HADOOP-18573. Improve error reporting on non-standard kerberos names (#5221)

The kerberos RPC does not declare any restriction on
characters used in kerberos names, though
implementations MAY be more restrictive.

If the kerberos controller supports use non-conventional
principal names *and the kerberos admin chooses to use them*
this can confuse some of the parsing.

The obvious solution is for the enterprise admins to "not do that"
as a lot of things break, bits of hadoop included.

Harden the hadoop code slightly so at least we fail more gracefully,
so people can then get in touch with their sysadmin and tell them
to stop it.

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/security/ShellBasedIdMapping.java

@@ -37,6 +37,8 @@ import org.apache.hadoop.thirdparty.com.google.common.collect.HashBiMap;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
+import static org.apache.hadoop.util.Shell.bashQuote;
+
 /**
  * A simple shell-based implementation of {@link IdMappingServiceProvider} 
  * Map id to user name or group name. It does update every 15 minutes. Only a
@@ -471,26 +473,27 @@ public class ShellBasedIdMapping implements IdMappingServiceProvider {
 
     boolean updated = false;
     updateStaticMapping();
+    String name2 = bashQuote(name);
 
     if (OS.startsWith("Linux") || OS.equals("SunOS") || OS.contains("BSD")) {
       if (isGrp) {
         updated = updateMapInternal(gidNameMap, "group",
-            getName2IdCmdNIX(name, true), ":",
+            getName2IdCmdNIX(name2, true), ":",
             staticMapping.gidMapping);
       } else {
         updated = updateMapInternal(uidNameMap, "user",
-            getName2IdCmdNIX(name, false), ":",
+            getName2IdCmdNIX(name2, false), ":",
             staticMapping.uidMapping);
       }
     } else {
       // Mac
       if (isGrp) {        
         updated = updateMapInternal(gidNameMap, "group",
-            getName2IdCmdMac(name, true), "\\s+",
+            getName2IdCmdMac(name2, true), "\\s+",
             staticMapping.gidMapping);
       } else {
         updated = updateMapInternal(uidNameMap, "user",
-            getName2IdCmdMac(name, false), "\\s+",
+            getName2IdCmdMac(name2, false), "\\s+",
             staticMapping.uidMapping);
       }
     }

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/util/Shell.java

@@ -145,7 +145,8 @@ public abstract class Shell {
    * @param arg the argument to quote
    * @return the quoted string
    */
-  static String bashQuote(String arg) {
+  @InterfaceAudience.Private
+  public static String bashQuote(String arg) {
     StringBuilder buffer = new StringBuilder(arg.length() + 2);
     buffer.append('\'')
         .append(arg.replace("'", "'\\''"))