 at 09:28:14AM +0900, Namjae Jeon wrote:
> This is the patch series for cifsd(ksmbd) kernel server.

Looks like this series probably isn't bisectable. E.g. while looking at
the ACL code I noticed ksmbd_vfs_setxattr is defined in a later patch
than it's first used in.

I know the requirement that everything build and run after each
individual patch in the series is tough to meet when introducing a whole
new subsystem. I'm sure it's still possible, but I don't know what the
usual practice is in these cases.

--b.

>
> 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/32
>
> 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@xxxxxxxxxxxxxxxxxxxxx
> - 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 ..."
>
>
> v2:
> - fix an error code in smb2_read(). (Dan Carpenter)
> - fix error handling in ksmbd_server_init() (Dan Carpenter)
> - remove redundant assignment to variable err. (Colin Ian King)
> - remove unneeded macros.
> - fix wrong use of rw semaphore in __session_create().
> - use kmalloc() for small allocations.
> - add the check to work file lock and rename behaviors like Windows
> unless POSIX extensions are negotiated.
> - clean-up codes using chechpatch.pl --strict.
> - merge time_wrappers.h into smb_common.h.
> - fix wrong prototype in comment (kernel test robot).
> - fix implicit declaration of function 'groups_alloc' (kernel test robot).
> - fix implicit declaration of function 'locks_alloc_lock' (kernel test robot).
> - remove smack inherit leftovers.
> - remove calling d_path in error paths.
> - handle unhashed dentry in ksmbd_vfs_mkdir.
> - use file_inode() instead of d_inode().
> - remove useless error handling in ksmbd_vfs_read.
> - use xarray instead of linked list for tree connect list.
> - remove stale prototype and variables.
> - fix memory leak when loop ends (coverity-bot, Muhammad Usama Anjum).
> - use kfree to free memory allocated by kmalloc or kzalloc (Muhammad Usama Anjum).
> - fix memdup.cocci warnings (kernel test robot)
> - remove wrappers of kvmalloc/kvfree.
> - change the reference to configuration.txt (Mauro Carvalho Chehab).
> - prevent a integer overflow in wm_alloc().
> - select SG_POOL for SMB_SERVER_SMBDIRECT. (Zhang Xiaoxu).
> - remove unused including <linux/version.h> (Tian Tao).
> - declare ida statically.
> - add the check if parent is stable by unexpected rename.
> - get parent dentry from child in ksmbd_vfs_remove_file().
> - re-implement ksmbd_vfs_kern_path.
> - fix reference count decrement of unclaimed file in __ksmbd_lookup_fd.
> - remove smb2_put_name(). (Marios Makassikis).
> - remove unused smberr.h, nterr.c and netmisc.c.
> - fix potential null-ptr-deref in smb2_open() (Marios Makassikis).
> - use d_inode().
> - remove the dead code of unimplemented durable handle.
> - use the generic one in lib/asn1_decoder.c
>
> v1:
> - 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 warning: variable 'total_ace_size' and 'posix_ccontext'set but not used (kernel test rotbot)
> - fix incorrect function comments (kernel test robot)
>
> Namjae Jeon (10):
> cifsd: add document
> cifsd: add server handler
> cifsd: add trasport layers
> cifsd: add authentication
> cifsd: add smb3 engine part 1
> cifsd: add smb3 engine part 2
> cifsd: add oplock/lease cache mechanism
> cifsd: add file operations
> cifsd: add Kconfig and Makefile
> MAINTAINERS: add cifsd kernel server
>
> Documentation/filesystems/cifs/cifsd.rst | 152 +
> Documentation/filesystems/cifs/index.rst | 10 +
> Documentation/filesystems/index.rst | 2 +-
> MAINTAINERS | 12 +-
> fs/Kconfig | 1 +
> fs/Makefile | 1 +
> fs/cifsd/Kconfig | 67 +
> fs/cifsd/Makefile | 17 +
> fs/cifsd/asn1.c | 352 +
> fs/cifsd/asn1.h | 29 +
> fs/cifsd/auth.c | 1323 ++++
> fs/cifsd/auth.h | 90 +
> fs/cifsd/buffer_pool.c | 264 +
> fs/cifsd/buffer_pool.h | 20 +
> fs/cifsd/connection.c | 411 ++
> fs/cifsd/connection.h | 208 +
> fs/cifsd/crypto_ctx.c | 286 +
> fs/cifsd/crypto_ctx.h | 77 +
> fs/cifsd/glob.h | 64 +
> fs/cifsd/ksmbd_server.h | 283 +
> fs/cifsd/ksmbd_work.c | 93 +
> fs/cifsd/ksmbd_work.h | 110 +
> fs/cifsd/mgmt/ksmbd_ida.c | 48 +
> fs/cifsd/mgmt/ksmbd_ida.h | 34 +
> fs/cifsd/mgmt/share_config.c | 239 +
> fs/cifsd/mgmt/share_config.h | 81 +
> fs/cifsd/mgmt/tree_connect.c | 122 +
> fs/cifsd/mgmt/tree_connect.h | 56 +
> fs/cifsd/mgmt/user_config.c | 70 +
> fs/cifsd/mgmt/user_config.h | 66 +
> fs/cifsd/mgmt/user_session.c | 328 +
> fs/cifsd/mgmt/user_session.h | 103 +
> fs/cifsd/misc.c | 340 +
> fs/cifsd/misc.h | 44 +
> fs/cifsd/ndr.c | 347 +
> fs/cifsd/ndr.h | 21 +
> fs/cifsd/nterr.h | 545 ++
> fs/cifsd/ntlmssp.h | 169 +
> fs/cifsd/oplock.c | 1667 +++++
> fs/cifsd/oplock.h | 133 +
> fs/cifsd/server.c | 631 ++
> fs/cifsd/server.h | 60 +
> fs/cifsd/smb2misc.c | 435 ++
> fs/cifsd/smb2ops.c | 300 +
> fs/cifsd/smb2pdu.c | 8069 ++++++++++++++++++++++
> fs/cifsd/smb2pdu.h | 1646 +++++
> fs/cifsd/smb_common.c | 652 ++
> fs/cifsd/smb_common.h | 544 ++
> fs/cifsd/smbacl.c | 1317 ++++
> fs/cifsd/smbacl.h | 201 +
> fs/cifsd/smbfsctl.h | 90 +
> fs/cifsd/smbstatus.h | 1822 +++++
> fs/cifsd/spnego_negtokeninit.asn1 | 43 +
> fs/cifsd/spnego_negtokentarg.asn1 | 19 +
> fs/cifsd/transport_ipc.c | 881 +++
> fs/cifsd/transport_ipc.h | 54 +
> fs/cifsd/transport_rdma.c | 2034 ++++++
> fs/cifsd/transport_rdma.h | 61 +
> fs/cifsd/transport_tcp.c | 618 ++
> fs/cifsd/transport_tcp.h | 13 +
> fs/cifsd/unicode.c | 383 +
> fs/cifsd/unicode.h | 356 +
> fs/cifsd/uniupr.h | 268 +
> fs/cifsd/vfs.c | 1995 ++++++
> fs/cifsd/vfs.h | 273 +
> fs/cifsd/vfs_cache.c | 683 ++
> fs/cifsd/vfs_cache.h | 185 +
> 67 files changed, 31916 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/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/smbfsctl.h
> create mode 100644 fs/cifsd/smbstatus.h
> create mode 100644 fs/cifsd/spnego_negtokeninit.asn1
> create mode 100644 fs/cifsd/spnego_negtokentarg.asn1
> 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
>