use user.max_spam_score if present

app/email_utils.py

@@ -464,7 +464,7 @@ def get_addrs_from_header(msg: Message, header) -> [str]:
     return [r for r in ret if r]
 
 
-def get_spam_info(msg: Message) -> (bool, str):
+def get_spam_info(msg: Message, max_score=None) -> (bool, str):
     """parse SpamAssassin header to detect whether a message is classified as spam.
     Return (is spam, spam status detail)
     The header format is
@@ -476,10 +476,31 @@ def get_spam_info(msg: Message) -> (bool, str):
     if not spamassassin_status:
         return False, ""
 
-    # yes or no
-    spamassassin_answer = spamassassin_status[: spamassassin_status.find(",")]
+    return get_spam_from_header(spamassassin_status, max_score=max_score)
 
-    return spamassassin_answer.lower() == "yes", spamassassin_status
+
+def get_spam_from_header(spam_status_header, max_score=None) -> (bool, str):
+    """get spam info from X-Spam-Status header
+    Return (is spam, spam status detail).
+    The spam_status_header has the following format
+    ```No, score=-0.1 required=5.0 tests=DKIM_SIGNED,DKIM_VALID,
+  DKIM_VALID_AU,RCVD_IN_DNSWL_BLOCKED,RCVD_IN_MSPIKE_H2,SPF_PASS,
+  URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.2```
+    """
+    # yes or no
+    spamassassin_answer = spam_status_header[: spam_status_header.find(",")]
+
+    if max_score:
+        # spam score
+        # get the score section "score=-0.1"
+        score_section = (
+            spam_status_header[spam_status_header.find(",") + 1 :].strip().split(" ")[0]
+        )
+        score = float(score_section[len("score=") :])
+        if score >= max_score:
+            return True, spam_status_header
+
+    return spamassassin_answer.lower() == "yes", spam_status_header
 
 
 def parseaddr_unicode(addr) -> (str, str):

email_handler.py

@@ -421,7 +421,7 @@ def forward_email_to_mailbox(
         )
         return False, "550 SL E14"
 
-    is_spam, spam_status = get_spam_info(msg)
+    is_spam, spam_status = get_spam_info(msg, max_score=user.max_spam_score)
     if is_spam:
         LOG.warning("Email detected as spam. Alias: %s, from: %s", alias, contact)
         email_log.is_spam = True

tests/test_email_utils.py

@@ -11,6 +11,7 @@ from app.email_utils import (
     parseaddr_unicode,
     send_email_with_rate_control,
     copy,
+    get_spam_from_header,
 )
 from app.extensions import db
 from app.models import User, CustomDomain
@@ -134,3 +135,28 @@ def test_copy():
     msg2 = copy(msg)
 
     assert msg.as_bytes() == msg2.as_bytes()
+
+
+def test_get_spam_from_header():
+    is_spam, _ = get_spam_from_header(
+        """No, score=-0.1 required=5.0 tests=DKIM_SIGNED,DKIM_VALID,
+  DKIM_VALID_AU,RCVD_IN_DNSWL_BLOCKED,RCVD_IN_MSPIKE_H2,SPF_PASS,
+  URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.2"""
+    )
+    assert not is_spam
+
+    is_spam, _ = get_spam_from_header(
+        """Yes, score=-0.1 required=5.0 tests=DKIM_SIGNED,DKIM_VALID,
+  DKIM_VALID_AU,RCVD_IN_DNSWL_BLOCKED,RCVD_IN_MSPIKE_H2,SPF_PASS,
+  URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.2"""
+    )
+    assert is_spam
+
+    # the case where max_score is less than the default used by SpamAssassin
+    is_spam, _ = get_spam_from_header(
+        """No, score=6 required=10.0 tests=DKIM_SIGNED,DKIM_VALID,
+  DKIM_VALID_AU,RCVD_IN_DNSWL_BLOCKED,RCVD_IN_MSPIKE_H2,SPF_PASS,
+  URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.2""",
+        max_score=5,
+    )
+    assert is_spam