bpo-39073: validate Address parts to disallow CRLF (#19007)
Disallow CR or LF in email.headerregistry.Address arguments to guard against header injection attacks.
diff --git a/Lib/email/headerregistry.py b/Lib/email/headerregistry.py
index cc1d191..5d84fc0 100644
--- a/Lib/email/headerregistry.py
+++ b/Lib/email/headerregistry.py
@@ -31,6 +31,11 @@
without any Content Transfer Encoding.
"""
+
+ inputs = ''.join(filter(None, (display_name, username, domain, addr_spec)))
+ if '\r' in inputs or '\n' in inputs:
+ raise ValueError("invalid arguments; address parts cannot contain CR or LF")
+
# This clause with its potential 'raise' may only happen when an
# application program creates an Address object using an addr_spec
# keyword. The email library code itself must always supply username
diff --git a/Lib/test/test_email/test_headerregistry.py b/Lib/test/test_email/test_headerregistry.py
index 38f7ddb..82e1213 100644
--- a/Lib/test/test_email/test_headerregistry.py
+++ b/Lib/test/test_email/test_headerregistry.py
@@ -1437,6 +1437,25 @@
# with self.assertRaises(ValueError):
# Address('foo', 'wők', 'example.com')
+ def test_crlf_in_constructor_args_raises(self):
+ cases = (
+ dict(display_name='foo\r'),
+ dict(display_name='foo\n'),
+ dict(display_name='foo\r\n'),
+ dict(domain='example.com\r'),
+ dict(domain='example.com\n'),
+ dict(domain='example.com\r\n'),
+ dict(username='wok\r'),
+ dict(username='wok\n'),
+ dict(username='wok\r\n'),
+ dict(addr_spec='wok@example.com\r'),
+ dict(addr_spec='wok@example.com\n'),
+ dict(addr_spec='wok@example.com\r\n')
+ )
+ for kwargs in cases:
+ with self.subTest(kwargs=kwargs), self.assertRaisesRegex(ValueError, "invalid arguments"):
+ Address(**kwargs)
+
def test_non_ascii_username_in_addr_spec_raises(self):
with self.assertRaises(ValueError):
Address('foo', addr_spec='wők@example.com')
diff --git a/Misc/NEWS.d/next/Security/2020-03-15-01-28-36.bpo-39073.6Szd3i.rst b/Misc/NEWS.d/next/Security/2020-03-15-01-28-36.bpo-39073.6Szd3i.rst
new file mode 100644
index 0000000..6c9447b
--- /dev/null
+++ b/Misc/NEWS.d/next/Security/2020-03-15-01-28-36.bpo-39073.6Szd3i.rst
@@ -0,0 +1 @@
+Disallow CR or LF in email.headerregistry.Address arguments to guard against header injection attacks.