1 # SPDX-License-Identifier: GPL-2.0-only
3 tristate "SMB3 and CIFS support (advanced network filesystem)"
23 This is the client VFS module for the SMB3 family of network file
24 protocols (including the most recent, most secure dialect SMB3.1.1).
25 This module also includes support for earlier dialects such as
26 SMB2.1, SMB2 and even the old Common Internet File System (CIFS)
27 protocol. CIFS was the successor to the original network filesystem
28 protocol, Server Message Block (SMB ie SMB1), the native file sharing
29 mechanism for most early PC operating systems.
31 The SMB3.1.1 protocol is supported by most modern operating systems
32 and NAS appliances (e.g. Samba, Windows 11, Windows Server 2022,
33 MacOS) and even in the cloud (e.g. Microsoft Azure) and also by the
34 Linux kernel server, ksmbd. Support for the older CIFS protocol was
35 included in Windows NT4, 2000 and XP (and later). Use of dialects
36 older than SMB2.1 is often discouraged on public networks.
37 This module also provides limited support for OS/2 and Windows ME
38 and similar very old servers.
40 This module provides an advanced network file system client for
41 mounting to SMB3 (and CIFS) compliant servers. It includes support
42 for DFS (hierarchical name space), secure per-user session
43 establishment via Kerberos or NTLMv2, RDMA (smbdirect), advanced
44 security features, per-share encryption, packet-signing, snapshots,
45 directory leases, safe distributed caching (leases), multichannel,
46 Unicode and other internationalization improvements.
48 In general, the default dialects, SMB3 and later, enable better
49 performance, security and features, than would be possible with CIFS.
51 If you need to mount to Samba, Azure, ksmbd, Macs or Windows from this
55 bool "Extended statistics"
59 Enabling this option will allow more detailed statistics on SMB
60 request timing to be displayed in /proc/fs/cifs/DebugData and also
61 allow optional logging of slow responses to dmesg (depending on the
62 value of /proc/fs/cifs/cifsFYI). See Documentation/admin-guide/cifs/usage.rst
63 for more details. These additional statistics may have a minor effect
64 on performance and memory utilization.
68 config CIFS_ALLOW_INSECURE_LEGACY
69 bool "Support legacy servers which use less secure dialects"
73 Modern dialects, SMB2.1 and later (including SMB3 and 3.1.1), have
74 additional security features, including protection against
75 man-in-the-middle attacks and stronger crypto hashes, so the use
76 of legacy dialects (SMB1/CIFS and SMB2.0) is discouraged.
78 Disabling this option prevents users from using vers=1.0 or vers=2.0
79 on mounts with cifs.ko
84 bool "Kerberos/SPNEGO advanced session setup"
87 Enables an upcall mechanism for CIFS which accesses userspace helper
88 utilities to provide SPNEGO packaged (RFC 4178) Kerberos tickets
89 which are needed to mount to certain secure servers (for which more
90 secure Kerberos authentication is required). If unsure, say Y.
93 bool "CIFS extended attributes"
96 Extended attributes are name:value pairs associated with inodes by
97 the kernel or by users (see the attr(5) manual page for details).
98 CIFS maps the name of extended attributes beginning with the user
99 namespace prefix to SMB/CIFS EAs. EAs are stored on Windows
100 servers without the user namespace prefix, but their names are
101 seen by Linux cifs clients prefaced by the user namespace prefix.
102 The system namespace (used by some filesystems to store ACLs) is
103 not supported at this time.
108 bool "CIFS POSIX Extensions"
109 depends on CIFS && CIFS_ALLOW_INSECURE_LEGACY && CIFS_XATTR
111 Enabling this option will cause the cifs client to attempt to
112 negotiate a feature of the older cifs dialect with servers, such as
113 Samba 3.0.5 or later, that optionally can handle more POSIX like
114 (rather than Windows like) file behavior. It also enables support
115 for POSIX ACLs (getfacl and setfacl) to servers (such as Samba 3.10
116 and later) which can negotiate CIFS POSIX ACL support. This config
117 option is not needed when mounting with SMB3.1.1. If unsure, say N.
120 bool "Enable CIFS debugging routines"
124 Enabling this option adds helpful debugging messages to
125 the cifs code which increases the size of the cifs module.
129 bool "Enable additional CIFS debugging routines"
130 depends on CIFS_DEBUG
132 Enabling this option adds a few more debugging routines
133 to the cifs code which slightly increases the size of
134 the cifs module and can cause additional logging of debug
135 messages in some error paths, slowing performance. This
136 option can be turned off unless you are debugging
137 cifs problems. If unsure, say N.
139 config CIFS_DEBUG_DUMP_KEYS
140 bool "Dump encryption keys for offline decryption (Unsafe)"
141 depends on CIFS_DEBUG
143 Enabling this will dump the encryption and decryption keys
144 used to communicate on an encrypted share connection on the
145 console. This allows Wireshark to decrypt and dissect
146 encrypted network captures. Enable this carefully.
149 config CIFS_DFS_UPCALL
150 bool "DFS feature support"
153 Distributed File System (DFS) support is used to access shares
154 transparently in an enterprise name space, even if the share
155 moves to a different server. This feature also enables
156 an upcall mechanism for CIFS which contacts userspace helper
157 utilities to provide server name resolution (host names to
158 IP addresses) which is needed in order to reconnect to
159 servers if their addresses change or for implicit mounts of
160 DFS junction points. If unsure, say Y.
162 config CIFS_SWN_UPCALL
163 bool "SWN feature support"
166 The Service Witness Protocol (SWN) is used to get notifications
167 from a highly available server of resource state changes. This
168 feature enables an upcall mechanism for CIFS which contacts a
169 userspace daemon to establish the DCE/RPC connection to retrieve
170 the cluster available interfaces and resource change notifications.
173 config CIFS_NFSD_EXPORT
174 bool "Allow nfsd to export CIFS file system"
175 depends on CIFS && BROKEN
177 Allows NFS server to export a CIFS mounted share (nfsd over cifs)
181 config CIFS_SMB_DIRECT
182 bool "SMB Direct support"
183 depends on CIFS=m && INFINIBAND && INFINIBAND_ADDR_TRANS || CIFS=y && INFINIBAND=y && INFINIBAND_ADDR_TRANS=y
185 Enables SMB Direct support for SMB 3.0, 3.02 and 3.1.1.
186 SMB Direct allows transferring SMB packets over RDMA. If unsure,
190 bool "Provide CIFS client caching support"
191 depends on CIFS=m && FSCACHE || CIFS=y && FSCACHE=y
193 Makes CIFS FS-Cache capable. Say Y here if you want your CIFS data
194 to be cached locally on disk through the general filesystem cache
195 manager. If unsure, say N.
198 bool "SMB root file system (Experimental)"
199 depends on CIFS=y && IP_PNP
201 Enables root file system support over SMB protocol.
203 Most people say N here.