From: Pintu Agarwal <pintu.ping@gmail.com>
To: open list <linux-kernel@vger.kernel.org>,
Kernelnewbies <kernelnewbies@kernelnewbies.org>,
"moderated list:ARM/FREESCALE IMX / MXC ARM ARCHITECTURE"
<linux-arm-kernel@lists.infradead.org>,
Russell King - ARM Linux <linux@armlinux.org.uk>,
ard.biesheuvel@linaro.org, arnd@arndb.de, nico@linaro.org,
keescook@chromium.org, thgarnie@google.com, marc.zyngier@arm.com,
Mark Rutland <mark.rutland@arm.com>,
tony@atomide.com, matt@codeblueprint.co.uk, dave.martin@arm.com
Subject: KASLR support on ARM with Kernel 4.9 and 4.14
Date: Fri, 25 Sep 2020 20:33:59 +0530 [thread overview]
Message-ID: <CAOuPNLjtG_VHL1M8-=pKNNRmWQg_8oC0YG7C8H3gQcbJ+0B3=A@mail.gmail.com> (raw)
Hi All,
This is regarding the KASLR feature support on ARM for the kernel
version 4.9 and 4.14.
Is KASLR supported on ARM-32 Linux 4.9 and above ?
Is it dependent on CONFIG_RANDOMIZE_BASE or
/proc/sys/kernel/randomize_va_space ?
Is there any relation between these two?
Is the changing kernel symbols (in every boot), only possible if KASLR
is enabled, or there is another way it can happen?
I have these queries because,
In one of the arm-32 devices with Kernel 4.14, I observed that
CONFIG_RANDOMIZE_BASE is not available.
But /proc/sys/kernel/randomize_va_space is set to 2.
However, I also observed that symbol addresses are changing in every boot.
1st boot cycle:
[root ~]# cat /proc/kallsyms | grep "sys_open"
a5b4de92 T sys_open
[root@sa515m ~]#
2nd boot cycle:
[root ~]# cat /proc/kallsyms | grep "sys_open"
f546ed66 T sys_open
So, I am wondering how this is possible without KASLR
(CONFIG_RANDOMIZE_BASE) support in Kernel ?
Similarly, with Kernel 4.9 and CONFIG_RANDOMIZE_BASE is not available
but /proc/sys/kernel/randomize_va_space is set to 2.
But here, the addresses are remaining same.
1st Run:
[root~]# cat /proc/kallsyms | grep "sys_open"
c01ed68c T sys_open
[root ~]#
*** reboot ***
[root ~]# cat /proc/kallsyms | grep "sys_open"
c01ed68c T sys_open
Is there any other difference between these two kernel versions with
respect to changing symbol addresses ?
Thanks,
Pintu
next reply other threads:[~2020-09-25 15:04 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-25 15:03 Pintu Agarwal [this message]
2020-09-25 20:26 ` KASLR support on ARM with Kernel 4.9 and 4.14 Kees Cook
2020-09-25 20:37 ` Ard Biesheuvel
2020-09-25 20:47 ` Kees Cook
2020-09-25 21:09 ` Ard Biesheuvel
2020-09-25 23:47 ` Kees Cook
2020-09-26 7:58 ` Pintu Agarwal
2020-09-26 16:40 ` Kees Cook
2020-09-28 13:45 ` Pintu Agarwal
2020-09-28 14:11 ` Pintu Agarwal
2020-09-28 19:50 ` Kees Cook
2020-09-30 13:58 ` Pintu Agarwal
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