File CVE-2019-16056-email-parse-addr.patch of Package python3-doc.18721

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File CVE-2019-16056-email-parse-addr.patch of Package python3-doc.18721

From 3263dacf50e94352fcb3f97cfbc80cfee5723a56 Mon Sep 17 00:00:00 2001
From: jpic <jpic@yourlabs.org>
Date: Wed, 3 Jul 2019 07:27:12 +0200
Subject: [PATCH] bpo-34155: Fail parse of multiple email domains

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')
    ('', '')

Thanks @maxking for kind patch review and patch contribution.
---
 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

--- a/Lib/email/_header_value_parser.py
+++ b/Lib/email/_header_value_parser.py
@@ -1963,6 +1963,8 @@ 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)
--- 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:
--- a/Lib/test/test_email/test__header_value_parser.py
+++ b/Lib/test/test_email/test__header_value_parser.py
@@ -1418,6 +1418,16 @@ class TestParser(TestParserMixin, TestEm
         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):
--- a/Lib/test/test_email/test_email.py
+++ b/Lib/test/test_email/test_email.py
@@ -2984,6 +2984,20 @@ 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')),
--- /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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File CVE-2019-16056-email-parse-addr.patch of Package python3-doc.18721

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