Re: [Qemu-devel] [PATCH v3] loader: Check access size when calling rom_ptr() to avoid crashes

[Cornelia Huck <cohuck@redhat.com>]

On Mon, 25 Jun 2018 10:31:52 +0200
Thomas Huth <thuth@redhat.com> wrote:

> On 15.06.2018 11:49, Thomas Huth 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>  
> 
> Ping!
> 
> Could anybody please pick this patch up? Qemu-trivial seems to be pretty
> dormant these days (?), so maybe Paolo via misc? Or either the s390x or
> Sparc tree, since it fixes a crash on these machines?

If nobody else wants it, I can take it through the s390x tree. Would
not mind some more acks, though.