Laborpruefung/break_server.sh

#!/bin/bash

# ============================================================
# PRACTICE EXAM - BREAK SERVER SCRIPT
# Betriebssysteme und Netzwerke - 45 Minute Practice Test
# ============================================================
# This script intentionally introduces problems for students
# to diagnose and fix during the practice exam
# ============================================================

# Colors for output
RED='\033[0;31m'
GREEN='\033[0;32m'
YELLOW='\033[1;33m'
BLUE='\033[0;34m'
CYAN='\033[0;36m'
MAGENTA='\033[0;35m'
NC='\033[0m' # No Color

print_status() {
    echo -e "${BLUE}[*]${NC} $1"
}

print_success() {
    echo -e "${GREEN}[✓]${NC} $1"
}

print_warning() {
    echo -e "${YELLOW}[!]${NC} $1"
}

print_error() {
    echo -e "${RED}[✗]${NC} $1"
}

print_break() {
    echo -e "${MAGENTA}[BREAK]${NC} $1"
}

# Check if running as root
if [[ $EUID -ne 0 ]]; then
    print_error "This script must be run as root (use sudo)"
    exit 1
fi

# Detect PHP version
PHP_VERSION=$(php -r "echo PHP_MAJOR_VERSION.'.'.PHP_MINOR_VERSION;" 2>/dev/null || echo "8.3")

# ============================================================
# PROBLEM 1: Nginx Configuration Error (company.local)
# Category: Web Server Configuration
# ============================================================
break_nginx_config() {
    print_break "Breaking company.local (Nginx config error)..."

    # Introduce a syntax error - remove semicolon
    cat > /etc/nginx/sites-available/company.local << 'EOF'
server {
    listen 80;
    server_name company.local;

    root /var/www/company;
    index index.html

    location / {
        try_files $uri $uri/ =404;
    }

    error_log /var/log/nginx/company_error.log;
    access_log /var/log/nginx/company_access.log;
}
EOF

    # Try to reload nginx (will fail silently)
    nginx -t > /dev/null 2>&1 || true
    systemctl reload nginx 2>/dev/null || systemctl restart nginx 2>/dev/null || true

    print_success "Problem 1 active: company.local has a configuration error"
}

# ============================================================
# PROBLEM 2: File Permissions (shop.local)
# Category: File System Permissions
# ============================================================
break_file_permissions() {
    print_break "Breaking shop.local (wrong file permissions)..."

    # Remove all permissions from the website directory
    chmod 000 /var/www/shop/index.html

    print_success "Problem 2 active: shop.local has permission issues"
}

# ============================================================
# PROBLEM 3: PHP-FPM Service Stopped (api.local)
# Category: Service Management (systemd)
# ============================================================
break_php_service() {
    print_break "Breaking api.local (PHP-FPM service stopped)..."

    # Stop and disable PHP-FPM
    systemctl stop php${PHP_VERSION}-fpm
    systemctl disable php${PHP_VERSION}-fpm 2>/dev/null

    print_success "Problem 3 active: API returns 502 Bad Gateway (PHP-FPM stopped)"
}

# ============================================================
# PROBLEM 4: Firewall Blocking Docker App
# Category: Firewall (UFW)
# ============================================================
break_firewall() {
    print_break "Breaking Docker app access (firewall block)..."

    # Block port 8888
    ufw delete allow 8888/tcp > /dev/null 2>&1
    ufw deny 8888/tcp > /dev/null 2>&1

    print_success "Problem 4 active: Docker app unreachable (port blocked)"
}

# ============================================================
# PROBLEM 5: MySQL User Configuration
# Category: Database Administration
# ============================================================
break_mysql_user() {
    print_break "Breaking MySQL database access..."

    # Drop the working user and create one bound to wrong IP
    mysql -e "DROP USER IF EXISTS 'webuser'@'localhost';"
    mysql -e "CREATE USER 'webuser'@'10.0.0.1' IDENTIFIED BY 'WebPass123!';"
    mysql -e "GRANT ALL PRIVILEGES ON practicedb.* TO 'webuser'@'10.0.0.1';"
    mysql -e "FLUSH PRIVILEGES;"

    print_success "Problem 5 active: MySQL connection refused (wrong host binding)"
}

# ============================================================
# RESET FUNCTIONS
# ============================================================
reset_nginx_config() {
    print_status "Resetting company.local configuration..."

    cat > /etc/nginx/sites-available/company.local << 'EOF'
server {
    listen 80;
    server_name company.local;

    root /var/www/company;
    index index.html;

    location / {
        try_files $uri $uri/ =404;
    }

    error_log /var/log/nginx/company_error.log;
    access_log /var/log/nginx/company_access.log;
}
EOF

    nginx -t > /dev/null 2>&1 && systemctl reload nginx
    print_success "company.local restored"
}

reset_file_permissions() {
    print_status "Resetting shop.local permissions..."

    chmod 644 /var/www/shop/index.html
    chown www-data:www-data /var/www/shop/index.html

    print_success "shop.local permissions restored"
}

reset_php_service() {
    print_status "Resetting PHP-FPM service..."

    systemctl enable php${PHP_VERSION}-fpm
    systemctl start php${PHP_VERSION}-fpm

    print_success "PHP-FPM service restored"
}

reset_firewall() {
    print_status "Resetting firewall rules..."

    ufw delete deny 8888/tcp > /dev/null 2>&1
    ufw allow 8888/tcp > /dev/null 2>&1

    print_success "Firewall rules restored"
}

reset_mysql_user() {
    print_status "Resetting MySQL user..."

    mysql -e "DROP USER IF EXISTS 'webuser'@'10.0.0.1';"
    mysql -e "DROP USER IF EXISTS 'webuser'@'localhost';"
    mysql -e "CREATE USER 'webuser'@'localhost' IDENTIFIED BY 'WebPass123!';"
    mysql -e "GRANT ALL PRIVILEGES ON practicedb.* TO 'webuser'@'localhost';"
    mysql -e "FLUSH PRIVILEGES;"

    print_success "MySQL user restored"
}

reset_all() {
    echo ""
    print_status "Resetting all problems..."
    echo ""

    reset_nginx_config
    reset_file_permissions
    reset_php_service
    reset_firewall
    reset_mysql_user

    # Restart services
    systemctl restart nginx

    echo ""
    print_success "All problems have been reset!"
    echo ""
}

# ============================================================
# START EXAM (ALL PROBLEMS)
# ============================================================
start_exam() {
    echo ""
    echo -e "${RED}============================================================${NC}"
    echo -e "${RED}         STARTING PRACTICE EXAM - 45 MINUTES${NC}"
    echo -e "${RED}============================================================${NC}"
    echo ""

    print_warning "Introducing 5 problems to the server..."
    echo ""

    break_nginx_config
    break_file_permissions
    break_php_service
    break_firewall
    break_mysql_user

    # Restart nginx to apply changes
    systemctl restart nginx 2>/dev/null || true

    echo ""
    echo -e "${RED}============================================================${NC}"
    echo ""
    print_warning "EXAM STARTED! You have 45 minutes to fix all issues."
    echo ""
    echo "The following services should be working when you're done:"
    echo ""
    echo "  Task 1: http://company.local        - Company Portal"
    echo "  Task 2: http://shop.local           - Online Shop"
    echo "  Task 3: http://api.local:8080       - REST API"
    echo "  Task 4: http://localhost:8888       - Docker App"
    echo "  Task 5: mysql -u webuser -p'WebPass123!' practicedb"
    echo ""
    echo "Use './verify.sh' to check your progress"
    echo ""
    echo -e "${RED}============================================================${NC}"
    echo ""
}

# ============================================================
# VERIFICATION
# ============================================================
verify_all() {
    echo ""
    echo "============================================================"
    echo "             VERIFICATION RESULTS"
    echo "============================================================"
    echo ""

    PASSED=0
    FAILED=0

    # Test company.local
    echo -n "Task 1 - company.local:        "
    if curl -s -o /dev/null -w "%{http_code}" http://company.local 2>/dev/null | grep -q "200"; then
        echo -e "${GREEN}PASS${NC}"
        ((PASSED++))
    else
        echo -e "${RED}FAIL${NC}"
        ((FAILED++))
    fi

    # Test shop.local
    echo -n "Task 2 - shop.local:           "
    if curl -s http://shop.local 2>/dev/null | grep -q "Online Shop"; then
        echo -e "${GREEN}PASS${NC}"
        ((PASSED++))
    else
        echo -e "${RED}FAIL${NC}"
        ((FAILED++))
    fi

    # Test API
    echo -n "Task 3 - api.local:8080:       "
    if curl -s http://api.local:8080 2>/dev/null | grep -q "success"; then
        echo -e "${GREEN}PASS${NC}"
        ((PASSED++))
    else
        echo -e "${RED}FAIL${NC}"
        ((FAILED++))
    fi

    # Test Docker app
    echo -n "Task 4 - Docker app :8888:     "
    if curl -s http://localhost:8888 2>/dev/null | grep -q "Docker"; then
        echo -e "${GREEN}PASS${NC}"
        ((PASSED++))
    else
        echo -e "${RED}FAIL${NC}"
        ((FAILED++))
    fi

    # Test MySQL
    echo -n "Task 5 - MySQL connection:     "
    if mysql -u webuser -p'WebPass123!' practicedb -e "SELECT 1;" > /dev/null 2>&1; then
        echo -e "${GREEN}PASS${NC}"
        ((PASSED++))
    else
        echo -e "${RED}FAIL${NC}"
        ((FAILED++))
    fi

    echo ""
    echo "============================================================"
    echo ""
    echo -e "Results: ${GREEN}${PASSED} PASSED${NC} | ${RED}${FAILED} FAILED${NC}"
    echo ""

    if [ $FAILED -eq 0 ]; then
        echo -e "${GREEN}Congratulations! All tasks completed successfully!${NC}"
    else
        echo -e "${YELLOW}Keep working - ${FAILED} task(s) still need to be fixed.${NC}"
    fi
    echo ""
    echo "============================================================"
}

# ============================================================
# MAIN MENU
# ============================================================
show_menu() {
    clear
    echo ""
    echo -e "${CYAN}============================================================${NC}"
    echo -e "${CYAN}     PRACTICE EXAM - BREAK SERVER MENU${NC}"
    echo -e "${CYAN}     Betriebssysteme und Netzwerke${NC}"
    echo -e "${CYAN}============================================================${NC}"
    echo ""
    echo "  INDIVIDUAL PROBLEMS:"
    echo ""
    echo "    1) Break company.local    (Nginx config error)"
    echo "    2) Break shop.local       (File permissions)"
    echo "    3) Break api.local        (PHP-FPM service)"
    echo "    4) Break Docker app       (Firewall block)"
    echo "    5) Break MySQL            (User configuration)"
    echo ""
    echo "  EXAM MODE:"
    echo ""
    echo "    6) START EXAM (All 5 problems - 45 minutes)"
    echo ""
    echo "  UTILITIES:"
    echo ""
    echo "    7) Verify all services"
    echo "    8) RESET all problems"
    echo "    9) Reset specific problem"
    echo ""
    echo "    0) Exit"
    echo ""
    echo -e "${CYAN}============================================================${NC}"
    echo ""
}

show_reset_menu() {
    echo ""
    echo "  SELECT PROBLEM TO RESET:"
    echo ""
    echo "    1) Reset company.local"
    echo "    2) Reset shop.local"
    echo "    3) Reset api.local (PHP-FPM)"
    echo "    4) Reset Docker app (Firewall)"
    echo "    5) Reset MySQL user"
    echo "    6) Back to main menu"
    echo ""
}

# ============================================================
# MAIN LOOP
# ============================================================
while true; do
    show_menu
    read -p "  Select option: " choice

    case $choice in
        1)
            break_nginx_config
            systemctl restart nginx 2>/dev/null || true
            read -p "Press Enter to continue..."
            ;;
        2)
            break_file_permissions
            read -p "Press Enter to continue..."
            ;;
        3)
            break_php_service
            read -p "Press Enter to continue..."
            ;;
        4)
            break_firewall
            read -p "Press Enter to continue..."
            ;;
        5)
            break_mysql_user
            read -p "Press Enter to continue..."
            ;;
        6)
            start_exam
            read -p "Press Enter to continue..."
            ;;
        7)
            verify_all
            read -p "Press Enter to continue..."
            ;;
        8)
            reset_all
            read -p "Press Enter to continue..."
            ;;
        9)
            show_reset_menu
            read -p "  Select problem to reset: " reset_choice
            case $reset_choice in
                1) reset_nginx_config ;;
                2) reset_file_permissions ;;
                3) reset_php_service ;;
                4) reset_firewall ;;
                5) reset_mysql_user ;;
                6) continue ;;
                *) print_error "Invalid option" ;;
            esac
            read -p "Press Enter to continue..."
            ;;
        0)
            echo ""
            print_status "Goodbye!"
            exit 0
            ;;
        *)
            print_error "Invalid option"
            read -p "Press Enter to continue..."
            ;;
    esac
done