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From: Tobias Karnat <tobias.karnat@googlemail.com>
To: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 3/3 V13] RO/NX protection for loadable kernel
Date: Mon, 03 Jan 2011 13:46:42 +0100	[thread overview]
Message-ID: <1294058802.19182.28.camel@Tobias-Karnat> (raw)

> Sure.  I can verify that the patch series (a) doesn't break well-behaved
> modules and (b) it *does* trigger for misbehaving modules (I sent the
> VirtualBox crew a bug report for a module that tried to write to an area
> marked executable).

This seems to be fixed by VirtualBox 4.

I applied the patchset to 2.6.36.
('All in one' patch, http://pastebin.com/raw.php?i=6CDnAkjP )

I have however noticed that after enabling;
CONFIG_DEBUG_KERNEL, CONFIG_DEBUG_RODATA and CONFIG_DEBUG_SET_MODULE_RONX
there are three "Freeing unused kernel memory" messages, is this correct?

Before applying patch:
[    1.449499] Freeing initrd memory: 16328k freed
[    3.336464] Freeing unused kernel memory: 844k freed

After applying patch:
[    1.449262] Freeing initrd memory: 16328k freed
[    3.297901] Freeing unused kernel memory: 844k freed
[    3.311849] Write protecting the kernel read-only data: 8192k
[    3.327592] Freeing unused kernel memory: 448k freed
[    3.342651] Freeing unused kernel memory: 276k freed

And why does CONFIG_DEBUG_RODATA depend on CONFIG_DEBUG_KERNEL;
Isn't it primarily a security enhancement?

-Tobias


             reply	other threads:[~2011-01-03 12:46 UTC|newest]

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-01-03 12:46 Tobias Karnat [this message]
  -- strict thread matches above, loose matches on Subject: below --
2010-11-16 21:35 [PATCH 3/3 V13] RO/NX protection for loadable kernel matthieu castet
2010-11-25  3:41 ` Valdis.Kletnieks
2010-11-26 17:23   ` mat
2010-11-29 16:59     ` Valdis.Kletnieks
2010-12-08 22:19     ` Kees Cook
2010-12-10 23:18       ` mat
2010-12-11  0:27         ` Kees Cook
     [not found]           ` <20101211115735.21b616fe@mat-laptop>
2010-12-11 23:15             ` Kees Cook
2010-12-22 12:40         ` Ingo Molnar
2010-12-22 21:35           ` Valdis.Kletnieks
2010-12-22 21:57             ` Ingo Molnar
2010-12-22 22:02               ` Steven Rostedt
2010-12-23  8:49                 ` Ingo Molnar
2010-12-23 15:01             ` Steven Rostedt
2010-12-24  1:43               ` Valdis.Kletnieks
2011-01-07  9:34             ` Xiaotian Feng
2011-01-07 13:04               ` Ingo Molnar
2011-01-08 11:24                 ` matthieu castet
2011-01-10 23:49                   ` Kees Cook
2011-01-11 22:42                     ` matthieu castet
2011-01-20 20:32               ` matthieu castet
2011-01-21  2:35                 ` Xiaotian Feng
2010-11-29 18:15 ` Steven Rostedt
2010-11-29 23:35   ` Rusty Russell
2010-11-30 14:46     ` Steven Rostedt
2010-12-01 13:36       ` Rusty Russell
2010-11-30 21:20   ` mat
2010-12-01  0:38     ` Steven Rostedt

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