[ Upstream commit 1c8951963d8ed357f70f59e0ad4ddce2199d2016 ]

The SMB2 open lookup is rooted at the share with LOOKUP_BENEATH, but the
create/mkdir/hardlink sink is not: ksmbd_vfs_kern_path_create() builds an
absolute path with convert_to_unix_name() and resolves it from AT_FDCWD
via start_creating_path(), so a ".." component is walked from the real
filesystem root and escapes the export.

An authenticated client races a missing path component so the rooted open
lookup returns -ENOENT (taking the create branch) while the same component
is present (a directory) when the create walk runs; the create then
resolves ".." out of the share.

Root the create walk at the share like the lookup and rename paths already
are: resolve the parent with vfs_path_parent_lookup(..., LOOKUP_BENEATH,
&share_conf->vfs_path) and create the final component with
start_creating_noperm(). convert_to_unix_name() then has no callers and is
removed.

Fixes: 265fd1991c1d ("ksmbd: use LOOKUP_BENEATH to prevent the out of share access")
Cc: stable@vger.kernel.org
Signed-off-by: Davide Ornaghi <d.ornaghi97@gmail.com>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

This patch introduces a /proc filesystem interface to ksmbd, providing
visibility into the internal state of the SMB server. This allows
administrators and developers to monitor active connections, user
sessions, and opened files in real-time without relying on external
tools or heavy debugging.

Key changes include:
 - Connection Monitoring (/proc/fs/ksmbd/clients): Displays a list of
   active network connections, including client IP addresses, SMB dialects,
   credits, and last active timestamps.

 - Session Management (/proc/fs/ksmbd/sessions/): Adds a global sessions
   file to list all authenticated users and their session IDs.

 - Creates individual session entries (e.g., /proc/fs/ksmbd/sessions/<id>)
   detailing capabilities (DFS, Multi-channel, etc.), signing/encryption
   algorithms, and connected tree shares.

 - File Tracking (/proc/fs/ksmbd/files): Shows all currently opened files
   across the server, including tree IDs, process IDs (PID), access modes
   (daccess/saccess), and oplock/lease states.

 - Statistics & Counters: Implements internal counters for global server
   metrics, such as the number of tree connections, total sessions, and
   processed read/write bytes.

Signed-off-by: Hyunchul Lee <hyc.lee@gmail.com>
Signed-off-by: Bahubali B Gumaji <bahubali.bg@samsung.com>
Signed-off-by: Sang-Soo Lee  <constant.lee@samsung.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
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>