panic when dumping some RadioTap packets #113
Description
Overview
I have been capturing some Wifi traffic in monitor mode, and came across a panic when calling the String() method on the Packet interface for some packets. I managed to capture the bytes of an offending packet and created a very small reproduction program below.
The panic message that I get says:
panic: value method github.com/gopacket/gopacket/layers.Dot11CodingType.String called using nil *Dot11CodingType pointer
It is fine if this is not a valid packet, but it would be nice if it showed up as a decode error of some sort. I'm not entirely sure what the cause for this is, as I'm not expert here (yet), but I can look into it more as this happens fairly regularly for me.
Reproduction
package main
import (
"log/slog"
"github.com/gopacket/gopacket"
"github.com/gopacket/gopacket/layers"
)
func main() {
pkt := []byte{
0, 0, 48, 0, 46, 64, 64, 160, 32, 8, 0, 160, 32, 8, 0, 0, 80,
12, 133, 9, 192, 0, 175, 0, 0, 0, 0, 0, 0, 0, 0, 0, 51, 229,
109, 1, 0, 0, 0, 0, 22, 0, 17, 3, 175, 0, 173, 1, 96, 204, 167,
242, 184, 15, 207, 1, 120, 226, 240, 116, 33, 39, 49, 116, 91,
202, 181, 58, 126, 72, 77, 133, 213, 10, 90, 22, 99, 122, 120,
218, 169, 221, 207, 134, 235, 30, 124, 156, 34, 64, 153, 155,
142, 1, 165, 5, 57, 219, 78, 116, 237, 169, 46, 91, 133, 242,
215, 171, 31, 153, 93, 222, 93, 58, 174, 1, 178, 184, 65, 188,
152, 119, 217, 172, 145, 75, 215, 101, 100, 95, 212, 60, 32, 30,
129, 46, 223, 158, 65, 61, 21, 176, 161, 34, 198, 164, 116, 94,
124, 200, 190, 65, 121, 178, 129, 12, 153, 191, 180, 57, 101, 218,
25, 102, 30, 250, 25, 142, 108, 162, 112, 122, 194, 246, 229, 238,
157, 215, 188, 186, 31, 27, 40, 80, 4, 149, 56, 75, 167, 39, 51, 52,
143, 175, 213, 196, 227, 5, 38, 234, 143, 89, 122, 201, 245, 26, 102,
41, 169, 151, 0, 46, 3, 159, 22, 137, 168, 211, 76, 133, 161, 174, 212,
67, 162, 203, 15, 58, 123, 55, 136, 156, 82, 121, 238, 249, 96, 53,
226, 231, 140, 79, 19, 226, 124, 145, 217, 218, 31, 70, 167, 219, 199,
124, 249, 232, 152, 176, 144, 169, 90, 26, 154, 175, 247, 161, 121,
183, 167, 248, 242, 152, 36, 254, 203, 176, 13, 126, 149, 223, 252,
141, 64, 92, 183,
}
parsed := gopacket.NewPacket(pkt, layers.LayerTypeRadioTap, gopacket.DecodeOptions{Lazy: false, DecodeStreamsAsDatagrams: true})
slog.Info(parsed.String())
}