It was designed to comply with the SNIA CIFS Technical Reference (which
supersedes the 1992 X/Open SMB Standard) as well as to perform best practice
practical interoperability with Windows 2000, Windows XP, Samba and equivalent
-servers.
+servers. This code was developed in participation with the Protocol Freedom
+Information Foundation.
+
+Please see
+ http://protocolfreedom.org/ and
+ http://samba.org/samba/PFIF/
+for more details.
+
For questions or bug reports please contact:
sfrench@samba.org (sfrench@us.ibm.com)
mount.
domain Set the SMB/CIFS workgroup name prepended to the
username during CIFS session establishment
- uid Set the default uid for inodes. For mounts to servers
+ forceuid Set the default uid for inodes to the uid
+ passed in on mount. For mounts to servers
which do support the CIFS Unix extensions, such as a
properly configured Samba server, the server provides
- the uid, gid and mode so this parameter should not be
+ the uid, gid and mode so this parameter should not be
specified unless the server and clients uid and gid
numbering differ. If the server and client are in the
same domain (e.g. running winbind or nss_ldap) and
of existing files will be the uid (gid) of the person
who executed the mount (root, except when mount.cifs
is configured setuid for user mounts) unless the "uid="
- (gid) mount option is specified. For the uid (gid) of newly
- created files and directories, ie files created since
- the last mount of the server share, the expected uid
- (gid) is cached as long as the inode remains in
- memory on the client. Also note that permission
+ (gid) mount option is specified. Also note that permission
checks (authorization checks) on accesses to a file occur
at the server, but there are cases in which an administrator
may want to restrict at the client as well. For those
(such as Windows), permissions can also be checked at the
client, and a crude form of client side permission checking
can be enabled by specifying file_mode and dir_mode on
- the client. Note that the mount.cifs helper must be
- at version 1.10 or higher to support specifying the uid
- (or gid) in non-numeric form.
+ the client. (default)
+ forcegid (similar to above but for the groupid instead of uid) (default)
+ noforceuid Fill in file owner information (uid) by requesting it from
+ the server if possible. With this option, the value given in
+ the uid= option (on mount) will only be used if the server
+ can not support returning uids on inodes.
+ noforcegid (similar to above but for the group owner, gid, instead of uid)
+ uid Set the default uid for inodes, and indicate to the
+ cifs kernel driver which local user mounted. If the server
+ supports the unix extensions the default uid is
+ not used to fill in the owner fields of inodes (files)
+ unless the "forceuid" parameter is specified.
gid Set the default gid for inodes (similar to above).
file_mode If CIFS Unix extensions are not supported by the server
this overrides the default mode for file inodes.
or the CIFS Unix Extensions equivalent and for those
this mount option will have no effect. Exporting cifs mounts
under nfsd requires this mount option on the cifs mount.
+ This is now the default if server supports the
+ required network operation.
noserverino Client generates inode numbers (rather than using the actual one
- from the server) by default.
+ from the server). These inode numbers will vary after
+ unmount or reboot which can confuse some applications,
+ but not all server filesystems support unique inode
+ numbers.
setuids If the CIFS Unix extensions are negotiated with the server
the client will attempt to set the effective uid and gid of
the local process on newly created files, directories, and
source name to use to represent the client netbios machine
name when doing the RFC1001 netbios session initialize.
direct Do not do inode data caching on files opened on this mount.
- This precludes mmaping files on this mount. In some cases
+ This precludes mmapping files on this mount. In some cases
with fast networks and little or no caching benefits on the
client (e.g. when the application is doing large sequential
reads bigger than page size without rereading the same data)
with cifs style mandatory byte range locks (and most
cifs servers do not yet support requesting advisory
byte range locks).
+ forcemandatorylock Even if the server supports posix (advisory) byte range
+ locking, send only mandatory lock requests. For some
+ (presumably rare) applications, originally coded for
+ DOS/Windows, which require Windows style mandatory byte range
+ locking, they may be able to take advantage of this option,
+ forcing the cifs client to only send mandatory locks
+ even if the cifs server would support posix advisory locks.
+ "forcemand" is accepted as a shorter form of this mount
+ option.
+ nostrictsync If this mount option is set, when an application does an
+ fsync call then the cifs client does not send an SMB Flush
+ to the server (to force the server to write all dirty data
+ for this file immediately to disk), although cifs still sends
+ all dirty (cached) file data to the server and waits for the
+ server to respond to the write. Since SMB Flush can be
+ very slow, and some servers may be reliable enough (to risk
+ delaying slightly flushing the data to disk on the server),
+ turning on this option may be useful to improve performance for
+ applications that fsync too much, at a small risk of server
+ crash. If this mount option is not set, by default cifs will
+ send an SMB flush request (and wait for a response) on every
+ fsync call.
+ nodfs Disable DFS (global name space support) even if the
+ server claims to support it. This can help work around
+ a problem with parsing of DFS paths with Samba server
+ versions 3.0.24 and 3.0.25.
remount remount the share (often used to change from ro to rw mounts
or vice versa)
cifsacl Report mode bits (e.g. on stat) based on the Windows ACL for
the file. (EXPERIMENTAL)
servern Specify the server 's netbios name (RFC1001 name) to use
- when attempting to setup a session to the server. This is
+ when attempting to setup a session to the server.
This is needed for mounting to some older servers (such
as OS/2 or Windows 98 and Windows ME) since they do not
support a default server name. A server name can be up
sign Must use packet signing (helps avoid unwanted data modification
by intermediate systems in the route). Note that signing
does not work with lanman or plaintext authentication.
+ seal Must seal (encrypt) all data on this mounted share before
+ sending on the network. Requires support for Unix Extensions.
+ Note that this differs from the sign mount option in that it
+ causes encryption of data sent over this mounted share but other
+ shares mounted to the same server are unaffected.
+ locallease This option is rarely needed. Fcntl F_SETLEASE is
+ used by some applications such as Samba and NFSv4 server to
+ check to see whether a file is cacheable. CIFS has no way
+ to explicitly request a lease, but can check whether a file
+ is cacheable (oplocked). Unfortunately, even if a file
+ is not oplocked, it could still be cacheable (ie cifs client
+ could grant fcntl leases if no other local processes are using
+ the file) for cases for example such as when the server does not
+ support oplocks and the user is sure that the only updates to
+ the file will be from this client. Specifying this mount option
+ will allow the cifs client to check for leases (only) locally
+ for files which are not oplocked instead of denying leases
+ in that case. (EXPERIMENTAL)
sec Security mode. Allowed values are:
none attempt to connection as a null user (no name)
krb5 Use Kerberos version 5 authentication
hashing mechanisms (as "must use") on the other hand
does not make much sense. Default flags are
0x07007
- (NTLM, NTLMv2 and packet signing allowed). Maximum
+ (NTLM, NTLMv2 and packet signing allowed). The maximum
allowable flags if you want to allow mounts to servers
using weaker password hashes is 0x37037 (lanman,
- plaintext, ntlm, ntlmv2, signing allowed):
+ plaintext, ntlm, ntlmv2, signing allowed). Some
+ SecurityFlags require the corresponding menuconfig
+ options to be enabled (lanman and plaintext require
+ CONFIG_CIFS_WEAK_PW_HASH for example). Enabling
+ plaintext authentication currently requires also
+ enabling lanman authentication in the security flags
+ because the cifs module only supports sending
+ laintext passwords using the older lanman dialect
+ form of the session setup SMB. (e.g. for authentication
+ using plain text passwords, set the SecurityFlags
+ to 0x30030):
may use packet signing 0x00001
must use packet signing 0x01001
signing turned on in case buffer was modified
just before it was sent, also this flag will
be used to use the new experimental directory change
- notification code).
+ notification code). When set to 2 enables
+ an additional experimental feature, "raw ntlmssp"
+ session establishment support (which allows
+ specifying "sec=ntlmssp" on mount). The Linux cifs
+ module will use ntlmv2 authentication encapsulated
+ in "raw ntlmssp" (not using SPNEGO) when
+ "sec=ntlmssp" is specified on mount.
+ This support also requires building cifs with
+ the CONFIG_CIFS_EXPERIMENTAL configuration flag.
These experimental features and tracing can be enabled by changing flags in
/proc/fs/cifs (after the cifs module has been installed or built into the
cifsacl support needed to retrieve approximated mode bits based on
the contents on the CIFS ACL.
+ lease support: cifs will check the oplock state before calling into
+ the vfs to see if we can grant a lease on a file.
+
DNOTIFY fcntl: needed for support of directory change
notification and perhaps later for file leases)
that they represent all for that share, not just those for which the server
returned success.
-Also note that "cat /proc/fs/cifs/DebugData" will display information about
+Also note that "cat /proc/fs/cifs/DebugData" will display information about
the active sessions and the shares that are mounted.
-Enabling Kerberos (extended security) works when CONFIG_CIFS_EXPERIMENTAL is
-on but requires a user space helper (from the Samba project). NTLM and NTLMv2 and
-LANMAN support do not require this helper.
+
+Enabling Kerberos (extended security) works but requires version 1.2 or later
+of the helper program cifs.upcall to be present and to be configured in the
+/etc/request-key.conf file. The cifs.upcall helper program is from the Samba
+project(http://www.samba.org). NTLM and NTLMv2 and LANMAN support do not
+require this helper. Note that NTLMv2 security (which does not require the
+cifs.upcall helper program), instead of using Kerberos, is sufficient for
+some use cases.
+
+DFS support allows transparent redirection to shares in an MS-DFS name space.
+In addition, DFS support for target shares which are specified as UNC
+names which begin with host names (rather than IP addresses) requires
+a user space helper (such as cifs.upcall) to be present in order to
+translate host names to ip address, and the user space helper must also
+be configured in the file /etc/request-key.conf. Samba, Windows servers and
+many NAS appliances support DFS as a way of constructing a global name
+space to ease network configuration and improve reliability.
+
+To use cifs Kerberos and DFS support, the Linux keyutils package should be
+installed and something like the following lines should be added to the
+/etc/request-key.conf file:
+
+create cifs.spnego * * /usr/local/sbin/cifs.upcall %k
+create dns_resolver * * /usr/local/sbin/cifs.upcall %k
+
+
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff