* [PATCH 1/6] firewall: Split CONNTRACK chain
@ 2024-04-18 21:11 Michael Tremer
2024-04-18 21:11 ` [PATCH 2/6] firewall: Don't filter output INVALID packets Michael Tremer
` (4 more replies)
0 siblings, 5 replies; 6+ messages in thread
From: Michael Tremer @ 2024-04-18 21:11 UTC (permalink / raw)
To: development
[-- Attachment #1: Type: text/plain, Size: 1647 bytes --]
This is preparation to handle incoming/outgoing packets differently.
Signed-off-by: Michael Tremer <michael.tremer(a)ipfire.org>
---
src/initscripts/system/firewall | 19 ++++++++++++-------
1 file changed, 12 insertions(+), 7 deletions(-)
diff --git a/src/initscripts/system/firewall b/src/initscripts/system/firewall
index 69bdcb594..d14466ef0 100644
--- a/src/initscripts/system/firewall
+++ b/src/initscripts/system/firewall
@@ -149,10 +149,15 @@ iptables_init() {
fi
iptables -A CTINVALID -j DROP -m comment --comment "DROP_CTINVALID"
- iptables -N CONNTRACK
- iptables -A CONNTRACK -m conntrack --ctstate ESTABLISHED -j ACCEPT
- iptables -A CONNTRACK -m conntrack --ctstate INVALID -j CTINVALID
- iptables -A CONNTRACK -p icmp -m conntrack --ctstate RELATED -j ACCEPT
+ iptables -N CTINPUT
+ iptables -A CTINPUT -m conntrack --ctstate ESTABLISHED -j ACCEPT
+ iptables -A CTINPUT -m conntrack --ctstate INVALID -j CTINVALID
+ iptables -A CTINPUT -p icmp -m conntrack --ctstate RELATED -j ACCEPT
+
+ iptables -N CTOUTPUT
+ iptables -A CTOUTPUT -m conntrack --ctstate ESTABLISHED -j ACCEPT
+ iptables -A CTOUTPUT -m conntrack --ctstate INVALID -j CTINVALID
+ iptables -A CTOUTPUT -p icmp -m conntrack --ctstate RELATED -j ACCEPT
# Restore any connection marks
iptables -t mangle -A PREROUTING -j CONNMARK --restore-mark
@@ -261,9 +266,9 @@ iptables_init() {
done
# Accept everything connected
- for i in INPUT FORWARD OUTPUT; do
- iptables -A ${i} -j CONNTRACK
- done
+ iptables -A INPUT -j CTINPUT
+ iptables -A FORWARD -j CTINPUT
+ iptables -A OUTPUT -j CTOUTPUT
# Allow DHCP
iptables -N DHCPINPUT
--
2.39.2
^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH 2/6] firewall: Don't filter output INVALID packets
2024-04-18 21:11 [PATCH 1/6] firewall: Split CONNTRACK chain Michael Tremer
@ 2024-04-18 21:11 ` Michael Tremer
2024-04-18 21:11 ` [PATCH 3/6] firewall: Enable SYNPROXY for untracked packets Michael Tremer
` (3 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: Michael Tremer @ 2024-04-18 21:11 UTC (permalink / raw)
To: development
[-- Attachment #1: Type: text/plain, Size: 760 bytes --]
This should never cause any problems, but will cause that certain more
complicated featured like SYNPROXY won't work.
Signed-off-by: Michael Tremer <michael.tremer(a)ipfire.org>
---
src/initscripts/system/firewall | 1 -
1 file changed, 1 deletion(-)
diff --git a/src/initscripts/system/firewall b/src/initscripts/system/firewall
index d14466ef0..054d58c01 100644
--- a/src/initscripts/system/firewall
+++ b/src/initscripts/system/firewall
@@ -156,7 +156,6 @@ iptables_init() {
iptables -N CTOUTPUT
iptables -A CTOUTPUT -m conntrack --ctstate ESTABLISHED -j ACCEPT
- iptables -A CTOUTPUT -m conntrack --ctstate INVALID -j CTINVALID
iptables -A CTOUTPUT -p icmp -m conntrack --ctstate RELATED -j ACCEPT
# Restore any connection marks
--
2.39.2
^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH 3/6] firewall: Enable SYNPROXY for untracked packets
2024-04-18 21:11 [PATCH 1/6] firewall: Split CONNTRACK chain Michael Tremer
2024-04-18 21:11 ` [PATCH 2/6] firewall: Don't filter output INVALID packets Michael Tremer
@ 2024-04-18 21:11 ` Michael Tremer
2024-04-18 21:11 ` [PATCH 4/6] firewall.cgi: Add a checkbox to enable SYN flood protection Michael Tremer
` (2 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: Michael Tremer @ 2024-04-18 21:11 UTC (permalink / raw)
To: development
[-- Attachment #1: Type: text/plain, Size: 1232 bytes --]
This enables some DoS protection using SYNPROXY which will complete a
SYN handshake with the client before the connection is being forwarded.
Signed-off-by: Michael Tremer <michael.tremer(a)ipfire.org>
---
src/initscripts/system/firewall | 16 ++++++++++++++++
1 file changed, 16 insertions(+)
diff --git a/src/initscripts/system/firewall b/src/initscripts/system/firewall
index 054d58c01..1250b9ff4 100644
--- a/src/initscripts/system/firewall
+++ b/src/initscripts/system/firewall
@@ -46,6 +46,20 @@ IPS_BYPASS_MASK="0x40000000"
IPSET_DB_DIR="/var/lib/location/ipset"
+SYNPROXY_OPTIONS=(
+ # Allow clients to use Selective ACKs
+ "--sack-perm"
+
+ # Allow TCP Timestamps
+ #"--timestamp"
+
+ # Window Scaling
+ "--wscale" "9"
+
+ # Maximum Segment Size
+ "--mss" "1460"
+)
+
function iptables() {
/sbin/iptables --wait "$@"
}
@@ -151,6 +165,8 @@ iptables_init() {
iptables -N CTINPUT
iptables -A CTINPUT -m conntrack --ctstate ESTABLISHED -j ACCEPT
+ iptables -A CTINPUT -m conntrack --ctstate INVALID,UNTRACKED \
+ -p tcp -j SYNPROXY "${SYNPROXY_OPTIONS[@]}"
iptables -A CTINPUT -m conntrack --ctstate INVALID -j CTINVALID
iptables -A CTINPUT -p icmp -m conntrack --ctstate RELATED -j ACCEPT
--
2.39.2
^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH 4/6] firewall.cgi: Add a checkbox to enable SYN flood protection
2024-04-18 21:11 [PATCH 1/6] firewall: Split CONNTRACK chain Michael Tremer
2024-04-18 21:11 ` [PATCH 2/6] firewall: Don't filter output INVALID packets Michael Tremer
2024-04-18 21:11 ` [PATCH 3/6] firewall: Enable SYNPROXY for untracked packets Michael Tremer
@ 2024-04-18 21:11 ` Michael Tremer
2024-04-18 21:11 ` [PATCH 5/6] firewall: Implement generating SYNPROXY rules Michael Tremer
2024-04-18 21:11 ` [PATCH 6/6] sysctl: Conntrack: Disable picking up loose TCP connections Michael Tremer
4 siblings, 0 replies; 6+ messages in thread
From: Michael Tremer @ 2024-04-18 21:11 UTC (permalink / raw)
To: development
[-- Attachment #1: Type: text/plain, Size: 16136 bytes --]
Signed-off-by: Michael Tremer <michael.tremer(a)ipfire.org>
---
doc/language_issues.de | 1 +
doc/language_issues.en | 1 +
doc/language_issues.es | 1 +
doc/language_issues.fr | 1 +
doc/language_issues.it | 1 +
doc/language_issues.nl | 1 +
doc/language_issues.pl | 1 +
doc/language_issues.ru | 1 +
doc/language_issues.tr | 1 +
doc/language_missings | 8 ++++++++
html/cgi-bin/firewall.cgi | 14 ++++++++++++--
langs/en/cgi-bin/en.pl | 1 +
12 files changed, 30 insertions(+), 2 deletions(-)
diff --git a/doc/language_issues.de b/doc/language_issues.de
index 1ba77c94d..79b21fe24 100644
--- a/doc/language_issues.de
+++ b/doc/language_issues.de
@@ -894,6 +894,7 @@ WARNING: untranslated string: enable disable client = unknown string
WARNING: untranslated string: enable disable dyndns = unknown string
WARNING: untranslated string: error message = unknown string
WARNING: untranslated string: error the to date has to be later than the from date = The to date has to be later than the from date!
+WARNING: untranslated string: fwdfw syn flood protection = Enable SYN Flood Protection (TCP only)
WARNING: untranslated string: fwhost cust locationgrp = unknown string
WARNING: untranslated string: fwhost err hostip = unknown string
WARNING: untranslated string: guardian block a host = unknown string
diff --git a/doc/language_issues.en b/doc/language_issues.en
index 84bc8cdb0..2541ccf88 100644
--- a/doc/language_issues.en
+++ b/doc/language_issues.en
@@ -890,6 +890,7 @@ WARNING: untranslated string: fwdfw rulepos = Rule position
WARNING: untranslated string: fwdfw snat = Source NAT
WARNING: untranslated string: fwdfw source = Source
WARNING: untranslated string: fwdfw sourceip = Source address (MAC/IP address or network):
+WARNING: untranslated string: fwdfw syn flood protection = Enable SYN Flood Protection (TCP only)
WARNING: untranslated string: fwdfw target = Destination
WARNING: untranslated string: fwdfw targetip = Destination address (IP address or network):
WARNING: untranslated string: fwdfw timeframe = Use time constraints
diff --git a/doc/language_issues.es b/doc/language_issues.es
index 25ef7f9c5..4949d9335 100644
--- a/doc/language_issues.es
+++ b/doc/language_issues.es
@@ -958,6 +958,7 @@ WARNING: untranslated string: extrahd mounted = Mounted
WARNING: untranslated string: extrahd no mount point given = No mount point given
WARNING: untranslated string: extrahd not configured = Not configured
WARNING: untranslated string: extrahd not mounted = Not mounted
+WARNING: untranslated string: fwdfw syn flood protection = Enable SYN Flood Protection (TCP only)
WARNING: untranslated string: fwhost cust locationgrp = unknown string
WARNING: untranslated string: fwhost err hostip = unknown string
WARNING: untranslated string: guardian block a host = unknown string
diff --git a/doc/language_issues.fr b/doc/language_issues.fr
index 7aafc3053..fb29de25c 100644
--- a/doc/language_issues.fr
+++ b/doc/language_issues.fr
@@ -912,6 +912,7 @@ WARNING: untranslated string: enable disable client = unknown string
WARNING: untranslated string: enable disable dyndns = unknown string
WARNING: untranslated string: error message = unknown string
WARNING: untranslated string: extrahd because it is outside the allowed mount path = unknown string
+WARNING: untranslated string: fwdfw syn flood protection = Enable SYN Flood Protection (TCP only)
WARNING: untranslated string: fwhost cust locationgrp = unknown string
WARNING: untranslated string: fwhost err hostip = unknown string
WARNING: untranslated string: guardian block a host = unknown string
diff --git a/doc/language_issues.it b/doc/language_issues.it
index 7498e2af1..680cc5f4e 100644
--- a/doc/language_issues.it
+++ b/doc/language_issues.it
@@ -1029,6 +1029,7 @@ WARNING: untranslated string: fwdfw limitconcon = Limit concurrent connections p
WARNING: untranslated string: fwdfw maxconcon = Max. concurrent connections
WARNING: untranslated string: fwdfw numcon = Number of connections
WARNING: untranslated string: fwdfw ratelimit = Rate-limit new connections
+WARNING: untranslated string: fwdfw syn flood protection = Enable SYN Flood Protection (TCP only)
WARNING: untranslated string: fwhost addlocationgrp = Add new Location group
WARNING: untranslated string: fwhost cust location = Location Groups
WARNING: untranslated string: fwhost cust locationgroup = Location Groups
diff --git a/doc/language_issues.nl b/doc/language_issues.nl
index 16e69bf27..de9dc112a 100644
--- a/doc/language_issues.nl
+++ b/doc/language_issues.nl
@@ -1035,6 +1035,7 @@ WARNING: untranslated string: fwdfw limitconcon = Limit concurrent connections p
WARNING: untranslated string: fwdfw maxconcon = Max. concurrent connections
WARNING: untranslated string: fwdfw numcon = Number of connections
WARNING: untranslated string: fwdfw ratelimit = Rate-limit new connections
+WARNING: untranslated string: fwdfw syn flood protection = Enable SYN Flood Protection (TCP only)
WARNING: untranslated string: fwhost addlocationgrp = Add new Location group
WARNING: untranslated string: fwhost cust location = Location Groups
WARNING: untranslated string: fwhost cust locationgroup = Location Groups
diff --git a/doc/language_issues.pl b/doc/language_issues.pl
index 31c64c164..d52c29f6b 100644
--- a/doc/language_issues.pl
+++ b/doc/language_issues.pl
@@ -1093,6 +1093,7 @@ WARNING: untranslated string: fwdfw rulepos = Rule position
WARNING: untranslated string: fwdfw snat = Source NAT
WARNING: untranslated string: fwdfw source = Source
WARNING: untranslated string: fwdfw sourceip = Source address (MAC/IP address or network):
+WARNING: untranslated string: fwdfw syn flood protection = Enable SYN Flood Protection (TCP only)
WARNING: untranslated string: fwdfw target = Destination
WARNING: untranslated string: fwdfw targetip = Destination address (IP address or network):
WARNING: untranslated string: fwdfw timeframe = Use time constraints
diff --git a/doc/language_issues.ru b/doc/language_issues.ru
index 9495d951e..3436c4a6e 100644
--- a/doc/language_issues.ru
+++ b/doc/language_issues.ru
@@ -1090,6 +1090,7 @@ WARNING: untranslated string: fwdfw rulepos = Rule position
WARNING: untranslated string: fwdfw snat = Source NAT
WARNING: untranslated string: fwdfw source = Source
WARNING: untranslated string: fwdfw sourceip = Source address (MAC/IP address or network):
+WARNING: untranslated string: fwdfw syn flood protection = Enable SYN Flood Protection (TCP only)
WARNING: untranslated string: fwdfw target = Destination
WARNING: untranslated string: fwdfw targetip = Destination address (IP address or network):
WARNING: untranslated string: fwdfw timeframe = Use time constraints
diff --git a/doc/language_issues.tr b/doc/language_issues.tr
index a2c134a2a..ca57075b1 100644
--- a/doc/language_issues.tr
+++ b/doc/language_issues.tr
@@ -977,6 +977,7 @@ WARNING: untranslated string: force enable = Forced
WARNING: untranslated string: foreshadow = Foreshadow
WARNING: untranslated string: fw red = Firewall options for RED interface
WARNING: untranslated string: fwdfw all subnets = All subnets
+WARNING: untranslated string: fwdfw syn flood protection = Enable SYN Flood Protection (TCP only)
WARNING: untranslated string: fwhost cust locationgrp = unknown string
WARNING: untranslated string: fwhost err hostip = unknown string
WARNING: untranslated string: generate ptr = Generate PTR
diff --git a/doc/language_missings b/doc/language_missings
index 44d79f352..a214b8f9a 100644
--- a/doc/language_missings
+++ b/doc/language_missings
@@ -56,6 +56,7 @@
< enable
< error the to date has to be later than the from date
< extrahd because it it outside the allowed mount path
+< fwdfw syn flood protection
< g.dtm
< g.lite
< hostile networks in
@@ -120,6 +121,7 @@
< extrahd no mount point given
< extrahd not configured
< extrahd not mounted
+< fwdfw syn flood protection
< hardware vulnerabilities
< hostile networks in
< hostile networks out
@@ -148,6 +150,7 @@
< bewan adsl pci st
< bewan adsl usb
< extrahd because it it outside the allowed mount path
+< fwdfw syn flood protection
< g.dtm
< g.lite
< hostile networks total
@@ -365,6 +368,7 @@
< fwdfw maxconcon
< fwdfw numcon
< fwdfw ratelimit
+< fwdfw syn flood protection
< fwhost addlocationgrp
< fwhost cust location
< fwhost cust locationgroup
@@ -894,6 +898,7 @@
< fwdfw maxconcon
< fwdfw numcon
< fwdfw ratelimit
+< fwdfw syn flood protection
< fwhost addlocationgrp
< fwhost cust location
< fwhost cust locationgroup
@@ -1613,6 +1618,7 @@
< fwdfw source
< fwdfw sourceip
< fwdfw std network
+< fwdfw syn flood protection
< fwdfw target
< fwdfw targetip
< fwdfw till
@@ -2613,6 +2619,7 @@
< fwdfw source
< fwdfw sourceip
< fwdfw std network
+< fwdfw syn flood protection
< fwdfw target
< fwdfw targetip
< fwdfw till
@@ -3327,6 +3334,7 @@
< force enable
< foreshadow
< fwdfw all subnets
+< fwdfw syn flood protection
< fw red
< generate ptr
< hardware vulnerabilities
diff --git a/html/cgi-bin/firewall.cgi b/html/cgi-bin/firewall.cgi
index 681d42770..226d00838 100644
--- a/html/cgi-bin/firewall.cgi
+++ b/html/cgi-bin/firewall.cgi
@@ -301,8 +301,8 @@ if ($fwdfwsettings{'ACTION'} eq 'saverule')
#check if we have an identical rule already
if($fwdfwsettings{'oldrulenumber'} eq $fwdfwsettings{'rulepos'}){
foreach my $key (sort keys %rulehash){
- if ( "$fwdfwsettings{'RULE_ACTION'},$fwdfwsettings{'ACTIVE'},$fwdfwsettings{'grp1'},$fwdfwsettings{$fwdfwsettings{'grp1'}},$fwdfwsettings{'grp2'},$fwdfwsettings{$fwdfwsettings{'grp2'}},$fwdfwsettings{'USE_SRC_PORT'},$fwdfwsettings{'PROT'},$fwdfwsettings{'ICMP_TYPES'},$fwdfwsettings{'SRC_PORT'},$fwdfwsettings{'USESRV'},$fwdfwsettings{'TGT_PROT'},$fwdfwsettings{'ICMP_TGT'},$fwdfwsettings{'grp3'},$fwdfwsettings{$fwdfwsettings{'grp3'}},$fwdfwsettings{'ruleremark'},$fwdfwsettings{'LOG'},$fwdfwsettings{'TIME'},$fwdfwsettings{'TIME_MON'},$fwdfwsettings{'TIME_TUE'},$fwdfwsettings{'TIME_WED'},$fwdfwsettings{'TIME_THU'},$fwdfwsettings{'TIME_FRI'},$fwdfwsettings{'TIME_SAT'},$fwdfwsettings{'TIME_SUN'},$fwdfwsettings{'TIME_FROM'},$fwdfwsettings{'TIME_TO'},$fwdfwsettings{'USE_NAT'},$fwdfwsettings{$fwdfwsettings{'nat'}},$fwdfwsettings{'dnatport'},$fwdfwsettings{'nat'},$fwdfwsettings{'LIMIT_CON_CON'},$fwdfwsettings{'concon'},$fwdfwsettings{'RATE_LIMIT'},$fwdfwsettings{'ratecon'},$fwdfwsettings{'RATETIME'}"
- eq "$rulehash{$key}[0],$rulehash{$key}[2],$rulehash{$key}[3],$rulehash{$key}[4],$rulehash{$key}[5],$rulehash{$key}[6],$rulehash{$key}[7],$rulehash{$key}[8],$rulehash{$key}[9],$rulehash{$key}[10],$rulehash{$key}[11],$rulehash{$key}[12],$rulehash{$key}[13],$rulehash{$key}[14],$rulehash{$key}[15],$rulehash{$key}[16],$rulehash{$key}[17],$rulehash{$key}[18],$rulehash{$key}[19],$rulehash{$key}[20],$rulehash{$key}[21],$rulehash{$key}[22],$rulehash{$key}[23],$rulehash{$key}[24],$rulehash{$key}[25],$rulehash{$key}[26],$rulehash{$key}[27],$rulehash{$key}[28],$rulehash{$key}[29],$rulehash{$key}[30],$rulehash{$key}[31],$rulehash{$key}[32],$rulehash{$key}[33],$rulehash{$key}[34],$rulehash{$key}[35],$rulehash{$key}[36]"){
+ if ( "$fwdfwsettings{'RULE_ACTION'},$fwdfwsettings{'ACTIVE'},$fwdfwsettings{'grp1'},$fwdfwsettings{$fwdfwsettings{'grp1'}},$fwdfwsettings{'grp2'},$fwdfwsettings{$fwdfwsettings{'grp2'}},$fwdfwsettings{'USE_SRC_PORT'},$fwdfwsettings{'PROT'},$fwdfwsettings{'ICMP_TYPES'},$fwdfwsettings{'SRC_PORT'},$fwdfwsettings{'USESRV'},$fwdfwsettings{'TGT_PROT'},$fwdfwsettings{'ICMP_TGT'},$fwdfwsettings{'grp3'},$fwdfwsettings{$fwdfwsettings{'grp3'}},$fwdfwsettings{'ruleremark'},$fwdfwsettings{'LOG'},$fwdfwsettings{'TIME'},$fwdfwsettings{'TIME_MON'},$fwdfwsettings{'TIME_TUE'},$fwdfwsettings{'TIME_WED'},$fwdfwsettings{'TIME_THU'},$fwdfwsettings{'TIME_FRI'},$fwdfwsettings{'TIME_SAT'},$fwdfwsettings{'TIME_SUN'},$fwdfwsettings{'TIME_FROM'},$fwdfwsettings{'TIME_TO'},$fwdfwsettings{'USE_NAT'},$fwdfwsettings{$fwdfwsettings{'nat'}},$fwdfwsettings{'dnatport'},$fwdfwsettings{'nat'},$fwdfwsettings{'LIMIT_CON_CON'},$fwdfwsettings{'concon'},$fwdfwsettings{'RATE_LIMIT'},$fwdfwsettings{'ratecon'},$fwdfwsettings{'RATETIME'},$fwdfwsettings{'SYN_FLOOD_PROTECTION'}"
+ eq "$rulehash{$key}[0],$rulehash{$key}[2],$rulehash{$key}[3],$rulehash{$key}[4],$rulehash{$key}[5],$rulehash{$key}[6],$rulehash{$key}[7],$rulehash{$key}[8],$rulehash{$key}[9],$rulehash{$key}[10],$rulehash{$key}[11],$rulehash{$key}[12],$rulehash{$key}[13],$rulehash{$key}[14],$rulehash{$key}[15],$rulehash{$key}[16],$rulehash{$key}[17],$rulehash{$key}[18],$rulehash{$key}[19],$rulehash{$key}[20],$rulehash{$key}[21],$rulehash{$key}[22],$rulehash{$key}[23],$rulehash{$key}[24],$rulehash{$key}[25],$rulehash{$key}[26],$rulehash{$key}[27],$rulehash{$key}[28],$rulehash{$key}[29],$rulehash{$key}[30],$rulehash{$key}[31],$rulehash{$key}[32],$rulehash{$key}[33],$rulehash{$key}[34],$rulehash{$key}[35],$rulehash{$key}[36],$rulehash{$key}[37]"){
$errormessage.=$Lang::tr{'fwdfw err ruleexists'};
if($fwdfwsettings{'oldruleremark'} ne $fwdfwsettings{'ruleremark'} && $fwdfwsettings{'updatefwrule'} eq 'on' && $fwdfwsettings{'ruleremark'} ne '' && !&validremark($fwdfwsettings{'ruleremark'})){
$errormessage=$Lang::tr{'fwdfw err remark'}."<br>";
@@ -1624,6 +1624,7 @@ sub newrule
$fwdfwsettings{'RATE_LIMIT'} = $hash{$key}[34];
$fwdfwsettings{'ratecon'} = $hash{$key}[35];
$fwdfwsettings{'RATETIME'} = $hash{$key}[36];
+ $fwdfwsettings{'SYN_FLOOD_PROTECTION'} = $hash{$key}[37];
$checked{'grp1'}{$fwdfwsettings{'grp1'}} = 'CHECKED';
$checked{'grp2'}{$fwdfwsettings{'grp2'}} = 'CHECKED';
$checked{'grp3'}{$fwdfwsettings{'grp3'}} = 'CHECKED';
@@ -1631,6 +1632,7 @@ sub newrule
$checked{'USESRV'}{$fwdfwsettings{'USESRV'}} = 'CHECKED';
$checked{'ACTIVE'}{$fwdfwsettings{'ACTIVE'}} = 'CHECKED';
$checked{'LOG'}{$fwdfwsettings{'LOG'}} = 'CHECKED';
+ $checked{'SYN_FLOOD_PROTECTION'}{$fwdfwsettings{'SYN_FLOOD_PROTECTION'}} = 'CHECKED';
$checked{'TIME'}{$fwdfwsettings{'TIME'}} = 'CHECKED';
$checked{'TIME_MON'}{$fwdfwsettings{'TIME_MON'}} = 'CHECKED';
$checked{'TIME_TUE'}{$fwdfwsettings{'TIME_TUE'}} = 'CHECKED';
@@ -2070,6 +2072,12 @@ END
</td>
<td>$Lang::tr{'fwdfw log rule'}</td>
</tr>
+ <tr>
+ <td>
+ <input type='checkbox' name='SYN_FLOOD_PROTECTION' value='ON' $checked{'SYN_FLOOD_PROTECTION'}{'ON'}>
+ </td>
+ <td>$Lang::tr{'fwdfw syn flood protection'}</td>
+ </tr>
<tr>
<td width='1%'>
<input type='checkbox' name='TIME' id="USE_TIME_CONSTRAINTS" value='ON' $checked{'TIME'}{'ON'}>
@@ -2341,6 +2349,7 @@ sub saverule
$$hash{$key}[34] = $fwdfwsettings{'RATE_LIMIT'};
$$hash{$key}[35] = $fwdfwsettings{'ratecon'};
$$hash{$key}[36] = $fwdfwsettings{'RATETIME'};
+ $$hash{$key}[37] = $fwdfwsettings{'SYN_FLOOD_PROTECTION'};
&General::writehasharray("$config", $hash);
}else{
foreach my $key (sort {$a <=> $b} keys %$hash){
@@ -2382,6 +2391,7 @@ sub saverule
$$hash{$key}[34] = $fwdfwsettings{'RATE_LIMIT'};
$$hash{$key}[35] = $fwdfwsettings{'ratecon'};
$$hash{$key}[36] = $fwdfwsettings{'RATETIME'};
+ $$hash{$key}[37] = $fwdfwsettings{'SYN_FLOOD_PROTECTION'};
last;
}
}
diff --git a/langs/en/cgi-bin/en.pl b/langs/en/cgi-bin/en.pl
index ee3a6c5aa..6e3a01555 100644
--- a/langs/en/cgi-bin/en.pl
+++ b/langs/en/cgi-bin/en.pl
@@ -1246,6 +1246,7 @@
'fwdfw source' => 'Source',
'fwdfw sourceip' => 'Source address (MAC/IP address or network):',
'fwdfw std network' => 'Standard networks:',
+'fwdfw syn flood protection' => 'Enable SYN Flood Protection (TCP only)',
'fwdfw target' => 'Destination',
'fwdfw targetip' => 'Destination address (IP address or network):',
'fwdfw till' => 'Until:',
--
2.39.2
^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH 5/6] firewall: Implement generating SYNPROXY rules
2024-04-18 21:11 [PATCH 1/6] firewall: Split CONNTRACK chain Michael Tremer
` (2 preceding siblings ...)
2024-04-18 21:11 ` [PATCH 4/6] firewall.cgi: Add a checkbox to enable SYN flood protection Michael Tremer
@ 2024-04-18 21:11 ` Michael Tremer
2024-04-18 21:11 ` [PATCH 6/6] sysctl: Conntrack: Disable picking up loose TCP connections Michael Tremer
4 siblings, 0 replies; 6+ messages in thread
From: Michael Tremer @ 2024-04-18 21:11 UTC (permalink / raw)
To: development
[-- Attachment #1: Type: text/plain, Size: 1996 bytes --]
Signed-off-by: Michael Tremer <michael.tremer(a)ipfire.org>
---
config/firewall/rules.pl | 12 ++++++++++++
src/initscripts/system/firewall | 4 ++++
2 files changed, 16 insertions(+)
diff --git a/config/firewall/rules.pl b/config/firewall/rules.pl
index a47c260a1..e38f77242 100644
--- a/config/firewall/rules.pl
+++ b/config/firewall/rules.pl
@@ -297,6 +297,9 @@ sub buildrules {
$NAT_MODE = uc($$hash{$key}[31]);
}
+ # Enable SYN flood protection?
+ my $SYN_FLOOD_PROTECTION = 0;
+
# Set up time constraints.
my @time_options = ();
if ($$hash{$key}[18] eq 'ON') {
@@ -370,6 +373,11 @@ sub buildrules {
}
}
+ # DoS Protection
+ if (($elements ge 38) && ($$hash{$key}[37] eq "ON")) {
+ $SYN_FLOOD_PROTECTION = 1;
+ }
+
# Check which protocols are used in this rule and so that we can
# later group rules by protocols.
my @protocols = &get_protocols($hash, $key);
@@ -608,6 +616,10 @@ sub buildrules {
}
run("$IPTABLES -A $chain @options @source_intf_options @destination_intf_options -j $target");
+ if ($SYN_FLOOD_PROTECTION && ($protocol eq "tcp")) {
+ run("$IPTABLES -t raw -A SYN_FLOOD_PROTECT @options -j CT --notrack");
+ }
+
# Handle forwarding rules and add corresponding rules for firewall access.
if ($chain eq $CHAIN_FORWARD) {
# If the firewall is part of the destination subnet and access to the destination network
diff --git a/src/initscripts/system/firewall b/src/initscripts/system/firewall
index 1250b9ff4..6727e4a20 100644
--- a/src/initscripts/system/firewall
+++ b/src/initscripts/system/firewall
@@ -407,6 +407,10 @@ iptables_init() {
iptables -t nat -N REDNAT
iptables -t nat -A POSTROUTING -j REDNAT
+ # SYN Flood Protection
+ iptables -t raw -N SYN_FLOOD_PROTECT
+ iptables -t raw -A PREROUTING -p tcp --syn -j SYN_FLOOD_PROTECT
+
# Populate IPsec chains
/usr/lib/firewall/ipsec-policy
--
2.39.2
^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH 6/6] sysctl: Conntrack: Disable picking up loose TCP connections
2024-04-18 21:11 [PATCH 1/6] firewall: Split CONNTRACK chain Michael Tremer
` (3 preceding siblings ...)
2024-04-18 21:11 ` [PATCH 5/6] firewall: Implement generating SYNPROXY rules Michael Tremer
@ 2024-04-18 21:11 ` Michael Tremer
4 siblings, 0 replies; 6+ messages in thread
From: Michael Tremer @ 2024-04-18 21:11 UTC (permalink / raw)
To: development
[-- Attachment #1: Type: text/plain, Size: 615 bytes --]
Signed-off-by: Michael Tremer <michael.tremer(a)ipfire.org>
---
config/etc/sysctl.conf | 3 +++
1 file changed, 3 insertions(+)
diff --git a/config/etc/sysctl.conf b/config/etc/sysctl.conf
index 31a220e38..e35ee0dc4 100644
--- a/config/etc/sysctl.conf
+++ b/config/etc/sysctl.conf
@@ -35,6 +35,9 @@ net.ipv6.conf.default.disable_ipv6 = 1
net.ipv6.conf.all.accept_redirects = 0
net.ipv6.conf.default.accept_redirects = 0
+# Do not try to pick up existing TCP connections in conntrack
+net.netfilter.nf_conntrack_tcp_loose = 0
+
# Enable netfilter accounting
net.netfilter.nf_conntrack_acct = 1
--
2.39.2
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2024-04-18 21:11 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2024-04-18 21:11 [PATCH 1/6] firewall: Split CONNTRACK chain Michael Tremer
2024-04-18 21:11 ` [PATCH 2/6] firewall: Don't filter output INVALID packets Michael Tremer
2024-04-18 21:11 ` [PATCH 3/6] firewall: Enable SYNPROXY for untracked packets Michael Tremer
2024-04-18 21:11 ` [PATCH 4/6] firewall.cgi: Add a checkbox to enable SYN flood protection Michael Tremer
2024-04-18 21:11 ` [PATCH 5/6] firewall: Implement generating SYNPROXY rules Michael Tremer
2024-04-18 21:11 ` [PATCH 6/6] sysctl: Conntrack: Disable picking up loose TCP connections Michael Tremer
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