[Pkg-samba-maint] Bug#1019545: samba: Permission/ownership issue in /var/lib/samba results in repeated panic or segfault after upgrading from Buster to Bullseye
Jason Cohen
jasonwc.server at gmail.com
Sun Sep 11 17:28:23 BST 2022
Package: samba
Version: 2:4.16.4+dfsg-2~bpo11+1
Severity: normal
Dear Maintainer,
*** Reporter, please consider answering these questions, where appropriate ***
* What led up to the situation?
I upgraded my system from Buster to Bullseye. As part of that process, Samba was upgraded to 4.16.4. After the upgrade, I began receiving emails reporting a Panic or segfault in Samba everytime a user tried to access a file share after going idle.
* What exactly did you do (or not do) that was effective (or
ineffective)?
After enabling debug logging, I saw that the panic/segfault was preceeded by the following error:L "stat of /var/lib/samba/usershare/data failed. Permission denied."
In order to fix the issue, I changed the file ownership of all files in the above directory to root:sambashare and added my user (jason) to the sambashare group. After making these changes, the errors went away. I am reporting this as it's a change in behavior. I did not experience these segfaults in Buster. It appears that the expected ownership of this directory changed, causing my issue.
* What was the outcome of this action?
Changing the ownership to root:sambashare and adding my user to the sambashare group resolved the segfaults.
* What outcome did you expect instead?
-- Package-specific info:
* /etc/samba/smb.conf present, and attached
* /var/lib/samba/dhcp.conf present, and attached
-- System Information:
Debian Release: 11.5
APT prefers stable-updates
APT policy: (500, 'stable-updates'), (500, 'stable-security'), (500, 'stable')
Architecture: amd64 (x86_64)
Kernel: Linux 5.10.0-17-amd64 (SMP w/32 CPU threads)
Kernel taint flags: TAINT_PROPRIETARY_MODULE, TAINT_OOT_MODULE, TAINT_UNSIGNED_MODULE
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8) (ignored: LC_ALL set to en_US.UTF-8), LANGUAGE=en_US.UTF-8
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled
Versions of packages samba depends on:
ii adduser 3.118
ii init-system-helpers 1.60
ii libbsd0 0.11.3-1
ii libc6 2.31-13+deb11u4
ii libcups2 2.3.3op2-3+deb11u2
ii libgnutls30 3.7.1-5+deb11u2
ii libldap-2.4-2 2.4.57+dfsg-3+deb11u1
ii libldb2 2:2.5.2+samba4.16.4-2~bpo11+1
ii libpam-modules 1.4.0-9+deb11u1
ii libpam-runtime 1.4.0-9+deb11u1
ii libpopt0 1.18-2
ii libtalloc2 2.3.3-4~bpo11+1
ii libtasn1-6 4.16.0-2
ii libtdb1 1.4.6-3~bpo11+1
ii libtevent0 0.11.0-1~bpo11+1
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 2:4.16.4+dfsg-2~bpo11+1
ii samba-common 2:4.16.4+dfsg-2~bpo11+1
ii samba-common-bin 2:4.16.4+dfsg-2~bpo11+1
ii samba-libs 2:4.16.4+dfsg-2~bpo11+1
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+deb11u1
ii python3-markdown 3.3.4-1
ii samba-dsdb-modules 2:4.16.4+dfsg-2~bpo11+1
ii samba-vfs-modules 2:4.16.4+dfsg-2~bpo11+1
Versions of packages samba suggests:
ii bind9 1:9.16.27-1~deb11u1
ii bind9-utils [bind9utils] 1:9.16.27-1~deb11u1
ii bind9utils 1:9.16.27-1~deb11u1
ii ctdb 2:4.16.4+dfsg-2~bpo11+1
pn ldb-tools <none>
ii ntp 1:4.2.8p15+dfsg-1
pn smbldap-tools <none>
pn ufw <none>
pn winbind <none>
-- Configuration Files:
/etc/logrotate.d/samba changed:
/var/log/samba/log.smbd {
weekly
missingok
rotate 7
postrotate
[ ! -x /usr/bin/smbcontrol ] || [ ! -f /run/samba/smbd.pid ] || /usr/bin/smbcontrol smbd reload-config
endscript
#compress
delaycompress
notifempty
}
/var/log/samba/log.nmbd {
weekly
missingok
rotate 7
postrotate
[ ! -x /usr/bin/smbcontrol ] || [ ! -f /run/samba/nmbd.pid ] || /usr/bin/smbcontrol nmbd reload-config
endscript
#compress
delaycompress
notifempty
}
/var/log/samba/log.samba {
weekly
missingok
rotate 7
postrotate
if [ -d /run/systemd/system ] && command systemctl >/dev/null 2>&1 && systemctl is-active --quiet samba-ad-dc; then
systemctl kill --kill-who all --signal=SIGHUP samba-ad-dc
elif [ -f /run/samba/samba.pid ]; then
# This only sends to main pid, See #803924
kill -HUP `cat /run/samba/samba.pid`
fi
endscript
#compress
delaycompress
notifempty
}
-- debconf information:
samba/run_mode: daemons
samba-common/title:
-------------- 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]
log file = /var/log/samba/log.%m
log level = 3
passwd chat = *Enter\snew\s*\spassword:* %n\n *Retype\snew\s*\spassword:* %n\n *password\supdated\ssuccessfully* .
server role = standalone server
obey pam restrictions = yes
map to guest = bad user
passwd program = /usr/bin/passwd %u
passdb backend = tdbsam
dns proxy = no
unix password sync = yes
workgroup = WORKGROUP
# syslog = 0
panic action = /usr/share/samba/panic-action %d
usershare allow guests = yes
max log size = 1000
pam password change = yes
server multi channel support = yes
interfaces = "fd98:4179:d465:1::200;capability=RSS,speed=40000000000"
## Browsing/Identification ###
# Change this to the workgroup/NT-domain name your Samba server will part of
# 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.
#### 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 eth0
# 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
# Cap the size of the individual log files (in KiB).
# If you want Samba to only log through syslog then set the following
# parameter to 'yes'.
# syslog only = no
# We want Samba to log a minimum amount of information to syslog. Everything
# should go to /var/log/samba/log.{smbd,nmbd} instead. If you want to log
# through syslog you should set the following parameter to something higher.
# Do something sensible when Samba crashes: mail the admin a backtrace
####### 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.
# If you are using encrypted passwords, Samba will need to know what
# password database type you are using.
# 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.
# 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).
# 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'.
# This option controls how unsuccessful authentication attempts are mapped
# to anonymous connections
########## Domains ###########
#
# The following settings only takes effect if 'server role = primary
# classic domain controller', 'server role = 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
#======================= Share Definitions =======================
[homes]
comment = Home Directories
browseable = no
# By default, the home directories are exported read-only. Change the
# next parameter to 'no' if you want to be able to write to them.
read only = yes
# File creation mask is set to 0700 for security reasons. If you want to
# create files with group=rw permissions, set next parameter to 0775.
create mask = 0700
# Directory creation mask is set to 0700 for security reasons. If you want to
# create dirs. with group=rw permissions, set next parameter to 0775.
directory mask = 0700
# By default, \\server\username shares can be connected to by anyone
# with access to the samba server.
# The following parameter makes sure that only "username" can connect
# to \\server\username
# This might need tweaking when using external authentication schemes
valid users = %S
# Un-comment the following and create the netlogon directory for Domain Logons
# (you need to configure Samba to act as a domain controller too.)
;[netlogon]
; comment = Network Logon Service
; path = /home/samba/netlogon
; guest ok = yes
; read only = yes
# Un-comment the following and create the profiles directory to store
# users profiles (see the "logon path" option above)
# (you need to configure Samba to act as a domain controller too.)
# The path below should be writable by all users so that their
# profile directory may be created the first time they log on
;[profiles]
; comment = Users profiles
; path = /home/samba/profiles
; guest ok = no
; browseable = no
; create mask = 0600
; directory mask = 0700
#[printers]
# comment = All Printers
# browseable = no
# path = /var/spool/samba
# printable = yes
# guest ok = no
# read only = yes
# create mask = 0700
[Television]
comment = Television
path = /data/Television
guest ok = yes
read only = yes
# optlocks = false
# level2 oplocks = false
[Movies]
comment = Movies
path = /data/Movies
guest ok = yes
read only = yes
# optlocks = false
# level2 oplocks = false
[Justin-Data]
comment = Justin-Data
path = "/data/downloads/Justin Data"
guest ok = yes
read only = no
[Ting-Documents]
comment = Ting-Documents
path = "/data/documents/Ting's Documents"
guest ok = yes
read only = no
[Ting-Photos]
comment = Ting-Photos
path = "/data/photos/Ting's Photos"
guest ok = yes
read only = no
[Ting-Downloads]
comment = Ting-Downloads
path = "/data/downloads/Ting's Downloads"
guest ok = yes
read only = no
# Windows clients look for this share name as a source of downloadable
# printer drivers
#[print$]
# comment = Printer Drivers
# path = /var/lib/samba/printers
# browseable = yes
# read only = yes
# guest ok = no
# Uncomment to allow remote administration of Windows print drivers.
# You may need to replace 'lpadmin' with the name of the group your
# admin users are members of.
# Please note that you also need to set appropriate Unix permissions
# to the drivers directory for these users to have write rights in it
; write list = root, @lpadmin
[IntelSSD]
comment = IntelSSD
path = "/mnt/intel/share"
guest ok = yes
read only = no
[VM-Ting]
writeable = yes
public = yes
path = /data/VMs
[VM-Secret]
writeable = yes
valid users = jason,ting
create mode = 777
path = /data/VMs
write list = jason,ting
directory mode = 777
[photos]
writeable = yes
public = yes
path = /data/photos
[Software]
writeable = yes
public = yes
path = /data/Software/
#[data_VFS]
# path = /data
# read only = No
# comment = ZFS dataset with Previous Versions enabled
# shadow: snapdir = .zfs/snapshot
# shadow: sort = desc
# shadow: format = zrepl_%Y%m%d_%H%M%s_000
# vfs objects = shadow_copy2
#[data_documents_VFS]
# path = /data/documents
# read only = No
# comment = ZFS dataset with Previous Versions enabled
# shadow: snapdir = .zfs/snapshot
# shadow: sort = desc
# shadow: format = zrepl_%Y%m%d_%H%M%s_000
# vfs objects = shadow_copy2
#[data_backups_VFS]
# path = /data/backups
# read only = No
# comment = ZFS dataset with Previous Versions enabled
# shadow: snapdir = .zfs/snapshot
# shadow: sort = desc
# shadow: format = zrepl_%Y%m%d_%H%M%s_000
# vfs objects = shadow_copy2
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