bpo-38708: email: Fix a potential IndexError when parsing Message-ID (GH-17504)
Fix a potential IndexError when passing an empty value to the message-id
parser. Instead, HeaderParseError should be raised.
(cherry picked from commit 3ae4ea1931361dd2743e464790e739d9285501bf)
Co-authored-by: Abhilash Raj <maxking@users.noreply.github.com>
diff --git a/Lib/email/_header_value_parser.py b/Lib/email/_header_value_parser.py
index cb01322..9c55ef7 100644
--- a/Lib/email/_header_value_parser.py
+++ b/Lib/email/_header_value_parser.py
@@ -2047,7 +2047,7 @@
no-fold-literal = "[" *dtext "]"
"""
msg_id = MsgID()
- if value[0] in CFWS_LEADER:
+ if value and value[0] in CFWS_LEADER:
token, value = get_cfws(value)
msg_id.append(token)
if not value or value[0] != '<':
diff --git a/Lib/test/test_email/test__header_value_parser.py b/Lib/test/test_email/test__header_value_parser.py
index 7c9f987..4b5b442 100644
--- a/Lib/test/test_email/test__header_value_parser.py
+++ b/Lib/test/test_email/test__header_value_parser.py
@@ -2583,6 +2583,11 @@
# get_msg_id
+ def test_get_msg_id_empty(self):
+ # bpo-38708: Test that HeaderParseError is raised and not IndexError.
+ with self.assertRaises(errors.HeaderParseError):
+ parser.get_msg_id('')
+
def test_get_msg_id_valid(self):
msg_id = self._test_get_x(
parser.get_msg_id,
@@ -2694,6 +2699,7 @@
self.assertEqual(msg_id.token_type, 'msg-id')
+
@parameterize
class Test_parse_mime_parameters(TestParserMixin, TestEmailBase):
diff --git a/Misc/NEWS.d/next/Library/2019-12-07-22-25-39.bpo-38708.rZTUfk.rst b/Misc/NEWS.d/next/Library/2019-12-07-22-25-39.bpo-38708.rZTUfk.rst
new file mode 100644
index 0000000..23a0a46
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2019-12-07-22-25-39.bpo-38708.rZTUfk.rst
@@ -0,0 +1 @@
+Fix a potential IndexError in email parser when parsing an empty msg-id.
