fix: prevent panic in nocloud platform code

The bug was logical: first the check was done for one of the values to
be non-nil, and after that one of the values was assumed to be non-nil,
while it could have been nil.

While fixing that, linter figured out that raw metadata config is never
needed outside of `acquireConfig`, so this got dropped as well,
simplifying the code even more.

Fixes #9578

Signed-off-by: Andrey Smirnov <andrey.smirnov@siderolabs.com>
(cherry picked from commit 3a0a17a)

internal/app/machined/pkg/runtime/v1alpha1/platform/nocloud/metadata.go

@@ -215,10 +215,10 @@ func (n *Nocloud) configFromCD(ctx context.Context, r state.State) (metaConfig [
 }
 
 //nolint:gocyclo
-func (n *Nocloud) acquireConfig(ctx context.Context, r state.State) (metadataConfigDl, metadataNetworkConfigDl, machineConfigDl []byte, metadata *MetadataConfig, err error) {
+func (n *Nocloud) acquireConfig(ctx context.Context, r state.State) (metadataNetworkConfigDl, machineConfigDl []byte, metadata *MetadataConfig, err error) {
 	s, err := smbios.GetSMBIOSInfo()
 	if err != nil {
-		return nil, nil, nil, nil, err
+		return nil, nil, nil, err
 	}
 
 	var (
@@ -252,6 +252,8 @@ func (n *Nocloud) acquireConfig(ctx context.Context, r state.State) (metadataCon
 		}
 	}
 
+	var metadataConfigDl []byte
+
 	if networkSource && metaBaseURL != "" {
 		metadataConfigDl, metadataNetworkConfigDl, machineConfigDl, err = n.configFromNetwork(ctx, metaBaseURL, r)
 	} else {
@@ -277,7 +279,7 @@ func (n *Nocloud) acquireConfig(ctx context.Context, r state.State) (metadataCon
 		metadata.InternalDNS = fallbackMetadata.InternalDNS
 	}
 
-	return metadataConfigDl, metadataNetworkConfigDl, machineConfigDl, metadata, err
+	return metadataNetworkConfigDl, machineConfigDl, metadata, err
 }
 
 //nolint:gocyclo,cyclop

internal/app/machined/pkg/runtime/v1alpha1/platform/nocloud/nocloud.go

@@ -81,7 +81,7 @@ func (n *Nocloud) ParseMetadata(unmarshalledNetworkConfig *NetworkConfig, st sta
 
 // Configuration implements the runtime.Platform interface.
 func (n *Nocloud) Configuration(ctx context.Context, r state.State) ([]byte, error) {
-	_, _, machineConfigDl, _, err := n.acquireConfig(ctx, r) //nolint:dogsled
+	_, machineConfigDl, _, err := n.acquireConfig(ctx, r)
 	if err != nil {
 		return nil, err
 	}
@@ -108,7 +108,7 @@ func (n *Nocloud) KernelArgs(string) procfs.Parameters {
 
 // NetworkConfiguration implements the runtime.Platform interface.
 func (n *Nocloud) NetworkConfiguration(ctx context.Context, st state.State, ch chan<- *runtime.PlatformNetworkConfig) error {
-	metadataConfigDl, metadataNetworkConfigDl, _, metadata, err := n.acquireConfig(ctx, st)
+	metadataNetworkConfigDl, _, metadata, err := n.acquireConfig(ctx, st)
 	if stderrors.Is(err, errors.ErrNoConfigSource) {
 		err = nil
 	}
@@ -117,20 +117,14 @@ func (n *Nocloud) NetworkConfiguration(ctx context.Context, st state.State, ch c
 		return err
 	}
 
-	if metadataConfigDl == nil && metadataNetworkConfigDl == nil {
+	if metadataNetworkConfigDl == nil {
 		// no data, use cached network configuration if available
 		return nil
 	}
 
-	var unmarshalledNetworkConfig *NetworkConfig
-
-	if metadataNetworkConfigDl != nil {
-		nc, err := DecodeNetworkConfig(metadataNetworkConfigDl)
-		if err != nil {
-			return err
-		}
-
-		unmarshalledNetworkConfig = nc
+	unmarshalledNetworkConfig, err := DecodeNetworkConfig(metadataNetworkConfigDl)
+	if err != nil {
+		return err
 	}
 
 	networkConfig, err := n.ParseMetadata(unmarshalledNetworkConfig, st, metadata)