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.