I am not sure it is legal to require signing and to connect as guest.
See quote from protocol specification (MS-SMB2):
If the SMB2_SESSION_FLAG_IS_GUEST bit is set in the SessionFlags field
of the SMB2
SESSION_SETUP Response and if Session.SigningRequired is TRUE, this indicates a
SESSION_SETUP failure and the connection MUST be terminated. If the
SMB2_SESSION_FLAG_IS_GUEST bit is set in the SessionFlags field of the SMB2
SESSION_SETUP Response and if RequireMessageSigning is FALSE,
Session.SigningRequired
MUST be set to FALSE.
On Wed, Mar 20, 2019 at 1:40 PM Andreas Hasenack <andreas@xxxxxxxxxxxxx> wrote:
>
> Hi,
>
> I can't mount a share as guest using SMB2 or higher when running the
> 5.0.0 kernel (ubuntu's 5.0.0-7.8 specifically). When I switch to a
> 4.19.x kernel (4.19.0-12-generic), then it works.
>
> This is the mount command and output:
> root@ubuntu:~# mount //localhost/pub /mnt -o guest
> mount error(13): Permission denied
> Refer to the mount.cifs(8) manual page (e.g. man mount.cifs)
>
> The share is a simple one:
> [pub]
> path = /pub
> guest ok = yes
>
> The server logs this:
> [2019/03/20 18:24:46.245816, 0]
> ../../libcli/smb/smb2_signing.c:169(smb2_signing_check_pdu)
> Bad SMB2 signature for message
> [2019/03/20 18:24:46.245860, 0] ../../lib/util/util.c:508(dump_data)
> [0000] 2D 60 1F CA 49 06 92 B0 69 06 60 82 42 39 21 F8 -`..I... i.`.B9!.
> [2019/03/20 18:24:46.245894, 0] ../../lib/util/util.c:508(dump_data)
> [0000] 75 F8 77 09 63 D5 4A 7B 9F 91 51 93 6D 12 6F 6F u.w.c.J{ ..Q.m.oo
>
> Here is a dmesg output with cifs debugging enabled:
> https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1821053/+attachment/5247960/+files/dmesg.txt
>
> That output was from a kernel running patch
> https://git.kernel.org/pub/scm/linux/kernel/git/stable/stable-queue.git/tree/queue-5.0/cifs-do-not-skip-smb2-message-ids-on-send-failures.patch,
> just a quick attempt to see if that fixed it, but it didn't.
>
> mount.cifs is version 6.8
>
> Server is samba 4.10.0.
>
> Is this a known issue?
>
> Thanks!
--
Thanks,
Steve
