Bug 140069

Summary:

[GStreamer] Disable gst-plugin-scanner if seccomp filters are enabled

Product:

WebKit

Reporter:

Michael Catanzaro <mcatanzaro>

Component:

WebCore Misc.

Assignee:

Michael Catanzaro <mcatanzaro>

Status:

RESOLVED FIXED

Severity:

Normal

CC:

cgarcia, commit-queue, mcatanzaro, pnormand, slomo, tmpsantos

Priority:

Version:

528+ (Nightly build)

Hardware:

OS:

Linux

Bug Depends on:

142978

Bug Blocks:

110014

Attachments:

Description	Flags
Patch	none

Description Michael Catanzaro 2015-01-04 20:00:21 PST

If seccomp filters are enabled, any child processes we create are doomed if they try to use a trapped syscall: the child will receive SIGSYS and dump core. There appears to be no way around this.

Fortunately, the gstreamer developers had mad prescience and provided us with a way to move plugin scanning in-process, so we don't need the helper binary at all.

Comment 1 Michael Catanzaro 2015-01-04 20:05:48 PST

Created attachment 243957 [details]
Patch

Comment 2 WebKit Commit Bot 2015-01-05 01:23:09 PST

Comment on attachment 243957 [details]
Patch

Clearing flags on attachment: 243957

Committed r177896: <http://trac.webkit.org/changeset/177896>

Comment 3 WebKit Commit Bot 2015-01-05 01:23:13 PST

All reviewed patches have been landed.  Closing bug.

Comment 4 Sebastian Dröge (slomo) 2015-01-06 03:47:28 PST

Note that putting the plugin scanning in-process has two huge disadvantages though. You will dlopen() all (changed) plugins, which in turn loads all dependent libraries... and they will never be unloaded again for this process. And if any plugin crashes during initialization, it will just take your application process with it.

Disabling the plugin scanner can't be the right solution for this approach, and if there's no other way I would say that seccomp is currently broken by design.

Comment 5 Michael Catanzaro 2015-01-06 10:52:00 PST

(In reply to comment #4)
> Disabling the plugin scanner can't be the right solution for this approach,
> and if there's no other way I would say that seccomp is currently broken by
> design.

I'm glad I CCed you. Let's discuss this in bug #140131.

Comment 6 WebKit Commit Bot 2015-03-23 13:24:09 PDT

Re-opened since this is blocked by bug 142978

Comment 7 Michael Catanzaro 2015-03-23 13:25:35 PDT

Go away bug, we'll use bug #140131 for this.