diff options
| -rw-r--r-- | alot/db/utils.py | 101 | ||||
| -rw-r--r-- | tests/db/utils_test.py | 1 |
2 files changed, 62 insertions, 40 deletions
diff --git a/alot/db/utils.py b/alot/db/utils.py index 8f71f20a..198966ba 100644 --- a/alot/db/utils.py +++ b/alot/db/utils.py @@ -29,6 +29,9 @@ charset.add_charset('utf-8', charset.QP, charset.QP, 'utf-8') X_SIGNATURE_VALID_HEADER = 'X-Alot-OpenPGP-Signature-Valid' X_SIGNATURE_MESSAGE_HEADER = 'X-Alot-OpenPGP-Signature-Message' +_APP_PGP_SIG = 'application/pgp-signature' +_APP_PGP_ENC = 'application/pgp-encrypted' + def add_signature_headers(mail, sigs, error_msg): '''Add pseudo headers to the mail indicating whether the signature @@ -90,6 +93,51 @@ def get_params(mail, failobj=None, header='content-type', unquote=True): return {k.lower(): v for k, v in mail.get_params(failobj, header, unquote)} +def _handle_signatures(original, message, params): + """Shared code for handling message signatures. + + RFC 3156 is quite strict: + * exactly two messages + * the second is of type 'application/pgp-signature' + * the second contains the detached signature + + :param original: The original top-level mail. This is required to attache + special headers to + :type original: :class:`email.message.Message` + :param message: The multipart/signed payload to verify + :type message: :class:`email.message.Message` + :param params: the message parameters as returned by :func:`get_params` + :type params: dict[str, str] + """ + malformed = False + if len(message.get_payload()) != 2: + malformed = u'expected exactly two messages, got {0}'.format( + len(message.get_payload())) + else: + ct = message.get_payload(1).get_content_type() + if ct != _APP_PGP_SIG: + malformed = u'expected Content-Type: {0}, got: {1}'.format( + _APP_PGP_SIG, ct) + + # TODO: RFC 3156 says the alg has to be lower case, but I've seen a message + # with 'PGP-'. maybe we should be more permissive here, or maybe not, this + # is crypto stuff... + if not params.get('micalg', 'nothing').startswith('pgp-'): + malformed = u'expected micalg=pgp-..., got: {0}'.format( + params.get('micalg', 'nothing')) + + sigs = [] + if not malformed: + try: + sigs = crypto.verify_detached( + helper.email_as_string(message.get_payload(0)), + message.get_payload(1).get_payload()) + except GPGProblem as e: + malformed = unicode(e) + + add_signature_headers(original, sigs, malformed) + + def message_from_file(handle): '''Reads a mail from the given file-like object and returns an email object, very much like email.message_from_file. In addition to @@ -108,50 +156,25 @@ def message_from_file(handle): del m[X_SIGNATURE_MESSAGE_HEADER] p = get_params(m) - app_pgp_sig = 'application/pgp-signature' - app_pgp_enc = 'application/pgp-encrypted' # handle OpenPGP signed data if (m.is_multipart() and m.get_content_subtype() == 'signed' and - p.get('protocol') == app_pgp_sig): - # RFC 3156 is quite strict: - # * exactly two messages - # * the second is of type 'application/pgp-signature' - # * the second contains the detached signature - - malformed = False - if len(m.get_payload()) != 2: - malformed = u'expected exactly two messages, got {0}'.format( - len(m.get_payload())) - else: - ct = m.get_payload(1).get_content_type() - if ct != app_pgp_sig: - malformed = u'expected Content-Type: {0}, got: {1}'.format( - app_pgp_sig, ct) - - # TODO: RFC 3156 says the alg has to be lower case, but I've - # seen a message with 'PGP-'. maybe we should be more - # permissive here, or maybe not, this is crypto stuff... - if not p.get('micalg', 'nothing').startswith('pgp-'): - malformed = u'expected micalg=pgp-..., got: {0}'.format( - p.get('micalg', 'nothing')) - - sigs = [] - if not malformed: - try: - sigs = crypto.verify_detached( - helper.email_as_string(m.get_payload(0)), - m.get_payload(1).get_payload()) - except GPGProblem as e: - malformed = unicode(e) - - add_signature_headers(m, sigs, malformed) - + p.get('protocol') == _APP_PGP_SIG): + _handle_signatures(m, m, p) + elif (m.is_multipart() and m.get_content_subtype() == 'mixed' and + m.get_payload(0).get_content_subtype() == 'signed'): + p = get_params(m.get_payload(0)) + if p.get('protocol') == _APP_PGP_SIG: + _handle_signatures(m, m.get_payload(0), p) + + # XXX: It is presumably possible to put an encrypted message in a + # multipart/mixed, but I have no such examples and haven't looked through + # RFC's thuroughly # handle OpenPGP encrypted data elif (m.is_multipart() and m.get_content_subtype() == 'encrypted' and - p.get('protocol') == app_pgp_enc and + p.get('protocol') == _APP_PGP_ENC and 'Version: 1' in m.get_payload(0).get_payload()): # RFC 3156 is quite strict: # * exactly two messages @@ -162,9 +185,9 @@ def message_from_file(handle): malformed = False ct = m.get_payload(0).get_content_type() - if ct != app_pgp_enc: + if ct != _APP_PGP_ENC: malformed = u'expected Content-Type: {0}, got: {1}'.format( - app_pgp_enc, ct) + _APP_PGP_ENC, ct) want = 'application/octet-stream' ct = m.get_payload(1).get_content_type() diff --git a/tests/db/utils_test.py b/tests/db/utils_test.py index ea0b6f20..d2c92577 100644 --- a/tests/db/utils_test.py +++ b/tests/db/utils_test.py @@ -593,7 +593,6 @@ class TestMessageFromFile(TestCaseClassCleanup): self.assertIn('Malformed OpenPGP message:', m.get_payload(2).get_payload()) - @unittest.expectedFailure def test_signed_in_multipart_mixed(self): """It is valid to encapsulate a multipart/signed payload inside a multipart/mixed payload, verify that works. |