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Bug 1312097 - selinux: semanage dontaudit off and vsftpd together causes crash
Summary: selinux: semanage dontaudit off and vsftpd together causes crash
Keywords:
Status: CLOSED NOTABUG
Alias: None
Product: Red Hat Enterprise Linux 7
Classification: Red Hat
Component: selinux-policy
Version: 7.2
Hardware: x86_64
OS: Linux
low
medium
Target Milestone: rc
: ---
Assignee: Lukas Vrabec
QA Contact: BaseOS QE Security Team
URL:
Whiteboard:
Depends On:
Blocks: 1393066
TreeView+ depends on / blocked
 
Reported: 2016-02-25 17:51 UTC by mheadlee
Modified: 2023-09-14 03:18 UTC (History)
7 users (show)

Fixed In Version:
Doc Type: If docs needed, set a value
Doc Text:
Clone Of:
Environment:
Last Closed: 2017-08-17 07:59:16 UTC
Target Upstream Version:
Embargoed:

Attachments (Terms of Use)
audit.log from system experiencing the above described issue. (217.46 KB, text/plain)
2016-03-17 12:19 UTC, mheadlee 		no flags Details
Screenshot of machine before starting vsftpd. (17.24 KB, image/png)
2016-03-17 12:27 UTC, mheadlee 		no flags Details
Screenshot of machine after starting vsftpd. (15.58 KB, image/png)
2016-03-17 12:28 UTC, mheadlee 		no flags Details
View All

Description mheadlee 2016-02-25 17:51:02 UTC 
Description of problem:

    * vsftpd generates boat loads (technical figure) of SELinux denials which are ignored by dontaudit rules.
    * Disabling dontaudit rules causes boat loads of denials to be logged to audit.log.
    * setroubleshoot is run from dbus for each SELinux denial.
    * Thousands of setroubleshoots start simultaneously.
    * Machine runs out of memory and locks
    * Reboot does not fix problem, machine needs to be booted into rescue and audit.log truncated to fix

How reproducible:
Always

Steps to Reproduce:
1. # yum -y install vsftpd
2. # semanage dontaudit off
3. # systemctl start vsftpd


Actual results:
System runs out of memory and crashes. 

Expected results:
System doesn't crash.
Comment 4 Miroslav Grepl 2016-03-17 09:46:05 UTC 
(In reply to mheadlee from comment #0)
> Description of problem:
> 
>     * vsftpd generates boat loads (technical figure) of SELinux denials
> which are ignored by dontaudit rules.
>     * Disabling dontaudit rules causes boat loads of denials to be logged to
> audit.log.
>     * setroubleshoot is run from dbus for each SELinux denial.
>     * Thousands of setroubleshoots start simultaneously.
>     * Machine runs out of memory and locks
>     * Reboot does not fix problem, machine needs to be booted into rescue
> and audit.log truncated to fix
> 
> How reproducible:
> Always
> 
> Steps to Reproduce:
> 1. # yum -y install vsftpd
> 2. # semanage dontaudit off
> 3. # systemctl start vsftpd
> 
> 
> Actual results:
> System runs out of memory and crashes. 
> 
> Expected results:
> System doesn't crash.

Could you attach examples of these AVCs?
Comment 5 mheadlee 2016-03-17 12:19:29 UTC 
Created attachment 1137372 [details]
audit.log from system experiencing the above described issue.

Specifically note "1458216459.180:125" on line 579 when vsftpd is started. System ran out of memory and crashed on line 924.
Comment 6 mheadlee 2016-03-17 12:27:37 UTC 
Created attachment 1137378 [details]
Screenshot of machine before starting vsftpd.
Comment 7 mheadlee 2016-03-17 12:28:07 UTC 
Created attachment 1137380 [details]
Screenshot of machine after starting vsftpd.
Comment 8 Miroslav Grepl 2016-03-17 13:04:31 UTC 
Ok so there is no problem with vsftpd in enforcing mode if you have turned dontaudit rules on, right?
Comment 9 Milos Malik 2016-03-17 13:31:38 UTC 
Based on the last screenshot, the machine swaps heavily (load over 7, kswapd0 process is shown as first in the top output). How much memory does the machine have? Maybe setroubleshoot-server (written python) is consuming too much memory.
Comment 12 Lukas Vrabec 2017-08-17 07:59:16 UTC 
Related to comment#9, it looks like the issue is with the HW capacity, not issue in selinux-policy. Closing this BZ as NOTABUG.
Comment 13 Red Hat Bugzilla 2023-09-14 03:18:33 UTC 
The needinfo request[s] on this closed bug have been removed as they have been unresolved for 1000 days
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