Updating index handling

Signed-off-by: Matt Farina <matt@mattfarina.com>
(cherry picked from commit 225f8d7732)

pkg/strvals/parser.go

@@ -29,6 +29,10 @@ import (
 // ErrNotList indicates that a non-list was treated as a list.
 var ErrNotList = errors.New("not a list")
 
+// MaxIndex is the maximum index that will be allowed by setIndex.
+// The default value 65536 = 1024 * 64
+var MaxIndex = 65536
+
 // ToYAML takes a string of arguments and converts to a YAML document.
 func ToYAML(s string) (string, error) {
 	m, err := Parse(s)
@@ -249,6 +253,9 @@ func setIndex(list []interface{}, index int, val interface{}) (l2 []interface{},
 	if index < 0 {
 		return list, fmt.Errorf("negative %d index not allowed", index)
 	}
+	if index > MaxIndex {
+		return list, fmt.Errorf("index of %d is greater than maximum supported index of %d", index, MaxIndex)
+	}
 	if len(list) <= index {
 		newlist := make([]interface{}, index+1)
 		copy(newlist, list)

pkg/strvals/parser_test.go

@@ -62,6 +62,14 @@ func TestSetIndex(t *testing.T) {
 			val:     4,
 			err:     true,
 		},
+		{
+			name:    "large",
+			initial: []interface{}{0, 1, 2, 3, 4, 5},
+			expect:  []interface{}{0, 1, 2, 3, 4, 5},
+			add:     MaxIndex + 1,
+			val:     4,
+			err:     true,
+		},
 	}
 
 	for _, tt := range tests {