Remove redundant check length check

Add tests to cover all length check cases
bi-zone · May 23, 2024 · b7da01d · b7da01d
1 parent b9b61df
commit b7da01d
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Showing 2 changed files with 12 additions and 13 deletions.
diff --git a/ber.go b/ber.go
@@ -106,12 +106,12 @@ func lengthLength(i int) (numBytes int) {
 // added to 0x80. The length is encoded in big endian encoding follow after
 //
 // Examples:
-//  length | byte 1 | bytes n
-//  0      | 0x00   | -
-//  120    | 0x78   | -
-//  200    | 0x81   | 0xC8
-//  500    | 0x82   | 0x01 0xF4
 //
+//	length | byte 1 | bytes n
+//	0      | 0x00   | -
+//	120    | 0x78   | -
+//	200    | 0x81   | 0xC8
+//	500    | 0x82   | 0x01 0xF4
 func encodeLength(out *bytes.Buffer, length int) (err error) {
 	if length >= 128 {
 		l := lengthLength(length)
@@ -134,9 +134,6 @@ func encodeLength(out *bytes.Buffer, length int) (err error) {
 
 func readObject(ber []byte, offset int) (asn1Object, int, error) {
 	berLen := len(ber)
-	if offset >= berLen {
-		return nil, 0, errors.New("ber2der: offset is after end of ber data")
-	}
 	tagStart := offset
 	b := ber[offset]
 	offset++
@@ -259,7 +256,7 @@ func readObject(ber []byte, offset int) (asn1Object, int, error) {
 }
 
 func isIndefiniteTermination(ber []byte, offset int) (bool, error) {
-	if len(ber) - offset < 2 {
+	if len(ber)-offset < 2 {
 		return false, errors.New("ber2der: Invalid BER format")
 	}
 

diff --git a/ber_test.go b/ber_test.go
@@ -44,14 +44,16 @@ func TestBer2Der_Negatives(t *testing.T) {
 		Input         []byte
 		ErrorContains string
 	}{
-		{[]byte{0x30, 0x85}, "end of ber data reached"},
+		{[]byte{0x1f, 0x0}, "end of ber data reached"},
+		{[]byte{0x30, 0x85, 0x1}, "tag length too long"},
 		{[]byte{0x30, 0x84, 0x80, 0x0, 0x0, 0x0}, "length is negative"},
 		{[]byte{0x30, 0x82, 0x0, 0x1}, "length has leading zero"},
+		{[]byte{0x30, 0x81, 0x01}, "end of ber data reached"},
 		{[]byte{0x30, 0x80, 0x1, 0x2, 0x1, 0x2}, "Invalid BER format"},
-		{[]byte{0x30, 0x80, 0x1, 0x2}, "end of ber data reached"},
-		{[]byte{0x30, 0x03, 0x01, 0x02}, "length is more than available data"},
+		{[]byte{0x30, 0x80, 0x1, 0x2, 0x1}, "BER tag length is more than available data"},
+		{[]byte{0x1f, 0x80}, "end of ber data reached"},
+		{[]byte{0x30, 0x80}, "end of ber data reached"},
 		{[]byte{0x30}, "end of ber data reached"},
-		{[]byte("0 0 0 0 0 0 0 0\x020\x020\x020\x020\x020\x020\x020\x020\x020\x020\x020\x020\x020\x020\x02\x1f0"), "end of ber data reached"},
 	}
 
 	for _, fixture := range fixtures {