Missing Protection for Mirrored Regions in On-Chip Fabric Firewall

Many on-chip fabrics use mirrored memory regions—duplicate copies of original data—to provide redundancy and fault tolerance. However, a critical oversight occurs when the fabric's firewall enforces access controls only on the primary region and neglects to extend those same protections to the mirrored copies. This creates a security gap where the mirrored regions become unprotected backdoors to the same sensitive data. Attackers can exploit this gap to completely bypass the intended security policy. By simply reading from or writing to the mirrored address, they can leak confidential information from the original region or corrupt its data, undermining the firewall's entire purpose. To prevent this, any firewall rule for a primary memory region must be automatically and consistently applied to all of its mirrored counterparts.