Date: Wed, 16 Dec 1998 02:33:50 +0100 (CET) From: Oliver Fromme <olli@dorifer.heim3.tu-clausthal.de> To: freebsd-current@FreeBSD.ORG Subject: Re: modification to exec in the kernel? Message-ID: <199812160133.CAA09939@dorifer.heim3.tu-clausthal.de>
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Joe Abley wrote in list.freebsd-current:
> On Tue, Dec 15, 1998 at 08:44:16AM +0200, Mark Murray wrote:
> > Your security model is flawed. A user can do anything she wants
> > (justabout) with shellscript and perl. Picking on compiled binaries
> > is not going to make you that much safer.
>
> "Just about" - so there are _some_ exploits that would require a user-supplied
> binary? So preventing execution of user-supplied binaries does give _some_
> safety benefit?
>
> I take your point, though - I was forgetting how much feature bloat there
> is in perl.
In fact, you can execute arbitrary byte code in perl5.
#!/usr/local/bin/perl
require DynaLoader;
DynaLoader::dl_install_xsub("main::hangme",
unpack("I", pack("P4", "\xF0\x0F\xC7\xC8")));
hangme();
In case you haven't recognized it, that beast is equivalent
with the following C "program":
unsigned char main[4] = {0xF0, 0x0F, 0xC7, 0xC8};
> Why people can't just make do with awk is a little beyond me :)
Me too. :)
Quite a lot of my scripts begin with #!/usr/bin/awk -f :)
Regards
Oliver
--
Oliver Fromme, Leibnizstr. 18/61, 38678 Clausthal, Germany
(Info: finger userinfo:olli@dorifer.heim3.tu-clausthal.de)
"In jedem Stück Kohle wartet ein Diamant auf seine Geburt"
(Terry Pratchett)
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