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      • C Secure Functions

      Using secure functions to prevent common security vulnerabilities.

      1. String Functions

      // Instead of strcpy
strncpy(dest, src, sizeof(dest) - 1);
dest[sizeof(dest) - 1] = '\0';

// Instead of strcat
strncat(dest, src, sizeof(dest) - strlen(dest) - 1);

// Instead of sprintf
snprintf(buffer, sizeof(buffer), "Value: %d", value);

      2. Input Functions

      // Instead of gets (dangerous)
fgets(buffer, sizeof(buffer), stdin);

// Remove newline if present
buffer[strcspn(buffer, "\n")] = '\0';

      3. Memory Functions

      // Instead of memcpy for overlapping regions
memmove(dest, src, size);

      4. Bounds Checking

      // Always check array bounds
if (index >= 0 && index < array_size) {
    array[index] = value;
}

      5. Integer Overflow

      // Check for overflow
if (a > INT_MAX - b) {
    // Handle overflow
}

      6. Best Practices

      • Use functions with size parameters
      • Validate all inputs
      • Check return values
      • Use compiler security flags