The Cortex-A7 MMU Modules port validates a caller-supplied buffer by translating **one address** — the first byte. The common Module Manager

The Cortex-A7 MMU Modules port validates a caller-supplied buffer by translating one address — the first byte. The common Module Manager hands its range check the module instance, the start address and the complete byte size; the Cortex-A7 implementation discarded the instance and the size and asked the MMU a single question about the start.

A memory-protected module therefore passed any range whose first byte was user-readable, however far the rest of it reached. Privileged dispatch code then read or wrote the whole range. Because every protected-module dispatcher that consumes a buffer or an extra-parameter array goes through this one macro, the defect is not in any individual service: it is in the primitive all of them rely on.