Northcape

Northcape Capability Resolver Cache

Description

Northcape is a novel least-privilege byte-granular capability-based memory access control scheme for software and hardware devices, developed at the research group. As Northcape currently targets real-time systems only, it does not cache capability metadata table entries. Thus, for every capability lookup, it needs to perform n memory requests (with n being the hierarchie height). This is akin to page-table walking in paging-based memory systems. While this is acceptable (and intended behavior) for real-time systems, general-purpose systems might be bottlenecked by the memory accesses. CPUs use the equivalent problem in paging with a translation lookaside buffer (TLB), a small cache that speeds up page table walking by mapping virtual to physical addresses. Analogously, the Northcape Capability Resolver could benefit from a cache.
Sep 30, 2024
Safe Sharing of (Ethernet) Peripherals across enclaves

Description

Enclaves running in trusted execution environments might want to have direct control over peripherals such as network interface cards or accelerators. While making the device accessible to an enclave is often supported in hardware, sharing it between two enclaves comes with unique challenges. In particular, as devices are under the enclaves’ full control, no restrictions on their use of the devices can be enforced. This means that, e.g., one enclave can impersonate the network identity of another device by spooding its MAC and IP addresses or attempt to steal data from other enclaves’ computations from an accelerator device. Also, enclaves might attempt abuse DMA capabilities of devices to steal data from other enclaves. State-of-the-art solutions to this problem usually rely on trusted software that resets the device during context switches from one enclave to another to mitigate data leakage (CURE) in conjunction with memory access control or encryption, while use cases such as network policies for the enclaves usually require dedicating one interface port to each enclave.
Sep 30, 2024