--- src/wg-quick/linux.bash | 170 ++++++++++++++++++++++------------------ 1 file changed, 95 insertions(+), 75 deletions(-)
diff --git a/src/wg-quick/linux.bash b/src/wg-quick/linux.bash index 7c2c002..a157006 100755 --- a/src/wg-quick/linux.bash +++ b/src/wg-quick/linux.bash @@ -26,6 +26,10 @@ CONFIG_FILE="" PROGRAM="${0##*/}" ARGS=( "$@" ) +# needs to match across all wireguard devices, because only one +# suppress_ifgroup is supported +IFGROUP=51820 + cmd() { echo "[#] $*" >&2 "$@" @@ -93,21 +97,17 @@ add_if() { } del_if() { - local table [[ $HAVE_SET_DNS -eq 0 ]] || unset_dns - [[ $HAVE_SET_FIREWALL -eq 0 ]] || remove_firewall - if [[ -z $TABLE || $TABLE == auto ]] && get_fwmark table && [[ $(wg show "$INTERFACE" allowed-ips) =~ /0(\ |$'\n'|$) ]]; then - while [[ $(ip -4 rule show 2>/dev/null) == *"lookup $table"* ]]; do - cmd ip -4 rule delete table $table - done - while [[ $(ip -4 rule show 2>/dev/null) == *"from all lookup main suppress_prefixlength 0"* ]]; do - cmd ip -4 rule delete table main suppress_prefixlength 0 - done - while [[ $(ip -6 rule show 2>/dev/null) == *"lookup $table"* ]]; do - cmd ip -6 rule delete table $table - done - while [[ $(ip -6 rule show 2>/dev/null) == *"from all lookup main suppress_prefixlength 0"* ]]; do - cmd ip -6 rule delete table main suppress_prefixlength 0 + if [[ $TABLE == '' || $TABLE == auto ]]; then + for proto in -4 -6; do + while read prio rule; do + if [[ $rule == *[io]if\ $INTERFACE* || $rule == *"ipproto udp sport $(wg show $INTERFACE listen-port)"* ]]; then + if [[ $rule =~ lookup\ ([^ ]*) ]] && [[ ${BASH_REMATCH[1]} != main ]]; then + cmd ip $proto route flush table ${BASH_REMATCH[1]} + fi + cmd ip $proto rule delete priority ${prio%:} + fi + done < <(ip $proto rule show) done fi cmd ip link delete dev "$INTERFACE" @@ -173,75 +173,87 @@ add_route() { fi } -get_fwmark() { - local fwmark - fwmark="$(wg show "$INTERFACE" fwmark)" || return 1 - [[ -n $fwmark && $fwmark != off ]] || return 1 - printf -v "$1" "%d" "$fwmark" - return 0 -} +allocate_gap() { + # allocate a gap from stdin between min and max inclusive + local var=$1 min=$2 max=$3 + local prev_ent=$((min - 1)) -remove_firewall() { - if type -p nft >/dev/null; then - local table nftcmd - while read -r table; do - [[ $table == *" wg-quick-$INTERFACE" ]] && printf -v nftcmd '%sdelete %s\n' "$nftcmd" "$table" - done < <(nft list tables 2>/dev/null) - [[ -z $nftcmd ]] || cmd nft -f <(echo -n "$nftcmd") - fi - if type -p iptables >/dev/null; then - local line iptables found restore - for iptables in iptables ip6tables; do - restore="" found=0 - while read -r line; do - [[ $line == "*"* || $line == COMMIT || $line == "-A "*"-m comment --comment \"wg-quick(8) rule for $INTERFACE\""* ]] || continue - [[ $line == "-A"* ]] && found=1 - printf -v restore '%s%s\n' "$restore" "${line/#-A/-D}" - done < <($iptables-save 2>/dev/null) - [[ $found -ne 1 ]] || echo -n "$restore" | cmd $iptables-restore -n - done + # find a gap + while read this_ent && (( this_ent <= prev_ent + 1 && this_ent <= max )); do + if (( this_ent >= min )); then + prev_ent=$this_ent + fi + done + + # verify gap + if (( prev_ent + 1 >= min )) && (( prev_ent + 1 <= max )); then + printf -v "$var" "$((prev_ent + 1))" + return 0 + else + return 1 fi } -HAVE_SET_FIREWALL=0 +allocate_table() { + allocate_gap $1 51820 4294967295 \ + < <(ip -N route show table all | sed -n -e 's/.*table \([0-9]*\).*/\1/p' | sort -u) \ + || die 'could not allocate routing table' +} + +allocate_rule() { + allocate_gap "$@" < <({ ip -4 -N rule show; ip -6 -N rule show; } | sed -e 's/:.*//' | sort -u) \ + || die 'could not allocate routing rule' +} + add_default() { - local table line - if ! get_fwmark table; then - table=51820 - while [[ -n $(ip -4 route show table $table 2>/dev/null) || -n $(ip -6 route show table $table 2>/dev/null) ]]; do - ((table++)) - done - cmd wg set "$INTERFACE" fwmark $table - fi - local proto=-4 iptables=iptables pf=ip - [[ $1 == *:* ]] && proto=-6 iptables=ip6tables pf=ip6 + local proto=-4 table rule_main rule_wg + [[ $1 == *:* ]] && proto=-6 + allocate_table table cmd ip $proto route add "$1" dev "$INTERFACE" table $table - cmd ip $proto rule add not fwmark $table table $table - cmd ip $proto rule add table main suppress_prefixlength 0 - - local marker="-m comment --comment \"wg-quick(8) rule for $INTERFACE\"" restore=$'*raw\n' nftable="wg-quick-$INTERFACE" nftcmd - printf -v nftcmd '%sadd table %s %s\n' "$nftcmd" "$pf" "$nftable" - printf -v nftcmd '%sadd chain %s %s preraw { type filter hook prerouting priority -300; }\n' "$nftcmd" "$pf" "$nftable" - printf -v nftcmd '%sadd chain %s %s premangle { type filter hook prerouting priority -150; }\n' "$nftcmd" "$pf" "$nftable" - printf -v nftcmd '%sadd chain %s %s postmangle { type filter hook postrouting priority -150; }\n' "$nftcmd" "$pf" "$nftable" - while read -r line; do - [[ $line =~ .*inet6?\ ([0-9a-f:.]+)/[0-9]+.* ]] || continue - printf -v restore '%s-I PREROUTING ! -i %s -d %s -m addrtype ! --src-type LOCAL -j DROP %s\n' "$restore" "$INTERFACE" "${BASH_REMATCH[1]}" "$marker" - printf -v nftcmd '%sadd rule %s %s preraw iifname != "%s" %s daddr %s fib saddr type != local drop\n' "$nftcmd" "$pf" "$nftable" "$INTERFACE" "$pf" "${BASH_REMATCH[1]}" - done < <(ip -o $proto addr show dev "$INTERFACE" 2>/dev/null) - printf -v restore '%sCOMMIT\n*mangle\n-I POSTROUTING -m mark --mark %d -p udp -j CONNMARK --save-mark %s\n-I PREROUTING -p udp -j CONNMARK --restore-mark %s\nCOMMIT\n' "$restore" $table "$marker" "$marker" - printf -v nftcmd '%sadd rule %s %s postmangle meta l4proto udp mark %d ct mark set mark \n' "$nftcmd" "$pf" "$nftable" $table - printf -v nftcmd '%sadd rule %s %s premangle meta l4proto udp meta mark set ct mark \n' "$nftcmd" "$pf" "$nftable" - [[ $proto == -4 ]] && cmd sysctl -q net.ipv4.conf.all.src_valid_mark=1 - if type -p nft >/dev/null; then - cmd nft -f <(echo -n "$nftcmd") - else - echo -n "$restore" | cmd $iptables-restore -n - fi - HAVE_SET_FIREWALL=1 + allocate_rule rule_main 10000 20000 + cmd ip $proto rule add priority $rule_main not oif $INTERFACE table main suppress_prefixlength 0 + allocate_rule rule_wg 10000 20000 + cmd ip $proto rule add priority $rule_wg not iif lo ipproto udp sport $(wg show $INTERFACE listen-port) lookup $table return 0 } +set_strong_host() { + case "$(ip rule show priority 0)" in + $'0:\tfrom all lookup local') ;; + $'0:\tfrom all lookup local suppress_ifgroup '$IFGROUP) ;; + *) die "strong host rules cannot be applied due to non-default ip rule 0" ;; + esac + case "$(ip rule show priority 1)" in + '') ;; + $'1:\tfrom all iif lo lookup local') ;; + *) die "strong host rules cannot be applied due to non-default ip rule 1" ;; + esac + local table_local table_drop rule_iif rule_drop + + ip link set $INTERFACE group $IFGROUP + # this can be done with ip -batch, but this way allows us to use the cmd wrapper + allocate_table table_local + ip $proto route show table local dev $INTERFACE | while read route; do + cmd ip $proto route add $route dev $INTERFACE table $table_local + done + allocate_table table_drop + ip $proto route show table local dev $INTERFACE | grep '^local' | while read route; do + cmd ip $proto route add blackhole ${route#local} table $table_drop + done + allocate_rule rule_iif 1000 5000 + cmd ip $proto rule add priority $rule_iif iif $INTERFACE lookup $table_local + allocate_rule rule_drop 1000 5000 + cmd ip $proto rule add priority $rule_drop not iif $INTERFACE lookup $table_drop + if [[ $(ip rule show priority 0) == $'0:\tfrom all lookup local' ]]; then + cmd ip $proto rule add lookup local suppress_ifgroup $IFGROUP priority 0 + cmd ip $proto rule del lookup local priority 0 + fi + if [[ $(ip rule show priority 1) == $'0:\tfrom all lookup local' ]]; then + cmd ip $proto rule add iif lo lookup local priority 1 + cmd ip $proto rule del lookup local priority 1 + fi +} + set_config() { cmd wg setconf "$INTERFACE" <(echo "$WG_CONFIG") } @@ -330,11 +342,20 @@ cmd_up() { done set_mtu_up set_dns + if grep -q -E '0|2' /proc/sys/net/ipv4/conf/*/rp_filter; then + rp_filter_is_off=1 + fi + if [[ $TABLE == '' || $TABLE == auto ]] && [[ $rp_filter_is_off == 1 ]]; then + set_strong_host + fi for i in $(while read -r _ i; do for i in $i; do [[ $i =~ ^[0-9a-z:.]+/[0-9]+$ ]] && echo "$i"; done; done < <(wg show "$INTERFACE" allowed-ips) | sort -nr -k 2 -t /); do add_route "$i" done execute_hooks "${POST_UP[@]}" trap - INT TERM EXIT + if [[ $rp_filter_is_off == 1 ]] && grep -q 1 /proc/sys/net/{ipv4,ipv6}/conf/*/forwarding; then + echo "$PROGRAM: warning: ensure rp_filter is installed, see https://www.wireguard.com/rp_filter" >&2 + fi } cmd_down() { @@ -343,7 +364,6 @@ cmd_down() { [[ $SAVE_CONFIG -eq 0 ]] || save_config del_if unset_dns || true - remove_firewall || true execute_hooks "${POST_DOWN[@]}" } -- 2.26.0