Public bug reported: Using Mailman 2.1.33. I noticed that occasionally, DMARC mitigations for aol.com "From" addresses were not being applied.
I tracked us down to the fact that DNS records can in rare cases return "AOL" in uppercase in the answer of the TXT record lookup. Here's an example where I caught it happening: $ dig _dmarc.aol.com TXT [...] ;; QUESTION SECTION: ;_dmarc.aol.com. IN TXT ;; ANSWER SECTION: _dmarc.AOL.com. 492 IN TXT "v=DMARC1; p=reject; pct=100; rua=mailto:[email protected]; ruf=mailto:[email protected];"; Note that we requested "_dmarc.aol.com" in the question section, but got back "_dmarc.AOL.com" in the answer section. That case mismatch makes this code in Mailman/Utils.py skip the record: for name in want_names: if name not in results_by_name: continue I believe the solution is to lowercase the result after the lookup. Patch attached. ** Affects: mailman Importance: Undecided Status: New ** Tags: dmarc ** Patch added: "Lowercase DMARC TXT record label in answer section" https://bugs.launchpad.net/bugs/1881035/+attachment/5377571/+files/mailman-dmarc-lowercase.patch -- You received this bug notification because you are a member of Mailman Coders, which is subscribed to GNU Mailman. https://bugs.launchpad.net/bugs/1881035 Title: DMARC mitigation fails if TXT record name contains uppercase To manage notifications about this bug go to: https://bugs.launchpad.net/mailman/+bug/1881035/+subscriptions _______________________________________________ Mailman-coders mailing list -- [email protected] To unsubscribe send an email to [email protected] https://mail.python.org/mailman3/lists/mailman-coders.python.org/ Member address: [email protected]
