[PATCH 5/9] parser: Handle even more exotically broken headers

Daniel Axtens dja at axtens.net
Thu Feb 22 01:17:12 AEDT 2018

An archive of the Ubuntu kernel team mailing list contains a
fascinating email that causes the following parse error:

email.errors.HeaderParseError: header value appears to contain an embedded header:
  '4Mf^tnii7k\\_EnR5aobBm6Di[DZ9 at AX1wJ"okBdX-UoJ>:SRn]c6DDU"qUIwfs98vF>...

The broken bit seem related to a UTF-8 quoted-printable encoded
section and to be from an internal attempt to break it over multiple
lines: here's a snippet from the error message:
but interesting the header itself does not contain the new lines, so
clearly something quite weird is happening behind the scenes!

This only throws on header.encode(): it actually makes it through
sanitise_header and into find_headers before throwing the assertion.

So, try to encode in sanitize_header as a final step.

Also, fix a hilarious* python bug that this exposes: whitespace-only
headers cause an index error!

Signed-off-by: Daniel Axtens <dja at axtens.net>
 patchwork/parser.py                   |  8 +++++
 patchwork/tests/fuzztests/x-face.mbox | 58 +++++++++++++++++++++++++++++++++++
 patchwork/tests/test_parser.py        |  7 +++--
 3 files changed, 71 insertions(+), 2 deletions(-)
 create mode 100644 patchwork/tests/fuzztests/x-face.mbox

diff --git a/patchwork/parser.py b/patchwork/parser.py
index 2cabb3cbc299..cbf88fe4e464 100644
--- a/patchwork/parser.py
+++ b/patchwork/parser.py
@@ -129,6 +129,14 @@ def sanitise_header(header_contents, header_name=None):
+    try:
+        header.encode()
+    except (HeaderParseError, IndexError):
+        # despite our best efforts, the header is stuffed
+        # HeaderParseError: some very weird multi-line headers
+        # IndexError: bug, thrown by make_header(decode_header(' ')).encode()
+        return None
     return header
diff --git a/patchwork/tests/fuzztests/x-face.mbox b/patchwork/tests/fuzztests/x-face.mbox
new file mode 100644
index 000000000000..98019cff8250
--- /dev/null
+++ b/patchwork/tests/fuzztests/x-face.mbox
@@ -0,0 +1,58 @@
+From laurent.pinchart at skynet.be Thu Nov 13 15:54:10 2008
+Received: from mailrelay005.isp.belgacom.be ([])
+	by chlorine.canonical.com with esmtp (Exim 4.60)
+	(envelope-from <laurent.pinchart at skynet.be>) id 1L0eWI-0007oB-7K
+	for kernel-team at lists.ubuntu.com; Thu, 13 Nov 2008 15:54:10 +0000
+X-IronPort-Anti-Spam-Filtered: true
+X-IronPort-Anti-Spam-Result: ApsEAP/aG0nCTsYx/2dsb2JhbACBds9Hg1c
+Received: from 49.198-78-194.adsl-static.isp.belgacom.be (HELO
+	laptop-laurent.belgium.cse-semaphore.com) ([])
+	by relay.skynet.be with ESMTP; 13 Nov 2008 16:54:09 +0100
+From: Laurent Pinchart <laurent.pinchart at skynet.be>
+To: kernel-team at lists.ubuntu.com
+Subject: uvcvideo (webcam) support for COMPAL JHL90 based laptops
+Date: Thu, 13 Nov 2008 16:54:22 +0100
+User-Agent: KMail/1.9.9
+X-Face: 4Mf^tnii7k\_EnR5aobBm6Di[DZ9 at AX1wJ"okBdX-UoJ>:SRn]c6DDU"qUIwfs98vF>=?utf-8?q?Tnf=0A=09SacR=7B?=(0Du"N%_.#X]"TXx)A'gKB1i7SK$CTLuy{h})c=g:'w3
+MIME-Version: 1.0
+Content-Type: text/plain;
+  charset="us-ascii"
+Content-Transfer-Encoding: 7bit
+Content-Disposition: inline
+Message-Id: <200811131654.22389.laurent.pinchart at skynet.be>
+X-Mailman-Approved-At: Fri, 14 Nov 2008 14:54:06 +0000
+Cc: amit at ubuntu.com
+X-BeenThere: kernel-team at lists.ubuntu.com
+X-Mailman-Version: 2.1.8
+Precedence: list
+List-Id: Kernel team discussions <kernel-team.lists.ubuntu.com>
+List-Unsubscribe: <https://lists.ubuntu.com/mailman/listinfo/kernel-team>,
+	<mailto:kernel-team-request at lists.ubuntu.com?subject=unsubscribe>
+List-Archive: <https://lists.ubuntu.com/archives/kernel-team>
+List-Post: <mailto:kernel-team at lists.ubuntu.com>
+List-Help: <mailto:kernel-team-request at lists.ubuntu.com?subject=help>
+List-Subscribe: <https://lists.ubuntu.com/mailman/listinfo/kernel-team>,
+	<mailto:kernel-team-request at lists.ubuntu.com?subject=subscribe>
+X-List-Received-Date: Thu, 13 Nov 2008 15:54:10 -0000
+Hi Amit,
+I've noticed by sheer luck that the Ubuntu 8.10 linux-image-2.6.27-7 packages 
+include a patch to the uvcvideo driver to support webcam modules integrated 
+into Compal JHL90 laptops.
+Is there a reason why the patch hasn't been pushed upstream ? Being the 
+uvcvideo author and maintainer, I'd appreciate if you could forward patches 
+related to the driver in the future.
+On a pure technical note, the patch might not be required with the current 
+uvcvideo driver version. There is no way to confirm this without testing the 
+driver with that particular webcam model, so I'd appreciate if you could 
+contact the patch author and check with him if his camera works with the 
+latest uvcvideo driver (available from http://linux-uvc.berlios.de/).
+Best regards,
+Laurent Pinchart
diff --git a/patchwork/tests/test_parser.py b/patchwork/tests/test_parser.py
index 20d70af12120..68bcb937b273 100644
--- a/patchwork/tests/test_parser.py
+++ b/patchwork/tests/test_parser.py
@@ -896,8 +896,8 @@ class SubjectTest(TestCase):
         self.assertEqual(parse_version('Hello, world (V6)', []), 6)
-class FuzzTest(TransactionTestCase):
-    """Test fuzzed patches."""
+class WeirdMailTest(TransactionTestCase):
+    """Test fuzzed or otherwise weird patches."""
     def setUp(self):
@@ -940,3 +940,6 @@ class FuzzTest(TransactionTestCase):
+    def test_x_face(self):
+        self._test_patch('x-face.mbox')

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