Fix Unknown read in pcpp::NflogLayer::parseNextLayer

Common++/header/GeneralUtils.h

@@ -50,6 +50,21 @@ namespace pcpp
 	 * @return A pointer to the beginning of the substring, or NULL if the substring is not found
 	 */
 	char* cross_platform_memmem(const char* haystack, size_t haystackLen, const char* needle, size_t needleLen);
+
+	/**
+	 * Calculates alignment.
+	 * @param[in] number Given number
+	 * @return The aligned number
+	*/
+	template <int alignment>
+	static int align(int number)
+	{
+		// Only works for alignment with power of 2
+		constexpr bool isPowerOfTwo = alignment && ((alignment & (alignment - 1)) == 0);
+		static_assert(isPowerOfTwo, "Alignment must be a power of 2");
+		int mask = alignment - 1;
+		return (number + mask) & ~mask;
+	}
 }
 
 #endif // PCAPPP_GENERAL_UTILS

Packet++/header/NflogLayer.h

@@ -3,6 +3,7 @@
 
 #include "Layer.h"
 #include "TLVData.h"
+#include "GeneralUtils.h"
 
 /// @file
 
@@ -101,23 +102,19 @@ namespace pcpp
 		/**
 		 * @return recordLen attribute in NflogTLVRawData
 		 */
-		size_t getTotalSize() const { return m_Data->recordLen; }
+		size_t getTotalSize() const
+		{
+			// as in https://github.com/the-tcpdump-group/libpcap/blob/766b607d60d8038087b49fc4cf433dac3dcdb49c/pcap-util.c#L371-L374
+			return align<4>(m_Data->recordLen);
+		}
 
 		/**
 		 * Assign a pointer to the TLV record raw data (byte array)
 		 * @param[in] recordRawData A pointer to the TLV record raw data
 		 */
 		void assign(uint8_t* recordRawData)
 		{
-			if(recordRawData == nullptr)
-				m_Data = nullptr;
-			else
-			{
-				// to pass from some unknown paddings after tlv with type NFULA_PREFIX
-				while (*recordRawData == 0)
-					recordRawData += 1;
-				m_Data = (NflogTLVRawData*)recordRawData;
-			}
+			m_Data = (NflogTLVRawData*)recordRawData;
 		}
 
 		/**

Tests/Packet++Test/Tests/NflogTests.cpp

@@ -38,14 +38,14 @@ PTF_TEST_CASE(NflogPacketParsingTest)
 		pcpp::NflogTlvType::NFULA_PAYLOAD
 	};
 
-	int optSizes[6] = {8, 5, 8, 8, 8, 65};
+	int optSizes[6] = {8, 8, 8, 8, 8, 68};
 	std::string optDataAsHexString[6] = {
 		"0800010000000300",
-		"05000a0000",
+		"05000a0000000000",
 		"0800050000000002",
 		"08000b0000000000",
 		"08000e0000000000",
-		"410009004500003d021040004011208f0a00020f0a000203a542003500294156c04e0100000100000000000003777777076578616d706c65036e65740000010001"
+		"410009004500003d021040004011208f0a00020f0a000203a542003500294156c04e0100000100000000000003777777076578616d706c65036e657400000100012f0a31"
 	};
 
 	for (int i = 0; i < 6; i++) {
@@ -56,5 +56,5 @@ PTF_TEST_CASE(NflogPacketParsingTest)
 	}
 
 	/// sum of all TLVs before payload + size of nflog_header + size of (recordLength + recordType) variables of payload TLV
-	PTF_ASSERT_EQUAL(nflogLayer->getHeaderLen(), 45);
+	PTF_ASSERT_EQUAL(nflogLayer->getHeaderLen(), 48);
 }