From 971fdf7d1cc53601c594fc32461ee3f4c56145d8 Mon Sep 17 00:00:00 2001
From: Ed Catmur <ed@catmur.uk>
Date: Sat, 3 Feb 2018 17:33:20 +0000
Subject: [PATCH] Ignore (possibly malformed) options after EOL (#281)

---
 src/tcp.cpp            |  8 ++++++--
 tests/src/tcp_test.cpp | 13 ++++++++++++-
 2 files changed, 18 insertions(+), 3 deletions(-)

diff --git a/src/tcp.cpp b/src/tcp.cpp
index 67628d5..fb31884 100644
--- a/src/tcp.cpp
+++ b/src/tcp.cpp
@@ -81,7 +81,11 @@ TCP::TCP(const uint8_t* buffer, uint32_t total_sz) {
 
     while (stream.pointer() < header_end) {
         const OptionTypes option_type = (OptionTypes)stream.read<uint8_t>();
-        if (option_type <= NOP) {
+        if (option_type == EOL) {
+            stream.skip(header_end - stream.pointer());
+            break;
+        }
+        else if (option_type == NOP) {
             #if TINS_IS_CXX11
             add_option(option_type, 0);
             #else
@@ -309,7 +313,7 @@ void TCP::write_serialization(uint8_t* buffer, uint32_t total_sz) {
 
     if (options_size < total_options_size) {
         const uint16_t padding = total_options_size - options_size;
-        stream.fill(padding, 1);
+        stream.fill(padding, 0);
     }
 
     uint32_t check = 0;
diff --git a/tests/src/tcp_test.cpp b/tests/src/tcp_test.cpp
index 17ff227..4a6318d 100644
--- a/tests/src/tcp_test.cpp
+++ b/tests/src/tcp_test.cpp
@@ -13,7 +13,8 @@ using namespace Tins;
 class TCPTest : public testing::Test {
 public:
     static const uint8_t expected_packet[], checksum_packet[],
-                            partial_packet[];
+                            partial_packet[],
+                            malformed_option_after_eol_packet[];
     
     void test_equals(const TCP& tcp1, const TCP& tcp2);
 };
@@ -36,6 +37,11 @@ const uint8_t TCPTest::partial_packet[] = {
     142, 210, 0, 80, 60, 158, 102, 111, 10, 2, 46, 161, 80, 24, 0, 229, 247, 192, 0, 0
 };
 
+const uint8_t TCPTest::malformed_option_after_eol_packet[] = {
+    127, 77, 79, 29, 241, 218, 229, 70, 95, 174, 209, 35, 96, 2, 113,
+    218, 0, 0, 31, 174, 0, 1, 2, 4
+};
+
 
 TEST_F(TCPTest, DefaultConstructor) {
     TCP tcp;
@@ -271,6 +277,11 @@ TEST_F(TCPTest, SpoofedOptions) {
     EXPECT_EQ(pdu.serialize().size(), pdu.size());
 }
 
+TEST_F(TCPTest, MalformedOptionAfterEOL) {
+    TCP tcp(malformed_option_after_eol_packet, sizeof(malformed_option_after_eol_packet));
+    EXPECT_EQ(0U, tcp.options().size());
+}
+
 TEST_F(TCPTest, RemoveOption) {
     TCP tcp(22, 987);
     uint8_t a[] = { 1,2,3,4,5,6 };