Add buffer size checks to Net::Icmp

src/net-icmp.cpp

@@ -9,16 +9,18 @@
 namespace Net::Icmp
 {
 	//
-	// PacketHeader
+	// Header
 	//
-	PacketHeader::PacketHeader() {}
+	Header::Header() : type(static_cast<Type>(0)), code(0), checksum(0) {}
+	Header::Header(Type type, uint8_t code) : type(type), code(code), checksum(0) {}
 
-	PacketHeader::PacketHeader(Type type, uint8_t code) :
+	size_t Header::Serialize(uint8_t* buffer, const size_t bufferSize) const
-		type(type), code(code), checksum(0)
-	{}
-
-	size_t PacketHeader::Serialize(uint8_t* buffer) const
 	{
+		if (bufferSize < SerializedLength())
+		{
+			return 0;
+		}
+
 		size_t i = 0;
 		buffer[i++] = static_cast<uint8_t>(type);
 		buffer[i++] = code;
@@ -27,13 +29,18 @@ namespace Net::Icmp
 		return i;
 	}
 
-	PacketHeader PacketHeader::Deserialize(const uint8_t* buffer)
+	size_t Header::Deserialize(
+		Header& out, const uint8_t* buffer, const size_t bufferSize
+	) {
+		if (bufferSize < SerializedLength())
 		{
-		PacketHeader self;
+			return 0;
-		self.type = static_cast<Type>(buffer[0]);
+		}
-		self.code = buffer[1];
+
-		self.checksum = buffer[2] << 8 | buffer[3];
+		out.type = static_cast<Type>(buffer[0]);
-		return self;
+		out.code = buffer[1];
+		out.checksum = buffer[2] << 8 | buffer[3];
+		return 4;
 	}
 
 	//
@@ -43,8 +50,13 @@ namespace Net::Icmp
 	EchoHeader::EchoHeader(uint16_t identifier, uint16_t sequenceNumber) :
 		identifier(identifier), sequenceNumber(sequenceNumber) {}
 
-	size_t EchoHeader::Serialize(uint8_t* buffer) const
+	size_t EchoHeader::Serialize(uint8_t* buffer, const size_t bufferSize) const
 	{
+		if (bufferSize < SerializedLength())
+		{
+			return 0;
+		}
+
 		size_t i = 0;
 		buffer[i++] = identifier >> 8;
 		buffer[i++] = identifier;
@@ -53,20 +65,25 @@ namespace Net::Icmp
 		return i;
 	}
 
-	EchoHeader EchoHeader::Deserialize(const uint8_t* buffer)
+	size_t EchoHeader::Deserialize(
+		EchoHeader& out, const uint8_t* buffer, const size_t bufferSize
+	) {
+		if (bufferSize < SerializedLength())
 		{
-		EchoHeader self;
+			return 0;
-		self.identifier = buffer[0] << 8 | buffer[1];
+		}
-		self.sequenceNumber = buffer[2] << 8 | buffer[3];
+
-		return self;
+		out.identifier = buffer[0] << 8 | buffer[1];
+		out.sequenceNumber = buffer[2] << 8 | buffer[3];
+		return 4;
 	}
 
 	void SendEchoRequest(Utils::MacAddress mac, uint32_t ip)
 	{
-		Icmp::PacketHeader icmpHeader(Icmp::Type::EchoRequest, 0);
+		Icmp::Header icmpHeader(Icmp::Type::EchoRequest, 0);
 		Icmp::EchoHeader pingHeader(0, 0);
 
-		size_t ipv4TotalSize = Icmp::PacketHeader::SerializedLength() +
+		size_t ipv4TotalSize = Icmp::Header::SerializedLength() +
 			Icmp::EchoHeader::SerializedLength() +
 			Ipv4::Header::SerializedLength();
 		Ipv4::Header ipv4Header(
@@ -80,8 +97,8 @@ namespace Net::Icmp
 
 		size += ethernetHeader.Serialize(buffer + size, sizeof(buffer) - size);
 		size += ipv4Header.Serialize(buffer + size);
-		size += pingHeader.Serialize(buffer + size);
+		size += pingHeader.Serialize(buffer + size, sizeof(buffer) - size);
-		size += icmpHeader.Serialize(buffer + 1);
+		size += icmpHeader.Serialize(buffer + size, sizeof(buffer) - size);
 
 		const auto expectedSize =
 			ethernetHeader.SerializedLength() +
@@ -97,14 +114,17 @@ namespace Net::Icmp
 	static void handleEchoRequest(
 		const Ethernet::Header& reqEthernetHeader,
 		const Ipv4::Header& reqIpv4Header,
-		const Icmp::PacketHeader& reqIcmpHeader,
+		const Icmp::Header& reqIcmpHeader,
 		const uint8_t* reqBuffer,
 		const size_t reqBufferSize
 	) {
-		const auto reqEchoHeader = Icmp::EchoHeader::Deserialize(reqBuffer);
+		EchoHeader reqEchoHeader;
-		const auto reqHeaderSize = reqEchoHeader.SerializedLength();
+		const auto reqEchoHeaderSize =
+			Icmp::EchoHeader::Deserialize(reqEchoHeader, reqBuffer, reqBufferSize);
+		assert(reqEchoHeaderSize == reqEchoHeader.SerializedLength());
+		assert(reqEchoHeaderSize <= reqBufferSize);
 
-		const Icmp::PacketHeader respIcmpHeader(Icmp::Type::EchoReply, 0);
+		const Icmp::Header respIcmpHeader(Icmp::Type::EchoReply, 0);
 		const Ipv4::Header respIpv4Header(
 			Ipv4::Protocol::Icmp,
 			Utils::Ipv4Address,
@@ -117,11 +137,11 @@ namespace Net::Icmp
 			Ethernet::EtherType::Ipv4
 		);
 
-		const auto payloadLength =
+		const auto payloadSize =
 			reqIpv4Header.totalLength -
 			reqIpv4Header.SerializedLength() -
 			reqIcmpHeader.SerializedLength() -
-			reqEchoHeader.SerializedLength();
+			reqEchoHeaderSize;
 
 		std::array<uint8_t, USPI_FRAME_BUFFER_SIZE> respBuffer;
 
@@ -129,19 +149,20 @@ namespace Net::Icmp
 		respSize += respEthernetHeader.Serialize(
 			respBuffer.data() + respSize, respBuffer.size() - respSize);
 		respSize += respIpv4Header.Serialize(respBuffer.data() + respSize);
-		respSize += respIcmpHeader.Serialize(respBuffer.data() + respSize);
+		respSize += respIcmpHeader.Serialize(
+			respBuffer.data() + respSize, respBuffer.size() - respSize);
 		std::memcpy(
 			respBuffer.data() + respSize,
-			reqBuffer + reqHeaderSize,
+			reqBuffer + reqEchoHeaderSize,
-			payloadLength
+			payloadSize
 		);
-		respSize += payloadLength;
+		respSize += payloadSize;
 
 		const auto expectedRespSize =
 			respEthernetHeader.SerializedLength() +
 			respIpv4Header.SerializedLength() +
 			respIcmpHeader.SerializedLength() +
-			payloadLength;
+			payloadSize;
 		assert(respSize == expectedRespSize);
 		assert(respSize <= respBuffer.size());
 
@@ -160,8 +181,9 @@ namespace Net::Icmp
 		const auto ipv4Header = Ipv4::Header::Deserialize(buffer + headerSize);
 		headerSize += ipv4Header.SerializedLength();
 
-		const auto icmpHeader = Icmp::PacketHeader::Deserialize(buffer + headerSize);
+		Header icmpHeader;
-		headerSize += icmpHeader.SerializedLength();
+		headerSize += Icmp::Header::Deserialize(
+			icmpHeader, buffer + headerSize, bufferSize - headerSize);
 
 		const auto expectedHeaderSize =
 			ethernetHeader.SerializedLength() +

src/net-icmp.h

@@ -9,22 +9,23 @@ namespace Net::Icmp
 		EchoRequest = 8,
 	};
 
-	struct PacketHeader
+	struct Header
 	{
 		Type type;
 		uint8_t code;
 		uint16_t checksum;
 
-		PacketHeader();
+		Header();
-		PacketHeader(Type type, uint8_t code);
+		Header(Type type, uint8_t code);
 
 		constexpr static size_t SerializedLength()
 		{
 			return sizeof(type) + sizeof(code) + sizeof(checksum);
 		}
 
-		size_t Serialize(uint8_t* buffer) const;
+		size_t Serialize(uint8_t* buffer, const size_t bufferSize) const;
-		static PacketHeader Deserialize(const uint8_t* buffer);
+		static size_t Deserialize(
+			Header& out, const uint8_t* buffer, const size_t bufferSize);
 	};
 
 	struct EchoHeader
@@ -40,10 +41,11 @@ namespace Net::Icmp
 			return sizeof(identifier) + sizeof(sequenceNumber);
 		}
 
-		size_t Serialize(uint8_t* buffer) const;
+		size_t Serialize(uint8_t* buffer, const size_t bufferSize) const;
-		static EchoHeader Deserialize(const uint8_t* buffer);
+		static size_t Deserialize(
+			EchoHeader& out, const uint8_t* buffer, const size_t bufferSize);
 	};
 
-	void SendEchoRequest(Utils::MacAddress mac, uint32_t ip);
+	void SendEchoRequest(const Utils::MacAddress mac, const uint32_t ip);
 	void HandlePacket(const uint8_t* buffer, const size_t bufferSize);
 } // namespace Net::Icmp