scsi: lsi: exit infinite loop while executing script (CVE-2019-12068)

scsi: lsi: exit infinite loop while executing script (CVE-2019-12068)

When executing script in lsi_execute_script(), the LSI scsi adapter
emulator advances 's->dsp' index to read next opcode. This can lead
to an infinite loop if the next opcode is empty. Move the existing
loop exit after 10k iterations so that it covers no-op opcodes as
well.

Reported-by: Bugs SysSec <bugs-syssec@rub.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Prasad J Pandit <pjp@fedoraproject.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
(cherry picked from commit de594e47659029316bbf9391efb79da0a1a08e08)
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>