It could be useful to trace Windows users activity in a Samba server share environment. Let's see how to get username, ip address, hostname, file and operation type in our log file thanks to vfs module.
Fr
[global]
workgroup = WORKGROUP
server string = serv
bind interfaces only = yes
vfs objects = full_audit
full_audit:prefix = %u|%I|%m|%S
#full_audit:success = mkdir rename unlink rmdir pwrite #For samba version < 4.17
full_audit:success = mkdirat renameat unlinkat pwrite #For samba version < 4.17
full_audit:failure = none
full_audit:facility = local7
full_audit:priority = NOTICE
root@host:~# testparm
root@host:~# smbcontrol all reload-config
###############
#### RULES ####
###############
#
# First some standard log files. Log by facility.
#
auth,authpriv.* /var/log/auth.log
#*.*;auth,authpriv.none -/var/log/syslog
# local7.none prevent to have local7 facility log inside syslog file
*.*;auth,authpriv.none;local7.none -/var/log/syslog
#cron.* /var/log/cron.log
daemon.* -/var/log/daemon.log
kern.* -/var/log/kern.log
lpr.* -/var/log/lpr.log
mail.* -/var/log/mail.log
user.* -/var/log/user.log
#samba log will be sent to /var/log/samba_vfs.log file
local7.* /var/log/samba_vfs.log
[…]
#we disable local7 logs to /var/log/messages
*.=info;*.=notice;*.=warn;\
auth,authpriv.none;\
cron,daemon.none;\
mail.none;local7.none -/var/log/messages
root@host:~# systemctl restart rsyslog
root@host:~# tail -f /var/log/samba_vfs.log
Full audit mode is pretty verbose, so the file log is gonna be huge very quickly. So I developed a script to manage it.
⚠️Works for ext4 file system only.
#! /bin/bash
SDE=$(/bin/date --date='2 days ago' +%s) #two days epoch
INO=$(stat -c %i /var/log/samba_vfs.log) #get inode number of /var/log/samba_vfs.log file
DEV=/dev/sda1 #device where /var has been mounted
CRE=$(/bin/date --date="$(/sbin/debugfs -R 'stat <"'"$INO"'">' $DEV 2>/dev/null | grep 'crtime:' | sed 's/.*-- //')" +%s) #get epoch time of last /var/log/samba_vfs.log modification
A=6
B=7
if [ "$SDE" -gt "$CRE" ]; then
while [ "$A" -ge 1 ]; do
mv /var/log/samba_vfs."$A".gz /var/log/samba_vfs."$B".gz
((A-=1)) #ou A=$((A-1))
((B-=1))
done
gzip -c /var/log/samba_vfs.log > /var/log/samba_vfs.1.gz
rm /var/log/samba_vfs.log
systemctl restart rsyslog
fi
0 3 * * * root /usr/local/sbin/log_samba.sh
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