bpo-43124: Fix smtplib multiple CRLF injection by miguendes · Pull Request #25987 · python/cpython · GitHub
Skip to content

bpo-43124: Fix smtplib multiple CRLF injection #25987

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
ambv merged 3 commits into from
Aug 29, 2021
Merged

bpo-43124: Fix smtplib multiple CRLF injection #25987

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
3 commits
Select commit Hold shift + click to select a range
ec13383
Fix smtplib multiple CRLF injection
miguendes May 8, 2021
4e0ee17
Respond to R. David Murray review suggestions
ambv Aug 29, 2021
61f2871
Improve Blurb wording
ambv Aug 29, 2021
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
11 changes: 8 additions & 3 deletions Lib/smtplib.py
View file
Open in desktop
55 changes: 55 additions & 0 deletions Lib/test/test_smtplib.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -336,6 +336,16 @@ def testEXPNNotImplemented(self):
self.assertEqual(smtp.getreply(), expected)
smtp.quit()

def test_issue43124_putcmd_escapes_newline(self):
# see: https://bugs.python.org/issue43124
smtp = smtplib.SMTP(HOST, self.port, local_hostname='localhost',
timeout=support.LOOPBACK_TIMEOUT)
self.addCleanup(smtp.close)
with self.assertRaises(ValueError) as exc:
smtp.putcmd('helo\nX-INJECTED')
self.assertIn("prohibited newline characters", str(exc.exception))
smtp.quit()

def testVRFY(self):
smtp = smtplib.SMTP(HOST, self.port, local_hostname='localhost',
timeout=support.LOOPBACK_TIMEOUT)
Expand Down Expand Up @@ -417,6 +427,51 @@ def testSendNeedingDotQuote(self):
mexpect = '%s%s\n%s' % (MSG_BEGIN, m, MSG_END)
self.assertEqual(self.output.getvalue(), mexpect)

def test_issue43124_escape_localhostname(self):
# see: https://bugs.python.org/issue43124
# connect and send mail
m = 'wazzuuup\nlinetwo'
smtp = smtplib.SMTP(HOST, self.port, local_hostname='hi\nX-INJECTED',
timeout=support.LOOPBACK_TIMEOUT)
self.addCleanup(smtp.close)
with self.assertRaises(ValueError) as exc:
smtp.sendmail("hi@me.com", "you@me.com", m)
self.assertIn(
"prohibited newline characters: ehlo hi\\nX-INJECTED",
str(exc.exception),
)
# XXX (see comment in testSend)
time.sleep(0.01)
smtp.quit()

debugout = smtpd.DEBUGSTREAM.getvalue()
self.assertNotIn("X-INJECTED", debugout)

def test_issue43124_escape_options(self):
# see: https://bugs.python.org/issue43124
# connect and send mail
m = 'wazzuuup\nlinetwo'
smtp = smtplib.SMTP(
HOST, self.port, local_hostname='localhost',
timeout=support.LOOPBACK_TIMEOUT)

self.addCleanup(smtp.close)
smtp.sendmail("hi@me.com", "you@me.com", m)
with self.assertRaises(ValueError) as exc:
smtp.mail("hi@me.com", ["X-OPTION\nX-INJECTED-1", "X-OPTION2\nX-INJECTED-2"])
msg = str(exc.exception)
self.assertIn("prohibited newline characters", msg)
self.assertIn("X-OPTION\\nX-INJECTED-1 X-OPTION2\\nX-INJECTED-2", msg)
# XXX (see comment in testSend)
time.sleep(0.01)
smtp.quit()

debugout = smtpd.DEBUGSTREAM.getvalue()
self.assertNotIn("X-OPTION", debugout)
self.assertNotIn("X-OPTION2", debugout)
self.assertNotIn("X-INJECTED-1", debugout)
self.assertNotIn("X-INJECTED-2", debugout)

def testSendNullSender(self):
m = 'A test message'
smtp = smtplib.SMTP(HOST, self.port, local_hostname='localhost',
Expand Down
2 changes: 2 additions & 0 deletions Misc/NEWS.d/next/Security/2021-05-08-11-50-46.bpo-43124.2CTM6M.rst
View file
Open in desktop