roms: assert if max rom size is less than the used size

It would ensure that we would notice attempt to write beyond
the allocated buffer. In case of MemoryRegion backed ROM it's
the host buffer and the guest RAM otherwise.

assert can be triggered with:
  dd if=/dev/zero of=/tmp/blob bs=63k count=1
  qemu-system-x86_64 `for  i in {1..33}; do echo -n " -acpitable /tmp/blob"; done`

Fixes: (a1666142db acpi-build: make ROMs RAM blocks resizeable)

Reported-by: Wei Yang <richardw.yang@linux.intel.com>
Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Message-Id: <1554982098-336210-1-git-send-email-imammedo@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Igor Mammedov 2019-04-11 13:28:18 +02:00 committed by Paolo Bonzini
parent b92be8d092
commit 85fad7e115

View File

@ -1025,6 +1025,7 @@ MemoryRegion *rom_add_blob(const char *name, const void *blob, size_t len,
rom->addr = addr;
rom->romsize = max_len ? max_len : len;
rom->datasize = len;
g_assert(rom->romsize >= rom->datasize);
rom->data = g_malloc0(rom->datasize);
memcpy(rom->data, blob, len);
rom_insert(rom);