bpo-39073: validate Address parts to disallow CRLF (GH-19007) (#19224)
Disallow CR or LF in email.headerregistry.Address arguments to guard against header injection attacks.
(cherry picked from commit 614f17211c5fc0e5b828be1d3320661d1038fe8f)
The AbstractBasicAuthHandler class of the urllib.request module uses
an inefficient regular expression which can be exploited by an
attacker to cause a denial of service. Fix the regex to prevent the
catastrophic backtracking. Vulnerability reported by Ben Caller
and Matt Schwager.
AbstractBasicAuthHandler of urllib.request now parses all
WWW-Authenticate HTTP headers and accepts multiple challenges per
header: use the realm of the first Basic challenge.
closes bpo-39510: Fix use-after-free in BufferedReader.readinto() (GH-18350)
When called on a closed object, readinto() segfaults on account
of a write to a freed buffer:
==220553== Process terminating with default action of signal 11 (SIGSEGV): dumping core
==220553== Access not within mapped region at address 0x2A
==220553== at 0x48408A0: memmove (vg_replace_strmem.c:1272)
==220553== by 0x58DB0C: _buffered_readinto_generic (bufferedio.c:972)
==220553== by 0x58DCBA: _io__Buffered_readinto_impl (bufferedio.c:1053)
==220553== by 0x58DCBA: _io__Buffered_readinto (bufferedio.c.h:253)
bpo-38804: Fix REDoS in http.cookiejar (GH-17157) (#17343)
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.
class Handler(BaseHTTPRequestHandler):
def do_GET(self):
self.log_request(204)
self.send_response_only(204) GH- Don't bother sending Server and Date
n_spaces = (
int(self.path[1:]) GH- Can GET e.g. /100 to test shorter sequences
if len(self.path) > 1 else
65506 GH- Max header line length 65536
)
value = make_set_cookie_value(n_spaces)
for i in range(99): GH- 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):
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.
(cherry picked from commit 1b779bfb8593739b11cbb988ef82a883ec9d077e)
[3.6] closes bpo-38174: Update vendored expat library to 2.2.8. (GH-16410)
Fixes CVE-2019-15903. See full changelog at https://github.com/libexpat/libexpat/blob/R_2_2_8/expat/Changes..
(cherry picked from commit 52b940803860e37bcc3f6096b2d24e7c20a0e807)
bpo-37461: Fix infinite loop in parsing of specially crafted email headers (GH-14794) (GH-14817)
Some crafted email header would cause the get_parameter method to run in an
infinite loop causing a DoS attack surface when parsing those headers. This
patch fixes that by making sure the DQUOTE character is handled to prevent
going into an infinite loop.
(cherry picked from commit a4a994bd3e619cbaff97610a1cee8ffa87c672f5)
Fix infinite loop in email folding logic (GH-12732) (GH-14799)
As far as I can tell, this infinite loop would be triggered if:
1. The value being folded contains a single word (no spaces) longer than
max_line_length
2. The max_line_length is shorter than the encoding's name + 9
characters.
Under some conditions the earlier fix for bpo-18075, "Infinite recursion
tests triggering a segfault on Mac OS X", now causes failures on macOS
when attempting to change stack limit with resource.setrlimit
resource.RLIMIT_STACK, like regrtest does when running the test suite.
The reverted change had specified a non-default stack size when linking
the python executable on macOS. As of macOS 10.14.4, the previous
code causes a hard failure when running tests, although similar
failures had been seen under some conditions under some earlier
systems. Reverting the change to the interpreter stack size at link
time helped for release builds but caused some tests to fail when
built --with-pydebug. Try the opposite approach: continue to build
the interpreter with an increased stack size on macOS and remove
the failing setrlimit call in regrtest initialization. This will
definitely avoid the resource.RLIMIT_STACK error and should have
no, or fewer, side effects.
(cherry picked from commit 5bbbc733e6cc0804f19b071944af8d4719e26ae6)
CVE-2019-9948: Avoid file reading by disallowing local-file:// and
local_file:// URL schemes in URLopener().open() and
URLopener().retrieve() of urllib.request.
Gregory P. Smith [Wed, 29 May 2019 02:08:28 +0000 (19:08 -0700)]
[3.6] bpo-35925: Skip SSL tests that fail due to weak external certs or old TLS (GH-13124) (GH-13252)
* [3.6] bpo-35925: Skip SSL tests that fail due to weak external certs. (GH-13124)
Modern Linux distros such as Debian Buster have default OpenSSL system
configurations that reject connections to servers with weak certificates
by default. This causes our test suite run with external networking
resources enabled to skip these tests when they encounter such a failure.
Miro Hrončok [Wed, 8 May 2019 16:33:24 +0000 (18:33 +0200)]
bpo-30458: Disallow control chars in http URLs. (GH-12755) (GH-13155)
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.
Disable https related urllib tests on a build without ssl (GH-13032)
These tests require an SSL enabled build. Skip these tests when python is built without SSL to fix test failures.
Use http.client.InvalidURL instead of ValueError as the new error case's exception. (GH-13044)
Under some conditions the earlier fix for bpo-18075, "Infinite recursion
tests triggering a segfault on Mac OS X", now causes failures on macOS
when attempting to change stack limit with resource.setrlimit
resource.RLIMIT_STACK, like regrtest does when running the test suite.
The reverted change had specified a non-default stack size when linking
the python executable on macOS. As of macOS 10.14.4, the previous
code causes a hard failure when running tests, although similar
failures had been seen under some conditions under some earlier
systems. For now, revert the original change and resume using
the default stack size when linking the interpreter.
(cherry picked from commit 883dfc668f9730b00928730035b5dbd24b9da2a0)
bpo-35121: prefix dot in domain for proper subdomain validation (GH-10258) (GH-12260)
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.
(cherry picked from commit ca7fe5063593958e5efdf90f068582837f07bd14)
bpo-35486: Note Py3.6 import system API requirement change (GH-11540) (GH-11588)
While the introduction of ModuleNotFoundError was fully backwards
compatible on the import API consumer side, folks providing alternative
implementations of `__import__` need to make an update to be
forward compatible with clients that start relying on the new subclass.
bpo-35601: Alleviate race condition when waiting for SIGALRM in test_asyncio (GH-11337) (GH-11348)
There is a race condition regarding signal delivery in test_signal_handling_args for
test_asyncio.test_events.KqueueEventLoopTests. The signal can be received at any moment outside the time window provided in the test. The fix is to wait for the signal to be received instead with a bigger timeout.
(cherry picked from commit 5471420faa84519530f29b08f2b042b2288e3e96)
Co-authored-by: Pablo Galindo <Pablogsal@gmail.com>
bpo-35746: Fix segfault in ssl's cert parser (GH-11569) (GH-11573)
Fix a NULL pointer deref in ssl module. The cert parser did not handle CRL
distribution points with empty DP or URI correctly. A malicious or buggy
certificate can result into segfault.
Due to regressions found with using Tk 8.6.9.1, the python.org macOS
installers for 3.6.8 and 3.7.2 are shipping with Tcl/Tk 8.6.8 as used
in previous releases.
bpo-35257: fix broken BLDSHARED - needs LDFLAGS too (GH-11297) (GH-11299)
`BLDSHARED` needs to have both `LDFLAGS` and `LDFLAGS_NODIST`, not just `LDFLAGS_NODIST`; `PY_CORE_LDFLAGS` provides both. For example, as it stands now with just `LDFLAGS_NODIST`, macOS universal builds are broken as the necessary `-arch` flags are no longer passed to the standard library extension module link step from `setup.py` resulting in extension modules being single architecture only.
When compiling 3rd party C extensions, the linker flags used by the
compiler for the interpreter and the stdlib modules, will get
leaked into distutils. In order to avoid that, the PY_CORE_LDFLAGS
and PY_LDFLAGS_NODIST are introduced to keep those flags separated.
Victor Stinner [Thu, 20 Dec 2018 19:46:07 +0000 (20:46 +0100)]
bpo-35499: make profile-opt don't override CFLAGS_NODIST (GH-11164) (GH-11267)
"make profile-opt" no longer replaces CFLAGS_NODIST with CFLAGS. It
now adds profile-guided optimization (PGO) flags to CFLAGS_NODIST,
existing CFLAGS_NODIST flags are kept.
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