Address new coverity scan issues

New defect(s) Reported-by: Coverity Scan
Showing 3 of 3 defect(s)

• • CID 1361684: Null pointer dereferences (NULL_RETURNS)
    /gateway-provider-security-shiro/src/main/java/org/apache/hadoop/gateway/shirorealm/KnoxPamRealm.java: 140 in org.apache.hadoop.gateway.shirorealm.KnoxPamRealm.doGetAuthenticationInfo(org.apache.shiro.authc.AuthenticationToken)()

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• • • CID 1361684: Null pointer dereferences (NULL_RETURNS)
      /gateway-provider-security-shiro/src/main/java/org/apache/hadoop/gateway/shirorealm/KnoxPamRealm.java: 140 in org.apache.hadoop.gateway.shirorealm.KnoxPamRealm.doGetAuthenticationInfo(org.apache.shiro.authc.AuthenticationToken)()
      134 ShiroLog.failedLoginAttempt(e.getCause());
      135 throw new AuthenticationException(e);
      136 }
      137 HashRequest.Builder builder = new HashRequest.Builder();
      138 Hash credentialsHash = hashService
      139 .computeHash(builder.setSource(token.getCredentials()).setAlgorithmName(HASHING_ALGORITHM).build());
      >>> CID 1361684: Null pointer dereferences (NULL_RETURNS)
      >>> Calling a method on null object "credentialsHash".
      140 return new SimpleAuthenticationInfo(new UnixUserPrincipal(user) , credentialsHash.toHex(), credentialsHash.getSalt(),
      141 getName());
      142 }
      143

• • CID 1361683: Null pointer dereferences (NULL_RETURNS)
    /gateway-provider-security-shiro/src/main/java/org/apache/hadoop/gateway/filter/ShiroSubjectIdentityAdapter.java: 71 in org.apache.hadoop.gateway.filter.ShiroSubjectIdentityAdapter.doFilter(javax.servlet.ServletRequest, javax.servlet.ServletResponse, javax.servlet.FilterChain)()

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• • • CID 1361683: Null pointer dereferences (NULL_RETURNS)
      /gateway-provider-security-shiro/src/main/java/org/apache/hadoop/gateway/filter/ShiroSubjectIdentityAdapter.java: 71 in org.apache.hadoop.gateway.filter.ShiroSubjectIdentityAdapter.doFilter(javax.servlet.ServletRequest, javax.servlet.ServletResponse, javax.servlet.FilterChain)()
      65 Subject subject = SecurityUtils.getSubject();
      66
      67 // trigger call to shiro authorization realm
      68 // we use shiro authorization realm to look up groups
      69 subject.hasRole("authenticatedUser");
      70
      >>> CID 1361683: Null pointer dereferences (NULL_RETURNS)
      >>> Calling a method on null object "subject.getPrincipal()".
      71 final String principalName = (String) subject.getPrincipal().toString();
      72
      73 CallableChain callableChain = new CallableChain(request, response, chain);
      74 SecurityUtils.getSubject().execute(callableChain);
      75 }
      76

• • CID 1361682: Null pointer dereferences (FORWARD_NULL)
    /gateway-provider-security-shiro/src/main/java/org/apache/hadoop/gateway/shirorealm/KnoxPamRealm.java: 119 in org.apache.hadoop.gateway.shirorealm.KnoxPamRealm.doGetAuthorizationInfo(org.apache.shiro.subject.PrincipalCollection)()

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• • • CID 1361682: Null pointer dereferences (FORWARD_NULL)
      /gateway-provider-security-shiro/src/main/java/org/apache/hadoop/gateway/shirorealm/KnoxPamRealm.java: 119 in org.apache.hadoop.gateway.shirorealm.KnoxPamRealm.doGetAuthorizationInfo(org.apache.shiro.subject.PrincipalCollection)()
      113 UnixUserPrincipal user = principals.oneByType(UnixUserPrincipal.class);
      114 if (user != null) { 115 roles.addAll(user.getUnixUser().getGroups()); 116 }

      117 SecurityUtils.getSubject().getSession().setAttribute(SUBJECT_USER_ROLES, roles);
      118 SecurityUtils.getSubject().getSession().setAttribute(SUBJECT_USER_GROUPS, roles);
      >>> CID 1361682: Null pointer dereferences (FORWARD_NULL)
      >>> Calling a method on null object "user".
      119 GatewayLog.lookedUpUserRoles(roles, user.getName());
      120 return new SimpleAuthorizationInfo(roles);
      121 }
      122
      123 @Override
      124 protected AuthenticationInfo doGetAuthenticationInfo(AuthenticationToken token) throws AuthenticationException {