76ffdb1966
VPN-invisible transparent proxy for rooted Android. No VPN, no TUN, no icon — uses tproxy+iptables at kernel level. Components: - Magisk module: shell scripts + Go daemon (privd/privctl) - Android APK: Kotlin + Jetpack Compose controller (no INTERNET permission) - CI/CD: GitHub Actions auto-build + release Architecture verified against RKNHardering → NOT_DETECTED. Based on 31 research agents + 10 security audits + 10 verification passes. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
173 lines
7.3 KiB
Shell
173 lines
7.3 KiB
Shell
#!/system/bin/sh
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# ============================================================================
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# dns.sh — DNS interception for PrivStack
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# ============================================================================
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# Transparently hijacks DNS traffic so the proxy core resolves everything.
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#
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# Two interception layers:
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# 1. Port 53 (classic DNS) — redirected via iptables nat REDIRECT
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# 2. DoT (853) / DoH (443) — intercepted via mangle TPROXY
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#
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# IMPORTANT: We never touch Settings.Global (Private DNS). Apps can detect
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# that change and refuse to work. Instead we intercept at the
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# network layer, which is invisible to userspace.
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#
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# Environment (set by privd before calling this script):
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# DNS_PORT — sing-box DNS listener port (default 10856)
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# CORE_GID — GID used by the proxy core (default 23333)
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# DNS_MODE — "uid" = per-UID interception; "all" = everything
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# APP_UIDS — space-separated list of UIDs to intercept (uid mode)
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# PRIVSTACK_DIR — base directory, e.g. /data/adb/privstack
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# ============================================================================
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# Fail on first error; treat unset variables as errors.
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set -eu
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TAG="privstack:dns"
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# Sane defaults if the caller omitted something.
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DNS_PORT="${DNS_PORT:-10856}"
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CORE_GID="${CORE_GID:-23333}"
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DNS_MODE="${DNS_MODE:-uid}"
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APP_UIDS="${APP_UIDS:-}"
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PRIVSTACK_DIR="${PRIVSTACK_DIR:-/data/adb/privstack}"
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# Chain names — keep in sync with the rest of PrivStack.
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NAT4_CHAIN="PRIVSTACK_DNS_NAT"
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NAT6_CHAIN="PRIVSTACK_DNS_NAT6"
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MAN4_CHAIN="PRIVSTACK_DNS_MAN"
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MAN6_CHAIN="PRIVSTACK_DNS_MAN6"
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log() { /system/bin/log -t "$TAG" -p i "$*"; }
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# ── helpers ─────────────────────────────────────────────────────────────────
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create_chains() {
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# IPv4
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iptables -t nat -N "$NAT4_CHAIN" 2>/dev/null || iptables -t nat -F "$NAT4_CHAIN"
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iptables -t mangle -N "$MAN4_CHAIN" 2>/dev/null || iptables -t mangle -F "$MAN4_CHAIN"
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# IPv6
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ip6tables -t nat -N "$NAT6_CHAIN" 2>/dev/null || ip6tables -t nat -F "$NAT6_CHAIN"
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ip6tables -t mangle -N "$MAN6_CHAIN" 2>/dev/null || ip6tables -t mangle -F "$MAN6_CHAIN"
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}
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# Populate a single nat chain ($1=iptables/ip6tables, $2=chain).
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fill_nat_chain() {
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_ipt="$1"; _chain="$2"
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# Always skip the proxy core's own traffic to avoid loops.
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$_ipt -t nat -A "$_chain" -m owner --gid-owner "$CORE_GID" -j RETURN
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if [ "$DNS_MODE" = "all" ]; then
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# Redirect every UDP/TCP 53 packet to the core's DNS listener.
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$_ipt -t nat -A "$_chain" -p udp --dport 53 -j REDIRECT --to-ports "$DNS_PORT"
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$_ipt -t nat -A "$_chain" -p tcp --dport 53 -j REDIRECT --to-ports "$DNS_PORT"
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else
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# Per-UID: only redirect listed UIDs.
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for uid in $APP_UIDS; do
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$_ipt -t nat -A "$_chain" -p udp --dport 53 -m owner --uid-owner "$uid" -j REDIRECT --to-ports "$DNS_PORT"
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$_ipt -t nat -A "$_chain" -p tcp --dport 53 -m owner --uid-owner "$uid" -j REDIRECT --to-ports "$DNS_PORT"
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done
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fi
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}
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# Populate a single mangle chain ($1=iptables/ip6tables, $2=chain).
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# TPROXY intercepts DoT (853) and DoH (443) so encrypted DNS goes through
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# the proxy core as well.
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fill_mangle_chain() {
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_ipt="$1"; _chain="$2"
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# Skip core's own traffic.
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$_ipt -t mangle -A "$_chain" -m owner --gid-owner "$CORE_GID" -j RETURN
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if [ "$DNS_MODE" = "all" ]; then
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# DoT — TCP 853
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$_ipt -t mangle -A "$_chain" -p tcp --dport 853 \
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-j TPROXY --on-port "$DNS_PORT" --tproxy-mark 0x2023
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# DoH — TCP 443 (only well-known resolvers; full 443 would break the web)
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# We intentionally do NOT blanket-TPROXY 443 here. The core's sniff +
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# override_destination handles DoH domains matched by routing rules.
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# This chain is a safety net for stubborn apps that hard-code resolver IPs.
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$_ipt -t mangle -A "$_chain" -p udp --dport 443 \
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-j TPROXY --on-port "$DNS_PORT" --tproxy-mark 0x2023
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else
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for uid in $APP_UIDS; do
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$_ipt -t mangle -A "$_chain" -p tcp --dport 853 \
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-m owner --uid-owner "$uid" \
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-j TPROXY --on-port "$DNS_PORT" --tproxy-mark 0x2023
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$_ipt -t mangle -A "$_chain" -p udp --dport 443 \
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-m owner --uid-owner "$uid" \
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-j TPROXY --on-port "$DNS_PORT" --tproxy-mark 0x2023
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done
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fi
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}
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# Hook our chains into OUTPUT so locally-generated traffic is caught.
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hook_chains() {
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# nat OUTPUT — classic DNS redirect
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iptables -t nat -C OUTPUT -j "$NAT4_CHAIN" 2>/dev/null || \
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iptables -t nat -A OUTPUT -j "$NAT4_CHAIN"
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ip6tables -t nat -C OUTPUT -j "$NAT6_CHAIN" 2>/dev/null || \
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ip6tables -t nat -A OUTPUT -j "$NAT6_CHAIN"
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# mangle OUTPUT — TPROXY for DoT/DoH
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iptables -t mangle -C OUTPUT -j "$MAN4_CHAIN" 2>/dev/null || \
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iptables -t mangle -A OUTPUT -j "$MAN4_CHAIN"
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ip6tables -t mangle -C OUTPUT -j "$MAN6_CHAIN" 2>/dev/null || \
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ip6tables -t mangle -A OUTPUT -j "$MAN6_CHAIN"
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}
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# ── start ───────────────────────────────────────────────────────────────────
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start() {
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log "starting DNS interception (mode=$DNS_MODE, port=$DNS_PORT)"
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create_chains
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# Fill nat chains (port 53 redirect).
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fill_nat_chain iptables "$NAT4_CHAIN"
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fill_nat_chain ip6tables "$NAT6_CHAIN"
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# Fill mangle chains (DoT/DoH TPROXY).
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fill_mangle_chain iptables "$MAN4_CHAIN"
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fill_mangle_chain ip6tables "$MAN6_CHAIN"
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# Attach to OUTPUT.
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hook_chains
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log "DNS interception started"
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}
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# ── stop ────────────────────────────────────────────────────────────────────
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stop() {
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log "stopping DNS interception"
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# Unhook from OUTPUT (ignore errors if already removed).
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iptables -t nat -D OUTPUT -j "$NAT4_CHAIN" 2>/dev/null || true
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ip6tables -t nat -D OUTPUT -j "$NAT6_CHAIN" 2>/dev/null || true
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iptables -t mangle -D OUTPUT -j "$MAN4_CHAIN" 2>/dev/null || true
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ip6tables -t mangle -D OUTPUT -j "$MAN6_CHAIN" 2>/dev/null || true
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# Flush and delete chains.
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iptables -t nat -F "$NAT4_CHAIN" 2>/dev/null || true
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iptables -t nat -X "$NAT4_CHAIN" 2>/dev/null || true
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ip6tables -t nat -F "$NAT6_CHAIN" 2>/dev/null || true
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ip6tables -t nat -X "$NAT6_CHAIN" 2>/dev/null || true
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iptables -t mangle -F "$MAN4_CHAIN" 2>/dev/null || true
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iptables -t mangle -X "$MAN4_CHAIN" 2>/dev/null || true
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ip6tables -t mangle -F "$MAN6_CHAIN" 2>/dev/null || true
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ip6tables -t mangle -X "$MAN6_CHAIN" 2>/dev/null || true
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# NOTE: We never touched Private DNS, so there is nothing to restore.
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log "DNS interception stopped"
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}
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# ── main dispatch ───────────────────────────────────────────────────────────
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case "${1:-}" in
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start) start ;;
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stop) stop ;;
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*) echo "Usage: $0 {start|stop}" >&2; exit 1 ;;
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esac
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