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Re: [PATCH] Undo some of the pseudo-security madness

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From: Arjan van de Ven <arjan@...>
To: Samium Gromoff <_deepfire@...>
Cc: Pavel Machek <pavel@...>, <Valdis.Kletnieks@...>, David Wagner <daw@...>, <linux-kernel@...>
Subject: Re: [PATCH] Undo some of the pseudo-security madness
Date: Wednesday, January 31, 2007 - 5:59 am

> No amount of carefulness will prevent vendors stick arbitrarily

MAP_FIXED is useful still. The only safe way is to use addresses you got
from mmap(), eg you overmap something.
Anything else is madness, with or without randomization. The C library
for example is free, and does, allocate memory and stacks etc etc.

Same for many other libraries; in addition libraries change in size all
the time... MAP_FIXED of an address you don't KNOW is free is a bug.
Period.
(using an address previously obtained from mmap() is safest, but you
could in theory also parse /proc/self/maps, although that is racey,
since nothing guarantees that the C library didn't spawn a background
thread that allocates memory)


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Messages in current thread:
Re: [PATCH] Undo some of the pseudo-security madness, Samium Gromoff, (Sun Jan 21, 7:23 pm)
Re: [PATCH] Undo some of the pseudo-security madness, , (Mon Jan 22, 11:20 am)
Re: [PATCH] Undo some of the pseudo-security madness, Samium Gromoff, (Mon Jan 22, 1:39 pm)
Re: [PATCH] Undo some of the pseudo-security madness, Pavel Machek, (Tue Jan 23, 4:48 am)
Re: [PATCH] Undo some of the pseudo-security madness, Samium Gromoff, (Tue Jan 23, 10:03 am)
Re: [PATCH] Undo some of the pseudo-security madness, Arjan van de Ven, (Wed Jan 31, 5:59 am)
Re: [PATCH] Undo some of the pseudo-security madness, Florian Weimer, (Thu Feb 1, 4:05 am)
Re: [PATCH] Undo some of the pseudo-security madness, Alan, (Tue Jan 23, 11:41 am)
Re: [PATCH] Undo some of the pseudo-security madness, Florian Weimer, (Sat Feb 24, 5:51 am)
Re: [PATCH] Undo some of the pseudo-security madness, Samium Gromoff, (Sat Feb 24, 9:36 am)
[PATCH 2/2] Make the EF_AS_NO_RANDOM e_flag bit disable PF_R..., Samium Gromoff, (Tue Jan 23, 4:31 pm)
[PATCH 1/2] Define the EF_AS_NO_RANDOM e_flag bit, Samium Gromoff, (Tue Jan 23, 4:28 pm)
Re: [PATCH 1/2] Define the EF_AS_NO_RANDOM e_flag bit, Arjan van de Ven, (Sun Jan 28, 9:18 pm)
Re: [PATCH 1/2] Define the EF_AS_NO_RANDOM e_flag bit, Jakub Jelinek, (Tue Jan 23, 4:50 pm)
Re: [PATCH 1/2] Define the EF_AS_NO_RANDOM e_flag bit, Samium Gromoff, (Tue Jan 23, 5:06 pm)
Re: [PATCH 1/2] Define the EF_AS_NO_RANDOM e_flag bit, Jakub Jelinek, (Tue Jan 23, 5:16 pm)
Re: [PATCH 1/2] Define the EF_AS_NO_RANDOM e_flag bit, Samium Gromoff, (Tue Jan 23, 7:21 pm)
Re: [PATCH 1/2] Define the EF_AS_NO_RANDOM e_flag bit, Pavel Machek, (Wed Jan 24, 1:08 pm)
Re: [PATCH 1/2] Define the EF_AS_NO_RANDOM e_flag bit, Samium Gromoff, (Tue Jan 23, 5:54 pm)
[PATCH 0/2] Mechanism to turn of ASR on a per-ELF binary basis, Samium Gromoff, (Tue Jan 23, 4:21 pm)