Some servers (see MS-SMB2 protocol specification
section 3.3.5.15.1) expect that the FSCTL enumerate snapshots
is done twice, with the first query having EXACTLY the minimum
size response buffer requested (16 bytes) which refreshes
the snapshot list (otherwise that and subsequent queries get
an empty list returned).  So had to add code to set
the maximum response size differently for the first snapshot
query (which gets the size needed for the second query which
contains the actual list of snapshots).
Signed-off-by: NSteve French <stfrench@microsoft.com>
Reviewed-by: NRonnie Sahlberg <lsahlber@redhat.com>
Reviewed-by: NPavel Shilovsky <pshilov@microsoft.com>
CC: Stable <stable@vger.kernel.org> # 4.19+

Workaround problem with Samba responses to SMB3.1.1
null user (guest) mounts.  The server doesn't set the
expected flag in the session setup response so we have
to do a similar check to what is done in smb3_validate_negotiate
where we also check if the user is a null user (but not sec=krb5
since username might not be passed in on mount for Kerberos case).

Note that the commit below tightened the conditions and forced signing
for the SMB2-TreeConnect commands as per MS-SMB2.
However, this should only apply to normal user sessions and not for
cases where there is no user (even if server forgets to set the flag
in the response) since we don't have anything useful to sign with.
This is especially important now that the more secure SMB3.1.1 protocol
is in the default dialect list.

An earlier patch ("cifs: allow guest mounts to work for smb3.11") fixed
the guest mounts to Windows.

    Fixes: 6188f28b ("Tree connect for SMB3.1.1 must be signed for non-encrypted shares")
Reviewed-by: NRonnie Sahlberg <lsahlber@redhat.com>
Reviewed-by: NPaulo Alcantara <palcantara@suse.de>
CC: Stable <stable@vger.kernel.org>
Signed-off-by: NSteve French <stfrench@microsoft.com>

Fix Guest/Anonymous sessions so that they work with SMB 3.11.

The commit noted below tightened the conditions and forced signing for
the SMB2-TreeConnect commands as per MS-SMB2.
However, this should only apply to normal user sessions and not for
Guest/Anonumous sessions.

Fixes: 6188f28b ("Tree connect for SMB3.1.1 must be signed for non-encrypted shares")
Signed-off-by: NRonnie Sahlberg <lsahlber@redhat.com>
CC: Stable <stable@vger.kernel.org>
Signed-off-by: NSteve French <stfrench@microsoft.com>

This allows fallocate -z to work against a Windows2016 share.

This is due to the SMB3 ZERO_RANGE command does not modify the filesize.
To address this we will now append a compounded SET-INFO to update the
end-of-file information.

This brings xfstests generic/469 closer to working against a windows share.
Signed-off-by: NRonnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: NSteve French <stfrench@microsoft.com>

Define an _init() and a _free() function for SMB2_init so that we will
be able to use it with compounds.
Signed-off-by: NRonnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: NSteve French <stfrench@microsoft.com>

When we open the shared root handle also ask for FILE_ALL_INFORMATION since
we can do this at zero cost as part of a compound.
Cache this information as long as the lease is held and return and serve any
future requests from cache.

This allows us to serve "stat /<mountpoint>" directly from cache and avoid
a network roundtrip.  Since clients often want to do this quite a lot
this improve performance slightly.

As an example: xfstest generic/533 performs 43 stat operations on the root
of the share while it is run. Which are eliminated with this patch.
Signed-off-by: NRonnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: NSteve French <stfrench@microsoft.com>
Reviewed-by: NPavel Shilovsky <pshilov@microsoft.com>

We can end up building up credits too slowly to do large operations
(reads and writes for example) that require many credits. By
comparison most other SMB3 clients request many more (sometimes
thousands) of credits on all operations.  Increase
the number of credits we request on typical (non-large e.g
read/write) operations to 10 from 2 so we can build a pool of credits
faster.
Signed-off-by: NSteve French <stfrench@microsoft.com>
Reviewed-by: NRonnie Sahlberg <lsahlber@redhat.com>

Adds dynamic trace points for the query_info_enter
and query_info_done (no error) case.  We only had one
existing trace point related to this which was on query_info
errors.  Note that these two new tracepoints are for the
non-compounded query_info paths.

Sample output (from: trace-cmd record -e smb3_query_info*)

          ls-24140 [001] .... 27811.866068: smb3_query_info_enter: xid=7 sid=0xd2d00587 tid=0xb5441939 fid=0xcf082bac class=18 type=0x1
          ls-24140 [001] .... 27811.867656: smb3_query_info_done: xid=7 sid=0xd2d00587 tid=0xb5441939 fid=0xcf082bac class=18 type=0x1
  getcifsacl-24149 [005] .... 27854.759873: smb3_query_info_enter: xid=15 sid=0xd2d00587 tid=0xb5441939 fid=0x99896e72 class=0 type=0x3
  getcifsacl-24149 [005] .... 27854.761730: smb3_query_info_done: xid=15 sid=0xd2d00587 tid=0xb5441939 fid=0x99896e72 class=0 type=0x3
Signed-off-by: NSteve French <stfrench@microsoft.com>
Reviewed-by: NPavel Shilovsky <pshilov@microsoft.com>

Add dynamic trace point for open_enter (and posix mkdir enter)
Signed-off-by: NSteve French <stfrench@microsoft.com>
Reviewed-by: NPavel Shilovsky <pshilov@microsoft.com>

When ENODATA returned we weren't logging the read completion
(not an error, but can be indicated by logging length 0) which
makes looking at read traces confusing for smb3.
Signed-off-by: NSteve French <stfrench@microsoft.com>
Reviewed-by: NRonnie Sahlberg <lsahlber@redhat.com>

Allows tracing begin (not just completion) of read, write
and query_dir which may be helpful in finding slow requests
and other timing information
Signed-off-by: NSteve French <stfrench@microsoft.com>
Reviewed-by: NPavel Shilovsky <pshilov@microsoft.com>
Reviewed-by: NRonnie Sahlberg <lsahlber@redhat.com>

Adds two tracepoints - one for query_dir done (no err) and one for query_dir_err

Sanple output:

To start the trace in one window:
       trace-cmd record -e smb3_query_dir*

Then in another window after doing an
       ls /mnt

View the trace output by:

        trace-cmd show

Sample output:

           TASK-PID   CPU#  ||||    TIMESTAMP  FUNCTION
              | |       |   ||||       |         |
             ls-24869 [007] .... 90695.452009: smb3_query_dir_done: xid=7 sid=0x5027d24d tid=0xb95cf25a fid=0xc41a8c3e offset=0x0 len=0x16
             ls-24869 [000] .... 90695.452764: smb3_query_dir_done: xid=8 sid=0x5027d24d tid=0xb95cf25a fid=0xc41a8c3e offset=0x0 len=0x0
             ls-24874 [003] .... 90701.506342: smb3_query_dir_done: xid=11 sid=0x5027d24d tid=0xb95cf25a fid=0x33ad3601 offset=0x0 len=0x8
             ls-24874 [003] .... 90701.506917: smb3_query_dir_done: xid=12 sid=0x5027d24d tid=0xb95cf25a fid=0x33ad3601 offset=0x0 len=0x0
Reviewed-by: NPavel Shilovsky <pshilov@microsoft.com>
Reviewed-by: NRonnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: NSteve French <stfrench@microsoft.com>

POSIX negotiate context now includes the GUID specifying
which POSIX open context we support.
Signed-off-by: NSteve French <stfrench@microsoft.com>
Reviewed-by: NJeremy Allison <jra@samba.org>

Currently we do proper accounting for credits in regards to
reconnects and error handling, thus we do not need custom
credit adjustments when reconnect is detected developed
previously.
Signed-off-by: NPavel Shilovsky <pshilov@microsoft.com>
Signed-off-by: NSteve French <stfrench@microsoft.com>

Currently we adjust MTU credits before sending an IO request
and after reopening a file. This approach doesn't allow the
reopen routine to use existing credits that are not needed
for IO. Reorder credit adjustment and reopening a file to
use credits available to the client more efficiently. Also
unwrap complex if statement into few pieces to improve
readability.
Signed-off-by: NPavel Shilovsky <pshilov@microsoft.com>
Signed-off-by: NSteve French <stfrench@microsoft.com>

The reconnect might have happended after we obtained credits
and before we acquired srv_mutex. Check for that under the mutex
and retry an async operation if the reconnect is detected.
Signed-off-by: NPavel Shilovsky <pshilov@microsoft.com>
Signed-off-by: NSteve French <stfrench@microsoft.com>

Every time after a session reconnect we don't need to account for
credits obtained in previous sessions. Make use of the recently
added cifs_credits structure to properly calculate credits for
non-MTU requests the same way we did for MTU ones.
Signed-off-by: NPavel Shilovsky <pshilov@microsoft.com>
Signed-off-by: NSteve French <stfrench@microsoft.com>

Every time after a session reconnect we don't need to account for
credits obtained in previous sessions. Introduce new struct cifs_credits
which contains both credits value and reconnect instance of the
time those credits were taken. Modify a routine that add credits
back to handle the reconnect instance by assuming zero credits
if the reconnect happened after the credits were obtained and
before we decided to add them back due to some errors during sending.

This patch fixes the MTU credits cases. The subsequent patch
will handle non-MTU ones.
Signed-off-by: NPavel Shilovsky <pshilov@microsoft.com>
Signed-off-by: NSteve French <stfrench@microsoft.com>

Currently we skip setting a read error to -EIO if a stored
result is -ENODATA and a response hasn't been received. With
the recent changes in read error processing there shouldn't be
cases when -ENODATA is set without a response from the server,
so reset the error to -EIO unconditionally.
Signed-off-by: NPavel Shilovsky <pshilov@microsoft.com>
Signed-off-by: NSteve French <stfrench@microsoft.com>

Old windows version or Netapp SMB server will return
NT_STATUS_NOT_SUPPORTED since they do not allow or implement
FSCTL_VALIDATE_NEGOTIATE_INFO. The client should accept the response
provided it's properly signed.

See
https://blogs.msdn.microsoft.com/openspecification/2012/06/28/smb3-secure-dialect-negotiation/

and

MS-SMB2 validate negotiate response processing:
https://msdn.microsoft.com/en-us/library/hh880630.aspx

Samba client had already handled it.
https://bugzilla.samba.org/attachment.cgi?id=13285&action=editSigned-off-by: NNamjae Jeon <linkinjeon@gmail.com>
Signed-off-by: NSteve French <stfrench@microsoft.com>

If we try large I/O (read or write) immediately after mount
we won't typically have enough credits because we only request
large amounts of credits on the first session setup.  So if
large I/O is attempted soon after mount we will typically only
have about 43 credits rather than 105 credits (with this patch)
available for the large i/o (which needs 64 credits minimum).

This patch requests more credits during tree connect, which
helps ensure that we have enough credits when mount completes
(between these requests and the first session setup) in order
 to start large I/O immediately after mount if needed.
Signed-off-by: NSteve French <stfrench@microsoft.com>
Reviewed-by: NPavel Shilovsky <pshilov@microsoft.com>

a trivial patch that replaces all use of snprintf with scnprintf.
scnprintf() is generally seen as a safer function to use than
snprintf for many use cases.

In our case, there is no actual difference between the two since we never
look at the return value. Thus we did not have any of the bugs that
scnprintf protects against and the patch does nothing.

However, for people reading our code it will be a receipt that we
have done our due dilligence and checked our code for this type of bugs.

See the presentation "Making C Less Dangerous In The Linux Kernel"
at this years LCA
Signed-off-by: NRonnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: NSteve French <stfrench@microsoft.com>

The request buffers are freed right before copying the pointers.
Use the func args instead which are identical and still valid.

Simple reproducer (requires KASAN enabled) on a cifs mount:

echo foo > foo ; tail -f foo & rm foo

Cc: <stable@vger.kernel.org> # 4.20
Fixes: 179e44d4 ("smb3: add tracepoint for sending lease break responses to server")
Signed-off-by: NAurelien Aptel <aaptel@suse.com>
Signed-off-by: NSteve French <stfrench@microsoft.com>
Reviewed-by: NPaulo Alcantara <palcantara@suse.de>

When doing reads beyound the end of a file the server returns
error STATUS_END_OF_FILE error which is mapped to -ENODATA.
Currently we report it as a failure which confuses read stats.
Change it to not consider -ENODATA as failure for stat purposes.
Signed-off-by: NPavel Shilovsky <pshilov@microsoft.com>
Signed-off-by: NSteve French <stfrench@microsoft.com>
CC: Stable <stable@vger.kernel.org>

Signed-off-by: NPavel Shilovsky <pshilov@microsoft.com>
Signed-off-by: NSteve French <stfrench@microsoft.com>
CC: Stable <stable@vger.kernel.org>

Currently we log success once we send an async IO request to
the server. Instead we need to analyse a response and then log
success or failure for a particular command. Also fix argument
list for read logging.

Cc: <stable@vger.kernel.org> # 4.18
Signed-off-by: NPavel Shilovsky <pshilov@microsoft.com>
Signed-off-by: NSteve French <stfrench@microsoft.com>

If we don't receive a response we can't assume that the server
granted one credit. Assume zero credits in such cases.
Signed-off-by: NPavel Shilovsky <pshilov@microsoft.com>
Reviewed-by: NRonnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: NSteve French <stfrench@microsoft.com>

The call to SMB2_queary_acl can allocate memory to pntsd and also
return a failure via a call to SMB2_query_acl (and then query_info).
This occurs when query_info allocates the structure and then in
query_info the call to smb2_validate_and_copy_iov fails. Currently the
failure just returns without kfree'ing pntsd hence causing a memory
leak.

Currently, *data is allocated if it's not already pointing to a buffer,
so it needs to be kfree'd only if was allocated in query_info, so the
fix adds an allocated flag to track this.  Also set *dlen to zero on
an error just to be safe since *data is kfree'd.

Also set errno to -ENOMEM if the allocation of *data fails.
Signed-off-by: NColin Ian King <colin.king@canonical.com>
Signed-off-by: NSteve French <stfrench@microsoft.com>
Reviewed-by: NDan Carpener <dan.carpenter@oracle.com>

This addresses some compile warnings that you can
see depending on configuration settings.
Signed-off-by: NAurelien Aptel <aaptel@suse.com>
Signed-off-by: NSteve French <stfrench@microsoft.com>

Currently for MTU requests we allocate maximum possible credits
in advance and then adjust them according to the request size.
While we were adjusting the number of credits belonging to the
server, we were skipping adjustment of credits belonging to the
request. This patch fixes it by setting request credits to
CreditCharge field value of SMB2 packet header.

Also ask 1 credit more for async read and write operations to
increase parallelism and match the behavior of other operations.
Signed-off-by: NPavel Shilovsky <pshilov@microsoft.com>
Signed-off-by: NSteve French <stfrench@microsoft.com>
CC: Stable <stable@vger.kernel.org>

SMB3.1.1 dialect has additional security (among other) features
and should be requested when mounting to modern servers so it
can be used if the server supports it.

Add SMB3.1.1 to the default list of dialects requested.
Signed-off-by: NSteve French <stfrench@microsoft.com>
Reviewed-by: NRonnie Sahlberg <lsahlber@redhat.com>

After a successful failover in cifs_reconnect(), the smb2_reconnect()
function will make sure to reconnect every tcon to new target server.

For SMB2+.
Signed-off-by: NPaulo Alcantara <palcantara@suse.de>
Signed-off-by: NAurelien Aptel <aaptel@suse.com>
Signed-off-by: NSteve French <stfrench@microsoft.com>

Fixes gcc '-Wunused-but-set-variable' warning:

fs/cifs/smb2pdu.c: In function 'smb311_posix_mkdir':
fs/cifs/smb2pdu.c:2040:26: warning:
 variable 'server' set but not used [-Wunused-but-set-variable]

fs/cifs/smb2pdu.c: In function 'build_qfs_info_req':
fs/cifs/smb2pdu.c:4067:26: warning:
 variable 'server' set but not used [-Wunused-but-set-variable]

The first 'server' never used since commit bea851b8 ("smb3: Fix mode on
mkdir on smb311 mounts")
And the second not used since commit 1fc6ad2f ("cifs: remove
header_preamble_size where it is always 0")
Signed-off-by: NYueHaibing <yuehaibing@huawei.com>
Signed-off-by: NSteve French <stfrench@microsoft.com>

Reducing the number of network roundtrips improves the performance
of query xattrs
Signed-off-by: NRonnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: NSteve French <stfrench@microsoft.com>

In order to debug complex problems it is often helpful to
have detailed information on the client and server view
of the open file information.  Add the ability for root to
view the list of smb3 open files and dump the persistent
handle and other info so that it can be more easily
correlated with server logs.

Sample output from "cat /proc/fs/cifs/open_files"

 # Version:1
 # Format:
 # <tree id> <persistent fid> <flags> <count> <pid> <uid> <filename> <mid>
 0x5 0x800000378 0x8000 1 7704 0 some-file 0x14
 0xcb903c0c 0x84412e67 0x8000 1 7754 1001 rofile 0x1a6d
 0xcb903c0c 0x9526b767 0x8000 1 7720 1000 file 0x1a5b
 0xcb903c0c 0x9ce41a21 0x8000 1 7715 0 smallfile 0xd67
Signed-off-by: NSteve French <stfrench@microsoft.com>
Reviewed-by: NRonnie Sahlberg <lsahlber@redhat.com>

In debugging certain scenarios, especially reconnect cases,
it can be helpful to have a dynamic trace point for the
result of tree connect.  See sample output below
from a reconnect event. The new event is 'smb3_tcon'

            TASK-PID   CPU#  ||||    TIMESTAMP  FUNCTION
               | |       |   ||||       |         |
           cifsd-6071  [001] ....  2659.897923: smb3_reconnect: server=localhost current_mid=0xa
     kworker/1:1-71    [001] ....  2666.026342: smb3_cmd_done: 	sid=0x0 tid=0x0 cmd=0 mid=0
     kworker/1:1-71    [001] ....  2666.026576: smb3_cmd_err: 	sid=0xc49e1787 tid=0x0 cmd=1 mid=1 status=0xc0000016 rc=-5
     kworker/1:1-71    [001] ....  2666.031677: smb3_cmd_done: 	sid=0xc49e1787 tid=0x0 cmd=1 mid=2
     kworker/1:1-71    [001] ....  2666.031921: smb3_cmd_done: 	sid=0xc49e1787 tid=0x6e78f05f cmd=3 mid=3
     kworker/1:1-71    [001] ....  2666.031923: smb3_tcon: xid=0 sid=0xc49e1787 tid=0x0 unc_name=\\localhost\test rc=0
     kworker/1:1-71    [001] ....  2666.032097: smb3_cmd_done: 	sid=0xc49e1787 tid=0x6e78f05f cmd=11 mid=4
     kworker/1:1-71    [001] ....  2666.032265: smb3_cmd_done: 	sid=0xc49e1787 tid=0x7912332f cmd=3 mid=5
     kworker/1:1-71    [001] ....  2666.032266: smb3_tcon: xid=0 sid=0xc49e1787 tid=0x0 unc_name=\\localhost\IPC$ rc=0
     kworker/1:1-71    [001] ....  2666.032386: smb3_cmd_done: 	sid=0xc49e1787 tid=0x7912332f cmd=11 mid=6
Signed-off-by: NSteve French <stfrench@microsoft.com>
Reviewed-by: NRonnie Sahlberg <lsahlber@redhat.com>

Change these free functions to allow passing NULL as the argument and
treat it as a no-op just like free(NULL) would.
Or, if rqst->rq_iov is NULL.

The second scenario could happen for smb2_queryfs() if the call
to SMB2_query_info_init() fails and we go to qfs_exit to clean up
and free all resources.
In that case we have not yet assigned rqst[2].rq_iov and thus
the rq_iov dereference in SMB2_close_free() will cause a NULL pointer
dereference.

Fixes:  1eb9fb52 ("cifs: create SMB2_open_init()/SMB2_open_free() helpers")
Signed-off-by: NRonnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: NSteve French <stfrench@microsoft.com>
Reviewed-by: NAurelien Aptel <aaptel@suse.com>
CC: Stable <stable@vger.kernel.org>

To allow better debugging (for example applications with
handle leaks, or complex reconnect scenarios) display the
number of open files (on the client) and number of open
server file handles for each tcon in /proc/fs/cifs/Stats.
Note that open files on server is one larger than local
due to handle caching (in this case of the root of
the share).  In this example there are two local
open files, and three (two file and one directory handle)
open on the server.

Sample output:

$ cat /proc/fs/cifs/Stats
Resources in use
CIFS Session: 1
Share (unique mount targets): 2
SMB Request/Response Buffer: 1 Pool size: 5
SMB Small Req/Resp Buffer: 1 Pool size: 30
Operations (MIDs): 0

0 session 0 share reconnects
Total vfs operations: 36 maximum at one time: 2

1) \\localhost\test
SMBs: 69
Bytes read: 27  Bytes written: 0
Open files: 2 total (local), 3 open on server
TreeConnects: 1 total 0 failed
TreeDisconnects: 0 total 0 failed
Creates: 19 total 0 failed
Closes: 16 total 0 failed
...
Signed-off-by: NSteve French <stfrench@microsoft.com>

This allows userspace tools to query the raw info levels for cifs files
and process the response in userspace.
In particular this is useful for many of those data where there is no
corresponding native data structure in linux.
For example querying the security descriptor for a file and extract the
SIDs.
Signed-off-by: NRonnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: NSteve French <stfrench@microsoft.com>

In some error conditions, resp_buftype can be passed uninitialised to
free_rsp_buf(), potentially resulting in a spurious debug message.
If resp_buftype randomly had the value 1 (CIFS_SMALL_BUFFER) then this
would log a debug message.
The rsp pointer is initialised to NULL so there is no other side-effect.

Detected by CoverityScan, CID 1438585 ("Uninitialized scalar variable")
Detected by CoverityScan, CID 1438667 ("Uninitialized scalar variable")
Detected by CoverityScan, CID 1438764 ("Uninitialized scalar variable")
Signed-off-by: NGarry McNulty <garrmcnu@gmail.com>
Signed-off-by: NSteve French <stfrench@microsoft.com>
Reviewed-by: NAurelien Aptel <aaptel@suse.com>