Date: Wed, 2 Sep 1998 07:15:51 +0000 (GMT) From: Terry Lambert <tlambert@primenet.com> To: jdp@polstra.com (John Polstra) Cc: bde@zeta.org.au, reilly@zeta.org.au, current@FreeBSD.ORG Subject: Re: ELF binaries size Message-ID: <199809020715.AAA22302@usr02.primenet.com> In-Reply-To: <199809020221.TAA17213@austin.polstra.com> from "John Polstra" at Sep 1, 98 07:21:07 pm
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> > I think it implies that elf wastes a full page of memory (the space > > between the ':'s above) most of the time (unless the ':'s are on a > > page boundary), while aout only wastes an average of half a page > > (the space between the text ':' and the end of the page). > > But a.out has a repeat of the same situation at the juncture of data > and bss, and ELF does not. In the disk image rather than in the memory image. I think Bruce is mistaking the dual mapping for a single mapping, on the theory that in a unified VM and buffer cache, there can be only one instance of a page hung off the VP. Bruce should look at the ELF (and COFF) loaders. > It's moot on the i386, if I remember correctly. Doesn't execute > permission imply read permission on the i386? > > Also, how does it enhance security to prevent a program from reading > its own text segment? If a program doesn't want to read its text > segment then it should simply ... not read it. :-) Good reason to not use an Intel processor... Consider the case of a program of permission --x--x--x... This "security through obscurity" is bogus, in any case. Terry Lambert terry@lambert.org --- Any opinions in this posting are my own and not those of my present or previous employers. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message
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