Exception when calling sniff for multiple interfaces

[hobobandy]

Brief description

Basic sniff capture using multiple interfaces.
When passing a list (or dict) of interfaces, Scapy raises an exception (see below).

See 'Related resources' for probable cause/fix.

Environment

Scapy version: 2.4.5
Python version: 3.8.5
Operation System: Ubuntu 20.04.2.0 Desktop

How to reproduce

packets = sniff(iface=["wlan0", "wlan1", "wlan2", "wlan3"], prn=callback, store=0)

Actual result

File "scapy_file.py", line 197, in run
packets = sniff(iface=["wlan0","wlan1","wlan2","wlan3"], prn=callback, store=0)
File "/root/.local/share/virtualenvs/myenv/lib/python3.8/site-packages/scapy/sendrecv.py", line 1264, in sniff
sniffer._run(*args, **kwargs)
File "/root/.local/share/virtualenvs/myenv/lib/python3.8/site-packages/scapy/sendrecv.py", line 1128, in _run
sniff_sockets[L2socket(type=ETH_P_ALL, iface=iface,
File "/root/.local/share/virtualenvs/myenv/lib/python3.8/site-packages/scapy/arch/linux.py", line 501, in init
set_promisc(self.ins, self.iface)
File "/root/.local/share/virtualenvs/myenv/lib/python3.8/site-packages/scapy/arch/linux.py", line 181, in set_promisc
mreq = struct.pack("IHH8s", get_if_index(iff), PACKET_MR_PROMISC, 0, b"")
File "/root/.local/share/virtualenvs/myenv/lib/python3.8/site-packages/scapy/arch/linux.py", line 401, in get_if_index
return int(struct.unpack("I", get_if(iff, SIOCGIFINDEX)[16:20])[0])
File "/root/.local/share/virtualenvs/myenv/lib/python3.8/site-packages/scapy/arch/common.py", line 65, in get_if
return ioctl(sck, cmd, struct.pack("16s16x", iff.encode("utf8")))
AttributeError: 'list' object has no attribute 'encode'

Expected result

Expecting sniff to begin.

Related resources

Source probably related to this issue:
sendrecv.py - line 1111 to line 1128

Since I don't use a custom L2 socket, I simply commented out line 1111 to 1113 and used the default L2 socket:
L2socket = conf.L2listen

Proper fix probably involves looping through list items to instance an L2socket.

[guedou]

Thanks for reporting the issue. That is indeed a regression!

[guedou]

This regression was introduced in 4521d8a