diff options
Diffstat (limited to 'roles/common/files/usr/local')
| -rwxr-xr-x | roles/common/files/usr/local/sbin/update-firewall.sh | 71 |
1 files changed, 57 insertions, 14 deletions
diff --git a/roles/common/files/usr/local/sbin/update-firewall.sh b/roles/common/files/usr/local/sbin/update-firewall.sh index 8530277..54a66e8 100755 --- a/roles/common/files/usr/local/sbin/update-firewall.sh +++ b/roles/common/files/usr/local/sbin/update-firewall.sh @@ -61,12 +61,26 @@ iptables() { # iptables-restore(8) instead. echo "$@" >> "$new"; } +commit() { + # End a table + echo COMMIT >> "$new" +} inet46() { case "$1" in 4) echo "$2";; 6) echo "$3";; esac } +ipt-chains() { + # Define new (tables and) chains. + while [ $# -gt 0 ]; do + case "$1" in + ?*:*) echo ":${1%:*} ${1##*:} [0:0]";; + ?*) echo "*$1";; + esac + shift + done >> "$new" +} ipt-trim() { # Remove dynamic chain/rules from the input stream, as they are @@ -134,15 +148,17 @@ run() { | sed -nr "/^[0-9]+:\s+(sec[0-9]+)@$if:\s.*/ {s//\1/p;q}" ) # The (host-scoped) IP reserved for IPSec. - local ipsec= + local ipsec= secmark if [ -n "$ifsec" -a $f = 4 ]; then tables+=( [$f]=' mangle nat' ) ipsec=$( /bin/ip -$f address show dev "$ifsec" scope host \ | sed -nr '/^\s+inet\s(\S+).*/ {s//\1/p;q}' ) + secmark=0x1 fi # Store the old (current) ruleset - local old=$(mktemp -t current-rules.v$f.XXXXXX) + local old=$(mktemp -t current-rules.v$f.XXXXXX) \ + new=$(mktemp -t new-rules.v$f.XXXXXX) for table in ${tables[$f]}; do $ipt-save -ct $table done > "$old" @@ -156,14 +172,35 @@ run() { fail2ban=1 fi + if [ -n "$ipsec" ]; then + # We DNAT the IPSec paquets to $ipsec after decapsulation, and + # SNAT them before encapsulation. We need to do the NAT'ing + # before packets enter the IPSec stack because they are signed + # afterwards, and NAT'ing would mess up the signature. + ipt-chains mangle PREROUTING:ACCEPT INPUT:ACCEPT \ + FORWARD:DROP \ + OUTPUT:ACCEPT POSTROUTING:ACCEPT + # Mark all IPSec packets to keep track of them and NAT them + # after decapsulation. Unmarked packets that are to be sent to + # $ipsec are dropped. + iptables -A PREROUTING -p esp -j MARK --set-mark $secmark + iptables -A INPUT -d "$ipsec" -m mark \! --mark $secmark -j DROP + commit + + ipt-chains nat PREROUTING:ACCEPT INPUT:ACCEPT \ + OUTPUT:ACCEPT POSTROUTING:ACCEPT + # DNAT all marked packets that have been decapsulated. Packets + # originating from our IPSec are SNAT'ed (MASQUERADE). We cannot + # mark them here (it won't survivethe NAT'ing), but any reply + # not going through IPSec would be dropped (since unmarked). + iptables -A PREROUTING \! -p esp -m mark --mark "$secmark" \ + -j DNAT --to "${ipsec%/*}" + iptables -A POSTROUTING -s "$ipsec" -j MASQUERADE + commit + fi + # The usual chains in filter, along with the desired default policies. - local new=$(mktemp -t new-rules.v$f.XXXXXX) - cat > "$new" <<- EOF - *filter - :INPUT DROP [0:0] - :FORWARD DROP [0:0] - :OUTPUT DROP [0:0] - EOF + ipt-chains filter INPUT:DROP FORWARD:DROP OUTPUT:DROP if [ -z "$if" ]; then # If the interface is not configured, we stop here and DROP all @@ -238,6 +275,14 @@ run() { iptables -A INPUT -i lo -s "$localhost" -d "$localhost" -j ACCEPT iptables -A OUTPUT -o lo -s "$localhost" -d "$localhost" -j ACCEPT + if [ -n "$ipsec" ]; then + # ACCEPT any, *marked* traffic destinating to the non-routable + # $ipsec. Also ACCEPT all traffic originating from $ipsec, as it + # is MASQUERADE'd. + iptables -A INPUT -i "$if" -d "$ipsec" -m mark --mark "$secmark" -j ACCEPT + iptables -A OUTPUT -s "$ipsec" -o "$if" -j ACCEPT + fi + # Prepare fail2ban. We make fail2ban insert its rules in a dedicated # chain, so that it doesn't mess up the existing rules. [ $fail2ban -eq 1 ] && iptables -A INPUT -i $if -j fail2ban @@ -296,11 +341,9 @@ run() { done ######################################################################## + commit - # Commit the table 'filter'. - echo COMMIT >> "$new" - local rv1=0 rv2=0 persistent=/etc/iptables/rules.v$f local oldz=$(mktemp -t current-rules.v$f.XXXXXX) @@ -311,7 +354,7 @@ run() { -e 's/^\[[0-9]+:[0-9]+\]\s+//' \ "$old" > "$oldz" - /usr/bin/uniq "$new" | /bin/ip netns exec $netns $ipt-restore + /usr/bin/uniq "$new" | /bin/ip netns exec $netns $ipt-restore || ipt-revert for table in ${tables[$f]}; do /bin/ip netns exec $netns $ipt-save -t $table @@ -327,7 +370,7 @@ run() { local update="Please run '${0##*/}'." if [ $check -eq 0 ]; then - /usr/bin/uniq "$new" | $ipt-restore + /usr/bin/uniq "$new" | $ipt-restore || ipt-revert else if [ $rv1 -ne 0 ]; then log "WARN: The IPv$f firewall is not up to date! $update" |