Add nil pointer check to rule. (#181)

gcmurphy · web-flow · commit c6183b4d5c4c · 2018-02-28T04:29:25.000+10:00
TypeOf returns the type of expression e, or nil if not found. We are calling .String() on a value that may be nil in this clause. Relates to #174
diff --git a/rules/tls.go b/rules/tls.go
@@ -108,12 +108,15 @@ func (t *insecureConfigTLS) processTLSConfVal(n *ast.KeyValueExpr, c *gas.Contex
 }
 
 func (t *insecureConfigTLS) Match(n ast.Node, c *gas.Context) (*gas.Issue, error) {
-	if complit, ok := n.(*ast.CompositeLit); ok && complit.Type != nil && c.Info.TypeOf(complit.Type).String() == t.requiredType {
-		for _, elt := range complit.Elts {
-			if kve, ok := elt.(*ast.KeyValueExpr); ok {
-				issue := t.processTLSConfVal(kve, c)
-				if issue != nil {
-					return issue, nil
+	if complit, ok := n.(*ast.CompositeLit); ok && complit.Type != nil {
+		actualType := c.Info.TypeOf(complit.Type)
+		if actualType != nil && actualType.String() == t.requiredType {
+			for _, elt := range complit.Elts {
+				if kve, ok := elt.(*ast.KeyValueExpr); ok {
+					issue := t.processTLSConfVal(kve, c)
+					if issue != nil {
+						return issue, nil
+					}
 				}
 			}
 		}

Original file line number	Diff line number	Diff line change
`@@ -108,12 +108,15 @@ func (t insecureConfigTLS) processTLSConfVal(n ast.KeyValueExpr, c *gas.Contex`
`108`	`108`	`}`
`109`	`109`
`110`	`110`	`func (t insecureConfigTLS) Match(n ast.Node, c gas.Context) (*gas.Issue, error) {`
`111`		`- if complit, ok := n.(*ast.CompositeLit); ok && complit.Type != nil && c.Info.TypeOf(complit.Type).String() == t.requiredType {`
`112`		`- for _, elt := range complit.Elts {`
`113`		`- if kve, ok := elt.(*ast.KeyValueExpr); ok {`
`114`		`- issue := t.processTLSConfVal(kve, c)`
`115`		`- if issue != nil {`
`116`		`- return issue, nil`
	`111`	`+ if complit, ok := n.(*ast.CompositeLit); ok && complit.Type != nil {`
	`112`	`+ actualType := c.Info.TypeOf(complit.Type)`
	`113`	`+ if actualType != nil && actualType.String() == t.requiredType {`
	`114`	`+ for _, elt := range complit.Elts {`
	`115`	`+ if kve, ok := elt.(*ast.KeyValueExpr); ok {`
	`116`	`+ issue := t.processTLSConfVal(kve, c)`
	`117`	`+ if issue != nil {`
	`118`	`+ return issue, nil`
	`119`	`+ }`
`117`	`120`	`}`
`118`	`121`	`}`
`119`	`122`	`}`