[Pkg-samba-maint] Bug#999545: samba: definition of %H suddenly changed in recent security update 4.13.13+dfsg-1~deb11u2.

Cameron Davidson bugs at davidsoncj.id.au
Fri Nov 12 07:45:36 GMT 2021


Package: samba
Version: 2:4.13.13+dfsg-1~deb11u2
Severity: normal

Dear Maintainer,

I have samba ad-dc running on a Debian 10 system, and recently updated
my secondary file server to Debian 11. (at which stage it went to samba 4.13.5+dfsg-2)
The AD-DC is still running Deb 10.

All was working OK, but today I did security update 2:4.13.13+dfsg-1~deb11u2.
Two issues emerged, the first of which must have been my mistake, and
the 2nd is the subject of this report. By the way, this is just a home system and
has evolved this way for historical reasons.

After restart of smbd, no shares worked, and the log files were
complaining about missing winbindd. Somehow it previously worked without
it, but now required it, so I installed and started winbindd and some shares started
working.

However, any shares defined implicitly or explicitly by the "%H" macro failed.
Log files showed it was attempting to share /home/DAVIDSON/username where
DAVIDSON is the workgroup name from the config file. (this system until recently
was supporting some very old windows machines)

So it seems the value of %H has changed from being /home/%U to
/home/%D/%U

I could work around the issue by explicitly specifying an appropriate path
that did not use %H. Then the remaining shares started working as expected.

I could find no mention of this change in the README, nor in the
changelog nor in the smb.conf man page.

Thanks for listening.

-- Package-specific info:
* /etc/samba/smb.conf present, and attached
* /var/lib/samba/dhcp.conf not present

shares.cfg is included from smb.conf and relevant parts are:

[homes]
        comment = Unix Home Directories
        read only = No

[HomeDir]
        comment = Home Directories
        %H/Windows
        read only = No
        inherit permissions = Yes
        browseable = Yes




-- System Information:
Debian Release: 11.1
  APT prefers stable-security
  APT policy: (500, 'stable-security'), (500, 'stable')
Architecture: amd64 (x86_64)

Kernel: Linux 5.10.0-9-amd64 (SMP w/6 CPU threads)
Locale: LANG=en_AU.UTF-8, LC_CTYPE=en_AU.UTF-8 (charmap=UTF-8), LANGUAGE=en_AU:en
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)

Versions of packages samba depends on:
ii  adduser              3.118
ii  dpkg                 1.20.9
ii  init-system-helpers  1.60
ii  libbsd0              0.11.3-1
ii  libc6                2.31-13+deb11u2
ii  libgnutls30          3.7.1-5
ii  libldb2              2:2.2.3-2~deb11u1
ii  libpam-modules       1.4.0-9+deb11u1
ii  libpam-runtime       1.4.0-9+deb11u1
ii  libpopt0             1.18-2
ii  libpython3.9         3.9.2-1
ii  libtalloc2           2.3.1-2+b1
ii  libtasn1-6           4.16.0-2
ii  libtdb1              1.4.3-1+b1
ii  libtevent0           0.10.2-1
ii  libwbclient0         2:4.13.13+dfsg-1~deb11u2
ii  lsb-base             11.1.0
ii  procps               2:3.3.17-5
ii  python3              3.9.2-3
ii  python3-dnspython    2.0.0-1
ii  python3-samba        2:4.13.13+dfsg-1~deb11u2
ii  samba-common         2:4.13.13+dfsg-1~deb11u2
ii  samba-common-bin     2:4.13.13+dfsg-1~deb11u2
ii  samba-libs           2:4.13.13+dfsg-1~deb11u2
ii  tdb-tools            1.4.3-1+b1

Versions of packages samba recommends:
ii  attr                1:2.4.48-6
ii  logrotate           3.18.0-2
ii  python3-markdown    3.3.4-1
ii  samba-dsdb-modules  2:4.13.13+dfsg-1~deb11u2
ii  samba-vfs-modules   2:4.13.13+dfsg-1~deb11u2

Versions of packages samba suggests:
ii  bind9                     1:9.16.22-1~deb11u1
ii  bind9-utils [bind9utils]  1:9.16.22-1~deb11u1
ii  bind9utils                1:9.16.22-1~deb11u1
pn  ctdb                      <none>
pn  ldb-tools                 <none>
ii  ntp                       1:4.2.8p15+dfsg-1
pn  smbldap-tools             <none>
pn  ufw                       <none>
ii  winbind                   2:4.13.13+dfsg-1~deb11u2

-- no debconf information

-- debsums errors found:
debsums: changed file /usr/share/doc/samba/NEWS.Debian.gz (from samba package)
debsums: changed file /usr/share/doc/samba/changelog.Debian.gz (from samba package)
-------------- next part --------------
#
# Sample configuration file for the Samba suite for Debian GNU/Linux.
#
#
# This is the main Samba configuration file. You should read the
# smb.conf(5) manual page in order to understand the options listed
# here. Samba has a huge number of configurable options most of which 
# are not shown in this example
#
# Some options that are often worth tuning have been included as
# commented-out examples in this file.
#  - When such options are commented with ";", the proposed setting
#    differs from the default Samba behaviour
#  - When commented with "#", the proposed setting is the default
#    behaviour of Samba but the option is considered important
#    enough to be mentioned here
#
# NOTE: Whenever you modify this file you should run the command
# "testparm" to check that you have not made any basic syntactic 
# errors. 

#======================= Global Settings =======================

[global]
	security = ADS
	workgroup = DAVIDSON
	realm = AD.DAVIDSONCJ.ID.AU
	server string = Davidson file Server
	#interfaces = lo, eth0, eth1, tun0
	interfaces = lo, xenbrlan, xenbrw
	bind interfaces only = Yes
	pam password change = No
	log level = 1
	log file = /var/log/samba/%m.log
	max log size = 2000
	server min protocol = SMB2_10
	server max protocol = SMB3
	#max protocol = NT1
	#client signing = auto
	#client ipc signing = auto
	os level = 33
	preferred master = Yes
	local master = No
	domain master = Auto
	dns proxy = No
	wins support = No
	winbind nss info = rfc2307
	# Default ID mapping configuration for local BUILTIN accounts
	# and groups on a domain member. The default (*) domain:
	# - must not overlap with any domain ID mapping configuration!
	# - must use a read-write-enabled back end, such as tdb.
	idmap config * : backend = tdb
	idmap config * : range = 60001-70000
	idmap config DAVIDSON : backend = ad
	idmap config DAVIDSON : range = 1000-59000
	idmap config DAVIDSON : unix_primary_group = yes
	invalid users = ftp, http, sync, shutdown, halt, xfs, named, squid
	#hosts allow = ::1 2406:3400:41e:1af2::/112 127. 192.168.92. 172.17.92. 192.168.93. 2406:3400:41e:1af3::/112
	hosts allow = ::1 2406:3400:41e:1af2::/112 127. 192.168.92. 172.17.92.
	browseable = No
	unix extensions = No
	wide links = Yes
	delete readonly = Yes

	# we have no sharable printers, so don't look for them
	load printers = No

	vfs objects = acl_xattr
	map acl inherit = yes
	store dos attributes = no

## Browsing/Identification ###

# Change this to the workgroup/NT-domain name your Samba server will part of
#   workgroup = WORKGROUP

# Windows Internet Name Serving Support Section:
# WINS Support - Tells the NMBD component of Samba to enable its WINS Server
#   wins support = no

# WINS Server - Tells the NMBD components of Samba to be a WINS Client
# Note: Samba can be either a WINS Server, or a WINS Client, but NOT both
;   wins server = w.x.y.z

# This will prevent nmbd to search for NetBIOS names through DNS.
   dns proxy = no

#### Networking ####

# The specific set of interfaces / networks to bind to
# This can be either the interface name or an IP address/netmask;
# interface names are normally preferred
interfaces = 127.0.0.0/8 ::1 xenbrlan 

# Only bind to the named interfaces and/or networks; you must use the
# 'interfaces' option above to use this.
# It is recommended that you enable this feature if your Samba machine is
# not protected by a firewall or is a firewall itself.  However, this
# option cannot handle dynamic or non-broadcast interfaces correctly.
bind interfaces only = yes



#### Debugging/Accounting ####

# This tells Samba to use a separate log file for each machine
# that connects
   log file = /var/log/samba/log.%m

# Cap the size of the individual log files (in KiB).
   max log size = 1000

# We want Samba to only log to /var/log/samba/log.{smbd,nmbd}.
# Append syslog at 1 if you want important messages to be sent to syslog too.
   logging = file

# Do something sensible when Samba crashes: mail the admin a backtrace
   panic action = /usr/share/samba/panic-action %d


####### Authentication #######

# Server role. Defines in which mode Samba will operate. Possible
# values are "standalone server", "member server", "classic primary
# domain controller", "classic backup domain controller", "active
# directory domain controller". 
#
# Most people will want "standalone sever" or "member server".
# Running as "active directory domain controller" will require first
# running "samba-tool domain provision" to wipe databases and create a
# new domain.
   server role = member server

   #obey pam restrictions = yes

# This boolean parameter controls whether Samba attempts to sync the Unix
# password with the SMB password when the encrypted SMB password in the
# passdb is changed.
   #unix password sync = yes

# For Unix password sync to work on a Debian GNU/Linux system, the following
# parameters must be set (thanks to Ian Kahan <<kahan at informatik.tu-muenchen.de> for
# sending the correct chat script for the passwd program in Debian Sarge).
   #passwd program = /usr/bin/passwd %u
   #passwd chat = *Enter\snew\s*\spassword:* %n\n *Retype\snew\s*\spassword:* %n\n *password\supdated\ssuccessfully* .

# This boolean controls whether PAM will be used for password changes
# when requested by an SMB client instead of the program listed in
# 'passwd program'. The default is 'no'.
   #pam password change = yes

# This option controls how unsuccessful authentication attempts are mapped
# to anonymous connections
   map to guest = bad user

########## Domains ###########

#
# The following settings only takes effect if 'server role = classic
# primary domain controller', 'server role = classic backup domain controller'
# or 'domain logons' is set 
#

# It specifies the location of the user's
# profile directory from the client point of view) The following
# required a [profiles] share to be setup on the samba server (see
# below)
;   logon path = \\%N\profiles\%U
# Another common choice is storing the profile in the user's home directory
# (this is Samba's default)
#   logon path = \\%N\%U\profile

# The following setting only takes effect if 'domain logons' is set
# It specifies the location of a user's home directory (from the client
# point of view)
;   logon drive = H:
#   logon home = \\%N\%U

# The following setting only takes effect if 'domain logons' is set
# It specifies the script to run during logon. The script must be stored
# in the [netlogon] share
# NOTE: Must be store in 'DOS' file format convention
;   logon script = logon.cmd

# This allows Unix users to be created on the domain controller via the SAMR
# RPC pipe.  The example command creates a user account with a disabled Unix
# password; please adapt to your needs
; add user script = /usr/sbin/adduser --quiet --disabled-password --gecos "" %u

# This allows machine accounts to be created on the domain controller via the 
# SAMR RPC pipe.  
# The following assumes a "machines" group exists on the system
; add machine script  = /usr/sbin/useradd -g machines -c "%u machine account" -d /var/lib/samba -s /bin/false %u

# This allows Unix groups to be created on the domain controller via the SAMR
# RPC pipe.  
; add group script = /usr/sbin/addgroup --force-badname %g

############ Misc ############

# Using the following line enables you to customise your configuration
# on a per machine basis. The %m gets replaced with the netbios name
# of the machine that is connecting
;   include = /home/samba/etc/smb.conf.%m

# Some defaults for winbind (make sure you're not using the ranges
# for something else.)
;   idmap uid = 10000-20000
;   idmap gid = 10000-20000
;   template shell = /bin/bash

# Setup usershare options to enable non-root users to share folders
# with the net usershare command.

# Maximum number of usershare. 0 (default) means that usershare is disabled.
;   usershare max shares = 100

# Allow users who've been granted usershare privileges to create
# public shares, not just authenticated ones
   usershare allow guests = no

#======================= Share Definitions =======================

include = /etc/samba/shares.conf


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