From 439b9cfaf43080e91c4ad69f312f21fa098befc7 Mon Sep 17 00:00:00 2001
From: Ben Kallus <49924171+kenballus@users.noreply.github.com>
Date: Sun, 13 Nov 2022 18:25:55 +0000
Subject: [PATCH] gh-99418: Make urllib.parse.urlparse enforce that a scheme
must begin with an alphabetical ASCII character. (#99421)
Prevent urllib.parse.urlparse from accepting schemes that don't begin with an alphabetical ASCII character.
RFC 3986 defines a scheme like this: `scheme = ALPHA *( ALPHA / DIGIT / "+" / "-" / "." )`
RFC 2234 defines an ALPHA like this: `ALPHA = %x41-5A / %x61-7A`
The WHATWG URL spec defines a scheme like this:
`"A URL-scheme string must be one ASCII alpha, followed by zero or more of ASCII alphanumeric, U+002B (+), U+002D (-), and U+002E (.)."`
---
Lib/test/test_urlparse.py | 18 ++++++++++++++++++
Lib/urllib/parse.py | 2 +-
...22-11-12-15-45-51.gh-issue-99418.FxfAXS.rst | 2 ++
3 files changed, 21 insertions(+), 1 deletion(-)
create mode 100644 Misc/NEWS.d/next/Library/2022-11-12-15-45-51.gh-issue-99418.FxfAXS.rst
diff --git a/Lib/test/test_urlparse.py b/Lib/test/test_urlparse.py
index 59a601d9e85..80fb9e5cd2a 100644
--- a/Lib/test/test_urlparse.py
+++ b/Lib/test/test_urlparse.py
@@ -668,6 +668,24 @@ def test_attributes_bad_port(self):
with self.assertRaises(ValueError):
p.port
+ def test_attributes_bad_scheme(self):
+ """Check handling of invalid schemes."""
+ for bytes in (False, True):
+ for parse in (urllib.parse.urlsplit, urllib.parse.urlparse):
+ for scheme in (".", "+", "-", "0", "http&", "६http"):
+ with self.subTest(bytes=bytes, parse=parse, scheme=scheme):
+ url = scheme + "://www.example.net"
+ if bytes:
+ if url.isascii():
+ url = url.encode("ascii")
+ else:
+ continue
+ p = parse(url)
+ if bytes:
+ self.assertEqual(p.scheme, b"")
+ else:
+ self.assertEqual(p.scheme, "")
+
def test_attributes_without_netloc(self):
# This example is straight from RFC 3261. It looks like it
# should allow the username, hostname, and port to be filled
diff --git a/Lib/urllib/parse.py b/Lib/urllib/parse.py
index 9a3102afd63..4f6867accbc 100644
--- a/Lib/urllib/parse.py
+++ b/Lib/urllib/parse.py
@@ -460,7 +460,7 @@ def urlsplit(url, scheme='', allow_fragments=True):
allow_fragments = bool(allow_fragments)
netloc = query = fragment = ''
i = url.find(':')
- if i > 0:
+ if i > 0 and url[0].isascii() and url[0].isalpha():
for c in url[:i]:
if c not in scheme_chars:
break
diff --git a/Misc/NEWS.d/next/Library/2022-11-12-15-45-51.gh-issue-99418.FxfAXS.rst b/Misc/NEWS.d/next/Library/2022-11-12-15-45-51.gh-issue-99418.FxfAXS.rst
new file mode 100644
index 00000000000..0a06e7c5c6a
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2022-11-12-15-45-51.gh-issue-99418.FxfAXS.rst
@@ -0,0 +1,2 @@
+Fix bug in :func:`urllib.parse.urlparse` that causes URL schemes that begin
+with a digit, a plus sign, or a minus sign to be parsed incorrectly.
--
GitLab