Bug 676256 - SELinux is preventing /usr/bin/vlc from 'mmap_zero' accesses on the memprotect Unknown.
Summary: SELinux is preventing /usr/bin/vlc from 'mmap_zero' accesses on the memprotec...
Keywords:
Status: CLOSED CANTFIX
Alias: None
Product: Fedora
Classification: Fedora
Component: selinux-policy
Version: 14
Hardware: i386
OS: Linux
unspecified
medium
Target Milestone: ---
Assignee: Miroslav Grepl
QA Contact: Fedora Extras Quality Assurance
URL:
Whiteboard: setroubleshoot_trace_hash:2e4568138aa...
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2011-02-09 09:06 UTC by plainbox
Modified: 2011-10-31 13:09 UTC (History)
4 users (show)

Fixed In Version:
Doc Type: Bug Fix
Doc Text:
Clone Of:
Environment:
Last Closed: 2011-02-09 11:15:09 UTC
Type: ---


Attachments (Terms of Use)

Description plainbox 2011-02-09 09:06:11 UTC
SELinux is preventing /usr/bin/vlc from 'mmap_zero' accesses on the memprotect Unknown.

*****  Plugin mmap_zero (53.1 confidence) suggests  **************************

If you do not think /usr/bin/vlc should need to mmap low memory in the kernel.
Then you may be under attack by a hacker, this is a very dangerous access.
Do
contact your security administrator and report this issue.

*****  Plugin catchall_boolean (42.6 confidence) suggests  *******************

If you want to control the ability to mmap a low area of the address space, as configured by /proc/sys/kernel/mmap_min_addr.
Then you must tell SELinux about this by enabling the 'mmap_low_allowed' boolean.
Do
setsebool -P mmap_low_allowed 1

*****  Plugin catchall (5.76 confidence) suggests  ***************************

If you believe that vlc should be allowed mmap_zero access on the Unknown memprotect by default.
Then you should report this as a bug.
You can generate a local policy module to allow this access.
Do
allow this access for now by executing:
# grep vlc /var/log/audit/audit.log | audit2allow -M mypol
# semodule -i mypol.pp

Additional Information:
Source Context                unconfined_u:unconfined_r:unconfined_execmem_t:s0-
                              s0:c0.c1023
Target Context                unconfined_u:unconfined_r:unconfined_execmem_t:s0-
                              s0:c0.c1023
Target Objects                Unknown [ memprotect ]
Source                        vlc
Source Path                   /usr/bin/vlc
Port                          <Unknown>
Host                          (removed)
Source RPM Packages           vlc-core-1.1.7-1.fc14
Target RPM Packages           
Policy RPM                    selinux-policy-3.9.7-29.fc14
Selinux Enabled               True
Policy Type                   targeted
Enforcing Mode                Enforcing
Host Name                     (removed)
Platform                      Linux (removed) 2.6.35.10-74.fc14.i686 #1 SMP
                              Thu Dec 23 16:17:40 UTC 2010 i686 i686
Alert Count                   112
First Seen                    Wed 09 Feb 2011 04:39:44 PM MYT
Last Seen                     Wed 09 Feb 2011 04:39:44 PM MYT
Local ID                      a7832be7-0008-4e88-984d-381be2a240ce

Raw Audit Messages
type=AVC msg=audit(1297240784.843:261): avc:  denied  { mmap_zero } for  pid=19773 comm="vlc" scontext=unconfined_u:unconfined_r:unconfined_execmem_t:s0-s0:c0.c1023 tcontext=unconfined_u:unconfined_r:unconfined_execmem_t:s0-s0:c0.c1023 tclass=memprotect


type=SYSCALL msg=audit(1297240784.843:261): arch=i386 syscall=mmap2 success=no exit=EACCES a0=0 a1=1000 a2=3 a3=22 items=0 ppid=1 pid=19773 auid=500 uid=500 gid=500 euid=500 suid=500 fsuid=500 egid=500 sgid=500 fsgid=500 tty=(none) ses=1 comm=vlc exe=/usr/bin/vlc subj=unconfined_u:unconfined_r:unconfined_execmem_t:s0-s0:c0.c1023 key=(null)

Hash: vlc,unconfined_execmem_t,unconfined_execmem_t,memprotect,mmap_zero

audit2allow

#============= unconfined_execmem_t ==============
#!!!! This avc can be allowed using the boolean 'mmap_low_allowed'

allow unconfined_execmem_t self:memprotect mmap_zero;

audit2allow -R

#============= unconfined_execmem_t ==============
#!!!! This avc can be allowed using the boolean 'mmap_low_allowed'

allow unconfined_execmem_t self:memprotect mmap_zero;

Comment 1 Miroslav Grepl 2011-02-09 11:15:09 UTC
This is not something we will allow.  mmap_zero is very dangerous,  Please
report to vlc.


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