smb: client: fix potential UAF in cifs_stats_proc_show()

Skip sessions that are being teared down (status == SES_EXITING) to
avoid UAF.

Cc: stable@vger.kernel.org
Signed-off-by: Paulo Alcantara (Red Hat) <pc@manguebit.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

smb: client: fix potential UAF in cifs_stats_proc_write()

Skip sessions that are being teared down (status == SES_EXITING) to
avoid UAF.

Cc: stable@vger.kernel.org
Signed-off-by: Paulo Alcantara (Red Hat) <pc@manguebit.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

smb: client: fix potential UAF in cifs_debug_files_proc_show()

Skip sessions that are being teared down (status == SES_EXITING) to
avoid UAF.

Cc: stable@vger.kernel.org
Signed-off-by: Paulo Alcantara (Red Hat) <pc@manguebit.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

smb: client: negotiate compression algorithms

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>

cifs: allow changing password during remount

There are cases where a session is disconnected and password has changed
on the server (or expired) for this user and this currently can not
be fixed without unmount and mounting again. This patch allows
remount to change the password (for the non Kerberos case, Kerberos
ticket refresh is handled differently) when the session is disconnected
and the user can not reconnect due to still using old password.

Future patches should also allow us to setup the keyring (cifscreds)
to have an "alternate password" so we would be able to change
the password before the session drops (without the risk of races
between when the password changes and the disconnect occurs -
ie cases where the old password is still needed because the new
password has not fully rolled out to all servers yet).

Cc: stable@vger.kernel.org
Signed-off-by: Steve French <stfrench@microsoft.com>

smb3: show beginning time for per share stats

In analyzing problems, one missing piece of debug data is when the
mount occurred. A related problem is when collecting stats we don't
know the period of time the stats covered, ie when this set of stats
for the tcon started to be collected. To make debugging easier track
the stats begin time. Set it when the mount occurred at mount time,
and reset it to current time whenever stats are reset. For example,

...
1) \\localhost\test
SMBs: 14 since 2024-01-17 22:17:30 UTC
Bytes read: 0 Bytes written: 0
Open files: 0 total (local), 0 open on server
TreeConnects: 1 total 0 failed
TreeDisconnects: 0 total 0 failed
...
2) \\localhost\scratch
SMBs: 24 since 2024-01-17 22:16:04 UTC
Bytes read: 0 Bytes written: 0
Open files: 0 total (local), 0 open on server
TreeConnects: 1 total 0 failed
TreeDisconnects: 0 total 0 failed
...

Note the time "since ... UTC" is now displayed in /proc/fs/cifs/Stats
for each share that is mounted.

Suggested-by: Shyam Prasad N <sprasad@microsoft.com>
Reviewed-by: Bharath SM <bharathsm@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

smb: client: fix potential OOB in cifs_dump_detail()

Validate SMB message with ->check_message() before calling
->calc_smb_size().

Signed-off-by: Paulo Alcantara (SUSE) <pc@manguebit.com>
Cc: stable@vger.kernel.org
Signed-off-by: Steve French <stfrench@microsoft.com>

cifs: distribute channels across interfaces based on speed

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>

cifs: handle cases where a channel is closed

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>

smb3: minor RDMA cleanup

Some minor smbdirect debug cleanup spotted by checkpatch

Cc: Long Li <longli@microsoft.com>
Reviewed-by: Bharath SM <bharathsm@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

cifs: print server capabilities in DebugData

In the output of /proc/fs/cifs/DebugData, we do not
print the server->capabilities field today.
With this change, we will do that.

Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

smb: client: fix use-after-free bug in cifs_debug_data_proc_show()

Skip SMB sessions that are being teared down
(e.g. @ses->ses_status == SES_EXITING) in cifs_debug_data_proc_show()
to avoid use-after-free in @ses.

This fixes the following GPF when reading from /proc/fs/cifs/DebugData
while mounting and umounting

[ 816.251274] general protection fault, probably for non-canonical
address 0x6b6b6b6b6b6b6d81: 0000 [#1] PREEMPT SMP NOPTI
...
[ 816.260138] Call Trace:
[ 816.260329] <TASK>
[ 816.260499] ? die_addr+0x36/0x90
[ 816.260762] ? exc_general_protection+0x1b3/0x410
[ 816.261126] ? asm_exc_general_protection+0x26/0x30
[ 816.261502] ? cifs_debug_tcon+0xbd/0x240 [cifs]
[ 816.261878] ? cifs_debug_tcon+0xab/0x240 [cifs]
[ 816.262249] cifs_debug_data_proc_show+0x516/0xdb0 [cifs]
[ 816.262689] ? seq_read_iter+0x379/0x470
[ 816.262995] seq_read_iter+0x118/0x470
[ 816.263291] proc_reg_read_iter+0x53/0x90
[ 816.263596] ? srso_alias_return_thunk+0x5/0x7f
[ 816.263945] vfs_read+0x201/0x350
[ 816.264211] ksys_read+0x75/0x100
[ 816.264472] do_syscall_64+0x3f/0x90
[ 816.264750] entry_SYSCALL_64_after_hwframe+0x6e/0xd8
[ 816.265135] RIP: 0033:0x7fd5e669d381

Cc: stable@vger.kernel.org
Signed-off-by: Paulo Alcantara (SUSE) <pc@manguebit.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

SMB3: rename macro CIFS_SERVER_IS_CHAN to avoid confusion

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>

smb3: display network namespace in debug information

We recently had problems where a network namespace was deleted
causing hard to debug reconnect problems. To help deal with
configuration issues like this it is useful to dump the network
namespace to better debug what happened.

So add this to information displayed in /proc/fs/cifs/DebugData for
the server (and channels if mounted with multichannel). For example:

Local Users To Server: 1 SecMode: 0x1 Req On Wire: 0 Net namespace: 4026531840

This can be easily compared with what is displayed for the
processes on the system. For example /proc/1/ns/net in this case
showed the same thing (see below), and we can see that the namespace
is still valid in this example.

'net:[4026531840]'

Cc: stable@vger.kernel.org
Acked-by: Paulo Alcantara (SUSE) <pc@manguebit.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

smb: client: fix shared DFS root mounts with different prefixes

When having two DFS root mounts that are connected to same namespace,
same mount options but different prefix paths, we can't really use the
shared @server->origin_fullpath when chasing DFS links in them.

Move the origin_fullpath field to cifs_tcon structure so when having
shared DFS root mounts with different prefix paths, and we need to
chase any DFS links, dfs_get_automount_devname() will pick up the
correct full path out of the @tcon that will be used for the new
mount.

Before patch

mount.cifs //dom/dfs/dir /mnt/1 -o ...
mount.cifs //dom/dfs /mnt/2 -o ...
# shared server, ses, tcon
# server: origin_fullpath=//dom/dfs/dir

# @server->origin_fullpath + '/dir/link1'
$ ls /mnt/2/dir/link1
ls: cannot open directory '/mnt/2/dir/link1': No such file or directory

After patch

mount.cifs //dom/dfs/dir /mnt/1 -o ...
mount.cifs //dom/dfs /mnt/2 -o ...
# shared server & ses
# tcon_1: origin_fullpath=//dom/dfs/dir
# tcon_2: origin_fullpath=//dom/dfs

# @tcon_2->origin_fullpath + '/dir/link1'
$ ls /mnt/2/dir/link1
dir0 dir1 dir10 dir3 dir5 dir6 dir7 dir9 target2_file.txt tsub

Fixes: 8e3554150d6c ("cifs: fix sharing of DFS connections")
Signed-off-by: Paulo Alcantara (SUSE) <pc@manguebit.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

cifs: print client_guid in DebugData

Having the ClientGUID info makes it easier to debug
issues related to a client on a server that serves a
number of clients.

This change prints the ClientGUID in DebugData.

Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Acked-by: Tom Talpey <tom@talpey.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

smb/client: print "Unknown" instead of bogus link speed value

The virtio driver for Linux guests will not set a link speed to its
paravirtualized NICs. This will be seen as -1 in the ethernet layer, and
when some servers (e.g. samba) fetches it, it's converted to an unsigned
value (and multiplied by 1000 * 1000), so in client side we end up with:

1) Speed: 4294967295000000 bps

in DebugData.

This patch introduces a helper that returns a speed string (in Mbps or
Gbps) if interface speed is valid (>= SPEED_10 and <= SPEED_800000), or
"Unknown" otherwise.

The reason to not change the value in iface->speed is because we don't
know the real speed of the HW backing the server NIC, so let's keep
considering these as the fastest NICs available.

Also print "Capabilities: None" when the interface doesn't support any.

Signed-off-by: Enzo Matsumiya <ematsumiya@suse.de>
Reviewed-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

cifs: print all credit counters in DebugData

Output of /proc/fs/cifs/DebugData shows only the per-connection
counter for the number of credits of regular type. i.e. the
credits reserved for echo and oplocks are not displayed.

There have been situations recently where having this info
would have been useful. This change prints the credit counters
of all three types: regular, echo, oplocks.

Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

smb: move client and server files to common directory fs/smb

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>