Add support for multiple admins (#8487)

Also define IAM policies for administering
MinIO server

pkg/iam/policy/statement_test.go

@@ -183,6 +183,14 @@ func TestStatementIsValid(t *testing.T) {
 		t.Fatalf("unexpected error. %v\n", err)
 	}
 
+	func3, err := condition.NewStringEqualsFunc(
+		condition.AWSUserAgent,
+		"NSPlayer",
+	)
+	if err != nil {
+		t.Fatalf("unexpected error. %v\n", err)
+	}
+
 	testCases := []struct {
 		statement Statement
 		expectErr bool
@@ -233,6 +241,18 @@ func TestStatementIsValid(t *testing.T) {
 			NewResourceSet(NewResource("mybucket", "myobject*")),
 			condition.NewFunctions(func1),
 		), false},
+		{NewStatement(
+			policy.Allow,
+			NewActionSet(CreateUserAdminAction, DeleteUserAdminAction),
+			nil,
+			condition.NewFunctions(func2, func3),
+		), true},
+		{NewStatement(
+			policy.Allow,
+			NewActionSet(CreateUserAdminAction, DeleteUserAdminAction),
+			nil,
+			condition.NewFunctions(),
+		), false},
 	}
 
 	for i, testCase := range testCases {