StackGuard is a tool for detecting buffer overflows. It modifies the compiler to place a known (pseudo)random number (a canary) on the stack just before the return address when a function is called. Additional code is added so that, just before the function returns, it pops the canary and compares it to the value that was placed upon the stack. If the two differ, StackGuard asserts a buffer overflow has occurred, and invokes an error handler to terminate the program. How effective is this approach at stopping stack-based buffer overflows? Under what conditions might it fail?

StackGuard is a tool for detecting buffer overflows. It modifies the compiler to place a known (pseudo)random number (a canary) on the stack just before the return address when a function is called. Additional code is added so that, just before the function returns, it pops the canary and compares it to the value that was placed upon the stack. If the two differ, StackGuard asserts a buffer overflow has occurred, and invokes an error handler to terminate the program. How effective is this approach at stopping stack-based buffer overflows? Under what conditions might it fail?

Database System Concepts

7th Edition

ISBN:9780078022159

Author:Abraham Silberschatz Professor, Henry F. Korth, S. Sudarshan

Publisher:Abraham Silberschatz Professor, Henry F. Korth, S. Sudarshan

Chapter1: Introduction

Section: Chapter Questions

Problem 1PE

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StackGuard is a tool for detecting buffer overflows. It modifies the compiler to place a known(pseudo)random number (a canary) on the stack just before the return address when a function is called. Additional code is added so that, just before the function returns, it pops the canary and compares it to the value thatwas placed upon the stack. If the two differ, StackGuard asserts a buffer overflow has occurred, and invokes anerror handler to terminate the program. How effective is this approach at stopping stack-based buffer overflows?Under what conditions might it fail?
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