Eclipse ThreadXでCortex-A7の範囲検査が先頭アドレスのみ確認され不正なメモリ読み書きのおそれ

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.