Date: Fri, 18 Apr 2008 22:47:38 +0200 From: Jeremie Le Hen <jeremie@le-hen.org> To: Max Laier <max@love2party.net> Cc: freebsd-arch@freebsd.org Subject: Re: Integration of ProPolice in FreeBSD Message-ID: <20080418204738.GE4840@obiwan.tataz.chchile.org> In-Reply-To: <200804181945.59189.max@love2party.net> References: <20080418132749.GB4840@obiwan.tataz.chchile.org> <200804181945.59189.max@love2party.net>
next in thread | previous in thread | raw e-mail | index | archive | help
On Fri, Apr 18, 2008 at 07:45:58PM +0200, Max Laier wrote: > > First, should we build world and/or kernel with SSP by default? I've > > scamped a trivial benchmark back in 2006: timing buildworld with and > > without SSP. You can found the result on my webpage: > > http://tataz.chchile.org/~tataz/FreeSBD/SSP/#section1 > > 404 :-\ Oops, sorry I made a typo. http://tataz.chchile.org/~tataz/FreeBSD/SSP/#section1 > So I'd suggest something along the lines of: > > 1) Add the needed support symbols to libc (they don't hurt anyone, right?) Actually, they are already in libc :-). See src/sys/lib/libc/sys/stack_protector.c . > 2) Add support to build kernel/world with SSP enabled - default OFF. > 3) Solicit testing! > 4) After some time has passed (and people have had to reinstall libc anyways) > and enough feedback has been received flip the switch to default ON. I will change my patch to make SSP opt-out. This will address Marcel's concern too. > In light of the the recent "let's save stack space in the kernel", I'd like to > point out that SSP adds one word to every call. Not much, but still. Certainly. I would like to hear opinion from other committers if SSP should be enabled by default. > Finally, what happens if SSP triggers in the kernel? Do we get a useable > panic message? Can we get a kdb_traceback() (if compiled in)? Where is the > patch, btw? Yes, the panic message is explicit. But since a stack overflow occured, the backtrace may be corrupted. BTW the panic message warns about this. See src/sys/kern/stack_protector.c in the patch. Regards, -- Jeremie Le Hen < jeremie at le-hen dot org >< ttz at chchile dot org >
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20080418204738.GE4840>