[FAB-3344] Fix CSCC error messages

This commit fixes the error messages of the CSCC:

1. JoinChannel call provided with genesis block, hence args[1] is a
block and not channel it as expected in error message, hence to prevent
putting entire block into error message, channel id is extracted
instead.

2. GetChannel doesn't get any parameters and therefore in order to avoid
panic on accessing non existing args[1], this part of error message is
removed.

Change-Id: Ifcfc543afa5d694c963a65d688056e4d072b9379
Signed-off-by: Artem Barger <bartem@il.ibm.com>

core/scc/cscc/configure.go

@@ -107,7 +107,14 @@ func (e *PeerConfiger) Invoke(stub shim.ChaincodeStubInterface) pb.Response {
 	case JoinChain:
 		// 2. check local MSP Admins policy
 		if err = e.policyChecker.CheckPolicyNoChannel(mgmt.Admins, sp); err != nil {
-			return shim.Error(fmt.Sprintf("\"JoinChain\" request failed authorization check for channel [%s]: [%s]", args[1], err))
+			cid, e := utils.GetChainIDFromBlockBytes(args[1])
+			errorString := fmt.Sprintf("\"JoinChain\" request failed authorization check "+
+				"for channel [%s]: [%s]", cid, err)
+			if e != nil {
+				errorString = fmt.Sprintf("\"JoinChain\" request failed authorization [%s] and unable "+
+					"to extract channel id from the block due to [%s]", err, e)
+			}
+			return shim.Error(errorString)
 		}
 
 		return joinChain(args[1])
@@ -127,7 +134,7 @@ func (e *PeerConfiger) Invoke(stub shim.ChaincodeStubInterface) pb.Response {
 	case GetChannels:
 		// 2. check local MSP Members policy
 		if err = e.policyChecker.CheckPolicyNoChannel(mgmt.Members, sp); err != nil {
-			return shim.Error(fmt.Sprintf("\"GetChannels\" request failed authorization check for channel [%s]: [%s]", args[1], err))
+			return shim.Error(fmt.Sprintf("\"GetChannels\" request failed authorization check: [%s]", err))
 		}
 
 		return getChannels()

protos/utils/blockutils.go

@@ -23,6 +23,16 @@ import (
 	cb "github.com/hyperledger/fabric/protos/common"
 )
 
+// GetChainIDFromBlockBytes returns chain ID given byte array which represents the block
+func GetChainIDFromBlockBytes(bytes []byte) (string, error) {
+	block, err := GetBlockFromBlockBytes(bytes)
+	if err != nil {
+		return "", err
+	}
+
+	return GetChainIDFromBlock(block)
+}
+
 // GetChainIDFromBlock returns chain ID in the block
 func GetChainIDFromBlock(block *cb.Block) (string, error) {
 	if block.Data == nil || block.Data.Data == nil || len(block.Data.Data) == 0 {