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Fixing extra subnets firewall rules

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- Fix #194
- Fix #190
- Refers to #188
This commit is contained in:
Quentin McGaw
2020-07-13 02:17:49 +00:00
parent 95ad58687d
commit 4a7d341c57
3 changed files with 22 additions and 18 deletions
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8
internal/firewall/enable.go
View File

@@ -102,17 +102,17 @@ func (c *configurator) enable(ctx context.Context) (err error) { //nolint:gocogn
if err = c.acceptOutputThroughInterface(ctx, string(constants.TUN), remove); err != nil {
return fmt.Errorf("cannot enable firewall: %w", err)
}
if err := c.acceptInputFromToSubnet(ctx, localSubnet, "*", remove); err != nil {
if err := c.acceptInputFromSubnetToSubnet(ctx, "*", localSubnet, localSubnet, remove); err != nil {
return fmt.Errorf("cannot enable firewall: %w", err)
}
if err := c.acceptOutputFromToSubnet(ctx, localSubnet, "*", remove); err != nil {
if err := c.acceptOutputFromSubnetToSubnet(ctx, "*", localSubnet, localSubnet, remove); err != nil {
return fmt.Errorf("cannot enable firewall: %w", err)
}
for _, subnet := range c.allowedSubnets {
if err := c.acceptInputFromToSubnet(ctx, subnet, defaultInterface, remove); err != nil {
if err := c.acceptInputFromSubnetToSubnet(ctx, defaultInterface, subnet, localSubnet, remove); err != nil {
return fmt.Errorf("cannot enable firewall: %w", err)
}
if err := c.acceptOutputFromToSubnet(ctx, subnet, defaultInterface, remove); err != nil {
if err := c.acceptOutputFromSubnetToSubnet(ctx, defaultInterface, localSubnet, subnet, remove); err != nil {
return fmt.Errorf("cannot enable firewall: %w", err)
}
}

10
internal/firewall/iptables.go
View File

@@ -112,26 +112,24 @@ func (c *configurator) acceptOutputTrafficToVPN(ctx context.Context, defaultInte
appendOrDelete(remove), connection.IP, defaultInterface, connection.Protocol, connection.Protocol, connection.Port))
}
func (c *configurator) acceptInputFromToSubnet(ctx context.Context, subnet net.IPNet, intf string, remove bool) error {
subnetStr := subnet.String()
func (c *configurator) acceptInputFromSubnetToSubnet(ctx context.Context, intf string, sourceSubnet, destinationSubnet net.IPNet, remove bool) error {
interfaceFlag := "-i " + intf
if intf == "*" { // all interfaces
interfaceFlag = ""
}
return c.runIptablesInstruction(ctx, fmt.Sprintf(
"%s INPUT %s -s %s -d %s -j ACCEPT", appendOrDelete(remove), interfaceFlag, subnetStr, subnetStr,
"%s INPUT %s -s %s -d %s -j ACCEPT", appendOrDelete(remove), interfaceFlag, sourceSubnet.String(), destinationSubnet.String(),
))
}
// Thanks to @npawelek
func (c *configurator) acceptOutputFromToSubnet(ctx context.Context, subnet net.IPNet, intf string, remove bool) error {
subnetStr := subnet.String()
func (c *configurator) acceptOutputFromSubnetToSubnet(ctx context.Context, intf string, sourceSubnet, destinationSubnet net.IPNet, remove bool) error {
interfaceFlag := "-o " + intf
if intf == "*" { // all interfaces
interfaceFlag = ""
}
return c.runIptablesInstruction(ctx, fmt.Sprintf(
"%s OUTPUT %s -s %s -d %s -j ACCEPT", appendOrDelete(remove), interfaceFlag, subnetStr, subnetStr,
"%s OUTPUT %s -s %s -d %s -j ACCEPT", appendOrDelete(remove), interfaceFlag, sourceSubnet.String(), destinationSubnet.String(),
))
}

22
internal/firewall/subnets.go
View File

@@ -32,9 +32,13 @@ func (c *configurator) SetAllowedSubnets(ctx context.Context, subnets []net.IPNe
if err != nil {
return fmt.Errorf("cannot set allowed subnets through firewall: %w", err)
}
localSubnet, err := c.routing.LocalSubnet()
if err != nil {
return fmt.Errorf("cannot set allowed subnets through firewall: %w", err)
}
c.removeSubnets(ctx, subnetsToRemove, defaultInterface)
if err := c.addSubnets(ctx, subnetsToAdd, defaultInterface, defaultGateway); err != nil {
c.removeSubnets(ctx, subnetsToRemove, defaultInterface, localSubnet)
if err := c.addSubnets(ctx, subnetsToAdd, defaultInterface, defaultGateway, localSubnet); err != nil {
return fmt.Errorf("cannot set allowed subnets through firewall: %w", err)
}
@@ -89,15 +93,16 @@ func removeSubnetFromSubnets(subnets []net.IPNet, subnet net.IPNet) []net.IPNet
return subnets
}
func (c *configurator) removeSubnets(ctx context.Context, subnets []net.IPNet, defaultInterface string) {
func (c *configurator) removeSubnets(ctx context.Context, subnets []net.IPNet, defaultInterface string,
localSubnet net.IPNet) {
const remove = true
for _, subnet := range subnets {
failed := false
if err := c.acceptInputFromToSubnet(ctx, subnet, defaultInterface, remove); err != nil {
if err := c.acceptInputFromSubnetToSubnet(ctx, defaultInterface, subnet, localSubnet, remove); err != nil {
failed = true
c.logger.Error("cannot remove outdated allowed subnet through firewall: %s", err)
}
if err := c.acceptOutputFromToSubnet(ctx, subnet, defaultInterface, remove); err != nil {
if err := c.acceptOutputFromSubnetToSubnet(ctx, defaultInterface, subnet, localSubnet, remove); err != nil {
failed = true
c.logger.Error("cannot remove outdated allowed subnet through firewall: %s", err)
}
@@ -112,13 +117,14 @@ func (c *configurator) removeSubnets(ctx context.Context, subnets []net.IPNet, d
}
}
func (c *configurator) addSubnets(ctx context.Context, subnets []net.IPNet, defaultInterface string, defaultGateway net.IP) error {
func (c *configurator) addSubnets(ctx context.Context, subnets []net.IPNet, defaultInterface string,
defaultGateway net.IP, localSubnet net.IPNet) error {
const remove = false
for _, subnet := range subnets {
if err := c.acceptInputFromToSubnet(ctx, subnet, defaultInterface, remove); err != nil {
if err := c.acceptInputFromSubnetToSubnet(ctx, defaultInterface, subnet, localSubnet, remove); err != nil {
return fmt.Errorf("cannot add allowed subnet through firewall: %w", err)
}
if err := c.acceptOutputFromToSubnet(ctx, subnet, defaultInterface, remove); err != nil {
if err := c.acceptOutputFromSubnetToSubnet(ctx, defaultInterface, localSubnet, subnet, remove); err != nil {
return fmt.Errorf("cannot add allowed subnet through firewall: %w", err)
}
if err := c.routing.AddRouteVia(ctx, subnet, defaultGateway, defaultInterface); err != nil {