/
backends.go
366 lines (317 loc) · 12.5 KB
/
backends.go
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package main
import (
"errors"
"fmt"
"net"
"os"
"os/exec"
"time"
"github.com/rs/zerolog/log"
)
type backend interface {
initialize() error
ban(ip net.IP, ipv6 bool, d time.Duration) error
finalize() error
}
type ipsetBackend struct {
runner *runner
chainName string
ipset4Name string
ipset6Name string
}
func (b *ipsetBackend) deleteIpsetsAndIptablesEntries() error {
if s, ec, _ := b.runner.executor.execute("iptables", "-D", b.chainName, "-j", "DROP", "-m", "set", "--match-set", b.ipset4Name, "src"); ec > 2 {
return fmt.Errorf(`failed to delete iptables entry for set "%s": %s`, b.ipset4Name, s)
}
if s, ec, _ := b.runner.executor.execute("iptables", "-D", "INPUT", "-j", b.chainName); ec > 2 {
return fmt.Errorf(`failed to delete iptables entry for chain "%s": %s`, b.chainName, s)
}
if s, ec, _ := b.runner.executor.execute("iptables", "-X", b.chainName); ec > 2 {
return fmt.Errorf(`failed to delete iptables chain "%s": %s`, b.chainName, s)
}
if s, ec, _ := b.runner.executor.execute("ip6tables", "-D", b.chainName, "-j", "DROP", "-m", "set", "--match-set", b.ipset6Name, "src"); ec > 2 {
return fmt.Errorf(`failed to delete ip6tables entry for set "%s": %s`, b.ipset6Name, s)
}
if s, ec, _ := b.runner.executor.execute("ip6tables", "-D", "INPUT", "-j", b.chainName); ec > 2 {
return fmt.Errorf(`failed to delete ip6tables entry for chain "%s": %s`, b.chainName, s)
}
if s, ec, _ := b.runner.executor.execute("ip6tables", "-X", b.chainName); ec > 2 {
return fmt.Errorf(`failed to delete ip6tables chain "%s": %s`, b.chainName, s)
}
time.Sleep(250 * time.Millisecond) // Workaround for potential kernel lock problems
if s, ec, _ := b.runner.executor.execute("ipset", "destroy", b.ipset4Name); ec > 1 {
return fmt.Errorf(`failed to destroy ipset "%s": %s`, b.ipset4Name, s)
}
time.Sleep(250 * time.Millisecond) // Workaround for potential kernel lock problems
if s, ec, _ := b.runner.executor.execute("ipset", "destroy", b.ipset6Name); ec > 1 {
return fmt.Errorf(`failed to destroy ipset "%s": %s`, b.ipset6Name, s)
}
return nil
}
func (b *ipsetBackend) createIpsets() error {
time.Sleep(250 * time.Millisecond) // Workaround for potential kernel lock problems
if s, ec, _ := b.runner.executor.execute("ipset", "create", b.ipset4Name, "hash:ip", "timeout", "0"); ec != 0 {
return fmt.Errorf(`failed to create ipset "%s": %s`, b.ipset4Name, s)
}
time.Sleep(250 * time.Millisecond) // Workaround for potential kernel lock problems
if s, ec, _ := b.runner.executor.execute("ipset", "create", b.ipset6Name, "hash:ip", "family", "inet6", "timeout", "0"); ec != 0 {
return fmt.Errorf(`failed to create ipset "%s": %s`, b.ipset6Name, s)
}
return nil
}
func (b *ipsetBackend) createIptablesEntries() error {
if s, ec, _ := b.runner.executor.execute("iptables", "-N", b.chainName); ec != 0 {
return fmt.Errorf(`failed to create iptables chain "%s": %s`, b.chainName, s)
}
if s, ec, _ := b.runner.executor.execute("iptables", "-I", b.chainName, "-j", "DROP", "-m", "set", "--match-set", b.ipset4Name, "src"); ec != 0 {
return fmt.Errorf(`failed to create iptables entry for set "%s": %s`, b.ipset4Name, s)
}
if s, ec, _ := b.runner.executor.execute("iptables", "-I", "INPUT", "-j", b.chainName); ec != 0 {
return fmt.Errorf(`failed to create iptables entry for chain "%s": %s`, b.chainName, s)
}
if s, ec, _ := b.runner.executor.execute("ip6tables", "-N", b.chainName); ec != 0 {
return fmt.Errorf(`failed to create ip6tables chain "%s": %s`, b.chainName, s)
}
if s, ec, _ := b.runner.executor.execute("ip6tables", "-I", b.chainName, "-j", "DROP", "-m", "set", "--match-set", b.ipset6Name, "src"); ec != 0 {
return fmt.Errorf(`failed to create ip6tables entry for set "%s": %s`, b.ipset6Name, s)
}
if s, ec, _ := b.runner.executor.execute("ip6tables", "-I", "INPUT", "-j", b.chainName); ec != 0 {
return fmt.Errorf(`failed to create ip6tables entry for chain "%s": %s`, b.chainName, s)
}
return nil
}
func (b *ipsetBackend) saveIpsets() error {
f, err := os.Create(b.runner.configuration.SaveFilePath)
if err != nil {
return err
}
defer f.Close()
if _, _, err := b.runner.executor.executeWithStd(nil, f, "ipset", "save"); err != nil {
return err
}
// Always ensure file is saved to disk. This should prevent loss of banned IPs on shutdown.
return f.Sync()
}
func (b *ipsetBackend) restoreIpsets() error {
f, err := os.Open(b.runner.configuration.SaveFilePath)
if err != nil {
return err
}
defer func() {
f.Close()
if err := os.Remove(b.runner.configuration.SaveFilePath); err != nil {
log.Warn().Err(err).Msg("failed to delete save file")
}
}()
if _, _, err := b.runner.executor.executeWithStd(f, nil, "ipset", "restore"); err != nil {
return err
}
return nil
}
func (b *ipsetBackend) initialize() error {
b.chainName = "gerberos"
b.ipset4Name = "gerberos4"
b.ipset6Name = "gerberos6"
// Check privileges
if s, _, err := b.runner.executor.execute("ipset", "list"); err != nil {
if errors.Is(err, exec.ErrNotFound) {
return errors.New("ipset: command not found")
}
return fmt.Errorf("ipset: insufficient privileges: %s", s)
}
if s, _, err := b.runner.executor.execute("iptables", "-L"); err != nil {
if errors.Is(err, exec.ErrNotFound) {
return errors.New("iptables: command not found")
}
return fmt.Errorf("iptables: insufficient privileges: %s", s)
}
if s, _, err := b.runner.executor.execute("ip6tables", "-L"); err != nil {
if errors.Is(err, exec.ErrNotFound) {
return errors.New("ip6tables: command not found")
}
return fmt.Errorf("ip6tables: insufficient privileges: %s", s)
}
// Initialize ipsets and ip(6)tables entries
if err := b.deleteIpsetsAndIptablesEntries(); err != nil {
return fmt.Errorf("failed to delete ipsets and iptables entries: %w", err)
}
if b.runner.configuration.SaveFilePath != "" {
if err := b.restoreIpsets(); err != nil {
if err := b.createIpsets(); err != nil {
return fmt.Errorf("failed to create ipsets: %w", err)
}
} else {
log.Info().Str("saveFilePath", b.runner.configuration.SaveFilePath).Msg("restored ipsets")
}
} else {
log.Warn().Msg("not persisting ipsets")
if err := b.createIpsets(); err != nil {
return fmt.Errorf("failed to create ipsets: %w", err)
}
}
if err := b.createIptablesEntries(); err != nil {
return fmt.Errorf("failed to create ip(6)tables entries: %w", err)
}
return nil
}
func (b *ipsetBackend) ban(ip net.IP, ipv6 bool, d time.Duration) error {
s := b.ipset4Name
if ipv6 {
s = b.ipset6Name
}
ds := int64(d.Seconds())
if _, _, err := b.runner.executor.execute("ipset", "test", s, ip.String()); err != nil {
if _, _, err := b.runner.executor.execute("ipset", "add", s, ip.String(), "timeout", fmt.Sprint(ds)); err != nil {
return err
}
}
return nil
}
func (b *ipsetBackend) finalize() error {
if b.runner.configuration.SaveFilePath != "" {
if err := b.saveIpsets(); err != nil {
return fmt.Errorf(`failed to save ipsets to "%s": %w`, b.runner.configuration.SaveFilePath, err)
}
}
if err := b.deleteIpsetsAndIptablesEntries(); err != nil {
return fmt.Errorf("failed to delete ipsets and ip(6)tables entries: %w", err)
}
return nil
}
type nftBackend struct {
runner *runner
table4Name string
table6Name string
set4Name string
set6Name string
}
func (b *nftBackend) createTables() error {
if s, _, err := b.runner.executor.execute("nft", "add", "table", "ip", b.table4Name); err != nil {
return fmt.Errorf(`failed to add table "%s": %s`, b.table4Name, s)
}
if s, _, err := b.runner.executor.execute("nft", "add", "set", "ip", b.table4Name, b.set4Name, "{ type ipv4_addr; flags timeout; }"); err != nil {
return fmt.Errorf(`failed to add ip set "%s": %s`, b.table4Name, s)
}
if s, _, err := b.runner.executor.execute("nft", "add", "chain", "ip", b.table4Name, "input", "{ type filter hook input priority 0; policy accept; }"); err != nil {
return fmt.Errorf(`failed to add input chain: %s`, s)
}
if s, _, err := b.runner.executor.execute("nft", "flush", "chain", "ip", b.table4Name, "input"); err != nil {
return fmt.Errorf(`failed to flush input chain: %s`, s)
}
if s, _, err := b.runner.executor.execute("nft", "add", "rule", "ip", b.table4Name, "input", "ip", "saddr", "@"+b.set4Name, "reject"); err != nil {
return fmt.Errorf(`failed to add rule: %s`, s)
}
if s, _, err := b.runner.executor.execute("nft", "add", "table", "ip6", b.table6Name); err != nil {
return fmt.Errorf(`failed to create ip6 table "%s": %s`, b.table6Name, s)
}
if s, _, err := b.runner.executor.execute("nft", "add", "set", "ip6", b.table6Name, b.set6Name, "{ type ipv6_addr; flags timeout; }"); err != nil {
return fmt.Errorf(`failed to add ip set "%s": %s`, b.table6Name, s)
}
if s, _, err := b.runner.executor.execute("nft", "add", "chain", "ip6", b.table6Name, "input", "{ type filter hook input priority 0; policy accept; }"); err != nil {
return fmt.Errorf(`failed to add input chain: %s`, s)
}
if s, _, err := b.runner.executor.execute("nft", "flush", "chain", "ip6", b.table6Name, "input"); err != nil {
return fmt.Errorf(`failed to flush input chain: %s`, s)
}
if s, _, err := b.runner.executor.execute("nft", "add", "rule", "ip6", b.table6Name, "input", "ip6", "saddr", "@"+b.set6Name, "reject"); err != nil {
return fmt.Errorf(`failed to add rule: %s`, s)
}
return nil
}
func (b *nftBackend) deleteTables() error {
if s, _, err := b.runner.executor.execute("nft", "delete", "table", "ip", b.table4Name); err != nil {
return fmt.Errorf(`failed to delete table "%s": %s`, b.table4Name, s)
}
if s, _, err := b.runner.executor.execute("nft", "delete", "table", "ip6", b.table6Name); err != nil {
return fmt.Errorf(`failed to delete table "%s": %s`, b.table6Name, s)
}
return nil
}
func (b *nftBackend) saveSets() error {
f, err := os.Create(b.runner.configuration.SaveFilePath)
if err != nil {
return err
}
defer f.Close()
if _, _, err := b.runner.executor.executeWithStd(nil, f, "nft", "list", "set", "ip", b.table4Name, b.set4Name); err != nil {
return err
}
if _, _, err := b.runner.executor.executeWithStd(nil, f, "nft", "list", "set", "ip6", b.table6Name, b.set6Name); err != nil {
return err
}
// Always ensure file is saved to disk. This should prevent loss of banned IPs on shutdown.
return f.Sync()
}
func (b *nftBackend) restoreSets() error {
_, _, err := b.runner.executor.execute("nft", "-f", b.runner.configuration.SaveFilePath)
return err
}
func (b *nftBackend) initialize() error {
b.table4Name = "gerberos4"
b.table6Name = "gerberos6"
b.set4Name = "set4"
b.set6Name = "set6"
// Check privileges
if s, _, err := b.runner.executor.execute("nft", "list", "ruleset"); err != nil {
if errors.Is(err, exec.ErrNotFound) {
return errors.New("nft: command not found")
}
return fmt.Errorf("nft: insufficient privileges: %s", s)
}
if err := b.createTables(); err != nil {
return fmt.Errorf("failed to create tables: %w", err)
}
if b.runner.configuration.SaveFilePath != "" {
if err := b.restoreSets(); err != nil {
log.Warn().Str("saveFilePath", b.runner.configuration.SaveFilePath).Err(err).Msg("failed to restore sets")
} else {
log.Info().Str("saveFilePath", b.runner.configuration.SaveFilePath).Msg("restored sets")
}
} else {
log.Warn().Msg("not persisting sets")
}
return nil
}
func (b *nftBackend) ban(ip net.IP, ipv6 bool, d time.Duration) error {
ds := int64(d.Seconds())
t, tn, sn := "ip", b.table4Name, b.set4Name
if ipv6 {
t, tn, sn = "ip6", b.table6Name, b.set6Name
}
if s, ec, err := b.runner.executor.execute("nft", "add", "element", t, tn, sn, fmt.Sprintf("{ %s timeout %ds }", ip, ds)); err != nil {
if ec == 1 {
// This IP is probably already in set. Ignore the error. This is to be reworked
// when support for nft < v1.0.0 is dropped. However, since Ubuntu 20.04 only has
// v0.9.3, this is needed.
return nil
}
return fmt.Errorf(`failed to add element to set "%s": %s`, b.set6Name, s)
}
return nil
}
func (b *nftBackend) finalize() error {
if b.runner.configuration.SaveFilePath != "" {
if err := b.saveSets(); err != nil {
return fmt.Errorf(`failed to save sets to "%s": %w`, b.runner.configuration.SaveFilePath, err)
}
}
if err := b.deleteTables(); err != nil {
return fmt.Errorf("failed to delete tables: %w", err)
}
return nil
}
type testBackend struct {
runner *runner
initializeErr error
banErr error
finalizeErr error
}
func (b *testBackend) initialize() error {
return b.initializeErr
}
func (b *testBackend) ban(ip net.IP, ipv6 bool, d time.Duration) error {
return b.banErr
}
func (b *testBackend) finalize() error {
return b.finalizeErr
}