Implemented better testing and fixed skipepd frames

Common/Client/go/udpsprotocol/protocol.go

@@ -127,7 +127,12 @@ func (s SignalInfo) NumElements() int {
 	if c == 0 {
 		c = 1
 	}
-	return r * c
+	/* HI-2: cap at 1M to prevent integer overflow / OOM from crafted packets */
+	n := r * c
+	if n < 0 || n > 1024*1024 {
+		return 1024 * 1024
+	}
+	return n
 }
 
 // rawTypeSize returns the byte size for one element of the raw (unquantised) type.
@@ -227,6 +232,11 @@ func ParseConfig(payload []byte) ([]SignalInfo, uint8, error) {
 		return nil, 0, fmt.Errorf("config payload too short")
 	}
 	numSigs := binary.LittleEndian.Uint32(payload[0:4])
+	/* HI-2: validate numSigs against payload length before allocating */
+	maxSigs := uint32(len(payload) / SigDescSize)
+	if numSigs > maxSigs {
+		return nil, 0, fmt.Errorf("config claims %d signals but payload can hold at most %d", numSigs, maxSigs)
+	}
 	offset := 4
 	sigs := make([]SignalInfo, 0, numSigs)
 	for i := uint32(0); i < numSigs; i++ {
@@ -327,6 +337,10 @@ func ParseData(payload []byte, sigs []SignalInfo, publishMode uint8, arrivalTime
 		if numSamples == 0 {
 			return []DataSample{}, nil
 		}
+		/* HI-2: sanity-cap numSamples to prevent OOM from crafted packets */
+		if numSamples < 0 || numSamples > 1024*1024 {
+			return nil, fmt.Errorf("accumulate numSamples %d out of range", numSamples)
+		}
 
 		// Parse per-signal data blocks (all slots for a signal are contiguous).
 		accumVals := make(map[string][]float64, len(sigs)) // scalars: numSamples values