xref: /linux/fs/smb/client/Kconfig (revision 4b4c6fdb25de4edc0a34b1b93cccb439e00e1f35)

# SPDX-License-Identifier: GPL-2.0-only
config CIFS
	tristate "SMB3 and CIFS support (advanced network filesystem)"
	depends on INET
	select NLS
	select NLS_UCS2_UTILS
	select CRYPTO
	select CRYPTO_MD5
	select CRYPTO_SHA256
	select CRYPTO_SHA512
	select CRYPTO_CMAC
	select CRYPTO_HMAC
	select CRYPTO_AEAD2
	select CRYPTO_CCM
	select CRYPTO_GCM
	select CRYPTO_ECB
	select CRYPTO_AES
	select CRYPTO_LIB_ARC4
	select CRYPTO_LIB_SHA256
	select CRYPTO_LIB_SHA512
	select KEYS
	select DNS_RESOLVER
	select ASN1
	select OID_REGISTRY
	select NETFS_SUPPORT
	help
	  This is the client VFS module for the SMB3 family of network file
	  protocols (including the most recent, most secure dialect SMB3.1.1).
	  This module also includes support for earlier dialects such as
	  SMB2.1, SMB2 and even the old Common Internet File System (CIFS)
	  protocol.  CIFS was the successor to the original network filesystem
	  protocol, Server Message Block (SMB ie SMB1), the native file sharing
	  mechanism for most early PC operating systems.

	  The SMB3.1.1 protocol is supported by most modern operating systems
	  and NAS appliances (e.g. Samba, Windows 11, Windows Server 2022,
	  MacOS) and even in the cloud (e.g. Microsoft Azure) and also by the
	  Linux kernel server, ksmbd.  Support for the older CIFS protocol was
	  included in Windows NT4, 2000 and XP (and later). Use of dialects
	  older than SMB2.1 is often discouraged on public networks.
	  This module also provides limited support for OS/2 and Windows ME
	  and similar very old servers.

	  This module provides an advanced network file system client for
	  mounting to SMB3 (and CIFS) compliant servers.  It includes support
	  for DFS (hierarchical name space), secure per-user session
	  establishment via Kerberos or NTLMv2, RDMA (smbdirect), advanced
	  security features, per-share encryption, packet-signing, snapshots,
	  directory leases, safe distributed caching (leases), multichannel,
	  Unicode and other internationalization improvements.

	  In general, the default dialects, SMB3 and later, enable better
	  performance, security and features, than would be possible with CIFS.

	  If you need to mount to Samba, Azure, ksmbd, Macs or Windows from this
	  machine, say Y.

config CIFS_STATS2
	bool "Extended statistics"
	depends on CIFS
	default y
	help
	  Enabling this option will allow more detailed statistics on SMB
	  request timing to be displayed in /proc/fs/cifs/DebugData and also
	  allow optional logging of slow responses to dmesg (depending on the
	  value of /proc/fs/cifs/cifsFYI). See Documentation/admin-guide/cifs/usage.rst
	  for more details. These additional statistics may have a minor effect
	  on performance and memory utilization.

	  If unsure, say Y.

config CIFS_ALLOW_INSECURE_LEGACY
	bool "Support legacy servers which use less secure dialects"
	depends on CIFS
	default y
	help
	  Modern dialects, SMB2.1 and later (including SMB3 and 3.1.1), have
	  additional security features, including protection against
	  man-in-the-middle attacks and stronger crypto hashes, so the use
	  of legacy dialects (SMB1/CIFS and SMB2.0) is discouraged.

	  Disabling this option prevents users from using vers=1.0 or vers=2.0
	  on mounts with cifs.ko

	  If unsure, say Y.

config CIFS_UPCALL
	bool "Kerberos/SPNEGO advanced session setup"
	depends on CIFS
	help
	  Enables an upcall mechanism for CIFS which accesses userspace helper
	  utilities to provide SPNEGO packaged (RFC 4178) Kerberos tickets
	  which are needed to mount to certain secure servers (for which more
	  secure Kerberos authentication is required). If unsure, say Y.

config CIFS_XATTR
	bool "CIFS extended attributes"
	depends on CIFS
	help
	  Extended attributes are name:value pairs associated with inodes by
	  the kernel or by users (see the attr(5) manual page for details).
	  CIFS maps the name of extended attributes beginning with the user
	  namespace prefix to SMB/CIFS EAs.  EAs are stored on Windows
	  servers without the user namespace prefix, but their names are
	  seen by Linux cifs clients prefaced by the user namespace prefix.
	  The system namespace (used by some filesystems to store ACLs) is
	  not supported at this time.

	  If unsure, say Y.

config CIFS_POSIX
	bool "CIFS POSIX Extensions"
	depends on CIFS && CIFS_ALLOW_INSECURE_LEGACY && CIFS_XATTR
	help
	  Enabling this option will cause the cifs client to attempt to
	  negotiate a feature of the older cifs dialect with servers, such as
	  Samba 3.0.5 or later, that optionally can handle more POSIX like
	  (rather than Windows like) file behavior.  It also enables support
	  for POSIX ACLs (getfacl and setfacl) to servers (such as Samba 3.10
	  and later) which can negotiate CIFS POSIX ACL support.  This config
	  option is not needed when mounting with SMB3.1.1. If unsure, say N.

config CIFS_DEBUG
	bool "Enable CIFS debugging routines"
	default y
	depends on CIFS
	help
	  Enabling this option adds helpful debugging messages to
	  the cifs code which increases the size of the cifs module.
	  If unsure, say Y.

config CIFS_DEBUG2
	bool "Enable additional CIFS debugging routines"
	depends on CIFS_DEBUG
	help
	  Enabling this option adds a few more debugging routines
	  to the cifs code which slightly increases the size of
	  the cifs module and can cause additional logging of debug
	  messages in some error paths, slowing performance. This
	  option can be turned off unless you are debugging
	  cifs problems.  If unsure, say N.

config CIFS_DEBUG_DUMP_KEYS
	bool "Dump encryption keys for offline decryption (Unsafe)"
	depends on CIFS_DEBUG
	help
	  Enabling this will dump the encryption and decryption keys
	  used to communicate on an encrypted share connection on the
	  console. This allows Wireshark to decrypt and dissect
	  encrypted network captures. Enable this carefully.
	  If unsure, say N.

config CIFS_DFS_UPCALL
	bool "DFS feature support"
	depends on CIFS
	help
	  Distributed File System (DFS) support is used to access shares
	  transparently in an enterprise name space, even if the share
	  moves to a different server.  This feature also enables
	  an upcall mechanism for CIFS which contacts userspace helper
	  utilities to provide server name resolution (host names to
	  IP addresses) which is needed in order to reconnect to
	  servers if their addresses change or for implicit mounts of
	  DFS junction points. If unsure, say Y.

config CIFS_SWN_UPCALL
	bool "SWN feature support"
	depends on CIFS
	help
	  The Service Witness Protocol (SWN) is used to get notifications
	  from a highly available server of resource state changes. This
	  feature enables an upcall mechanism for CIFS which contacts a
	  userspace daemon to establish the DCE/RPC connection to retrieve
	  the cluster available interfaces and resource change notifications.
	  If unsure, say Y.

config CIFS_NFSD_EXPORT
	bool "Allow nfsd to export CIFS file system"
	depends on CIFS && BROKEN
	help
	  Allows NFS server to export a CIFS mounted share (nfsd over cifs)

if CIFS

config CIFS_SMB_DIRECT
	bool "SMB Direct support"
	depends on CIFS=m && INFINIBAND && INFINIBAND_ADDR_TRANS || CIFS=y && INFINIBAND=y && INFINIBAND_ADDR_TRANS=y
	help
	  Enables SMB Direct support for SMB 3.0, 3.02 and 3.1.1.
	  SMB Direct allows transferring SMB packets over RDMA. If unsure,
	  say Y.

config CIFS_FSCACHE
	bool "Provide CIFS client caching support"
	depends on CIFS=m && FSCACHE || CIFS=y && FSCACHE=y
	help
	  Makes CIFS FS-Cache capable. Say Y here if you want your CIFS data
	  to be cached locally on disk through the general filesystem cache
	  manager. If unsure, say N.

config CIFS_ROOT
	bool "SMB root file system (Experimental)"
	depends on CIFS=y && IP_PNP
	help
	  Enables root file system support over SMB protocol.

	  Most people say N here.

config CIFS_COMPRESSION
	bool "SMB message compression (Experimental)"
	depends on CIFS
	default n
	help
	  Enables over-the-wire message compression for SMB 3.1.1
	  mounts when negotiated with the server.

	  Only write requests with data size >= PAGE_SIZE will be
	  compressed to avoid wasting resources.

	  Say Y here if you want SMB traffic to be compressed.
	  If unsure, say N.

endif