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From: Segher Boessenkool <segher@kernel.crashing.org>
To: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Xiaoming Ni <nixiaoming@huawei.com>,
	linux-kernel@vger.kernel.org, benh@kernel.crashing.org,
	mpe@ellerman.id.au, paulus@samba.org,
	linuxppc-dev@lists.ozlabs.org, yanaijie@huawei.com,
	npiggin@gmail.com, ravi.bangoria@linux.ibm.com,
	mikey@neuling.org, aneesh.kumar@linux.ibm.com,
	haren@linux.ibm.com, wangle6@huawei.com
Subject: Re: [PATCH] powerpc:Don't print raw EIP/LR hex values in dump_stack() and show_regs()
Date: Mon, 21 Dec 2020 10:31:30 -0600	[thread overview]
Message-ID: <20201221163130.GZ2672@gate.crashing.org> (raw)
In-Reply-To: <2279fc96-1f10-0c3f-64d9-734f18758620@csgroup.eu>

On Mon, Dec 21, 2020 at 04:17:21PM +0100, Christophe Leroy wrote:
> Le 21/12/2020 à 04:27, Xiaoming Ni a écrit :
> >Since the commit 2b0e86cc5de6 ("powerpc/fsl_booke/32: implement KASLR
> >infrastructure"), the powerpc system is ready to support KASLR.
> >To reduces the risk of invalidating address randomization, don't print the
> >EIP/LR hex values in dump_stack() and show_regs().

> I think your change is not enough to hide EIP address, see below a dump 
> with you patch, you get "Faulting instruction address: 0xc03a0c14"

As far as I can see the patch does nothing to the GPR printout.  Often
GPRs contain code addresses.  As one example, the LR is moved via a GPR
(often GPR0, but not always) for storing on the stack.

So this needs more work.


Segher

  reply	other threads:[~2020-12-21 16:40 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-12-21  3:27 [PATCH] powerpc:Don't print raw EIP/LR hex values in dump_stack() and show_regs() Xiaoming Ni
2020-12-21 15:17 ` Christophe Leroy
2020-12-21 16:31   ` Segher Boessenkool [this message]
2020-12-21 16:42     ` David Laight
2020-12-21 17:12       ` Segher Boessenkool
2020-12-22 13:45         ` Xiaoming Ni
2020-12-22 17:29           ` Segher Boessenkool
2020-12-22 17:45             ` Christophe Leroy

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