#!/bin/bash
#
# setup_host.sh - Prepare host system for covert channel testing
#
# Run this BEFORE docker-compose up
#

set -e

echo "╔════════════════════════════════════════════════════════════════╗"
echo "║  Host Setup for CVE-2023-1206 + CVE-2024-49882 Covert Channel  ║"
echo "╚════════════════════════════════════════════════════════════════╝"
echo

# Check if running as root
if [ "$EUID" -ne 0 ]; then
    echo "[!] Please run as root: sudo $0"
    exit 1
fi

# 1. Check kernel version
echo "[*] Checking kernel version..."
KERNEL=$(uname -r)
echo "    Current kernel: $KERNEL"

if [[ "$KERNEL" != *"6.12"* ]]; then
    echo "[!] Warning: Expected kernel 6.12.x with vulnerability"
    echo "    You may need to boot into the vulnerable kernel"
fi

# 2. Setup hugepages
echo
echo "[*] Setting up hugepages..."

CURRENT_HP=$(cat /sys/kernel/mm/hugepages/hugepages-2048kB/nr_hugepages)
echo "    Current hugepages: $CURRENT_HP"

if [ "$CURRENT_HP" -lt 128 ]; then
    echo "    Allocating 256 hugepages..."
    
    # Drop caches first
    sync
    echo 3 > /proc/sys/vm/drop_caches
    
    echo 256 > /sys/kernel/mm/hugepages/hugepages-2048kB/nr_hugepages
    
    NEW_HP=$(cat /sys/kernel/mm/hugepages/hugepages-2048kB/nr_hugepages)
    FREE_HP=$(cat /sys/kernel/mm/hugepages/hugepages-2048kB/free_hugepages)
    echo "    Allocated: $NEW_HP, Free: $FREE_HP"
else
    echo "    Hugepages already configured"
fi

# 3. Load udmabuf module
echo
echo "[*] Loading udmabuf module..."

if lsmod | grep -q udmabuf; then
    echo "    udmabuf already loaded"
else
    modprobe udmabuf
    echo "    udmabuf loaded"
fi

# Check /dev/udmabuf
if [ -e /dev/udmabuf ]; then
    echo "    /dev/udmabuf exists"
    chmod 666 /dev/udmabuf
else
    echo "[!] /dev/udmabuf not found!"
    echo "    Creating device node..."
    MINOR=$(cat /proc/misc | grep udmabuf | awk '{print $1}')
    if [ -n "$MINOR" ]; then
        mknod /dev/udmabuf c 10 $MINOR
        chmod 666 /dev/udmabuf
    else
        echo "[!] Failed to create /dev/udmabuf"
    fi
fi

# 4. Enable IPv6
echo
echo "[*] Configuring IPv6..."

sysctl -w net.ipv6.conf.all.forwarding=1 >/dev/null
sysctl -w net.ipv6.conf.default.forwarding=1 >/dev/null
echo "    IPv6 forwarding enabled"

# 5. Docker configuration
echo
echo "[*] Checking Docker IPv6 configuration..."

if [ -f /etc/docker/daemon.json ]; then
    if grep -q "ipv6" /etc/docker/daemon.json; then
        echo "    Docker IPv6 already configured"
    else
        echo "[!] Docker IPv6 not configured"
        echo "    Add to /etc/docker/daemon.json:"
        echo '    {"ipv6": true, "fixed-cidr-v6": "fd00::/80"}'
    fi
else
    echo "    Creating Docker daemon.json..."
    cat > /etc/docker/daemon.json << 'EOF'
{
  "ipv6": true,
  "fixed-cidr-v6": "fd00::/80",
  "experimental": true,
  "ip6tables": true
}
EOF
    echo "    Restarting Docker..."
    systemctl restart docker
fi

# 6. Create hugepages mount if needed
echo
echo "[*] Checking hugepages mount..."

if mountpoint -q /dev/hugepages; then
    echo "    /dev/hugepages is mounted"
else
    echo "    Mounting hugetlbfs..."
    mkdir -p /dev/hugepages
    mount -t hugetlbfs nodev /dev/hugepages
fi

chmod 1777 /dev/hugepages

# 7. Summary
echo
echo "╔════════════════════════════════════════════════════════════════╗"
echo "║  Setup Complete!                                                ║"
echo "╠════════════════════════════════════════════════════════════════╣"
echo "║                                                                 ║"
printf "║  Kernel:     %-50s  ║\n" "$KERNEL"
printf "║  Hugepages:  %-50s  ║\n" "$(cat /sys/kernel/mm/hugepages/hugepages-2048kB/free_hugepages) free"
printf "║  udmabuf:    %-50s  ║\n" "$(ls -la /dev/udmabuf 2>/dev/null | awk '{print $1}' || echo 'NOT FOUND')"
echo "║                                                                 ║"
echo "║  Next steps:                                                    ║"
echo "║    1. cd ~/covert_channel                                       ║"
echo "║    2. docker-compose build                                      ║"
echo "║    3. docker-compose up victim_db                               ║"
echo "║    4. docker-compose run --rm attacker                          ║"
echo "║                                                                 ║"
echo "╚════════════════════════════════════════════════════════════════╝"