northbridge/intel: Out of bounds write to array in gma.h

The signature[] array in the mailbox struct opregion_header_t has
IGD_OPREGION_SIGNATURE written to it with a
sizeof(IGD_OPREGION_SIGNATURE) and not a sizeof(signature[]). This
resulted in a silent off-by-one out of bounds illegal write.

Change-Id: I651620a753c743dd2ed2af51c012c27c14a5ea25
Found-by: Coverity Scan
Signed-off-by: Edward O'Callaghan <>
Tested-by: build bot (Jenkins)
Reviewed-by: Patrick Georgi <>
4 files changed