select: restrict dbnum in [0, 15]

include/pika_command.h

@@ -271,6 +271,7 @@ public:
     kPurgeExist,
     kInvalidParameter,
     kWrongNum,
+    kInvalidIndex,
     kErrOther,
   };
 
@@ -332,6 +333,9 @@ public:
       result.append(message_);
       result.append("' command\r\n");
       break;
+    case kInvalidIndex:
+      result = "-ERR invalid DB index\r\n";
+      break;
     case kErrOther:
       result = "-ERR ";
       result.append(message_);

src/pika_admin.cc

@@ -268,8 +268,9 @@ void SelectCmd::DoInitial(PikaCmdArgsType &argv, const CmdInfo* const ptr_info)
   }
 
   int64_t db_id;
-  if (!slash::string2l(argv[1].data(), argv[1].size(), &db_id)) {
-    res_.SetRes(CmdRes::kInvalidInt);
+  if (!slash::string2l(argv[1].data(), argv[1].size(), &db_id) || 
+      db_id < 0 || db_id > 15) {
+    res_.SetRes(CmdRes::kInvalidIndex);
   }
 }
 void SelectCmd::Do() {