From 186871d2a9b95ae61baecde8c8ec901ba2b96dba Mon Sep 17 00:00:00 2001
From: Miek Gieben <miek@miek.nl>
Date: Thu, 5 Dec 2013 09:54:46 +0000
Subject: [PATCH] Add check for > maxUint16 sizes TYPEXXXX or CLASSXXX

These were silently wrapped in a uint16, nicer to actually give
an error.
---
 parse_test.go | 19 ++++++++++++-------
 zscan.go      |  5 +++--
 2 files changed, 15 insertions(+), 9 deletions(-)

diff --git a/parse_test.go b/parse_test.go
index 0c89e85d..d4816c0e 100644
--- a/parse_test.go
+++ b/parse_test.go
@@ -741,15 +741,20 @@ func TestTXT(t *testing.T) {
 }
 
 func TestRR(t *testing.T) {
-	rr, err := NewRR("example.com IN TYPE1234 \\# 4 aabbccdd")
-	if err == nil {
-		t.Logf("%s\n", rr.String())
-	} else {
-		t.Error("Failed to parse TYPE1234 RR: ", err.Error())
+	_, err := NewRR("example.com IN TYPE1234 \\# 4 aabbccdd")
+	if err != nil {
+		t.Logf("Failed to parse TYPE1234 RR: ", err.Error())
+		t.Fail()
 	}
-	rr, err = NewRR("example.com IN TYPE1 \\# 4 0a000001")
+	_, err = NewRR("example.com IN TYPE655341 \\# 8 aabbccddaabbccdd")
 	if err == nil {
-		t.Error("This should not work")
+		t.Logf("This should not work, for TYPE655341")
+		t.Fail()
+	}
+	_, err = NewRR("example.com IN TYPE1 \\# 4 0a000001")
+	if err == nil {
+		t.Logf("This should not work")
+		t.Fail()
 	}
 }
 
diff --git a/zscan.go b/zscan.go
index 109d0fd7..fd4ecc1c 100644
--- a/zscan.go
+++ b/zscan.go
@@ -23,6 +23,7 @@ func (d debugging) Printf(format string, args ...interface{}) {
 }
 
 const maxTok = 2048 // Largest token we can return.
+const maxUint16 = 1<<16 - 1
 
 // Tokinize a RFC 1035 zone file. The tokenizer will normalize it:
 // * Add ownernames if they are left blank;
@@ -789,7 +790,7 @@ func zlexer(s *scan, c chan lex) {
 // Extract the class number from CLASSxx
 func classToInt(token string) (uint16, bool) {
 	class, ok := strconv.Atoi(token[5:])
-	if ok != nil {
+	if ok != nil || class > maxUint16 {
 		return 0, false
 	}
 	return uint16(class), true
@@ -798,7 +799,7 @@ func classToInt(token string) (uint16, bool) {
 // Extract the rr number from TYPExxx
 func typeToInt(token string) (uint16, bool) {
 	typ, ok := strconv.Atoi(token[4:])
-	if ok != nil {
+	if ok != nil || typ > maxUint16 {
 		return 0, false
 	}
 	return uint16(typ), true