Date: Mon, 21 Apr 2014 03:19:04 +0100 From: Jamie Landeg-Jones <jamie@dyslexicfish.net> To: rwmaillists@googlemail.com, freebsd-security@freebsd.org Subject: Re: De Raadt + FBSD + OpenSSH + hole? Message-ID: <201404210219.s3L2J4r3020038@catnip.dyslexicfish.net> In-Reply-To: <20140420220037.076be9d0@gumby.homeunix.com> References: <534B11F0.9040400@paladin.bulgarpress.com> <201404141207.s3EC7IvT085450@chronos.org.uk> <201404141232.s3ECWFQ1081178@catnip.dyslexicfish.net> <53522186.9030207@FreeBSD.org> <201404200548.s3K5mV7N055244@catnip.dyslexicfish.net> <53540307.1070708@quietfountain.com> <201404201831.s3KIVCSY054778@catnip.dyslexicfish.net> <CADgEyUt1_BiTQhvjzS0%2Bot0hUVNSUMXM8qXki%2B6dZio%2BgWfZgg@mail.gmail.com> <20140420220037.076be9d0@gumby.homeunix.com>
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RW <rwmaillists@googlemail.com> wrote: > It can return the physical memory, but there are a couple of caveats. > Firstly, it can only return whole pages. Secondly, it's not returned > instantaneously to avoid the overhead of page-faults and zeroing pages > if that region is remalloced. It's left to the page-daemon to recover > the physical memory in its own time, and it remains readable by it's > previous process until it's reassigned. Again, thanks for clearing that up for me. I wasn't all that far off-base after all, but yours and Nathans replies make sense! So there is a real world use for calloc after all! (though only as a bug catching security measure - no sane program should ever read its memory it hasn't yet written to!) cheers, jamie
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