DARPA Site Visit, Feb 22nd 2012

Scalable RADAR

Jed CrandallStephanie Forrest

Melanie MosesWestley Weimer

DARPA Site Visit, Feb 22nd 2012

Clean Slate• Even with clean-slate designs, change is

inevitable– System requirements– New threats– New technologies and applications

• Focus on robust, adaptive, decentralized responses

• Take biology seriously

DARPA Site Visit, Feb 22nd 2012

Project Overview• Evolutionary program repair

– GenProg: Random variation, selection, inheritance

• Dynamic information flow tracking– Estimate similarity of program behavior on same

input• Simulate RADAR principles

– How does immune system avoid size constraints?

DARPA Site Visit, Feb 22nd 2012

Crosscutting Themes

• Distributed search– Simulations, robots– Distributing the program repair

task

• Measuring and using diversity– Mutational robustness and

proactive diversity– DIFT– Tradeoffs between optimization

and diversity

• Integration– DIFT and GenProg– GenProg on robots?– Other DARPA teams– Beyond DARPA

• Software engineering– Automatic detection of program

invariants– Repair quality---not DARPA

funded!

DARPA Site Visit, Feb 22nd 2012

What’s New?• GenProg repair benchmarks (LeGoues)• Distributed GA results (Schulte, Holtschulte)• DIFT refactoring (Espinoza)• Dynamic invariants (Nguyen)

– Nested array relations– Polynomial time algorithm for array invariants

• ScaleBOTs (Moses)• Mutational robustness

– In progress

DARPA Site Visit, Feb 22nd 2012

Biological Design Principles• Immune system response and times

are scale (size) invariant (Banerjee, dissertation)– Several models fit to (WNV) data

• Lymph nodes architecture + inflammatory signals (ABM and ODE models fit to data)– T-cell search times to scale sub-linearly

with body size • Argentine ants with multiple nests

(ABM)– Distributed foraging algorithm

implemented on 6 robots

Dynamic Invariant Generator (DIG)ThahnVu Nguyen (ICSE ‘12 – Distinguished Paper Award)

• Generate polynomial and array program invariants from execution traces automatically (not from templates)

• Complex invariants– Nonlinear relations among numerical variables, e.g. x = y3a + a, r <=

ya– Relations among multi-dim arrays and functions, e.g. A[i][ = 7B[i] +

8C[i+3] + 5, R[i] = A[B[2i]])

• Ideas/tools from several mathematical domains (e.g., theorem proving)

Recent Developments (submitted to TOSEM ’12)Polynomial Invariants: • Use geometric reasoning to represent different invariant forms (interval,

octagonal, polyhedral)• Prove several interesting properties guaranteed by DIG, but not by template-

based analyses (Daikon)– DIG never overapproximates the real invariants– With sufficient traces, can guarantee that the exact invariant is found

Array Invariants:• Support certain conditional invariants

– e.g. i=even => A[i] = B[i] + C[i]

• Polynomial time algorithm for finding nested array relations• Examples of real invs in AES generated by DIG1 rotWord R[i]=[W[1], W[2], W[3], W[0]]

2 block2State R[i][j] = T[4i + j]

3 subBytes R[i][j]= S[T[i][j]]

4 multWord R[i] = C[(L[A[i]] + L[B[i]]) % 255]

…

DARPA Site Visit, Feb 22nd 2012

Finances

DARPA Site Visit, Feb 22nd 2012

Recent Publications• E. Schulte, J. DiLorenzo, W. Weimer, S. Forrest “Automated repair of binary and assembly

programs for cooperating embedded devices” ASPLOS, to appear.• R. Buse, W. Weimer “Synthesizing API Usage Examples” ICSE 2012.• C. Le Goues, M. Dewey-Vogt, S. Forrest, and W. Weimer "A systematic study of automated

program repair: Fixing 55 out of 105 bugs for $8.00 each" ICSE 2012.• T. Nguyen, D. Kapur, W. Weimer, and S. Forrest ``Using Dynamic Analysis to Discover

Polynomial and Array Invariants" ICSE 2012. ACM SIGSOFT Distinguished Paper Award.• C. Le Goues, W. Weimer, S. Forrest “Representations and operators for Improving

Evolutionary Software Repair” GECCO 2012.Nominated for best paper.• J. Knockel and J. Crandall “ Protecting Free and Open Communications on the Internet

Against Man-in-the-Middle Attacks on Third-Party Software: We're FOCI’d” FOCI 2012 • N. Aase, J. Crandall, et al. “Whiskey, weed, and Wukan on the World Wide Web: On

measuring censors’ resources and motivations. FOCI 2012• D. Oliveira and J. Crandall. Holographic vulnerability studies: Vulnerabilities as fractures in

interpretation as information flows across abstraction boundaries. NSPW 201. (also presented at ACSAC 2012 NSPW experience panel).

DARPA Site Visit, Feb 22nd 2012

Recent Publications cont.• Hecker, J. P., K. Letendre, K. Stolleis, D. Washington and M. E. Moses. (2012).

"Formica ex Machina: Ant Swarm Foraging From Physical to Virtual and Back Again." Proceedings of the Eighth International Conference on Swarm Intelligence, Brussels in Lecture Notes in Computer Science: 7461.

• Moses, M. E., K. Letendre, T. P. Flanagan and J. P. Hecker. (2012) "In vivo, in silico, in machina}: Ants balance memory and communication to collectively exploit information." Proceedings of the 2012 European Conference on Complex Systems (in press, Lecture Notes in Computer Science as a non peer reviewed workshop paper).

• Holtschulte, N. J. and M. E. Moses. (2012) "Diversity and Resistance in a Model Network with Adaptive Software." Security Informatics 1:19, Biologically Inspired Approaches Special Issue.

• Moses, M. E. and S. Forrest. (2012) "Beyond Biology" in Metabolic Ecology: A Scaling Approach. Eds. R.M. Sibly, A. Kodric-Brown and J.H. Brown. Wiley-Blackwell. 293-301.

DARPA Site Visit, Feb 22nd 2012

Submitted Publications• C. Le Goues, S. Forrest, W. Weimer “Current challenges in automatic software

repair” Software Quality Journal, submitted.• T. Nguyen, D. Kapur, W. Weimer, S. Forrest “DIG: A dynamic invariant generator for

polynomial and array invariants” TOSEM, submitted.• E. Schulte, Z. Fry, E. Fast, W. Weimer, S. Forrest “Software mutational robustness”

GPEM, submitted.• D. Levin, S. Forrest, S. Banerjee, C. Clay, M. Mitchell, and F. Koster “Spatially explicit

model of the lymphocyte diaspora in influenza-infected lung quantifies constraints of chemokine directed migration PLoS Computational Biology, submitted.

• Letendre, K. and M. E. Moses. "Conflict and synergy in ant foraging strategies: Site fidelity and recruitment alone and in combination." submitted to GECCO 2013.

• Holtshulte, N and M. E. Moses "Should Every Man Be an Island? Island number and population size for popular benchmark functions." submitted to GECCO 2013.

DARPA Site Visit, Feb 22nd 2012

Other Publications(not directly supported by CRASH)

• P. Hooimeijer and W. Weimer “StrSolve: solving string constraints lazily” Autom. Softw. Eng. 19(4): 531-559 (2012)

• Z. Fry, B. Landau, W. Weimer “A Human Study of Patch Maintainability” ISSTA 2012.• C. Le Goues and W. Weimer “Measuring Code Quality to Improve

Specification Mining? IEEE Trans. Software Engineering 38(1): 175-190 (2012)• M. Groat, B. Edwards, J. Horey, W. He, and S. Forrest ``Enhancing privacy in

participatory sensing applications with multidimensional data” PERCOM 2012 • J. Horey, M. Groat, and S. Forrest ``Reconstructing spatial distributions from

anonymized locations’’ ICDE 2012.• M. Groat, B. Edwards, J. Horey, W. He, S. Forrest “Enhancing privacy in

participatory applications with multidimensional data” Pervasive and Mobile Computing, in press.

• B. Edwards, T. Moore, G. Stelle, S. Hofmeyr and S. Forrest. ``Beyond the blacklist: Modeling malware spread and the effect of interventions” NSPW 2012. (also presented at ACSAC 2012 NSPW experience panel).

DARPA Site Visit, Feb 22nd 2012

Plan for Today11:30 Lunch 30 minutes to collect food and review posters

12:00 Stephanie Forrest Welcome and Project Overview (30 min)

12:30 Claire Le Goues/Shirley Park

GenProg, Benchmarks, Scalability and Templates (30 min)

1:00 Zak Fry Improving GenProg Fitness Functions (20 min)

1:20 Jonathan Dorn Lifting the Test Case Assumption (20 min)

1:40 Break

1:50 Eric Schulte Repairing ASM/ELF programs with Island GA (20 min)

2:10 Claire Le Goues Phone Twitter Repair Demo (10 min)

2:20 Neal Holtschulte Improving Island GAs (20 min)

2:40 Antonio Espinoza DIFT and GenProg Integration (20 min)

3:00 Adam Brady Evolving More Efficient Graphics Programs (20 min)

3:20 Break

3:30 Westley Weimer Discussion, Integration, Next Steps

4:00 Final Discussion, Review Posters

4:30 Depart

DARPA Site Visit, Feb 22nd 2012

BACKUP SLIDES

Complexity Results for Finding Array Invs

Simple (non-nested) array relations: • Examples: R[i][j] = T[4i+j], A[i][j] = 7B[i] + 8C[i+j+3] + 5i• Complexity: O(N3), N: # of array elements• Main ideas: flattening arrays (treating arr elems as new vars) and

solving equations

Complex (nested) array relations: • Examples: R[i][j] = S[T[i[j]], A[i][j] = B[C[D[i]][3]][E[i + j + 3]]• Complexity: O(NdV), V: # of arrays, N: # of array elements, d:

highest dim among arrays– By fixing d,V (in practice, these params are small), complexity is in class P

wrt to N– NP-Complete wrt to V (reduction from Set Covering prob)

• Main ideas: use reachability analysis to enumerate nesting rels among array indices and solving equations

DARPA Site Visit, Feb 22nd 2012

Scalable RADAR: Approach

• Evolution• Diversity• Allometry

Take Biology Seriously

INPUT

OUTPUT

EVALUATE FITNESS

MUTATE

DISCARD

ACCEPT

DARPA Site Visit, Feb 22nd 2012

Schedule and Milestones