Pointer Provenance in a Capability Architecture

We design and implement a framework for tracking pointer provenance, using our CHERI fat-pointer capability architec- ture to facilitate analysis of security implications of program pointer flows in both user and privileged code, with mini- mal instrumentation. CHERI enforces pointer provenance validity at the architectural level, in the presence of complex pointer arithmetic and type casting. CHERI present new op- portunities for provenance research: we discuss use cases and highlight lessons and open questions from our work.DARPA/AFRL FA8750-10-C-0237, Google Chrome University Research Program Awar

The Broadband Phone Network: Experiences with Context-Aware Telephony CUED/F − INF ENG/T R.533

We introduce the Broadband Phone, a Voice-over-IP (VoIP) based phone which integrates a high-resolution, touch-sensitive LCD screen. The Broadband Phone Network features: (i) a thin-client network architecture enabling easy integration into the sentient environment at the Anonymous University; (ii) location-sensing via the Active Bat indoor location system allowing applications such as the “follow-me phone”; and (iii) location-based handover of Bluetooth connections, enabling integration of the users ’ own personal mobile phones. We describe the thin-client network architecture, the applications which use it such as the new dialing mechanisms, and also how the Broadband Phone can be used as a peripheral display. Finally, we relate our experiences with more than a year of operating this phone network and discuss the pros and cons of our approach.

An analysis of hard drive energy consumption

previous version of the paper regarding write energy consumptio

IPAPI: Designing an Improved Provenance API

Abstract We investigate the main limitations imposed by existing provenance systems in the development of provenanceaware applications. In the case of disclosed provenance APIs, most of those limitations can be traced back to the inability to integrate provenance from different sources, layers and of different granularities into a coherent view of data production. We consider possible solutions in the design of an Improved Provenance API (IPAPI), based on a general model of how different system entities interact to generate, accumulate or propagate provenance. The resulting architecture enables a whole new range of provenance capture scenarios, for which available APIs do not provide adequate support

Melange: Creating a ”functional” internet

Most implementations of critical Internet protocols are written in type-unsafe languages such as C or C++ and are regularly vulnerable to serious security and reliability problems. Type-safe languages eliminate many errors but are not used to due to the perceived performance overheads. We combine two techniques to eliminate this performance penalty in a practical fashion: strong static typing and generative metaprogramming. Static typing eliminates run-time type information by checking safety at compile-time and minimises dynamic checks. Meta-programming uses a single specification to abstract the lowlevel code required to transmit and receive packets. Our domain-specific language, MPL, describes Internet packet protocols and compiles into fast, zero-copy code for both parsing and creating these packets. MPL is designed for implementing quirky Internet protocols ranging from the low-level: Ethernet, IPv4, ICMP and TCP; to the complex application-level: SSH, DNS and BGP; and even file-system protocols such as 9P. We report on fully-featured SSH and DNS servers constructed using MPL and our OCaml framework MELANGE, and measure greater throughput, lower latency, better flexibility and more succinct source code than their C equivalents OpenSSH and BIND. Our quantitative analysis shows that the benefits of MPL-generated code overcomes the additional overheads of automatic garbage collection and dynamic bounds checking. Qualitatively, the flexibility of our approach shows that dramatic optimisations are easily possible. 1