Buffer Overflow

memory

stack smashing detected

Description

The program writes data beyond the end of a buffer, which can overwrite adjacent memory and lead to security vulnerabilities.

Common Causes

• Writing more data to an array than it can hold
• Using unsafe functions like gets, strcpy without bounds checking
• Off-by-one errors in loops

Example of Error

Error Code

int main() {
    char buffer[10];
    strcpy(buffer, "This string is too long for the buffer");
    return 0;
}

Solution

Use bounds-checking functions and ensure array accesses are within bounds.

Corrected Code

int main() {
    char buffer[10];
    strncpy(buffer, "This string is too long", 9);
    buffer[9] = '\0';  // Ensure null termination
    return 0;
}

Additional Tips

• Use strncpy, strncat instead of strcpy, strcat
• Never use gets; use fgets instead
• Always check buffer sizes before writing to them
• Consider using safer alternatives like snprintf
• Use tools like AddressSanitizer to detect buffer overflows