Commit Graph

1056 Commits

Author SHA1 Message Date
Christoph Hellwig
1b9474635e cifs: truncate fallout
Remove the calls to inode_newsize_ok given that we already did it as
part of inode_change_ok in the beginning of cifs_setattr_(no)unix.

No need to call ->truncate if cifs doesn't have one, so remove the
explicit call in cifs_vmtruncate, and replace the calls to vmtruncate
with truncate_setsize which is vmtruncate minus inode_newsize_ok
and the call to ->truncate.

Rename cifs_vmtruncate to cifs_setsize to match the new calling conventions.

Question 1:  why does cifs do the pagecache munging and i_size update twice
	for each setattr call, once opencoded in cifs_vmtruncate, and once
	using the VFS helpers?
Question 2: what is supposed to be protected by i_lock in cifs_vmtruncate?
	Do we need it around the call to inode_change_ok?

[AV: fixed build breakage]

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2010-08-09 16:48:48 -04:00
Al Viro
b57922d97f convert remaining ->clear_inode() to ->evict_inode()
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2010-08-09 16:48:37 -04:00
Al Viro
45321ac543 Make ->drop_inode() just return whether inode needs to be dropped
... and let iput_final() do the actual eviction or retention

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2010-08-09 16:48:35 -04:00
Christoph Hellwig
db78b877f7 always call inode_change_ok early in ->setattr
Make sure we call inode_change_ok before doing any changes in ->setattr,
and make sure to call it even if our fs wants to ignore normal UNIX
permissions, but use the ATTR_FORCE to skip those.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2010-08-09 16:47:38 -04:00
Christoph Hellwig
1025774ce4 remove inode_setattr
Replace inode_setattr with opencoded variants of it in all callers.  This
moves the remaining call to vmtruncate into the filesystem methods where it
can be replaced with the proper truncate sequence.

In a few cases it was obvious that we would never end up calling vmtruncate
so it was left out in the opencoded variant:

 spufs: explicitly checks for ATTR_SIZE earlier
 btrfs,hugetlbfs,logfs,dlmfs: explicitly clears ATTR_SIZE earlier
 ufs: contains an opencoded simple_seattr + truncate that sets the filesize just above

In addition to that ncpfs called inode_setattr with handcrafted iattrs,
which allowed to trim down the opencoded variant.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2010-08-09 16:47:37 -04:00
Jeff Layton
cb76d5e250 cifs: fsc should not default to "on"
I'm not sure why this was merged with this flag hardcoded on, but it
seems quite dangerous. Turn it off.

Also, mount.cifs hands unrecognized options off to the kernel so there
should be no need for changes there in order to support this.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
2010-08-02 12:40:41 +00:00
Steve French
f67909cf80 [CIFS] remove redundant path walking in dfs_do_refmount
Reviewed-by: Dave Howells <dhowells@redhat.com>
Signed-off-by: Igor Mammedov <niallain@gmail.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
2010-08-02 12:40:40 +00:00
Jeff Layton
f636a34802 cifs: ignore the "mand", "nomand" and "_netdev" mount options
These are all handled by the userspace mount programs, but older versions
of mount.cifs also handed them off to the kernel. Ignore them.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
2010-08-02 12:40:40 +00:00
Jeff Layton
3572d2857f cifs: map NT_STATUS_ERROR_WRITE_PROTECTED to -EROFS
Seems like a more sensible mapping than -EIO.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
2010-08-02 12:40:40 +00:00
Jeff Layton
f30b9c1184 cifs: don't allow cifs_iget to match inodes of the wrong type
If the type is different from what we think it should be, then don't
match the existing inode.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
2010-08-02 12:40:39 +00:00
Steve French
9f841593ff [CIFS] relinquish fscache cookie before freeing CIFSTconInfo
Doh, fix a use after free bug.

Signed-off-by: Suresh Jayaraman <sjayaraman@suse.de>
Reviewed-and-Tested-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
2010-08-02 12:40:39 +00:00
Jeff Layton
3e4b3e1f68 cifs: add separate cred_uid field to sesInfo
Right now, there's no clear separation between the uid that owns the
credentials used to do the mount and the overriding owner of the files
on that mount.

Add a separate cred_uid field that is set to the real uid
of the mount user. Unlike the linux_uid, the uid= option does not
override this parameter. The parm is sent to cifs.upcall, which can then
preferentially use the creduid= parm instead of the uid= parm for
finding credentials.

This is not the only way to solve this. We could try to do all of this
in kernel instead by having a module parameter that affects what gets
passed in the uid= field of the upcall. That said, we have a lot more
flexibility to change things in userspace so I think it probably makes
sense to do it this way.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
2010-08-02 12:40:39 +00:00
Kulikov Vasiliy
f55fdcca6b fs: cifs: check kmalloc() result
If kmalloc() fails exit with -ENOMEM.

Signed-off-by: Kulikov Vasiliy <segooon@gmail.com>
Acked-by: Dave Kleikamp <shaggy@linux.vnet.ibm.com>
Acked-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
2010-08-02 12:40:39 +00:00
Steve French
0ccd48025f [CIFS] Missing ifdef
Signed-off-by: Steve French <sfrench@us.ibm.com>
2010-08-02 12:40:38 +00:00
Steve French
d0e6f44e6c [CIFS] Missing line from previous commit
CC: Suresh Jayaraman <sjayaraman@suse.de>
Signed-off-by: Steve French <sfrench@us.ibm.com>
2010-08-02 12:40:38 +00:00
Steve French
c5e04a3e49 [CIFS] Fix build break when CONFIG_CIFS_FSCACHE disabled
CC: Suresh Jayaraman <sjayaraman@suse.de>
Signed-off-by: Steve French <sfrench@us.ibm.com>
2010-08-02 12:40:38 +00:00
Suresh Jayaraman
fa1df75d4d cifs: add mount option to enable local caching
Add a mount option 'fsc' to enable local caching on CIFS.

I considered adding a separate debug bit for caching, but it appears that
debugging would be relatively easier with the normal CIFS_INFO level.

As the cifs-utils (userspace) changes are not done yet, this patch enables
'fsc' by default to enable testing.

Signed-off-by: Suresh Jayaraman <sjayaraman@suse.de>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
2010-08-02 12:40:37 +00:00
Suresh Jayaraman
56698236e1 cifs: read pages from FS-Cache
Read pages from a FS-Cache data storage object into a CIFS inode.

Signed-off-by: Suresh Jayaraman <sjayaraman@suse.de>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
2010-08-02 12:40:37 +00:00
Suresh Jayaraman
9dc06558c2 cifs: store pages into local cache
Store pages from an CIFS inode into the data storage object associated with
that inode.

Signed-off-by: Suresh Jayaraman <sjayaraman@suse.de>
Signed-off-by: Steve French <sfrench@us.ibm.com>
2010-08-02 12:40:37 +00:00
Suresh Jayaraman
85f2d6b44d cifs: FS-Cache page management
Takes care of invalidation and release of FS-Cache marked pages and also
invalidation of the FsCache page flag when the inode is removed.

Signed-off-by: Suresh Jayaraman <sjayaraman@suse.de>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
2010-08-02 12:40:36 +00:00
Suresh Jayaraman
9451a9a52f cifs: define inode-level cache object and register them
Define inode-level data storage objects (managed by cifsInodeInfo structs).
Each inode-level object is created in a super-block level object and is itself
a data storage object in to which pages from the inode are stored.

The inode object is keyed by UniqueId. The coherency data being used is
LastWriteTime, LastChangeTime and end of file reported by the server.

Signed-off-by: Suresh Jayaraman <sjayaraman@suse.de>
Signed-off-by: Steve French <sfrench@us.ibm.com>
2010-08-02 12:40:36 +00:00
Suresh Jayaraman
d03382ce9a cifs: define superblock-level cache index objects and register them
Define superblock-level cache index objects (managed by cifsTconInfo structs).
Each superblock object is created in a server-level index object and in itself
an index into which inode-level objects are inserted.

The superblock object is keyed by sharename. The UniqueId/IndexNumber is used to
validate that the exported share is the same since we accessed it last time.

Signed-off-by: Suresh Jayaraman <sjayaraman@suse.de>
Signed-off-by: Steve French <sfrench@us.ibm.com>
2010-08-02 12:40:36 +00:00
Jeff Layton
8913007e67 cifs: remove unused cifsUidInfo struct
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
2010-08-02 12:40:35 +00:00
Jeff Layton
4ff67b720c cifs: clean up cifs_find_smb_ses (try #2)
This patch replaces the earlier patch by the same name. The only
difference is that MAX_PASSWORD_SIZE has been increased to attempt to
match the limits that windows enforces.

Do a better job of matching sessions by authtype. Matching by username
for a Kerberos session is incorrect, and anonymous sessions need special
handling.

Also, in the case where we do match by username, we also need to match
by password. That ensures that someone else doesn't "borrow" an existing
session without needing to know the password.

Finally, passwords can be longer than 16 bytes. Bump MAX_PASSWORD_SIZE
to 512 to match the size that the userspace mount helper allows.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
2010-08-02 12:40:35 +00:00
Jeff Layton
daf5b0b6f3 cifs: match secType when searching for existing tcp session
The secType is a per-tcp session entity, but the current routine doesn't
verify that it is acceptible when attempting to match an existing TCP
session.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
2010-08-02 12:40:35 +00:00
Jeff Layton
4515148ef7 cifs: move address comparison into separate function
Move the address comparator out of cifs_find_tcp_session and into a
separate function for cleanliness. Also change the argument to
that function to a "struct sockaddr" pointer. Passing pointers to
sockaddr_storage is a little odd since that struct is generally for
declaring static storage.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
2010-08-02 12:40:34 +00:00
Jeff Layton
50d971602a cifs: set the port in sockaddr in a more clearly defined fashion
This patch should replace the patch I sent a couple of weeks ago to
set the port in cifs_convert_address.

Currently we set this in cifs_find_tcp_session, but that's more of a
side effect than anything. Add a new function called cifs_fill_sockaddr.
Have it call cifs_convert_address and then set the port.

This also allows us to skip passing in the port as a separate parm to
cifs_find_tcp_session.

Also, change cifs_convert_address take a struct sockaddr * rather than
void * to make it clearer how this function should be called.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
2010-08-02 12:40:34 +00:00
Suresh Jayaraman
488f1d2d6c cifs: define server-level cache index objects and register them
Define server-level cache index objects (as managed by TCP_ServerInfo structs)
and register then with FS-Cache. Each server object is created in the CIFS
top-level index object and is itself an index into which superblock-level
objects are inserted.

The server objects are now keyed by {IPaddress,family,port} tuple.

Signed-off-by: Suresh Jayaraman <sjayaraman@suse.de>
Signed-off-by: Steve French <sfrench@us.ibm.com>
2010-08-02 12:40:34 +00:00
Suresh Jayaraman
f579cf3cfd cifs: register CIFS for caching
Define CIFS for FS-Cache and register for caching. Upon registration the
top-level index object cookie will be stuck to the netfs definition by
FS-Cache.

Signed-off-by: Suresh Jayaraman <sjayaraman@suse.de>
Signed-off-by: Steve French <sfrench@us.ibm.com>
2010-08-02 12:40:33 +00:00
Joe Perches
c21dfb699f fs/cifs: Remove unnecessary casts of private_data
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
2010-08-02 12:40:33 +00:00
Suresh Jayaraman
3feb41cff8 cifs: add kernel config option for CIFS Client caching support
Add a kernel config option to enable local caching for CIFS.

Signed-off-by: Suresh Jayaraman <sjayaraman@suse.de>
Signed-off-by: Steve French <sfrench@us.ibm.com>
2010-08-02 12:40:33 +00:00
Suresh Jayaraman
c6332e237f cifs: remove unused ip_address field in struct TCP_Server_Info
The ip_address field is not used and seems redundant as there is union addr
already and I don't see any future use as well.

Signed-off-by: Suresh Jayaraman <sjayaraman@suse.de>
Signed-off-by: Steve French <sfrench@us.ibm.com>
2010-08-02 12:40:33 +00:00
Suresh Jayaraman
e4317ceca2 cifs: remove an potentially confusing, obsolete comment
The recent commit 6ca9f3bae8 modified the code so
that filp is full instantiated whenever the file is created and passed back.
The below comment is no longer true, remove it.

Cc: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Suresh Jayaraman <sjayaraman@suse.de>
Signed-off-by: Steve French <sfrench@us.ibm.com>
2010-08-02 12:40:32 +00:00
Suresh Jayaraman
abd2e44dca cifs: guard cifsglob.h against multiple inclusion
Add conditional compile macros to guard the header file against multiple
inclusion.

Signed-off-by: Suresh Jayaraman <sjayaraman@suse.de>
Acked-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
2010-08-02 12:40:32 +00:00
David Howells
51c20fcced CIFS: Remove __exit mark from cifs_exit_dns_resolver()
Remove the __exit mark from cifs_exit_dns_resolver() as it's called by the
module init routine in case of error, and so may have been discarded during
linkage.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-07-30 18:56:09 -07:00
David Howells
4c0c03ca54 CIFS: Fix a malicious redirect problem in the DNS lookup code
Fix the security problem in the CIFS filesystem DNS lookup code in which a
malicious redirect could be installed by a random user by simply adding a
result record into one of their keyrings with add_key() and then invoking a
CIFS CFS lookup [CVE-2010-2524].

This is done by creating an internal keyring specifically for the caching of
DNS lookups.  To enforce the use of this keyring, the module init routine
creates a set of override credentials with the keyring installed as the thread
keyring and instructs request_key() to only install lookup result keys in that
keyring.

The override is then applied around the call to request_key().

This has some additional benefits when a kernel service uses this module to
request a key:

 (1) The result keys are owned by root, not the user that caused the lookup.

 (2) The result keys don't pop up in the user's keyrings.

 (3) The result keys don't come out of the quota of the user that caused the
     lookup.

The keyring can be viewed as root by doing cat /proc/keys:

2a0ca6c3 I-----     1 perm 1f030000     0     0 keyring   .dns_resolver: 1/4

It can then be listed with 'keyctl list' by root.

	# keyctl list 0x2a0ca6c3
	1 key in keyring:
	726766307: --alswrv     0     0 dns_resolver: foo.bar.com

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-and-Tested-by: Jeff Layton <jlayton@redhat.com>
Acked-by: Steve French <smfrench@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-07-22 09:42:40 -07:00
Jeff Layton
8a224d4894 cifs: remove bogus first_time check in NTLMv2 session setup code
This bug appears to be the result of a cut-and-paste mistake from the
NTLMv1 code. The function to generate the MAC key was commented out, but
not the conditional above it. The conditional then ended up causing the
session setup key not to be copied to the buffer unless this was the
first session on the socket, and that made all but the first NTLMv2
session setup fail.

Fix this by removing the conditional and all of the commented clutter
that made it difficult to see.

Cc: Stable <stable@kernel.org>
Reported-by: Gunther Deschner <gdeschne@redhat.com>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
2010-06-16 13:40:18 -04:00
Jeff Layton
47c78b7f40 cifs: don't call cifs_new_fileinfo unless cifs_open succeeds
It's currently possible for cifs_open to fail after it has already
called cifs_new_fileinfo. In that situation, the new fileinfo will be
leaked as the caller doesn't call fput. That in turn leads to a busy
inodes after umount problem since the fileinfo holds an extra inode
reference now. Shuffle cifs_open around a bit so that it only calls
cifs_new_fileinfo if it's going to succeed.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Reviewed-and-Tested-by: Suresh Jayaraman <sjayaraman@suse.de>
2010-06-16 13:40:17 -04:00
Suresh Jayaraman
d9d5d8df95 cifs: don't ignore cifs_posix_open_inode_helper return value
...and ensure that we propagate the error back to avoid any surprises.

Signed-off-by: Suresh Jayaraman <sjayaraman@suse.de>
Reviewed-and-Tested-by: Jeff Layton <jlayton@redhat.com>
2010-06-16 13:40:17 -04:00
Jeff Layton
db460242bf cifs: clean up arguments to cifs_open_inode_helper
...which takes a ton of unneeded arguments and does a lot more pointer
dereferencing than is really needed.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Reviewed-and-Tested-by: Suresh Jayaraman <sjayaraman@suse.de>
2010-06-16 13:40:17 -04:00
Jeff Layton
6ca9f3bae8 cifs: pass instantiated filp back after open call
The current scheme of sticking open files on a list and assuming that
cifs_open will scoop them off of it is broken and leads to "Busy
inodes after umount..." errors at unmount time.

The problem is that there is no guarantee that cifs_open will always
be called after a ->lookup or ->create operation. If there are
permissions or other problems, then it's quite likely that it *won't*
be called.

Fix this by fully instantiating the filp whenever the file is created
and pass that filp back to the VFS. If there is a problem, the VFS
can clean up the references.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Reviewed-and-Tested-by: Suresh Jayaraman <sjayaraman@suse.de>
2010-06-16 13:40:16 -04:00
Jeff Layton
2422f676fb cifs: move cifs_new_fileinfo call out of cifs_posix_open
Having cifs_posix_open call cifs_new_fileinfo is problematic and
inconsistent with how "regular" opens work. It's also buggy as
cifs_reopen_file calls this function on a reconnect, which creates a new
struct cifsFileInfo that just gets leaked.

Push it out into the callers. This also allows us to get rid of the
"mnt" arg to cifs_posix_open.

Finally, in the event that a cifsFileInfo isn't or can't be created, we
always want to close the filehandle out on the server as the client
won't have a record of the filehandle and can't actually use it. Make
sure that CIFSSMBClose is called in those cases.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Reviewed-and-Tested-by: Suresh Jayaraman <sjayaraman@suse.de>
2010-06-16 13:40:16 -04:00
Jeff Layton
12420ac341 cifs: implement drop_inode superblock op
The standard behavior for drop_inode is to delete the inode when the
last reference to it is put and the nlink count goes to 0. This helps
keep inodes that are still considered "not deleted" in cache as long as
possible even when there aren't dentries attached to them.

When server inode numbers are disabled, it's not possible for cifs_iget
to ever match an existing inode (since inode numbers are generated via
iunique). In this situation, cifs can keep a lot of inodes in cache that
will never be used again.

Implement a drop_inode routine that deletes the inode if server inode
numbers are disabled on the mount. This helps keep the cifs inode
caches down to a more manageable size when server inode numbers are
disabled.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
2010-06-12 02:06:52 +00:00
Jeff Layton
ed0e3ace57 cifs: don't attempt busy-file rename unless it's in same directory
Busy-file renames don't actually work across directories, so we need
to limit this code to renames within the same dir.

This fixes the bug detailed here:

    https://bugzilla.redhat.com/show_bug.cgi?id=591938

Signed-off-by: Jeff Layton <jlayton@redhat.com>
CC: Stable <stable@kernel.org>
Signed-off-by: Steve French <sfrench@us.ibm.com>
2010-06-12 01:45:36 +00:00
Jeff Layton
06b43672a9 cifs: fix page refcount leak
Commit 315e995c63 is causing OOM kills
when stress-testing a CIFS filesystem. The VFS readpages operation takes
a page reference. The older code just handed this reference off to the
page cache, but the new code takes an extra one. The simplest fix is to
put the new reference after add_to_page_cache_lru.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Acked-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Steve French <sfrench@us.ibm.com>
2010-06-01 17:15:52 +00:00
Christoph Hellwig
7ea8085910 drop unused dentry argument to ->fsync
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2010-05-27 22:05:02 -04:00
Jeff Layton
4065c802da cifs: fix noserverino handling when unix extensions are enabled
The uniqueid field sent by the server when unix extensions are enabled
is currently used sometimes when it shouldn't be. The readdir codepath
is correct, but most others are not. Fix it.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
2010-05-17 20:59:21 +00:00
Jeff Layton
84f30c66c3 cifs: don't update uniqueid in cifs_fattr_to_inode
We use this value to find an inode within the hash bucket, so we can't
change this without re-hashing the inode. For now, treat this value
as immutable.

Eventually, we should probably use an inode number change on a path
based operation to indicate that the lookup cache is invalid, but that's
a bit more code to deal with.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
2010-05-17 20:57:27 +00:00
Jeff Layton
db19272edc cifs: always revalidate hardlinked inodes when using noserverino
The old cifs_revalidate logic always revalidated hardlinked inodes.
This hack allowed CIFS to pass some connectathon tests when server inode
numbers aren't used (basic test7, in particular).

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
2010-05-17 20:55:58 +00:00
Steve French
baa4563317 Merge branch 'master' of /pub/scm/linux/kernel/git/torvalds/linux-2.6
Conflicts:
	fs/cifs/inode.c
2010-05-13 22:19:32 +00:00