Summary: SELinux is preventing /usr/libexec/gstreamer-0.10/gst-plugin-scanner from making the program stack executable. Detailed Description: The gst-plugin-scan 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://www.akkadia.org/drepper/selinux-mem.html) web page explains how to remove this requirement. If gst-plugin-scan 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. 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 gst-plugin-scan to run correctly, you can change the context of the executable to execmem_exec_t. "chcon -t execmem_exec_t '/usr/libexec/gstreamer-0.10/gst-plugin-scanner'" 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 execmem_exec_t '/usr/libexec/gstreamer-0.10/gst-plugin-scanner'" Fix Command: chcon -t execmem_exec_t '/usr/libexec/gstreamer-0.10/gst-plugin-scanner' 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 gst-plugin-scan Source Path /usr/libexec/gstreamer-0.10/gst-plugin-scanner Port <Unknown> Host (removed) Source RPM Packages gstreamer-0.10.30-1.fc14 Target RPM Packages Policy RPM selinux-policy-3.9.5-10.fc14 Selinux Enabled True Policy Type targeted Enforcing Mode Enforcing Plugin Name allow_execstack Host Name (removed) Platform Linux (removed) 2.6.35.6-39.fc14.x86_64 #1 SMP Fri Oct 8 16:23:12 UTC 2010 x86_64 x86_64 Alert Count 1 First Seen Wed 13 Oct 2010 04:36:12 PM CEST Last Seen Wed 13 Oct 2010 04:36:12 PM CEST Local ID 954cf1c0-b070-4cfa-ba2d-63af1c17853f Line Numbers Raw Audit Messages node=(removed) type=AVC msg=audit(1286980572.20:115): avc: denied { execstack } for pid=5291 comm="gst-plugin-scan" 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=(removed) type=SYSCALL msg=audit(1286980572.20:115): arch=c000003e syscall=10 success=no exit=-13 a0=7fff2c917000 a1=1000 a2=1000007 a3=7fb9bffe9000 items=0 ppid=5129 pid=5291 auid=501 uid=501 gid=100 euid=501 suid=501 fsuid=501 egid=100 sgid=100 fsgid=100 tty=(none) ses=1 comm="gst-plugin-scan" exe="/usr/libexec/gstreamer-0.10/gst-plugin-scanner" subj=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 key=(null) Hash String generated from allow_execstack,gst-plugin-scan,unconfined_t,unconfined_t,process,execstack audit2allow suggests: #============= unconfined_t ============== #!!!! This avc can be allowed using the boolean 'allow_execstack' allow unconfined_t self:process execstack;
I don't think gstreamer should require execstack.
Considering that gst-plugin-scanner just initializes all GStreamer plugins to scan them, this sounds like a lot of places where this can be caused. Is there a way to get a stack trace for SELinux audit failures?
First take a look at the shared library and see if it has the execstack flag turned on . execstack -q
I can tell you that neither the GStreamer libraries nor any of the GStreamer plugins require execstack. That doesn't mean however that there might be plugins (that load other plugins) that link to libraries that are broken. Which is why I'm asking. So unless there's a way to figure out what's causing the problem, I'm gonna close this as INSUFFICIENT_DATA.
On my system (Linux 2.6.35.10-74.fc14.i686) the libraries with the execstack flag are /usr/lib/libxvidcore.so.4 and /usr/lib/libxvidcore.so.4.2 (from xvidcore-1.2.2-1.fc14.i686) and these are used by libgstffmpeg.so and libgstpostproc.so from gstreamer-ffmpeg-0.10.11-1.fc14.i686 and libgstxvid.so from gstreamer-plugins-bad-0.10.20-2.fc14.i686.
If you turn the flag off, does everything work?
Hard to say if 'everything' works, but if I leave the execstack flag active, totem won't play an XVID file at all : If I remove ~/.gstreamer-0.10 and the run gst-inspect , this refuses to add the xvid library (because of the exestack flag). and Totem reports it doesn't have a plugin to handle the xvid file. If I remove the flag, and re-run gst-inspect, the xvid library is added, and totem does play the same xvid file. I used the file http://samples.mplayerhq.hu/V-codecs/XVID/ttm1.avi to test (cause I don't have any XVID samples) and the quality is horrible. Don't know if it is the sample or somethings else.
Ok this means the flag is not necessary, I believe. Not sure why the quality would stink, but I am pretty sure this is not caused by SELinux. *** This bug has been marked as a duplicate of bug 652297 ***