Bump gopkg.in/yaml.v2 from 2.2.3 to 2.2.4

Bumps [gopkg.in/yaml.v2](https://github.com/go-yaml/yaml) from 2.2.3 to 2.2.4.
- [Release notes](https://github.com/go-yaml/yaml/releases)
- [Commits](https://github.com/go-yaml/yaml/compare/v2.2.3...v2.2.4)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>
Signed-off-by: Valentin Rothberg <rothberg@redhat.com>

3 files changed, 43 insertions, 2 deletions

diff --git a/vendor/gopkg.in/yaml.v2/decode.go b/vendor/gopkg.in/yaml.v2/decode.go
index 91679b5b4..531087655 100644
--- a/vendor/gopkg.in/yaml.v2/decode.go
+++ b/vendor/gopkg.in/yaml.v2/decode.go
@@ -318,12 +318,37 @@ func (d *decoder) prepare(n *node, out reflect.Value) (newout reflect.Value, unm
 	return out, false, false
 }
 
+const (
+	// 400,000 decode operations is ~500kb of dense object declarations, or ~5kb of dense object declarations with 10000% alias expansion
+	alias_ratio_range_low = 400000
+	// 4,000,000 decode operations is ~5MB of dense object declarations, or ~4.5MB of dense object declarations with 10% alias expansion
+	alias_ratio_range_high = 4000000
+	// alias_ratio_range is the range over which we scale allowed alias ratios
+	alias_ratio_range = float64(alias_ratio_range_high - alias_ratio_range_low)
+)
+
+func allowedAliasRatio(decodeCount int) float64 {
+	switch {
+	case decodeCount <= alias_ratio_range_low:
+		// allow 99% to come from alias expansion for small-to-medium documents
+		return 0.99
+	case decodeCount >= alias_ratio_range_high:
+		// allow 10% to come from alias expansion for very large documents
+		return 0.10
+	default:
+		// scale smoothly from 99% down to 10% over the range.
+		// this maps to 396,000 - 400,000 allowed alias-driven decodes over the range.
+		// 400,000 decode operations is ~100MB of allocations in worst-case scenarios (single-item maps).
+		return 0.99 - 0.89*(float64(decodeCount-alias_ratio_range_low)/alias_ratio_range)
+	}
+}
+
 func (d *decoder) unmarshal(n *node, out reflect.Value) (good bool) {
 	d.decodeCount++
 	if d.aliasDepth > 0 {
 		d.aliasCount++
 	}
-	if d.aliasCount > 100 && d.decodeCount > 1000 && float64(d.aliasCount)/float64(d.decodeCount) > 0.99 {
+	if d.aliasCount > 100 && d.decodeCount > 1000 && float64(d.aliasCount)/float64(d.decodeCount) > allowedAliasRatio(d.decodeCount) {
 		failf("document contains excessive aliasing")
 	}
 	switch n.kind {
diff --git a/vendor/gopkg.in/yaml.v2/scannerc.go b/vendor/gopkg.in/yaml.v2/scannerc.go
index 077fd1dd2..570b8ecd1 100644
--- a/vendor/gopkg.in/yaml.v2/scannerc.go
+++ b/vendor/gopkg.in/yaml.v2/scannerc.go
@@ -906,6 +906,9 @@ func yaml_parser_remove_simple_key(parser *yaml_parser_t) bool {
 	return true
 }
 
+// max_flow_level limits the flow_level
+const max_flow_level = 10000
+
 // Increase the flow level and resize the simple key list if needed.
 func yaml_parser_increase_flow_level(parser *yaml_parser_t) bool {
 	// Reset the simple key on the next level.
@@ -913,6 +916,11 @@ func yaml_parser_increase_flow_level(parser *yaml_parser_t) bool {
 
 	// Increase the flow level.
 	parser.flow_level++
+	if parser.flow_level > max_flow_level {
+		return yaml_parser_set_scanner_error(parser,
+			"while increasing flow level", parser.simple_keys[len(parser.simple_keys)-1].mark,
+			fmt.Sprintf("exceeded max depth of %d", max_flow_level))
+	}
 	return true
 }
 
@@ -925,6 +933,9 @@ func yaml_parser_decrease_flow_level(parser *yaml_parser_t) bool {
 	return true
 }
 
+// max_indents limits the indents stack size
+const max_indents = 10000
+
 // Push the current indentation level to the stack and set the new level
 // the current column is greater than the indentation level.  In this case,
 // append or insert the specified token into the token queue.
@@ -939,6 +950,11 @@ func yaml_parser_roll_indent(parser *yaml_parser_t, column, number int, typ yaml
 		// indentation level.
 		parser.indents = append(parser.indents, parser.indent)
 		parser.indent = column
+		if len(parser.indents) > max_indents {
+			return yaml_parser_set_scanner_error(parser,
+				"while increasing indent level", parser.simple_keys[len(parser.simple_keys)-1].mark,
+				fmt.Sprintf("exceeded max depth of %d", max_indents))
+		}
 
 		// Create a token and insert it into the queue.
 		token := yaml_token_t{
diff --git a/vendor/modules.txt b/vendor/modules.txt
index 1d92a249d..68106f3d8 100644
--- a/vendor/modules.txt
+++ b/vendor/modules.txt
@@ -549,7 +549,7 @@ gopkg.in/fsnotify.v1
 gopkg.in/inf.v0
 # gopkg.in/tomb.v1 v1.0.0-20141024135613-dd632973f1e7
 gopkg.in/tomb.v1
-# gopkg.in/yaml.v2 v2.2.3
+# gopkg.in/yaml.v2 v2.2.4
 gopkg.in/yaml.v2
 # k8s.io/api v0.0.0-20190813020757-36bff7324fb7
 k8s.io/api/core/v1