Commit Graph

20 Commits

Author SHA1 Message Date
Piyush Sachdeva
5be7a0cef3 smb: client: Use FullSessionKey for AES-256 encryption key derivation
When Kerberos authentication is used with AES-256 encryption (AES-256-CCM
or AES-256-GCM), the SMB3 encryption and decryption keys must be derived
using the full session key (Session.FullSessionKey) rather than just the
first 16 bytes (Session.SessionKey).

Per MS-SMB2 section 3.2.5.3.1, when Connection.Dialect is "3.1.1" and
Connection.CipherId is AES-256-CCM or AES-256-GCM, Session.FullSessionKey
must be set to the full cryptographic key from the GSS authentication
context. The encryption and decryption key derivation (SMBC2SCipherKey,
SMBS2CCipherKey) must use this FullSessionKey as the KDF input. The
signing key derivation continues to use Session.SessionKey (first 16
bytes) in all cases.

Previously, generate_key() hardcoded SMB2_NTLMV2_SESSKEY_SIZE (16) as the
HMAC-SHA256 key input length for all derivations. When Kerberos with
AES-256 provides a 32-byte session key, the KDF for encryption/decryption
was using only the first 16 bytes, producing keys that did not match the
server's, causing mount failures with sec=krb5 and require_gcm_256=1.

Add a full_key_size parameter to generate_key() and pass the appropriate
size from generate_smb3signingkey():
 - Signing: always SMB2_NTLMV2_SESSKEY_SIZE (16 bytes)
 - Encryption/Decryption: ses->auth_key.len when AES-256, otherwise 16

Also fix cifs_dump_full_key() to report the actual session key length for
AES-256 instead of hardcoded CIFS_SESS_KEY_SIZE, so that userspace tools
like Wireshark receive the correct key for decryption.

Cc: <stable@vger.kernel.org>
Reviewed-by: Bharath SM <bharathsm@microsoft.com>
Signed-off-by: Piyush Sachdeva <psachdeva@microsoft.com>
Signed-off-by: Piyush Sachdeva <s.piyush1024@gmail.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2026-05-07 14:09:01 -05:00
Paulo Alcantara
4fc3a433c1 smb: client: use atomic_t for mnt_cifs_flags
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>
2026-02-26 18:17:08 -06:00
Linus Torvalds
bf4afc53b7 Convert 'alloc_obj' family to use the new default GFP_KERNEL argument
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>
2026-02-21 17:09:51 -08:00
Kees Cook
69050f8d6d treewide: Replace kmalloc with kmalloc_obj for non-scalar types
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>
2026-02-21 01:02:28 -08:00
David Howells
ed1e53796f cifs: SMB1 split: Split SMB1 protocol defs into smb1pdu.h
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>
2026-02-08 17:07:45 -06:00
Steve French
bc31161162 smb3 client: add missing tracepoint for unsupported ioctls
In debugging a recent problem with an xfstest, noticed that we weren't
tracing cases where the ioctl was not supported.  Add dynamic tracepoint:
    "trace-cmd record -e smb3_unsupported_ioctl"
and then after running an app which calls unsupported ioctl,
"trace-cmd show"would display e.g.
      xfs_io-7289    [012] .....  1205.137765: smb3_unsupported_ioctl: xid=19 fid=0x4535bb84 ioctl cmd=0x801c581f

Acked-by: Bharath SM <bharathsm@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2025-12-30 09:16:45 -06:00
Bharath SM
27e9d5d021 smb: minor fix to use SMB2_NTLMV2_SESSKEY_SIZE for auth_key size
Replaced hardcoded value 16 with SMB2_NTLMV2_SESSKEY_SIZE
in the auth_key definition and memcpy call.

Reviewed-by: Paulo Alcantara (Red Hat) <pc@manguebit.org>
Signed-off-by: Bharath SM <bharathsm@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2025-06-21 11:03:25 -05:00
Al Viro
9bd812744d convert cifs_ioctl_copychunk()
fdput() moved past mnt_drop_file_write(); harmless, if somewhat cringeworthy.
Reordering could be avoided either by adding an explicit scope or by making
mnt_drop_file_write() called via __cleanup.

Reviewed-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2024-11-03 01:28:07 -05:00
Linus Torvalds
f8ffbc365f struct fd layout change (and conversion to accessor helpers)
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Merge tag 'pull-stable-struct_fd' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Pull 'struct fd' updates from Al Viro:
 "Just the 'struct fd' layout change, with conversion to accessor
  helpers"

* tag 'pull-stable-struct_fd' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  add struct fd constructors, get rid of __to_fd()
  struct fd: representation change
  introduce fd_file(), convert all accessors to it.
2024-09-23 09:35:36 -07:00
Steve French
15179cf280 smb3: fix problem unloading module due to leaked refcount on shutdown
The shutdown ioctl can leak a refcount on the tlink which can
prevent rmmod (unloading the cifs.ko) module from working.

Found while debugging xfstest generic/043

Fixes: 69ca1f5755 ("smb3: add dynamic tracepoints for shutdown ioctl")
Reviewed-by: Meetakshi Setiya <msetiya@microsoft.com>
Reviewed-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2024-08-22 12:36:57 -05:00
Al Viro
1da91ea87a introduce fd_file(), convert all accessors to it.
For any changes of struct fd representation we need to
turn existing accesses to fields into calls of wrappers.
Accesses to struct fd::flags are very few (3 in linux/file.h,
1 in net/socket.c, 3 in fs/overlayfs/file.c and 3 more in
explicit initializers).
	Those can be dealt with in the commit converting to
new layout; accesses to struct fd::file are too many for that.
	This commit converts (almost) all of f.file to
fd_file(f).  It's not entirely mechanical ('file' is used as
a member name more than just in struct fd) and it does not
even attempt to distinguish the uses in pointer context from
those in boolean context; the latter will be eventually turned
into a separate helper (fd_empty()).

	NOTE: mass conversion to fd_empty(), tempting as it
might be, is a bad idea; better do that piecewise in commit
that convert from fdget...() to CLASS(...).

[conflicts in fs/fhandle.c, kernel/bpf/syscall.c, mm/memcontrol.c
caught by git; fs/stat.c one got caught by git grep]
[fs/xattr.c conflict]

Reviewed-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2024-08-12 22:00:43 -04:00
Steve French
69ca1f5755 smb3: add dynamic tracepoints for shutdown ioctl
For debugging an umount failure in xfstests generic/043 generic/044 in some
configurations, we needed more information on the shutdown ioctl which
was suspected of being related to the cause, so tracepoints are added
in this patch e.g.

  "trace-cmd record -e smb3_shutdown_enter -e smb3_shutdown_done -e smb3_shutdown_err"

Sample output:
  godown-47084   [011] .....  3313.756965: smb3_shutdown_enter: flags=0x1 tid=0x733b3e75
  godown-47084   [011] .....  3313.756968: smb3_shutdown_done: flags=0x1 tid=0x733b3e75

Tested-by: Anthony Nandaa (Microsoft) <profnandaa@gmail.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2024-08-02 10:55:49 -05:00
Paulo Alcantara
58acd1f497 smb: client: fix potential UAF in cifs_dump_full_key()
Skip sessions that are being teared down (status == SES_EXITING) to
avoid UAF.

Cc: stable@vger.kernel.org
Signed-off-by: Paulo Alcantara (Red Hat) <pc@manguebit.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2024-04-03 14:43:45 -05:00
Steve French
073dd87c8e smb3: add dynamic trace point for ioctls
It can be helpful in debugging to know which ioctls are called to better
correlate them with smb3 fsctls (and opens).  Add a dynamic trace point
to trace ioctls into cifs.ko

Here is sample output:

            TASK-PID     CPU#  |||||  TIMESTAMP  FUNCTION
               | |         |   |||||     |         |
 new-inotify-ioc-90418   [001] ..... 142157.397024: smb3_ioctl: xid=18 fid=0x0 ioctl cmd=0xc009cf0b
 new-inotify-ioc-90457   [007] ..... 142217.943569: smb3_ioctl: xid=22 fid=0x389bf5b6 ioctl cmd=0xc009cf0b

Signed-off-by: Steve French <stfrench@microsoft.com>
2024-03-10 19:36:18 -05:00
Steve French
784e0e20b4 Missing field not being returned in ioctl CIFS_IOC_GET_MNT_INFO
The tcon_flags field was always being set to zero in the information
about the mount returned by the ioctl CIFS_IOC_GET_MNT_INFO instead
of being set to the value of the Flags field in the tree connection
structure as intended.

Reviewed-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2023-11-10 09:32:04 -06:00
Steve French
de4eceab57 smb3: allow dumping session and tcon id to improve stats analysis and debugging
When multiple mounts are to the same share from the same client it was not
possible to determine which section of /proc/fs/cifs/Stats (and DebugData)
correspond to that mount.  In some recent examples this turned out to  be
a significant problem when trying to analyze performance data - since
there are many cases where unless we know the tree id and session id we
can't figure out which stats (e.g. number of SMB3.1.1 requests by type,
the total time they take, which is slowest, how many fail etc.) apply to
which mount. The only existing loosely related ioctl CIFS_IOC_GET_MNT_INFO
does not return the information needed to uniquely identify which tcon
is which mount although it does return various flags and device info.

Add a cifs.ko ioctl CIFS_IOC_GET_TCON_INFO (0x800ccf0c) to return tid,
session id, tree connect count.

Cc: stable@vger.kernel.org
Reviewed-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2023-11-10 02:00:30 -06:00
Shyam Prasad N
a171eb5cac cifs: add missing return value check for cifs_sb_tlink
Whenever a tlink is obtained by cifs_sb_tlink, we need
to check that the tlink returned is not an error.
It was missing with the last change here.

Fixes: b3edef6b9c ("cifs: allow dumping keys for directories too")
Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2023-07-26 15:41:27 -05:00
Shyam Prasad N
b3edef6b9c cifs: allow dumping keys for directories too
Dumping the enc/dec keys is a session wide operation.
And it should not matter if the ioctl was run on
a regular file or a directory.

Currently, we obtain the tcon pointer from the
cifs file handle. But since there's no dir open call
in cifs, this is not populated for dirs.

This change allows dumping of session keys using ioctl
even for directories. To do this, we'll now get the
tcon pointer from the superblock, and not from the file
handle.

Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2023-07-22 14:42:54 -05:00
Steve French
fdd7d1fff4 cifs: address unused variable warning
Fix trivial unused variable warning (when SMB1 support disabled)

"ioctl.c:324:17: warning: variable 'caps' set but not used [-Wunused-but-set-variable]"

Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202305250056.oZhsJmdD-lkp@intel.com/
Signed-off-by: Steve French <stfrench@microsoft.com>
2023-05-27 03:33:23 -05:00
Steve French
38c8a9a520 smb: move client and server files to common directory fs/smb
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>
2023-05-24 16:29:21 -05:00