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path: root/fs/smb/client/fs_context.h
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2025-05-01smb: client: ensure aligned IO sizesPaulo Alcantara
Make all IO sizes multiple of PAGE_SIZE, either negotiated by the server or passed through rsize, wsize and bsize mount options, to prevent from breaking DIO reads and writes against servers that enforce alignment as specified in MS-FSA 2.1.5.3 and 2.1.5.4. Cc: linux-cifs@vger.kernel.org Reviewed-by: David Howells <dhowells@redhat.com> Signed-off-by: Paulo Alcantara (Red Hat) <pc@manguebit.com> Signed-off-by: Steve French <stfrench@microsoft.com>
2025-04-01cifs: Allow to disable or force initialization of NetBIOS sessionPali Rohár
Currently SMB client always tries to initialize NetBIOS session when the server port is 139. This is useful for default cases, but nowadays when using non-standard routing or testing between VMs, it is common that servers are listening on non-standard ports. So add a new mount option -o nbsessinit and -o nonbsessinit which either forces initialization or disables initialization regardless of server port number. This allows Linux SMB client to connect to older SMB1 server listening on non-standard port, which requires initialization of NetBIOS session, by using additional mount options -o port= and -o nbsessinit. Signed-off-by: Pali Rohár <pali@kernel.org> Signed-off-by: Steve French <stfrench@microsoft.com>
2025-03-31smb: client: Store original IO parameters and prevent zero IO sizesWang Zhaolong
During mount option processing and negotiation with the server, the original user-specified rsize/wsize values were being modified directly. This makes it impossible to recover these values after a connection reset, leading to potential degraded performance after reconnection. The other problem is that When negotiating read and write sizes, there are cases where the negotiated values might calculate to zero, especially during reconnection when server->max_read or server->max_write might be reset. In general, these values come from the negotiation response. According to MS-SMB2 specification, these values should be at least 65536 bytes. This patch improves IO parameter handling: 1. Adds vol_rsize and vol_wsize fields to store the original user-specified values separately from the negotiated values 2. Uses got_rsize/got_wsize flags to determine if values were user-specified rather than checking for non-zero values, which is more reliable 3. Adds a prevent_zero_iosize() helper function to ensure IO sizes are never negotiated down to zero, which could happen in edge cases like when server->max_read/write is zero The changes make the CIFS client more resilient to unusual server responses and reconnection scenarios, preventing potential failures when IO sizes are calculated to be zero. Signed-off-by: Wang Zhaolong <wangzhaolong1@huawei.com> Signed-off-by: Steve French <stfrench@microsoft.com>
2025-03-26cifs: Add new mount option -o nounicode to disable SMB1 UNICODE modePali Rohár
SMB1 protocol supports non-UNICODE (8-bit OEM character set) and UNICODE (UTF-16) modes. Linux SMB1 client implements both of them but currently does not allow to choose non-UNICODE mode when SMB1 server announce UNICODE mode support. This change adds a new mount option -o nounicode to disable UNICODE mode and force usage of non-UNICODE (8-bit OEM character set) mode. This allows to test non-UNICODE implementation of Linux SMB1 client against any SMB1 server, including modern and recent Windows SMB1 server. Signed-off-by: Pali Rohár <pali@kernel.org> Signed-off-by: Steve French <stfrench@microsoft.com>
2025-01-31cifs: Add support for creating native Windows socketsPali Rohár
Native Windows sockets created by WinSock on Windows 10 April 2018 Update (version 1803) or Windows Server 2019 (version 1809) or later versions is reparse point with IO_REPARSE_TAG_AF_UNIX tag, with empty reparse point data buffer and without any EAs. Create AF_UNIX sockets in this native format if -o nonativesocket was not specified. This change makes AF_UNIX sockets created by Linux CIFS client compatible with AF_UNIX sockets created by Windows applications on NTFS volumes. Signed-off-by: Pali Rohár <pali@kernel.org> Signed-off-by: Steve French <stfrench@microsoft.com>
2025-01-29cifs: Add mount option -o reparse=nonePali Rohár
This new mount option allows to completely disable creating new reparse points. When -o sfu or -o mfsymlinks or -o symlink= is not specified then creating any special file (fifo, socket, symlink, block and char) will fail with -EOPNOTSUPP error. Signed-off-by: Pali Rohár <pali@kernel.org> Signed-off-by: Steve French <stfrench@microsoft.com>
2025-01-29cifs: Add mount option -o symlink= for choosing symlink create typePali Rohár
Currently Linux CIFS client creates a new symlink of the first flavor which is allowed by mount options, parsed in this order: -o (no)mfsymlinks, -o (no)sfu, -o (no)unix (+ its aliases) and -o reparse=[type]. Introduce a new mount option -o symlink= for explicitly choosing a symlink flavor. Possible options are: -o symlink=default - The default behavior, like before this change. -o symlink=none - Disallow creating a new symlinks -o symlink=native - Create as native SMB symlink reparse point -o symlink=unix - Create via SMB1 unix extension command -o symlink=mfsymlinks - Create as regular file of mfsymlinks format -o symlink=sfu - Create as regular system file of SFU format -o symlink=nfs - Create as NFS reparse point -o symlink=wsl - Create as WSL reparse point So for example specifying -o sfu,mfsymlinks,symlink=native will allow to parse symlinks also of SFU and mfsymlinks types (which are disabled by default unless mount option is explicitly specified), but new symlinks will be created under native SMB type (which parsing is always enabled). Signed-off-by: Pali Rohár <pali@kernel.org> Signed-off-by: Steve French <stfrench@microsoft.com>
2025-01-29cifs: Fix creating and resolving absolute NT-style symlinksPali Rohár
If the SMB symlink is stored on NT server in absolute form then it points to the NT object hierarchy, which is different from POSIX one and needs some conversion / mapping. To make interoperability with Windows SMB server and WSL subsystem, reuse its logic of mapping between NT paths and POSIX paths into Linux SMB client. WSL subsystem on Windows uses for -t drvfs mount option -o symlinkroot= which specifies the POSIX path where are expected to be mounted lowercase Windows drive letters (without colon). Do same for Linux SMB client and add a new mount option -o symlinkroot= which mimics the drvfs mount option of the same name. It specifies where in the Linux VFS hierarchy is the root of the DOS / Windows drive letters, and translates between absolute NT-style symlinks and absolute Linux VFS symlinks. Default value of symlinkroot is "/mnt", same what is using WSL. Note that DOS / Windows drive letter symlinks are just subset of all possible NT-style symlinks. Drive letters live in NT subtree \??\ and important details about NT paths and object hierarchy are in the comments in this change. When symlink target location from non-POSIX SMB server is in absolute form (indicated by absence of SYMLINK_FLAG_RELATIVE) then it is converted to Linux absolute symlink according to symlinkroot configuration. And when creating a new symlink on non-POSIX SMB server in absolute form then Linux absolute target is converted to NT-style according to symlinkroot configuration. When SMB server is POSIX, then this change does not affect neither reading target location of symlink, nor creating a new symlink. It is expected that POSIX SMB server works with POSIX paths where the absolute root is /. This change improves interoperability of absolute SMB symlinks with Windows SMB servers. Signed-off-by: Pali Rohár <pali@kernel.org> Signed-off-by: Steve French <stfrench@microsoft.com>
2025-01-19smb: client: fix DFS mount against old servers with NTLMSSPPaulo Alcantara
Old Windows servers will return not fully qualified DFS targets by default as specified in MS-DFSC 3.2.5.5 Receiving a Root Referral Request or Link Referral Request | Servers SHOULD<30> return fully qualified DNS host names of | targets in responses to root referral requests and link referral | requests. | ... | <30> Section 3.2.5.5: By default, Windows Server 2003, Windows | Server 2008, Windows Server 2008 R2, Windows Server 2012, and | Windows Server 2012 R2 return DNS host names that are not fully | qualified for targets. Fix this by converting all NetBIOS host names from DFS targets to FQDNs and try resolving them first if DNS domain name was provided in NTLMSSP CHALLENGE_MESSAGE message from previous SMB2_SESSION_SETUP. This also prevents the client from translating the DFS target hostnames to another domain depending on the network domain search order. Signed-off-by: Paulo Alcantara (Red Hat) <pc@manguebit.com> Signed-off-by: Steve French <stfrench@microsoft.com>
2024-11-28cifs: during remount, make sure passwords are in syncShyam Prasad N
This fixes scenarios where remount can overwrite the only currently working password, breaking reconnect. We recently introduced a password2 field in both ses and ctx structs. This was done so as to allow the client to rotate passwords for a mount without any downtime. However, when the client transparently handles password rotation, it can swap the values of the two password fields in the ses struct, but not in smb3_fs_context struct that hangs off cifs_sb. This can lead to a situation where a remount unintentionally overwrites a working password in the ses struct. In order to fix this, we first get the passwords in ctx struct in-sync with ses struct, before replacing them with what the passwords that could be passed as a part of remount. Also, in order to avoid race condition between smb2_reconnect and smb3_reconfigure, we make sure to lock session_mutex before changing password and password2 fields of the ses structure. Fixes: 35f834265e0d ("smb3: fix broken reconnect when password changing on the server by allowing password rotation") Signed-off-by: Shyam Prasad N <sprasad@microsoft.com> Signed-off-by: Meetakshi Setiya <msetiya@microsoft.com> Signed-off-by: Steve French <stfrench@microsoft.com>
2024-11-21CIFS: New mount option for cifs.upcall namespace resolutionRitvik Budhiraja
In the current implementation, the SMB filesystem on a mount point can trigger upcalls from the kernel to the userspace to enable certain functionalities like spnego, dns_resolution, amongst others. These upcalls usually either happen in the context of the mount or in the context of an application/user. The upcall handler for cifs, cifs.upcall already has existing code which switches the namespaces to the caller's namespace before handling the upcall. This behaviour is expected for scenarios like multiuser mounts, but might not cover all single user scenario with services such as Kubernetes, where the mount can happen from different locations such as on the host, from an app container, or a driver pod which does the mount on behalf of a different pod. This patch introduces a new mount option called upcall_target, to customise the upcall behaviour. upcall_target can take 'mount' and 'app' as possible values. This aids use cases like Kubernetes where the mount happens on behalf of the application in another container altogether. Having this new mount option allows the mount command to specify where the upcall should happen: 'mount' for resolving the upcall to the host namespace, and 'app' for resolving the upcall to the ns of the calling thread. This will enable both the scenarios where the Kerberos credentials can be found on the application namespace or the host namespace to which just the mount operation is "delegated". Reviewed-by: Shyam Prasad <shyam.prasad@microsoft.com> Reviewed-by: Bharath S M <bharathsm@microsoft.com> Reviewed-by: Ronnie Sahlberg <ronniesahlberg@gmail.com> Signed-off-by: Ritvik Budhiraja <rbudhiraja@microsoft.com> Signed-off-by: Steve French <stfrench@microsoft.com>
2024-10-02smb: client: Correct typos in multiple comments across various filesShen Lichuan
Fixed some confusing typos that were currently identified witch codespell, the details are as follows: -in the code comments: fs/smb/client/cifsacl.h:58: inheritence ==> inheritance fs/smb/client/cifsencrypt.c:242: origiginal ==> original fs/smb/client/cifsfs.c:164: referece ==> reference fs/smb/client/cifsfs.c:292: ned ==> need fs/smb/client/cifsglob.h:779: initital ==> initial fs/smb/client/cifspdu.h:784: altetnative ==> alternative fs/smb/client/cifspdu.h:2409: conrol ==> control fs/smb/client/cifssmb.c:1218: Expirement ==> Experiment fs/smb/client/cifssmb.c:3021: conver ==> convert fs/smb/client/cifssmb.c:3998: asterik ==> asterisk fs/smb/client/file.c:2505: useable ==> usable fs/smb/client/fs_context.h:263: timemout ==> timeout fs/smb/client/misc.c:257: responsbility ==> responsibility fs/smb/client/netmisc.c:1006: divisable ==> divisible fs/smb/client/readdir.c:556: endianess ==> endianness fs/smb/client/readdir.c:818: bu ==> by fs/smb/client/smb2ops.c:2180: snaphots ==> snapshots fs/smb/client/smb2ops.c:3586: otions ==> options fs/smb/client/smb2pdu.c:2979: timestaps ==> timestamps fs/smb/client/smb2pdu.c:4574: memmory ==> memory fs/smb/client/smb2transport.c:699: origiginal ==> original fs/smb/client/smbdirect.c:222: happenes ==> happens fs/smb/client/smbdirect.c:1347: registartions ==> registrations fs/smb/client/smbdirect.h:114: accoutning ==> accounting Signed-off-by: Shen Lichuan <shenlichuan@vivo.com> Signed-off-by: Steve French <stfrench@microsoft.com>
2024-09-24smb: client: fix DFS interlink failoverPaulo Alcantara
The DFS interlinks point to different DFS namespaces so make sure to use the correct DFS root server to chase any DFS links under it by storing the SMB session in dfs_ref_walk structure and then using it on every referral walk. Signed-off-by: Paulo Alcantara (Red Hat) <pc@manguebit.com> Signed-off-by: Steve French <stfrench@microsoft.com>
2024-04-22cifs: reinstate original behavior again for forceuid/forcegidTakayuki Nagata
forceuid/forcegid should be enabled by default when uid=/gid= options are specified, but commit 24e0a1eff9e2 ("cifs: switch to new mount api") changed the behavior. Due to the change, a mounted share does not show intentional uid/gid for files and directories even though uid=/gid= options are specified since forceuid/forcegid are not enabled. This patch reinstates original behavior that overrides uid/gid with specified uid/gid by the options. Fixes: 24e0a1eff9e2 ("cifs: switch to new mount api") Signed-off-by: Takayuki Nagata <tnagata@redhat.com> Acked-by: Paulo Alcantara (Red Hat) <pc@manguebit.com> Acked-by: Ronnie Sahlberg <lsahlber@redhat.com> Acked-by: Tom Talpey <tom@talpey.com> Signed-off-by: Steve French <stfrench@microsoft.com>
2024-04-11smb3: fix broken reconnect when password changing on the server by allowing ↵Steve French
password rotation There are various use cases that are becoming more common in which password changes are scheduled on a server(s) periodically but the clients connected to this server need to stay connected (even in the face of brief network reconnects) due to mounts which can not be easily unmounted and mounted at will, and servers that do password rotation do not always have the ability to tell the clients exactly when to the new password will be effective, so add support for an alt password ("password2=") on mount (and also remount) so that we can anticipate the upcoming change to the server without risking breaking existing mounts. An alternative would have been to use the kernel keyring for this but the processes doing the reconnect do not have access to the keyring but do have access to the ses structure. Reviewed-by: Bharath SM <bharathsm@microsoft.com> Signed-off-by: Steve French <stfrench@microsoft.com>
2024-04-02smb: client: serialise cifs_construct_tcon() with cifs_mount_mutexPaulo Alcantara
Serialise cifs_construct_tcon() with cifs_mount_mutex to handle parallel mounts that may end up reusing the session and tcon created by it. Cc: stable@vger.kernel.org # 6.4+ Signed-off-by: Paulo Alcantara (Red Hat) <pc@manguebit.com> Signed-off-by: Steve French <stfrench@microsoft.com>
2024-03-10smb: client: negotiate compression algorithmsEnzo Matsumiya
Change "compress=" mount option to a boolean flag, that, if set, will enable negotiating compression algorithms with the server. Do not de/compress anything for now. Signed-off-by: Enzo Matsumiya <ematsumiya@suse.de> Signed-off-by: Steve French <stfrench@microsoft.com>
2024-03-10smb: client: introduce reparse mount optionPaulo Alcantara
Allow the user to create special files and symlinks by choosing between WSL and NFS reparse points via 'reparse={nfs,wsl}' mount options. If unset or 'reparse=default', the client will default to creating them via NFS reparse points. Creating WSL reparse points isn't supported yet, so simply return error when attempting to mount with 'reparse=wsl' for now. Signed-off-by: Paulo Alcantara <pc@manguebit.com> Signed-off-by: Steve French <stfrench@microsoft.com>
2024-01-19cifs: new mount option called retransShyam Prasad N
We have several places in the code where we treat the error -EAGAIN very differently. Some code retry for arbitrary number of times. Introducing this new mount option named "retrans", so that all these handlers of -EAGAIN can retry a fixed number of times. This applies only to soft mounts. Signed-off-by: Shyam Prasad N <sprasad@microsoft.com> Signed-off-by: Steve French <stfrench@microsoft.com>
2023-11-09smb: client: fix mount when dns_resolver key is not availablePaulo Alcantara
There was a wrong assumption that with CONFIG_CIFS_DFS_UPCALL=y there would always be a dns_resolver key set up so we could unconditionally upcall to resolve UNC hostname rather than using the value provided by mount(2). Only require it when performing automount of junctions within a DFS share so users that don't have dns_resolver key still can mount their regular shares with server hostname resolved by mount.cifs(8). Fixes: 348a04a8d113 ("smb: client: get rid of dfs code dep in namespace.c") Cc: stable@vger.kernel.org Tested-by: Eduard Bachmakov <e.bachmakov@gmail.com> Reported-by: Eduard Bachmakov <e.bachmakov@gmail.com> Closes: https://lore.kernel.org/all/CADCRUiNvZuiUZ0VGZZO9HRyPyw6x92kiA7o7Q4tsX5FkZqUkKg@mail.gmail.com/ Signed-off-by: Paulo Alcantara (SUSE) <pc@manguebit.com> Signed-off-by: Steve French <stfrench@microsoft.com>
2023-09-07smb3: allow controlling maximum number of cached directoriesSteve French
Allow adjusting the maximum number of cached directories per share (defaults to 16) via mount parm "max_cached_dirs" Signed-off-by: Steve French <stfrench@microsoft.com>
2023-05-24smb: move client and server files to common directory fs/smbSteve French
Move CIFS/SMB3 related client and server files (cifs.ko and ksmbd.ko and helper modules) to new fs/smb subdirectory: fs/cifs --> fs/smb/client fs/ksmbd --> fs/smb/server fs/smbfs_common --> fs/smb/common Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Namjae Jeon <linkinjeon@kernel.org> Signed-off-by: Steve French <stfrench@microsoft.com>