[PATCH][SMB3] allow files to be created with backslash in file name

[Steve French]

I wasn't able to setup a second independent repro of this until
tonight, but the smbclient behavior (bug) does appear to be dependent
on the version of smbclient (see below).  Newer versions failed
(including current Samba, 4.14-pre and 4.12.5 Ubuntu).  These were all
attempted on the same machine, and the repro was simple. See below.

Recreation:
create two files with reserved characters (locally on the server) in
the root of the share (in this case xfs, running on the current stable
kernel,
5.10.4 although that is unlikely to matter)
$ ls /scratch
'file-\-backslash'  'file-?-question'

I also created a subdirectory with additional files with reserved
characters, although that may not matter.

$ ls /scratch/rsvd-chars
'dir-with-trailing-space '  'file-\backslash'    'file space'
 file                       'file->greaterthan'
'file-*asterisk'            'file-?question'

I exported the /scratch directory with smb.conf configured as

[scratch]
   comment = scratch share for testing
   browseable = yes
   path = /scratch
   guest ok = yes
   read only = no
   ea support = yes
   create mask = 0777
   directory mask = 0777
   vfs objects = acl_xattr
   map acl inherit = yes
   strict allocate = yes
   map acl inherit = yes
   mangled names = no

Connecting with smbclient and doing a simple ls causes the disconnect:
$ smbclient --version
Version 4.12.5-Ubuntu
$ smbclient //localhost/scratch -U testuser
Enter SAMBA\testuser's password:
Try "help" to get a list of possible commands.
smb: \> ls
  .                                   D        0  Fri Jan  1 21:19:52 2021
  ..                                  D        0  Thu Dec 31 21:42:28 2020
  rsvd-chars                          D        0  Fri Jan  1 09:14:04 2021
  file-?-question                     N        0  Fri Jan  1 21:19:42 2021
is_bad_finfo_name: bad finfo->name
NT_STATUS_INVALID_NETWORK_RESPONSE listing \*
smb: \> SMBecho failed (NT_STATUS_CONNECTION_DISCONNECTED). The
connection is disconnected now

wireshark trace shows a simple open (SMB3.1.1 create) followed by
level 37 SMB3.1.1 find request, then smbclient appears to drop the tcp
session.

Running smbclient with -d 10 (debug level) shows these three messages

dos_clean_name [\*]
unix_clean_name [\*]
is_bad_finfo_name: bad finfo->name

Trying the same thing with *older* smbclient worked, although there is
a possibility that other differences in build with the two smbclients
could be the reason that the older one worked and the newer one
failed:

$ /usr/local/samba/bin/smbclient //localhost/share --version
Version 4.11.0pre1-GIT-e63e391a1ad
$ /usr/local/samba/bin/smbclient //localhost/scratch -U testuser
smb: \> ls
  .                                   D        0  Fri Jan  1 21:19:52 2021
  ..                                  D        0  Thu Dec 31 21:42:28 2020
  rsvd-chars                          D        0  Fri Jan  1 09:14:04 2021
  file-?-question                     N        0  Fri Jan  1 21:19:42 2021
  file-\-backslash                    N        0  Fri Jan  1 21:19:52 2021

556368460 blocks of size 1024. 295948832 blocks available

I also tried it with current smbclient and it also failed:

$ ./bin/smbclient --version
Version 4.14.0pre1-DEVELOPERBUILD
$ ./bin/smbclient //localhost/scratch -U testuser
Enter SAMBA\testuser's password:
Try "help" to get a list of possible commands.
smb: \> ls
  .                                   D        0  Fri Jan  1 21:19:52 2021
  ..                                  D        0  Thu Dec 31 21:42:28 2020
  rsvd-chars                          D        0  Fri Jan  1 09:14:04 2021
  file-?-question                     N        0  Fri Jan  1 21:19:42 2021
is_bad_finfo_name: bad finfo->name
NT_STATUS_INVALID_NETWORK_RESPONSE listing \*
smb: \> SMBecho failed (NT_STATUS_CONNECTION_DISCONNECTED). The
connection is disconnected now

On Fri, Jan 1, 2021 at 8:58 PM Jeremy Allison <jra at samba.org> wrote:
>
> On Fri, Jan 01, 2021 at 05:57:08PM -0500, Steve French wrote:
> >4.12.4 Ubuntu
> >
> >On Fri, Jan 1, 2021, 14:58 Jeremy Allison <jra at samba.org> wrote:
> >> >is_bad_finfo_name: bad finfo->name
> >> >NT_STATUS_INVALID_NETWORK_RESPONSE listing \*
> >> >smb: \> SMBecho failed (NT_STATUS_CONNECTION_DISCONNECTED). The
> >> >connection is disconnected now
> >>
> >> Can you log a bug please and give full setup instructions
> >> to reproduce. This isn't enough to show me what the bug is.
> >> I need a directory listing from the Server side to show
> >> me what files are in the root of the share.
> >>
> >> Also, you neglect to tell me what Samba version you are
> >> using (which is a pre-requisite for a bug report Steve,
> >> you know this :-).
>
> To channel Rowland, this isn't a bug report, this is an
> anecdote :-).
>
> Here's what I did to show this doesn't happen.
>
> $ mkdir /tmp/chartest
> $ touch /tmp/chartest/fil\\e.dat
> $ ls -l /tmp/chartest/
> total 0
> -rw-rw-r-- 1 user user 0 Jan  1 18:52 'fil\e.dat'
>
> Edit /usr/local/samba/etc/smb.conf, add:
>
> [chartest]
>         path = /tmp/chartest
>         guest ok = yes
>         read only = no
>
> Restart smbd. Run:
>
> $ /usr/local/samba/bin/smbclient //127.0.0.1/chartest -Uuser%password -mSMB3
> smb: \> ls
>    .                                   D        0  Fri Jan  1 18:52:10 2021
>    ..                                  D        0  Fri Jan  1 18:51:38 2021
>    FI7KDO~J.DAT                        N        0  Fri Jan  1 18:52:10 2021
>
> IF YOU WANT ME TO INVESTIGATE THIS IS NEED A SIMILAR
> LEVEL OF DETAIL (sigh). But I *know* you *know*
> this...



-- 
Thanks,

Steve