Question RE: Linux Mode

Richards, Toby toby.richards at
Tue Jun 29 03:35:12 UTC 2010

So as far as I can tell, turning Linux Mode on exposes another threat vector. Can I turn on Linux Mode ONLY for a single binary (the Flash plugin)?

-----Original Message-----
From: Polytropon [mailto:freebsd at]
Sent: Mon 28-Jun-10 2:41 PM
To: Richards, Toby
Cc: freebsd-questions at
Subject: Re: Question RE: Linux Mode
On Mon, 28 Jun 2010 13:57:33 -0700, "Richards, Toby" <toby.richards at> wrote:
> My question is this: If I turn on Linux mode, don't I sacrifice the
> security, performance, and other benefits of the FreeBSD kernel vice
> Linux?

No. FreeBSD's "Linux mode" is nothing more or less than an ABI - an
alternative binary interface. Linux programs "communicate" through
this interface instead of FreeBSD's default one.

Of course, there *are* security implications, as on Linux. Security
limits are given by the FreeBSD infrastructure (e. g. "Flash" based
malware trying to access system files -> no; defective "Flash"
implementation causing a memory leak -> possible).

I don't use "Flash" anymore so I can't be more specific. Last time
I tried it worked nearly flawlessly with Firefox.

A personal note: Sometimes, I found that Linux programs ran faster
on FreeBSD Linux ABI than on native Linux, but as I'm not a regular
Linux user, my opinion isn't worth more than 2 cent. :-)

Magdeburg, Germany
Happy FreeBSD user since 4.0
Andra moi ennepe, Mousa, ...

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