[Pkg-samba-maint] Bug#856843: smbclient: connection flood to port 445 on mounting cifs volume under kernel 4.9.0
nils
internationils at gmx.net
Sun Mar 5 11:30:33 UTC 2017
Package: smbclient
Version: 2:4.2.14+dfsg-0+deb8u2
Severity: important
Hello,
after upgrading my kernel from 4.0.8 to 4.0.9 I am getting connection floods to
my FreeNAS samba server from my debian machine. I never had this issue with
4.0.8
Linux dnet64 4.9.0-0.bpo.1-amd64 #1 SMP Debian 4.9.2-2~bpo8+1 (2017-01-26)
x86_64 GNU/Linux
ii smbclient 2:4.2.14+dfsg-0+deb8u2 amd64 command-line
SMB/CIFS clients for Unix
After mouting the cifs share(s) everything is OK for about 10 minutes, then a
flood of connections happens. Here is an extract of 'netstat -an' run every
second. Only one or two connections are shown for every 'netstat -an' run. The
connections are opening and closing at an incredible speed (nethogs goes to
100% and doesn't show anything because it's overwhelmed). gkrellm reports about
70k/Sec traffic due to this. See how the source port numbers increase
increadibly quickly to get an idea of how many connections are really
happening...
....
tcp 0 1 10.0.2.15:55044 192.168.2.88:445 SYN_SENT
tcp 0 1 10.0.2.15:55252 192.168.2.88:445 SYN_SENT
tcp 0 0 10.0.2.15:55288 192.168.2.88:445 ESTABLISHED
tcp 0 1 10.0.2.15:55314 192.168.2.88:445 SYN_SENT
tcp 0 1 10.0.2.15:55348 192.168.2.88:445 SYN_SENT
tcp 0 0 10.0.2.15:55396 192.168.2.88:445 ESTABLISHED
tcp 0 1 10.0.2.15:55454 192.168.2.88:445 SYN_SENT
tcp 0 0 10.0.2.15:55500 192.168.2.88:445 ESTABLISHED
tcp 0 0 10.0.2.15:55544 192.168.2.88:445 ESTABLISHED
tcp 0 42 10.0.2.15:55586 192.168.2.88:445 ESTABLISHED
tcp 0 0 10.0.2.15:55630 192.168.2.88:445 ESTABLISHED
tcp 0 0 10.0.2.15:55676 192.168.2.88:445 ESTABLISHED
tcp 0 0 10.0.2.15:55720 192.168.2.88:445 ESTABLISHED
tcp 0 1 10.0.2.15:55770 192.168.2.88:445 SYN_SENT
tcp 1 0 10.0.2.15:55820 192.168.2.88:445 CLOSE_WAIT
tcp 0 1 10.0.2.15:55868 192.168.2.88:445 SYN_SENT
tcp 0 0 10.0.2.15:55912 192.168.2.88:445 ESTABLISHED
tcp 0 0 10.0.2.15:55962 192.168.2.88:445 ESTABLISHED
tcp 1 0 10.0.2.15:56010 192.168.2.88:445 CLOSE_WAIT
tcp 0 1 10.0.2.15:56058 192.168.2.88:445 SYN_SENT
tcp 0 0 10.0.2.15:56056 192.168.2.88:445 LAST_ACK
tcp 0 0 10.0.2.15:56104 192.168.2.88:445 ESTABLISHED
tcp 0 0 10.0.2.15:56162 192.168.2.88:445 ESTABLISHED
tcp 0 0 10.0.2.15:56202 192.168.2.88:445 ESTABLISHED
tcp 0 1 10.0.2.15:56246 192.168.2.88:445 SYN_SENT
tcp 0 0 10.0.2.15:56290 192.168.2.88:445 ESTABLISHED
....etc.
Rebooting in 4.0.8 makes the issue go away, and I can have the shares mounted
as long as I want without a connection flood. Hence I assume that it's a
smbclient + Kernel 4.0.9 issue
-- System Information:
Debian Release: 8.7
APT prefers stable-updates
APT policy: (500, 'stable-updates'), (500, 'stable')
Architecture: amd64 (x86_64)
Kernel: Linux 4.9.0-0.bpo.1-amd64 (SMP w/2 CPU cores)
Locale: LANG=en_DK.UTF-8, LC_CTYPE=en_DK.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: sysvinit (via /sbin/init)
Versions of packages smbclient depends on:
ii dpkg 1.17.27
ii libarchive13 3.1.2-11+deb8u3
ii libbsd0 0.7.0-2
ii libc6 2.19-18+deb8u7
ii libpopt0 1.16-10
ii libreadline6 6.3-8+b3
ii libsmbclient 2:4.2.14+dfsg-0+deb8u2
ii libtalloc2 2.1.2-0+deb8u1
ii libtevent0 0.9.28-0+deb8u1
ii samba-common 2:4.2.14+dfsg-0+deb8u2
ii samba-libs 2:4.2.14+dfsg-0+deb8u2
smbclient recommends no packages.
Versions of packages smbclient suggests:
ii cifs-utils 2:6.4-1
pn heimdal-clients <none>
-- no debconf information
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