Currently, ksmbd does not verify if the user attempting to reconnect
to a durable handle is the same user who originally opened the file.
This allows any authenticated user to hijack an orphaned durable handle
by predicting or brute-forcing the persistent ID.
According to MS-SMB2, the server MUST verify that the SecurityContext
of the reconnect request matches the SecurityContext associated with
the existing open.
Add a durable_owner structure to ksmbd_file to store the original opener's
UID, GID, and account name. and catpure the owner information when a file
handle becomes orphaned. and implementing ksmbd_vfs_compare_durable_owner()
to validate the identity of the requester during SMB2_CREATE (DHnC).
Fixes: c8efcc7861 ("ksmbd: add support for durable handles v1/v2")
Reported-by: Davide Ornaghi <d.ornaghi97@gmail.com>
Reported-by: Navaneeth K <knavaneeth786@gmail.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
ksmbd currently frees oplock_info immediately using kfree(), even
though it is accessed under RCU read-side critical sections in places
like opinfo_get() and proc_show_files().
Since there is no RCU grace period delay between nullifying the pointer
and freeing the memory, a reader can still access oplock_info
structure after it has been freed. This can leads to a use-after-free
especially in opinfo_get() where atomic_inc_not_zero() is called on
already freed memory.
Fix this by switching to deferred freeing using call_rcu().
Fixes: 18b4fac5ef ("ksmbd: fix use-after-free in smb_break_all_levII_oplock()")
Cc: stable@vger.kernel.org
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
There is a room in smb_break_all_levII_oplock that can cause racy issues
when unlocking in the middle of the loop. This patch use read lock
to protect whole loop.
Cc: stable@vger.kernel.org
Reported-by: Norbert Szetei <norbert@doyensec.com>
Tested-by: Norbert Szetei <norbert@doyensec.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
->interim_entry of ksmbd_work could be deleted after oplock is freed.
We don't need to manage it with linked list. The interim request could be
immediately sent whenever a oplock break wait is needed.
Cc: stable@vger.kernel.org
Reported-by: Norbert Szetei <norbert@doyensec.com>
Tested-by: Norbert Szetei <norbert@doyensec.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
Durable file handles allow reopening a file preserved on a short
network outage and transparent client reconnection within a timeout.
i.e. Durable handles aren't necessarily cleaned up when the opening
process terminates.
This patch add support for durable handle version 1 and 2.
To prove durable handles work on ksmbd, I have tested this patch with
the following smbtorture tests:
smb2.durable-open.open-oplock
smb2.durable-open.open-lease
smb2.durable-open.reopen1
smb2.durable-open.reopen1a
smb2.durable-open.reopen1a-lease
smb2.durable-open.reopen2
smb2.durable-open.reopen2a
smb2.durable-open.reopen2-lease
smb2.durable-open.reopen2-lease-v2
smb2.durable-open.reopen3
smb2.durable-open.reopen4
smb2.durable-open.delete_on_close2
smb2.durable-open.file-position
smb2.durable-open.lease
smb2.durable-open.alloc-size
smb2.durable-open.read-only
smb2.durable-v2-open.create-blob
smb2.durable-v2-open.open-oplock
smb2.durable-v2-open.open-lease
smb2.durable-v2-open.reopen1
smb2.durable-v2-open.reopen1a
smb2.durable-v2-open.reopen1a-lease
smb2.durable-v2-open.reopen2
smb2.durable-v2-open.reopen2b
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
Don't immediately send directory lease break notification on smb2_write().
Instead, It postpones it until smb2_close().
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
If client send different parent key, different client guid, or there is
no parent lease key flags in create context v2 lease, ksmbd send lease
break to client.
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
RWH(Read + Write + Handle) caching state is not supported for directory.
ksmbd downgrade it to RH for directory if client send RWH caching lease
state.
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
To support v2 lease(directory lease), ksmbd set epoch in create context
v2 lease response.
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>
