summaryrefslogtreecommitdiff
path: root/fs/cifs
AgeCommit message (Collapse)Author
2017-03-03Merge branch 'for-next' of git://git.samba.org/sfrench/cifs-2.6Linus Torvalds
Pull SMB3 fixes from Steve French: "Some small bug fixes as well as SMB2.1/SMB3 enablement for DFS (global namespace) which previously was only enabled for CIFS" * 'for-next' of git://git.samba.org/sfrench/cifs-2.6: smb2: Enforce sec= mount option CIFS: Fix sparse warnings CIFS: implement get_dfs_refer for SMB2+ CIFS: use DFS pathnames in SMB2+ Create requests CIFS: set signing flag in SMB2+ TreeConnect if needed CIFS: let ses->ipc_tid hold smb2 TreeIds CIFS: add use_ipc flag to SMB2_ioctl() CIFS: add build_path_from_dentry_optional_prefix() CIFS: move DFS response parsing out of SMB1 code CIFS: Fix possible use after free in demultiplex thread
2017-03-03Merge branch 'rebased-statx' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull vfs 'statx()' update from Al Viro. This adds the new extended stat() interface that internally subsumes our previous stat interfaces, and allows user mode to specify in more detail what kind of information it wants. It also allows for some explicit synchronization information to be passed to the filesystem, which can be relevant for network filesystems: is the cached value ok, or do you need open/close consistency, or what? From David Howells. Andreas Dilger points out that the first version of the extended statx interface was posted June 29, 2010: https://www.spinics.net/lists/linux-fsdevel/msg33831.html * 'rebased-statx' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: statx: Add a system call to make enhanced file info available
2017-03-03Merge branch 'WIP.sched-core-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull sched.h split-up from Ingo Molnar: "The point of these changes is to significantly reduce the <linux/sched.h> header footprint, to speed up the kernel build and to have a cleaner header structure. After these changes the new <linux/sched.h>'s typical preprocessed size goes down from a previous ~0.68 MB (~22K lines) to ~0.45 MB (~15K lines), which is around 40% faster to build on typical configs. Not much changed from the last version (-v2) posted three weeks ago: I eliminated quirks, backmerged fixes plus I rebased it to an upstream SHA1 from yesterday that includes most changes queued up in -next plus all sched.h changes that were pending from Andrew. I've re-tested the series both on x86 and on cross-arch defconfigs, and did a bisectability test at a number of random points. I tried to test as many build configurations as possible, but some build breakage is probably still left - but it should be mostly limited to architectures that have no cross-compiler binaries available on kernel.org, and non-default configurations" * 'WIP.sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (146 commits) sched/headers: Clean up <linux/sched.h> sched/headers: Remove #ifdefs from <linux/sched.h> sched/headers: Remove the <linux/topology.h> include from <linux/sched.h> sched/headers, hrtimer: Remove the <linux/wait.h> include from <linux/hrtimer.h> sched/headers, x86/apic: Remove the <linux/pm.h> header inclusion from <asm/apic.h> sched/headers, timers: Remove the <linux/sysctl.h> include from <linux/timer.h> sched/headers: Remove <linux/magic.h> from <linux/sched/task_stack.h> sched/headers: Remove <linux/sched.h> from <linux/sched/init.h> sched/core: Remove unused prefetch_stack() sched/headers: Remove <linux/rculist.h> from <linux/sched.h> sched/headers: Remove the 'init_pid_ns' prototype from <linux/sched.h> sched/headers: Remove <linux/signal.h> from <linux/sched.h> sched/headers: Remove <linux/rwsem.h> from <linux/sched.h> sched/headers: Remove the runqueue_is_locked() prototype sched/headers: Remove <linux/sched.h> from <linux/sched/hotplug.h> sched/headers: Remove <linux/sched.h> from <linux/sched/debug.h> sched/headers: Remove <linux/sched.h> from <linux/sched/nohz.h> sched/headers: Remove <linux/sched.h> from <linux/sched/stat.h> sched/headers: Remove the <linux/gfp.h> include from <linux/sched.h> sched/headers: Remove <linux/rtmutex.h> from <linux/sched.h> ...
2017-03-02smb2: Enforce sec= mount optionSachin Prabhu
If the security type specified using a mount option is not supported, the SMB2 session setup code changes the security type to RawNTLMSSP. We should instead fail the mount and return an error. The patch changes the code for SMB2 to make it similar to the code used for SMB1. Like in SMB1, we now use the global security flags to select the security method to be used when no security method is specified and to return an error when the requested auth method is not available. For SMB2, we also use ntlmv2 as a synonym for nltmssp. Signed-off-by: Sachin Prabhu <sprabhu@redhat.com> Acked-by: Pavel Shilovsky <pshilov@microsoft.com> Acked-by: Jeff Layton <jlayton@redhat.com> Signed-off-by: Steve French <smfrench@gmail.com>
2017-03-02CIFS: Fix sparse warningsSteve French
Fix two minor sparse compile check warnings Signed-off-by: Steve French <steve.french@primarydata.com> Acked-by: Pavel Shilovsky <pshilov@microsoft.com> Reviewed-by: Aurelien Aptel <aaptel@suse.com>
2017-03-02statx: Add a system call to make enhanced file info availableDavid Howells
Add a system call to make extended file information available, including file creation and some attribute flags where available through the underlying filesystem. The getattr inode operation is altered to take two additional arguments: a u32 request_mask and an unsigned int flags that indicate the synchronisation mode. This change is propagated to the vfs_getattr*() function. Functions like vfs_stat() are now inline wrappers around new functions vfs_statx() and vfs_statx_fd() to reduce stack usage. ======== OVERVIEW ======== The idea was initially proposed as a set of xattrs that could be retrieved with getxattr(), but the general preference proved to be for a new syscall with an extended stat structure. A number of requests were gathered for features to be included. The following have been included: (1) Make the fields a consistent size on all arches and make them large. (2) Spare space, request flags and information flags are provided for future expansion. (3) Better support for the y2038 problem [Arnd Bergmann] (tv_sec is an __s64). (4) Creation time: The SMB protocol carries the creation time, which could be exported by Samba, which will in turn help CIFS make use of FS-Cache as that can be used for coherency data (stx_btime). This is also specified in NFSv4 as a recommended attribute and could be exported by NFSD [Steve French]. (5) Lightweight stat: Ask for just those details of interest, and allow a netfs (such as NFS) to approximate anything not of interest, possibly without going to the server [Trond Myklebust, Ulrich Drepper, Andreas Dilger] (AT_STATX_DONT_SYNC). (6) Heavyweight stat: Force a netfs to go to the server, even if it thinks its cached attributes are up to date [Trond Myklebust] (AT_STATX_FORCE_SYNC). And the following have been left out for future extension: (7) Data version number: Could be used by userspace NFS servers [Aneesh Kumar]. Can also be used to modify fill_post_wcc() in NFSD which retrieves i_version directly, but has just called vfs_getattr(). It could get it from the kstat struct if it used vfs_xgetattr() instead. (There's disagreement on the exact semantics of a single field, since not all filesystems do this the same way). (8) BSD stat compatibility: Including more fields from the BSD stat such as creation time (st_btime) and inode generation number (st_gen) [Jeremy Allison, Bernd Schubert]. (9) Inode generation number: Useful for FUSE and userspace NFS servers [Bernd Schubert]. (This was asked for but later deemed unnecessary with the open-by-handle capability available and caused disagreement as to whether it's a security hole or not). (10) Extra coherency data may be useful in making backups [Andreas Dilger]. (No particular data were offered, but things like last backup timestamp, the data version number and the DOS archive bit would come into this category). (11) Allow the filesystem to indicate what it can/cannot provide: A filesystem can now say it doesn't support a standard stat feature if that isn't available, so if, for instance, inode numbers or UIDs don't exist or are fabricated locally... (This requires a separate system call - I have an fsinfo() call idea for this). (12) Store a 16-byte volume ID in the superblock that can be returned in struct xstat [Steve French]. (Deferred to fsinfo). (13) Include granularity fields in the time data to indicate the granularity of each of the times (NFSv4 time_delta) [Steve French]. (Deferred to fsinfo). (14) FS_IOC_GETFLAGS value. These could be translated to BSD's st_flags. Note that the Linux IOC flags are a mess and filesystems such as Ext4 define flags that aren't in linux/fs.h, so translation in the kernel may be a necessity (or, possibly, we provide the filesystem type too). (Some attributes are made available in stx_attributes, but the general feeling was that the IOC flags were to ext[234]-specific and shouldn't be exposed through statx this way). (15) Mask of features available on file (eg: ACLs, seclabel) [Brad Boyer, Michael Kerrisk]. (Deferred, probably to fsinfo. Finding out if there's an ACL or seclabal might require extra filesystem operations). (16) Femtosecond-resolution timestamps [Dave Chinner]. (A __reserved field has been left in the statx_timestamp struct for this - if there proves to be a need). (17) A set multiple attributes syscall to go with this. =============== NEW SYSTEM CALL =============== The new system call is: int ret = statx(int dfd, const char *filename, unsigned int flags, unsigned int mask, struct statx *buffer); The dfd, filename and flags parameters indicate the file to query, in a similar way to fstatat(). There is no equivalent of lstat() as that can be emulated with statx() by passing AT_SYMLINK_NOFOLLOW in flags. There is also no equivalent of fstat() as that can be emulated by passing a NULL filename to statx() with the fd of interest in dfd. Whether or not statx() synchronises the attributes with the backing store can be controlled by OR'ing a value into the flags argument (this typically only affects network filesystems): (1) AT_STATX_SYNC_AS_STAT tells statx() to behave as stat() does in this respect. (2) AT_STATX_FORCE_SYNC will require a network filesystem to synchronise its attributes with the server - which might require data writeback to occur to get the timestamps correct. (3) AT_STATX_DONT_SYNC will suppress synchronisation with the server in a network filesystem. The resulting values should be considered approximate. mask is a bitmask indicating the fields in struct statx that are of interest to the caller. The user should set this to STATX_BASIC_STATS to get the basic set returned by stat(). It should be noted that asking for more information may entail extra I/O operations. buffer points to the destination for the data. This must be 256 bytes in size. ====================== MAIN ATTRIBUTES RECORD ====================== The following structures are defined in which to return the main attribute set: struct statx_timestamp { __s64 tv_sec; __s32 tv_nsec; __s32 __reserved; }; struct statx { __u32 stx_mask; __u32 stx_blksize; __u64 stx_attributes; __u32 stx_nlink; __u32 stx_uid; __u32 stx_gid; __u16 stx_mode; __u16 __spare0[1]; __u64 stx_ino; __u64 stx_size; __u64 stx_blocks; __u64 __spare1[1]; struct statx_timestamp stx_atime; struct statx_timestamp stx_btime; struct statx_timestamp stx_ctime; struct statx_timestamp stx_mtime; __u32 stx_rdev_major; __u32 stx_rdev_minor; __u32 stx_dev_major; __u32 stx_dev_minor; __u64 __spare2[14]; }; The defined bits in request_mask and stx_mask are: STATX_TYPE Want/got stx_mode & S_IFMT STATX_MODE Want/got stx_mode & ~S_IFMT STATX_NLINK Want/got stx_nlink STATX_UID Want/got stx_uid STATX_GID Want/got stx_gid STATX_ATIME Want/got stx_atime{,_ns} STATX_MTIME Want/got stx_mtime{,_ns} STATX_CTIME Want/got stx_ctime{,_ns} STATX_INO Want/got stx_ino STATX_SIZE Want/got stx_size STATX_BLOCKS Want/got stx_blocks STATX_BASIC_STATS [The stuff in the normal stat struct] STATX_BTIME Want/got stx_btime{,_ns} STATX_ALL [All currently available stuff] stx_btime is the file creation time, stx_mask is a bitmask indicating the data provided and __spares*[] are where as-yet undefined fields can be placed. Time fields are structures with separate seconds and nanoseconds fields plus a reserved field in case we want to add even finer resolution. Note that times will be negative if before 1970; in such a case, the nanosecond fields will also be negative if not zero. The bits defined in the stx_attributes field convey information about a file, how it is accessed, where it is and what it does. The following attributes map to FS_*_FL flags and are the same numerical value: STATX_ATTR_COMPRESSED File is compressed by the fs STATX_ATTR_IMMUTABLE File is marked immutable STATX_ATTR_APPEND File is append-only STATX_ATTR_NODUMP File is not to be dumped STATX_ATTR_ENCRYPTED File requires key to decrypt in fs Within the kernel, the supported flags are listed by: KSTAT_ATTR_FS_IOC_FLAGS [Are any other IOC flags of sufficient general interest to be exposed through this interface?] New flags include: STATX_ATTR_AUTOMOUNT Object is an automount trigger These are for the use of GUI tools that might want to mark files specially, depending on what they are. Fields in struct statx come in a number of classes: (0) stx_dev_*, stx_blksize. These are local system information and are always available. (1) stx_mode, stx_nlinks, stx_uid, stx_gid, stx_[amc]time, stx_ino, stx_size, stx_blocks. These will be returned whether the caller asks for them or not. The corresponding bits in stx_mask will be set to indicate whether they actually have valid values. If the caller didn't ask for them, then they may be approximated. For example, NFS won't waste any time updating them from the server, unless as a byproduct of updating something requested. If the values don't actually exist for the underlying object (such as UID or GID on a DOS file), then the bit won't be set in the stx_mask, even if the caller asked for the value. In such a case, the returned value will be a fabrication. Note that there are instances where the type might not be valid, for instance Windows reparse points. (2) stx_rdev_*. This will be set only if stx_mode indicates we're looking at a blockdev or a chardev, otherwise will be 0. (3) stx_btime. Similar to (1), except this will be set to 0 if it doesn't exist. ======= TESTING ======= The following test program can be used to test the statx system call: samples/statx/test-statx.c Just compile and run, passing it paths to the files you want to examine. The file is built automatically if CONFIG_SAMPLES is enabled. Here's some example output. Firstly, an NFS directory that crosses to another FSID. Note that the AUTOMOUNT attribute is set because transiting this directory will cause d_automount to be invoked by the VFS. [root@andromeda ~]# /tmp/test-statx -A /warthog/data statx(/warthog/data) = 0 results=7ff Size: 4096 Blocks: 8 IO Block: 1048576 directory Device: 00:26 Inode: 1703937 Links: 125 Access: (3777/drwxrwxrwx) Uid: 0 Gid: 4041 Access: 2016-11-24 09:02:12.219699527+0000 Modify: 2016-11-17 10:44:36.225653653+0000 Change: 2016-11-17 10:44:36.225653653+0000 Attributes: 0000000000001000 (-------- -------- -------- -------- -------- -------- ---m---- --------) Secondly, the result of automounting on that directory. [root@andromeda ~]# /tmp/test-statx /warthog/data statx(/warthog/data) = 0 results=7ff Size: 4096 Blocks: 8 IO Block: 1048576 directory Device: 00:27 Inode: 2 Links: 125 Access: (3777/drwxrwxrwx) Uid: 0 Gid: 4041 Access: 2016-11-24 09:02:12.219699527+0000 Modify: 2016-11-17 10:44:36.225653653+0000 Change: 2016-11-17 10:44:36.225653653+0000 Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2017-03-02CIFS: implement get_dfs_refer for SMB2+Aurelien Aptel
in SMB2+ the get_dfs_refer operation uses a FSCTL. The request can be made on any Tree Connection according to the specs. Since Samba only accepted it on an IPC connection until recently, try that first. https://lists.samba.org/archive/samba-technical/2017-February/118859.html 3.2.4.20.3 Application Requests DFS Referral Information: > The client MUST search for an existing Session and TreeConnect to any > share on the server identified by ServerName for the user identified by > UserCredentials. If no Session and TreeConnect are found, the client > MUST establish a new Session and TreeConnect to IPC$ on the target > server as described in section 3.2.4.2 using the supplied ServerName and > UserCredentials. Signed-off-by: Aurelien Aptel <aaptel@suse.com> Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com> Signed-off-by: Steve French <smfrench@gmail.com>
2017-03-02CIFS: use DFS pathnames in SMB2+ Create requestsAurelien Aptel
When connected to a DFS capable share, the client must set the SMB2_FLAGS_DFS_OPERATIONS flag in the SMB2 header and use DFS path names: "<server>\<share>\<path>" *without* leading \\. Sources: [MS-SMB2] 3.2.5.5 Receiving an SMB2 TREE_CONNECT Response > TreeConnect.IsDfsShare MUST be set to TRUE, if the SMB2_SHARE_CAP_DFS > bit is set in the Capabilities field of the response. [MS-SMB2] 3.2.4.3 Application Requests Opening a File > If TreeConnect.IsDfsShare is TRUE, the SMB2_FLAGS_DFS_OPERATIONS flag > is set in the Flags field. [MS-SMB2] 2.2.13 SMB2 CREATE Request, NameOffset: > If SMB2_FLAGS_DFS_OPERATIONS is set in the Flags field of the SMB2 > header, the file name includes a prefix that will be processed during > DFS name normalization as specified in section 3.3.5.9. Otherwise, the > file name is relative to the share that is identified by the TreeId in > the SMB2 header. Signed-off-by: Aurelien Aptel <aaptel@suse.com> Acked-by: Pavel Shilovsky <pshilov@microsoft.com> Signed-off-by: Steve French <smfrench@gmail.com>
2017-03-02sched/headers: Prepare to move signal wakeup & sigpending methods from ↵Ingo Molnar
<linux/sched.h> into <linux/sched/signal.h> Fix up affected files that include this signal functionality via sched.h. Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-03-02sched/headers: Prepare for new header dependencies before moving code to ↵Ingo Molnar
<linux/sched/signal.h> We are going to split <linux/sched/signal.h> out of <linux/sched.h>, which will have to be picked up from other headers and a couple of .c files. Create a trivial placeholder <linux/sched/signal.h> file that just maps to <linux/sched.h> to make this patch obviously correct and bisectable. Include the new header in the files that are going to need it. Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-03-01CIFS: set signing flag in SMB2+ TreeConnect if neededAurelien Aptel
cifs_enable_signing() already sets server->sign according to what the server requires/offers and what mount options allows/forbids, so use that. this is required for IPC tcon that connects to signing-required servers. Signed-off-by: Aurelien Aptel <aaptel@suse.com> Acked-by: Pavel Shilovsky <pshilov@microsoft.com> Signed-off-by: Steve French <smfrench@gmail.com>
2017-03-01CIFS: let ses->ipc_tid hold smb2 TreeIdsAurelien Aptel
the TreeId field went from 2 bytes in CIFS to 4 bytes in SMB2+. this commit updates the size of the ipc_tid field of a cifs_ses, which was still using 2 bytes. Signed-off-by: Aurelien Aptel <aaptel@suse.com> Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com> Signed-off-by: Steve French <smfrench@gmail.com>
2017-03-01CIFS: add use_ipc flag to SMB2_ioctl()Aurelien Aptel
when set, use the session IPC tree id instead of the tid in the provided tcon. Signed-off-by: Aurelien Aptel <aaptel@suse.com> Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com> Signed-off-by: Steve French <smfrench@gmail.com>
2017-03-01CIFS: add build_path_from_dentry_optional_prefix()Aurelien Aptel
this function does the same thing as add build_path_from_dentry() but takes a boolean parameter to decide whether or not to prefix the path with the tree name. we cannot rely on tcon->Flags & SMB_SHARE_IS_IN_DFS for SMB2 as smb2 code never sets tcon->Flags but it sets tcon->share_flags and it seems the SMB_SHARE_IS_IN_DFS has different semantics in SMB2: the prefix shouldn't be added everytime it was in SMB1. Signed-off-by: Aurelien Aptel <aaptel@suse.com> Acked-by: Pavel Shilovsky <pshilov@microsoft.com> Signed-off-by: Steve French <smfrench@gmail.com>
2017-03-01CIFS: move DFS response parsing out of SMB1 codeAurelien Aptel
since the DFS payload is not tied to the SMB version we can: * isolate the DFS payload in its own struct, and include that struct in packet structs * move the function that parses the response to misc.c and make it work on the new DFS payload struct (add payload size and utf16 flag as a result). Signed-off-by: Aurelien Aptel <aaptel@suse.com> Acked-by: Pavel Shilovsky <pshilov@microsoft.com> Signed-off-by: Steve French <smfrench@gmail.com>
2017-03-02KEYS: Differentiate uses of rcu_dereference_key() and user_key_payload()David Howells
rcu_dereference_key() and user_key_payload() are currently being used in two different, incompatible ways: (1) As a wrapper to rcu_dereference() - when only the RCU read lock used to protect the key. (2) As a wrapper to rcu_dereference_protected() - when the key semaphor is used to protect the key and the may be being modified. Fix this by splitting both of the key wrappers to produce: (1) RCU accessors for keys when caller has the key semaphore locked: dereference_key_locked() user_key_payload_locked() (2) RCU accessors for keys when caller holds the RCU read lock: dereference_key_rcu() user_key_payload_rcu() This should fix following warning in the NFS idmapper =============================== [ INFO: suspicious RCU usage. ] 4.10.0 #1 Tainted: G W ------------------------------- ./include/keys/user-type.h:53 suspicious rcu_dereference_protected() usage! other info that might help us debug this: rcu_scheduler_active = 2, debug_locks = 0 1 lock held by mount.nfs/5987: #0: (rcu_read_lock){......}, at: [<d000000002527abc>] nfs_idmap_get_key+0x15c/0x420 [nfsv4] stack backtrace: CPU: 1 PID: 5987 Comm: mount.nfs Tainted: G W 4.10.0 #1 Call Trace: dump_stack+0xe8/0x154 (unreliable) lockdep_rcu_suspicious+0x140/0x190 nfs_idmap_get_key+0x380/0x420 [nfsv4] nfs_map_name_to_uid+0x2a0/0x3b0 [nfsv4] decode_getfattr_attrs+0xfac/0x16b0 [nfsv4] decode_getfattr_generic.constprop.106+0xbc/0x150 [nfsv4] nfs4_xdr_dec_lookup_root+0xac/0xb0 [nfsv4] rpcauth_unwrap_resp+0xe8/0x140 [sunrpc] call_decode+0x29c/0x910 [sunrpc] __rpc_execute+0x140/0x8f0 [sunrpc] rpc_run_task+0x170/0x200 [sunrpc] nfs4_call_sync_sequence+0x68/0xa0 [nfsv4] _nfs4_lookup_root.isra.44+0xd0/0xf0 [nfsv4] nfs4_lookup_root+0xe0/0x350 [nfsv4] nfs4_lookup_root_sec+0x70/0xa0 [nfsv4] nfs4_find_root_sec+0xc4/0x100 [nfsv4] nfs4_proc_get_rootfh+0x5c/0xf0 [nfsv4] nfs4_get_rootfh+0x6c/0x190 [nfsv4] nfs4_server_common_setup+0xc4/0x260 [nfsv4] nfs4_create_server+0x278/0x3c0 [nfsv4] nfs4_remote_mount+0x50/0xb0 [nfsv4] mount_fs+0x74/0x210 vfs_kern_mount+0x78/0x220 nfs_do_root_mount+0xb0/0x140 [nfsv4] nfs4_try_mount+0x60/0x100 [nfsv4] nfs_fs_mount+0x5ec/0xda0 [nfs] mount_fs+0x74/0x210 vfs_kern_mount+0x78/0x220 do_mount+0x254/0xf70 SyS_mount+0x94/0x100 system_call+0x38/0xe0 Reported-by: Jan Stancek <jstancek@redhat.com> Signed-off-by: David Howells <dhowells@redhat.com> Tested-by: Jan Stancek <jstancek@redhat.com> Signed-off-by: James Morris <james.l.morris@oracle.com>
2017-03-01CIFS: Fix possible use after free in demultiplex threadPavel Shilovsky
The recent changes that added SMB3 encryption support introduced a possible use after free in the demultiplex thread. When we process an encrypted packed we obtain a pointer to SMB session but do not obtain a reference. This can possibly lead to a situation when this session was freed before we copy a decryption key from there. Fix this by obtaining a copy of the key rather than a pointer to the session under a spinlock. Signed-off-by: Pavel Shilovsky <pshilov@microsoft.com> Signed-off-by: Steve French <smfrench@gmail.com>
2017-02-24mm, fs: reduce fault, page_mkwrite, and pfn_mkwrite to take only vmfDave Jiang
->fault(), ->page_mkwrite(), and ->pfn_mkwrite() calls do not need to take a vma and vmf parameter when the vma already resides in vmf. Remove the vma parameter to simplify things. [arnd@arndb.de: fix ARM build] Link: http://lkml.kernel.org/r/20170125223558.1451224-1-arnd@arndb.de Link: http://lkml.kernel.org/r/148521301778.19116.10840599906674778980.stgit@djiang5-desk3.ch.intel.com Signed-off-by: Dave Jiang <dave.jiang@intel.com> Signed-off-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com> Cc: Theodore Ts'o <tytso@mit.edu> Cc: Darrick J. Wong <darrick.wong@oracle.com> Cc: Matthew Wilcox <mawilcox@microsoft.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Jan Kara <jack@suse.com> Cc: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-02-23Merge branch 'for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace Pull namespace updates from Eric Biederman: "There is a lot here. A lot of these changes result in subtle user visible differences in kernel behavior. I don't expect anything will care but I will revert/fix things immediately if any regressions show up. From Seth Forshee there is a continuation of the work to make the vfs ready for unpriviled mounts. We had thought the previous changes prevented the creation of files outside of s_user_ns of a filesystem, but it turns we missed the O_CREAT path. Ooops. Pavel Tikhomirov and Oleg Nesterov worked together to fix a long standing bug in the implemenation of PR_SET_CHILD_SUBREAPER where only children that are forked after the prctl are considered and not children forked before the prctl. The only known user of this prctl systemd forks all children after the prctl. So no userspace regressions will occur. Holding earlier forked children to the same rules as later forked children creates a semantic that is sane enough to allow checkpoing of processes that use this feature. There is a long delayed change by Nikolay Borisov to limit inotify instances inside a user namespace. Michael Kerrisk extends the API for files used to maniuplate namespaces with two new trivial ioctls to allow discovery of the hierachy and properties of namespaces. Konstantin Khlebnikov with the help of Al Viro adds code that when a network namespace exits purges it's sysctl entries from the dcache. As in some circumstances this could use a lot of memory. Vivek Goyal fixed a bug with stacked filesystems where the permissions on the wrong inode were being checked. I continue previous work on ptracing across exec. Allowing a file to be setuid across exec while being ptraced if the tracer has enough credentials in the user namespace, and if the process has CAP_SETUID in it's own namespace. Proc files for setuid or otherwise undumpable executables are now owned by the root in the user namespace of their mm. Allowing debugging of setuid applications in containers to work better. A bug I introduced with permission checking and automount is now fixed. The big change is to mark the mounts that the kernel initiates as a result of an automount. This allows the permission checks in sget to be safely suppressed for this kind of mount. As the permission check happened when the original filesystem was mounted. Finally a special case in the mount namespace is removed preventing unbounded chains in the mount hash table, and making the semantics simpler which benefits CRIU. The vfs fix along with related work in ima and evm I believe makes us ready to finish developing and merge fully unprivileged mounts of the fuse filesystem. The cleanups of the mount namespace makes discussing how to fix the worst case complexity of umount. The stacked filesystem fixes pave the way for adding multiple mappings for the filesystem uids so that efficient and safer containers can be implemented" * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: proc/sysctl: Don't grab i_lock under sysctl_lock. vfs: Use upper filesystem inode in bprm_fill_uid() proc/sysctl: prune stale dentries during unregistering mnt: Tuck mounts under others instead of creating shadow/side mounts. prctl: propagate has_child_subreaper flag to every descendant introduce the walk_process_tree() helper nsfs: Add an ioctl() to return owner UID of a userns fs: Better permission checking for submounts exit: fix the setns() && PR_SET_CHILD_SUBREAPER interaction vfs: open() with O_CREAT should not create inodes with unknown ids nsfs: Add an ioctl() to return the namespace type proc: Better ownership of files for non-dumpable tasks in user namespaces exec: Remove LSM_UNSAFE_PTRACE_CAP exec: Test the ptracer's saved cred to see if the tracee can gain caps exec: Don't reset euid and egid when the tracee has CAP_SETUID inotify: Convert to using per-namespace limits
2017-02-01CIFS: Allow to switch on encryption with seal mount optionPavel Shilovsky
This allows users to inforce encryption for SMB3 shares if a server supports it. Signed-off-by: Pavel Shilovsky <pshilov@microsoft.com>
2017-02-01CIFS: Add capability to decrypt big read responsesPavel Shilovsky
Allow to decrypt transformed packets that are bigger than the big buffer size. In particular it is used for read responses that can only exceed the big buffer size. Signed-off-by: Pavel Shilovsky <pshilov@microsoft.com>
2017-02-01CIFS: Decrypt and process small encrypted packetsPavel Shilovsky
Allow to decrypt transformed packets, find a corresponding mid and process as usual further. Signed-off-by: Pavel Shilovsky <pshilov@microsoft.com>
2017-02-01CIFS: Add copy into pages callback for a read operationPavel Shilovsky
Since we have two different types of reads (pagecache and direct) we need to process such responses differently after decryption of a packet. The change allows to specify a callback that copies a read payload data into preallocated pages. Signed-off-by: Pavel Shilovsky <pshilov@microsoft.com>
2017-02-01CIFS: Add mid handle callbackPavel Shilovsky
We need to process read responses differently because the data should go directly into preallocated pages. This can be done by specifying a mid handle callback. Signed-off-by: Pavel Shilovsky <pshilov@microsoft.com>
2017-02-01CIFS: Add transform header handling callbacksPavel Shilovsky
We need to recognize and parse transformed packets in demultiplex thread to find a corresponsing mid and process it further. Signed-off-by: Pavel Shilovsky <pshilov@microsoft.com>
2017-02-01CIFS: Encrypt SMB3 requests before sendingPavel Shilovsky
This change allows to encrypt packets if it is required by a server for SMB sessions or tree connections. Signed-off-by: Pavel Shilovsky <pshilov@microsoft.com>
2017-02-01CIFS: Enable encryption during session setup phasePavel Shilovsky
In order to allow encryption on SMB connection we need to exchange a session key and generate encryption and decryption keys. Signed-off-by: Pavel Shilovsky <pshilov@microsoft.com>
2017-02-01CIFS: Add capability to transform requests before sendingPavel Shilovsky
This will allow us to do protocol specific tranformations of packets before sending to the server. For SMB3 it can be used to support encryption. Signed-off-by: Pavel Shilovsky <pshilov@microsoft.com>
2017-02-01CIFS: Separate RFC1001 length processing for SMB2 readPavel Shilovsky
Allocate and initialize SMB2 read request without RFC1001 length field to directly call cifs_send_recv() rather than SendReceive2() in a read codepath. Signed-off-by: Pavel Shilovsky <pshilov@microsoft.com>
2017-02-01CIFS: Separate SMB2 sync header processingPavel Shilovsky
Do not process RFC1001 length in smb2_hdr_assemble() because it is not a part of SMB2 header. This allows to cleanup the code and adds a possibility combine several SMB2 packets into one for compounding. Signed-off-by: Pavel Shilovsky <pshilov@microsoft.com>
2017-02-01CIFS: Send RFC1001 length in a separate iovPavel Shilovsky
In order to simplify further encryption support we need to separate RFC1001 length and SMB2 header when sending a request. Put the length field in iov[0] and the rest of the packet into following iovs. Signed-off-by: Pavel Shilovsky <pshilov@microsoft.com>
2017-02-01CIFS: Make send_cancel take rqst as argumentPavel Shilovsky
Signed-off-by: Pavel Shilovsky <pshilov@microsoft.com>
2017-02-01CIFS: Make SendReceive2() takes resp iovPavel Shilovsky
Now SendReceive2 frees the first iov and returns a response buffer in it that increases a code complexity. Simplify this by making a caller responsible for freeing request buffer itself and returning a response buffer in a separate iov. Signed-off-by: Pavel Shilovsky <pshilov@microsoft.com>
2017-02-01CIFS: Separate SMB2 header structurePavel Shilovsky
In order to support compounding and encryption we need to separate RFC1001 length field and SMB2 header structure because the protocol treats them differently. This change will allow to simplify parsing of such complex SMB2 packets further. Signed-off-by: Pavel Shilovsky <pshilov@microsoft.com>
2017-02-01CIFS: Fix splice read for non-cached filesPavel Shilovsky
Currently we call copy_page_to_iter() for uncached reading into a pipe. This is wrong because it treats pages as VFS cache pages and copies references rather than actual data. When we are trying to read from the pipe we end up calling page_cache_pipe_buf_confirm() which returns -ENODATA. This error is translated into 0 which is returned to a user. This issue is reproduced by running xfs-tests suite (generic test #249) against mount points with "cache=none". Fix it by mapping pages manually and calling copy_to_iter() that copies data into the pipe. Cc: Stable <stable@vger.kernel.org> Signed-off-by: Pavel Shilovsky <pshilov@microsoft.com>
2017-02-01cifs: Add soft dependenciesJean Delvare
List soft dependencies of cifs so that mkinitrd and dracut can include the required helper modules. Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com> Signed-off-by: Jean Delvare <jdelvare@suse.de> Cc: Steve French <sfrench@samba.org>
2017-02-01cifs: Only select the required crypto modulesJean Delvare
The sha256 and cmac crypto modules are only needed for SMB2+, so move the select statements to config CIFS_SMB2. Also select CRYPTO_AES there as SMB2+ needs it. Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com> Signed-off-by: Jean Delvare <jdelvare@suse.de> Cc: Steve French <sfrench@samba.org>
2017-02-01cifs: Simplify SMB2 and SMB311 dependenciesJean Delvare
* CIFS_SMB2 depends on CIFS, which depends on INET and selects NLS. So these dependencies do not need to be repeated for CIFS_SMB2. * CIFS_SMB311 depends on CIFS_SMB2, which depends on INET. So this dependency doesn't need to be repeated for CIFS_SMB311. Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com> Signed-off-by: Jean Delvare <jdelvare@suse.de> Cc: Steve French <sfrench@samba.org>
2017-02-02fs: Better permission checking for submountsEric W. Biederman
To support unprivileged users mounting filesystems two permission checks have to be performed: a test to see if the user allowed to create a mount in the mount namespace, and a test to see if the user is allowed to access the specified filesystem. The automount case is special in that mounting the original filesystem grants permission to mount the sub-filesystems, to any user who happens to stumble across the their mountpoint and satisfies the ordinary filesystem permission checks. Attempting to handle the automount case by using override_creds almost works. It preserves the idea that permission to mount the original filesystem is permission to mount the sub-filesystem. Unfortunately using override_creds messes up the filesystems ordinary permission checks. Solve this by being explicit that a mount is a submount by introducing vfs_submount, and using it where appropriate. vfs_submount uses a new mount internal mount flags MS_SUBMOUNT, to let sget and friends know that a mount is a submount so they can take appropriate action. sget and sget_userns are modified to not perform any permission checks on submounts. follow_automount is modified to stop using override_creds as that has proven problemantic. do_mount is modified to always remove the new MS_SUBMOUNT flag so that we know userspace will never by able to specify it. autofs4 is modified to stop using current_real_cred that was put in there to handle the previous version of submount permission checking. cifs is modified to pass the mountpoint all of the way down to vfs_submount. debugfs is modified to pass the mountpoint all of the way down to trace_automount by adding a new parameter. To make this change easier a new typedef debugfs_automount_t is introduced to capture the type of the debugfs automount function. Cc: stable@vger.kernel.org Fixes: 069d5ac9ae0d ("autofs: Fix automounts by using current_real_cred()->uid") Fixes: aeaa4a79ff6a ("fs: Call d_automount with the filesystems creds") Reviewed-by: Trond Myklebust <trond.myklebust@primarydata.com> Reviewed-by: Seth Forshee <seth.forshee@canonical.com> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2017-01-14cifs: initialize file_info_lockRabin Vincent
Reviewed-by: Jeff Layton <jlayton@redhat.com> CC: Stable <stable@vger.kernel.org> file_info_lock is not initalized in initiate_cifs_search(), leading to the following splat after a simple "mount.cifs ... dir && ls dir/": BUG: spinlock bad magic on CPU#0, ls/486 lock: 0xffff880009301110, .magic: 00000000, .owner: <none>/-1, .owner_cpu: 0 CPU: 0 PID: 486 Comm: ls Not tainted 4.9.0 #27 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996) ffffc900042f3db0 ffffffff81327533 0000000000000000 ffff880009301110 ffffc900042f3dd0 ffffffff810baf75 ffff880009301110 ffffffff817ae077 ffffc900042f3df0 ffffffff810baff6 ffff880009301110 ffff880008d69900 Call Trace: [<ffffffff81327533>] dump_stack+0x65/0x92 [<ffffffff810baf75>] spin_dump+0x85/0xe0 [<ffffffff810baff6>] spin_bug+0x26/0x30 [<ffffffff810bb159>] do_raw_spin_lock+0xe9/0x130 [<ffffffff8159ad2f>] _raw_spin_lock+0x1f/0x30 [<ffffffff8127e50d>] cifs_closedir+0x4d/0x100 [<ffffffff81181cfd>] __fput+0x5d/0x160 [<ffffffff81181e3e>] ____fput+0xe/0x10 [<ffffffff8109410e>] task_work_run+0x7e/0xa0 [<ffffffff81002512>] exit_to_usermode_loop+0x92/0xa0 [<ffffffff810026f9>] syscall_return_slowpath+0x49/0x50 [<ffffffff8159b484>] entry_SYSCALL_64_fastpath+0xa7/0xa9 Fixes: 3afca265b5f53a0 ("Clarify locking of cifs file and tcon structures and make more granular") Signed-off-by: Rabin Vincent <rabinv@axis.com> Signed-off-by: Steve French <smfrench@gmail.com>
2016-12-24Replace <asm/uaccess.h> with <linux/uaccess.h> globallyLinus Torvalds
This was entirely automated, using the script by Al: PATT='^[[:blank:]]*#[[:blank:]]*include[[:blank:]]*<asm/uaccess.h>' sed -i -e "s!$PATT!#include <linux/uaccess.h>!" \ $(git grep -l "$PATT"|grep -v ^include/linux/uaccess.h) to do the replacement at the end of the merge window. Requested-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-12-24Merge branch 'for-next' of git://git.samba.org/sfrench/cifs-2.6Linus Torvalds
Pull cifs fixes from Steve French: "This ncludes various cifs/smb3 bug fixes, mostly for stable as well. In the next week I expect that Germano will have some reconnection fixes, and also I expect to have the remaining pieces of the snapshot enablement and SMB3 ACLs, but wanted to get this set of bug fixes in" * 'for-next' of git://git.samba.org/sfrench/cifs-2.6: cifs_get_root shouldn't use path with tree name Fix default behaviour for empty domains and add domainauto option cifs: use %16phN for formatting md5 sum cifs: Fix smbencrypt() to stop pointing a scatterlist at the stack CIFS: Fix a possible double locking of mutex during reconnect CIFS: Fix a possible memory corruption during reconnect CIFS: Fix a possible memory corruption in push locks CIFS: Fix missing nls unload in smb2_reconnect() CIFS: Decrease verbosity of ioctl call SMB3: parsing for new snapshot timestamp mount parm
2016-12-17Merge uncontroversial parts of branch 'readlink' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs Pull partial readlink cleanups from Miklos Szeredi. This is the uncontroversial part of the readlink cleanup patch-set that simplifies the default readlink handling. Miklos and Al are still discussing the rest of the series. * git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs: vfs: make generic_readlink() static vfs: remove ".readlink = generic_readlink" assignments vfs: default to generic_readlink() vfs: replace calling i_op->readlink with vfs_readlink() proc/self: use generic_readlink ecryptfs: use vfs_get_link() bad_inode: add missing i_op initializers
2016-12-15cifs_get_root shouldn't use path with tree nameSachin Prabhu
When a server returns the optional flag SMB_SHARE_IS_IN_DFS in response to a tree connect, cifs_build_path_to_root() will return a pathname which includes the hostname. This causes problems with cifs_get_root() which separates each component and does a lookup for each component of the path which in this case will incorrectly include looking up the hostname component as a path component. We encountered a problem with dfs shares hosted by a Netapp. When connecting to nodes pointed to by the DFS share. The tree connect for these nodes return SMB_SHARE_IS_IN_DFS resulting failures in lookup in cifs_get_root(). RH bz: 1373153 The patch was tested against a Netapp simulator and by a user using an actual Netapp server. Signed-off-by: Sachin Prabhu <sprabhu@redhat.com> Reported-by: Pierguido Lambri <plambri@redhat.com> Reviewed-by: Jeff Layton <jlayton@redhat.com> Signed-off-by: Steve French <smfrench@gmail.com>
2016-12-15Fix default behaviour for empty domains and add domainauto optionGermano Percossi
With commit 2b149f119 many things have been fixed/introduced. However, the default behaviour for RawNTLMSSP authentication seems to be wrong in case the domain is not passed on the command line. The main points (see below) of the patch are: - It alignes behaviour with Windows clients - It fixes backward compatibility - It fixes UPN I compared this behavour with the one from a Windows 10 command line client. When no domains are specified on the command line, I traced the packets and observed that the client does send an empty domain to the server. In the linux kernel case, the empty domain is replaced by the primary domain communicated by the SMB server. This means that, if the credentials are valid against the local server but that server is part of a domain, then the kernel module will ask to authenticate against that domain and we will get LOGON failure. I compared the packet trace from the smbclient when no domain is passed and, in that case, a default domain from the client smb.conf is taken. Apparently, connection succeeds anyway, because when the domain passed is not valid (in my case WORKGROUP), then the local one is tried and authentication succeeds. I tried with any kind of invalid domain and the result was always a connection. So, trying to interpret what to do and picking a valid domain if none is passed, seems the wrong thing to do. To this end, a new option "domainauto" has been added in case the user wants a mechanism for guessing. Without this patch, backward compatibility also is broken. With kernel 3.10, the default auth mechanism was NTLM. One of our testing servers accepted NTLM and, because no domains are passed, authentication was local. Moving to RawNTLMSSP forced us to change our command line to add a fake domain to pass to prevent this mechanism to kick in. For the same reasons, UPN is broken because the domain is specified in the username. The SMB server will work out the domain from the UPN and authenticate against the right server. Without the patch, though, given the domain is empty, it gets replaced with another domain that could be the wrong one for the authentication. Signed-off-by: Germano Percossi <germano.percossi@citrix.com> Acked-by: Pavel Shilovsky <pshilov@microsoft.com> Signed-off-by: Steve French <smfrench@gmail.com>
2016-12-15cifs: use %16phN for formatting md5 sumRasmus Villemoes
Passing a gazillion arguments takes a lot of code: add/remove: 0/0 grow/shrink: 0/2 up/down: 0/-253 (-253) Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk> Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com> Signed-off-by: Steve French <smfrench@gmail.com>
2016-12-14cifs: Fix smbencrypt() to stop pointing a scatterlist at the stackAndy Lutomirski
smbencrypt() points a scatterlist to the stack, which is breaks if CONFIG_VMAP_STACK=y. Fix it by switching to crypto_cipher_encrypt_one(). The new code should be considerably faster as an added benefit. This code is nearly identical to some code that Eric Biggers suggested. Cc: stable@vger.kernel.org # 4.9 only Reported-by: Eric Biggers <ebiggers3@gmail.com> Signed-off-by: Andy Lutomirski <luto@kernel.org> Acked-by: Jeff Layton <jlayton@redhat.com> Signed-off-by: Steve French <smfrench@gmail.com>
2016-12-13Merge branch 'for-4.10/block' of git://git.kernel.dk/linux-blockLinus Torvalds
Pull block layer updates from Jens Axboe: "This is the main block pull request this series. Contrary to previous release, I've kept the core and driver changes in the same branch. We always ended up having dependencies between the two for obvious reasons, so makes more sense to keep them together. That said, I'll probably try and keep more topical branches going forward, especially for cycles that end up being as busy as this one. The major parts of this pull request is: - Improved support for O_DIRECT on block devices, with a small private implementation instead of using the pig that is fs/direct-io.c. From Christoph. - Request completion tracking in a scalable fashion. This is utilized by two components in this pull, the new hybrid polling and the writeback queue throttling code. - Improved support for polling with O_DIRECT, adding a hybrid mode that combines pure polling with an initial sleep. From me. - Support for automatic throttling of writeback queues on the block side. This uses feedback from the device completion latencies to scale the queue on the block side up or down. From me. - Support from SMR drives in the block layer and for SD. From Hannes and Shaun. - Multi-connection support for nbd. From Josef. - Cleanup of request and bio flags, so we have a clear split between which are bio (or rq) private, and which ones are shared. From Christoph. - A set of patches from Bart, that improve how we handle queue stopping and starting in blk-mq. - Support for WRITE_ZEROES from Chaitanya. - Lightnvm updates from Javier/Matias. - Supoort for FC for the nvme-over-fabrics code. From James Smart. - A bunch of fixes from a whole slew of people, too many to name here" * 'for-4.10/block' of git://git.kernel.dk/linux-block: (182 commits) blk-stat: fix a few cases of missing batch flushing blk-flush: run the queue when inserting blk-mq flush elevator: make the rqhash helpers exported blk-mq: abstract out blk_mq_dispatch_rq_list() helper blk-mq: add blk_mq_start_stopped_hw_queue() block: improve handling of the magic discard payload blk-wbt: don't throttle discard or write zeroes nbd: use dev_err_ratelimited in io path nbd: reset the setup task for NBD_CLEAR_SOCK nvme-fabrics: Add FC LLDD loopback driver to test FC-NVME nvme-fabrics: Add target support for FC transport nvme-fabrics: Add host support for FC transport nvme-fabrics: Add FC transport LLDD api definitions nvme-fabrics: Add FC transport FC-NVME definitions nvme-fabrics: Add FC transport error codes to nvme.h Add type 0x28 NVME type code to scsi fc headers nvme-fabrics: patch target code in prep for FC transport support nvme-fabrics: set sqe.command_id in core not transports parser: add u64 number parser nvme-rdma: align to generic ib_event logging helper ...
2016-12-09vfs: remove ".readlink = generic_readlink" assignmentsMiklos Szeredi
If .readlink == NULL implies generic_readlink(). Generated by: to_del="\.readlink.*=.*generic_readlink" for i in `git grep -l $to_del`; do sed -i "/$to_del"/d $i; done Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2016-12-05CIFS: Fix a possible double locking of mutex during reconnectPavel Shilovsky
With the current code it is possible to lock a mutex twice when a subsequent reconnects are triggered. On the 1st reconnect we reconnect sessions and tcons and then persistent file handles. If the 2nd reconnect happens during the reconnecting of persistent file handles then the following sequence of calls is observed: cifs_reopen_file -> SMB2_open -> small_smb2_init -> smb2_reconnect -> cifs_reopen_persistent_file_handles -> cifs_reopen_file (again!). So, we are trying to acquire the same cfile->fh_mutex twice which is wrong. Fix this by moving reconnecting of persistent handles to the delayed work (smb2_reconnect_server) and submitting this work every time we reconnect tcon in SMB2 commands handling codepath. This can also lead to corruption of a temporary file list in cifs_reopen_persistent_file_handles() because we can recursively call this function twice. Cc: Stable <stable@vger.kernel.org> # v4.9+ Signed-off-by: Pavel Shilovsky <pshilov@microsoft.com>