ipaddress module takes bytes input as valid ip address

[philipbond]

BPO	43769
Nosy	@vstinner, @ericvsmith, @ezio-melotti
Files	cidr-gen.py: To generate Cidr rules from inputted hosst/ips

^{Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.}

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GitHub fields:

assignee = None
closed_at = <Date 2021-04-07.21:33:21.884>
created_at = <Date 2021-04-07.21:24:15.840>
labels = ['invalid', 'type-bug', 'library']
title = 'ipaddress module takes bytes input as valid ip address'
updated_at = <Date 2021-04-07.22:06:05.710>
user = 'https://bugs.python.org/philipbond'

bugs.python.org fields:

activity = <Date 2021-04-07.22:06:05.710>
actor = 'philip.bond'
assignee = 'none'
closed = True
closed_date = <Date 2021-04-07.21:33:21.884>
closer = 'eric.smith'
components = ['Library (Lib)']
creation = <Date 2021-04-07.21:24:15.840>
creator = 'philip.bond'
dependencies = []
files = ['49940']
hgrepos = []
issue_num = 43769
keywords = []
message_count = 5.0
messages = ['390478', '390480', '390481', '390482', '390487']
nosy_count = 4.0
nosy_names = ['vstinner', 'eric.smith', 'ezio.melotti', 'philip.bond']
pr_nums = []
priority = 'normal'
resolution = 'not a bug'
stage = 'resolved'
status = 'closed'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue43769'
versions = ['Python 3.6']

[philipbond]

Hi I came across an issue with the ipaddress module where it doesent raise a ValueError when passed a non IP address.

Example see attached file use tabs for indents and that doesent work with the form.

What happens is it when it takes b'PING' as the call to ipaddress.IPv4Address(address) as the byte value == 4 it doesent raise a ValueError as the bytes for PING are 50 49 4e 47

[philipbond]

To replicate ./cidr-gen.py google.com

You will see the IP variable is a Russian IP but that was a red herring, I initially thought its was a compromised module.

[ericvsmith]

The reproducer is:

>>> ipaddress.IPv4Address(b"PING")
IPv4Address('80.73.78.71')

[ericvsmith]

This is documented behavior. See https://docs.python.org/3/library/ipaddress.html#ipaddress.IPv4Address

"The following constitutes a valid IPv4 address:
...
An integer packed into a bytes object of length 4 (most significant octet first).
"

And the example: 
>>> ipaddress.IPv4Address(b'\xC0\xA8\x00\x01')
IPv4Address('192.168.0.1')

So I'm going to close this as not a bug.