fs/cifs/Kconfig

   1 config CIFS
   2         tristate "SMB3 and CIFS support (advanced network filesystem)"
   3         depends on INET
   4         select NLS
   5         select CRYPTO
   6         select CRYPTO_MD4
   7         select CRYPTO_MD5
   8         select CRYPTO_SHA256
   9         select CRYPTO_SHA512
  10         select CRYPTO_CMAC
  11         select CRYPTO_HMAC
  12         select CRYPTO_ARC4
  13         select CRYPTO_AEAD2
  14         select CRYPTO_CCM
  15         select CRYPTO_ECB
  16         select CRYPTO_AES
  17         select CRYPTO_DES
  18         help
  19           This is the client VFS module for the SMB3 family of NAS protocols,
  20           (including support for the most recent, most secure dialect SMB3.1.1)
  21           as well as for earlier dialects such as SMB2.1, SMB2 and the older
  22           Common Internet File System (CIFS) protocol.  CIFS was the successor
  23           to the original dialect, the Server Message Block (SMB) protocol, the
  24           native file sharing mechanism for most early PC operating systems.
  25
  26           The SMB3 protocol is supported by most modern operating systems
  27           and NAS appliances (e.g. Samba, Windows 10, Windows Server 2016,
  28           MacOS) and even in the cloud (e.g. Microsoft Azure).
  29           The older CIFS protocol was included in Windows NT4, 2000 and XP (and
  30           later) as well by Samba (which provides excellent CIFS and SMB3
  31           server support for Linux and many other operating systems). Use of
  32           dialects older than SMB2.1 is often discouraged on public networks.
  33           This module also provides limited support for OS/2 and Windows ME
  34           and similar very old servers.
  35
  36           This module provides an advanced network file system client
  37           for mounting to SMB3 (and CIFS) compliant servers.  It includes
  38           support for DFS (hierarchical name space), secure per-user
  39           session establishment via Kerberos or NTLM or NTLMv2, RDMA
  40           (smbdirect), advanced security features, per-share encryption,
  41           directory leases, safe distributed caching (oplock), optional packet
  42           signing, Unicode and other internationalization improvements.
  43
  44           In general, the default dialects, SMB3 and later, enable better
  45           performance, security and features, than would be possible with CIFS.
  46           Note that when mounting to Samba, due to the CIFS POSIX extensions,
  47           CIFS mounts can provide slightly better POSIX compatibility
  48           than SMB3 mounts. SMB2/SMB3 mount options are also
  49           slightly simpler (compared to CIFS) due to protocol improvements.
  50
  51           If you need to mount to Samba, Azure, Macs or Windows from this machine, say Y.
  52
  53 config CIFS_STATS2
  54         bool "Extended statistics"
  55         depends on CIFS
  56         help
  57           Enabling this option will allow more detailed statistics on SMB
  58           request timing to be displayed in /proc/fs/cifs/DebugData and also
  59           allow optional logging of slow responses to dmesg (depending on the
  60           value of /proc/fs/cifs/cifsFYI, see fs/cifs/README for more details).
  61           These additional statistics may have a minor effect on performance
  62           and memory utilization.
  63
  64           Unless you are a developer or are doing network performance analysis
  65           or tuning, say N.
  66
  67 config CIFS_ALLOW_INSECURE_LEGACY
  68         bool "Support legacy servers which use less secure dialects"
  69         depends on CIFS
  70         default y
  71         help
  72           Modern dialects, SMB2.1 and later (including SMB3 and 3.1.1), have
  73           additional security features, including protection against
  74           man-in-the-middle attacks and stronger crypto hashes, so the use
  75           of legacy dialects (SMB1/CIFS and SMB2.0) is discouraged.
  76
  77           Disabling this option prevents users from using vers=1.0 or vers=2.0
  78           on mounts with cifs.ko
  79
  80           If unsure, say Y.
  81
  82 config CIFS_WEAK_PW_HASH
  83         bool "Support legacy servers which use weaker LANMAN security"
  84         depends on CIFS && CIFS_ALLOW_INSECURE_LEGACY
  85         help
  86           Modern CIFS servers including Samba and most Windows versions
  87           (since 1997) support stronger NTLM (and even NTLMv2 and Kerberos)
  88           security mechanisms. These hash the password more securely
  89           than the mechanisms used in the older LANMAN version of the
  90           SMB protocol but LANMAN based authentication is needed to
  91           establish sessions with some old SMB servers.
  92
  93           Enabling this option allows the cifs module to mount to older
  94           LANMAN based servers such as OS/2 and Windows 95, but such
  95           mounts may be less secure than mounts using NTLM or more recent
  96           security mechanisms if you are on a public network.  Unless you
  97           have a need to access old SMB servers (and are on a private
  98           network) you probably want to say N.  Even if this support
  99           is enabled in the kernel build, LANMAN authentication will not be
 100           used automatically. At runtime LANMAN mounts are disabled but
 101           can be set to required (or optional) either in
 102           /proc/fs/cifs (see fs/cifs/README for more detail) or via an
 103           option on the mount command. This support is disabled by
 104           default in order to reduce the possibility of a downgrade
 105           attack.
 106
 107           If unsure, say N.
 108
 109 config CIFS_UPCALL
 110         bool "Kerberos/SPNEGO advanced session setup"
 111         depends on CIFS && KEYS
 112         select DNS_RESOLVER
 113         help
 114           Enables an upcall mechanism for CIFS which accesses userspace helper
 115           utilities to provide SPNEGO packaged (RFC 4178) Kerberos tickets
 116           which are needed to mount to certain secure servers (for which more
 117           secure Kerberos authentication is required). If unsure, say Y.
 118
 119 config CIFS_XATTR
 120         bool "CIFS extended attributes"
 121         depends on CIFS
 122         help
 123           Extended attributes are name:value pairs associated with inodes by
 124           the kernel or by users (see the attr(5) manual page for details).
 125           CIFS maps the name of extended attributes beginning with the user
 126           namespace prefix to SMB/CIFS EAs.  EAs are stored on Windows
 127           servers without the user namespace prefix, but their names are
 128           seen by Linux cifs clients prefaced by the user namespace prefix.
 129           The system namespace (used by some filesystems to store ACLs) is
 130           not supported at this time.
 131
 132           If unsure, say Y.
 133
 134 config CIFS_POSIX
 135         bool "CIFS POSIX Extensions"
 136         depends on CIFS_XATTR
 137         help
 138           Enabling this option will cause the cifs client to attempt to
 139           negotiate a newer dialect with servers, such as Samba 3.0.5
 140           or later, that optionally can handle more POSIX like (rather
 141           than Windows like) file behavior.  It also enables
 142           support for POSIX ACLs (getfacl and setfacl) to servers
 143           (such as Samba 3.10 and later) which can negotiate
 144           CIFS POSIX ACL support.  If unsure, say N.
 145
 146 config CIFS_ACL
 147           bool "Provide CIFS ACL support"
 148           depends on CIFS_XATTR && KEYS
 149           help
 150             Allows fetching CIFS/NTFS ACL from the server.  The DACL blob
 151             is handed over to the application/caller.  See the man
 152             page for getcifsacl for more information.  If unsure, say Y.
 153
 154 config CIFS_DEBUG
 155         bool "Enable CIFS debugging routines"
 156         default y
 157         depends on CIFS
 158         help
 159            Enabling this option adds helpful debugging messages to
 160            the cifs code which increases the size of the cifs module.
 161            If unsure, say Y.
 162 config CIFS_DEBUG2
 163         bool "Enable additional CIFS debugging routines"
 164         depends on CIFS_DEBUG
 165         help
 166            Enabling this option adds a few more debugging routines
 167            to the cifs code which slightly increases the size of
 168            the cifs module and can cause additional logging of debug
 169            messages in some error paths, slowing performance. This
 170            option can be turned off unless you are debugging
 171            cifs problems.  If unsure, say N.
 172
 173 config CIFS_DEBUG_DUMP_KEYS
 174         bool "Dump encryption keys for offline decryption (Unsafe)"
 175         depends on CIFS_DEBUG
 176         help
 177            Enabling this will dump the encryption and decryption keys
 178            used to communicate on an encrypted share connection on the
 179            console. This allows Wireshark to decrypt and dissect
 180            encrypted network captures. Enable this carefully.
 181            If unsure, say N.
 182
 183 config CIFS_DFS_UPCALL
 184           bool "DFS feature support"
 185           depends on CIFS && KEYS
 186           select DNS_RESOLVER
 187           help
 188             Distributed File System (DFS) support is used to access shares
 189             transparently in an enterprise name space, even if the share
 190             moves to a different server.  This feature also enables
 191             an upcall mechanism for CIFS which contacts userspace helper
 192             utilities to provide server name resolution (host names to
 193             IP addresses) which is needed for implicit mounts of DFS junction
 194             points. If unsure, say Y.
 195
 196 config CIFS_NFSD_EXPORT
 197           bool "Allow nfsd to export CIFS file system"
 198           depends on CIFS && BROKEN
 199           help
 200            Allows NFS server to export a CIFS mounted share (nfsd over cifs)
 201
 202 config CIFS_SMB_DIRECT
 203         bool "SMB Direct support (Experimental)"
 204         depends on CIFS=m && INFINIBAND && INFINIBAND_ADDR_TRANS || CIFS=y && INFINIBAND=y && INFINIBAND_ADDR_TRANS=y
 205         help
 206           Enables SMB Direct experimental support for SMB 3.0, 3.02 and 3.1.1.
 207           SMB Direct allows transferring SMB packets over RDMA. If unsure,
 208           say N.
 209
 210 config CIFS_FSCACHE
 211           bool "Provide CIFS client caching support"
 212           depends on CIFS=m && FSCACHE || CIFS=y && FSCACHE=y
 213           help
 214             Makes CIFS FS-Cache capable. Say Y here if you want your CIFS data
 215             to be cached locally on disk through the general filesystem cache
 216             manager. If unsure, say N.
 217