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Re: [PATCH] ELF: implement AT_RANDOM for future glibc use

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From: Roland McGrath <roland@...>
To: Kees Cook <kees.cook@...>
Cc: Andi Kleen <andi@...>, <linux-kernel@...>, Jakub Jelinek <jakub@...>, Ulrich Drepper <drepper@...>, <libc-alpha@...>
Subject: Re: [PATCH] ELF: implement AT_RANDOM for future glibc use
Date: Monday, October 6, 2008 - 7:58 pm

What mmap randomization and stack randomization actually use is
get_random_int(), not get_random_bytes().  This is one of those weaker
flavors seeded occasionally from the real entropy pool.  (As is, it's not a
good choice for getting 16 bytes of random at once, since it usually
returns the same 4 bytes each time when called 4 times in quick succession.)

What glibc wants is some bits with a strength of randomness chosen by the
kernel, and not to worry about the details.  I think the strength applied
to mmap and stack randomization is good enough for AT_RANDOM.


Thanks,
Roland
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Messages in current thread:
[PATCH] ELF: implement AT_RANDOM for future glibc use, Kees Cook, (Thu Oct 2, 8:16 pm)
Re: [PATCH] ELF: implement AT_RANDOM for future glibc use, Andi Kleen, (Mon Oct 6, 2:00 am)
Re: [PATCH] ELF: implement AT_RANDOM for future glibc use, Kees Cook, (Mon Oct 6, 1:50 pm)
Re: [PATCH] ELF: implement AT_RANDOM for future glibc use, Andi Kleen, (Mon Oct 6, 3:26 pm)
Re: [PATCH] ELF: implement AT_RANDOM for future glibc use, Kees Cook, (Mon Oct 6, 6:07 pm)
Re: [PATCH] ELF: implement AT_RANDOM for future glibc use, Roland McGrath, (Mon Oct 6, 7:58 pm)
Re: [PATCH] ELF: implement AT_RANDOM for future glibc use, Kees Cook, (Mon Oct 6, 8:31 pm)
Re: [PATCH] ELF: implement AT_RANDOM for future glibc use, Ulrich Drepper, (Mon Oct 6, 8:57 pm)
Re: [PATCH] ELF: implement AT_RANDOM for future glibc use, Kees Cook, (Mon Oct 6, 9:44 pm)
Re: [PATCH] ELF: implement AT_RANDOM for future glibc use, Ulrich Drepper, (Mon Oct 6, 9:51 pm)
Re: [PATCH] ELF: implement AT_RANDOM for future glibc use, Ulrich Drepper, (Mon Oct 6, 8:08 pm)
Re: [PATCH] ELF: implement AT_RANDOM for future glibc use, Andi Kleen, (Mon Oct 6, 7:28 pm)
Re: [PATCH] ELF: implement AT_RANDOM for future glibc use, Kees Cook, (Mon Oct 6, 6:01 pm)
Re: [PATCH] ELF: implement AT_RANDOM for future glibc use, Andi Kleen, (Mon Oct 6, 7:19 pm)
Re: [PATCH] ELF: implement AT_RANDOM for future glibc use, Kees Cook, (Mon Oct 6, 7:29 pm)
Re: [PATCH] ELF: implement AT_RANDOM for future glibc use, Andi Kleen, (Mon Oct 6, 7:44 pm)
Re: [PATCH] ELF: implement AT_RANDOM for future glibc use, Roland McGrath, (Thu Oct 2, 8:52 pm)
Re: [PATCH] ELF: implement AT_RANDOM for future glibc use, Kees Cook, (Fri Oct 3, 1:15 am)
Re: [PATCH] ELF: implement AT_RANDOM for future glibc use, Roland McGrath, (Fri Oct 3, 4:22 pm)
Re: [PATCH] ELF: implement AT_RANDOM for future glibc use, Jakub Jelinek, (Thu Oct 2, 8:43 pm)
[PATCH] ELF: implement AT_RANDOM for future glibc use, Kees Cook, (Fri Oct 3, 1:29 am)
Re: [PATCH] ELF: implement AT_RANDOM for future glibc use, Arjan van de Ven, (Fri Oct 3, 1:57 am)
Re: [PATCH] ELF: implement AT_RANDOM for future glibc use, Ulrich Drepper, (Fri Oct 3, 2:25 am)
[PATCH] ELF: implement AT_RANDOM for glibc PRNG seeding, Kees Cook, (Fri Oct 3, 10:50 am)
Re: [PATCH] ELF: implement AT_RANDOM for glibc PRNG seeding, Jakub Jelinek, (Fri Oct 3, 10:57 am)
[PATCH] ELF: implement AT_RANDOM for glibc PRNG seeding, Kees Cook, (Fri Oct 3, 1:33 pm)
Re: [PATCH] ELF: implement AT_RANDOM for glibc PRNG seeding, Ulrich Drepper, (Fri Oct 3, 1:41 pm)
[PATCH v5] ELF: implement AT_RANDOM for glibc PRNG seeding, Kees Cook, (Fri Oct 3, 1:59 pm)
Re: [PATCH v5] ELF: implement AT_RANDOM for glibc PRNG seeding, Andrew Morton, (Tue Oct 21, 4:01 pm)
Re: [PATCH v5] ELF: implement AT_RANDOM for glibc PRNG seeding, Ulrich Drepper, (Tue Oct 21, 4:22 pm)
Re: [PATCH v5] ELF: implement AT_RANDOM for glibc PRNG seeding, Andrew Morton, (Mon Oct 27, 1:46 am)
Re: [PATCH v5] ELF: implement AT_RANDOM for glibc PRNG seeding, Ulrich Drepper, (Sat Oct 18, 1:42 am)
Re: [PATCH] ELF: implement AT_RANDOM for glibc PRNG seeding, Ulrich Drepper, (Fri Oct 3, 10:56 am)
Re: [PATCH] ELF: implement AT_RANDOM for future glibc use, Kees Cook, (Fri Oct 3, 1:25 am)