mirror of
https://github.com/netbirdio/netbird.git
synced 2024-11-29 19:43:57 +01:00
474 lines
13 KiB
Go
474 lines
13 KiB
Go
package iptables
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import (
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"fmt"
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"net"
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"strconv"
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"github.com/coreos/go-iptables/iptables"
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"github.com/google/uuid"
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"github.com/nadoo/ipset"
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log "github.com/sirupsen/logrus"
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firewall "github.com/netbirdio/netbird/client/firewall/manager"
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)
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const (
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tableName = "filter"
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// rules chains contains the effective ACL rules
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chainNameInputRules = "NETBIRD-ACL-INPUT"
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chainNameOutputRules = "NETBIRD-ACL-OUTPUT"
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postRoutingMark = "0x000007e4"
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)
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type aclManager struct {
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iptablesClient *iptables.IPTables
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wgIface iFaceMapper
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routeingFwChainName string
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entries map[string][][]string
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ipsetStore *ipsetStore
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}
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func newAclManager(iptablesClient *iptables.IPTables, wgIface iFaceMapper, routeingFwChainName string) (*aclManager, error) {
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m := &aclManager{
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iptablesClient: iptablesClient,
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wgIface: wgIface,
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routeingFwChainName: routeingFwChainName,
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entries: make(map[string][][]string),
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ipsetStore: newIpsetStore(),
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}
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err := ipset.Init()
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if err != nil {
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return nil, fmt.Errorf("failed to init ipset: %w", err)
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}
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m.seedInitialEntries()
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err = m.cleanChains()
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if err != nil {
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return nil, err
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}
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err = m.createDefaultChains()
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if err != nil {
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return nil, err
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}
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return m, nil
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}
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func (m *aclManager) AddFiltering(
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ip net.IP,
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protocol firewall.Protocol,
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sPort *firewall.Port,
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dPort *firewall.Port,
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direction firewall.RuleDirection,
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action firewall.Action,
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ipsetName string,
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) ([]firewall.Rule, error) {
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var dPortVal, sPortVal string
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if dPort != nil && dPort.Values != nil {
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// TODO: we support only one port per rule in current implementation of ACLs
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dPortVal = strconv.Itoa(dPort.Values[0])
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}
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if sPort != nil && sPort.Values != nil {
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sPortVal = strconv.Itoa(sPort.Values[0])
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}
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var chain string
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if direction == firewall.RuleDirectionOUT {
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chain = chainNameOutputRules
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} else {
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chain = chainNameInputRules
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}
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ipsetName = transformIPsetName(ipsetName, sPortVal, dPortVal)
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specs := filterRuleSpecs(ip, string(protocol), sPortVal, dPortVal, direction, action, ipsetName)
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if ipsetName != "" {
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if ipList, ipsetExists := m.ipsetStore.ipset(ipsetName); ipsetExists {
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if err := ipset.Add(ipsetName, ip.String()); err != nil {
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return nil, fmt.Errorf("failed to add IP to ipset: %w", err)
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}
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// if ruleset already exists it means we already have the firewall rule
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// so we need to update IPs in the ruleset and return new fw.Rule object for ACL manager.
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ipList.addIP(ip.String())
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return []firewall.Rule{&Rule{
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ruleID: uuid.New().String(),
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ipsetName: ipsetName,
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ip: ip.String(),
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chain: chain,
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specs: specs,
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}}, nil
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}
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if err := ipset.Flush(ipsetName); err != nil {
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log.Errorf("flush ipset %s before use it: %s", ipsetName, err)
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}
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if err := ipset.Create(ipsetName); err != nil {
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return nil, fmt.Errorf("failed to create ipset: %w", err)
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}
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if err := ipset.Add(ipsetName, ip.String()); err != nil {
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return nil, fmt.Errorf("failed to add IP to ipset: %w", err)
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}
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ipList := newIpList(ip.String())
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m.ipsetStore.addIpList(ipsetName, ipList)
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}
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ok, err := m.iptablesClient.Exists("filter", chain, specs...)
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if err != nil {
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return nil, fmt.Errorf("failed to check rule: %w", err)
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}
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if ok {
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return nil, fmt.Errorf("rule already exists")
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}
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if err := m.iptablesClient.Insert("filter", chain, 1, specs...); err != nil {
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return nil, err
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}
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rule := &Rule{
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ruleID: uuid.New().String(),
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specs: specs,
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ipsetName: ipsetName,
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ip: ip.String(),
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chain: chain,
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}
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if !shouldAddToPrerouting(protocol, dPort, direction) {
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return []firewall.Rule{rule}, nil
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}
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rulePrerouting, err := m.addPreroutingFilter(ipsetName, string(protocol), dPortVal, ip)
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if err != nil {
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return []firewall.Rule{rule}, err
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}
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return []firewall.Rule{rule, rulePrerouting}, nil
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}
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// DeleteRule from the firewall by rule definition
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func (m *aclManager) DeleteRule(rule firewall.Rule) error {
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r, ok := rule.(*Rule)
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if !ok {
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return fmt.Errorf("invalid rule type")
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}
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if r.chain == "PREROUTING" {
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goto DELETERULE
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}
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if ipsetList, ok := m.ipsetStore.ipset(r.ipsetName); ok {
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// delete IP from ruleset IPs list and ipset
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if _, ok := ipsetList.ips[r.ip]; ok {
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if err := ipset.Del(r.ipsetName, r.ip); err != nil {
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return fmt.Errorf("failed to delete ip from ipset: %w", err)
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}
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delete(ipsetList.ips, r.ip)
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}
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// if after delete, set still contains other IPs,
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// no need to delete firewall rule and we should exit here
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if len(ipsetList.ips) != 0 {
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return nil
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}
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// we delete last IP from the set, that means we need to delete
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// set itself and associated firewall rule too
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m.ipsetStore.deleteIpset(r.ipsetName)
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if err := ipset.Destroy(r.ipsetName); err != nil {
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log.Errorf("delete empty ipset: %v", err)
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}
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}
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DELETERULE:
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var table string
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if r.chain == "PREROUTING" {
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table = "mangle"
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} else {
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table = "filter"
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}
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err := m.iptablesClient.Delete(table, r.chain, r.specs...)
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if err != nil {
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log.Debugf("failed to delete rule, %s, %v: %s", r.chain, r.specs, err)
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}
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return err
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}
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func (m *aclManager) Reset() error {
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return m.cleanChains()
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}
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func (m *aclManager) addPreroutingFilter(ipsetName string, protocol string, port string, ip net.IP) (*Rule, error) {
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var src []string
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if ipsetName != "" {
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src = []string{"-m", "set", "--set", ipsetName, "src"}
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} else {
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src = []string{"-s", ip.String()}
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}
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specs := []string{
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"-d", m.wgIface.Address().IP.String(),
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"-p", protocol,
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"--dport", port,
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"-j", "MARK", "--set-mark", postRoutingMark,
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}
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specs = append(src, specs...)
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ok, err := m.iptablesClient.Exists("mangle", "PREROUTING", specs...)
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if err != nil {
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return nil, fmt.Errorf("failed to check rule: %w", err)
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}
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if ok {
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return nil, fmt.Errorf("rule already exists")
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}
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if err := m.iptablesClient.Insert("mangle", "PREROUTING", 1, specs...); err != nil {
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return nil, err
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}
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rule := &Rule{
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ruleID: uuid.New().String(),
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specs: specs,
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ipsetName: ipsetName,
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ip: ip.String(),
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chain: "PREROUTING",
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}
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return rule, nil
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}
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// todo write less destructive cleanup mechanism
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func (m *aclManager) cleanChains() error {
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ok, err := m.iptablesClient.ChainExists(tableName, chainNameOutputRules)
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if err != nil {
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log.Debugf("failed to list chains: %s", err)
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return err
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}
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if ok {
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rules := m.entries["OUTPUT"]
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for _, rule := range rules {
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err := m.iptablesClient.DeleteIfExists(tableName, "OUTPUT", rule...)
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if err != nil {
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log.Errorf("failed to delete rule: %v, %s", rule, err)
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}
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}
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err = m.iptablesClient.ClearAndDeleteChain(tableName, chainNameOutputRules)
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if err != nil {
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log.Debugf("failed to clear and delete %s chain: %s", chainNameOutputRules, err)
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return err
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}
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}
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ok, err = m.iptablesClient.ChainExists(tableName, chainNameInputRules)
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if err != nil {
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log.Debugf("failed to list chains: %s", err)
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return err
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}
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if ok {
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for _, rule := range m.entries["INPUT"] {
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err := m.iptablesClient.DeleteIfExists(tableName, "INPUT", rule...)
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if err != nil {
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log.Errorf("failed to delete rule: %v, %s", rule, err)
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}
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}
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for _, rule := range m.entries["FORWARD"] {
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err := m.iptablesClient.DeleteIfExists(tableName, "FORWARD", rule...)
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if err != nil {
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log.Errorf("failed to delete rule: %v, %s", rule, err)
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}
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}
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err = m.iptablesClient.ClearAndDeleteChain(tableName, chainNameInputRules)
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if err != nil {
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log.Debugf("failed to clear and delete %s chain: %s", chainNameInputRules, err)
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return err
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}
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}
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ok, err = m.iptablesClient.ChainExists("mangle", "PREROUTING")
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if err != nil {
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log.Debugf("failed to list chains: %s", err)
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return err
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}
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if ok {
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for _, rule := range m.entries["PREROUTING"] {
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err := m.iptablesClient.DeleteIfExists("mangle", "PREROUTING", rule...)
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if err != nil {
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log.Errorf("failed to delete rule: %v, %s", rule, err)
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}
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}
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err = m.iptablesClient.ClearChain("mangle", "PREROUTING")
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if err != nil {
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log.Debugf("failed to clear %s chain: %s", "PREROUTING", err)
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return err
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}
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}
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for _, ipsetName := range m.ipsetStore.ipsetNames() {
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if err := ipset.Flush(ipsetName); err != nil {
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log.Errorf("flush ipset %q during reset: %v", ipsetName, err)
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}
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if err := ipset.Destroy(ipsetName); err != nil {
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log.Errorf("delete ipset %q during reset: %v", ipsetName, err)
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}
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m.ipsetStore.deleteIpset(ipsetName)
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}
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return nil
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}
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func (m *aclManager) createDefaultChains() error {
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// chain netbird-acl-input-rules
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if err := m.iptablesClient.NewChain(tableName, chainNameInputRules); err != nil {
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log.Debugf("failed to create '%s' chain: %s", chainNameInputRules, err)
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return err
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}
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// chain netbird-acl-output-rules
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if err := m.iptablesClient.NewChain(tableName, chainNameOutputRules); err != nil {
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log.Debugf("failed to create '%s' chain: %s", chainNameOutputRules, err)
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return err
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}
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for chainName, rules := range m.entries {
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for _, rule := range rules {
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if chainName == "FORWARD" {
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// position 2 because we add it after router's, jump rule
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if err := m.iptablesClient.InsertUnique(tableName, "FORWARD", 2, rule...); err != nil {
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log.Debugf("failed to create input chain jump rule: %s", err)
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return err
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}
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} else {
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if err := m.iptablesClient.AppendUnique(tableName, chainName, rule...); err != nil {
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log.Debugf("failed to create input chain jump rule: %s", err)
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return err
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}
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}
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}
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}
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return nil
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}
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func (m *aclManager) seedInitialEntries() {
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m.appendToEntries("INPUT",
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[]string{"-i", m.wgIface.Name(), "!", "-s", m.wgIface.Address().String(), "-d", m.wgIface.Address().String(), "-j", "ACCEPT"})
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m.appendToEntries("INPUT",
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[]string{"-i", m.wgIface.Name(), "-s", m.wgIface.Address().String(), "!", "-d", m.wgIface.Address().String(), "-j", "ACCEPT"})
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m.appendToEntries("INPUT",
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[]string{"-i", m.wgIface.Name(), "-s", m.wgIface.Address().String(), "-d", m.wgIface.Address().String(), "-j", chainNameInputRules})
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m.appendToEntries("INPUT", []string{"-i", m.wgIface.Name(), "-j", "DROP"})
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m.appendToEntries("OUTPUT",
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[]string{"-o", m.wgIface.Name(), "!", "-s", m.wgIface.Address().String(), "-d", m.wgIface.Address().String(), "-j", "ACCEPT"})
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m.appendToEntries("OUTPUT",
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[]string{"-o", m.wgIface.Name(), "-s", m.wgIface.Address().String(), "!", "-d", m.wgIface.Address().String(), "-j", "ACCEPT"})
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m.appendToEntries("OUTPUT",
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[]string{"-o", m.wgIface.Name(), "-s", m.wgIface.Address().String(), "-d", m.wgIface.Address().String(), "-j", chainNameOutputRules})
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m.appendToEntries("OUTPUT", []string{"-o", m.wgIface.Name(), "-j", "DROP"})
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m.appendToEntries("FORWARD", []string{"-i", m.wgIface.Name(), "-j", "DROP"})
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m.appendToEntries("FORWARD", []string{"-i", m.wgIface.Name(), "-j", chainNameInputRules})
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m.appendToEntries("FORWARD",
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[]string{"-o", m.wgIface.Name(), "-m", "mark", "--mark", postRoutingMark, "-j", "ACCEPT"})
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m.appendToEntries("FORWARD",
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[]string{"-i", m.wgIface.Name(), "-m", "mark", "--mark", postRoutingMark, "-j", "ACCEPT"})
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m.appendToEntries("FORWARD", []string{"-o", m.wgIface.Name(), "-j", m.routeingFwChainName})
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m.appendToEntries("FORWARD", []string{"-i", m.wgIface.Name(), "-j", m.routeingFwChainName})
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m.appendToEntries("PREROUTING",
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[]string{"-t", "mangle", "-i", m.wgIface.Name(), "!", "-s", m.wgIface.Address().String(), "-d", m.wgIface.Address().IP.String(), "-m", "mark", "--mark", postRoutingMark})
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}
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func (m *aclManager) appendToEntries(chainName string, spec []string) {
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m.entries[chainName] = append(m.entries[chainName], spec)
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}
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// filterRuleSpecs returns the specs of a filtering rule
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func filterRuleSpecs(
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ip net.IP, protocol string, sPort, dPort string, direction firewall.RuleDirection, action firewall.Action, ipsetName string,
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) (specs []string) {
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matchByIP := true
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// don't use IP matching if IP is ip 0.0.0.0
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if ip.String() == "0.0.0.0" {
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matchByIP = false
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}
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switch direction {
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case firewall.RuleDirectionIN:
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if matchByIP {
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if ipsetName != "" {
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specs = append(specs, "-m", "set", "--set", ipsetName, "src")
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} else {
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specs = append(specs, "-s", ip.String())
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}
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}
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case firewall.RuleDirectionOUT:
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if matchByIP {
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if ipsetName != "" {
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specs = append(specs, "-m", "set", "--set", ipsetName, "dst")
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} else {
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specs = append(specs, "-d", ip.String())
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}
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}
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}
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if protocol != "all" {
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specs = append(specs, "-p", protocol)
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}
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if sPort != "" {
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specs = append(specs, "--sport", sPort)
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}
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if dPort != "" {
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specs = append(specs, "--dport", dPort)
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}
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return append(specs, "-j", actionToStr(action))
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}
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func actionToStr(action firewall.Action) string {
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if action == firewall.ActionAccept {
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return "ACCEPT"
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}
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return "DROP"
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}
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func transformIPsetName(ipsetName string, sPort, dPort string) string {
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switch {
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case ipsetName == "":
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return ""
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case sPort != "" && dPort != "":
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return ipsetName + "-sport-dport"
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case sPort != "":
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return ipsetName + "-sport"
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case dPort != "":
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return ipsetName + "-dport"
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default:
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return ipsetName
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}
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}
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func shouldAddToPrerouting(proto firewall.Protocol, dPort *firewall.Port, direction firewall.RuleDirection) bool {
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if proto == "all" {
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return false
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}
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if direction != firewall.RuleDirectionIN {
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return false
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}
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if dPort == nil {
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return false
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}
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return true
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}
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