[http] analyze arguments of cmd.json

While here arbitrary string injected into ProcessLine,
ensure that only numeric argument is not quoted.
All other arguments kinds will be quoted and prevent execution of potentially dangerous code

Author: linev

net/http/src/TRootSniffer.cxx

@@ -32,6 +32,8 @@
 #include <memory>
 #include <vector>
 #include <cstring>
+#include <cctype>
+
 
 const char *item_prop_kind = "_kind";
 const char *item_prop_more = "_more";
@@ -1216,9 +1218,41 @@ Bool_t TRootSniffer::ExecuteCmd(const std::string &path, const std::string &opti
             return kTRUE;
          }
 
-         TString svalue = DecodeUrlOptionValue(argvalue, kTRUE);
          argname = TString("%") + argname + TString("%");
-         method.ReplaceAll(argname, svalue);
+         auto p = method.Index(argname);
+         if (p == kNPOS)
+            continue;
+
+         method.Remove(p, argname.Length());
+
+         if ((p > 0) && (p < method.Length()) && (method.Length() > 1) && (method[p-1] == '"') && (method[p] == '"')) {
+            // command definition has quotes around argument
+            // one can insert value from URL removing quotes
+            method.Insert(p, DecodeUrlOptionValue(argvalue, kTRUE));
+            continue;
+         }
+
+         // extract argument without removing quotes
+         TString svalue = DecodeUrlOptionValue(argvalue, kFALSE);
+
+         if ((svalue.Length() > 1) && (svalue[0] == '"') && (svalue[svalue.Length() - 1] == '"')) {
+            // if value itself has quotes, all special symbols already escaped and one can insert it as is
+            method.Insert(p, svalue);
+            continue;
+         }
+
+         Bool_t is_numeric = kTRUE;
+         // expect decimal, hex or float values here, E/e also belong to hex
+         for(Size_t i = 0; is_numeric && (i < svalue.Length()); ++i)
+            is_numeric = std::isxdigit(svalue[i]) || std::strchr(".+-", svalue[i]);
+
+         // always quote content which not numeric
+         if (!is_numeric)
+            svalue = "\"" + svalue + "\"";
+         else if (svalue.IsNull())
+            svalue = "0";
+
+         method.Insert(p, svalue);
       }
    }