selinux October 2008

selinux@lists.fedoraproject.org

32 participants
46 discussions

SELinux and VLC player
by Rahul Sundaram 18 Oct '08

18 Oct '08

Hi Summary: SELinux is preventing vlc from making the program stack executable. Detailed Description: [SELinux is in permissive mode, the operation would have been denied but was permitted due to permissive mode.] The vlc application attempted to make its stack executable. This is a potential security problem. This should never ever be necessary. Stack memory is not executable on most OSes these days and this will not change. Executable stack memory is one of the biggest security problems. An execstack error might in fact be most likely raised by malicious code. Applications are sometimes coded incorrectly and request this permission. The SELinux Memory Protection Tests (http://people.redhat.com/drepper/selinux-mem.html) web page explains how to remove this requirement. If vlc does not work and you need it to work, you can configure SELinux temporarily to allow this access until the application is fixed. Please file a bug report (http://bugzilla.redhat.com/bugzilla/enter_bug.cgi) against this package. Allowing Access: Sometimes a library is accidentally marked with the execstack flag, if you find a library with this flag you can clear it with the execstack -c LIBRARY_PATH. Then retry your application. If the app continues to not work, you can turn the flag back on with execstack -s LIBRARY_PATH. Otherwise, if you trust vlc to run correctly, you can change the context of the executable to unconfined_execmem_exec_t. "chcon -t unconfined_execmem_exec_t '/usr/bin/vlc'" You must also change the default file context files on the system in order to preserve them even on a full relabel. "semanage fcontext -a -t unconfined_execmem_exec_t '/usr/bin/vlc'" Fix Command: chcon -t unconfined_execmem_exec_t '/usr/bin/vlc' Additional Information: Source Context unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1 023 Target Context unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1 023 Target Objects None [ process ] Source vlc Source Path /usr/bin/vlc Port <Unknown> Host sundaram Source RPM Packages vlc-core-0.9.4-1.fc10 Target RPM Packages Policy RPM selinux-policy-3.5.12-3.fc10 Selinux Enabled True Policy Type targeted MLS Enabled True Enforcing Mode Permissive Plugin Name allow_execstack Host Name sundaram Platform Linux sundaram 2.6.27-13.fc10.i686 #1 SMP Wed Oct 15 02:06:26 EDT 2008 i686 i686 Alert Count 1 First Seen Sat 18 Oct 2008 08:18:06 AM IST Last Seen Sat 18 Oct 2008 08:18:06 AM IST Local ID 84968ddd-4d14-4680-8692-66835b0c5e43 Line Numbers Raw Audit Messages node=sundaram type=AVC msg=audit(1224298086.835:270): avc: denied { execstack } for pid=25126 comm="vlc" scontext=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 tcontext=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 tclass=process node=sundaram type=SYSCALL msg=audit(1224298086.835:270): arch=40000003 syscall=125 success=yes exit=0 a0=bf8a4000 a1=1000 a2=1000007 a3=fffff000 items=0 ppid=1 pid=25126 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_t:s0-s0:c0.c1023 key=(null) Rahul

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Mplayer Firefox plugin - SELinux policy issue
by Rahul Sundaram 17 Oct '08

17 Oct '08

Hi, Summary: SELinux is preventing firefox from changing a writable memory segment executable. Detailed Description: [SELinux is in permissive mode, the operation would have been denied but was permitted due to permissive mode.] The firefox application attempted to change the access protection of memory (e.g., allocated using malloc). This is a potential security problem. Applications should not be doing this. Applications are sometimes coded incorrectly and request this permission. The SELinux Memory Protection Tests (http://people.redhat.com/drepper/selinux-mem.html) web page explains how to remove this requirement. If firefox does not work and you need it to work, you can configure SELinux temporarily to allow this access until the application is fixed. Please file a bug report (http://bugzilla.redhat.com/bugzilla/enter_bug.cgi) against this package. Allowing Access: If you trust firefox to run correctly, you can change the context of the executable to unconfined_execmem_exec_t. "chcon -t unconfined_execmem_exec_t '/usr/lib/firefox-3.0.2/firefox'". You must also change the default file context files on the system in order to preserve them even on a full relabel. "semanage fcontext -a -t unconfined_execmem_exec_t '/usr/lib/firefox-3.0.2/firefox'" Fix Command: chcon -t unconfined_execmem_exec_t '/usr/lib/firefox-3.0.2/firefox' Additional Information: Source Context unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1 023 Target Context unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1 023 Target Objects None [ process ] Source mplayer Source Path /usr/bin/mplayer Port <Unknown> Host sundaram Source RPM Packages firefox-3.0.2-1.fc10 Target RPM Packages Policy RPM selinux-policy-3.5.12-2.fc10 Selinux Enabled True Policy Type targeted MLS Enabled True Enforcing Mode Permissive Plugin Name allow_execmem Host Name sundaram Platform Linux sundaram2.6.27-13.fc10.i686 #1 SMP Wed Oct 15 02:06:26 EDT 2008 i686 i686 Alert Count 2203 First Seen Thu 09 Oct 2008 01:27:29 PM IST Last Seen Sat 18 Oct 2008 01:38:06 AM IST Local ID 38a635ac-3f04-4c17-a077-0fc45f309767 Line Numbers Raw Audit Messages node=type=AVC msg=audit(1224274086.429:152): avc: denied { execmem } for pid=30194 comm="firefox" scontext=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 tcontext=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 tclass=process node=sundaram type=SYSCALL msg=audit(1224274086.429:152): arch=40000003 syscall=125 success=yes exit=0 a0=b2ce4000 a1=1000 a2=5 a3=bfaf8f0c items=0 ppid=30180 pid=30194 auid=500 uid=500 gid=500 euid=500 suid=500 fsuid=500 egid=500 sgid=500 fsgid=500 tty=(none) ses=1 comm="firefox" exe="/usr/lib/firefox-3.0.2/firefox" subj=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 key=(null) --- Rahul

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Qns on SELinux policy tool on fedora 7
by lionel ong 17 Oct '08

17 Oct '08

Hi! I am Lionel and I have just suscribed to the fedora-selinux-list . I have been working on fedora 7 recently and is currently testing out the policy management tool provided by SELinux. Does anyone knows how to use the tool to create a policy such that it makes Firefox work on any other TCP port other than its default port 80? Does the "file name" the tool requires me to enter really matters? or does it just require the correct executable to be selected? Any advice would be a great help! Thanks! _________________________________________________________________ Easily publish your photos to your Spaces with Photo Gallery. http://get.live.com/photogallery/overview

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selinux denies dmesg
by Antonio Olivares 17 Oct '08

17 Oct '08

Dear fellow selinux experts, After recovering from a kernel panic to check up on the filesystem, I run dmesg and I encounter some avc's [olivares@riohigh ~]$ dmesg | grep avc type=1400 audit(1224195506.669:4): avc: denied { sys_resource } for pid=1534 comm="dmesg" capability=24 scontext=system_u:system_r:dmesg_t:s0 tcontext=system_u:system_r:dmesg_t:s0 tclass=capability type=1400 audit(1224195506.669:5): avc: denied { sys_resource } for pid=1534 comm="dmesg" capability=24 scontext=system_u:system_r:dmesg_t:s0 tcontext=system_u:system_r:dmesg_t:s0 tclass=capability type=1400 audit(1224195506.669:6): avc: denied { sys_resource } for pid=1534 comm="dmesg" capability=24 scontext=system_u:system_r:dmesg_t:s0 tcontext=system_u:system_r:dmesg_t:s0 tclass=capability type=1400 audit(1224195506.669:7): avc: denied { sys_resource } for pid=1534 comm="dmesg" capability=24 scontext=system_u:system_r:dmesg_t:s0 tcontext=system_u:system_r:dmesg_t:s0 tclass=capability type=1400 audit(1224195506.670:8): avc: denied { sys_resource } for pid=1534 comm="dmesg" capability=24 scontext=system_u:system_r:dmesg_t:s0 tcontext=system_u:system_r:dmesg_t:s0 tclass=capability type=1400 audit(1224195506.670:9): avc: denied { sys_resource } for pid=1534 comm="dmesg" capability=24 scontext=system_u:system_r:dmesg_t:s0 tcontext=system_u:system_r:dmesg_t:s0 tclass=capability type=1400 audit(1224195506.670:10): avc: denied { sys_resource } for pid=1534 comm="dmesg" capability=24 scontext=system_u:system_r:dmesg_t:s0 tcontext=system_u:system_r:dmesg_t:s0 tclass=capability type=1400 audit(1224195506.670:11): avc: denied { sys_resource } for pid=1534 comm="dmesg" capability=24 scontext=system_u:system_r:dmesg_t:s0 tcontext=system_u:system_r:dmesg_t:s0 tclass=capability type=1400 audit(1224195506.670:12): avc: denied { sys_resource } for pid=1534 comm="dmesg" capability=24 scontext=system_u:system_r:dmesg_t:s0 tcontext=system_u:system_r:dmesg_t:s0 tclass=capability type=1400 audit(1224195506.670:13): avc: denied { sys_resource } for pid=1534 comm="dmesg" capability=24 scontext=system_u:system_r:dmesg_t:s0 tcontext=system_u:system_r:dmesg_t:s0 tclass=capability I have just updated to a newer kernel 2.6.27-13 and new selinux policy updates :) [olivares@riohigh ~]$ rpm -qa selinux* selinux-policy-3.5.12-2.fc10.noarch selinux-policy-targeted-3.5.12-2.fc10.noarch [olivares@riohigh ~]$ What do I do? Thanks, Antonio

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Denied avcs
by Antonio Olivares 16 Oct '08

16 Oct '08

Dear fellow testers and selinux experts, I have encountered several avcs. I want to ask you for advice before applying the suggested fixes. Summary: SELinux is preventing knotify4 from making the program stack executable. Detailed Description: The knotify4 application attempted to make its stack executable. This is a potential security problem. This should never ever be necessary. Stack memory is not executable on most OSes these days and this will not change. Executable stack memory is one of the biggest security problems. An execstack error might in fact be most likely raised by malicious code. Applications are sometimes coded incorrectly and request this permission. The SELinux Memory Protection Tests (http://people.redhat.com/drepper/selinux-mem.html) web page explains how to remove this requirement. If knotify4 does not work and you need it to work, you can configure SELinux temporarily to allow this access until the application is fixed. Please file a bug report (http://bugzilla.redhat.com/bugzilla/enter_bug.cgi) against this package. Allowing Access: Sometimes a library is accidentally marked with the execstack flag, if you find a library with this flag you can clear it with the execstack -c LIBRARY_PATH. Then retry your application. If the app continues to not work, you can turn the flag back on with execstack -s LIBRARY_PATH. Otherwise, if you trust knotify4 to run correctly, you can change the context of the executable to unconfined_execmem_exec_t. "chcon -t unconfined_execmem_exec_t '/usr/bin/knotify4'" You must also change the default file context files on the system in order to preserve them even on a full relabel. "semanage fcontext -a -t unconfined_execmem_exec_t '/usr/bin/knotify4'" Fix Command: chcon -t unconfined_execmem_exec_t '/usr/bin/knotify4' Additional Information: Source Context unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1 023 Target Context unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1 023 Target Objects None [ process ] Source knotify4 Source Path /usr/bin/knotify4 Port <Unknown> Host riohigh Source RPM Packages kdebase-runtime-4.1.2-3.fc10 Target RPM Packages Policy RPM selinux-policy-3.5.10-3.fc10 Selinux Enabled True Policy Type targeted MLS Enabled True Enforcing Mode Enforcing Plugin Name allow_execstack Host Name riohigh Platform Linux riohigh 2.6.27-3.fc10.i686 #1 SMP Fri Oct 10 01:26:26 EDT 2008 i686 athlon Alert Count 2 First Seen Thu 16 Oct 2008 06:33:56 AM CDT Last Seen Thu 16 Oct 2008 06:33:56 AM CDT Local ID d2171be2-9d07-43e0-83bf-95f7f3e5e666 Line Numbers Raw Audit Messages node=riohigh type=AVC msg=audit(1224156836.173:93): avc: denied { execstack } for pid=2874 comm="knotify4" scontext=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 tcontext=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 tclass=process node=riohigh type=SYSCALL msg=audit(1224156836.173:93): arch=40000003 syscall=125 success=no exit=-13 a0=bf9c9000 a1=1000 a2=1000007 a3=fffff000 items=0 ppid=1 pid=2874 auid=501 uid=501 gid=501 euid=501 suid=501 fsuid=501 egid=501 sgid=501 fsgid=501 tty=(none) ses=1 comm="knotify4" exe="/usr/bin/knotify4" subj=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 key=(null) Summary: SELinux is preventing hal-acl-tool (hald_acl_t) "sys_resource" hald_acl_t. Detailed Description: SELinux denied access requested by hal-acl-tool. It is not expected that this access is required by hal-acl-tool and this access may signal an intrusion attempt. It is also possible that the specific version or configuration of the application is causing it to require additional access. Allowing Access: You can generate a local policy module to allow this access - see FAQ (http://fedora.redhat.com/docs/selinux-faq-fc5/#id2961385) Or you can disable SELinux protection altogether. Disabling SELinux protection is not recommended. Please file a bug report (http://bugzilla.redhat.com/bugzilla/enter_bug.cgi) against this package. Additional Information: Source Context system_u:system_r:hald_acl_t:s0 Target Context system_u:system_r:hald_acl_t:s0 Target Objects None [ capability ] Source hal-acl-tool Source Path /usr/libexec/hal-acl-tool Port <Unknown> Host riohigh Source RPM Packages hal-0.5.12-3.20081013git.fc10 Target RPM Packages Policy RPM selinux-policy-3.5.10-3.fc10 Selinux Enabled True Policy Type targeted MLS Enabled True Enforcing Mode Enforcing Plugin Name catchall Host Name riohigh Platform Linux riohigh 2.6.27-3.fc10.i686 #1 SMP Fri Oct 10 01:26:26 EDT 2008 i686 athlon Alert Count 73 First Seen Sat 04 Oct 2008 11:10:27 AM CDT Last Seen Thu 16 Oct 2008 06:33:03 AM CDT Local ID 16181f84-ddf2-4510-bd51-aef5ff647a63 Line Numbers Raw Audit Messages node=riohigh type=AVC msg=audit(1224156783.891:89): avc: denied { sys_resource } for pid=2568 comm="hal-acl-tool" capability=24 scontext=system_u:system_r:hald_acl_t:s0 tcontext=system_u:system_r:hald_acl_t:s0 tclass=capability node=riohigh type=SYSCALL msg=audit(1224156783.891:89): arch=40000003 syscall=4 success=yes exit=2057 a0=5 a1=b7ff4000 a2=809 a3=809 items=0 ppid=1834 pid=2568 auid=4294967295 uid=0 gid=0 euid=0 suid=0 fsuid=0 egid=0 sgid=0 fsgid=0 tty=(none) ses=4294967295 comm="hal-acl-tool" exe="/usr/libexec/hal-acl-tool" subj=system_u:system_r:hald_acl_t:s0 key=(null) Summary: SELinux is preventing console-kit-dae (consolekit_t) "sys_resource" consolekit_t. Detailed Description: SELinux denied access requested by console-kit-dae. It is not expected that this access is required by console-kit-dae and this access may signal an intrusion attempt. It is also possible that the specific version or configuration of the application is causing it to require additional access. Allowing Access: You can generate a local policy module to allow this access - see FAQ (http://fedora.redhat.com/docs/selinux-faq-fc5/#id2961385) Or you can disable SELinux protection altogether. Disabling SELinux protection is not recommended. Please file a bug report (http://bugzilla.redhat.com/bugzilla/enter_bug.cgi) against this package. Additional Information: Source Context system_u:system_r:consolekit_t:s0-s0:c0.c1023 Target Context system_u:system_r:consolekit_t:s0-s0:c0.c1023 Target Objects None [ capability ] Source console-kit-dae Source Path /usr/sbin/console-kit-daemon Port <Unknown> Host riohigh Source RPM Packages ConsoleKit-0.3.0-2.fc10 Target RPM Packages Policy RPM selinux-policy-3.5.10-3.fc10 Selinux Enabled True Policy Type targeted MLS Enabled True Enforcing Mode Enforcing Plugin Name catchall Host Name riohigh Platform Linux riohigh 2.6.27-3.fc10.i686 #1 SMP Fri Oct 10 01:26:26 EDT 2008 i686 athlon Alert Count 87 First Seen Fri 03 Oct 2008 06:14:33 PM CDT Last Seen Thu 16 Oct 2008 06:33:02 AM CDT Local ID 0c8f36ea-d6b2-4646-ba59-1cdf5e6a0ee0 Line Numbers Raw Audit Messages node=riohigh type=AVC msg=audit(1224156782.948:86): avc: denied { sys_resource } for pid=1770 comm="console-kit-dae" capability=24 scontext=system_u:system_r:consolekit_t:s0-s0:c0.c1023 tcontext=system_u:system_r:consolekit_t:s0-s0:c0.c1023 tclass=capability node=riohigh type=SYSCALL msg=audit(1224156782.948:86): arch=40000003 syscall=4 success=yes exit=674 a0=1a a1=8c4b790 a2=2a2 a3=8c4b790 items=0 ppid=1 pid=1770 auid=4294967295 uid=0 gid=0 euid=0 suid=0 fsuid=0 egid=0 sgid=0 fsgid=0 tty=(none) ses=4294967295 comm="console-kit-dae" exe="/usr/sbin/console-kit-daemon" subj=system_u:system_r:consolekit_t:s0-s0:c0.c1023 key=(null) I had not encountered these ones before. And before applying the fixes, I will ask if no one has encountered these ones before. TIA, Antonio

2 1

writable memory segment: mplayer
by Rahul Sundaram 15 Oct '08

15 Oct '08

Hi Since Fedora doesn't include this software, should a exception be added to the SELinux policy? "If you trust mplayer to run correctly, you can change the context of the executable to unconfined_execmem_exec_t. "chcon -t unconfined_execmem_exec_t '/usr/bin/mplayer'". You must also change the default file context files on the system in order to preserve them even on a full relabel. "semanage fcontext -a -t unconfined_execmem_exec_t '/usr/bin/mplayer'" Rahul

4 5

SELinux is preventing nm-system-setti (NetworkManager_t)
by hicham 15 Oct '08

15 Oct '08

Hello Everytime, I log on on fedora 8, I get the setroubleshoot browser popup with this: "Summary : SELinux is preventing nm-system-setti (NetworkManager_t) "read" to ./PolicyKit (hald_var_lib_t). Detailed Description : SELinux denied access requested by nm-system-setti. It is not expected that this access is required by nm-system-setti and this access may signal an intrusion attempt. It is also possible that the specific version or configuration of the application is causing it to require additional access. Allowing Access Sometimes labeling problems can cause SELinux denials. You could try to restore the default system file context for ./PolicyKit, restorecon -v './PolicyKit' If this does not work, there is currently no automatic way to allow this access. Instead, you can generate a local policy module to allow this access - see FAQ Or you can disable SELinux protection altogether. Disabling SELinux protection is not recommended. Please file a bug report against this package. " "this access may signal an intrusion attempt", is someone is trying to get into my computer ? how do I fix that ? thanks

2 1

running star archive through restorecon
by Murray McAllister 15 Oct '08

15 Oct '08

Hi, This is probably user error, sorry :) 1. touch file{1,2}; ls -Z -rw-rw-r-- murray murray unconfined_u:object_r:user_home_t:s0 file1 -rw-rw-r-- murray murray unconfined_u:object_r:user_home_t:s0 file2 2. chcon -l s0:c2 file{1,2}; ls -Z -rw-rw-r-- murray murray unconfined_u:object_r:user_home_t:s0:c2 file1 -rw-rw-r-- murray murray unconfined_u:object_r:user_home_t:s0:c2 file2 2. star -xattr -H exustar -c -f test.star file{1,2} star: 1 blocks + 0 bytes (total of 10240 bytes = 10.00k). 3. cd /var/www/html/ 4. sudo star -x -f test.star | restorecon -f - 5. ls -Z -rw-rw-r-- murray murray unconfined_u:object_r:user_home_t:s0:c2 file1 -rw-rw-r-- murray murray unconfined_u:object_r:user_home_t:s0:c2 file2 -rw-r--r-- root root unconfined_u:object_r:httpd_sys_content_t:s0 test.star file1 and file2 are still s0:c2. When I perform the same steps with tar (using tar --selinux), in step 5, file1 and file2 use s0. Does anyone have any pointers as to where I've gone wrong? I don't get any denials when running "sudo star -x -f test.star | restorecon -f -". I am using: Fedora release 9.92 (Rawhide) star-1.5a84-6.fc10.i386 tar-1.20-3.fc10.i386 policycoreutils-2.0.57-1.fc10.i386 selinux-policy-targeted-3.5.10-3.fc10.noarch selinux-policy-3.5.10-3.fc10.noarch Cheers :)

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Selinux config to get gutenprint 5.2 beta working under Fedora 8
by Edward Kuns 15 Oct '08

15 Oct '08

I just bought a printer that only works well via the gutenprint 5.2 beta 4 from openprinting.org. The selinux configuration to allow gutenprint to function is: /opt/gutenprint/ppds/.* -- system_u:object_r:cupsd_rw_etc_t:s0 /opt/gutenprint/s?bin/.* -- system_u:object_r:lpr_exec_t:s0 /opt/gutenprint/cups/lib/filter/.* -- system_u:object_r:bin_t:s0 I have verified that this configuration works. I haven't verified that it's the minimal configuration, but it's based on existing printer configurations from selinux. Eddie

2 1

Yet another role question
by Joe Nall 15 Oct '08

15 Oct '08

It appears that per role template expansion is disabled in the modules shipped with fedora selinux-policy 3.5.10 but enabled for modules compiled with the resulting policy (which uses a different Makefile). Why is there a difference? joe from the policy Makefile: # perrole-expansion modulename,outputfile define perrole-expansion echo "No longer doing perrole-expansion" # $(verbose) echo "ifdef(\`""$1""_per_role_template',\`" > $2 # $(call parse-rolemap,$1,$2) # $(verbose) echo "')" >> $2 # $(verbose) echo "ifdef(\`""$1""_per_userdomain_template',\`" >> $2 # $(verbose) echo "errprint(\`Warning: per_userdomain_templates have been renamed to per_role_templates (""$1""_per_userdomain_template)'__endline__)" >> $2 # $(call parse-rolemap-compat,$1,$2) # $(verbose) echo "')" >> $2 endef from /usr/share/selinux/devel/include/Makefile: # peruser-expansion modulename,outputfile define peruser-expansion $(verbose) echo "ifdef(\`""$1""_per_role_template',\`" > $2 $(call parse-rolemap,$1,$2) $(verbose) echo "')" >> $2 $(verbose) echo "ifdef(\`""$1""_per_userdomain_template',\`" >> $2 $(verbose) echo "errprint(\`Warning: per_userdomain_templates have been renamed to per_role_templates (""$1""_per_userdomain_template)'__endline__)" >> $2 $(call parse-rolemap-compat,$1,$2) $(verbose) echo "')" >> $2 endef

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selinux October 2008