Merge pull request #45920 from thaJeztah/fix_expose_npe

daemon/containerd: fix assignment to entry in nil map during commit

daemon/containerd/image_import.go

@@ -393,8 +393,11 @@ func containerConfigToOciImageConfig(cfg *container.Config) ocispec.ImageConfig
 		StopSignal:  cfg.StopSignal,
 		ArgsEscaped: cfg.ArgsEscaped,
 	}
-	for k, v := range cfg.ExposedPorts {
-		ociCfg.ExposedPorts[string(k)] = v
+	if len(cfg.ExposedPorts) > 0 {
+		ociCfg.ExposedPorts = map[string]struct{}{}
+		for k, v := range cfg.ExposedPorts {
+			ociCfg.ExposedPorts[string(k)] = v
+		}
 	}
 
 	return ociCfg

daemon/containerd/image_import_test.go

@@ -0,0 +1,22 @@
+package containerd
+
+import (
+	"testing"
+
+	"github.com/docker/docker/api/types/container"
+	"github.com/docker/go-connections/nat"
+	"gotest.tools/v3/assert"
+	is "gotest.tools/v3/assert/cmp"
+)
+
+// regression test for https://github.com/moby/moby/issues/45904
+func TestContainerConfigToOciImageConfig(t *testing.T) {
+	ociCFG := containerConfigToOciImageConfig(&container.Config{
+		ExposedPorts: nat.PortSet{
+			"80/tcp": struct{}{},
+		},
+	})
+
+	expected := map[string]struct{}{"80/tcp": {}}
+	assert.Check(t, is.DeepEqual(ociCFG.ExposedPorts, expected))
+}