From: Alexander Boettcher <alexander.boettcher@genode-labs.com>
To: The development of GNU GRUB <grub-devel@gnu.org>,
Daniel Kiper <dkiper@net-space.pl>
Subject: Re: [PATCH] mbi: use per segment a separate relocator chunk
Date: Tue, 15 May 2018 21:18:18 +0200 [thread overview]
Message-ID: <a5ab4886-41ec-7bf6-faa7-271e22289a83@genode-labs.com> (raw)
In-Reply-To: <bfc23ccf-4fbb-d4f5-f4dd-560cd43be6f0@genode-labs.com>
On 15.05.2018 21:10, Alexander Boettcher wrote:
>> I assume that a given ELF PHDR address/size does not cover VGA memory or
>> anything like that,
>
> No.
>
>> so, I am not sure what exactly overwrites this region.
>> grub_memset() in current line 161 at some point?
>
> No. During grub_relocator_prepare_reloc the overwrite happens, if i'm
> not wrong.
>
> An (artificial) example, imagine two ELF PHDRs, e.g.
>
> [0x8000-0x9000) and
> [0x2000000-0x2100000).
>
> Without this patch grub calculates one relocator chunk of size 0x20f8000
> (0x2100000 - 0x8000) and places it at some higher memory, e.g.
> [0x3000000 - 0x30f8000). During the invocation of
Must be [0x3000000-0x50f8000)
> grub_relocator_prepare_reloc the memory gets copied from
>
> [0x3000000-0x30f8000) to [0x8000-0x2100000)
Must be [0x3000000-0x50f8000) to [0x8000-0x2100000)
Sorry.
--
Alexander Boettcher
Genode Labs
http://www.genode-labs.com - http://www.genode.org
Genode Labs GmbH - Amtsgericht Dresden - HRB 28424 - Sitz Dresden
Geschäftsführer: Dr.-Ing. Norman Feske, Christian Helmuth
next prev parent reply other threads:[~2018-05-15 19:18 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-14 19:02 [PATCH] mbi: use per segment a separate relocator chunk Alexander Boettcher
2018-05-15 13:42 ` Daniel Kiper
2018-05-15 19:10 ` Alexander Boettcher
2018-05-15 19:18 ` Alexander Boettcher [this message]
2018-05-16 10:22 ` Daniel Kiper
2018-06-05 19:59 ` Alexander Boettcher
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