infrastructure/mox
1
0
Fork 0
mirror of https://github.com/mjl-/mox.git synced 2025-07-13 08:14:37 +03:00
Code Issues Packages Projects Releases Wiki Activity

implement "requiretls", rfc 8689

Browse Source 
with requiretls, the tls verification mode/rules for email deliveries can be
changed by the sender/submitter. in two ways:

1. "requiretls" smtp extension to always enforce verified tls (with mta-sts or
dnssec+dane), along the entire delivery path until delivery into the final
destination mailbox (so entire transport is verified-tls-protected).

2. "tls-required: no" message header, to ignore any tls and tls verification
errors even if the recipient domain has a policy that requires tls verification
(mta-sts and/or dnssec+dane), allowing delivery of non-sensitive messages in
case of misconfiguration/interoperability issues (at least useful for sending
tls reports).

we enable requiretls by default (only when tls is active), for smtp and
submission. it can be disabled through the config.

for each delivery attempt, we now store (per recipient domain, in the account
of the sender) whether the smtp server supports starttls and requiretls. this
support is shown (after having sent a first message) in the webmail when
sending a message (the previous 3 bars under the address input field are now 5
bars, the first for starttls support, the last for requiretls support). when
all recipient domains for a message are known to implement requiretls,
requiretls is automatically selected for sending (instead of "default" tls
behaviour). users can also select the "fallback to insecure" to add the
"tls-required: no" header.

new metrics are added for insight into requiretls errors and (some, not yet
all) cases where tls-required-no ignored a tls/verification error.

the admin can change the requiretls status for messages in the queue. so with
default delivery attempts, when verified tls is required by failing, an admin
could potentially change the field to "tls-required: no"-behaviour.

messages received (over smtp) with the requiretls option, get a comment added
to their Received header line, just before "id", after "with".
This commit is contained in:
Mechiel Lukkien
2023-10-24 10:06:16 +02:00
parent 0e5e16b3d0
commit 2f5d6069bf
31 changed files with 1102 additions and 274 deletions
Download Patch File Download Diff File Expand all files Collapse all files

11
queue/dsn.go
View File

@ -15,7 +15,7 @@ import (
"github.com/mjl-/mox/store"
)
func queueDSNFailure(log *mlog.Log, m Msg, remoteMTA dsn.NameIP, secodeOpt, errmsg string) {
func deliverDSNFailure(log *mlog.Log, m Msg, remoteMTA dsn.NameIP, secodeOpt, errmsg string) {
const subject = "mail delivery failed"
message := fmt.Sprintf(`
Delivery has failed permanently for your email to:
@ -29,10 +29,10 @@ Error during the last delivery attempt:
%s
`, m.Recipient().XString(m.SMTPUTF8), errmsg)
queueDSN(log, m, remoteMTA, secodeOpt, errmsg, true, nil, subject, message)
deliverDSN(log, m, remoteMTA, secodeOpt, errmsg, true, nil, subject, message)
}
func queueDSNDelay(log *mlog.Log, m Msg, remoteMTA dsn.NameIP, secodeOpt, errmsg string, retryUntil time.Time) {
func deliverDSNDelay(log *mlog.Log, m Msg, remoteMTA dsn.NameIP, secodeOpt, errmsg string, retryUntil time.Time) {
const subject = "mail delivery delayed"
message := fmt.Sprintf(`
Delivery has been delayed of your email to:
@ -47,15 +47,14 @@ Error during the last delivery attempt:
%s
`, m.Recipient().XString(false), errmsg)
queueDSN(log, m, remoteMTA, secodeOpt, errmsg, false, &retryUntil, subject, message)
deliverDSN(log, m, remoteMTA, secodeOpt, errmsg, false, &retryUntil, subject, message)
}
// We only queue DSNs for delivery failures for emails submitted by authenticated
// users. So we are delivering to local users. ../rfc/5321:1466
// ../rfc/5321:1494
// ../rfc/7208:490
// todo future: when we implement relaying, we should be able to send DSNs to non-local users. and possibly specify a null mailfrom. ../rfc/5321:1503
func queueDSN(log *mlog.Log, m Msg, remoteMTA dsn.NameIP, secodeOpt, errmsg string, permanent bool, retryUntil *time.Time, subject, textBody string) {
func deliverDSN(log *mlog.Log, m Msg, remoteMTA dsn.NameIP, secodeOpt, errmsg string, permanent bool, retryUntil *time.Time, subject, textBody string) {
kind := "delayed delivery"
if permanent {
kind = "failure"