892996 – qemu-ga leaks fds to exec()ed processes [TestOnly]

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Bug 892996 - qemu-ga leaks fds to exec()ed processes [TestOnly]

Summary: qemu-ga leaks fds to exec()ed processes [TestOnly]

Keywords:
Status:	CLOSED ERRATA
Alias:	None
Product:	Red Hat Enterprise Linux 6
Classification:	Red Hat
Component:	qemu-kvm
Sub Component:
Version:	6.4
Hardware:	Unspecified
OS:	Unspecified
Priority:	unspecified
Severity:	unspecified
Target Milestone:	rc
Target Release:	---
Assignee:	Laszlo Ersek
QA Contact:	Virtualization Bugs
Docs Contact:
URL:
Whiteboard:
Depends On:	952873
Blocks:
TreeView+	depends on / blocked

Reported:	2013-01-08 12:26 UTC by Luiz Capitulino
Modified:	2013-11-21 06:28 UTC (History)
CC List:	10 users (show)
Fixed In Version:	qemu-kvm-0.12.1.2-2.366.el6
Doc Type:	Bug Fix
Doc Text:
Clone Of:
Environment:
Last Closed:	2013-11-21 06:28:01 UTC
Target Upstream Version:
Embargoed:

Attachments	(Terms of Use)

Links
System	ID	Private	Priority	Status	Summary	Last Updated
Red Hat Product Errata	RHSA-2013:1553	0	normal	SHIPPED_LIVE	Important: qemu-kvm security, bug fix, and enhancement update	2013-11-20 21:40:29 UTC

Description Luiz Capitulino 2013-01-08 12:26:25 UTC

Description of problem:

qemu-ga doesn't open the pid file with the O_CLOEXEC flag set, which causes it to be leaked when executing new processes.

As far as I could check, this only happens with the pid file but it's worth it to double check all opened files.


Version-Release number of selected component (if applicable): qemu-kvm-0.12.1.2-2.348.el6

How reproducible:

To reproduce the problem I've replaced /sbin/shutdown by a script that writes its pid to a file in tmp, then I executed the guest-shutdown command and checked the /proc/<pid>/fd entry:

lrwx------. 1 root root 64 Jan  8 10:08 0 -> /dev/null
lrwx------. 1 root root 64 Jan  8 10:08 1 -> /dev/null
lrwx------. 1 root root 64 Jan  8 10:08 2 -> /dev/null
lr-x------. 1 root root 64 Jan  8 10:08 255 -> /sbin/shutdown
l-wx------. 1 root root 64 Jan  8 10:08 3 -> /usr/local/var/run/qemu-ga.pid

Comment 1 Luiz Capitulino 2013-01-08 12:28:38 UTC

It seems that the log file fd is also leaked.

Comment 2 Luiz Capitulino 2013-01-09 01:41:18 UTC

Patches posted upstream:

http://lists.gnu.org/archive/html/qemu-devel/2013-01/msg01190.html

Comment 3 Laszlo Ersek 2013-04-16 22:32:04 UTC

This bug should be solved by pre-requisite bug 952873, setting TestOnly in Keywords and Summary.

Comment 7 Sibiao Luo 2013-05-09 03:14:25 UTC

Reproduce this issue on qemu-kvm-0.12.1.2-2.365.el6.x86_64.

host info:
kernel-2.6.32-376.el6.x86_64
qemu-kvm-0.12.1.2-2.365.el6.x86_64
guest info:
kernel-2.6.32-376.el6.x86_64
qemu-guest-agent-0.12.1.2-2.365.el6.x86_64

Steps:
1.start guest with virtio serial.
# /usr/libexec/qemu-kvm -M rhel6.4.0 ... -chardev socket,path=/tmp/qga.sock,server,nowait,id=qga0 -device virtio-serial -device virtserialport,chardev=qga0,name=org.qemu.guest_agent.0
2.move /sbin/shutdown to /sbin/shutdown.old.
3.create a /sbin/shutdown script containing:
  #!/bin/bash
  echo $$ > /tmp/my-pid
  sleep 1h
4.start guest agent inside guest and connect the chardev socket in host side for sending commands to guest:
# nc -U /tmp/qga.sock readline
5.issue guest-shutdown to qemu-ga.
{"execute":"guest-shutdown","arguments":{"mode":"powerdown"}}
6.get the shutdown process pid from /tmp/my-pid.
# cat /tmp/my-pid
6002
7.check the /proc/<pid>/fd dir, it shouldn't contain qemu-ga.pid
# ls -l /proc/6002/fd
total 0
lrwx------. 1 root root 64 May  8 06:53 0 -> /dev/null
lrwx------. 1 root root 64 May  8 06:53 1 -> /dev/null
lrwx------. 1 root root 64 May  8 06:53 2 -> /dev/null
lr-x------. 1 root root 64 May  8 06:53 255 -> /sbin/shutdown

Resutls:
after step 7, the log file fd was also leaked.

Make qa_ack+.

Comment 8 Sibiao Luo 2013-05-09 03:24:51 UTC

Tried the qemu-kvm-0.12.1.2-2.366.el6.x86_64, but check the /proc/<pid>/fd dir that did not contain qemu-ga.pid.

Host info:
kernel-2.6.32-376.el6.x86_64
qemu-kvm-0.12.1.2-2.366.el6.x86_64
Guest info:
kernel-2.6.32-376.el6.x86_64
qemu-guest-agent-0.12.1.2-2.366.el6.x86_64

Steps:
the same to comment #7.

Results:
check the /proc/<pid>/fd dir, but it did not contain qemu-ga.pid, the log file fd was also leaked. I tested many times for this qemu version, all of them failed.

# nc -U /tmp/qga.sock readline
{"execute":"guest-ping"}
{"return": {}}
{"execute":"guest-shutdown","arguments":{"mode":"powerdown"}}

# cat /tmp/my-pid
6070
# ls -l /proc/6070/fd
total 0
lrwx------. 1 root root 64 May  8 06:58 0 -> /dev/null
lrwx------. 1 root root 64 May  8 06:58 1 -> /dev/null
lrwx------. 1 root root 64 May  8 06:58 2 -> /dev/null
lr-x------. 1 root root 64 May  8 06:58 255 -> /sbin/shutdown

Luiz Capitulino, could you help check it, does it not fix correctly or miss the code in the patch? Should we need to RE-ASSIGNED it ?

Best Regards.
sluo

Comment 9 Sibiao Luo 2013-05-09 03:45:54 UTC

(In reply to comment #8)
> Luiz Capitulino, could you help check it, does it not fix correctly or miss
> the code in the patch? Should we need to RE-ASSIGNED it ?
> 
Ignore this conclusion please. it's right that the /proc/<pid>/fd did not contain qemu-ga.pid.
>7.check the /proc/<pid>/fd dir, it shouldn't contain qemu-ga.pid

BTW, why i cann't reproduce it ?
I also tried the qemu-kvm-0.12.1.2-2.360.el6.x86_64 and qemu-guest-agent-0.12.1.2-2.360.el6.x86_64, it also did not contail the qemu-ga.pid.

Host info:
kernel-2.6.32-376.el6.x86_64
qemu-kvm-0.12.1.2-2.360.el6.x86_64
guest info:
kernel-2.6.32-376.el6.x86_64
qemu-guest-agent-0.12.1.2-2.360.el6.x86_64

# cat /tmp/my-pid
6043
# ls -l /proc/6043/fd
total 0
lrwx------. 1 root root 64 May  8 07:39 0 -> /dev/null
lrwx------. 1 root root 64 May  8 07:39 1 -> /dev/null
lrwx------. 1 root root 64 May  8 07:39 2 -> /dev/null
lr-x------. 1 root root 64 May  8 07:39 255 -> /sbin/shutdown

Comment 10 Sibiao Luo 2013-05-09 07:05:01 UTC

I also tried qemu-kvm-0.12.1.2-2.348.el6, it is the same, it also did not contail the qemu-ga.pid.
# cat /tmp/my-pid
6057
# ls -l /proc/6057/fd
total 0
lrwx------. 1 root root 64 May  8 10:48 0 -> /dev/null
lrwx------. 1 root root 64 May  8 10:48 1 -> /dev/null
lrwx------. 1 root root 64 May  8 10:48 2 -> /dev/null
lr-x------. 1 root root 64 May  8 10:48 255 -> /sbin/shutdown

If i use the upstream qemu(QEMU 1.4.50) and just use the official guest agent(qemu-guest-agent-0.12.1.2-2.348.el6.x86_64), it is the same, it also did not contail the qemu-ga.pid. 
# cat /tmp/my-pid
5988
# ls -l /proc/5988/fd
total 0
lrwx------. 1 root root 64 May  8 11:00 0 -> /dev/null
lrwx------. 1 root root 64 May  8 11:00 1 -> /dev/null
lrwx------. 1 root root 64 May  8 11:00 2 -> /dev/null
lr-x------. 1 root root 64 May  8 11:00 255 -> /sbin/shutdown

Comment 11 Laszlo Ersek 2013-05-09 08:52:02 UTC

Hello Sibiao,

did you start qemu-ga in daemon mode (with the "service" command for example, or with the --daemonize command line option)? It only creates a pid file if you start it in daemon mode.

Also, please don't use the -363, -364, -365 builds for testing. Compare -362 against -366. Thanks!

Comment 12 Sibiao Luo 2013-05-09 09:52:35 UTC

(In reply to comment #11)
> Hello Sibiao,
> 
> did you start qemu-ga in daemon mode (with the "service" command for
> example, or with the --daemonize command line option)? It only creates a pid
> file if you start it in daemon mode.
> 
> Also, please don't use the -363, -364, -365 builds for testing. Compare -362
> against -366. Thanks!

Thanks for your kindly helps. hmm...I just started the qemu-ga service in guest(qemu-ga on) during my past testing. I re-tested it as your indication that start qemu-ga in daemon mode(qemu-ga on --daemonize) with the same steps as comment #7, the testing results as following.

- Reproduce:
host info:
kernel-2.6.32-376.el6.x86_64
qemu-kvm-0.12.1.2-2.362.el6.x86_64
guest info:
kernel-2.6.32-376.el6.x86_64
qemu-guest-agent-0.12.1.2-2.362.el6.x86_64

guest]# qemu-ga on --daemonize
guest]# ps axu | grep qemu-ga
root      6171  0.0  0.0   7144   632 ?        Ss   13:36   0:00 qemu-ga on --daemonize
root      6173  0.0  0.0 103236   872 pts/1    S+   13:36   0:00 grep qemu-ga
guest]# service qemu-ga status
qemu-ga (pid  6171) is running...

host]# nc -U /tmp/qga.sock readline
{"execute":"guest-ping"}
{"return": {}}
{"execute":"guest-shutdown","arguments":{"mode":"powerdown"}}

guest]# cat /tmp/my-pid
6186
guest]# ls -l /proc/6186/fd
total 0
lrwx------. 1 root root 64 May  8 13:37 0 -> /dev/null
lrwx------. 1 root root 64 May  8 13:37 1 -> /dev/null
lrwx------. 1 root root 64 May  8 13:37 2 -> /dev/null
lr-x------. 1 root root 64 May  8 13:37 255 -> /sbin/shutdown
l-wx------. 1 root root 64 May  8 13:37 3 -> /var/run/qemu-ga.pid

- Verification:
host info:
kernel-2.6.32-376.el6.x86_64
qemu-kvm-0.12.1.2-2.366.el6.x86_64
guest info:
kernel-2.6.32-376.el6.x86_64
qemu-guest-agent-0.12.1.2-2.366.el6.x86_64

guest]# ps axu | grep qemu-ga
root      6012  0.0  0.0 103236   872 pts/1    S+   13:41   0:00 grep qemu-ga
guest]# qemu-ga on --daemonize
guest]# ps axu | grep qemu-ga
root      6014  0.0  0.0   7180   884 ?        Ss   13:41   0:00 qemu-ga on --daemonize
root      6016  0.0  0.0 103236   864 pts/1    R+   13:41   0:00 grep qemu-ga
guest]# service qemu-ga status
qemu-ga (pid  6014) is running...

host]# nc -U /tmp/qga.sock readline
{"execute":"guest-ping"}
{"return": {}}
{"execute":"guest-shutdown","arguments":{"mode":"powerdown"}}

guest]# cat /tmp/my-pid
6035
guest]# ls -l /proc/6035/fd
total 0
lrwx------. 1 root root 64 May  8 13:43 0 -> /dev/null
lrwx------. 1 root root 64 May  8 13:43 1 -> /dev/null
lrwx------. 1 root root 64 May  8 13:43 2 -> /dev/null
lr-x------. 1 root root 64 May  8 13:43 255 -> /sbin/shutdown

Base on above, this issue has been fixed correctly.

Comment 18 Qunfang Zhang 2013-10-12 03:52:41 UTC

Setting to VERIFIED according to comment 12.

Comment 19 errata-xmlrpc 2013-11-21 06:28:01 UTC

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

http://rhn.redhat.com/errata/RHSA-2013-1553.html

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