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Static Analyzers for Detecting Fatal SW Errors Before Testing 제 3 세부과제

Static Analyzers for Detecting Fatal SW Errors Before Testing 제 3 세부과제. 이광근 교수 Programming Research Lab. Seoul National University 1/16/2007 @ COEX. Content. Technology: Static Program Analysis Prototypes: Airac5, Umirac, Stan Commercialization: Sparrow 1.0. Open Problem.

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Static Analyzers for Detecting Fatal SW Errors Before Testing 제 3 세부과제

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  1. Static Analyzers for Detecting Fatal SW Errors Before Testing제 3 세부과제 이광근 교수 Programming Research Lab.Seoul National University 1/16/2007 @ COEX

  2. Content • Technology: Static Program Analysis • Prototypes: Airac5, Umirac, Stan • Commercialization: Sparrow 1.0

  3. Open Problem • 소프트웨어가 실행되기 전에 • 우리가 바라는대로 실행될 지를 • no core dump/segmentation fault • no buffer overrun • no memory leak • “x.s > 0 at line 321” • “notNull(y) whenever x = 0” • etc. • 엄밀하게 미리 확인해주는 기술은?

  4. Static Program Analysis 프로그램의 실행 내용을 실행전에 자동으로 안전하게 어림잡는 일반적인 기술 “static analysis” “정적분석” “프로그램분석”

  5. 테스트와 다른점 • 테스트는 SW 를 실행시킬 수 있을 때 까지 기다려야 • 테스트는 찾고자 하는 오류를 모두 찾을 수 없음 • 프로그램 분석기(static program analyzer)는 • SW를 실행시키지 않고 타겟 오류의 위치를 자동으로 찾아줌 • SW의 소스만 준비되면 됨

  6. Limitation: 허위 경보(false alarm) • inevitable • repeat if E then x = x+1 else x = x-1 until B • rule of the game • minimize false alarms • no (few) undetected errors • with a reasonable cost errors

  7. Airac5 (Sparrow) • Statically Detecting Buffer-Overrun Errors in C Programs int *c = (int *)malloc(sizeof(int)*10); c[i] = 1; c[i + f()] = 1; c[*k + (*g)()] = 1; x = c+5; x[1] = 1; z->a = c; (z->a)[i] = 1; foo(c+2); int foo(int *d) {… d[i] = 1; …}

  8. Sparrow 성능 Buffer Overrun On a Linux 2.6 box with Pentium4 3.2GHz, 4GB RAM

  9. Umirac • Statically Detecting Unused Memory Areas in C Programs void sigandsets(sigset_t *r, const sigset_t *a, const sigset_t *b) { unsigned long a0, a1, a2, a3, b0, b1, b2, b3; switch ((64 / 32)){ case 4: a3 = a->sig[3]; a2 = a->sig[2]; b3 = b->sig[3]; b2 = b->sig[2]; r->sig[3] = ((a3) & (b3)); r->sig[2] = ((a2) & (b2)); case 2: a1 = a->sig[1]; b1 = b->sig[1]; r->sig[1] = ((a1) & (b1)); case 1: a0 = a->sig[0]; b0 = b->sig[0]; r->sig[0] = ((a0) & (b0)); break; default: _NSIG_WORDS_is_unsupported_size(); } } Linux-2.6.4/include/asm/signal.h:22:1 Target buffer size: {[4,4]}, Unused intervals: {[2,3]} 22: typedef struct {unsigned long sig[4];} sigset_t;

  10. Umirac 성능 UV: unused variables UF: unused fields BB: buffer bubble

  11. Stan • Statically Estimating Stack Size Increment for Each Call Edge main 8 16 simulate 4 setup transduce 82 20 32 12 16 16 compile reset prepare 168 backtrace

  12. Stan 성능 • 함수 포인터 분석 후 call graph 생성 • call 마다 최대 스택 사용량 분석 X264 분석 결과:

  13. Come Visit Our Booth • Demo: Umirac, Stan • Product Demo: Sparrow 1.0 • Talk to us and our sales reps 감사합니다 Programming Research Laboratory Seoul National University

  14. Sparrow 1.0

  15. SW오류 검증 기술의 진화 정적분석기술 효용 및 성숙도 coverity.com polyspace.com Sparrow 1.0 테스트기술 1980s 2000s 2010s 1990s

  16. Sparrow 1.0 • 타겟 소스언어 • C, C++ • ANSI C, GNU C, G++, MS C/C++, ARM C, etc. • 타겟 오류 • buffer overrun • memory leak • uninitialized access • null dereference

  17. Other Players • coverity.com • Stanford U., 미국시장에서 활발, ’05 국내 진출시도 • polyspace.com • Ecole Polytech., 유럽시장에서 활발, ’06 국내 진출시도 • grammatech.com • U. of Wisconsin-Madison, 미국정부시장 • 기타 (분석기술 미흡: “shallow” analysis) • fortify, klocwork, secure, seque, wily • 기존의 runtime tools • 상용 • PurifyPlus, Parasoft Insure++, Trace32, WinDBG, … • 공개SW • Valgrind …

  18. Sparrow 성능 1/2 Buffer Overrun On a Linux 2.6 box with Pentium4 3.2GHz, 4GB RAM

  19. Sparrow 성능 2/2 Memory Leaks On a Linux 2.6 box with Pentium4 3.2GHz, 4GB RAM

  20. Sparrow beats Prevent for True Buffer Overrun 11 • deep call chain • function pointers • function argument • loop induction variables • C standard library – memcpy, memset, … 20 False 36

  21. Sparrow beats Prevent for Memory Leaks • arbitrary pointer aliasing • alloc/free complex data structure • linking argument pointers • infinite loop • recursion 12 True 3 7 2 16 False

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