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From 90d56127ae15b1e452755e62c77dc475dedf7161 Mon Sep 17 00:00:00 2001
From: jpic <jpic@users.noreply.github.com>
Date: Wed, 17 Jul 2019 23:54:25 +0200
Subject: [PATCH] bpo-34155: Dont parse domains containing @ (GH-13079)
Before:
>>> email.message_from_string('From: a@malicious.org@important.com', policy=email.policy.default)['from'].addresses
(Address(display_name='', username='a', domain='malicious.org'),)
>>> parseaddr('a@malicious.org@important.com')
('', 'a@malicious.org')
After:
>>> email.message_from_string('From: a@malicious.org@important.com', policy=email.policy.default)['from'].addresses
(Address(display_name='', username='', domain=''),)
>>> parseaddr('a@malicious.org@important.com')
('', 'a@')
https://bugs.python.org/issue34155
Upstream-Status: Backport [https://github.com/python/cpython/commit/8cb65d1381b027f0b09ee36bfed7f35bb4dec9a9]
CVE: CVE-2019-16056
Signed-off-by: Chen Qi <Qi.Chen@windriver.com>
---
Lib/email/_header_value_parser.py | 2 ++
Lib/email/_parseaddr.py | 11 ++++++++++-
Lib/test/test_email/test__header_value_parser.py | 10 ++++++++++
Lib/test/test_email/test_email.py | 14 ++++++++++++++
.../2019-05-04-13-33-37.bpo-34155.MJll68.rst | 1 +
5 files changed, 37 insertions(+), 1 deletion(-)
create mode 100644 Misc/NEWS.d/next/Security/2019-05-04-13-33-37.bpo-34155.MJll68.rst
diff --git a/Lib/email/_header_value_parser.py b/Lib/email/_header_value_parser.py
index fc00b4a098..bbc026ec71 100644
--- a/Lib/email/_header_value_parser.py
+++ b/Lib/email/_header_value_parser.py
@@ -1582,6 +1582,8 @@ def get_domain(value):
token, value = get_dot_atom(value)
except errors.HeaderParseError:
token, value = get_atom(value)
+ if value and value[0] == '@':
+ raise errors.HeaderParseError('Invalid Domain')
if leader is not None:
token[:0] = [leader]
domain.append(token)
diff --git a/Lib/email/_parseaddr.py b/Lib/email/_parseaddr.py
index cdfa3729ad..41ff6f8c00 100644
--- a/Lib/email/_parseaddr.py
+++ b/Lib/email/_parseaddr.py
@@ -379,7 +379,12 @@ class AddrlistClass:
aslist.append('@')
self.pos += 1
self.gotonext()
- return EMPTYSTRING.join(aslist) + self.getdomain()
+ domain = self.getdomain()
+ if not domain:
+ # Invalid domain, return an empty address instead of returning a
+ # local part to denote failed parsing.
+ return EMPTYSTRING
+ return EMPTYSTRING.join(aslist) + domain
def getdomain(self):
"""Get the complete domain name from an address."""
@@ -394,6 +399,10 @@ class AddrlistClass:
elif self.field[self.pos] == '.':
self.pos += 1
sdlist.append('.')
+ elif self.field[self.pos] == '@':
+ # bpo-34155: Don't parse domains with two `@` like
+ # `a@malicious.org@important.com`.
+ return EMPTYSTRING
elif self.field[self.pos] in self.atomends:
break
else:
diff --git a/Lib/test/test_email/test__header_value_parser.py b/Lib/test/test_email/test__header_value_parser.py
index 693487bc96..7dc4de1b7b 100644
--- a/Lib/test/test_email/test__header_value_parser.py
+++ b/Lib/test/test_email/test__header_value_parser.py
@@ -1438,6 +1438,16 @@ class TestParser(TestParserMixin, TestEmailBase):
self.assertEqual(addr_spec.domain, 'example.com')
self.assertEqual(addr_spec.addr_spec, 'star.a.star@example.com')
+ def test_get_addr_spec_multiple_domains(self):
+ with self.assertRaises(errors.HeaderParseError):
+ parser.get_addr_spec('star@a.star@example.com')
+
+ with self.assertRaises(errors.HeaderParseError):
+ parser.get_addr_spec('star@a@example.com')
+
+ with self.assertRaises(errors.HeaderParseError):
+ parser.get_addr_spec('star@172.17.0.1@example.com')
+
# get_obs_route
def test_get_obs_route_simple(self):
diff --git a/Lib/test/test_email/test_email.py b/Lib/test/test_email/test_email.py
index c29cc56203..aa775881c5 100644
--- a/Lib/test/test_email/test_email.py
+++ b/Lib/test/test_email/test_email.py
@@ -3041,6 +3041,20 @@ class TestMiscellaneous(TestEmailBase):
self.assertEqual(utils.parseaddr('<>'), ('', ''))
self.assertEqual(utils.formataddr(utils.parseaddr('<>')), '')
+ def test_parseaddr_multiple_domains(self):
+ self.assertEqual(
+ utils.parseaddr('a@b@c'),
+ ('', '')
+ )
+ self.assertEqual(
+ utils.parseaddr('a@b.c@c'),
+ ('', '')
+ )
+ self.assertEqual(
+ utils.parseaddr('a@172.17.0.1@c'),
+ ('', '')
+ )
+
def test_noquote_dump(self):
self.assertEqual(
utils.formataddr(('A Silly Person', 'person@dom.ain')),
diff --git a/Misc/NEWS.d/next/Security/2019-05-04-13-33-37.bpo-34155.MJll68.rst b/Misc/NEWS.d/next/Security/2019-05-04-13-33-37.bpo-34155.MJll68.rst
new file mode 100644
index 0000000000..50292e29ed
--- /dev/null
+++ b/Misc/NEWS.d/next/Security/2019-05-04-13-33-37.bpo-34155.MJll68.rst
@@ -0,0 +1 @@
+Fix parsing of invalid email addresses with more than one ``@`` (e.g. a@b@c.com.) to not return the part before 2nd ``@`` as valid email address. Patch by maxking & jpic.
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