Trim long MSP plaintext messages in logs

This changeset trims the MSP plaintext message in the log statement
to the beginning and end of the byte array if its length is greater
than 32. Logging the entire plaintext for very long messages can
lead to the process hanging when deploying chaincode.

https://jira.hyperledger.org/browse/FAB-1870

Change-Id: I0d169df859c0be97090c86ff73f014d813ea7cdd
Signed-off-by: Will Lahti <wtlahti@us.ibm.com>

msp/identities.go

@@ -157,7 +157,13 @@ func (id *signingidentity) Sign(msg []byte) ([]byte, error) {
 		return nil, fmt.Errorf("Failed computing digest [%s]", err)
 	}
 
-	mspLogger.Debugf("Sign: plaintext: %X \n", msg)
+	// TODO - consider removing these debug statements in the future as they may
+	// contain confidential information
+	if len(msg) < 32 {
+		mspLogger.Debugf("Sign: plaintext: %X \n", msg)
+	} else {
+		mspLogger.Debugf("Sign: plaintext: %X...%X \n", msg[0:16], msg[len(msg)-16:])
+	}
 	mspLogger.Debugf("Sign: digest: %X \n", digest)
 
 	// Sign

msp/msp_test.go

@@ -155,6 +155,45 @@ func TestSignAndVerify(t *testing.T) {
 	}
 }
 
+func TestSignAndVerify_longMessage(t *testing.T) {
+	id, err := localMsp.GetDefaultSigningIdentity()
+	if err != nil {
+		t.Fatalf("GetSigningIdentity should have succeeded")
+		return
+	}
+
+	serializedID, err := id.Serialize()
+	if err != nil {
+		t.Fatalf("Serialize should have succeeded")
+		return
+	}
+
+	idBack, err := localMsp.DeserializeIdentity(serializedID)
+	if err != nil {
+		t.Fatalf("DeserializeIdentity should have succeeded")
+		return
+	}
+
+	msg := []byte("ABCDEFGABCDEFGABCDEFGABCDEFGABCDEFGABCDEFGABCDEFGABCDEFGABCDEFGABCDEFGABCDEFGABCDEFGABCDEFGABCDEFG")
+	sig, err := id.Sign(msg)
+	if err != nil {
+		t.Fatalf("Sign should have succeeded")
+		return
+	}
+
+	err = id.Verify(msg, sig)
+	if err != nil {
+		t.Fatalf("The signature should be valid")
+		return
+	}
+
+	err = idBack.Verify(msg, sig)
+	if err != nil {
+		t.Fatalf("The signature should be valid")
+		return
+	}
+}
+
 func TestMain(m *testing.M) {
 	retVal := m.Run()
 	os.Exit(retVal)