[FAB-4427] Fix unchecked errors in configtxgen

There was an unchecked file read in configtxgen which caused missing
files to be ignored when read.

This ordinarilly would not have resulted in a crash, but additionally,
the envelope extract utility method did not have a nil check on the
block data, which caused a crash.

This CR fixes both of these issues (adding tests for each).

Change-Id: Ie21b397f86a9c88da4b488c81f3f82df8b2ab3c7
Signed-off-by: Jason Yellick <[email protected]>

Author: Jason Yellick

common/configtx/tool/configtxgen/main.go

@@ -174,6 +174,10 @@ func doOutputAnchorPeersUpdate(conf *genesisconfig.Profile, channelID string, ou
 func doInspectBlock(inspectBlock string) error {
 	logger.Info("Inspecting block")
 	data, err := ioutil.ReadFile(inspectBlock)
+	if err != nil {
+		return fmt.Errorf("Could not read block %s", inspectBlock)
+	}
+
 	logger.Info("Parsing genesis block")
 	block := &cb.Block{}
 	err = proto.Unmarshal(data, block)

common/configtx/tool/configtxgen/main_test.go

@@ -42,6 +42,10 @@ func TestMain(m *testing.M) {
 	os.Exit(testResult)
 }
 
+func TestInspectMissing(t *testing.T) {
+	assert.Error(t, doInspectBlock("NonSenseBlockFileThatDoesn'tActuallyExist"), "Missing block")
+}
+
 func TestInspectBlock(t *testing.T) {
 	blockDest := tmpDir + string(os.PathSeparator) + "block"
 

protos/utils/commonutils.go

@@ -138,6 +138,10 @@ func ExtractEnvelopeOrPanic(block *cb.Block, index int) *cb.Envelope {
 
 // ExtractEnvelope retrieves the requested envelope from a given block and unmarshals it.
 func ExtractEnvelope(block *cb.Block, index int) (*cb.Envelope, error) {
+	if block.Data == nil {
+		return nil, fmt.Errorf("No data in block")
+	}
+
 	envelopeCount := len(block.Data.Data)
 	if index < 0 || index >= envelopeCount {
 		return nil, fmt.Errorf("Envelope index out of bounds")

protos/utils/commonutils_test.go

@@ -153,6 +153,12 @@ func TestUnmarshalEnvelopeOfType(t *testing.T) {
 
 }
 
+func TestExtractEnvelopeNilData(t *testing.T) {
+	block := &cb.Block{}
+	_, err := ExtractEnvelope(block, 0)
+	assert.Error(t, err, "Nil data")
+}
+
 func TestExtractEnvelopeWrongIndex(t *testing.T) {
 	block := testBlock()
 	if _, err := ExtractEnvelope(block, len(block.GetData().Data)); err == nil {