From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from sipsolutions.net (crystal.sipsolutions.net [195.210.38.204]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTP id 1955DDDF66 for ; Fri, 6 Jul 2007 21:17:46 +1000 (EST) Subject: Re: Executing from readablee, no-exec pages From: Johannes Berg To: Scott Wood In-Reply-To: <468D68D4.4050704@freescale.com> References: <468D68D4.4050704@freescale.com> Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="=-MICaiwHOITc0IYF30xqA" Date: Fri, 06 Jul 2007 13:18:42 +0200 Message-Id: <1183720722.3818.126.camel@johannes.berg> Mime-Version: 1.0 Cc: linuxppc-dev@ozlabs.org, paulus@samba.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , --=-MICaiwHOITc0IYF30xqA Content-Type: text/plain Content-Transfer-Encoding: quoted-printable On Thu, 2007-07-05 at 16:55 -0500, Scott Wood wrote: > As revealed by the recent "Prevent data exception in kernel space"=20 > patch, versions of glibc prior to 2.4[1] assume that, on powerpc32, they=20 > can execute out of any readable mapping, regardless of whether it is=20 > marked for execution. This happens in the elf_machine_load_address()=20 > function. Umm, are you sure about this? The "prevent data exception in kernel space" patch came from a test program I had that attempted to execute a page with /no permissions/ at all! I know that I used to have problems with mono making this assumption but these have since been fixed; however if I understand you correctly then you can always pre-fault the page by a read and then execute it so I don't see the point in not doing the change you suggest. johannes --=-MICaiwHOITc0IYF30xqA Content-Type: application/pgp-signature; name=signature.asc Content-Description: This is a digitally signed message part -----BEGIN PGP SIGNATURE----- Comment: Johannes Berg (powerbook) iD8DBQBGjiUS/ETPhpq3jKURAskPAJsF+KIoSlt45mKRYKi3K8l0xNuoNwCfZBsS z2f+zpMRrGl0VVxu+YiqN3Y= =qBMJ -----END PGP SIGNATURE----- --=-MICaiwHOITc0IYF30xqA--