We now do a weighted selection of server interfaces when allocating
new channels. The weights are decided based on the speed advertised.
The fulfilled weight for an interface is a counter that is used to
track the interface selection. It should be reset back to zero once
all interfaces fulfilling their weight.
In cifs_chan_update_iface, this reset logic was missing. As a result
when the server interface list changes, the client may not be able
to find a new candidate for other channels after all interfaces have
been fulfilled.
Fixes: a6d8fb54a5 ("cifs: distribute channels across interfaces based on speed")
Cc: <stable@vger.kernel.org>
Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
When mounting a share with kerberos authentication with multichannel
support, share mounts correctly, but fails to create secondary
channels. This occurs because the hostname is not populated when
adding the channels. The hostname is necessary for the userspace
cifs.upcall program to retrieve the required credentials and pass
it back to kernel, without hostname secondary channels fails
establish.
Cc: stable@vger.kernel.org
Reviewed-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Bharath SM <bharathsm@microsoft.com>
Reported-by: xfuren <xfuren@gmail.com>
Link: https://bugzilla.samba.org/show_bug.cgi?id=15824
Signed-off-by: Steve French <stfrench@microsoft.com>
When the server interface info changes (more common in clustered
servers like Azure Files), the per-channel iface gets updated.
However, this did not update the corresponding dstaddr. As a result
these channels will still connect (or try connecting) to older addresses.
Fixes: b54034a73b ("cifs: during reconnect, update interface if necessary")
Cc: <stable@vger.kernel.org>
Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
[MS-CIFS] specification in section 2.2.4.53.1 where is described
SMB_COM_SESSION_SETUP_ANDX Request, for SessionKey field says:
The client MUST set this field to be equal to the SessionKey field in
the SMB_COM_NEGOTIATE Response for this SMB connection.
Linux SMB client currently set this field to zero. This is working fine
against Windows NT SMB servers thanks to [MS-CIFS] product behavior <94>:
Windows NT Server ignores the client's SessionKey.
For compatibility with [MS-CIFS], set this SessionKey field in Session
Setup Request to value retrieved from Negotiate response.
Signed-off-by: Pali Rohár <pali@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
SMB1 Session Setup NTLMSSP Request in non-UNICODE mode is similar to
UNICODE mode, just strings are encoded in ASCII and not in UTF-16.
With this change it is possible to setup SMB1 session with NTLM
authentication in non-UNICODE mode with Windows SMB server.
This change fixes mounting SMB1 servers with -o nounicode mount option
together with -o sec=ntlmssp mount option (which is the default sec=).
Signed-off-by: Pali Rohár <pali@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
Like in UNICODE mode, SMB1 Session Setup Kerberos Request contains oslm and
domain strings.
Extract common code into ascii_oslm_strings() and ascii_domain_string()
functions (similar to unicode variants) and use these functions in
non-UNICODE code path in sess_auth_kerberos().
Decision if non-UNICODE or UNICODE mode is used is based on the
SMBFLG2_UNICODE flag in Flags2 packed field, and not based on the
capabilities of server. Fix this check too.
Signed-off-by: Pali Rohár <pali@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
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>
In a multichannel setup, it was observed that a few fields were not being
copied over to the secondary channels, which impacted performance in cases
where these options were relevant but not properly synchronized. To address
this, this patch introduces copying the following parameters from the
primary channel to the secondary channels:
- min_offload
- compression.requested
- dfs_conn
- ignore_signature
- leaf_fullpath
- noblockcnt
- retrans
- sign
By copying these parameters, we ensure consistency across channels and
prevent performance degradation due to missing or outdated settings.
Cc: stable@vger.kernel.org
Signed-off-by: Aman <aman1@microsoft.com>
Reviewed-by: Paulo Alcantara (Red Hat) <pc@manguebit.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
For multichannel mounts, when a new channel is successfully opened
we currently log 'successfully opened new channel on iface: <>' as
cifs_dbg(VFS..) which is eventually translated into a pr_err log.
Marking these informational logs as error logs may lead to confusion
for users so they will now be logged as info logs instead.
Signed-off-by: Bharath SM <bharathsm@microsoft.com>
Reviewed-by: Paulo Alcantara (Red Hat) <pc@manguebit.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
There are now more servers which advertise support for IAKerb (passthrough
Kerberos authentication via proxy). IAKerb is a public extension industry
standard Kerberos protocol that allows a client without line-of-sight
to a Domain Controller to authenticate. There can be cases where we
would fail to mount if the server only advertises the OID for IAKerb
in SPNEGO/GSSAPI. Add code to allow us to still upcall to userspace
in these cases to obtain the Kerberos ticket.
Signed-off-by: Steve French <stfrench@microsoft.com>
The last use of is_server_using_iface() was removed in 2022 by
commit aa45dadd34 ("cifs: change iface_list from array to sorted linked
list")
Remove it.
Signed-off-by: Dr. David Alan Gilbert <linux@treblig.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
Remove hard-coded strings by using the str_yes_no() helper function.
Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev>
Signed-off-by: Steve French <stfrench@microsoft.com>
Since commit 8da33fd11c ("cifs: avoid deadlocks while updating iface")
cifs_chan_update_iface now takes the chan_lock itself, so update the
comment accordingly.
Reviewed-by: Enzo Matsumiya <ematsumiya@suse.de>
Signed-off-by: Marco Crivellari <marco.crivellari@suse.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
cifs_ses_find_chan() has been unused since commit
f486ef8e20 ("cifs: use the chans_need_reconnect bitmap for reconnect status")
cifs_read_page_from_socket() has been unused since commit
d08089f649 ("cifs: Change the I/O paths to use an iterator rather than a page list")
cifs_chan_in_reconnect() has been unused since commit
bc962159e8 ("cifs: avoid race conditions with parallel reconnects")
Remove them.
Signed-off-by: Dr. David Alan Gilbert <linux@treblig.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
The SHA-512 shash TFM is used only briefly during Session Setup stage,
when computing SMB 3.1.1 preauth hash.
There's no need to keep it allocated in servers' secmech the whole time,
so keep its lifetime inside smb311_update_preauth_hash().
This also makes smb311_crypto_shash_allocate() redundant, so expose
smb3_crypto_shash_allocate() and use that.
Signed-off-by: Enzo Matsumiya <ematsumiya@suse.de>
Signed-off-by: Steve French <stfrench@microsoft.com>
Several users have reported this log getting dumped too regularly to
kernel log. The likely root cause has been identified, and it suggests
that this situation is expected for some configurations
(for example SMB2.1).
Since the function returns appropriately even for such cases, it is
fairly harmless to make this a debug log. When needed, the verbosity
can be increased to capture this log.
Cc: stable@vger.kernel.org
Reported-by: Jan Čermák <sairon@sairon.cz>
Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Based on our implementation of multichannel, it is entirely
possible that a server struct may not be found in any channel
of an SMB session.
In such cases, we should be prepared to move on and search for
the server struct in the next session.
Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Address static checker warning in cifs_ses_get_chan_index():
warn: variable dereferenced before check 'server'
To be consistent, and reduce risk, we should add another check
for null server pointer.
Fixes: 88675b22d3 ("cifs: do not search for channel if server is terminating")
Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Reviewed-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
After the interface selection policy change to do a weighted
round robin, each iface maintains a weight_fulfilled. When the
weight_fulfilled reaches the total weight for the iface, we know
that the weights can be reset and ifaces can be allocated from
scratch again.
During channel allocation failures on a particular channel,
weight_fulfilled is not incremented. If a few interfaces are
inactive, we could end up in a situation where the active
interfaces are all allocated for the total_weight, and inactive
ones are all that remain. This can cause a situation where
no more channels can be allocated further.
This change fixes it by increasing weight_fulfilled, even when
channel allocation failure happens. This could mean that if
there are temporary failures in channel allocation, the iface
weights may not strictly be adhered to. But that's still okay.
Fixes: a6d8fb54a5 ("cifs: distribute channels across interfaces based on speed")
Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
In order to scale down the channels, the following sequence
of operations happen:
1. server struct is marked for terminate
2. the channel is deallocated in the ses->chans array
3. at a later point the cifsd thread actually terminates the server
Between 2 and 3, there can be calls to find the channel for
a server struct. When that happens, there can be an ugly warning
that's logged. But this is expected.
So this change does two things:
1. in cifs_ses_get_chan_index, if server->terminate is set, return
2. always make sure server->terminate is set with chan_lock held
Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Return statement was not needed at end of cifs_chan_update_iface
Suggested-by: Christophe Jaillet <christophe.jaillet@wanadoo.fr>
Signed-off-by: Steve French <stfrench@microsoft.com>
The return values for cifs_chan_update_iface() didn't match what the
documentation said and nothing was checking them anyway. Just make it
a void function.
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
We return early if "iface" is NULL so there is no need to check here.
Delete those checks.
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
Recently, cifs_chan_update_iface was modified to not
remove an iface if a suitable replacement was not found.
With that, there were two conditionals that were exactly
the same. This change removes that extra condition check.
Also, fixed a logging in the same function to indicate
the correct message.
Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
cifs_chan_update_iface is meant to check and update the server
interface used for a channel when the existing server interface
is no longer available.
So far, this handler had the code to remove an interface entry
even if a new candidate interface is not available. Allowing
this leads to several corner cases to handle.
This change makes the logic much simpler by not deallocating
the current channel interface entry if a new interface is not
found to replace it with.
Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
We were deferencing iface after it has been released. Fix is to
release after all dereference instances have been encountered.
Signed-off-by: Ritvik Budhiraja <rbudhiraja@microsoft.com>
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <error27@gmail.com>
Closes: https://lore.kernel.org/r/202311110815.UJaeU3Tt-lkp@intel.com/
Signed-off-by: Steve French <stfrench@microsoft.com>
The code to handle the case of server disabling multichannel
was picking iface_lock with chan_lock held. This goes against
the lock ordering rules, as iface_lock is a higher order lock
(even if it isn't so obvious).
This change fixes the lock ordering by doing the following in
that order for each secondary channel:
1. store iface and server pointers in local variable
2. remove references to iface and server in channels
3. unlock chan_lock
4. lock iface_lock
5. dec ref count for iface
6. unlock iface_lock
7. dec ref count for server
8. lock chan_lock again
Since this function can only be called in smb2_reconnect, and
that cannot be called by two parallel processes, we should not
have races due to dropping chan_lock between steps 3 and 8.
Fixes: ee1d21794e ("cifs: handle when server stops supporting multichannel")
Reported-by: Paulo Alcantara <pc@manguebit.com>
Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
When a server stops supporting multichannel, we will
keep attempting reconnects to the secondary channels today.
Avoid this by freeing extra channels when negotiate
returns no multichannel support.
Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Minor cleanup of style issues found by checkpatch
Reviewed-by: Bharath SM <bharathsm@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
The only reason why cifs_sb gets passed today to cifs_try_adding_channels
is to pass the local_nls field for the new channels and binding session.
However, the ses struct already has local_nls field that is setup during
the first cifs_setup_session. So there is no need to pass cifs_sb.
This change removes cifs_sb from the arg list for this and the functions
that it calls and uses ses->local_nls instead.
Cc: stable@vger.kernel.org
Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Reviewed-by: Paulo Alcantara (SUSE) <pc@manguebit.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
The refcounting of server interfaces should account
for the primary channel too. Although this is not
strictly necessary, doing so will account for the primary
channel in DebugData.
Cc: stable@vger.kernel.org
Reviewed-by: Paulo Alcantara (SUSE) <pc@manguebit.com>
Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Today, if the server interfaces RSS capable, we simply
choose the fastest interface to setup a channel. This is not
a scalable approach, and does not make a lot of attempt to
distribute the connections.
This change does a weighted distribution of channels across
all the available server interfaces, where the weight is
a function of the advertised interface speed.
Also make sure that we don't mix rdma and non-rdma for channels.
Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
So far, SMB multichannel could only scale up, but not
scale down the number of channels. In this series of
patch, we now allow the client to deal with the case
of multichannel disabled on the server when the share
is mounted. With that change, we now need the ability
to scale down the channels.
This change allows the client to deal with cases of
missing channels more gracefully.
Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
If the mount command has specified multichannel as a mount option,
but multichannel is found to be unsupported by the server at the time
of mount, we set chan_max to 1. Which means that the user needs to
remount the share if the server starts supporting multichannel.
This change removes this reset. What it means is that if the user
specified multichannel or max_channels during mount, and at this
time, multichannel is not supported, but the server starts supporting
it at a later point, the client will be capable of scaling out the
number of channels.
Cc: stable@vger.kernel.org
Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
The NTLM authenticate message currently sets the NTLMSSP_NEGOTIATE_VERSION
flag but does not populate the VERSION structure. This commit fixes this
bug by ensuring that the flag is set and the version details are included
in the message.
Signed-off-by: Meetakshi Setiya <msetiya@microsoft.com>
Reviewed-by: Bharath SM <bharathsm@microsoft.com>
Reviewed-by: Paulo Alcantara (SUSE) <pc@manguebit.com>
Reviewed-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Since older dialects such as CIFS do not support multichannel
the macro CIFS_SERVER_IS_CHAN can be confusing (it requires SMB 3
or later) so shorten its name to "SERVER_IS_CHAN"
Suggested-by: Tom Talpey <tom@talpey.com>
Acked-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Clang warns about exceeded stack frame size
fs/smb/client/sess.c:160:5: warning: stack frame size (1368) exceeds
limit (1024) in 'cifs_try_adding_channels' [-Wframe-larger-than]
It turns out that cifs_ses_add_channel() got inlined into
cifs_try_adding_channels() which had a stack-allocated variable @ctx
of 624 bytes in size. Fix this by making it heap-allocated.
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202307270640.5ODmPwDl-lkp@intel.com/
Signed-off-by: Paulo Alcantara (SUSE) <pc@manguebit.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
The NTLMSSP_NEGOTIATE_VERSION flag only needs to be sent during
the NTLMSSP NEGOTIATE (not the AUTH) request, so filter it out for
NTLMSSP AUTH requests. See MS-NLMP 2.2.1.3
This fixes a problem found by the gssntlmssp server.
Link: https://github.com/gssapi/gss-ntlmssp/issues/95
Fixes: 52d005337b ("smb3: send NTLMSSP version information")
Acked-by: Roy Shterman <roy.shterman@gmail.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
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>
