zigbee: fix ZCLPricePublishPrice rate_label dissection

scapy/layers/zigbee.py

@@ -1318,12 +1318,24 @@ class ZCLPriceGetScheduledPrices(Packet):
     ]
 
 
+class _RateLabelStrField(StrLenField):
+    """Rate Label is a UTF-8 encoded octet string whose first octet indicates
+    the length of the label; the value includes the length octet."""
+
+    def getfield(self, pkt, s):
+        if not s:
+            return s, ""
+        length = s[0] if isinstance(s[0], int) else ord(s[0])
+        self.length_from = lambda x: length + 1
+        return StrLenField.getfield(self, pkt, s)
+
+
 class ZCLPricePublishPrice(Packet):
     name = "Price Cluster: Publish Price Command (Server: Generated)"
     fields_desc = [
         XLEIntField("provider_id", 0x00000000),  # Unsigned 32-bit Integer (4 octets)  # noqa: E501
         # Rate Label is a UTF-8 encoded Octet String (0-12 octets). The first Octet indicates the length.  # noqa: E501
-        StrLenField("rate_label", "", length_from=lambda pkt:int(pkt.rate_label[0])),  # TODO verify  # noqa: E501
+        _RateLabelStrField("rate_label", ""),
         XLEIntField("issuer_event_id", 0x00000000),  # Unsigned 32-bit Integer (4 octets)  # noqa: E501
         XLEIntField("current_time", 0x00000000),  # UTCTime (4 octets)
         ByteField("unit_of_measure", 0),  # 8 bits enumeration (1 octet)

test/scapy/layers/dot15d4.uts

@@ -948,3 +948,17 @@ assert ZCLIASZoneZoneEnrollResponse in pkt.layers()
 assert pkt[ZCLIASZoneZoneEnrollResponse].rsp_code == 0x00
 assert pkt[ZCLIASZoneZoneEnrollResponse].zone_id == 0x3a
 assert raw(pkt[ZCLIASZoneZoneEnrollResponse].payload) == b''
+
+= ZCLPricePublishPrice rate label dissection
+
+p = ZCLPricePublishPrice(bytes.fromhex("1122334404616263645566778899aabbcc01ccdd0203445566778899aabbccdd112233445566778899aabbccddee"))
+assert p.provider_id == 0x44332211
+assert p.rate_label == b"\x04abcd"
+assert p.issuer_event_id == 0x88776655
+assert p.current_time == 0xCCBBAA99
+assert p.price == 0xDDCCBBAA
+assert p.price_ratio == 0x11
+assert p.generation_price == 0x55443322
+assert p.number_of_block_thresholds == 0xDD
+assert p.price_control == 0xEE
+assert raw(p) == bytes.fromhex("1122334404616263645566778899aabbcc01ccdd0203445566778899aabbccdd112233445566778899aabbccddee")