[Pkg-netmeasure-discuss] Bug#887905: python-scapy: scapy.utils6.in6_ptop() fails on IPv6 addresses with more than one block of zeros

[Daniel Kahn Gillmor]

Package: python-scapy
Version: 2.3.3-3
Severity: normal

Consider the following example, based on the codepath in
arch/linux.py's read_routes6 (the example is compatible with both
python 2.7 and python3, so that i could test against python3-scapy):

----------------
import struct
import scapy.utils6
import codecs

f1 = b'20010db8000000010000000000000000'
print(f1)
f2 = struct.unpack('4s4s4s4s4s4s4s4s', f1)
print(f2)
f3= b':'.join(f2)
print(f3)
f4 = codecs.decode(f3)
print(f4)
f5 = scapy.utils6.in6_ptop(f4)
print(f5)
----------------

The final result should be:

2001:db8:0:1::

but it currently returns:

2001:db8::1::


which is not a valid IPv6 representation because there are two groups
of :: in the address.

fwiw, python3-scapy does not have the same problem; rather, it returns
the correct address.

      --dkg



-- System Information:
Debian Release: buster/sid
  APT prefers testing-debug
  APT policy: (500, 'testing-debug'), (500, 'testing'), (500, 'oldstable'), (200, 'unstable-debug'), (200, 'unstable'), (1, 'experimental-debug'), (1, 'experimental')
Architecture: amd64 (x86_64)
Foreign Architectures: i386

Kernel: Linux 4.14.0-2-amd64 (SMP w/4 CPU cores)
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8), LANGUAGE=en_US.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)

Versions of packages python-scapy depends on:
ii  python  2.7.14-4

python-scapy recommends no packages.

Versions of packages python-scapy suggests:
ii  ebtables                         2.0.10.4-3.5+b1
ii  graphviz                         2.38.0-18
pn  gv                               <none>
pn  hexer                            <none>
ii  imagemagick                      8:6.9.7.4+dfsg-16
ii  imagemagick-6.q16 [imagemagick]  8:6.9.7.4+dfsg-16
ii  librsvg2-bin                     2.40.20-2
ii  python-crypto                    2.6.1-8
pn  python-gnuplot                   <none>
ii  python-pcapy                     0.10.8-1+b1
pn  python-pyx                       <none>
ii  python-visual                    1:5.12-1.6+b6
ii  sox                              14.4.2-3
ii  tcpdump                          4.9.2-2
pn  tcpreplay                        <none>
ii  wireshark                        2.4.4-1
pn  xpdf                             <none>

-- no debconf information