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A subsystem to restrict programs into a “reduced feature operating model”

marc.info

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Re: A subsystem to restrict programs into a “reduced feature operating model”

#71
post #58

Earlier quoted context omitted.

Sounds like you're doing something unnecessarily more complicated than this: $ time cvs -d anoncvs@anoncvs1.ca.openbsd.org:/cvs export -rHEAD src/sys/kern/kern_fork.c U src/sys/kern/kern_fork.c 0m2.73s real 0m0.06s user 0m0.04s system

Yep, I was grabbing `src` instead of `src/sys/kern/kern_fork.c`. I've completely forgotten how to CVS, and I'm okay with that.

What are the reasons why CVS is still in use?

Re: A subsystem to restrict programs into a “reduced feature operating model”

#72

Windows 8 has an equivalent of this, using a "mitigation policy" called ProcessSystemCallDisablePolicy, which is set using SetProcessMitigationPolicy(). Chrome uses this for their sandbox of rendering processes.

It looks like you can only disable GUI calls with it (the very sparse documentation seems to contradict itself a bit though). Also, a model in which you specify which calls you want to enable (and everything else gets disabled) is stronger than one in which you specify which ones you want to disable.

Re: A subsystem to restrict programs into a “reduced feature operating model”

#74
post #64

Earlier quoted context omitted.

Whats the name of this app? Can it run without root permissions?

xprivacy/xposed framework, no

I wish Android allowed power users to create "root accounts" on Android, similar to how you can create Admin accounts on Windows, but be completely isolated from the default safe account.

Re: A subsystem to restrict programs into a “reduced feature operating model”

#75
post #72

Windows 8 has an equivalent of this, using a "mitigation policy" called ProcessSystemCallDisablePolicy, which is set using SetProcessMitigationPolicy(). Chrome uses this for their sandbox of rendering processes.

It looks like you can only disable GUI calls with it (the very sparse documentation seems to contradict itself a bit though). Also, a model in which you specify which calls you want to enable (and everything else gets disabled) is stronger than one in which you specify which ones you want to disable.

Indeed, it's the whole whitelist vs blacklist [1] debate. Whitelists are radically safer.

[1] - https://farm9.staticflickr.com/8669/16418068728_b8dd8aa200_c...

Re: A subsystem to restrict programs into a “reduced feature operating model”

#76

This won't work for programs that allow for plugins, which are arguably those that need the most protection. Programs don't generally know what permissions plugins when they are compiled.

the flags will need to be configurable through config file (e.g nginx, apache). When you explicitly grant more access because of a plugin, you know what you are getting into.

But assume nginx supports tame now, you know at least what the process can do and what it cannot do explicitly. If one day a zero-day attack was discovered in nginx, nginx running tame will have a lesser security impact, at least in theory.

Re: A subsystem to restrict programs into a “reduced feature operating model”

#77

Earlier quoted context omitted.

I'm `cvs get`ting as fast as I can to read the rest of sys_fork.c to sate my curiosity, but CVS incredibly slow. I'm spoiled by how git packs the repo.

turned out to be way faster just to grab http://mirrors.sonic.net/pub/OpenBSD/5.7/sys.tar.gz , if anybody else wants to poke around and doesn't want to wait for cvs.

You can also view the source on the cvs web mirror: http://cvsweb.openbsd.org/cgi-bin/cvsweb/src/

Re: A subsystem to restrict programs into a “reduced feature operating model”

#78
post #22

This doesn't seem particularly better than Linux's seccomp-bpf or OS X's seatbelt. In particular, I don't really understand the complaint about not wanting to write a program, then turning around and writing a system call , running with full privilege on the system, that hardcodes all sorts of things about userspace. I wish he'd acknowledge and discuss prior, effective work in this space instead of saying things "sho…

You might well be able to implement tame() entirely in userspace using seccomp-bpf.

Re: A subsystem to restrict programs into a “reduced feature operating model”

#79
post #78
post #22

This doesn't seem particularly better than Linux's seccomp-bpf or OS X's seatbelt. In particular, I don't really understand the complaint about not wanting to write a program, then turning around and writing a system call , running with full privilege on the system, that hardcodes all sorts of things about userspace. I wish he'd acknowledge and discuss prior, effective work in this space instead of saying things "sho…

You might well be able to implement tame() entirely in userspace using seccomp-bpf.

And that wouldn't be a bad thing; seccomp could do with a simpler user interface (in addition to the current, more powerfull one).

Re: A subsystem to restrict programs into a “reduced feature operating model”

#80
post #71

Earlier quoted context omitted.

Yep, I was grabbing `src` instead of `src/sys/kern/kern_fork.c`. I've completely forgotten how to CVS, and I'm okay with that.

What are the reasons why CVS is still in use?

  1. it works
  2. they're used to it
  3. there isn't enough reason to change
  4. lots of infrastructure would need rebuilt if they changed
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