Date: Fri, 24 Jul 2009 14:58:30 +0300 From: Kostik Belousov <kostikbel@gmail.com> To: Jeremie Le Hen <jeremie@le-hen.org> Cc: Ed Schouten <ed@80386.nl>, FreeBSD Hackers <freebsd-hackers@freebsd.org> Subject: Re: concurrent sysctl implementation Message-ID: <20090724115830.GG55190@deviant.kiev.zoral.com.ua> In-Reply-To: <20090724115404.GI54986@felucia.tataz.chchile.org> References: <a0806f900905050107u4cbf0624oc83aafa54ae651f0@mail.gmail.com> <d9f479c10905050239u5d6d8304y1f63e41eabee8624@mail.gmail.com> <20090508214117.GY58540@hoeg.nl> <20090509113459.GD56667@e.0x20.net> <20090509121313.GA58540@hoeg.nl> <20090724073451.GH54986@felucia.tataz.chchile.org> <20090724081842.GF55190@deviant.kiev.zoral.com.ua> <20090724115404.GI54986@felucia.tataz.chchile.org>
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--30ciY2VPQam4VdV2 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Fri, Jul 24, 2009 at 01:54:04PM +0200, Jeremie Le Hen wrote: > On Fri, Jul 24, 2009 at 11:18:42AM +0300, Kostik Belousov wrote: > > On Fri, Jul 24, 2009 at 09:34:51AM +0200, Jeremie Le Hen wrote: > > > Hi Ed, > > >=20 > > > Sorry for the late reply. > > >=20 > > > On Sat, May 09, 2009 at 02:13:13PM +0200, Ed Schouten wrote: > > > > We probably could. I think I discussed this with Robert Watson some= time > > > > ago and we could use things like ELF hints. But still, that doesn't > > > > prevent us from reaching this limitation later on. > > >=20 > > > Can you elaborate a little? Are you talking about elf-hints.h? > > > I don't see where we can get randomness from it. > >=20 > > The thing is called ELF auxillary information vector. It is used to > > supply some useful information for interpreter from the kernel, > > see include/machine/elf.h for AT_* entries. >=20 > Ah ok, so the idea is to generate a new hint, for instance AT_RANDOM, > generated at link time, that will be used to fill the canary at exec(2) > time? The aux entries are not hints, and they are put on the new image stack when execve() activates the image. Aux entries has nothing to do with static link time, they are supplied to the dynamic linker (ELF interpreter). --30ciY2VPQam4VdV2 Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.9 (FreeBSD) iEYEARECAAYFAkppoeUACgkQC3+MBN1Mb4hsygCeMNL7SXmv25mmZdbu/8cgND1O BOgAn1sXD1u8n5ZRXtNkDV0sfgF/LEYx =zGSc -----END PGP SIGNATURE----- --30ciY2VPQam4VdV2--
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