| # SPDX-License-Identifier: GPL-2.0-only |
| config CIFS |
| tristate "SMB3 and CIFS support (advanced network filesystem)" |
| depends on INET |
| select NLS |
| select CRYPTO |
| select CRYPTO_MD4 |
| select CRYPTO_MD5 |
| select CRYPTO_SHA256 |
| select CRYPTO_SHA512 |
| select CRYPTO_CMAC |
| select CRYPTO_HMAC |
| select CRYPTO_LIB_ARC4 |
| select CRYPTO_AEAD2 |
| select CRYPTO_CCM |
| select CRYPTO_GCM |
| select CRYPTO_ECB |
| select CRYPTO_AES |
| select CRYPTO_LIB_DES |
| select KEYS |
| help |
| This is the client VFS module for the SMB3 family of NAS protocols, |
| (including support for the most recent, most secure dialect SMB3.1.1) |
| as well as for earlier dialects such as SMB2.1, SMB2 and the older |
| Common Internet File System (CIFS) protocol. CIFS was the successor |
| to the original dialect, the Server Message Block (SMB) protocol, the |
| native file sharing mechanism for most early PC operating systems. |
| |
| The SMB3 protocol is supported by most modern operating systems |
| and NAS appliances (e.g. Samba, Windows 10, Windows Server 2016, |
| MacOS) and even in the cloud (e.g. Microsoft Azure). |
| The older CIFS protocol was included in Windows NT4, 2000 and XP (and |
| later) as well by Samba (which provides excellent CIFS and SMB3 |
| server support for Linux and many other operating systems). Use of |
| dialects older than SMB2.1 is often discouraged on public networks. |
| This module also provides limited support for OS/2 and Windows ME |
| and similar very old servers. |
| |
| This module provides an advanced network file system client |
| for mounting to SMB3 (and CIFS) compliant servers. It includes |
| support for DFS (hierarchical name space), secure per-user |
| session establishment via Kerberos or NTLM or NTLMv2, RDMA |
| (smbdirect), advanced security features, per-share encryption, |
| directory leases, safe distributed caching (oplock), optional packet |
| signing, Unicode and other internationalization improvements. |
| |
| In general, the default dialects, SMB3 and later, enable better |
| performance, security and features, than would be possible with CIFS. |
| Note that when mounting to Samba, due to the CIFS POSIX extensions, |
| CIFS mounts can provide slightly better POSIX compatibility |
| than SMB3 mounts. SMB2/SMB3 mount options are also |
| slightly simpler (compared to CIFS) due to protocol improvements. |
| |
| If you need to mount to Samba, Azure, Macs or Windows from this machine, say Y. |
| |
| config CIFS_STATS2 |
| bool "Extended statistics" |
| depends on CIFS |
| help |
| Enabling this option will allow more detailed statistics on SMB |
| request timing to be displayed in /proc/fs/cifs/DebugData and also |
| allow optional logging of slow responses to dmesg (depending on the |
| value of /proc/fs/cifs/cifsFYI, see fs/cifs/README for more details). |
| These additional statistics may have a minor effect on performance |
| and memory utilization. |
| |
| Unless you are a developer or are doing network performance analysis |
| or tuning, say N. |
| |
| config CIFS_ALLOW_INSECURE_LEGACY |
| bool "Support legacy servers which use less secure dialects" |
| depends on CIFS |
| default y |
| help |
| Modern dialects, SMB2.1 and later (including SMB3 and 3.1.1), have |
| additional security features, including protection against |
| man-in-the-middle attacks and stronger crypto hashes, so the use |
| of legacy dialects (SMB1/CIFS and SMB2.0) is discouraged. |
| |
| Disabling this option prevents users from using vers=1.0 or vers=2.0 |
| on mounts with cifs.ko |
| |
| If unsure, say Y. |
| |
| config CIFS_WEAK_PW_HASH |
| bool "Support legacy servers which use weaker LANMAN security" |
| depends on CIFS && CIFS_ALLOW_INSECURE_LEGACY |
| help |
| Modern CIFS servers including Samba and most Windows versions |
| (since 1997) support stronger NTLM (and even NTLMv2 and Kerberos) |
| security mechanisms. These hash the password more securely |
| than the mechanisms used in the older LANMAN version of the |
| SMB protocol but LANMAN based authentication is needed to |
| establish sessions with some old SMB servers. |
| |
| Enabling this option allows the cifs module to mount to older |
| LANMAN based servers such as OS/2 and Windows 95, but such |
| mounts may be less secure than mounts using NTLM or more recent |
| security mechanisms if you are on a public network. Unless you |
| have a need to access old SMB servers (and are on a private |
| network) you probably want to say N. Even if this support |
| is enabled in the kernel build, LANMAN authentication will not be |
| used automatically. At runtime LANMAN mounts are disabled but |
| can be set to required (or optional) either in |
| /proc/fs/cifs (see fs/cifs/README for more detail) or via an |
| option on the mount command. This support is disabled by |
| default in order to reduce the possibility of a downgrade |
| attack. |
| |
| If unsure, say N. |
| |
| config CIFS_UPCALL |
| bool "Kerberos/SPNEGO advanced session setup" |
| depends on CIFS |
| select DNS_RESOLVER |
| help |
| Enables an upcall mechanism for CIFS which accesses userspace helper |
| utilities to provide SPNEGO packaged (RFC 4178) Kerberos tickets |
| which are needed to mount to certain secure servers (for which more |
| secure Kerberos authentication is required). If unsure, say Y. |
| |
| config CIFS_XATTR |
| bool "CIFS extended attributes" |
| depends on CIFS |
| help |
| Extended attributes are name:value pairs associated with inodes by |
| the kernel or by users (see the attr(5) manual page for details). |
| CIFS maps the name of extended attributes beginning with the user |
| namespace prefix to SMB/CIFS EAs. EAs are stored on Windows |
| servers without the user namespace prefix, but their names are |
| seen by Linux cifs clients prefaced by the user namespace prefix. |
| The system namespace (used by some filesystems to store ACLs) is |
| not supported at this time. |
| |
| If unsure, say Y. |
| |
| config CIFS_POSIX |
| bool "CIFS POSIX Extensions" |
| depends on CIFS && CIFS_ALLOW_INSECURE_LEGACY && CIFS_XATTR |
| help |
| Enabling this option will cause the cifs client to attempt to |
| negotiate a newer dialect with servers, such as Samba 3.0.5 |
| or later, that optionally can handle more POSIX like (rather |
| than Windows like) file behavior. It also enables |
| support for POSIX ACLs (getfacl and setfacl) to servers |
| (such as Samba 3.10 and later) which can negotiate |
| CIFS POSIX ACL support. If unsure, say N. |
| |
| config CIFS_DEBUG |
| bool "Enable CIFS debugging routines" |
| default y |
| depends on CIFS |
| help |
| Enabling this option adds helpful debugging messages to |
| the cifs code which increases the size of the cifs module. |
| If unsure, say Y. |
| |
| config CIFS_DEBUG2 |
| bool "Enable additional CIFS debugging routines" |
| depends on CIFS_DEBUG |
| help |
| Enabling this option adds a few more debugging routines |
| to the cifs code which slightly increases the size of |
| the cifs module and can cause additional logging of debug |
| messages in some error paths, slowing performance. This |
| option can be turned off unless you are debugging |
| cifs problems. If unsure, say N. |
| |
| config CIFS_DEBUG_DUMP_KEYS |
| bool "Dump encryption keys for offline decryption (Unsafe)" |
| depends on CIFS_DEBUG |
| help |
| Enabling this will dump the encryption and decryption keys |
| used to communicate on an encrypted share connection on the |
| console. This allows Wireshark to decrypt and dissect |
| encrypted network captures. Enable this carefully. |
| If unsure, say N. |
| |
| config CIFS_DFS_UPCALL |
| bool "DFS feature support" |
| depends on CIFS |
| select DNS_RESOLVER |
| help |
| Distributed File System (DFS) support is used to access shares |
| transparently in an enterprise name space, even if the share |
| moves to a different server. This feature also enables |
| an upcall mechanism for CIFS which contacts userspace helper |
| utilities to provide server name resolution (host names to |
| IP addresses) which is needed in order to reconnect to |
| servers if their addresses change or for implicit mounts of |
| DFS junction points. If unsure, say Y. |
| |
| config CIFS_NFSD_EXPORT |
| bool "Allow nfsd to export CIFS file system" |
| depends on CIFS && BROKEN |
| help |
| Allows NFS server to export a CIFS mounted share (nfsd over cifs) |
| |
| config CIFS_SMB_DIRECT |
| bool "SMB Direct support" |
| depends on CIFS=m && INFINIBAND && INFINIBAND_ADDR_TRANS || CIFS=y && INFINIBAND=y && INFINIBAND_ADDR_TRANS=y |
| help |
| Enables SMB Direct support for SMB 3.0, 3.02 and 3.1.1. |
| SMB Direct allows transferring SMB packets over RDMA. If unsure, |
| say N. |
| |
| config CIFS_FSCACHE |
| bool "Provide CIFS client caching support" |
| depends on CIFS=m && FSCACHE || CIFS=y && FSCACHE=y |
| help |
| Makes CIFS FS-Cache capable. Say Y here if you want your CIFS data |
| to be cached locally on disk through the general filesystem cache |
| manager. If unsure, say N. |
| |
| config CIFS_ROOT |
| bool "SMB root file system (Experimental)" |
| depends on CIFS=y && IP_PNP |
| help |
| Enables root file system support over SMB protocol. |
| |
| Most people say N here. |
