Shining Light On Shadow Stacks

Control-Flow Hijacking attacks are the dominant attack vector against C/C++ programs. Control-Flow Integrity (CFI) solutions mitigate these attacks on the forward edge,i.e., indirect calls through function pointers and virtual calls. Protecting the backward edge is left to stack canaries, which are easily bypassed through information leaks. Shadow Stacks are a fully precise mechanism for protecting backwards edges, and should be deployed with CFI mitigations. We present a comprehensive analysis of all possible shadow stack mechanisms along three axes: performance, compatibility, and security. For performance comparisons we use SPEC CPU2006, while security and compatibility are qualitatively analyzed. Based on our study, we renew calls for a shadow stack design that leverages a dedicated register, resulting in low performance overhead, and minimal memory overhead, but sacrifices compatibility. We present case studies of our implementation of such a design, Shadesmar, on Phoronix and Apache to demonstrate the feasibility of dedicating a general purpose register to a security monitor on modern architectures, and the deployability of Shadesmar. Our comprehensive analysis, including detailed case studies for our novel design, allows compiler designers and practitioners to select the correct shadow stack design for different usage scenarios.Comment: To Appear in IEEE Security and Privacy 201

Hazardous Weather and Human Response in the Southeastern United States

Effectively mitigating the human costs of future hazardous weather events requires examining meteorological threats, their long-term patterns, and human response to these events. The southeastern United States is a region that has both a high climatological risk and a high societal vulnerability to many different meteorological hazards. In this dissertation, I study hazardous weather and human response in the Southeast through three different lenses: identifying uniquely simultaneous hazards posed by tropical cyclones, assessing precipitation and synoptic weather patterns on hazardous weather days, and examining patterns in intended response to tornado watches. I find that simultaneous and collocated tornado and flash flood warnings are common in strong tropical cyclones, particularly those that move slowly after landfall. Additionally, hazardous weather days are common on days dominated by Moist Moderate and Moist Tropical airmasses and airmass transition days. Finally, factors including age, income, self-efficacy beliefs, and knowledge of and experience with tornadoes affect one’s intended response to a tornado watch. These studies produce new contributions to the state of knowledge on both the natural and social elements of hazards studies

DRAFT : Task System and Item Architecture (TSIA)

During its execution, a task is independent of all other tasks. For an application which executes in terms of tasks, the application definition can be free of the details of the execution. Many projects have demonstrated that a task system (TS) can provide such an application with a parallel, distributed, heterogeneous, adaptive, dynamic, real-time, interactive, reliable, secure or other execution. A task consists of items and thus the application is defined in terms of items. An item architecture (IA) can support arrays, routines and other structures of items, thus allowing for a structured application definition. Taking properties from many projects, the support can extend through to currying, application defined types, conditional items, streams and other definition elements. A task system and item architecture (TSIA) thus promises unprecedented levels of support for application execution and definition.Comment: vii+244 pages, including 126 figures of diagrams and code examples. Submitted to Springer Verlag. For further information see http://www.tsia.or

Colossians, cosmology and Christ: A study into Colossians 1:15-17 with insights from Plato's Timaeus, Philo of Alexandria and middle Platonism

Colossians 1:15-20 has often been noted for its distinctive use of language and theological nuance, in particular, its ‘cosmic’ Christology. Pauline and Colossians research have identified Plato’s Timaeus, Middle Platonism and Philo of Alexandria as potentially offering beneficial insight into this Colossian ‘hymn’ and for the letter as a whole. Unfortunately, to date, these identifications have lacked a thorough treatment and have seldom been more than assertions or short, incidental statements that are part of larger projects in Biblical studies. This thesis has undertaken to test and advance the above assertions by providing a clear method and a thorough examination. This thesis has selected Colossians 1:15-17, a notable expression of the author’s Christology and cosmology. The method proposed for examining Colossians 1:15-17 is an analysis of the passage’s terminology and syntactical constructions, and a demonstration of its distinctiveness within the corpus Paulinum. These distinctives are then compared with Platonic texts, primarily Timaeus and the ‘middle platonic’ exposition of Jewish scripture expressed in Philonic corpus. Upon completing the investigation, the selected text was found to be highly distinctive and where these distinctives were indicated, overt lexicographical and conceptual similarities were found with Timaeus and how it was used by Philo of Alexandria. The implications of these findings present similar beneficial insight for the rest of the Colossian hymn (1:18-20) and the wider distinctive language of Colossians

The Impacts Of Lake-Effect Snow On Traffic Volume In Ohio And Indiana, 2011-2015

Snowfall presents a hazard to drivers by reducing visibility and increasing safe stopping distances. As a result, some drivers cancel trips if snowfall is occurring or forecasted, and traffic volumes often decrease on snowy days. Lake-effect snow is very localized and is thus hypothesized to have a lesser influence on traffic volume than synoptic-scale snow, which usually covers a broader areal extent. Traffic volume in northeast Ohio and northern Indiana is studied using a matched-pair analysis to determine if volumes differ between lake-effect and synoptic-scale snowfall in these regions. While little statistical evidence is found to support this hypothesis, other relationships are discovered: lake-effect traffic volume is shown to be dependent in part on distance from the lake and population density of the surrounding area. Other trends relating traffic volume to time-of-day and accident patterns are also explored. Findings presented herein can assist in transportation planning, risk analysis, and roadway safety