The firewall in an on-chip fabric protects the main addressed region, but it does not protect any mirrored memory or memory-mapped-IO (MMIO) regions.
Few fabrics mirror memory and address ranges, where mirrored regions contain copies of the original data. This redundancy is used to achieve fault tolerance. Whatever protections the fabric firewall implements for the original region should also apply to the mirrored regions. If not, an attacker could bypass existing read/write protections by reading from/writing to the mirrored regions to leak or corrupt the original data.
Threat Mapped score: 0.0
Industry: Finiancial
Threat priority: Unclassified
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| Phase | Note |
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| Architecture and Design | N/A |
| Implementation | N/A |
Intro: A memory-controller IP block is connected to the on-chip fabric in a System on Chip (SoC). The memory controller is configured to divide the memory into four parts: one original and three mirrored regions inside the memory. The upper two bits of the address indicate which region is being addressed. 00 indicates the original region and 01, 10, and 11 are used to address the mirrored regions. All four regions operate in a lock-step manner and are always synchronized. The firewall in the on-chip fabric is programmed to protect the assets in the memory.
Body: The firewall only protects the original range but not the mirrored regions.