1 # SPDX-License-Identifier: GPL-2.0-only 2 config 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 56 config 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 70 config 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 85 config 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 94 config 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. 108 109 config 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. 120 121 config 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. 129 130 config 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. 140 141 config 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. 150 151 config 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. 163 164 config 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. 174 175 config 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) 180 181 if CIFS 182 183 config 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. 190 191 config 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. 198 199 config 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. 206 207 config 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. 220 221 endif 222