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https://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs.git
# Conflicts:
# fs/bpf_fs_kfuncs.c
# tools/testing/selftests/filesystems/.gitignore
# tools/testing/selftests/filesystems/Makefile
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check_lock_range() uses inclusive ranges. Its callers pass the end
offset as start + length - 1, so start == end represents a valid
single-byte range rather than an empty range.
The start == end shortcut therefore skips mandatory byte-range lock
checks for one-byte reads, writes, copychunk operations and one-byte
truncate ranges. A conflicting lock covering that byte is not checked
and the operation is allowed to proceed.
Remove the shortcut. The truncate size == inode->i_size case is already
handled by only calling check_lock_range() when the new size differs
from the current file size.
Fixes: 5d510ac31626 ("ksmbd: skip lock-range check on equal size to avoid size==0 underflow")
Signed-off-by: Guangshuo Li <lgs201920130244@gmail.com>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
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The query-info buffer check returns STATUS_INFO_LENGTH_MISMATCH for
every output buffer smaller than the complete response. Variable-length
filesystem information instead requires STATUS_BUFFER_OVERFLOW when the
fixed portion fits but the complete data does not.
Pass the fixed size for each filesystem information class to the buffer
checker. Keep INFO_LENGTH_MISMATCH for buffers below that size, and
return BUFFER_OVERFLOW with a response truncated to the requested length
for larger partial buffers.
This fixes smb2.getinfo.qfs_buffercheck.
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
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Named streams are stored as extended attributes on the base inode. The
VFS read and write helpers reject directory inodes before or together
with checking whether the handle represents a stream.
Permit read and write operations when a directory-backed handle is a
named stream. Continue rejecting direct I/O on ordinary directory
handles.
This fixes creation of the directory stream in smb2.getinfo.complex.
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
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SMB clients can currently create an EA named NTACL because SMB EAs are
mapped into the user namespace while the ksmbd security descriptor is
stored as security.NTACL. Allowing the reserved logical name makes the
server-private ACL metadata appear writable through the SMB EA API.
Reject NTACL, DOSATTRIB, and DosStream-prefixed EA names without regard
to case. Filter the same private names from EA query results so stale or
externally-created user namespace attributes cannot be exposed.
This fixes smb2.ea.acl_xattr when acl_xattr_name is configured as
NTACL.
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
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DELETE_ON_CLOSE is currently accepted for files carrying the read-only
DOS attribute. The server consequently creates or opens the file and
marks it for deletion instead of returning STATUS_CANNOT_DELETE.
Reject creation of a new read-only file with DELETE_ON_CLOSE. For an
existing file, load the stored DOS attributes before accepting the
create option. Also reject FileDispositionInformation when the opened
file has the read-only attribute.
Preserve the explicit STATUS_CANNOT_DELETE value while unwinding the
CREATE request.
This fixes smb2.delete-on-close-perms.READONLY.
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
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The SMB2 create maximal-access context is currently calculated from
POSIX mode bits when the client does not request MAXIMUM_ALLOWED. This
overwrites the access granted by a stored Windows DACL.
Calculate the create-context result with the DACL permission checker.
Recognize the S-1-3-4 Owner Rights SID as applying to the object owner
and process its allow and deny ACEs in ACL order.
When an Owner Rights ACE is present, do not add the owner implicit
READ_CONTROL and WRITE_DAC rights. The Owner Rights ACE replaces those
implicit grants as required by Windows access-check semantics.
Without an Owner Rights ACE, preserve the existing implicit owner grants,
including FILE_READ_ATTRIBUTES and DELETE.
This fixes smb2.acls.OWNER-RIGHTS and its deny variants without regressing
smb2.acls.GENERIC.
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
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SMB shares can advertise access-based directory enumeration. ksmbd does
not currently provide a share option or filter inaccessible directory
entries.
Add a hide-unreadable share flag and advertise
SMB2_SHAREFLAG_ACCESS_BASED_DIRECTORY_ENUM when it is enabled. During
QUERY_DIRECTORY, omit entries unless the connected user has
FILE_READ_DATA, FILE_READ_EA, and FILE_READ_ATTRIBUTES access according
to the Windows ACL.
Keep the existing implicit access allowances for normal CREATE
permission checks while using strict access-mask matching for directory
enumeration.
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
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The DACL permission check looks for an ACE matching the current user and
falls back to the Everyone ACE. It does not consider an Authenticated
Users ACE, even though an authenticated session is a member of that
well-known group.
As a result, opening a file whose access is granted through S-1-5-11 can
incorrectly fail with STATUS_ACCESS_DENIED. Treat an Authenticated Users
ACE as a fallback entry alongside Everyone.
The maximal access calculation also combines access masks from every ACE,
regardless of whether its SID applies to the current user. This can grant
rights belonging to an unrelated principal. Process only ACEs applying to
the user, Everyone, or Authenticated Users, and accumulate allowed and
denied masks in ACL order. Preserve explicitly requested access bits so
they are validated against the resulting maximal mask.
When ACCESS_SYSTEM_SECURITY is denied, report STATUS_PRIVILEGE_NOT_HELD
instead of the generic STATUS_ACCESS_DENIED. Access to the system ACL
requires a security privilege that ksmbd does not grant.
For regular files, include FILE_EXECUTE in maximal access when the client
requested GENERIC_EXECUTE and the DACL grants the complete file-read set.
Keep a direct FILE_EXECUTE request subject to the explicit DACL bit. This
matches the POSIX file ACL mapping without broadening specific execute
requests.
Do not replace rights from an applicable NT ACE with a POSIX ACL entry.
The POSIX ACL is only a fallback when no user, Everyone, or Authenticated
Users ACE applies; otherwise it can incorrectly broaden the stored DACL.
This fixes smb2.maximum_allowed.maximum_allowed.
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
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An SMB2 WRITE request with a negative offset returns -EINVAL directly
from smb2_write(). This bypasses the common error response path, leaving
the client waiting until the request times out.
ksmbd also allows nonempty writes at or beyond MAXFILESIZE as defined by
[MS-FSA]. Writes beyond the limit must fail with
STATUS_INVALID_PARAMETER. Writes ending at the limit fail with
STATUS_DISK_FULL, while a zero-length write remains valid.
Route negative offsets through the common error path and validate the end
offset of nonempty writes against MAXFILESIZE.
This fixes smb2.rw.invalid.
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
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SMB3.1.1 multichannel connections belonging to the same session must use
the same negotiated encryption cipher.
ksmbd validates the dialect and client GUID during session binding, but
does not compare the cipher negotiated by the new connection with the
cipher used by the existing session channels. This allows a channel
negotiated with AES-128-CCM to bind to a session using AES-128-GCM.
Compare the new connection's cipher with an existing session channel and
return STATUS_INVALID_PARAMETER when they differ.
This fixes smb2.session.bind_negative_smb3encGtoCs.
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
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ksmbd_decompress_request() bounds the decompressed size only against
the maximum request size. A compression transform can therefore
produce a buffer smaller than an SMB2 PDU and install it as
conn->request_buf.
The receive path subsequently calls ksmbd_smb_request(), which reads
the protocol ID before the normal SMB2 minimum-size check. If the
decompressed output is too short, that read can access beyond the
request allocation.
Require the decompressed output to contain at least a complete minimum
SMB2 PDU before allocating and installing the replacement request
buffer.
Fixes: a08de24c2b85 ("ksmbd: negotiate and decode SMB2 compression")
Cc: stable@vger.kernel.org
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
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The receive path applies the minimum SMB2 PDU size check only when
ProtocolId is SMB2_PROTO_NUMBER. A packet carrying
SMB2_TRANSFORM_PROTO_NUM bypasses the check even when the negotiated
dialect does not provide transform handling.
On an SMB 2.1 connection, a short transform packet therefore reaches
init_smb2_rsp_hdr(), which interprets the request as a full SMB2 header
and reads beyond the request allocation. The copied fields can then be
returned to the unauthenticated client.
Compression transforms are converted to ordinary SMB2 messages before
protocol validation. After that conversion, validate ordinary SMB2
requests against SMB2_MIN_SUPPORTED_PDU_SIZE and require encryption
transform requests to contain both a transform header and an SMB2
header. This rejects truncated requests before work allocation.
Fixes: 368ba06881c3 ("ksmbd: check the validation of pdu_size in ksmbd_conn_handler_loop")
Cc: stable@vger.kernel.org
Reported-by: zdi-disclosures@trendmicro.com # ZDI-CAN-31063
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
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In ntlm_authenticate(), destroy_previous_session() is called using a
user pointer resolved from the client-supplied NTLM blob username field
before the NTLMv2 response is validated. An authenticated attacker can
set the NTLM blob username to match a victim account and set
PreviousSessionId to the victim's session ID; destroy_previous_session()
destroys the victim's session while ksmbd_decode_ntlmssp_auth_blob()
subsequently rejects the request with -EPERM.
Move destroy_previous_session() and the prev_id assignment to after
ksmbd_decode_ntlmssp_auth_blob() returns success and use sess->user
rather than the pre-authentication lookup result. This matches the
ordering already used by krb5_authenticate(), where
destroy_previous_session() is called only after
ksmbd_krb5_authenticate() returns success.
Fixes: e2f34481b24d ("cifsd: add server-side procedures for SMB3")
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/linux-cifs/20260702155449.3639773-1-james_montgomery@disroot.org/
Signed-off-by: James Montgomery <james_montgomery@disroot.org>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
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set_ntacl_dacl() validates sid.num_subauth before copying an ACE, but
does not verify that the declared ACE size contains all sub-authorities
described by that field. An undersized ACE can therefore be copied
and later make the POSIX ACL deduplication walk inspect data beyond
the copied ACE boundary.
The existing initial bound check is also too small. It only ensures
that the ACE size field is accessible before set_ntacl_dacl() reads
sid.num_subauth farther into the input buffer.
Require enough input for the fixed SID header before accessing
num_subauth, reject ACEs smaller than that header, and skip ACEs
whose declared size cannot contain the complete SID. This makes the
validation consistent with the other ACE walk paths.
Reported-by: LocalHost <localhost.detect@gmail.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
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check_add_overflow() unconditionally writes the truncated sum into *d
even on overflow, per its contract in include/linux/overflow.h.
The four check_add_overflow() guards in set_posix_acl_entries_dacl()
and set_ntacl_dacl() break out of the ACE-building loops on overflow,
but the truncated *size is then consumed downstream at the end of
set_ntacl_dacl():
pndacl->size = cpu_to_le16(le16_to_cpu(pndacl->size) + size);
This produces an on-wire NT ACL whose pndacl->size under-reports the
bytes actually written by the preceding fill_ace_for_sid()/memcpy()
calls, yielding a malformed ACL that can trigger out-of-bounds reads
when re-parsed by clients or ksmbd itself.
Restore *size to its pre-addition value on each overflow branch (via
`*size -= ace_sz` / `size -= nt_ace_size`) so that after the break,
*size once again holds the cumulative size of the successfully-written
ACEs. The committed ACL is then truncated-but-self-consistent rather
than malformed.
The ksmbd DACL builders are the only check_add_overflow() sites found
where an overflow path breaks out of a loop and the destination value
is consumed afterward. The other nearby break-style cases either
return -EINVAL on overflow (transport_ipc.c) or break without
consuming the overflowed destination value afterward (buildid.c).
Fixes: 299f962c0b02 ("ksmbd: use check_add_overflow() to prevent u16 DACL size overflow")
Assisted-by: atomcode:glm-5.2
Assisted-by: Codex:gpt-5.5
Cc: stable@vger.kernel.org
Signed-off-by: Wentao Guan <guanwentao@uniontech.com>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
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set_ntacl_dacl() can stop copying ACEs before consuming the full input
DACL when size accounting overflows.
When that happens, num_aces reflects only the ACEs that were actually
copied into the output DACL, but set_posix_acl_entries_dacl() still
receives nt_num_aces and uses it to walk the existing ACE array during
dedup.
That makes the dedup walk scan past the copied ACE array and inspect
buffer tail that does not contain valid ACEs.
Split the two meanings currently carried by the NT ACE count. Pass the
number of copied NT ACEs to bound the dedup walk, and preserve the
original "input DACL had NT ACEs" state separately for the
Everyone/default ACL fallback.
This keeps the dedup walk aligned with the ACEs that are actually
present in the rebuilt DACL.
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
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This fallback function CIFSSMBSetPathInfoFB() is called only from
CIFSSMBSetPathInfo() function. CIFSSMBSetPathInfo() is used in
smb_set_file_info() which contains all required fallback code, including
fallback via filehandle, since commit f122121796f9 ("cifs: Fix changing
times and read-only attr over SMB1 smb_set_file_info() function") and
commit 92210ccd877b ("cifs: Add fallback code path for cifs_mkdir_setinfo()").
So the CIFSSMBSetPathInfoFB() is just code duplication, which is not needed
anymore. Therefore remove it.
Signed-off-by: Pali Rohár <pali@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
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Do not call SMBQueryInformation() command for path with SMB wildcard
characters on non-UNICODE connection because server expands wildcards.
Function cifs_is_path_accessible() needs to check if the real path exists
and must not expand wildcard characters.
Do not dynamically allocate memory for small FILE_ALL_INFO structure and
instead allocate it on the stack. This structure is allocated on stack by
all other functions.
When CAP_NT_SMBS was not negotiated then do not issue CIFSSMBQPathInfo()
command. This command returns failure by non-NT Win9x SMB servers, so there
is no need try it. The purpose of cifs_is_path_accessible() function is
just to check if the path is accessible, so SMBQueryInformation() for old
servers is enough.
Signed-off-by: Pali Rohár <pali@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
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When modefromsid is active, parse_dacl() applies the server-provided
sub_auth[2] value from the NFS mode SID to cf_mode without masking to
07777. Apply the correct masking, same as in the read path.
Fixes: e2f8fbfb8d09c ("cifs: get mode bits from special sid on stat")
Signed-off-by: Norbert Manthey <nmanthey@amazon.de>
Assisted-by: Kiro:claude-opus-4.6
Cc: stable@vger.kernel.org
Signed-off-by: Steve French <stfrench@microsoft.com>
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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>
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Reproducer:
1. mount -t cifs //${server_ip}/export /mnt
2. touch /mnt/file1; ln /mnt/file1 /mnt/file2; ln /mnt/file1 /mnt/file3
3. C program: int fd = open("/mnt/file1", O_RDONLY);
4. C program: struct stat stbuf; fstat(fd, &stbuf);
stbuf.st_nlink is always 1, should be 3
Setting `unknown_nlink` to true in `SMB2_open()` triggers the
`CIFS_FATTR_UNKNOWN_NLINK` flag in `cifs_open_info_to_fattr()`,
which safely preserves the existing i_nlink in
`cifs_nlink_fattr_to_inode()`.
See the detailed procedure below:
path_openat
open_last_lookups
lookup_open
atomic_open
cifs_atomic_open // dir->i_op->atomic_open
cifs_lookup
cifs_get_inode_info
cifs_get_fattr
smb2_query_path_info // server->ops->query_path_info
smb2_compound_op
SMB2_open_init
case SMB2_OP_QUERY_INFO
SMB2_query_info_init(FILE_ALL_INFORMATION,)
cifs_open_info_to_fattr
fattr->cf_nlink = le32_to_cpu(info->NumberOfLinks)
update_inode_info
cifs_iget
cifs_fattr_to_inode
cifs_nlink_fattr_to_inode
set_nlink(inode, fattr->cf_nlink)
do_open
vfs_open
do_dentry_open
cifs_open
cifs_nt_open
smb2_open_file // server->ops->open
SMB2_open
buf->unknown_nlink = true
cifs_get_inode_info
cifs_get_fattr
cifs_open_info_to_fattr
if (data->unknown_nlink) // true
fattr->cf_flags |= CIFS_FATTR_UNKNOWN_NLINK
update_inode_info
cifs_fattr_to_inode
cifs_nlink_fattr_to_inode
if (fattr->cf_flags & CIFS_FATTR_UNKNOWN_NLINK) // true
return // do not modify nlink
Signed-off-by: ChenXiaoSong <chenxiaosong@kylinos.cn>
Signed-off-by: Steve French <stfrench@microsoft.com>
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Stack-allocated cifs_open_info_data may contain random data.
This can make some fields have wrong value if they are not set later.
Signed-off-by: ChenXiaoSong <chenxiaosong@kylinos.cn>
Signed-off-by: Steve French <stfrench@microsoft.com>
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Let SMB2_open() fill the smb2_file_all_info embedded in cifs_open_info_data
directly. This removes the temporary smb2_file_all_info copy in
smb2_open_file().
Signed-off-by: ChenXiaoSong <chenxiaosong@kylinos.cn>
Signed-off-by: Steve French <stfrench@microsoft.com>
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SMB2_open() only fills the fixed fields, so a stack-allocated
smb2_file_all_info is sufficient here.
Signed-off-by: ChenXiaoSong <chenxiaosong@kylinos.cn>
Signed-off-by: Steve French <stfrench@microsoft.com>
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smb2_ioctl_query_info() validates the PASSTHRU_FSCTL response payload
before copying it to userspace.
The payload offset and length both come from 32-bit fields. The bounds
check currently adds OutputOffset and qi.input_buffer_length directly, so
the addition can wrap in 32-bit arithmetic before the result is compared
against the response buffer length.
A malicious server can use a large OutputOffset and a small OutputCount
to make the wrapped sum pass the bounds check. The later copy_to_user()
then reads from io_rsp + OutputOffset, outside the response buffer.
Use size_add() for the offset plus length check so overflow is treated as
out of bounds.
Fixes: 2b1116bbe898 ("CIFS: Use common error handling code in smb2_ioctl_query_info()")
Signed-off-by: Guangshuo Li <lgs201920130244@gmail.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
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Commit c68337442f03 ("cifs: Fix busy dentry used after unmounting") fixed
the issue in cifs where deferred close of a file led to a dentry reference
count not being released in umount, by flushing deferredclose_wq in
cifs_kill_sb() to solve it.
However, the cifs DIO path suffers from the same busy-dentry problem caused
by a delayed dentry reference-count release:
[dio] [cifsd] [close + umount]
netfs_unbuffered_write_iter_locked
...
cifs_demultiplex_thread
netfs_unbuffered_write
cifs_issue_write
netfs_wait_for_in_progress_stream [1]
...
netfs_write_subrequest_terminated
netfs_subreq_clear_in_progress
netfs_wake_collector // wake [1]
netfs_put_subrequest
netfs_put_request
queue_work(system_dfl_wq, xxx) [2]
// dio write return cifs_close
_cifsFileInfo_put
// cfile->count 2->1
--cfile->count [3]
// umount
cifs_kill_sb
kill_anon_super
// warning triggered!
shrink_dcache_for_umount [4]
[system_dfl_wq] [5]
netfs_free_request
...
_cifsFileInfo_put
// cfile->count 1->0
--cfile->count
queue_work(fileinfo_put_wq, xxx)
[fileinfo_put_wq] [6]
cifsFileInfo_put_work
cifsFileInfo_put_final
dput
If the umount path is triggered before [5], it results warning:
BUG: Dentry 00000000eab1f070{i=9a917b66ae404fec,n=test} still in use (1)
[unmount of cifs cifs]
The existing per-inode ictx->io_count wait in cifs_evict_inode() does not
help: it lives in the inode eviction path, which runs after
shrink_dcache_for_umount() has already warned about the busy dentries.
Fix it by adding a per-superblock outstanding-rreq counter that is
incremented in cifs_init_request() and decremented in cifs_free_request().
In cifs_kill_sb(), before kill_anon_super(), wait for this counter to reach
0 - which guarantees that all cleanup_work for this sb have run and thus
all relevant cfile puts are queued on fileinfo_put_wq or serverclose_wq.
Then drain the workqueue so the dentry refs are dropped.
This is a targeted wait, not a flush of the system-wide system_dfl_wq.
Fixes: 340cea84f691c ("cifs: open files should not hold ref on superblock")
Signed-off-by: Zizhi Wo <wozizhi@huawei.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
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SFU fifos are natively supported (created and recognized) at least by:
- Microsoft POSIX subsystem
- OpenNT/Interix subsystem
- Microsoft SFU (Windows Services for UNIX)
- Microsoft SUA (Subsystem for UNIX-based Applications)
- Windows NFS server (up to the Windows Server 2008 R2)
Windows NFS server since Windows Server 2012 uses new reparse point format
for storing new fifos, but still can recognize this old format (also in the
latest Windows Server 2022 version).
SFU-style fifo is empty regular file which has system attribute set.
These SFU-style fifos are already recognized by Linux SMB client.
But Linux SMB client is currently creating new SFU fifos in different
format which is not compatible with all those SFU-style consumers. Fix this
by creating new fifos in correct SFU format which would be recognized by
all those applications and also by existing Linux SMB clients.
This change affects only creating new fifos when mount option -o sfu is used.
Signed-off-by: Pali Rohár <pali@kernel.org>
Acked-by: Paulo Alcantara (Red Hat) <pc@manguebit.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
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SFU sockets are natively supported by Interix 3.0 subsystem and also by
later versions. It is part of Microsoft SFU (Windows Services for UNIX) and
Microsoft SUA (Subsystem for UNIX-based Applications). They can be created
and existing (stored on local disk or remote SMB share) can be recognized.
SFU sockets are recognized also by NFS server included in Windows Server.
Windows NFS server versions since Windows Server 2012 uses new reparse
point format for storing new sockets, but still can recognize this old
format (also in the latest Windows Server 2022 version).
SFU-style socket is a regular file which has system attribute set and
content of the file is one zero byte.
These SFU-style sockets are already recognized by Linux SMB client.
But Linux SMB client is currently creating new SFU socket in different
format which is not compatible with all those SFU applications. Fix this by
creating new sockets in correct SFU format which would be recognized by all
SFU, SUA, NFS and existing Linux SMB clients.
This change affects only creating new sockets when mount option -o sfu is used.
Signed-off-by: Pali Rohár <pali@kernel.org>
Acked-by: Paulo Alcantara (Red Hat) <pc@manguebit.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
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cifs_rreq_done() updates the inode atime to current_time(inode) after a
netfs read. It then preserves the CIFS rule that atime should not be
older than mtime, because some applications break if atime is less than
mtime. That rule only requires clamping when atime < mtime.
The current check uses the raw non-zero result of timespec64_compare().
It therefore takes the clamp path for both atime < mtime and
atime > mtime. The latter is the normal case when reading an older file:
the newly recorded atime is newer than the file mtime. The completion
handler then immediately moves atime back to mtime, losing the access
time that was just recorded. Userspace tools that rely on atime, such as
stat, find -atime, backup tools or cold-data classifiers, can therefore
see a recently read CIFS file as not recently accessed.
This is easy to miss because the bug is silent: read I/O still succeeds,
no error is reported, and many systems either do not check atime after
reads or mount with policies such as relatime/noatime. It becomes
visible when a CIFS file has an mtime older than the current time, the
file is read, and the local inode atime is inspected before a later
revalidation replaces the cached timestamps.
Clamp only when atime is actually older than mtime. This matches the
same atime/mtime rule used when applying CIFS inode attributes.
Fixes: 69c3c023af25 ("cifs: Implement netfslib hooks")
Cc: stable@vger.kernel.org
Signed-off-by: Xu Rao <raoxu@uniontech.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
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parse_dfs_referrals() validates that the response header and referral
array fit in the received buffer, but each referral also contains string
offsets supplied by the server.
Those offsets are used to compute the DfsPath and NetworkAddress string
pointers without checking whether they still point inside the response
buffer. A malformed referral can therefore make the computed pointer
exceed the end of the buffer. The resulting negative max_len is then
passed to cifs_strndup_from_utf16(), and the non-Unicode path forwards it
to kstrndup() as a size_t, allowing strnlen() to read out of bounds.
Validate each string offset before deriving the string pointer.
Fixes: 4ecce920e13a ("CIFS: move DFS response parsing out of SMB1 code")
Signed-off-by: Guangshuo Li <lgs201920130244@gmail.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
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In dfs_cache.c, the helper functions alloc_target(), setup_referral(),
and update_cache_entry_locked() currently utilize GFP_ATOMIC to
allocate memory.
However, all of these functions are executed in sleepable conditions.
Use GFP_KERNEL instead, to reduce the risk of allocation failure and
stop putting unnecessary pressure on emergency memory pools in
low-memory scenarios.
Signed-off-by: Fredric Cover <fredric.cover.lkernel@gmail.com>
Acked-by: Paulo Alcantara (Red Hat) <pc@manguebit.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
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smb2_check_message() has a long-standing quirk that accepts a response
whose calculated length is one byte larger than the bytes actually
received ("server can return one byte more due to implied bcc[0]").
This was introduced to accommodate servers that omit the trailing bcc[0]
overlap byte when no data area is present.
However, the exemption is applied unconditionally, regardless of whether
the command actually carries a data area (has_smb2_data_area[]). When a
response with a data area is subject to the +1 exemption, the reported
data can extend one byte beyond the bytes actually received, yet
smb2_check_message() still accepts it. The subsequent decoder then reads
past the end of the receive buffer. This is reachable during NEGOTIATE
and SESSION_SETUP, before the session is established.
The resulting out-of-bounds reads are visible under KASAN when mounting
against a non-conforming server; both the SPNEGO/negTokenInit and the
NTLMSSP challenge decoders are affected:
BUG: KASAN: slab-out-of-bounds in asn1_ber_decoder+0x16a7/0x1b00
Read of size 1 at addr ffff8880084d67c0 by task mount.cifs/81
CPU: 1 UID: 0 PID: 81 Comm: mount.cifs Not tainted 7.1.0-rc6 #1
Call Trace:
<TASK>
dump_stack_lvl+0x4e/0x70
print_report+0x157/0x4c9
kasan_report+0xce/0x100
asn1_ber_decoder+0x16a7/0x1b00
decode_negTokenInit+0x19/0x30
SMB2_negotiate+0x31d9/0x4c90
cifs_negotiate_protocol+0x1f2/0x3f0
cifs_get_smb_ses+0x93f/0x17e0
cifs_mount_get_session+0x7f/0x3a0
cifs_mount+0xb4/0xcf0
cifs_smb3_do_mount+0x23a/0x1500
smb3_get_tree+0x3b0/0x630
vfs_get_tree+0x82/0x2d0
fc_mount+0x10/0x1b0
path_mount+0x50d/0x1de0
__x64_sys_mount+0x20b/0x270
do_syscall_64+0xee/0x590
entry_SYSCALL_64_after_hwframe+0x77/0x7f
</TASK>
Allocated by task 85:
kmem_cache_alloc_noprof+0x106/0x380
mempool_alloc_noprof+0x116/0x1e0
cifs_small_buf_get+0x31/0x80
allocate_buffers+0x10d/0x2b0
cifs_demultiplex_thread+0x1d5/0x1d50
kthread+0x2c6/0x390
ret_from_fork+0x36e/0x5a0
ret_from_fork_asm+0x1a/0x30
The buggy address is located 0 bytes to the right of
allocated 448-byte region [ffff8880084d6600, ffff8880084d67c0)
which belongs to the cache cifs_small_rq of size 448
BUG: KASAN: slab-out-of-bounds in kmemdup_noprof+0x36/0x50
Read of size 329 at addr ffff88800726c678 by task mount.cifs/89
CPU: 0 UID: 0 PID: 89 Comm: mount.cifs Tainted: G B 7.1.0-rc6 #1
Call Trace:
<TASK>
dump_stack_lvl+0x4e/0x70
print_report+0x157/0x4c9
kasan_report+0xce/0x100
kasan_check_range+0x10f/0x1e0
__asan_memcpy+0x23/0x60
kmemdup_noprof+0x36/0x50
decode_ntlmssp_challenge+0x457/0x680
SMB2_sess_auth_rawntlmssp_negotiate+0x6f0/0xcb0
SMB2_sess_setup+0x219/0x4f0
cifs_setup_session+0x248/0xaf0
cifs_get_smb_ses+0xf79/0x17e0
cifs_mount_get_session+0x7f/0x3a0
cifs_mount+0xb4/0xcf0
cifs_smb3_do_mount+0x23a/0x1500
smb3_get_tree+0x3b0/0x630
vfs_get_tree+0x82/0x2d0
fc_mount+0x10/0x1b0
path_mount+0x50d/0x1de0
__x64_sys_mount+0x20b/0x270
do_syscall_64+0xee/0x590
entry_SYSCALL_64_after_hwframe+0x77/0x7f
</TASK>
Allocated by task 93:
kmem_cache_alloc_noprof+0x106/0x380
mempool_alloc_noprof+0x116/0x1e0
cifs_small_buf_get+0x31/0x80
allocate_buffers+0x10d/0x2b0
cifs_demultiplex_thread+0x1d5/0x1d50
kthread+0x2c6/0x390
ret_from_fork+0x36e/0x5a0
ret_from_fork_asm+0x1a/0x30
The buggy address is located 120 bytes inside of
allocated 448-byte region [ffff88800726c600, ffff88800726c7c0)
which belongs to the cache cifs_small_rq of size 448
Restrict the +1 exemption to responses that have no data area, so that
it still covers the bcc[0] omission it was meant for. When a data area
is present, the +1 discrepancy instead means the reported data length
overruns the received buffer, so the response must be rejected.
Fixes: 093b2bdad322 ("CIFS: Make demultiplex_thread work with SMB2 code")
Cc: stable@vger.kernel.org
Signed-off-by: Shoichiro Miyamoto <shoichiro.miyamoto@gmail.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
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|
Signed-off-by: Christian Brauner <brauner@kernel.org>
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When creating a native SMB symbolic link (CIFS_SYMLINK_TYPE_NATIVE) whose
target is an absolute path on a mount that uses POSIX paths, the leading
path separator was silently dropped from the stored symlink target.
create_native_symlink() converted the target to UTF-16 with
cifs_convert_path_to_utf16(). That helper was intended for share-relative
SMB paths and therefore unconditionally strips a leading path separator.
For an absolute POSIX symlink target the leading '/' is significant, so a
target of "/foo/bar" was stored and read back as "foo/bar", even
though the reparse point was still flagged as absolute
(SYMLINK_FLAG_RELATIVE cleared).
On a POSIX paths mount the symlink target is stored verbatim, so convert
it directly with cifs_strndup_to_utf16() instead. This preserves the
leading separator, avoids the leading-backslash stripping that
cifs_convert_path_to_utf16() also performs (a backslash is a valid POSIX
filename character), and uses NO_MAP_UNI_RSVD to match the readback path
in smb2_parse_native_symlink(), which always converts the target with
cifs_strndup_from_utf16() / NO_MAP_UNI_RSVD. This mirrors how the NFS and
WSL reparse symlink creators convert their targets.
The NT-style absolute symlink handling, which needs the "\??\" prefix and
drive-letter colon preserved, continues to use cifs_convert_path_to_utf16()
together with the existing masking of those bytes.
Fixes: 12b466eb52d9 ("cifs: Fix creating and resolving absolute NT-style symlinks")
Reviewed-by: Paulo Alcantara (Red Hat) <pc@manguebit.org>
Acked-by: Ralph Boehme <slow@samba.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
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When an SMB3 session is referenced by a binding request on an SMB2.1
connection, the request is signed with the existing session's SMB3 signing
algorithm. ksmbd instead verifies it with the new connection's SMB2.1 HMAC
algorithm, so verification fails and the client receives
STATUS_ACCESS_DENIED instead of STATUS_REQUEST_NOT_ACCEPTED.
Select the signing verifier from the referenced session dialect. Permit a
signed SESSION_SETUP without an established channel to use the SMB3 session
signing key for verification. This is limited to SESSION_SETUP so other
unbound requests remain rejected.
The rejected response must use the same existing session algorithm. When an
SMB3 session is referenced on an SMB2.1 connection, sign the SESSION_SETUP
response with the SMB3 signing path rather than the connection's SMB2.1
path.
This fixes smb2.session.bind_negative_smb3to2s.
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
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Binding an SMB 2.1 session to an SMB 3.x connection is invalid because the
dialects do not match. ksmbd returns STATUS_INVALID_PARAMETER. The check
fails before attaching the referenced session to the request, so the error
response lacks SMB2_FLAGS_SIGNED.
A client requiring signing checks this flag before handling the status and
reports STATUS_ACCESS_DENIED instead of STATUS_INVALID_PARAMETER. Preserve
the signed flag for a signed binding request rejected with
STATUS_INVALID_PARAMETER. The client can then apply the special error path
without attempting to validate a response using incompatible signing
algorithms.
This fixes smb2.session.bind_negative_smb2to3s.
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
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SMB2_SESSION_REQ_FLAG_BINDING is not supported before SMB 3.0. ksmbd maps
such a request to STATUS_REQUEST_NOT_ACCEPTED, but it rejects the request
without looking up the referenced session. The response is then sent
unsigned. A client requiring signing reports
STATUS_ACCESS_DENIED instead of the server status.
Look up the referenced session and verify the binding request with its
signing key. Keep the session reference only after successful verification
so the rejected response can be signed without providing a signing oracle.
A signed SESSION_SETUP without the binding flag can reference a session
that does not belong to the connection. Preserve SMB2_FLAGS_SIGNED on the
STATUS_USER_SESSION_DELETED response. Clients skip signature verification
for this status but still require the signed flag before propagating it.
Also restrict failed binding preauthentication cleanup to SMB 3.1.1, the
only dialect that initializes and uses that context.
This fixes smb2.session.bind_negative_smb210s.
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
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When an authenticated user tries to bind a channel to a session owned by a
different user, ksmbd returns STATUS_LOGON_FAILURE. Windows instead rejects
this attempt with STATUS_ACCESS_DENIED. The supplied credentials are valid
but cannot be used with the existing session.
Use a distinct internal error for a user mismatch in both NTLM and Kerberos
authentication and map it to STATUS_ACCESS_DENIED during SESSION_SETUP.
Keep ordinary authentication failures mapped to STATUS_LOGON_FAILURE.
A failed SMB 3.1.1 binding also leaves its preauthentication context on the
connection. A subsequent binding attempt for the same session reuses the
stale hash and derives an incorrect channel signing key. Remove the binding
preauthentication context on failure so a valid retry starts with a fresh
hash.
This fixes smb2.session.bind_different_user.
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
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|
A session bound to an additional connection is stored in the session
channel list, but it is not added to that connection's local session table.
After the binding exchange completes, conn->binding is cleared.
A later SESSION_SETUP reauthentication on the bound channel only searches
the local session table. It fails to find the session and returns
STATUS_USER_SESSION_DELETED instead of processing authentication and
returning STATUS_LOGON_FAILURE for invalid credentials.
If the local lookup fails, look up the session globally and accept it only
when the current connection is registered in its channel list. This keeps
unbound connections from using the session while allowing reauthentication
on an established channel.
This fixes smb2.session.bind_invalid_auth.
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
|
|
When a signed request uses a session that is not registered on the
connection, ksmbd returns STATUS_USER_SESSION_DELETED before reaching the
normal response signing path. The response therefore lacks
SMB2_FLAGS_SIGNED.
Clients that require signing check this flag before handling
STATUS_USER_SESSION_DELETED and replace the server status with
STATUS_ACCESS_DENIED when it is absent. The protocol permits this error
response to skip signature verification because the connection has no
matching session key.
Preserve SMB2_FLAGS_SIGNED on the early error response when the request was
signed. This lets the client propagate STATUS_USER_SESSION_DELETED.
It fixes smb2.session.bind2.
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
|
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FILE_ALLOCATION_INFORMATION can call vfs_fallocate(). If the allocation
cannot be satisfied, vfs_fallocate() returns -ENOSPC.
smb2_set_info() did not map -ENOSPC, so ksmbd returned a generic SMB error
and the client reported EIO instead of ENOSPC. This makes the ENOSPC step
in xfstests generic/213 fail.
Map -ENOSPC and -EFBIG to STATUS_DISK_FULL in the SET_INFO error path.
Tested with xfstests generic/213 on ksmbd.
Signed-off-by: Huiwen He <hehuiwen@kylinos.cn>
Reviewed-by: ChenXiaoSong <chenxiaosong@kylinos.cn>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
|
|
Windows reports automatic write-time updates with a resolution of roughly
15 milliseconds. If a file is written and closed within that interval, a
close response requesting full information can report the write time from
the open rather than the filesystem's finer-grained mtime update.
ksmbd currently converts the filesystem mtime directly in SMB2 CLOSE, so
even a sub-millisecond write is visible to the client. This makes
smb2.timestamp_resolution.resolution1 fail because the immediate write
changes LastWriteTime.
Save the write time returned by SMB2 CREATE in the file handle. When CLOSE
requests post-query attributes, coalesce a positive mtime change smaller
than 15 milliseconds to that saved value. Larger changes remain visible,
including the test's write after a 20 millisecond delay.
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
|
|
A signed multichannel SESSION_SETUP binding request can require multiple
authentication rounds. ksmbd excludes SESSION_SETUP from the signed
request check and tries to sign every binding response with the channel
signing key. The channel does not exist for
STATUS_MORE_PROCESSING_REQUIRED, so that response is sent unsigned.
Clients reject it with STATUS_ACCESS_DENIED.
The final channel signing key also needs the key exported by the binding
authentication context. Keep that key in the channel instead of
overwriting the established session key, and use the session signing key
for intermediate and failed binding responses. Retain the binding session
reference until an error response has been signed and sent.
Limit a session to 32 channels while holding the channel lock. Return
STATUS_INSUFFICIENT_RESOURCES for an additional binding, matching the
server limit expected by clients.
This fixes smb2.multichannel.generic.num_channels, which previously
failed the first binding with STATUS_ACCESS_DENIED and returned the same
status instead of STATUS_INSUFFICIENT_RESOURCES for channel 33.
Fixes: f5a544e3bab7 ("ksmbd: add support for SMB3 multichannel")
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
|
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sid_to_id() currently treats the last subauthority of any owner or group
SID as a Unix uid or gid. For example, this maps Everyone (S-1-1-0) to
uid 0 and BUILTIN\Users (S-1-5-32-545) to gid 545.
When an SMB2 CREATE security descriptor contains those SIDs, ksmbd
attempts to change the newly created file to the bogus Unix ownership.
notify_change() then returns -EPERM, which makes smb2.create.aclfile fail
with NT_STATUS_SHARING_VIOLATION.
Validate the SID prefix before extracting its RID. Only server-domain
owner SIDs and S-1-22-2 Unix group SIDs have local ID representations.
Treat other valid Windows SIDs as unmapped so their original values can
still be preserved in the NT ACL xattr.
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
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In the `skip_invalidate:` path under `cifs_revalidate_mapping()`, the
sequence of calls:
clear_bit_unlock();
smp_mb__after_atomic();
wake_up_bit();
can be replaced exactly by `clear_and_wake_up_bit()`.
The `clear_and_wake_up_bit()` helper function was introduced in
'commit 8236b0ae31c83 ("bdi: wake up concurrent wb_shutdown()
callers.")' to replace equivalent instances of this sequence of
operations. This substitution has been applied in multiple subsystems.
Compile-tested with CONFIG_CIFS=y on x86_64, no new warnings present.
Suggested-by: Agatha Isabelle Moreira <code@agatha.dev>
Link: https://kernelnewbies.org/Beginner%20Cleanup%20and%20Refactor%20Tasks%20by%20Agatha%20Isabelle%20Moreira#task_010
Cc: Agatha Isabelle Moreira <code@agatha.dev>
Signed-off-by: Mehdi Hassan <mehdi.h.business@pm.me>
Signed-off-by: Steve French <stfrench@microsoft.com>
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Pull smb server fixes from Steve French:
- Fix several use-after-free races in durable handle reconnect,
supersede, and oplock handling
- Avoid holding the inode oplock lock while waiting for a lease break
acknowledgement. This removes delays of up to 35 seconds when cifs.ko
closes a deferred handle in response to a lease break
- Fix malformed security descriptor handling, including an undersized
DACL allocation issue and an out-of-bounds ACE SID read
- Fix memory leaks in security descriptor and DOS attribute xattr
encoding/decoding error paths
- Fix outstanding SMB2 credit leaks on aborted requests and correct the
QUERY_INFO credit charge calculation
- Fix hard-link creation without replacement being incorrectly rejected
when the handle lacks DELETE access
- Avoid unnecessary zeroing of large SMB2 read buffers
- Add an oplock list lockdep annotation and update the documented
support status for durable handles and SMB3.1.1 compression
- Durable handle fixes to address ownership and lifetime races during
reconnect, session teardown, oplock handling, and superseding opens,
preventing stale session and file references from being used by
concurrent operations
* tag 'v7.2-rc1-smb3-server-fixes' of git://git.samba.org/ksmbd:
ksmbd: fix app-instance durable supersede session UAF
ksmbd: snapshot previous oplock state before durable checks
ksmbd: close superseded durable handles through refcount handoff
ksmbd: fix use-after-free of fp->owner.name in durable handle owner check
smb/server: do not require delete access for non-replacing links
ksmbd: don't hold ci->m_lock while waiting for a lease break ack
ksmbd: doc: update feature support status for durable handles and compression
ksmbd: annotate oplock list traversals under m_lock
ksmbd: fix outstanding credit leak on abort and error paths
ksmbd: fix credit charge calculation for SMB2 QUERY_INFO
ksmbd: avoid zeroing the read buffer in smb2_read()
ksmbd: validate num_subauth when copying ACE in set_ntacl_dacl
ksmbd: reject undersized DACLs before parsing ACEs
ksmbd: fix n.data memory leak in ksmbd_vfs_set_dos_attrib_xattr
ksmbd: Fix acl.sd_buf memory leak and invalid sd_size error handling
ksmbd: fix sd_ndr.data memory leak in ksmbd_vfs_set_sd_xattr
|
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Fix missing release of credits in the failure path in cifs_issue_read()
lest retrying the subreq just overwrites the credits value.
Fixes: 69c3c023af25 ("cifs: Implement netfslib hooks")
Link: https://sashiko.dev/#/patchset/20260608145432.681865-1-dhowells%40redhat.com
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Paulo Alcantara (Red Hat) <pc@manguebit.org>
cc: linux-cifs@vger.kernel.org
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Steve French <stfrench@microsoft.com>
|
