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Phase 2g of the DLP and mail flow rules spec: transport rules now act,
on outgoing and incoming mail.
- features/mailflow/rewrite.rs: add or remove a header, prefix or set the
subject (an RFC 2047 word when not ASCII), add a disclaimer. A
disclaimer edits the message's main text and HTML bodies only, each
decoded, changed and written back as UTF-8 quoted-printable with its
other headers kept, top or bottom (after <body> or before </body> in
HTML); attachments and attached messages are left alone, and a
disclaimer already present isn't added again.
- smtp/inbound/mailflow.rs: the check runs for incoming mail too
(transport rules only; DLP stays outgoing). After DLP passes, each
matched transport rule's actions run in order: message edits,
add-recipient and redirect (envelope changes DATA applies), route (a
per-message queue ahead of the queue strategy), refuse (550 5.7.1
with the rule's text). The override tag is stripped with the same
subject writer, so a non-ASCII subject stays valid.
- Audit: refusals and changes to where mail goes are recorded (sender,
or system:mail-flow for incoming mail); wording and header changes
aren't, or a banner rule would record every message (spec §2.7).
Tests: rewrite unit tests (headers, encoded subjects, disclaimers on a
single part and on multipart/alternative with an attachment, once
only); mail_rules_tests gains the actions end to end: disclaimer,
header and subject prefix on a delivered message, a redirect, a
refusal, a banner on incoming LMTP mail that outgoing rules leave
alone, and which of those are audited.
Phase 2f of the DLP and mail flow rules spec: the rules now run on mail
an authenticated sender submits, after the DATA system script and
before headers and DKIM signing (§2.1).
- smtp/inbound/mailflow.rs: builds what the rules look at from the
message (subject, the text version of each body, one level of attached
messages, attachment text via the extractor, 10 MB of text at most)
and the envelope (sender's groups and tenant; each recipient local or
not, and its groups). Skipped entirely when no enabled rule applies to
outgoing mail. Rules that can't be loaded refuse with a 451: nothing
unchecked leaves.
- Block: 550 5.7.1 with the rule's notice. Warn: 550 5.7.1 with the
notice and how to override: "[override: reason]" at the start of the
subject, taken out before the message goes on (settled answer 1).
Until phase 3, a hold rule blocks rather than let mail through.
- JMAP: EmailSubmission takes inbuxa:dlpOverride {reason}; a refusal
comes back as inbuxa:dlpWarning or inbuxa:dlpBlocked with each rule's
name and notice (description too, for older clients).
- Audit: one record per DLP match, the sender as actor, action create,
target a message: the recipient domains, each rule with its detectors'
counts, the outcome, an override's reason. Never the matched text. No
new audit action: an older node that meets one fails its daily
clean-up, which would make rolling back unsafe (spec §2.7 updated).
Tests: mail_rules_tests gains the DLP flow over JMAP (no rules, warning
with rule and notice, local recipient not warned, override with a
reason, block that no reason passes, the subject tag stripped from the
delivered message, audit records with no card or key text). smtp
inbound tests pass; system_tests passed twice after one timeout in the
email delivery tests that didn't recur.
Phase 2b of the DLP and mail flow rules spec: every identifier in the
§2.3 catalog, each implemented from its issuer's published rules and
tested against published examples.
US (SSN, ITIN, EIN, ABA routing, driver's licenses, MBI, NPI, DEA), UK
(NI number, NHS number, UTR), Canada (SIN), Australia (TFN, Medicare),
the EU (Germany's tax ID and ID card, France's NIR, Spain's DNI/NIE,
Italy's codice fiscale, the Dutch BSN, Belgium's national number,
Poland's PESEL, Sweden's personnummer, Denmark's CPR, Finland's HETU,
Ireland's PPS, Portugal's NIF, Austria's SVNR), Norway, Switzerland,
India (Aadhaar, PAN), China, Japan, Singapore, South Korea, Brazil (CPF,
CNPJ), Mexico (CURP) and South Africa. 49 detectors in all, plus seven
templates named for what they find.
An identifier that is only digits and whose check about one random
number in ten passes counts alone only in its written form
(536-22-1234, 943 476 5919) and as bare digits only beside a word; ABA
routing numbers and NPIs always need one. Spec §2.3 records this.
A test runs every detector over an ordinary business email (order,
invoice and tracking numbers, dates, amounts, an address) and requires
nothing to fire but the contact detectors. 47 unit tests.
All six settled as recommended. Answer 6 ("and any other recognized and protected PII") becomes a catalog of identifiers with published formats and checks, grouped by region, each either checked by its check digit or counted only beside a corroborating word, plus templates named for what they find. Data with no number to find is covered by word lists and not claimed as detection. Office documents are read; PDF counts as can't be inspected.
Phase 1: one native rule engine at DATA, after the system Sieve script,
for both DLP policies and transport rules. DLP checks outgoing mail
with counted detectors (payment cards, IBAN, US SSN, word lists,
patterns) and blocks, warns with an audited override, or holds for
review. Held mail stays in the queue unscheduled, with its own review
record, so the queue's stored format is unchanged. Matches go to the
audit log without the matched text. Six questions for John at the end.
jcoffey-dev