Do not allow smtp to access insecure files (#104972)

homeassistant/components/smtp/notify.py

@@ -8,6 +8,7 @@ from email.mime.text import MIMEText
 import email.utils
 import logging
 import os
+from pathlib import Path
 import smtplib
 
 import voluptuous as vol
@@ -193,10 +194,15 @@ class MailNotificationService(BaseNotificationService):
         if data := kwargs.get(ATTR_DATA):
             if ATTR_HTML in data:
                 msg = _build_html_msg(
-                    message, data[ATTR_HTML], images=data.get(ATTR_IMAGES, [])
+                    self.hass,
+                    message,
+                    data[ATTR_HTML],
+                    images=data.get(ATTR_IMAGES, []),
                 )
             else:
-                msg = _build_multipart_msg(message, images=data.get(ATTR_IMAGES, []))
+                msg = _build_multipart_msg(
+                    self.hass, message, images=data.get(ATTR_IMAGES, [])
+                )
         else:
             msg = _build_text_msg(message)
 
@@ -241,13 +247,21 @@ def _build_text_msg(message):
     return MIMEText(message)
 
 
-def _attach_file(atch_name, content_id=""):
+def _attach_file(hass, atch_name, content_id=""):
     """Create a message attachment.
 
     If MIMEImage is successful and content_id is passed (HTML), add images in-line.
     Otherwise add them as attachments.
     """
     try:
+        file_path = Path(atch_name).parent
+        if not hass.config.is_allowed_path(str(file_path)):
+            _LOGGER.warning(
+                "'%s' is not secure to load data from, ignoring attachment '%s'!",
+                file_path,
+                atch_name,
+            )
+            return
         with open(atch_name, "rb") as attachment_file:
             file_bytes = attachment_file.read()
     except FileNotFoundError:
@@ -277,22 +291,22 @@ def _attach_file(atch_name, content_id=""):
     return attachment
 
 
-def _build_multipart_msg(message, images):
+def _build_multipart_msg(hass, message, images):
     """Build Multipart message with images as attachments."""
-    _LOGGER.debug("Building multipart email with image attachment(s)")
+    _LOGGER.debug("Building multipart email with image attachme_build_html_msgnt(s)")
     msg = MIMEMultipart()
     body_txt = MIMEText(message)
     msg.attach(body_txt)
 
     for atch_name in images:
-        attachment = _attach_file(atch_name)
+        attachment = _attach_file(hass, atch_name)
         if attachment:
             msg.attach(attachment)
 
     return msg
 
 
-def _build_html_msg(text, html, images):
+def _build_html_msg(hass, text, html, images):
     """Build Multipart message with in-line images and rich HTML (UTF-8)."""
     _LOGGER.debug("Building HTML rich email")
     msg = MIMEMultipart("related")
@@ -303,7 +317,7 @@ def _build_html_msg(text, html, images):
 
     for atch_name in images:
         name = os.path.basename(atch_name)
-        attachment = _attach_file(atch_name, name)
+        attachment = _attach_file(hass, atch_name, name)
         if attachment:
             msg.attach(attachment)
     return msg

tests/components/smtp/test_notify.py

@@ -1,4 +1,5 @@
 """The tests for the notify smtp platform."""
+from pathlib import Path
 import re
 from unittest.mock import patch
 
@@ -132,15 +133,44 @@ EMAIL_DATA = [
     ],
 )
 def test_send_message(
-    message_data, data, content_type, hass: HomeAssistant, message
+    hass: HomeAssistant, message_data, data, content_type, message
 ) -> None:
     """Verify if we can send messages of all types correctly."""
     sample_email = "<mock@mock>"
+    message.hass = hass
+    hass.config.allowlist_external_dirs.add(Path("tests/testing_config").resolve())
     with patch("email.utils.make_msgid", return_value=sample_email):
         result, _ = message.send_message(message_data, data=data)
         assert content_type in result
 
 
+@pytest.mark.parametrize(
+    ("message_data", "data", "content_type"),
+    [
+        (
+            "Test msg",
+            {"images": ["tests/testing_config/notify/test.jpg"]},
+            "Content-Type: multipart/mixed",
+        ),
+    ],
+)
+def test_sending_insecure_files_fails(
+    hass: HomeAssistant,
+    caplog: pytest.LogCaptureFixture,
+    message_data,
+    data,
+    content_type,
+    message,
+) -> None:
+    """Verify if we cannot send messages with insecure attachments."""
+    sample_email = "<mock@mock>"
+    message.hass = hass
+    with patch("email.utils.make_msgid", return_value=sample_email):
+        result, _ = message.send_message(message_data, data=data)
+        assert content_type in result
+    assert "test.jpg' is not secure to load data from, ignoring attachment"
+
+
 def test_send_text_message(hass: HomeAssistant, message) -> None:
     """Verify if we can send simple text message."""
     expected = (