cifs_filldir() copies the entry name out of an SMB1 TRANS2_FIND_FIRST /
FIND_NEXT response using a length (de.namelen) supplied by the server.
The kmalloc'd SMB response buffer is bounded, but nothing checks that
de.name + de.namelen still lies inside that buffer before the eventual
filldir64() -> verify_dirent_name() -> memchr() reads namelen bytes.
A hostile SMB1 server that returns an oversized FileNameLength in a
directory entry therefore causes memchr() to read past the end of the
response slab buffer. Reachable from any user who can list a directory
on a CIFS mount served by an attacker-controlled server (getdents64()
on the mounted directory):
BUG: KASAN: slab-out-of-bounds in memchr+0x71/0x80
Read of size 1 at addr ffff88800e0640cc by task poc/115
Call Trace:
dump_stack_lvl+0x64/0x80
print_report+0xce/0x620
kasan_report+0xec/0x120
memchr+0x71/0x80
filldir64+0x4c/0x6a0
cifs_filldir.constprop.0+0x9bb/0x1e00
cifs_readdir+0x2101/0x3380
iterate_dir+0x19c/0x520
__x64_sys_getdents64+0x126/0x210
do_syscall_64+0x107/0x5a0
entry_SYSCALL_64_after_hwframe+0x77/0x7f
Pass the end-of-response pointer down to cifs_filldir() and reject
entries whose name would extend past that boundary.
This bug was discovered by Artiphishell's vTriage pipeline, which
generated a userspace reproducer (an emulated hostile SMB1 server plus
a getdents64() client) that reliably triggers the KASAN report on an
unpatched kernel. The fix below was drafted with the Claude coding
assistant; a userspace reproducer is available on request.
Assisted-by: Claude:claude-opus-4-7
Signed-off-by: Jay Vadayath <jay@artiphishell.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Extend cifs_autodisable_serverino() function to print also text message why
the function was called.
The text message is printed just once for mount then autodisabling
serverino support. Once the serverino support is disabled for mount it will
not be re-enabled. So those text messages do not cause flooding logs.
This change allows to debug issues why cifs.ko decide to turn off server
inode number support and hence disable support for detection of hardlinks.
Signed-off-by: Pali Rohár <pali@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
QueryDirectory responses today are stored in one of two fixed
sized buffers: smallbuf (448 bytes) or bigbuf (16KB). These are
borrowed from server struct and are not sufficient for large-sized
query dir operations.
With this change we will now define a new buffer type specifically
for cifs_search_info to hold variable sized responses. These will
be allocated by kmalloc and freed by kfree.
Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Parallel lookup starts with a call of d_alloc_parallel(). That primitive
either returns a matching hashed dentry or allocates a new one in the
in-lookup state and returns it to the caller. Once the caller is done
with lookup, it indicates so either by call of d_{splice_alias,add}()
or by call of d_done_lookup(); at that point dentry leaves the in-lookup
state.
If d_alloc_parallel() finds a matching in-lookup dentry, it must wait for
that dentry to leave the in-lookup state, one way or another. Currently
by supplying wait_queue_head to d_alloc_parallel(). If d_alloc_parallel()
creates a new in-lookup dentry, the address of that wait_queue_head is stored
in ->d_wait of new dentry and stays there while it's in the in-lookup;
subsequent d_alloc_parallel() will wait on the queue found in the matching
in-lookup dentry. Transition out of in-lookup state wakes waiters on that
queue (if any).
That works, but the calling conventions are inconvenient - the caller must
supply wait_queue_head and make sure that it survives at least until the new
in-lookup dentry leaves the in-lookup state. That amounts to boilerplate
in the d_alloc_parallel() callers that are followed by a call of d_lookup_done()
in the same function; in cases like nfs asynchronous unlink it gets worse than
that.
This patch changes d_alloc_parallel() to use wake_up_var_locked() to
wake up waiters, and wait_var_event_spinlock() to wait. dentry->d_lock
is used for synchronisation as it is already held and the relevant
times.
That eliminates the need of caller-supplied wait_queue_head, simplifying
the calling conventions. Better yet, we only need one bit of information
stored in dentry itself: whether there are any waiters to be woken up,
and that can be easily stored in ->d_flags; ->d_wait goes away.
The reason we need that bit (DCACHE_LOOKUP_WAITERS) is that with wait_var
machinery the queues are shared with all kinds of stuff and there's
no way tell if any of the waiters have anything to do with our dentry;
most of the time none of them will be relevant, so we need to avoid the
pointless wakeups.
Another benefit of the new scheme comes from the fact that wakeups
have to be done outside of write-side critical areas of ->i_dir_seq;
with the old scheme we need to carry the value picked from ->d_wait from
__d_lookup_unhash() to the place where we actually wake the waiters up.
Now we can just leave DCACHE_LOOKUP_WAITERS in ->d_flags until we get
to doing wakeups - that's done within the same ->d_lock scope, so we
are fine; new bit is accessed only under ->d_lock and it's seen only
on dentries with DCACHE_PAR_LOOKUP in ->d_flags.
__d_lookup_unhash() no longer needs to re-init ->d_lru. That was
previously shared (in a union) with ->d_wait but ->d_wait is now gone
so it no longer corrupts ->d_lru.
Co-developed-by: Al Viro <viro@zeniv.linux.org.uk> # saner handling of flags
Signed-off-by: NeilBrown <neil@brown.name>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Fix potential tearing in using ->remote_i_size and ->zero_point by copying
i_size_read() and i_size_write() and using the same seqcount as for i_size.
We need to make sure that netfslib and the filesystems that use it always
hold i_lock whilst updating any of the sizes to prevent i_size_seqcount
from getting corrupted.
Fixes: 4058f74210 ("netfs: Keep track of the actual remote file size")
Fixes: 100ccd18bb ("netfs: Optimise away reads above the point at which there can be no data")
Closes: https://sashiko.dev/#/patchset/20260414082004.3756080-1-dhowells%40redhat.com
Signed-off-by: David Howells <dhowells@redhat.com>
Link: https://patch.msgid.link/20260512123404.719402-6-dhowells@redhat.com
cc: Paulo Alcantara <pc@manguebit.org>
cc: Matthew Wilcox <willy@infradead.org>
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
Use atomic_t for cifs_sb_info::mnt_cifs_flags as it's currently
accessed locklessly and may be changed concurrently in mount/remount
and reconnect paths.
Signed-off-by: Paulo Alcantara (Red Hat) <pc@manguebit.org>
Reviewed-by: David Howells <dhowells@redhat.com>
Cc: linux-cifs@vger.kernel.org
Signed-off-by: Steve French <stfrench@microsoft.com>
This was done entirely with mindless brute force, using
git grep -l '\<k[vmz]*alloc_objs*(.*, GFP_KERNEL)' |
xargs sed -i 's/\(alloc_objs*(.*\), GFP_KERNEL)/\1)/'
to convert the new alloc_obj() users that had a simple GFP_KERNEL
argument to just drop that argument.
Note that due to the extreme simplicity of the scripting, any slightly
more complex cases spread over multiple lines would not be triggered:
they definitely exist, but this covers the vast bulk of the cases, and
the resulting diff is also then easier to check automatically.
For the same reason the 'flex' versions will be done as a separate
conversion.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This is the result of running the Coccinelle script from
scripts/coccinelle/api/kmalloc_objs.cocci. The script is designed to
avoid scalar types (which need careful case-by-case checking), and
instead replace kmalloc-family calls that allocate struct or union
object instances:
Single allocations: kmalloc(sizeof(TYPE), ...)
are replaced with: kmalloc_obj(TYPE, ...)
Array allocations: kmalloc_array(COUNT, sizeof(TYPE), ...)
are replaced with: kmalloc_objs(TYPE, COUNT, ...)
Flex array allocations: kmalloc(struct_size(PTR, FAM, COUNT), ...)
are replaced with: kmalloc_flex(*PTR, FAM, COUNT, ...)
(where TYPE may also be *VAR)
The resulting allocations no longer return "void *", instead returning
"TYPE *".
Signed-off-by: Kees Cook <kees@kernel.org>
Split SMB1 protocol defs into smb1pdu.h. This should perhaps go in the
common/ directory.
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Steve French <sfrench@samba.org>
cc: Paulo Alcantara <pc@manguebit.org>
cc: Enzo Matsumiya <ematsumiya@suse.de>
cc: linux-cifs@vger.kernel.org
cc: linux-fsdevel@vger.kernel.org
cc: linux-kernel@vger.kernel.org
Acked-by: Enzo Matsumiya <ematsumiya@suse.de>
Signed-off-by: Steve French <stfrench@microsoft.com>
Add a tracepoint to log EIO errors and give it the capacity to convey up to
two integers of information. This is then wrapped with three functions:
int smb_EIO(enum smb_eio_trace trace)
int smb_EIO1(enum smb_eio_trace trace, unsigned long info)
int smb_EIO2(enum smb_eio_trace trace, unsigned long info,
unsigned long info2)
depending on how many bits of info are desired to be logged with any
particular trace. The functions all return -EIO and can be used in place
of -EIO.
The trace argument is an enum value that gets translated to a string when
the trace is printed.
This makes is easier to log EIO instances when the client is under high
load than turning on a printk wrapper such as cifs_dbg(). Granted, EIO
could have its own separate EIO printing since EIO shouldn't happen.
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Paulo Alcantara (Red Hat) <pc@manguebit.org>
cc: linux-cifs@vger.kernel.org
cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Steve French <stfrench@microsoft.com>
Modify the following places:
- Add documentation references
- ATTR_REPARSE -> ATTR_REPARSE_POINT: consistent with MS-SMB 2.2.1.2.1
- Remove unused File Attribute flags from server, if the server uses
them in the future, we can move the client-side definitions to common
- Remove unused SMB1_CLIENT_GUID_SIZE from server
Signed-off-by: ChenXiaoSong <chenxiaosong@kylinos.cn>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
Modify the following places:
- smb2_file_ntwrk_info -> smb2_file_network_open_info
- struct filesystem_device_info -> FILE_SYSTEM_DEVICE_INFO
- struct file_directory_info -> FILE_DIRECTORY_INFO
- struct file_full_directory_info -> FILE_FULL_DIRECTORY_INFO
- struct file_both_directory_info -> FILE_BOTH_DIRECTORY_INFO
- struct file_id_full_dir_info -> FILE_ID_FULL_DIR_INFO
- struct filesystem_posix_info -> FILE_SYSTEM_POSIX_INFO
The fields of these structures are exactly the same on both client and
server, so move duplicate definitions to common header file.
Signed-off-by: ChenXiaoSong <chenxiaosong@kylinos.cn>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
Add lightweight accounting for directory lease cache usage
to aid debugging and limiting cache size in future. Track
per-directory entry/byte counts and maintain per-tcon
aggregates. Also expose the totals in /proc/fs/cifs/open_dirs.
Signed-off-by: Bharath SM <bharathsm@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
When SMB 3.1.1 POSIX Extensions are negotiated, userspace applications
using readdir() or getdents() calls without stat() on each individual file
(such as a simple "ls" or "find") would misidentify file types and exhibit
strange behavior such as not descending into directories. The reason for
this behavior is an oversight in the cifs_posix_to_fattr conversion
function. Instead of extracting the entry type for cf_dtype from the
properly converted cf_mode field, it tries to extract the type from the
PDU. While the wire representation of the entry mode is similar in
structure to POSIX stat(), the assignments of the entry types are
different. Applying the S_DT macro to cf_mode instead yields the correct
result. This is also what the equivalent function
smb311_posix_info_to_fattr in inode.c already does for stat() etc.; which
is why "ls -l" would give the correct file type but "ls" would not (as
identified by the colors).
Cc: stable@vger.kernel.org
Signed-off-by: Philipp Kerling <pkerling@casix.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
Currently, cached directory contents were not reused across subsequent
'ls' operations because the cache validity check relied on comparing
the ctx pointer, which changes with each readdir invocation. As a
result, the cached dir entries was not marked as valid and the cache was
not utilized for subsequent 'ls' operations.
This change uses the file pointer, which remains consistent across all
readdir calls for a given directory instance, to associate and validate
the cache. As a result, cached directory contents can now be
correctly reused, improving performance for repeated directory listings.
Performance gains with local windows SMB server:
Without the patch and default actimeo=1:
1000 directory enumeration operations on dir with 10k files took 135.0s
With this patch and actimeo=0:
1000 directory enumeration operations on dir with 10k files took just 5.1s
Signed-off-by: Bharath SM <bharathsm@microsoft.com>
Reviewed-by: Shyam Prasad N <sprasad@microsoft.com>
Cc: stable@vger.kernel.org
Signed-off-by: Steve French <stfrench@microsoft.com>
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Merge tag 'vfs-6.16-rc1.async.dir' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs
Pull vfs directory lookup updates from Christian Brauner:
"This contains cleanups for the lookup_one*() family of helpers.
We expose a set of functions with names containing "lookup_one_len"
and others without the "_len". This difference has nothing to do with
"len". It's rater a historical accident that can be confusing.
The functions without "_len" take a "mnt_idmap" pointer. This is found
in the "vfsmount" and that is an important question when choosing
which to use: do you have a vfsmount, or are you "inside" the
filesystem. A related question is "is permission checking relevant
here?".
nfsd and cachefiles *do* have a vfsmount but *don't* use the non-_len
functions. They pass nop_mnt_idmap and refuse to work on filesystems
which have any other idmap.
This work changes nfsd and cachefile to use the lookup_one family of
functions and to explictily pass &nop_mnt_idmap which is consistent
with all other vfs interfaces used where &nop_mnt_idmap is explicitly
passed.
The remaining uses of the "_one" functions do not require permission
checks so these are renamed to be "_noperm" and the permission
checking is removed.
This series also changes these lookup function to take a qstr instead
of separate name and len. In many cases this simplifies the call"
* tag 'vfs-6.16-rc1.async.dir' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
VFS: change lookup_one_common and lookup_noperm_common to take a qstr
Use try_lookup_noperm() instead of d_hash_and_lookup() outside of VFS
VFS: rename lookup_one_len family to lookup_noperm and remove permission check
cachefiles: Use lookup_one() rather than lookup_one_len()
nfsd: Use lookup_one() rather than lookup_one_len()
VFS: improve interface for lookup_one functions
Multiple pointers in struct cifs_search_info (ntwrk_buf_start,
srch_entries_start, and last_entry) point to the same allocated buffer.
However, when freeing this buffer, only ntwrk_buf_start was set to NULL,
while the other pointers remained pointing to freed memory.
This is defensive programming to prevent potential issues with stale
pointers. While the active UAF vulnerability is fixed by the previous
patch, this change ensures consistent pointer state and more robust error
handling.
Signed-off-by: Wang Zhaolong <wangzhaolong1@huawei.com>
Cc: stable@vger.kernel.org
Reviewed-by: Paulo Alcantara (Red Hat) <pc@manguebit.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
try_lookup_noperm() and d_hash_and_lookup() are nearly identical. The
former does some validation of the name where the latter doesn't.
Outside of the VFS that validation is likely valuable, and having only
one exported function for this task is certainly a good idea.
So make d_hash_and_lookup() local to VFS files and change all other
callers to try_lookup_noperm(). Note that the arguments are swapped.
Signed-off-by: NeilBrown <neilb@suse.de>
Link: https://lore.kernel.org/r/20250319031545.2999807-6-neil@brown.name
Signed-off-by: Christian Brauner <brauner@kernel.org>
In all other places is used function cifs_autodisable_serverino() for
disabling CIFS_MOUNT_SERVER_INUM mount flag. So use is also in readir.c
_initiate_cifs_search() function. Benefit of cifs_autodisable_serverino()
is that it also prints dmesg message that server inode numbers are being
disabled.
Fixes: ec06aedd44 ("cifs: clean up handling when server doesn't consistently support inode numbers")
Fixes: f534dc9943 ("cifs: clear server inode number flag while autodisabling")
Signed-off-by: Pali Rohár <pali@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
Some servers which implement the SMB3.1.1 POSIX extensions did not
set the file type in the mode in the infolevel 100 response.
With the recent changes for checking the file type via the mode field,
this can cause the root directory to be reported incorrectly and
mounts (e.g. to ksmbd) to fail.
Fixes: 6a832bc8bb ("fs/smb/client: Implement new SMB3 POSIX type")
Cc: stable@vger.kernel.org
Acked-by: Paulo Alcantara (Red Hat) <pc@manguebit.com>
Cc: Ralph Boehme <slow@samba.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
Spares an extra revalidation request
Cc: stable@vger.kernel.org
Acked-by: Paulo Alcantara (Red Hat) <pc@manguebit.com>
Signed-off-by: Ralph Boehme <slow@samba.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
Parse the extended attributes from WSL reparse points to correctly
report uid, gid mode and dev from ther instantiated inodes.
Signed-off-by: Paulo Alcantara <pc@manguebit.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
In preparation to add support for creating special files also via WSL
reparse points in next commits.
Signed-off-by: Paulo Alcantara <pc@manguebit.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
In cases of large directories, the readdir operation may span multiple
round trips to retrieve contents. This introduces a potential race
condition in case of concurrent write and readdir operations. If the
readdir operation initiates before a write has been processed by the
server, it may update the file size attribute to an older value.
Address this issue by avoiding file size updates from readdir when we
have read/write lease.
Scenario:
1) process1: open dir xyz
2) process1: readdir instance 1 on xyz
3) process2: create file.txt for write
4) process2: write x bytes to file.txt
5) process2: close file.txt
6) process2: open file.txt for read
7) process1: readdir 2 - overwrites file.txt inode size to 0
8) process2: read contents of file.txt - bug, short read with 0 bytes
Cc: stable@vger.kernel.org
Reviewed-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Bharath SM <bharathsm@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Send query dir requests with an info level of
SMB_FIND_FILE_FULL_DIRECTORY_INFO rather than
SMB_FIND_FILE_DIRECTORY_INFO when the client is generating its own
inode numbers (e.g. noserverino) so that reparse tags still
can be parsed directly from the responses, but server won't
send UniqueId (server inode number)
Signed-off-by: Paulo Alcantara <pc@manguebit.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Use cifsi->netfs_ctx.remote_i_size instead of cifsi->server_eof so that
netfslib can refer to it to.
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Shyam Prasad N <nspmangalore@gmail.com>
cc: Rohith Surabattula <rohiths.msft@gmail.com>
cc: Jeff Layton <jlayton@kernel.org>
cc: linux-cifs@vger.kernel.org
cc: linux-cachefs@redhat.com
cc: linux-fsdevel@vger.kernel.org
cc: linux-mm@kvack.org
Signed-off-by: Steve French <stfrench@microsoft.com>
Don't clobber ->i_rdev from valid reparse inodes over readdir(2) as it
can't be provided by query dir responses.
Signed-off-by: Paulo Alcantara <pc@manguebit.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
minor comment cleanup and trivial camelCase removal
Reviewed-by: Bharath SM <bharathsm@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Query dir responses don't provide enough information on reparse points
such as major/minor numbers and symlink targets other than reparse
tags, however we don't need to unconditionally revalidate them only
because they are reparse points. Instead, revalidate them only when
their ctime or reparse tag has changed.
For instance, Windows Server updates ctime of reparse points when
their data have changed.
Signed-off-by: Paulo Alcantara (SUSE) <pc@manguebit.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Handle all file types in NFS reparse points as specified in MS-FSCC
2.1.2.6 Network File System (NFS) Reparse Data Buffer.
The client is now able to set all file types based on the parsed NFS
reparse point, which used to support only symlinks. This works for
SMB1+.
Before patch:
$ mount.cifs //srv/share /mnt -o ...
$ ls -l /mnt
ls: cannot access 'block': Operation not supported
ls: cannot access 'char': Operation not supported
ls: cannot access 'fifo': Operation not supported
ls: cannot access 'sock': Operation not supported
total 1
l????????? ? ? ? ? ? block
l????????? ? ? ? ? ? char
-rwxr-xr-x 1 root root 5 Nov 18 23:22 f0
l????????? ? ? ? ? ? fifo
l--------- 1 root root 0 Nov 18 23:23 link -> f0
l????????? ? ? ? ? ? sock
After patch:
$ mount.cifs //srv/share /mnt -o ...
$ ls -l /mnt
total 1
brwxr-xr-x 1 root root 123, 123 Nov 18 00:34 block
crwxr-xr-x 1 root root 1234, 1234 Nov 18 00:33 char
-rwxr-xr-x 1 root root 5 Nov 18 23:22 f0
prwxr-xr-x 1 root root 0 Nov 18 23:23 fifo
lrwxr-xr-x 1 root root 0 Nov 18 23:23 link -> f0
srwxr-xr-x 1 root root 0 Nov 19 2023 sock
Signed-off-by: Paulo Alcantara (SUSE) <pc@manguebit.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Check for reparse point flag on query info calls as specified in
MS-SMB2 2.2.14.
Signed-off-by: Paulo Alcantara (SUSE) <pc@manguebit.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>
