[RFC PATCH] wg-quick/linux: switch to ip rule rp filter
Alex Xu (Hello71)
alex_y_xu at yahoo.ca
Fri Mar 6 18:04:04 CET 2020
---
src/wg-quick/linux.bash | 113 ++++++++++++++++++++--------------------
1 file changed, 56 insertions(+), 57 deletions(-)
diff --git a/src/wg-quick/linux.bash b/src/wg-quick/linux.bash
index 7c2c002..7bd2f85 100755
--- a/src/wg-quick/linux.bash
+++ b/src/wg-quick/linux.bash
@@ -22,10 +22,15 @@ POST_UP=( )
PRE_DOWN=( )
POST_DOWN=( )
SAVE_CONFIG=0
+ALLOWEDIPS=( )
CONFIG_FILE=""
PROGRAM="${0##*/}"
ARGS=( "$@" )
+# needs to match across all wireguard devices, because only one
+# suppress_ifgroup is supported
+IFGROUP=51820
+
cmd() {
echo "[#] $*" >&2
"$@"
@@ -65,6 +70,7 @@ parse_options() {
SaveConfig) read_bool SAVE_CONFIG "$value"; continue ;;
esac
fi
+ [[ $key == "AllowedIPs" ]] && ALLOWEDIPS+=( ${value//,/ } )
WG_CONFIG+="$line"$'\n'
done < "$CONFIG_FILE"
shopt -u nocasematch
@@ -93,21 +99,23 @@ add_if() {
}
del_if() {
- local table
+ local table table_local table_drop
[[ $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 [[ $(ip -6 rule show 2>/dev/null) == *"from all lookup main suppress_prefixlength 0"* ]]; do
- cmd ip -6 rule delete table main suppress_prefixlength 0
+ table_local=$((table + 1))
+ table_drop=$((table + 2))
+ for proto in -4 -6; do
+ for _table in $table $table_local $table_drop; do
+ while [[ $(ip $proto rule show 2>/dev/null) == *"lookup $_table"* ]]; do
+ cmd ip $proto rule delete lookup $_table
+ done
+ if [[ -n $(ip $proto route show table $_table 2>/dev/null) ]]; then
+ cmd ip $proto route flush table $_table
+ fi
+ done
+ while [[ $(ip $proto rule show 2>/dev/null) == *"from all lookup main suppress_prefixlength 0"* ]]; do
+ cmd ip $proto rule delete lookup main suppress_prefixlength 0
+ done
done
fi
cmd ip link delete dev "$INTERFACE"
@@ -181,31 +189,8 @@ get_fwmark() {
return 0
}
-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
- fi
-}
-
-HAVE_SET_FIREWALL=0
add_default() {
- local table line
+ local table line table_local
if ! get_fwmark table; then
table=51820
while [[ -n $(ip -4 route show table $table 2>/dev/null) || -n $(ip -6 route show table $table 2>/dev/null) ]]; do
@@ -213,32 +198,35 @@ add_default() {
done
cmd wg set "$INTERFACE" fwmark $table
fi
+ table_local=$((table+1))
+ table_drop=$((table+2))
local proto=-4 iptables=iptables pf=ip
[[ $1 == *:* ]] && proto=-6 iptables=ip6tables pf=ip6
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
+ ip link set $INTERFACE group $IFGROUP
+ # this can be done with ip -batch, but this way allows us to use the cmd wrapper
+ ip $proto route show table local dev $INTERFACE | while read route; do
+ cmd ip $proto route add $route dev $INTERFACE table $table_local
+ if [[ "$route" == "local "* ]]; then
+ cmd ip $proto route add blackhole ${route#local} table $table_drop
+ fi
+ done
+ # ip rules are added in reverse priority order, so drop MUST be first
+ cmd ip $proto rule add lookup $table_drop
+ cmd ip $proto rule add iif $INTERFACE lookup $table_local
+ cmd ip $proto rule add iif lo lookup $table_local
+ # pre-state checked in cmd_up
+ if grep -q '^1$' /proc/sys/net/ipv4/conf/*/rp_filter; then
+ cmd sysctl -q net.ipv4.conf.all.rp_filter=2
fi
- HAVE_SET_FIREWALL=1
+ 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
+
return 0
}
@@ -321,6 +309,18 @@ cmd_usage() {
cmd_up() {
local i
[[ -z $(ip link show dev "$INTERFACE" 2>/dev/null) ]] || die "\`$INTERFACE' already exists"
+ if [[ "${ROUTES[*]} " == *"/0 "* ]]; then
+ # do some checks first so we don't have to die in add_default later
+ case "$(ip rule show priority 0)" in
+ $'0:\tfrom all lookup local') ;;
+ $'0:\tfrom all lookup local suppress_ifgroup '$IFGROUP) ;;
+ *) die "ip rule priority 0 must be default or suppress_ifgroup $IFGROUP" ;;
+ esac
+ # most mainstream distros (all systemd-based) set rp_filter=2 by default anyways
+ if grep -q '^1$' /proc/sys/net/ipv4/conf/*/rp_filter; then
+ echo "$PROGRAM: warning: setting net.ipv4.conf.all.rp_filter=2 to support /0 route"
+ fi
+ fi
trap 'del_if; exit' INT TERM EXIT
execute_hooks "${PRE_UP[@]}"
add_if
@@ -343,7 +343,6 @@ cmd_down() {
[[ $SAVE_CONFIG -eq 0 ]] || save_config
del_if
unset_dns || true
- remove_firewall || true
execute_hooks "${POST_DOWN[@]}"
}
--
2.25.1
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