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1# SPDX-License-Identifier: GPL-2.0-only
2config CIFS
3 tristate "SMB3 and CIFS support (advanced network filesystem)"
4 depends on INET
5 select NLS
6 select CRYPTO
7 select CRYPTO_MD5
8 select CRYPTO_SHA256
9 select CRYPTO_SHA512
10 select CRYPTO_CMAC
11 select CRYPTO_HMAC
12 select CRYPTO_AEAD2
13 select CRYPTO_CCM
14 select CRYPTO_GCM
15 select CRYPTO_ECB
16 select CRYPTO_AES
17 select KEYS
18 select DNS_RESOLVER
19 select ASN1
20 select OID_REGISTRY
21 help
22 This is the client VFS module for the SMB3 family of NAS protocols,
23 (including support for the most recent, most secure dialect SMB3.1.1)
24 as well as for earlier dialects such as SMB2.1, SMB2 and the older
25 Common Internet File System (CIFS) protocol. CIFS was the successor
26 to the original dialect, the Server Message Block (SMB) protocol, the
27 native file sharing mechanism for most early PC operating systems.
28
29 The SMB3 protocol is supported by most modern operating systems
30 and NAS appliances (e.g. Samba, Windows 10, Windows Server 2016,
31 MacOS) and even in the cloud (e.g. Microsoft Azure).
32 The older CIFS protocol was included in Windows NT4, 2000 and XP (and
33 later) as well by Samba (which provides excellent CIFS and SMB3
34 server support for Linux and many other operating systems). Use of
35 dialects older than SMB2.1 is often discouraged on public networks.
36 This module also provides limited support for OS/2 and Windows ME
37 and similar very old servers.
38
39 This module provides an advanced network file system client
40 for mounting to SMB3 (and CIFS) compliant servers. It includes
41 support for DFS (hierarchical name space), secure per-user
42 session establishment via Kerberos or NTLM or NTLMv2, RDMA
43 (smbdirect), advanced security features, per-share encryption,
44 directory leases, safe distributed caching (oplock), optional packet
45 signing, Unicode and other internationalization improvements.
46
47 In general, the default dialects, SMB3 and later, enable better
48 performance, security and features, than would be possible with CIFS.
49 Note that when mounting to Samba, due to the CIFS POSIX extensions,
50 CIFS mounts can provide slightly better POSIX compatibility
51 than SMB3 mounts. SMB2/SMB3 mount options are also
52 slightly simpler (compared to CIFS) due to protocol improvements.
53
54 If you need to mount to Samba, Azure, Macs or Windows from this machine, say Y.
55
56config CIFS_STATS2
57 bool "Extended statistics"
58 depends on CIFS
59 default y
60 help
61 Enabling this option will allow more detailed statistics on SMB
62 request timing to be displayed in /proc/fs/cifs/DebugData and also
63 allow optional logging of slow responses to dmesg (depending on the
64 value of /proc/fs/cifs/cifsFYI). See Documentation/admin-guide/cifs/usage.rst
65 for more details. These additional statistics may have a minor effect
66 on performance and memory utilization.
67
68 If unsure, say Y.
69
70config CIFS_ALLOW_INSECURE_LEGACY
71 bool "Support legacy servers which use less secure dialects"
72 depends on CIFS
73 default y
74 help
75 Modern dialects, SMB2.1 and later (including SMB3 and 3.1.1), have
76 additional security features, including protection against
77 man-in-the-middle attacks and stronger crypto hashes, so the use
78 of legacy dialects (SMB1/CIFS and SMB2.0) is discouraged.
79
80 Disabling this option prevents users from using vers=1.0 or vers=2.0
81 on mounts with cifs.ko
82
83 If unsure, say Y.
84
85config CIFS_UPCALL
86 bool "Kerberos/SPNEGO advanced session setup"
87 depends on CIFS
88 help
89 Enables an upcall mechanism for CIFS which accesses userspace helper
90 utilities to provide SPNEGO packaged (RFC 4178) Kerberos tickets
91 which are needed to mount to certain secure servers (for which more
92 secure Kerberos authentication is required). If unsure, say Y.
93
94config CIFS_XATTR
95 bool "CIFS extended attributes"
96 depends on CIFS
97 help
98 Extended attributes are name:value pairs associated with inodes by
99 the kernel or by users (see the attr(5) manual page for details).
100 CIFS maps the name of extended attributes beginning with the user
101 namespace prefix to SMB/CIFS EAs. EAs are stored on Windows
102 servers without the user namespace prefix, but their names are
103 seen by Linux cifs clients prefaced by the user namespace prefix.
104 The system namespace (used by some filesystems to store ACLs) is
105 not supported at this time.
106
107 If unsure, say Y.
108
109config CIFS_POSIX
110 bool "CIFS POSIX Extensions"
111 depends on CIFS && CIFS_ALLOW_INSECURE_LEGACY && CIFS_XATTR
112 help
113 Enabling this option will cause the cifs client to attempt to
114 negotiate a newer dialect with servers, such as Samba 3.0.5
115 or later, that optionally can handle more POSIX like (rather
116 than Windows like) file behavior. It also enables
117 support for POSIX ACLs (getfacl and setfacl) to servers
118 (such as Samba 3.10 and later) which can negotiate
119 CIFS POSIX ACL support. If unsure, say N.
120
121config CIFS_DEBUG
122 bool "Enable CIFS debugging routines"
123 default y
124 depends on CIFS
125 help
126 Enabling this option adds helpful debugging messages to
127 the cifs code which increases the size of the cifs module.
128 If unsure, say Y.
129
130config CIFS_DEBUG2
131 bool "Enable additional CIFS debugging routines"
132 depends on CIFS_DEBUG
133 help
134 Enabling this option adds a few more debugging routines
135 to the cifs code which slightly increases the size of
136 the cifs module and can cause additional logging of debug
137 messages in some error paths, slowing performance. This
138 option can be turned off unless you are debugging
139 cifs problems. If unsure, say N.
140
141config CIFS_DEBUG_DUMP_KEYS
142 bool "Dump encryption keys for offline decryption (Unsafe)"
143 depends on CIFS_DEBUG
144 help
145 Enabling this will dump the encryption and decryption keys
146 used to communicate on an encrypted share connection on the
147 console. This allows Wireshark to decrypt and dissect
148 encrypted network captures. Enable this carefully.
149 If unsure, say N.
150
151config CIFS_DFS_UPCALL
152 bool "DFS feature support"
153 depends on CIFS
154 help
155 Distributed File System (DFS) support is used to access shares
156 transparently in an enterprise name space, even if the share
157 moves to a different server. This feature also enables
158 an upcall mechanism for CIFS which contacts userspace helper
159 utilities to provide server name resolution (host names to
160 IP addresses) which is needed in order to reconnect to
161 servers if their addresses change or for implicit mounts of
162 DFS junction points. If unsure, say Y.
163
164config CIFS_SWN_UPCALL
165 bool "SWN feature support"
166 depends on CIFS
167 help
168 The Service Witness Protocol (SWN) is used to get notifications
169 from a highly available server of resource state changes. This
170 feature enables an upcall mechanism for CIFS which contacts a
171 userspace daemon to establish the DCE/RPC connection to retrieve
172 the cluster available interfaces and resource change notifications.
173 If unsure, say Y.
174
175config CIFS_NFSD_EXPORT
176 bool "Allow nfsd to export CIFS file system"
177 depends on CIFS && BROKEN
178 help
179 Allows NFS server to export a CIFS mounted share (nfsd over cifs)
180
181config 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
184 help
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,
187 say Y.
188
189config CIFS_FSCACHE
190 bool "Provide CIFS client caching support"
191 depends on CIFS=m && FSCACHE || CIFS=y && FSCACHE=y
192 help
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.
196
197config CIFS_ROOT
198 bool "SMB root file system (Experimental)"
199 depends on CIFS=y && IP_PNP
200 help
201 Enables root file system support over SMB protocol.
202
203 Most people say N here.
1config CIFS
2 tristate "CIFS support (advanced network filesystem, SMBFS successor)"
3 depends on INET
4 select NLS
5 select CRYPTO
6 select CRYPTO_MD4
7 select CRYPTO_MD5
8 select CRYPTO_HMAC
9 select CRYPTO_ARC4
10 select CRYPTO_ECB
11 select CRYPTO_DES
12 select CRYPTO_SHA256
13 select CRYPTO_CMAC
14 help
15 This is the client VFS module for the Common Internet File System
16 (CIFS) protocol which is the successor to the Server Message Block
17 (SMB) protocol, the native file sharing mechanism for most early
18 PC operating systems. The CIFS protocol is fully supported by
19 file servers such as Windows 2000 (including Windows 2003, Windows 2008,
20 NT 4 and Windows XP) as well by Samba (which provides excellent CIFS
21 server support for Linux and many other operating systems). Limited
22 support for OS/2 and Windows ME and similar servers is provided as
23 well.
24
25 The module also provides optional support for the followon
26 protocols for CIFS including SMB3, which enables
27 useful performance and security features (see the description
28 of CONFIG_CIFS_SMB2).
29
30 The cifs module provides an advanced network file system
31 client for mounting to CIFS compliant servers. It includes
32 support for DFS (hierarchical name space), secure per-user
33 session establishment via Kerberos or NTLM or NTLMv2,
34 safe distributed caching (oplock), optional packet
35 signing, Unicode and other internationalization improvements.
36 If you need to mount to Samba or Windows from this machine, say Y.
37
38config CIFS_STATS
39 bool "CIFS statistics"
40 depends on CIFS
41 help
42 Enabling this option will cause statistics for each server share
43 mounted by the cifs client to be displayed in /proc/fs/cifs/Stats
44
45config CIFS_STATS2
46 bool "Extended statistics"
47 depends on CIFS_STATS
48 help
49 Enabling this option will allow more detailed statistics on SMB
50 request timing to be displayed in /proc/fs/cifs/DebugData and also
51 allow optional logging of slow responses to dmesg (depending on the
52 value of /proc/fs/cifs/cifsFYI, see fs/cifs/README for more details).
53 These additional statistics may have a minor effect on performance
54 and memory utilization.
55
56 Unless you are a developer or are doing network performance analysis
57 or tuning, say N.
58
59config CIFS_WEAK_PW_HASH
60 bool "Support legacy servers which use weaker LANMAN security"
61 depends on CIFS
62 help
63 Modern CIFS servers including Samba and most Windows versions
64 (since 1997) support stronger NTLM (and even NTLMv2 and Kerberos)
65 security mechanisms. These hash the password more securely
66 than the mechanisms used in the older LANMAN version of the
67 SMB protocol but LANMAN based authentication is needed to
68 establish sessions with some old SMB servers.
69
70 Enabling this option allows the cifs module to mount to older
71 LANMAN based servers such as OS/2 and Windows 95, but such
72 mounts may be less secure than mounts using NTLM or more recent
73 security mechanisms if you are on a public network. Unless you
74 have a need to access old SMB servers (and are on a private
75 network) you probably want to say N. Even if this support
76 is enabled in the kernel build, LANMAN authentication will not be
77 used automatically. At runtime LANMAN mounts are disabled but
78 can be set to required (or optional) either in
79 /proc/fs/cifs (see fs/cifs/README for more detail) or via an
80 option on the mount command. This support is disabled by
81 default in order to reduce the possibility of a downgrade
82 attack.
83
84 If unsure, say N.
85
86config CIFS_UPCALL
87 bool "Kerberos/SPNEGO advanced session setup"
88 depends on CIFS && KEYS
89 select DNS_RESOLVER
90 help
91 Enables an upcall mechanism for CIFS which accesses userspace helper
92 utilities to provide SPNEGO packaged (RFC 4178) Kerberos tickets
93 which are needed to mount to certain secure servers (for which more
94 secure Kerberos authentication is required). If unsure, say N.
95
96config CIFS_XATTR
97 bool "CIFS extended attributes"
98 depends on CIFS
99 help
100 Extended attributes are name:value pairs associated with inodes by
101 the kernel or by users (see the attr(5) manual page, or visit
102 <http://acl.bestbits.at/> for details). CIFS maps the name of
103 extended attributes beginning with the user namespace prefix
104 to SMB/CIFS EAs. EAs are stored on Windows servers without the
105 user namespace prefix, but their names are seen by Linux cifs clients
106 prefaced by the user namespace prefix. The system namespace
107 (used by some filesystems to store ACLs) is not supported at
108 this time.
109
110 If unsure, say N.
111
112config CIFS_POSIX
113 bool "CIFS POSIX Extensions"
114 depends on CIFS_XATTR
115 help
116 Enabling this option will cause the cifs client to attempt to
117 negotiate a newer dialect with servers, such as Samba 3.0.5
118 or later, that optionally can handle more POSIX like (rather
119 than Windows like) file behavior. It also enables
120 support for POSIX ACLs (getfacl and setfacl) to servers
121 (such as Samba 3.10 and later) which can negotiate
122 CIFS POSIX ACL support. If unsure, say N.
123
124config CIFS_ACL
125 bool "Provide CIFS ACL support"
126 depends on CIFS_XATTR && KEYS
127 help
128 Allows fetching CIFS/NTFS ACL from the server. The DACL blob
129 is handed over to the application/caller. See the man
130 page for getcifsacl for more information.
131
132config CIFS_DEBUG
133 bool "Enable CIFS debugging routines"
134 default y
135 depends on CIFS
136 help
137 Enabling this option adds helpful debugging messages to
138 the cifs code which increases the size of the cifs module.
139 If unsure, say Y.
140config CIFS_DEBUG2
141 bool "Enable additional CIFS debugging routines"
142 depends on CIFS_DEBUG
143 help
144 Enabling this option adds a few more debugging routines
145 to the cifs code which slightly increases the size of
146 the cifs module and can cause additional logging of debug
147 messages in some error paths, slowing performance. This
148 option can be turned off unless you are debugging
149 cifs problems. If unsure, say N.
150
151config CIFS_DFS_UPCALL
152 bool "DFS feature support"
153 depends on CIFS && KEYS
154 select DNS_RESOLVER
155 help
156 Distributed File System (DFS) support is used to access shares
157 transparently in an enterprise name space, even if the share
158 moves to a different server. This feature also enables
159 an upcall mechanism for CIFS which contacts userspace helper
160 utilities to provide server name resolution (host names to
161 IP addresses) which is needed for implicit mounts of DFS junction
162 points. If unsure, say N.
163
164config CIFS_NFSD_EXPORT
165 bool "Allow nfsd to export CIFS file system"
166 depends on CIFS && BROKEN
167 help
168 Allows NFS server to export a CIFS mounted share (nfsd over cifs)
169
170config CIFS_SMB2
171 bool "SMB2 and SMB3 network file system support"
172 depends on CIFS && INET
173 select NLS
174 select KEYS
175 select FSCACHE
176 select DNS_RESOLVER
177
178 help
179 This enables support for the Server Message Block version 2
180 family of protocols, including SMB3. SMB3 support is
181 enabled on mount by specifying "vers=3.0" in the mount
182 options. These protocols are the successors to the popular
183 CIFS and SMB network file sharing protocols. SMB3 is the
184 native file sharing mechanism for the more recent
185 versions of Windows (Windows 8 and Windows 2012 and
186 later) and Samba server and many others support SMB3 well.
187 In general SMB3 enables better performance, security
188 and features, than would be possible with CIFS (Note that
189 when mounting to Samba, due to the CIFS POSIX extensions,
190 CIFS mounts can provide slightly better POSIX compatibility
191 than SMB3 mounts do though). Note that SMB2/SMB3 mount
192 options are also slightly simpler (compared to CIFS) due
193 to protocol improvements.
194
195config CIFS_SMB311
196 bool "SMB3.1.1 network file system support (Experimental)"
197 depends on CIFS_SMB2 && INET
198
199 help
200 This enables experimental support for the newest, SMB3.1.1, dialect.
201 This dialect includes improved security negotiation features.
202 If unsure, say N
203
204config CIFS_FSCACHE
205 bool "Provide CIFS client caching support"
206 depends on CIFS=m && FSCACHE || CIFS=y && FSCACHE=y
207 help
208 Makes CIFS FS-Cache capable. Say Y here if you want your CIFS data
209 to be cached locally on disk through the general filesystem cache
210 manager. If unsure, say N.
211