2 tristate "SMB3 and CIFS support (advanced network filesystem)"
18 This is the client VFS module for the SMB3 family of NAS protocols,
19 (including support for the most recent, most secure dialect SMB3.1.1)
20 as well as for earlier dialects such as SMB2.1, SMB2 and the older
21 Common Internet File System (CIFS) protocol. CIFS was the successor
22 to the original dialect, the Server Message Block (SMB) protocol, the
23 native file sharing mechanism for most early PC operating systems.
25 The SMB3 protocol is supported by most modern operating systems
26 and NAS appliances (e.g. Samba, Windows 10, Windows Server 2016,
27 MacOS) and even in the cloud (e.g. Microsoft Azure).
28 The older CIFS protocol was included in Windows NT4, 2000 and XP (and
29 later) as well by Samba (which provides excellent CIFS and SMB3
30 server support for Linux and many other operating systems). Use of
31 dialects older than SMB2.1 is often discouraged on public networks.
32 This module also provides limited support for OS/2 and Windows ME
33 and similar very old servers.
35 This module provides an advanced network file system client
36 for mounting to SMB3 (and CIFS) compliant servers. It includes
37 support for DFS (hierarchical name space), secure per-user
38 session establishment via Kerberos or NTLM or NTLMv2, RDMA
39 (smbdirect), advanced security features, per-share encryption,
40 directory leases, safe distributed caching (oplock), optional packet
41 signing, Unicode and other internationalization improvements.
43 In general, the default dialects, SMB3 and later, enable better
44 performance, security and features, than would be possible with CIFS.
45 Note that when mounting to Samba, due to the CIFS POSIX extensions,
46 CIFS mounts can provide slightly better POSIX compatibility
47 than SMB3 mounts. SMB2/SMB3 mount options are also
48 slightly simpler (compared to CIFS) due to protocol improvements.
50 If you need to mount to Samba, Azure, Macs or Windows from this machine, say Y.
53 bool "Extended statistics"
56 Enabling this option will allow more detailed statistics on SMB
57 request timing to be displayed in /proc/fs/cifs/DebugData and also
58 allow optional logging of slow responses to dmesg (depending on the
59 value of /proc/fs/cifs/cifsFYI, see fs/cifs/README for more details).
60 These additional statistics may have a minor effect on performance
61 and memory utilization.
63 Unless you are a developer or are doing network performance analysis
66 config CIFS_ALLOW_INSECURE_LEGACY
67 bool "Support legacy servers which use less secure dialects"
71 Modern dialects, SMB2.1 and later (including SMB3 and 3.1.1), have
72 additional security features, including protection against
73 man-in-the-middle attacks and stronger crypto hashes, so the use
74 of legacy dialects (SMB1/CIFS and SMB2.0) is discouraged.
76 Disabling this option prevents users from using vers=1.0 or vers=2.0
77 on mounts with cifs.ko
81 config CIFS_WEAK_PW_HASH
82 bool "Support legacy servers which use weaker LANMAN security"
83 depends on CIFS && CIFS_ALLOW_INSECURE_LEGACY
85 Modern CIFS servers including Samba and most Windows versions
86 (since 1997) support stronger NTLM (and even NTLMv2 and Kerberos)
87 security mechanisms. These hash the password more securely
88 than the mechanisms used in the older LANMAN version of the
89 SMB protocol but LANMAN based authentication is needed to
90 establish sessions with some old SMB servers.
92 Enabling this option allows the cifs module to mount to older
93 LANMAN based servers such as OS/2 and Windows 95, but such
94 mounts may be less secure than mounts using NTLM or more recent
95 security mechanisms if you are on a public network. Unless you
96 have a need to access old SMB servers (and are on a private
97 network) you probably want to say N. Even if this support
98 is enabled in the kernel build, LANMAN authentication will not be
99 used automatically. At runtime LANMAN mounts are disabled but
100 can be set to required (or optional) either in
101 /proc/fs/cifs (see fs/cifs/README for more detail) or via an
102 option on the mount command. This support is disabled by
103 default in order to reduce the possibility of a downgrade
109 bool "Kerberos/SPNEGO advanced session setup"
110 depends on CIFS && KEYS
113 Enables an upcall mechanism for CIFS which accesses userspace helper
114 utilities to provide SPNEGO packaged (RFC 4178) Kerberos tickets
115 which are needed to mount to certain secure servers (for which more
116 secure Kerberos authentication is required). If unsure, say Y.
119 bool "CIFS extended attributes"
122 Extended attributes are name:value pairs associated with inodes by
123 the kernel or by users (see the attr(5) manual page for details).
124 CIFS maps the name of extended attributes beginning with the user
125 namespace prefix to SMB/CIFS EAs. EAs are stored on Windows
126 servers without the user namespace prefix, but their names are
127 seen by Linux cifs clients prefaced by the user namespace prefix.
128 The system namespace (used by some filesystems to store ACLs) is
129 not supported at this time.
134 bool "CIFS POSIX Extensions"
135 depends on CIFS_XATTR
137 Enabling this option will cause the cifs client to attempt to
138 negotiate a newer dialect with servers, such as Samba 3.0.5
139 or later, that optionally can handle more POSIX like (rather
140 than Windows like) file behavior. It also enables
141 support for POSIX ACLs (getfacl and setfacl) to servers
142 (such as Samba 3.10 and later) which can negotiate
143 CIFS POSIX ACL support. If unsure, say N.
146 bool "Provide CIFS ACL support"
147 depends on CIFS_XATTR && KEYS
149 Allows fetching CIFS/NTFS ACL from the server. The DACL blob
150 is handed over to the application/caller. See the man
151 page for getcifsacl for more information. If unsure, say Y.
154 bool "Enable CIFS debugging routines"
158 Enabling this option adds helpful debugging messages to
159 the cifs code which increases the size of the cifs module.
162 bool "Enable additional CIFS debugging routines"
163 depends on CIFS_DEBUG
165 Enabling this option adds a few more debugging routines
166 to the cifs code which slightly increases the size of
167 the cifs module and can cause additional logging of debug
168 messages in some error paths, slowing performance. This
169 option can be turned off unless you are debugging
170 cifs problems. If unsure, say N.
172 config CIFS_DEBUG_DUMP_KEYS
173 bool "Dump encryption keys for offline decryption (Unsafe)"
174 depends on CIFS_DEBUG
176 Enabling this will dump the encryption and decryption keys
177 used to communicate on an encrypted share connection on the
178 console. This allows Wireshark to decrypt and dissect
179 encrypted network captures. Enable this carefully.
182 config CIFS_DFS_UPCALL
183 bool "DFS feature support"
184 depends on CIFS && KEYS
187 Distributed File System (DFS) support is used to access shares
188 transparently in an enterprise name space, even if the share
189 moves to a different server. This feature also enables
190 an upcall mechanism for CIFS which contacts userspace helper
191 utilities to provide server name resolution (host names to
192 IP addresses) which is needed for implicit mounts of DFS junction
193 points. If unsure, say Y.
195 config CIFS_NFSD_EXPORT
196 bool "Allow nfsd to export CIFS file system"
197 depends on CIFS && BROKEN
199 Allows NFS server to export a CIFS mounted share (nfsd over cifs)
201 config CIFS_SMB_DIRECT
202 bool "SMB Direct support (Experimental)"
203 depends on CIFS=m && INFINIBAND && INFINIBAND_ADDR_TRANS || CIFS=y && INFINIBAND=y && INFINIBAND_ADDR_TRANS=y
205 Enables SMB Direct experimental support for SMB 3.0, 3.02 and 3.1.1.
206 SMB Direct allows transferring SMB packets over RDMA. If unsure,
210 bool "Provide CIFS client caching support"
211 depends on CIFS=m && FSCACHE || CIFS=y && FSCACHE=y
213 Makes CIFS FS-Cache capable. Say Y here if you want your CIFS data
214 to be cached locally on disk through the general filesystem cache
215 manager. If unsure, say N.