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Date: Tue, 26 Jun 2018 10:56:25 +0200
From: Cornelia Huck <cohuck@redhat.com>
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Subject: Re: [Qemu-devel] [qemu-s390x] [PATCH v3] loader: Check access size
 when calling rom_ptr() to avoid crashes
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To: Thomas Huth <thuth@redhat.com>
Cc: Peter Maydell <peter.maydell@linaro.org>, qemu-trivial@nongnu.org, Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>, qemu-devel@nongnu.org, Christian Borntraeger <borntraeger@de.ibm.com>, qemu-s390x@nongnu.org, qemu-arm@nongnu.org, Artyom Tarasenko <atar4qemu@gmail.com>, Paolo Bonzini <pbonzini@redhat.com>, Yongbok Kim <yongbok.kim@mips.com>, Aurelien Jarno <aurelien@aurel32.net>

On Tue, 26 Jun 2018 10:55:09 +0200
Thomas Huth <thuth@redhat.com> wrote:

> On 26.06.2018 10:40, Cornelia Huck wrote:
> > On Fri, 15 Jun 2018 11:49:05 +0200
> > Thomas Huth <thuth@redhat.com> wrote:
> >   
> >> The rom_ptr() function allows direct access to the ROM blobs that we
> >> load during startup. However, there are currently no checks for the
> >> size of the accesses, so it's currently possible to crash QEMU for
> >> example with:
> >>
> >> $ echo "Insane in the mainframe" > /tmp/test.txt
> >> $ s390x-softmmu/qemu-system-s390x -kernel /tmp/test.txt -append xyz
> >> Segmentation fault (core dumped)
> >> $ s390x-softmmu/qemu-system-s390x -kernel /tmp/test.txt -initrd /tmp/test.txt
> >> Segmentation fault (core dumped)
> >> $ echo -n HdrS > /tmp/hdr.txt
> >> $ sparc64-softmmu/qemu-system-sparc64 -kernel /tmp/hdr.txt -initrd /tmp/hdr.txt
> >> Segmentation fault (core dumped)
> >>
> >> We need a possibility to check the size of the ROM area that we want
> >> to access, thus let's add a size parameter to the rom_ptr() function
> >> to avoid these problems.
> >>
> >> Signed-off-by: Thomas Huth <thuth@redhat.com>  
> > 
> > Grmpf, this conflicts with "s390/ipl: fix ipl with -no-reboot" in
> > s390-next... do you want to rebase it?  
> 
> Really? Where is the conflict? I can rebase my patch to your s390-next
> branch, but the patch looks identical after that rebase. As far as I can
> see, the patches only change different parts of the ipl.c file.

Yes, but the result does not compile :)