filtermail: more robust check_encrypted()

This commit is contained in:
link2xt
2023-10-15 16:47:30 +00:00
parent df6ec4bd6d
commit 20b7af9d71
2 changed files with 235 additions and 6 deletions

View File

@@ -1,17 +1,33 @@
#!/usr/bin/env python3 #!/usr/bin/env python3
import asyncio import asyncio
import logging import logging
from email.parser import BytesParser
from email import policy
from aiosmtpd.lmtp import LMTP from aiosmtpd.lmtp import LMTP
from aiosmtpd.controller import UnixSocketController from aiosmtpd.controller import UnixSocketController
from smtplib import SMTP as SMTPClient from smtplib import SMTP as SMTPClient
def check_encrypted(envelope): def check_encrypted(content):
"""https://xkcd.com/1181/""" """Check that the message is an OpenPGP-encrypted message."""
return "-----BEGIN PGP MESSAGE-----" in envelope.content.decode( message = BytesParser(policy=policy.default).parsebytes(content)
"utf8", errors="replace" if not message.is_multipart():
) return False
if message.get_content_type() != "multipart/encrypted":
return False
parts_count = 0
for part in message.iter_parts():
if parts_count == 0:
if part.get_content_type() != "application/pgp-encrypted":
return False
elif parts_count == 1:
if part.get_content_type() != "application/octet-stream":
return False
else:
return False
parts_count += 1
return True
class ExampleController(UnixSocketController): class ExampleController(UnixSocketController):
@@ -29,7 +45,7 @@ class ExampleHandler:
valid_recipients = [] valid_recipients = []
mail_encrypted = check_encrypted(envelope) mail_encrypted = check_encrypted(envelope.content)
res = [] res = []
for recipient in envelope.rcpt_tos: for recipient in envelope.rcpt_tos:

View File

@@ -0,0 +1,213 @@
import pytest
from .filtermail import check_encrypted
def test_filtermail():
assert not check_encrypted(b"foo")
assert not check_encrypted(
"\r\n".join(
[
"Subject: =?utf-8?q?Message_from_foobar=40c2=2Etestrun=2Eorg?=",
"Chat-Disposition-Notification-To: foobar@c2.testrun.org",
"Chat-User-Avatar: 0",
"From: <foobar@c2.testrun.org>",
"To: <barbaz@c2.testrun.org>",
"Date: Sun, 15 Oct 2023 16:41:44 +0000",
"Message-ID: <Mr.3gckbNy5bch.uK3Hd2Ws6-w@c2.testrun.org>",
"References: <Mr.3gckbNy5bch.uK3Hd2Ws6-w@c2.testrun.org>",
"Chat-Version: 1.0",
"Autocrypt: addr=foobar@c2.testrun.org; prefer-encrypt=mutual;",
"\tkeydata=xjMEZSrw3hYJKwYBBAHaRw8BAQdAiEKNQFU28c6qsx4vo/JHdt73RXdjMOmByf/XsGiJ7m",
"\tnNFzxmb29iYXJAYzIudGVzdHJ1bi5vcmc+wosEEBYIADMCGQEFAmUq8N4CGwMECwkIBwYVCAkKCwID",
"\tFgIBFiEEGil0OvTIa6RngmCLUYNnEa9leJAACgkQUYNnEa9leJCX3gEAhm0MehE5byBBU1avPczr/I",
"\tHjNLht7Qf6++mAhlJmtDcA/0C8VYJhsUpmiDjuZaMDWNv4FO2BJG6LH7gSm6n7ClMJzjgEZSrw3hIK",
"\tKwYBBAGXVQEFAQEHQAxGG/QW0owCfMp1A+vXEMwgzWcBpNFr58kX2eXuPpM6AwEIB8J4BBgWCAAgBQ",
"\tJlKvDeAhsMFiEEGil0OvTIa6RngmCLUYNnEa9leJAACgkQUYNnEa9leJDg1gEAwLf8KDoAAKyYgjyI",
"\tvYvO9VEgBni1C4Xx1VjcaEmlDK8BALoFuUCK+enw76TtDcAUKhlhUiM6SDRExkS4Nskp/BcK",
"MIME-Version: 1.0",
"Content-Type: text/plain; charset=utf-8; format=flowed; delsp=no",
"",
"Hi!",
"",
"",
]
).encode()
)
assert not check_encrypted(
"\r\n".join(
[
"Subject: =?utf-8?q?Message_from_foobar=40c2=2Etestrun=2Eorg?=",
"Chat-Disposition-Notification-To: foobar@c2.testrun.org",
"Chat-User-Avatar: 0",
"From: <foobar@c2.testrun.org>",
"To: <barbaz@c2.testrun.org>",
"Date: Sun, 15 Oct 2023 16:41:44 +0000",
"Message-ID: <Mr.3gckbNy5bch.uK3Hd2Ws6-w@c2.testrun.org>",
"References: <Mr.3gckbNy5bch.uK3Hd2Ws6-w@c2.testrun.org>",
"Chat-Version: 1.0",
"Autocrypt: addr=foobar@c2.testrun.org; prefer-encrypt=mutual;",
"\tkeydata=xjMEZSrw3hYJKwYBBAHaRw8BAQdAiEKNQFU28c6qsx4vo/JHdt73RXdjMOmByf/XsGiJ7m",
"\tnNFzxmb29iYXJAYzIudGVzdHJ1bi5vcmc+wosEEBYIADMCGQEFAmUq8N4CGwMECwkIBwYVCAkKCwID",
"\tFgIBFiEEGil0OvTIa6RngmCLUYNnEa9leJAACgkQUYNnEa9leJCX3gEAhm0MehE5byBBU1avPczr/I",
"\tHjNLht7Qf6++mAhlJmtDcA/0C8VYJhsUpmiDjuZaMDWNv4FO2BJG6LH7gSm6n7ClMJzjgEZSrw3hIK",
"\tKwYBBAGXVQEFAQEHQAxGG/QW0owCfMp1A+vXEMwgzWcBpNFr58kX2eXuPpM6AwEIB8J4BBgWCAAgBQ",
"\tJlKvDeAhsMFiEEGil0OvTIa6RngmCLUYNnEa9leJAACgkQUYNnEa9leJDg1gEAwLf8KDoAAKyYgjyI",
"\tvYvO9VEgBni1C4Xx1VjcaEmlDK8BALoFuUCK+enw76TtDcAUKhlhUiM6SDRExkS4Nskp/BcK",
"MIME-Version: 1.0",
"Content-Type: text/plain; charset=utf-8; format=flowed; delsp=no",
"",
"Hi!",
"",
"",
]
).encode()
)
# https://xkcd.com/1181/
assert not check_encrypted(
"\r\n".join(
[
"Subject: =?utf-8?q?Message_from_foobar=40c2=2Etestrun=2Eorg?=",
"Chat-Disposition-Notification-To: foobar@c2.testrun.org",
"Chat-User-Avatar: 0",
"From: <foobar@c2.testrun.org>",
"To: <barbaz@c2.testrun.org>",
"Date: Sun, 15 Oct 2023 16:41:44 +0000",
"Message-ID: <Mr.3gckbNy5bch.uK3Hd2Ws6-w@c2.testrun.org>",
"References: <Mr.3gckbNy5bch.uK3Hd2Ws6-w@c2.testrun.org>",
"Chat-Version: 1.0",
"Autocrypt: addr=foobar@c2.testrun.org; prefer-encrypt=mutual;",
"\tkeydata=xjMEZSrw3hYJKwYBBAHaRw8BAQdAiEKNQFU28c6qsx4vo/JHdt73RXdjMOmByf/XsGiJ7m",
"\tnNFzxmb29iYXJAYzIudGVzdHJ1bi5vcmc+wosEEBYIADMCGQEFAmUq8N4CGwMECwkIBwYVCAkKCwID",
"\tFgIBFiEEGil0OvTIa6RngmCLUYNnEa9leJAACgkQUYNnEa9leJCX3gEAhm0MehE5byBBU1avPczr/I",
"\tHjNLht7Qf6++mAhlJmtDcA/0C8VYJhsUpmiDjuZaMDWNv4FO2BJG6LH7gSm6n7ClMJzjgEZSrw3hIK",
"\tKwYBBAGXVQEFAQEHQAxGG/QW0owCfMp1A+vXEMwgzWcBpNFr58kX2eXuPpM6AwEIB8J4BBgWCAAgBQ",
"\tJlKvDeAhsMFiEEGil0OvTIa6RngmCLUYNnEa9leJAACgkQUYNnEa9leJDg1gEAwLf8KDoAAKyYgjyI",
"\tvYvO9VEgBni1C4Xx1VjcaEmlDK8BALoFuUCK+enw76TtDcAUKhlhUiM6SDRExkS4Nskp/BcK",
"MIME-Version: 1.0",
"Content-Type: text/plain; charset=utf-8; format=flowed; delsp=no",
"",
"-----BEGIN PGP MESSAGE-----",
"Hi!",
"-----END PGP MESSAGE-----",
"",
"",
]
).encode()
)
assert check_encrypted(
"\r\n".join(
[
"Subject: ...",
"From: <barbaz@c2.testrun.org>",
"To: <foobar@c2.testrun.org>",
"Date: Sun, 15 Oct 2023 16:43:21 +0000",
"Message-ID: <Mr.UVyJWZmkCKM.hGzNc6glBE_@c2.testrun.org>",
"In-Reply-To: <Mr.MvmCz-GQbi_.6FGRkhDf05c@c2.testrun.org>",
"References: <Mr.3gckbNy5bch.uK3Hd2Ws6-w@c2.testrun.org>",
"\t<Mr.MvmCz-GQbi_.6FGRkhDf05c@c2.testrun.org>",
"Chat-Version: 1.0",
"Autocrypt: addr=barbaz@c2.testrun.org; prefer-encrypt=mutual;",
"\tkeydata=xjMEZSwWjhYJKwYBBAHaRw8BAQdAQBEhqeJh0GueHB6kF/DUQqYCxARNBVokg/AzT+7LqH",
"\trNFzxiYXJiYXpAYzIudGVzdHJ1bi5vcmc+wosEEBYIADMCGQEFAmUsFo4CGwMECwkIBwYVCAkKCwID",
"\tFgIBFiEEFTfUNvVnY3b9F7yHnmme1PfUhX8ACgkQnmme1PfUhX9A4AEAnHWHp49eBCMHK5t66gYPiW",
"\tXQuB1mwUjzGfYWB+0RXUoA/0xcQ3FbUNlGKW7Blp6eMFfViv6Mv2d3kNSXACB6nmcMzjgEZSwWjhIK",
"\tKwYBBAGXVQEFAQEHQBpY5L2M1XHo0uxf8SX1wNLBp/OVvidoWHQF2Jz+kJsUAwEIB8J4BBgWCAAgBQ",
"\tJlLBaOAhsMFiEEFTfUNvVnY3b9F7yHnmme1PfUhX8ACgkQnmme1PfUhX/INgEA37AJaNvruYsJVanP",
"\tIXnYw4CKd55UAwl8Zcy+M2diAbkA/0fHHcGV4r78hpbbL1Os52DPOdqYQRauIeJUeG+G6bQO",
"MIME-Version: 1.0",
'Content-Type: multipart/encrypted; protocol="application/pgp-encrypted";',
'\tboundary="YFrteb74qSXmggbOxZL9dRnhymywAi"',
"",
"",
"--YFrteb74qSXmggbOxZL9dRnhymywAi",
"Content-Description: PGP/MIME version identification",
"Content-Type: application/pgp-encrypted",
"",
"Version: 1",
"",
"",
"--YFrteb74qSXmggbOxZL9dRnhymywAi",
"Content-Description: OpenPGP encrypted message",
'Content-Disposition: inline; filename="encrypted.asc";',
'Content-Type: application/octet-stream; name="encrypted.asc"',
"",
"-----BEGIN PGP MESSAGE-----",
"",
"wU4DhW3gBZ/VvCYSAQdA8bMs2spwbKdGjVsL1ByPkNrqD7frpB73maeL6I6SzDYg",
"O5G53tv339RdKq3WRcCtEEvxjHlUx2XNwXzC04BpmfvBTgNfPUyLDzjXnxIBB0Ae",
"8ymwGvXMCCimHXN0Dg8Ui62KOi03h0UgheoHWovJSCDF4CKre/xtFr3nL7lq/PKI",
"JsjVNz7/RK9FSXF6WwfONtLCyQGEuVAsB/KXfCBEyfKhaMwGHvhujRidGW5uV1no",
"lMGl3ODmo29Lgeu2uSE7EpJRZoe6hU6ddmBkqxax61ZtkaFlGFFpdo2K8balNNdz",
"ZsJ/9mmI9x3oOJ4/l1nhQbUO9ADbs7gJhFdV5Qkp30b5fCI7bU+aoe1ccBbLe/WM",
"YUty1PqcuQT7XjA+XmYuL261tvW8pBetT+i33/E2d8PzzYt2IuK9qeevyS+yxdwA",
"kfwejFWzzsUlJaDxs1x4XOxkMgSj+jo+g12dFOb7fyClsAnq23iDb8AuaT/BScAI",
"+lO+gher69+6LmM7VGHLG5k762J1jTaQCaKt1s8TAWV99Eo4491vL6fyvk3l/Cfg",
"RXSwiWFgj19Pn0Rq7CD9v22UE2vdUMBTcV4aw79mClk1YQ23jbF0y5DCjPdJ62Zo",
"tskBgFt3NoWV80jZ76zIBLrrjLwCCll8JjJtFwSkt2GX5RFBsVa4A8IDht9RtEk7",
"rrHgbSZQfkauEi/mH3/6CDZoLqSHudUZ7d4MaJwun1TkFYGe2ORwGJd4OBj3oGJp",
"H8YBwCpk///L/fKjX0Gg3M8nrpM4wrRFhPKidAgO/kcm25X4+ZHlVkWBTCt5RWKI",
"fHh6oLDZCqCfcgMkE1KKmwfIHaUkhq5BPRigwy6i5dh1DM4+1UCLh3dxzVbqE9b9",
"61NB19nXdRtDA2sOUnj9ve6m/wEPyCb6/zBQZqvCBYb1/AjdXpUrFT+DbpfyxaXN",
"XfhDVb5mNqNM/IVj0V5fvTc6vOfYbzQtPm10H+FdWWfb+rJRfyC3MA2w2IqstFe3",
"w3bu2iE6CQvSqRvge+ZqLKt/NqYwOURiUmpuklbl3kPJ97+mfKWoiqk8Iz1VY+bb",
"NMUC7aoGv+jcoj+WS6PYO8N6BeRVUUB3ZJSf8nzjgxm1/BcM+UD3BPrlhT11ODRs",
"baifGbprMWwt3dhb8cQgRT8GPdpO1OsDkzL6iikMjLHWWiA99GV6ruiHsIPw6boW",
"A6/uSOskbDHOROotKmddGTBd0iiHXAoQsJFt1ZjUkt6EHrgWs+GAvrvKpXs1mrz8",
"uj3GwEFrHS+Xuf2UDgpszYT3hI2cL/kUtGakVR7m7vVMZqXBUbZdGAEb1PZNPwsI",
"E4aMK02+EVB+tSN4Fzj99N2YD0inVYt+oPjr2tHhUS6aSGBNS/48Ki47DOg4Sxkn",
"lkOWnEbCD+XTnbDd",
"=agR5",
"-----END PGP MESSAGE-----",
"",
"",
"--YFrteb74qSXmggbOxZL9dRnhymywAi--",
"",
"",
]
).encode()
)
assert not check_encrypted(
"\r\n".join(
[
"Subject: Message opened",
"From: <barbaz@c2.testrun.org>",
"To: <foobar@c2.testrun.org>",
"Date: Sun, 15 Oct 2023 16:43:25 +0000",
"Message-ID: <Mr.78MWtlV7RAi.goCFzBhCYfy@c2.testrun.org>",
"Auto-Submitted: auto-replied",
"Chat-Version: 1.0",
"MIME-Version: 1.0",
"Content-Type: multipart/report; report-type=disposition-notification;",
'\tboundary="Gl92xgZjOShJ5PGHntqYkoo2OK2Dvi"',
"",
"",
"--Gl92xgZjOShJ5PGHntqYkoo2OK2Dvi",
"Content-Type: text/plain; charset=utf-8; format=flowed; delsp=no",
"",
'The "Hi!" message you sent was displayed on the screen of the recipient.',
"",
"This is no guarantee the content was read.",
"",
"",
"--Gl92xgZjOShJ5PGHntqYkoo2OK2Dvi",
"Content-Type: message/disposition-notification",
"",
"Reporting-UA: Delta Chat 1.124.1",
"Original-Recipient: rfc822;barbaz@c2.testrun.org",
"Final-Recipient: rfc822;barbaz@c2.testrun.org",
"Original-Message-ID: <Mr.MvmCz-GQbi_.6FGRkhDf05c@c2.testrun.org>",
"Disposition: manual-action/MDN-sent-automatically; displayed",
"",
"",
"--Gl92xgZjOShJ5PGHntqYkoo2OK2Dvi--",
"",
"",
]
).encode()
)