From: Scott Wood <oss@buserror.net>
To: Jason Yan <yanaijie@huawei.com>,
mpe@ellerman.id.au, linuxppc-dev@lists.ozlabs.org,
diana.craciun@nxp.com, christophe.leroy@c-s.fr,
benh@kernel.crashing.org, paulus@samba.org, npiggin@gmail.com,
keescook@chromium.org, kernel-hardening@lists.openwall.com
Cc: wangkefeng.wang@huawei.com, linux-kernel@vger.kernel.org,
jingxiangfeng@huawei.com, zhaohongjiang@huawei.com,
thunder.leizhen@huawei.com, fanchengyang@huawei.com,
yebin10@huawei.com
Subject: Re: [PATCH v6 00/12] implement KASLR for powerpc/fsl_booke/32
Date: Tue, 27 Aug 2019 23:05:30 -0500 [thread overview]
Message-ID: <a39b81562bcdeda7ffe0c2c29a60ff08c77047a6.camel@buserror.net> (raw)
In-Reply-To: <20190809100800.5426-1-yanaijie@huawei.com>
On Fri, 2019-08-09 at 18:07 +0800, Jason Yan wrote:
> This series implements KASLR for powerpc/fsl_booke/32, as a security
> feature that deters exploit attempts relying on knowledge of the location
> of kernel internals.
>
> Since CONFIG_RELOCATABLE has already supported, what we need to do is
> map or copy kernel to a proper place and relocate.
Have you tested this with a kernel that was loaded at a non-zero address? I
tried loading a kernel at 0x04000000 (by changing the address in the uImage,
and setting bootm_low to 04000000 in U-Boot), and it works without
CONFIG_RANDOMIZE and fails with.
> Freescale Book-E
> parts expect lowmem to be mapped by fixed TLB entries(TLB1). The TLB1
> entries are not suitable to map the kernel directly in a randomized
> region, so we chose to copy the kernel to a proper place and restart to
> relocate.
>
> Entropy is derived from the banner and timer base, which will change every
> build and boot. This not so much safe so additionally the bootloader may
> pass entropy via the /chosen/kaslr-seed node in device tree.
How complicated would it be to directly access the HW RNG (if present) that
early in the boot? It'd be nice if a U-Boot update weren't required (and
particularly concerning that KASLR would appear to work without a U-Boot
update, but without decent entropy).
-Scott
next prev parent reply other threads:[~2019-08-29 12:05 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-09 10:07 [PATCH v6 00/12] implement KASLR for powerpc/fsl_booke/32 Jason Yan
2019-08-09 10:07 ` [PATCH v6 01/12] powerpc: unify definition of M_IF_NEEDED Jason Yan
2019-08-09 10:07 ` [PATCH v6 02/12] powerpc: move memstart_addr and kernstart_addr to init-common.c Jason Yan
2019-08-09 10:07 ` [PATCH v6 03/12] powerpc: introduce kernstart_virt_addr to store the kernel base Jason Yan
2019-08-09 10:07 ` [PATCH v6 04/12] powerpc/fsl_booke/32: introduce create_tlb_entry() helper Jason Yan
2019-08-27 22:07 ` Scott Wood
2019-08-28 5:33 ` Jason Yan
2019-08-09 10:07 ` [PATCH v6 05/12] powerpc/fsl_booke/32: introduce reloc_kernel_entry() helper Jason Yan
2019-08-09 10:07 ` [PATCH v6 06/12] powerpc/fsl_booke/32: implement KASLR infrastructure Jason Yan
2019-08-28 4:54 ` Scott Wood
2019-08-28 5:47 ` Christophe Leroy
2019-08-29 6:26 ` Jason Yan
2019-08-28 11:03 ` Jason Yan
2019-08-28 16:44 ` Scott Wood
2019-08-09 10:07 ` [PATCH v6 07/12] powerpc/fsl_booke/32: randomize the kernel image offset Jason Yan
2019-08-09 10:07 ` [PATCH v6 08/12] powerpc/fsl_booke/kaslr: clear the original kernel if randomized Jason Yan
2019-08-09 10:07 ` [PATCH v6 09/12] powerpc/fsl_booke/kaslr: support nokaslr cmdline parameter Jason Yan
2019-08-09 10:07 ` [PATCH v6 10/12] powerpc/fsl_booke/kaslr: dump out kernel offset information on panic Jason Yan
2019-08-09 10:07 ` [PATCH v6 11/12] powerpc/fsl_booke/kaslr: export offset in VMCOREINFO ELF notes Jason Yan
2019-08-09 10:08 ` [PATCH v6 12/12] powerpc/fsl_booke/32: Document KASLR implementation Jason Yan
2019-08-19 6:12 ` [PATCH v6 00/12] implement KASLR for powerpc/fsl_booke/32 Jason Yan
2019-08-27 0:39 ` Jason Yan
2019-08-27 1:33 ` Michael Ellerman
2019-08-28 5:08 ` Scott Wood
2019-08-28 13:01 ` Michael Ellerman
2019-08-28 4:05 ` Scott Wood [this message]
2019-08-28 4:59 ` Scott Wood
2019-08-29 2:41 ` Jason Yan
2019-08-29 1:57 ` Jason Yan
2019-09-10 5:34 ` Jason Yan
2019-09-14 14:28 ` Scott Wood
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=a39b81562bcdeda7ffe0c2c29a60ff08c77047a6.camel@buserror.net \
--to=oss@buserror.net \
--cc=benh@kernel.crashing.org \
--cc=christophe.leroy@c-s.fr \
--cc=diana.craciun@nxp.com \
--cc=fanchengyang@huawei.com \
--cc=jingxiangfeng@huawei.com \
--cc=keescook@chromium.org \
--cc=kernel-hardening@lists.openwall.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linuxppc-dev@lists.ozlabs.org \
--cc=mpe@ellerman.id.au \
--cc=npiggin@gmail.com \
--cc=paulus@samba.org \
--cc=thunder.leizhen@huawei.com \
--cc=wangkefeng.wang@huawei.com \
--cc=yanaijie@huawei.com \
--cc=yebin10@huawei.com \
--cc=zhaohongjiang@huawei.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).