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[1.17] ipmasq: fix race causing potential concurrent map read/write. #619

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Merged
antonipp merged 1 commit into from
Aug 12, 2025
Merged

[1.17] ipmasq: fix race causing potential concurrent map read/write. #619

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16 changes: 14 additions & 2 deletions pkg/ipmasq/ipmasq.go
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Original file line number Diff line number Diff line change
Expand Up @@ -16,6 +16,7 @@ import (
"github.com/fsnotify/fsnotify"
"k8s.io/apimachinery/pkg/util/yaml"

"github.com/cilium/cilium/pkg/lock"
"github.com/cilium/cilium/pkg/logging"
"github.com/cilium/cilium/pkg/logging/logfields"
)
Expand Down Expand Up @@ -88,6 +89,8 @@ type IPMasqMap interface {

// IPMasqAgent represents a state of the ip-masq-agent
type IPMasqAgent struct {
lock lock.Mutex

configPath string
masqLinkLocalIPv4 bool
masqLinkLocalIPv6 bool
Expand All @@ -113,6 +116,9 @@ func NewIPMasqAgent(configPath string, ipMasqMap IPMasqMap) *IPMasqAgent {
// Start starts the ip-masq-agent goroutine which tracks the config file and
// updates the BPF map accordingly.
func (a *IPMasqAgent) Start() error {
a.lock.Lock()
defer a.lock.Unlock()

watcher, err := fsnotify.NewWatcher()
if err != nil {
return fmt.Errorf("failed to create fsnotify watcher: %w", err)
Expand All @@ -130,7 +136,7 @@ func (a *IPMasqAgent) Start() error {
if err := a.restore(); err != nil {
log.WithError(err).Warn("Failed to restore")
}
if err := a.Update(); err != nil {
if err := a.update(); err != nil {
log.WithError(err).Warn("Failed to update")
}

Expand Down Expand Up @@ -175,8 +181,14 @@ func (a *IPMasqAgent) Stop() {
a.watcher.Close()
}

// Update updates the ipmasq BPF map entries with ones from the config file.
func (a *IPMasqAgent) Update() error {
a.lock.Lock()
defer a.lock.Unlock()
return a.update()
}

// Update updates the ipmasq BPF map entries with ones from the config file.
func (a *IPMasqAgent) update() error {
isEmpty, err := a.readConfig()
if err != nil {
return err
Expand Down
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