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 NETFS_SUPPORT
6	select NLS
7	select NLS_UCS2_UTILS
8	select CRYPTO
9	select CRYPTO_MD5
10	select CRYPTO_SHA256
11	select CRYPTO_SHA512
12	select CRYPTO_CMAC
13	select CRYPTO_HMAC
14	select CRYPTO_AEAD2
15	select CRYPTO_CCM
16	select CRYPTO_GCM
17	select CRYPTO_ECB
18	select CRYPTO_AES
19	select KEYS
20	select DNS_RESOLVER
21	select ASN1
22	select OID_REGISTRY
23	select NETFS_SUPPORT
24	help
25	  This is the client VFS module for the SMB3 family of network file
26	  protocols (including the most recent, most secure dialect SMB3.1.1).
27	  This module also includes support for earlier dialects such as
28	  SMB2.1, SMB2 and even the old Common Internet File System (CIFS)
29	  protocol.  CIFS was the successor to the original network filesystem
30	  protocol, Server Message Block (SMB ie SMB1), the native file sharing
31	  mechanism for most early PC operating systems.
32
33	  The SMB3.1.1 protocol is supported by most modern operating systems
34	  and NAS appliances (e.g. Samba, Windows 11, Windows Server 2022,
35	  MacOS) and even in the cloud (e.g. Microsoft Azure) and also by the
36	  Linux kernel server, ksmbd.  Support for the older CIFS protocol was
37	  included in Windows NT4, 2000 and XP (and later). Use of dialects
38	  older than SMB2.1 is often discouraged on public networks.
39	  This module also provides limited support for OS/2 and Windows ME
40	  and similar very old servers.
41
42	  This module provides an advanced network file system client for
43	  mounting to SMB3 (and CIFS) compliant servers.  It includes support
44	  for DFS (hierarchical name space), secure per-user session
45	  establishment via Kerberos or NTLMv2, RDMA (smbdirect), advanced
46	  security features, per-share encryption, packet-signing, snapshots,
47	  directory leases, safe distributed caching (leases), multichannel,
48	  Unicode and other internationalization improvements.
49
50	  In general, the default dialects, SMB3 and later, enable better
51	  performance, security and features, than would be possible with CIFS.
52
53	  If you need to mount to Samba, Azure, ksmbd, Macs or Windows from this
54	  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 feature of the older cifs dialect with servers, such as
115	  Samba 3.0.5 or later, that optionally can handle more POSIX like
116	  (rather than Windows like) file behavior.  It also enables support
117	  for POSIX ACLs (getfacl and setfacl) to servers (such as Samba 3.10
118	  and later) which can negotiate CIFS POSIX ACL support.  This config
119	  option is not needed when mounting with SMB3.1.1. 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
181if CIFS
182
183config CIFS_SMB_DIRECT
184	bool "SMB Direct support"
185	depends on CIFS=m && INFINIBAND && INFINIBAND_ADDR_TRANS || CIFS=y && INFINIBAND=y && INFINIBAND_ADDR_TRANS=y
186	help
187	  Enables SMB Direct support for SMB 3.0, 3.02 and 3.1.1.
188	  SMB Direct allows transferring SMB packets over RDMA. If unsure,
189	  say Y.
190
191config CIFS_FSCACHE
192	bool "Provide CIFS client caching support"
193	depends on CIFS=m && FSCACHE || CIFS=y && FSCACHE=y
194	help
195	  Makes CIFS FS-Cache capable. Say Y here if you want your CIFS data
196	  to be cached locally on disk through the general filesystem cache
197	  manager. If unsure, say N.
198
199config CIFS_ROOT
200	bool "SMB root file system (Experimental)"
201	depends on CIFS=y && IP_PNP
202	help
203	  Enables root file system support over SMB protocol.
204
205	  Most people say N here.
206
207config CIFS_COMPRESSION
208	bool "SMB message compression (Experimental)"
209	depends on CIFS
210	default n
211	help
212	  Enables over-the-wire message compression for SMB 3.1.1
213	  mounts when negotiated with the server.
214
215	  Only write requests with data size >= PAGE_SIZE will be
216	  compressed to avoid wasting resources.
217
218	  Say Y here if you want SMB traffic to be compressed.
219	  If unsure, say N.
220
221endif
222