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Re: Encoding page size in the ELF header
- From: Florian Weimer <fweimer at redhat dot com>
- To: Andreas Schwab <schwab at linux-m68k dot org>, Rich Felker <dalias at libc dot org>
- Cc: "Frank Ch. Eigler" <fche at redhat dot com>, "Carlos O'Donell" <carlos at redhat dot com>, GNU C Library <libc-alpha at sourceware dot org>
- Date: Sun, 27 Sep 2015 11:02:42 +0200
- Subject: Re: Encoding page size in the ELF header
- Authentication-results: sourceware.org; auth=none
- References: <56054662 dot 2010106 at redhat dot com> <56059DD4 dot 1080908 at redhat dot com> <5605A084 dot 4010501 at redhat dot com> <y0mtwqgwz9f dot fsf at fche dot csb> <20150927052523 dot GP17773 at brightrain dot aerifal dot cx> <m2si60tf6e dot fsf at linux-m68k dot org>
On 09/27/2015 10:55 AM, Andreas Schwab wrote:
> Rich Felker <dalias@libc.org> writes:
>
>> On Sat, Sep 26, 2015 at 07:13:00PM -0400, Frank Ch. Eigler wrote:
>>> Could the app more portably use
>>>
>>> int critical_data __attribute__((section(".data.critical")));
>>>
>>> and maybe a linker script widgetry to assure padding & fetch
>>> base-addresses, and then mprotect it that way? It would become
>>> independent of page size.
>>
>> That does not eliminate the page size dependency.
>
> MAXPAGESIZE is available in the linker script.
But ld.so supports running binaries with a larger kernel page size than
MAXPAGESIZE, don't we? In most cases, it does work, after all.
--
Florian Weimer / Red Hat Product Security