From: Yao Qi <yao@codesourcery.com>
To: Mark Kettenis <mark.kettenis@xs4all.nl>
Cc: <gdb-patches@sourceware.org>
Subject: Re: [PATCH 0/7 V2] Trust readonly sections if target has memory protection
Date: Tue, 10 Sep 2013 04:06:00 -0000 [thread overview]
Message-ID: <522E9A8A.7040509@codesourcery.com> (raw)
In-Reply-To: <201309091916.r89JGbpf009986@glazunov.sibelius.xs4all.nl>
On 09/10/2013 03:16 AM, Mark Kettenis wrote:
> What does "memory protection" mean? That a target has an MMU that
> allows pages to be marked read-only? That really is more a hardware
> feature than a OS aatribute.
"memory protection" means prevent modifying readonly sections or regions
of the process. "memory protection" is a joint effort by MMU
and OS together, IMO.
>
> Even on systems that have an MMU that can mark pages read-only, system
> calls like mprotect(2) can be used to make read-only pages
> (temporarily) writable. This is done by the OpenBSD dynamic linker
> during relocation processing. I expect other systems implementing
> strict W^X to do the same. Enabling trust-readonly-sections on such
> systems would be a bad idea.
If GDB can monitor mprotect syscall, it can still trust readonly
sections if their pages are not changed to writable by mprotect.
GDB is able to 'catch syscall mprotect', only on linux-nat
unfortunately. It doesn't work on remote target
"catch syscall" support in the remote protocol
https://sourceware.org/bugzilla/show_bug.cgi?id=13585
Similarly, GDB can monitor function VirtualProtect on Windows target
too.
--
Yao (é½å°§)
next prev parent reply other threads:[~2013-09-10 4:06 UTC|newest]
Thread overview: 62+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-09-06 2:03 [PATCH 0/3] " Yao Qi
2013-09-06 2:03 ` [PATCH 1/3] set trust-readonly-sections off in test cases Yao Qi
2013-09-06 5:56 ` Eli Zaretskii
2013-09-06 17:23 ` Pedro Alves
2013-09-06 2:03 ` [PATCH 2/3] Trust readonly sections if target has memory protection Yao Qi
2013-09-06 6:05 ` Eli Zaretskii
2013-09-06 9:07 ` Yao Qi
2013-09-06 9:24 ` Eli Zaretskii
2013-09-06 2:03 ` [PATCH 3/3] Linux " Yao Qi
2013-09-06 5:57 ` [PATCH 0/3] Trust readonly sections if target " Eli Zaretskii
2013-09-06 8:24 ` Yao Qi
2013-09-06 8:45 ` Eli Zaretskii
2013-09-06 13:03 ` Joel Brobecker
2013-09-06 13:27 ` Yao Qi
2013-09-06 13:32 ` Eli Zaretskii
2013-09-06 14:17 ` Pierre Muller
[not found] ` <"000d01ceab0b$d53ae600$7fb0b200$@muller"@ics-cnrs.unistra.fr>
2013-09-06 14:38 ` Eli Zaretskii
2013-09-06 14:52 ` Joel Brobecker
2013-09-06 15:56 ` Eli Zaretskii
2013-09-06 18:10 ` Joel Brobecker
2013-09-06 18:36 ` Eli Zaretskii
2013-09-06 13:00 ` Joel Brobecker
2013-09-08 12:04 ` [PATCH 0/7 V2] " Yao Qi
2013-09-08 12:04 ` [PATCH 1/7] Emit a warning when writing to a readonly section and trust_readonly is true Yao Qi
2013-09-08 15:10 ` Eli Zaretskii
2013-09-08 12:05 ` [PATCH 2/7] set trust-readonly-sections off in test cases Yao Qi
2013-09-08 12:05 ` [PATCH 7/7] Windows has memory protection Yao Qi
2013-09-08 12:05 ` [PATCH 4/7] Trust readonly sections if target " Yao Qi
2013-09-08 15:13 ` Eli Zaretskii
2013-09-09 7:49 ` Yao Qi
2013-09-09 16:25 ` Eli Zaretskii
2013-09-08 12:05 ` [PATCH 3/7] New function windows_init_abi Yao Qi
2013-09-08 12:05 ` [PATCH 6/7] Linux has memory protection Yao Qi
2013-09-08 12:05 ` [PATCH 5/7] DOC and NEWS Yao Qi
2013-09-09 19:16 ` [PATCH 0/7 V2] Trust readonly sections if target has memory protection Mark Kettenis
2013-09-10 4:06 ` Yao Qi [this message]
2013-09-12 8:30 ` Yao Qi
2013-09-12 9:49 ` Mark Kettenis
2013-09-13 8:17 ` Yao Qi
2013-09-30 17:50 ` Pedro Alves
2013-09-30 18:08 ` Pedro Alves
2013-10-07 22:29 ` Stan Shebs
2013-10-08 12:18 ` Pedro Alves
2013-10-08 12:47 ` Abid, Hafiz
2013-10-08 13:36 ` tmirza
2013-10-09 2:24 ` Doug Evans
2013-10-23 10:16 ` Yao Qi
2013-10-15 0:44 ` Yao Qi
2013-09-20 2:47 ` [PATCH 0/7 V3] " Yao Qi
2013-09-20 2:47 ` [PATCH 4/7] Trust readonly sections if target has memory protection and in remote debugging Yao Qi
2013-09-20 2:47 ` [PATCH 1/7] Emit a query when writing to a readonly section and trust_readonly is true Yao Qi
2013-09-20 2:47 ` [PATCH 7/7] Windows has memory protection Yao Qi
2013-09-20 2:47 ` [PATCH 3/7] New function windows_init_abi Yao Qi
2013-09-30 18:23 ` Pedro Alves
2013-10-01 6:47 ` Yao Qi
2013-10-01 9:35 ` Pedro Alves
2013-10-01 13:23 ` Yao Qi
2013-09-20 2:47 ` [PATCH 5/7] DOC and NEWS Yao Qi
2013-09-20 8:21 ` Eli Zaretskii
2013-09-20 2:47 ` [PATCH 2/7] set trust-readonly-sections off in test cases Yao Qi
2013-09-20 2:47 ` [PATCH 6/7] Linux has memory protection Yao Qi
2013-09-29 13:51 ` [PATCH 0/7 V3] Trust readonly sections if target " Yao Qi
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