Pull smb client fixes from Steve French:
- fix uninitialized variable in smb2_writev_callback()
- detect short folioq copy in cifs_copy_folioq_to_iter()
* tag 'v7.1-rc6-smb3-client-fixes' of git://git.samba.org/sfrench/cifs-2.6:
smb: client: fix uninitialized variable in smb2_writev_callback
smb: client: detect short folioq copy in cifs_copy_folioq_to_iter()
cifs_copy_folioq_to_iter() copies a requested number of bytes from
a folio queue into the destination iterator. Since the encrypted
SMB2 READ path was changed to pass the server-declared payload
length (data_len) instead of the larger folioq buffer length, the
caller can ask for fewer bytes than the folio queue holds.
In that case the helper continues walking the remaining folios after
data_size has reached zero and calls copy_folio_to_iter() with
len = 0, which is unnecessary work.
The helper also returns 0 (success) when the folio queue is
exhausted before data_size bytes have been copied. The caller has
no way to distinguish that from a full copy and the reported
transfer count ends up larger than the amount of data placed in the
iterator.
Add an early exit when data_size reaches zero, and return an error
when the folio queue is exhausted before all requested bytes have
been copied.
Signed-off-by: Jeremy Erazo <mendozayt13@gmail.com>
Reviewed-by: David Howells <dhowells@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
FSCTL_SET_SPARSE in fsctl_set_sparse() modifies the file's sparse
attribute and saves it through xattr without any permission checks.
This exposes two issues:
1) A client on a read-only share can change the sparse attribute
on files it opened, even though the share is read-only.
Other FSCTL write operations already check
test_tree_conn_flag(work->tcon, KSMBD_TREE_CONN_FLAG_WRITABLE),
but FSCTL_SET_SPARSE does not.
2) Even on writable shares, clients without FILE_WRITE_DATA or
FILE_WRITE_ATTRIBUTES access should not modify the sparse
attribute. Similar handle-level checks exist in other functions
but are missing here.
Add both share-level writable check and per-handle access check.
Use goto out on error to avoid leaking file references.
Fixes: e2f34481b2 ("cifsd: add server-side procedures for SMB3")
Cc: Namjae Jeon <linkinjeon@kernel.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Steve French <smfrench@gmail.com>
Signed-off-by: Sean Shen <grayhat@foxmail.com>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
ksmbd_query_inode_status() and ksmbd_lookup_fd_inode() both take a
reference on a ksmbd_inode via __ksmbd_inode_lookup() (which performs
atomic_inc_not_zero()) and later release it using a bare
atomic_dec(&ci->m_count). Unlike ksmbd_inode_put(), a bare
atomic_dec() does not check whether the reference count has reached
zero, so if the caller happens to drop the last reference, the
ksmbd_inode is leaked: it stays in the global inode hash table with
m_count == 0, future __ksmbd_inode_lookup() calls reject it via
atomic_inc_not_zero(), and ksmbd_inode_free() is never invoked.
The race is:
T1: __ksmbd_inode_lookup() -> atomic_inc_not_zero(): m_count = 2
T2: ksmbd_inode_put() -> atomic_dec_and_test(): m_count = 1
(not freed)
T1: atomic_dec(&ci->m_count) -> m_count = 0
return (LEAK)
In ksmbd_lookup_fd_inode() the matched-fp path (which now also uses
ksmbd_inode_put()) cannot currently reach m_count == 0 because the
matched ksmbd_file holds its own reference on ci, but converting it to
the proper API keeps the three call sites consistent and avoids
future regressions if the locking changes.
Because ksmbd_inode_put() may free the ksmbd_inode if this drops the
last reference, the call must happen after up_read(&ci->m_lock) on the
two affected paths in ksmbd_lookup_fd_inode(). On the no-match path
this is a pure reordering; on the matched path ksmbd_fp_get() is
moved above the unlock so that the returned ksmbd_file is pinned
before the inode reference is released.
Signed-off-by: Aleksandr Golovnya <cofedish@gmail.com>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
Commit d07b26f392 ("ksmbd: require minimum ACE size in
smb_check_perm_dacl()") introduced a transposed bounds check:
if (offsetof(struct smb_ace, sid) + aces_size < CIFS_SID_BASE_SIZE)
Since offsetof(..sid) is 8 and CIFS_SID_BASE_SIZE is 8, this evaluates
to `aces_size < 0`. Because `aces_size` is always non-negative, this
check becomes dead code and never breaks the loop.
Worse, that commit removed the old 4-byte guard, meaning the loop now
reads `ace->size` (offset 2) even when `aces_size` is 0-3 bytes. This
re-opens a 2-byte heap out-of-bounds (OOB) read past the pntsd allocation
during subsequent SMB2_CREATE operations.
Fix this by properly transposing the comparison to require at least
16 bytes (8-byte offset + 8-byte SID base), matching the correct form
used in smb_inherit_dacl().
Fixes: d07b26f392 ("ksmbd: require minimum ACE size in smb_check_perm_dacl()")
Cc: stable@vger.kernel.org
Signed-off-by: Ali Ganiyev <ali.qaniyev@gmail.com>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
Pull smb server fixes from Steve French:
- fix for creating tmpfiles
- fix durable reconnect error path
- validate SID in security descriptor when inheriting DACL
* tag 'v7.1-rc5-ksmbd-server-fixes' of git://git.samba.org/ksmbd:
smb/server: promote S_DEL_ON_CLS to S_DEL_PENDING when close
ksmbd: validate SID in parent security descriptor during ACL inheritance
ksmbd: fix durable reconnect error path file lifetime
Pull smb client fixes from Steve French:
- Fix missing lock
- Fix dentry in use after unmounting
- cifs.upcall security fix
- require CAP_NET_ADMIN for swn netlink
- change allocation in DUP_CTX_STR to GFP_KERNEL
- minor smbdirect debug fix
- handle_read_data() folio fix
* tag 'v7.1-rc5-smb3-client-fixes' of git://git.samba.org/sfrench/cifs-2.6:
smb: client: change allocation requirements in DUP_CTX_STR macro
smb: client: require net admin for CIFS SWN netlink
smb: smbdirect: divide, not multiply, milliseconds by 1000
cifs: Fix busy dentry used after unmounting
smb: client: use data_len for SMB2 READ encrypted folioq copy
smb: client: reject userspace cifs.spnego descriptions
smb: client: protect tc_count increment in smb2_find_smb_sess_tcon_unlocked()
Introduce smb_validate_ntsd_sid() helper to safely validate Owner SID
and Group SID inside the NT Security Descriptor (smb_ntsd) retrieved
from the parent directory.
Cc: stable@vger.kernel.org
Signed-off-by: Junyi Liu <moss80199@gmail.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
After a durable reconnect succeeds, ksmbd_reopen_durable_fd() republishes
the same ksmbd_file into the session volatile-id table. If smb2_open()
then takes a later error path, cleanup first calls ksmbd_fd_put(work, fp)
and then unconditionally calls ksmbd_put_durable_fd(dh_info.fp).
In this case fp and dh_info.fp are the same object. The first put drops the
reconnect lookup reference, but the final durable put can run
__ksmbd_close_fd(NULL, fp). Because the final close is not session-aware,
it can free the file object without removing the volatile-id entry that was
just published into the session table.
Use the session-aware put for the final reconnect drop when the reconnect
had already succeeded and the error path is cleaning up the republished
file. Earlier reconnect failures, before fp is assigned to dh_info.fp, keep
using the durable-only put path.
Fixes: 1baff47b81 ("ksmbd: fix use-after-free in smb2_open during durable reconnect")
Signed-off-by: Junyi Liu <moss80199@gmail.com>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
Currently, the macro DUP_CTX_STR allocates new_ctx->field using
GFP_ATOMIC. DUP_CTX_STR is only used in smb3_fs_context_dup(), which
is never called in an atomic context. Using GFP_ATOMIC puts unnecessary
pressure on emergency memory pools.
Change GFP_ATOMIC to GFP_KERNEL.
Signed-off-by: Fredric Cover <fredric.cover.lkernel@gmail.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
CIFS_GENL_CMD_SWN_NOTIFY is the userspace witness-notify command. The
intended sender is the cifs.witness helper, but the generic-netlink
operation currently has no capability flag, so any local process can send
RESOURCE_CHANGE or CLIENT_MOVE notifications to the in-kernel witness
handler.
The same family exposes CIFS_GENL_MCGRP_SWN without multicast-group
capability flags. Register messages sent to that group include the witness
registration id and, for NTLM-authenticated mounts, the username, domain,
and password attributes copied from the CIFS session. An unprivileged
local process should not be able to join that group and receive those
messages.
Require CAP_NET_ADMIN for incoming SWN_NOTIFY commands with
GENL_ADMIN_PERM, and require CAP_NET_ADMIN over the network namespace for
joining the SWN multicast group with GENL_MCAST_CAP_NET_ADMIN. The
cifs.witness service runs with the privileges needed for both operations.
Fixes: fed979a7e0 ("cifs: Set witness notification handler for messages from userspace daemon")
Cc: stable@vger.kernel.org
Signed-off-by: Michael Bommarito <michael.bommarito@gmail.com>
Assisted-by: Claude:claude-opus-4-7
Signed-off-by: Steve French <stfrench@microsoft.com>
Unless smbdirect_connection_legacy_debug_proc_show()
wants to debug-log keep_alive_interval as microseconds,
a magnitude higher precision than available by the way,
keepalive_interval_msec should not be multiplied by 1000.
Fixes: cc55f65dd3 ("smb: client: make use of common smbdirect_socket_parameters")
Reviewed-by: Stefan Metzmacher <metze@samba.org>
Signed-off-by: Alexander A. Klimov <grandmaster@al2klimov.de>
Signed-off-by: Steve French <stfrench@microsoft.com>
Since commit 340cea84f6 ("cifs: open files should not hold ref on
superblock"), cifs file only holds the dentry ref_cnt, the cifs file
close work(cfile->deferred) could be executed after unmounting, which
will trigger a warning in generic_shutdown_super:
BUG: Dentry 00000000a14a6845{i=c,n=file} still in use (1) [unmount of
cifs cifs]
The detailed processs is:
process A process B kworker
fd = open(PATH)
vfs_open
file->__f_path = *path // dentry->d_lockref.count = 1
cifs_open
cifs_new_fileinfo
cfile->dentry = dget(dentry) // dentry->d_lockref.count = 2
close(fd)
__fput
cifs_close
queue_delayed_work(deferredclose_wq, cfile->deferred)
dput(dentry) // dentry->d_lockref.count = 1
smb2_deferred_work_close
_cifsFileInfo_put
list_del(&cifs_file->flist)
umount
cleanup_mnt
deactivate_super
cifs_kill_sb
cifs_close_all_deferred_files_sb
cifs_close_all_deferred_files
// cannot find cfile, skip _cifsFileInfo_put
kill_anon_super
generic_shutdown_super
shrink_dcache_for_umount
umount_check
WARN ! // dentry->d_lockref.count = 1
cifsFileInfo_put_final
dput(cifs_file->dentry)
// dentry->d_lockref.count = 0
Fix it by flushing 'deferredclose_wq' before calling kill_anon_super.
Fetch a reproducer in https://bugzilla.kernel.org/show_bug.cgi?id=221548.
Fixes: 340cea84f6 ("cifs: open files should not hold ref on superblock")
Cc: stable@vger.kernel.org
Reviewed-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Zhihao Cheng <chengzhihao1@huawei.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Pull smb server fixes from Steve French:
- Fix two null pointer dereferences and a memory leak
* tag 'v7.1-rc4-ksmbd-server-fixes' of git://git.samba.org/ksmbd:
ksmbd: fix null pointer dereference in compare_guid_key()
ksmbd: fix null pointer dereference in proc_show_files()
ksmbd: fix SID memory leak in set_posix_acl_entries_dacl() on overflow
In handle_read_data() the encrypted/folioq branch
(buf_len <= data_offset, reached via receive_encrypted_read for
transform PDUs > CIFSMaxBufSize + MAX_HEADER_SIZE) copies the READ
payload using buffer_len rather than data_len:
rdata->result = cifs_copy_folioq_to_iter(buffer, buffer_len,
cur_off,
&rdata->subreq.io_iter);
...
rdata->got_bytes = buffer_len;
buffer_len comes from the SMB3 transform header OriginalMessageSize
field (OriginalMessageSize - read_rsp_size); it represents the size
of the decrypted message after the SMB2 header. data_len comes from
the SMB2 READ response DataLength field; it represents the actual
READ payload size and may be smaller than buffer_len when the
decrypted message contains padding or other trailing bytes after the
READ payload. The existing check `data_len > buffer_len - pad_len`
only enforces an upper bound, so a server that emits
OriginalMessageSize larger than read_rsp_size + pad_len + data_len
passes the check and the kernel copies buffer_len bytes per response,
ignoring the server-asserted DataLength.
Two observable failures with a crafted server (DataLength=4,
buffer_len=20000):
- the kernel returns 20000 bytes per sub-request to userspace and
sets got_bytes = buffer_len, even though the response claimed
only 4 bytes of payload;
- on a partial netfs sub-request whose iterator is sized to
data_len, the over-large copy_folio_to_iter() short-reads,
cifs_copy_folioq_to_iter() returns -EIO via the n != len path,
and the entire netfs read collapses to -EIO even though the
leading sub-requests succeeded.
Use data_len for the copy length and for got_bytes so the kernel
honours the server-asserted READ payload size. For well-formed
servers (where buffer_len == pad_len + data_len) the change is
behaviour-equivalent.
Cc: stable@vger.kernel.org
Signed-off-by: Jeremy Erazo <mendozayt13@gmail.com>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
cifs.spnego key descriptions contain authority-bearing fields such as
pid, uid, creduid, and upcall_target that cifs.upcall treats as
kernel-originating inputs. However, userspace can also create keys of
this type through request_key(2) or add_key(2), allowing those fields to
be supplied without CIFS origin.
Only accept cifs.spnego descriptions while CIFS is using its private
spnego_cred to request the key.
Fixes: f1d662a7d5 ("[CIFS] Add upcall files for cifs to use spnego/kerberos")
Assisted-by: avom-custom-harness:gpt-5.5-qwen3.6-mod-mix
Reviewed-by: David Howells <dhowells@redhat.com>
Signed-off-by: Asim Viladi Oglu Manizada <manizada@pm.me>
Signed-off-by: Steve French <stfrench@microsoft.com>
Commit 96c4af4185 ("cifs: Fix locking usage for tcon fields")
refactored cifs code to change cifs_tcp_ses_lock for tc_lock around
tc_count changes.
There was missing lock around tc_count increment inside
smb2_find_smb_sess_tcon_unlocked().
Cc: stable@vger.kernel.org
Fixes: 96c4af4185 ("cifs: Fix locking usage for tcon fields")
Reviewed-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Henrique Carvalho <henrique.carvalho@suse.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Pull vfs fixes from Christian Brauner:
"This contains a fixes for the current development cycle. Note that AI
related review sometimes delays fixes a bit because we find more fixes
for the fixes. I might try and send smaller but more fixes PRs if this
trend keeps up.
- Fix various netfslib bugs
- Fix an out-of-bounds write when listing idmappings
- Fix the return values in jfs_mkdir() and orangefs_mkdir()
- Fix a writeback writeback array overflow in fuse
- Fix a forced iversion increment on lazytime timestamp updates
- Reject a negative timeval component in kern_select()
- Fix error return when vfs_mkdir() fails in the cachefiles code
- Fix wrong error code returned for pidns ioctls"
* tag 'vfs-7.1-rc5.fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (31 commits)
cachefiles: Fix error return when vfs_mkdir() fails
afs: Fix the locking used by afs_get_link()
netfs, afs: Fix write skipping in dir/link writepages
netfs: Fix netfs_read_folio() to wait on writeback
netfs: Fix folio->private handling in netfs_perform_write()
netfs: Fix partial invalidation of streaming-write folio
netfs: Fix potential UAF in netfs_unlock_abandoned_read_pages()
netfs: Fix leak of request in netfs_write_begin() error handling
netfs: Fix early put of sink folio in netfs_read_gaps()
netfs: Fix write streaming disablement if fd open O_RDWR
netfs: Fix read-gaps to remove netfs_folio from filled folio
netfs: Fix potential deadlock in write-through mode
netfs: Fix streaming write being overwritten
netfs: Defer the emission of trace_netfs_folio()
netfs: Fix netfs_invalidate_folio() to clear dirty bit if all changes gone
netfs: Fix overrun check in netfs_extract_user_iter()
netfs: fix error handling in netfs_extract_user_iter()
netfs: Fix potential uninitialised var in netfs_extract_user_iter()
netfs: fix VM_BUG_ON_FOLIO() issue in netfs_write_begin() call
netfs: Fix zeropoint update where i_size > remote_i_size
...
SMB2 READ response validation in cifs_readv_receive() and
handle_read_data() checks data_offset + data_len against the received
buffer length. Both values are attacker-controlled fields from the
server response and are stored as unsigned int, so the addition can
wrap before the bounds check:
fs/smb/client/transport.c:1259
if (!use_rdma_mr && (data_offset + data_len > buflen))
fs/smb/client/smb2ops.c:4839
else if (buf_len >= data_offset + data_len)
A malicious SMB server can use this to bypass validation. In the
non-encrypted receive path the client attempts an oversized socket
read and stalls for the SMB response timeout (180 seconds) before
reconnecting. In the SMB3 encrypted path, runtime testing shows the
malformed length can reach copy_to_iter() in handle_read_data() with
attacker-controlled size, where usercopy hardening stops the oversized
copy before bytes reach userspace.
Guard both call sites with check_add_overflow(), which is already
used elsewhere in this subsystem (smb2pdu.c). On overflow, treat the
response as malformed and reject with -EIO.
Signed-off-by: Jeremy Erazo <mendozayt13@gmail.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
On 32-bit architectures, the infinite loop is as follows:
len = p->ErrorDataLength == 0xfffffff8
u8 *next = p->ErrorContextData + len
next == p
On 32-bit architectures, the out-of-bounds read is as follows:
len = p->ErrorDataLength == 0xfffffff0
u8 *next = p->ErrorContextData + len
next == (u8 *)p - 8
Reported-by: ChenXiaoSong <chenxiaosong@kylinos.cn>
Fixes: 76894f3e2f ("cifs: improve symlink handling for smb2+")
Cc: stable@vger.kernel.org
Signed-off-by: Ye Bin <yebin10@huawei.com>
Reviewed-by: ChenXiaoSong <chenxiaosong@kylinos.cn>
Signed-off-by: Steve French <stfrench@microsoft.com>
