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postfix-3.9-20231221

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This commit is contained in:
Wietse Venema 2023-12-21 00:00:00 -05:00 committed by Viktor Dukhovni
parent a41effbfcb
commit dd0f14446a
11 changed files with 289 additions and 119 deletions
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19
postfix/HISTORY
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@ -27631,12 +27631,15 @@ Apologies for any names omitted.
cleanup/test-queue-file18, cleanup/cleanup_milter.in18[a-d],
cleanup/cleanup_milter.ref18[a-d][12].
20231219
20231221
Protocol enforcement: with "smtpd_forbid_bare_newline =
yes" (the default for Postfix 3.9), reply with "Error: bare
<LF> received" and disconnect when an SMTP client sends a
line ending in <LF>, violating the RFC 5321 requirement
that lines must end in <CR><LF>. Files: mantools/postlink,
proto/postconf.proto, global/mail_params.h, global/smtp_stream.c,
global/smtp_stream.h, smtpd/smtpd.c.
Security: with "smtpd_forbid_bare_newline = yes" (the default
for Postfix 3.9), reply with "Error: bare <LF> received"
and disconnect when an SMTP client sends a line ending in
<LF>, violating the RFC 5321 requirement that lines must
end in <CR><LF>. This prevents SMTP smuggling attacks that
target a recipient at a Postfix server. For backwards
compatibility, local clients are excluded by default with
"smtpd_forbid_bare_newline_exclusions = $mynetworks". Files:
mantools/postlink, proto/postconf.proto, global/mail_params.h,
global/smtp_stream.c, global/smtp_stream.h, smtpd/smtpd.c.

23
postfix/RELEASE_NOTES
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@ -26,6 +26,29 @@ now also distributed with the more recent Eclipse Public License
license of their choice. Those who are more comfortable with the
IPL can continue with that license.
Incompatible changes with snapshot 20231221
===========================================
Postfix 3.9 by default disconnects a client that sends a 'bare
newline' ending in SMTP. This prevents an SMTP smuggling attack
that targets recipients at a Postfix server. For background,
see https://www.postfix.org/smtp-smuggling.html
For compatibility with non-standard clients, Postfix 3.9 by default
excludes clients in mynetworks from this countermeasure.
The Postfix 3.9 default settings are:
# Disconnect remote SMTP clients that send bare newlines, but
# allow local clients with non-standard SMTP implementations
# such as netcat, fax machines, or load balancer health checks.
#
smtpd_forbid_bare_newline = yes
smtpd_forbid_bare_newline_exclusions = $mynetworks
This feature is back-ported to all supported stable releases, with
the difference that "smtpd_forbid_bare_newline = no" by default.
Incompatible changes with snapshot 20230903
===========================================

47
postfix/html/postconf.5.html
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@ -15927,10 +15927,49 @@ This feature is available in Postfix 2.0 and later.
<p> Reply with "Error: bare &lt;LF&gt; received" and disconnect
when a remote SMTP client sends a line ending in &lt;LF&gt;, violating
the <a href="https://tools.ietf.org/html/rfc5321">RFC 5321</a> requirement that lines must end in &lt;CR&gt;&lt;LF&gt;.
This feature is enabled by default with Postfix &ge; 3.9 but may
not work with non-standard clients such as netcat. Specify
"<a href="postconf.5.html#smtpd_forbid_bare_newline">smtpd_forbid_bare_newline</a> = no" to disable (not recommended for
an Internet-connected MTA). </p>
This feature is enabled by default with Postfix &ge; 3.9. Use
<a href="postconf.5.html#smtpd_forbid_bare_newline_exclusions">smtpd_forbid_bare_newline_exclusions</a> to exclude non-standard clients
such as netcat. Specify "<a href="postconf.5.html#smtpd_forbid_bare_newline">smtpd_forbid_bare_newline</a> = no" to disable
(not recommended for an Internet-connected MTA). </p>
<p> Example: </p>
<blockquote>
<pre>
# Disconnect remote SMTP clients that send bare newlines, but allow
# local clients with non-standard SMTP implementations such as netcat,
# fax machines, or load balancer health checks.
#
<a href="postconf.5.html#smtpd_forbid_bare_newline">smtpd_forbid_bare_newline</a> = yes
<a href="postconf.5.html#smtpd_forbid_bare_newline_exclusions">smtpd_forbid_bare_newline_exclusions</a> = $<a href="postconf.5.html#mynetworks">mynetworks</a>
</pre>
</blockquote>
<p> This feature is available in Postfix &ge; 3.9, 3.8.4, 3.7.9,
3.6.13, and 3.5.23. </p>
</DD>
<DT><b><a name="smtpd_forbid_bare_newline_exclusions">smtpd_forbid_bare_newline_exclusions</a>
(default: $<a href="postconf.5.html#mynetworks">mynetworks</a>)</b></DT><DD>
<p> Exclude the specified clients from <a href="postconf.5.html#smtpd_forbid_bare_newline">smtpd_forbid_bare_newline</a>
enforcement. It uses the same syntax and parent-domain matching
behavior as <a href="postconf.5.html#mynetworks">mynetworks</a>. </p>
<p> Example: </p>
<blockquote>
<pre>
# Disconnect remote SMTP clients that send bare newlines, but allow
# local clients with non-standard SMTP implementations such as netcat,
# fax machines, or load balancer health checks.
#
<a href="postconf.5.html#smtpd_forbid_bare_newline">smtpd_forbid_bare_newline</a> = yes
<a href="postconf.5.html#smtpd_forbid_bare_newline_exclusions">smtpd_forbid_bare_newline_exclusions</a> = $<a href="postconf.5.html#mynetworks">mynetworks</a>
</pre>
</blockquote>
<p> This feature is available in Postfix &ge; 3.9, 3.8.4, 3.7.9,
3.6.13, and 3.5.23. </p>

198
postfix/html/smtpd.8.html
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@ -1002,56 +1002,60 @@ SMTPD(8) SMTPD(8)
remote SMTP client sends a line ending in &lt;LF&gt;, violating the
<a href="https://tools.ietf.org/html/rfc5321">RFC 5321</a> requirement that lines must end in &lt;CR&gt;&lt;LF&gt;.
<b><a href="postconf.5.html#smtpd_forbid_bare_newline_exclusions">smtpd_forbid_bare_newline_exclusions</a> ($<a href="postconf.5.html#mynetworks">mynetworks</a>)</b>
Exclude the specified clients from <a href="postconf.5.html#smtpd_forbid_bare_newline">smtpd_forbid_bare_newline</a>
enforcement.
<b>TARPIT CONTROLS</b>
When a remote SMTP client makes errors, the Postfix SMTP server can
insert delays before responding. This can help to slow down run-away
software. The behavior is controlled by an error counter that counts
When a remote SMTP client makes errors, the Postfix SMTP server can
insert delays before responding. This can help to slow down run-away
software. The behavior is controlled by an error counter that counts
the number of errors within an SMTP session that a client makes without
delivering mail.
<b><a href="postconf.5.html#smtpd_error_sleep_time">smtpd_error_sleep_time</a> (1s)</b>
With Postfix version 2.1 and later: the SMTP server response
delay after a client has made more than $<a href="postconf.5.html#smtpd_soft_error_limit">smtpd_soft_error_limit</a>
errors, and fewer than $<a href="postconf.5.html#smtpd_hard_error_limit">smtpd_hard_error_limit</a> errors, without
With Postfix version 2.1 and later: the SMTP server response
delay after a client has made more than $<a href="postconf.5.html#smtpd_soft_error_limit">smtpd_soft_error_limit</a>
errors, and fewer than $<a href="postconf.5.html#smtpd_hard_error_limit">smtpd_hard_error_limit</a> errors, without
delivering mail.
<b><a href="postconf.5.html#smtpd_soft_error_limit">smtpd_soft_error_limit</a> (10)</b>
The number of errors a remote SMTP client is allowed to make
without delivering mail before the Postfix SMTP server slows
The number of errors a remote SMTP client is allowed to make
without delivering mail before the Postfix SMTP server slows
down all its responses.
<b><a href="postconf.5.html#smtpd_hard_error_limit">smtpd_hard_error_limit</a> (normal: 20, overload: 1)</b>
The maximal number of errors a remote SMTP client is allowed to
The maximal number of errors a remote SMTP client is allowed to
make without delivering mail.
<b><a href="postconf.5.html#smtpd_junk_command_limit">smtpd_junk_command_limit</a> (normal: 100, overload: 1)</b>
The number of junk commands (NOOP, VRFY, ETRN or RSET) that a
remote SMTP client can send before the Postfix SMTP server
The number of junk commands (NOOP, VRFY, ETRN or RSET) that a
remote SMTP client can send before the Postfix SMTP server
starts to increment the error counter with each junk command.
Available in Postfix version 2.1 and later:
<b><a href="postconf.5.html#smtpd_recipient_overshoot_limit">smtpd_recipient_overshoot_limit</a> (1000)</b>
The number of recipients that a remote SMTP client can send in
The number of recipients that a remote SMTP client can send in
excess of the limit specified with $<a href="postconf.5.html#smtpd_recipient_limit">smtpd_recipient_limit</a>,
before the Postfix SMTP server increments the per-session error
before the Postfix SMTP server increments the per-session error
count for each excess recipient.
<b>ACCESS POLICY DELEGATION CONTROLS</b>
As of version 2.1, Postfix can be configured to delegate access policy
decisions to an external server that runs outside Postfix. See the
As of version 2.1, Postfix can be configured to delegate access policy
decisions to an external server that runs outside Postfix. See the
file <a href="SMTPD_POLICY_README.html">SMTPD_POLICY_README</a> for more information.
<b><a href="postconf.5.html#smtpd_policy_service_max_idle">smtpd_policy_service_max_idle</a> (300s)</b>
The time after which an idle SMTPD policy service connection is
The time after which an idle SMTPD policy service connection is
closed.
<b><a href="postconf.5.html#smtpd_policy_service_max_ttl">smtpd_policy_service_max_ttl</a> (1000s)</b>
The time after which an active SMTPD policy service connection
The time after which an active SMTPD policy service connection
is closed.
<b><a href="postconf.5.html#smtpd_policy_service_timeout">smtpd_policy_service_timeout</a> (100s)</b>
The time limit for connecting to, writing to, or receiving from
The time limit for connecting to, writing to, or receiving from
a delegated SMTPD policy server.
Available in Postfix version 3.0 and later:
@ -1061,81 +1065,81 @@ SMTPD(8) SMTPD(8)
The default action when an SMTPD policy service request fails.
<b><a href="postconf.5.html#smtpd_policy_service_request_limit">smtpd_policy_service_request_limit</a> (0)</b>
The maximal number of requests per SMTPD policy service connec-
The maximal number of requests per SMTPD policy service connec-
tion, or zero (no limit).
<b><a href="postconf.5.html#smtpd_policy_service_try_limit">smtpd_policy_service_try_limit</a> (2)</b>
The maximal number of attempts to send an SMTPD policy service
The maximal number of attempts to send an SMTPD policy service
request before giving up.
<b><a href="postconf.5.html#smtpd_policy_service_retry_delay">smtpd_policy_service_retry_delay</a> (1s)</b>
The delay between attempts to resend a failed SMTPD policy ser-
The delay between attempts to resend a failed SMTPD policy ser-
vice request.
Available in Postfix version 3.1 and later:
<b><a href="postconf.5.html#smtpd_policy_service_policy_context">smtpd_policy_service_policy_context</a> (empty)</b>
Optional information that the Postfix SMTP server specifies in
the "policy_context" attribute of a policy service request
(originally, to share the same service endpoint among multiple
Optional information that the Postfix SMTP server specifies in
the "policy_context" attribute of a policy service request
(originally, to share the same service endpoint among multiple
<a href="postconf.5.html#check_policy_service">check_policy_service</a> clients).
<b>ACCESS CONTROLS</b>
The <a href="SMTPD_ACCESS_README.html">SMTPD_ACCESS_README</a> document gives an introduction to all the SMTP
The <a href="SMTPD_ACCESS_README.html">SMTPD_ACCESS_README</a> document gives an introduction to all the SMTP
server access control features.
<b><a href="postconf.5.html#smtpd_delay_reject">smtpd_delay_reject</a> (yes)</b>
Wait until the RCPT TO command before evaluating
Wait until the RCPT TO command before evaluating
$<a href="postconf.5.html#smtpd_client_restrictions">smtpd_client_restrictions</a>, $<a href="postconf.5.html#smtpd_helo_restrictions">smtpd_helo_restrictions</a> and
$<a href="postconf.5.html#smtpd_sender_restrictions">smtpd_sender_restrictions</a>, or wait until the ETRN command
before evaluating $<a href="postconf.5.html#smtpd_client_restrictions">smtpd_client_restrictions</a> and
before evaluating $<a href="postconf.5.html#smtpd_client_restrictions">smtpd_client_restrictions</a> and
$<a href="postconf.5.html#smtpd_helo_restrictions">smtpd_helo_restrictions</a>.
<b><a href="postconf.5.html#parent_domain_matches_subdomains">parent_domain_matches_subdomains</a> (see 'postconf -d' output)</b>
A list of Postfix features where the pattern "example.com" also
matches subdomains of example.com, instead of requiring an
A list of Postfix features where the pattern "example.com" also
matches subdomains of example.com, instead of requiring an
explicit ".example.com" pattern.
<b><a href="postconf.5.html#smtpd_client_restrictions">smtpd_client_restrictions</a> (empty)</b>
Optional restrictions that the Postfix SMTP server applies in
Optional restrictions that the Postfix SMTP server applies in
the context of a client connection request.
<b><a href="postconf.5.html#smtpd_helo_required">smtpd_helo_required</a> (no)</b>
Require that a remote SMTP client introduces itself with the
HELO or EHLO command before sending the MAIL command or other
Require that a remote SMTP client introduces itself with the
HELO or EHLO command before sending the MAIL command or other
commands that require EHLO negotiation.
<b><a href="postconf.5.html#smtpd_helo_restrictions">smtpd_helo_restrictions</a> (empty)</b>
Optional restrictions that the Postfix SMTP server applies in
Optional restrictions that the Postfix SMTP server applies in
the context of a client HELO command.
<b><a href="postconf.5.html#smtpd_sender_restrictions">smtpd_sender_restrictions</a> (empty)</b>
Optional restrictions that the Postfix SMTP server applies in
Optional restrictions that the Postfix SMTP server applies in
the context of a client MAIL FROM command.
<b><a href="postconf.5.html#smtpd_recipient_restrictions">smtpd_recipient_restrictions</a> (see 'postconf -d' output)</b>
Optional restrictions that the Postfix SMTP server applies in
the context of a client RCPT TO command, after
Optional restrictions that the Postfix SMTP server applies in
the context of a client RCPT TO command, after
<a href="postconf.5.html#smtpd_relay_restrictions">smtpd_relay_restrictions</a>.
<b><a href="postconf.5.html#smtpd_etrn_restrictions">smtpd_etrn_restrictions</a> (empty)</b>
Optional restrictions that the Postfix SMTP server applies in
Optional restrictions that the Postfix SMTP server applies in
the context of a client ETRN command.
<b><a href="postconf.5.html#allow_untrusted_routing">allow_untrusted_routing</a> (no)</b>
Forward mail with sender-specified routing
(user[@%!]remote[@%!]site) from untrusted clients to destina-
Forward mail with sender-specified routing
(user[@%!]remote[@%!]site) from untrusted clients to destina-
tions matching $<a href="postconf.5.html#relay_domains">relay_domains</a>.
<b><a href="postconf.5.html#smtpd_restriction_classes">smtpd_restriction_classes</a> (empty)</b>
User-defined aliases for groups of access restrictions.
<b><a href="postconf.5.html#smtpd_null_access_lookup_key">smtpd_null_access_lookup_key</a> (</b>&lt;&gt;<b>)</b>
The lookup key to be used in SMTP <a href="access.5.html"><b>access</b>(5)</a> tables instead of
The lookup key to be used in SMTP <a href="access.5.html"><b>access</b>(5)</a> tables instead of
the null sender address.
<b><a href="postconf.5.html#permit_mx_backup_networks">permit_mx_backup_networks</a> (empty)</b>
Restrict the use of the <a href="postconf.5.html#permit_mx_backup">permit_mx_backup</a> SMTP access feature to
Restrict the use of the <a href="postconf.5.html#permit_mx_backup">permit_mx_backup</a> SMTP access feature to
only domains whose primary MX hosts match the listed networks.
Available in Postfix version 2.0 and later:
@ -1145,19 +1149,19 @@ SMTPD(8) SMTPD(8)
applies in the context of the SMTP DATA command.
<b><a href="postconf.5.html#smtpd_expansion_filter">smtpd_expansion_filter</a> (see 'postconf -d' output)</b>
What characters are allowed in $name expansions of RBL reply
What characters are allowed in $name expansions of RBL reply
templates.
Available in Postfix version 2.1 and later:
<b><a href="postconf.5.html#smtpd_reject_unlisted_sender">smtpd_reject_unlisted_sender</a> (no)</b>
Request that the Postfix SMTP server rejects mail from unknown
sender addresses, even when no explicit <a href="postconf.5.html#reject_unlisted_sender">reject_unlisted_sender</a>
Request that the Postfix SMTP server rejects mail from unknown
sender addresses, even when no explicit <a href="postconf.5.html#reject_unlisted_sender">reject_unlisted_sender</a>
access restriction is specified.
<b><a href="postconf.5.html#smtpd_reject_unlisted_recipient">smtpd_reject_unlisted_recipient</a> (yes)</b>
Request that the Postfix SMTP server rejects mail for unknown
recipient addresses, even when no explicit
Request that the Postfix SMTP server rejects mail for unknown
recipient addresses, even when no explicit
<a href="postconf.5.html#reject_unlisted_recipient">reject_unlisted_recipient</a> access restriction is specified.
Available in Postfix version 2.2 and later:
@ -1171,17 +1175,17 @@ SMTPD(8) SMTPD(8)
<b><a href="postconf.5.html#smtpd_relay_restrictions">smtpd_relay_restrictions</a> (<a href="postconf.5.html#permit_mynetworks">permit_mynetworks</a>, <a href="postconf.5.html#permit_sasl_authenticated">permit_sasl_authenticated</a>,</b>
<b><a href="postconf.5.html#defer_unauth_destination">defer_unauth_destination</a>)</b>
Access restrictions for mail relay control that the Postfix SMTP
server applies in the context of the RCPT TO command, before
server applies in the context of the RCPT TO command, before
<a href="postconf.5.html#smtpd_recipient_restrictions">smtpd_recipient_restrictions</a>.
<b>SENDER AND RECIPIENT ADDRESS VERIFICATION CONTROLS</b>
Postfix version 2.1 introduces sender and recipient address verifica-
Postfix version 2.1 introduces sender and recipient address verifica-
tion. This feature is implemented by sending probe email messages that
are not actually delivered. This feature is requested via the
<a href="postconf.5.html#reject_unverified_sender">reject_unverified_sender</a> and <a href="postconf.5.html#reject_unverified_recipient">reject_unverified_recipient</a> access
restrictions. The status of verification probes is maintained by the
<a href="verify.8.html"><b>verify</b>(8)</a> server. See the file <a href="ADDRESS_VERIFICATION_README.html">ADDRESS_VERIFICATION_README</a> for infor-
mation about how to configure and operate the Postfix sender/recipient
<a href="postconf.5.html#reject_unverified_sender">reject_unverified_sender</a> and <a href="postconf.5.html#reject_unverified_recipient">reject_unverified_recipient</a> access
restrictions. The status of verification probes is maintained by the
<a href="verify.8.html"><b>verify</b>(8)</a> server. See the file <a href="ADDRESS_VERIFICATION_README.html">ADDRESS_VERIFICATION_README</a> for infor-
mation about how to configure and operate the Postfix sender/recipient
address verification service.
<b><a href="postconf.5.html#address_verify_poll_count">address_verify_poll_count</a> (normal: 3, overload: 1)</b>
@ -1193,7 +1197,7 @@ SMTPD(8) SMTPD(8)
fication request in progress.
<b><a href="postconf.5.html#address_verify_sender">address_verify_sender</a> ($<a href="postconf.5.html#double_bounce_sender">double_bounce_sender</a>)</b>
The sender address to use in address verification probes; prior
The sender address to use in address verification probes; prior
to Postfix 2.5 the default was "postmaster".
<b><a href="postconf.5.html#unverified_sender_reject_code">unverified_sender_reject_code</a> (450)</b>
@ -1201,18 +1205,18 @@ SMTPD(8) SMTPD(8)
address is rejected by the <a href="postconf.5.html#reject_unverified_sender">reject_unverified_sender</a> restriction.
<b><a href="postconf.5.html#unverified_recipient_reject_code">unverified_recipient_reject_code</a> (450)</b>
The numerical Postfix SMTP server response when a recipient
address is rejected by the <a href="postconf.5.html#reject_unverified_recipient">reject_unverified_recipient</a> restric-
The numerical Postfix SMTP server response when a recipient
address is rejected by the <a href="postconf.5.html#reject_unverified_recipient">reject_unverified_recipient</a> restric-
tion.
Available in Postfix version 2.6 and later:
<b><a href="postconf.5.html#unverified_sender_defer_code">unverified_sender_defer_code</a> (450)</b>
The numerical Postfix SMTP server response code when a sender
The numerical Postfix SMTP server response code when a sender
address probe fails due to a temporary error condition.
<b><a href="postconf.5.html#unverified_recipient_defer_code">unverified_recipient_defer_code</a> (450)</b>
The numerical Postfix SMTP server response when a recipient
The numerical Postfix SMTP server response when a recipient
address probe fails due to a temporary error condition.
<b><a href="postconf.5.html#unverified_sender_reject_reason">unverified_sender_reject_reason</a> (empty)</b>
@ -1224,17 +1228,17 @@ SMTPD(8) SMTPD(8)
<a href="postconf.5.html#reject_unverified_recipient">reject_unverified_recipient</a>.
<b><a href="postconf.5.html#unverified_sender_tempfail_action">unverified_sender_tempfail_action</a> ($<a href="postconf.5.html#reject_tempfail_action">reject_tempfail_action</a>)</b>
The Postfix SMTP server's action when <a href="postconf.5.html#reject_unverified_sender">reject_unverified_sender</a>
The Postfix SMTP server's action when <a href="postconf.5.html#reject_unverified_sender">reject_unverified_sender</a>
fails due to a temporary error condition.
<b><a href="postconf.5.html#unverified_recipient_tempfail_action">unverified_recipient_tempfail_action</a> ($<a href="postconf.5.html#reject_tempfail_action">reject_tempfail_action</a>)</b>
The Postfix SMTP server's action when <a href="postconf.5.html#reject_unverified_recipient">reject_unverified_recipi</a>-
The Postfix SMTP server's action when <a href="postconf.5.html#reject_unverified_recipient">reject_unverified_recipi</a>-
<a href="postconf.5.html#reject_unverified_recipient">ent</a> fails due to a temporary error condition.
Available with Postfix 2.9 and later:
<b><a href="postconf.5.html#address_verify_sender_ttl">address_verify_sender_ttl</a> (0s)</b>
The time between changes in the time-dependent portion of
The time between changes in the time-dependent portion of
address verification probe sender addresses.
<b>ACCESS CONTROL RESPONSES</b>
@ -1246,36 +1250,36 @@ SMTPD(8) SMTPD(8)
map "reject" action.
<b><a href="postconf.5.html#defer_code">defer_code</a> (450)</b>
The numerical Postfix SMTP server response code when a remote
The numerical Postfix SMTP server response code when a remote
SMTP client request is rejected by the "defer" restriction.
<b><a href="postconf.5.html#invalid_hostname_reject_code">invalid_hostname_reject_code</a> (501)</b>
The numerical Postfix SMTP server response code when the client
HELO or EHLO command parameter is rejected by the
The numerical Postfix SMTP server response code when the client
HELO or EHLO command parameter is rejected by the
<a href="postconf.5.html#reject_invalid_helo_hostname">reject_invalid_helo_hostname</a> restriction.
<b><a href="postconf.5.html#maps_rbl_reject_code">maps_rbl_reject_code</a> (554)</b>
The numerical Postfix SMTP server response code when a remote
SMTP client request is blocked by the <a href="postconf.5.html#reject_rbl_client">reject_rbl_client</a>,
The numerical Postfix SMTP server response code when a remote
SMTP client request is blocked by the <a href="postconf.5.html#reject_rbl_client">reject_rbl_client</a>,
<a href="postconf.5.html#reject_rhsbl_client">reject_rhsbl_client</a>, <a href="postconf.5.html#reject_rhsbl_reverse_client">reject_rhsbl_reverse_client</a>,
<a href="postconf.5.html#reject_rhsbl_sender">reject_rhsbl_sender</a> or <a href="postconf.5.html#reject_rhsbl_recipient">reject_rhsbl_recipient</a> restriction.
<b><a href="postconf.5.html#non_fqdn_reject_code">non_fqdn_reject_code</a> (504)</b>
The numerical Postfix SMTP server reply code when a client
request is rejected by the <a href="postconf.5.html#reject_non_fqdn_helo_hostname">reject_non_fqdn_helo_hostname</a>,
The numerical Postfix SMTP server reply code when a client
request is rejected by the <a href="postconf.5.html#reject_non_fqdn_helo_hostname">reject_non_fqdn_helo_hostname</a>,
<a href="postconf.5.html#reject_non_fqdn_sender">reject_non_fqdn_sender</a> or <a href="postconf.5.html#reject_non_fqdn_recipient">reject_non_fqdn_recipient</a> restriction.
<b><a href="postconf.5.html#plaintext_reject_code">plaintext_reject_code</a> (450)</b>
The numerical Postfix SMTP server response code when a request
The numerical Postfix SMTP server response code when a request
is rejected by the <b><a href="postconf.5.html#reject_plaintext_session">reject_plaintext_session</a></b> restriction.
<b><a href="postconf.5.html#reject_code">reject_code</a> (554)</b>
The numerical Postfix SMTP server response code when a remote
The numerical Postfix SMTP server response code when a remote
SMTP client request is rejected by the "reject" restriction.
<b><a href="postconf.5.html#relay_domains_reject_code">relay_domains_reject_code</a> (554)</b>
The numerical Postfix SMTP server response code when a client
request is rejected by the <a href="postconf.5.html#reject_unauth_destination">reject_unauth_destination</a> recipient
The numerical Postfix SMTP server response code when a client
request is rejected by the <a href="postconf.5.html#reject_unauth_destination">reject_unauth_destination</a> recipient
restriction.
<b><a href="postconf.5.html#unknown_address_reject_code">unknown_address_reject_code</a> (450)</b>
@ -1283,24 +1287,24 @@ SMTPD(8) SMTPD(8)
a sender or recipient address because its domain is unknown.
<b><a href="postconf.5.html#unknown_client_reject_code">unknown_client_reject_code</a> (450)</b>
The numerical Postfix SMTP server response code when a client
without valid address &lt;=&gt; name mapping is rejected by the
The numerical Postfix SMTP server response code when a client
without valid address &lt;=&gt; name mapping is rejected by the
<a href="postconf.5.html#reject_unknown_client_hostname">reject_unknown_client_hostname</a> restriction.
<b><a href="postconf.5.html#unknown_hostname_reject_code">unknown_hostname_reject_code</a> (450)</b>
The numerical Postfix SMTP server response code when the host-
name specified with the HELO or EHLO command is rejected by the
The numerical Postfix SMTP server response code when the host-
name specified with the HELO or EHLO command is rejected by the
<a href="postconf.5.html#reject_unknown_helo_hostname">reject_unknown_helo_hostname</a> restriction.
Available in Postfix version 2.0 and later:
<b><a href="postconf.5.html#default_rbl_reply">default_rbl_reply</a> (see 'postconf -d' output)</b>
The default Postfix SMTP server response template for a request
The default Postfix SMTP server response template for a request
that is rejected by an RBL-based restriction.
<b><a href="postconf.5.html#multi_recipient_bounce_reject_code">multi_recipient_bounce_reject_code</a> (550)</b>
The numerical Postfix SMTP server response code when a remote
SMTP client request is blocked by the <a href="postconf.5.html#reject_multi_recipient_bounce">reject_multi_recipi</a>-
The numerical Postfix SMTP server response code when a remote
SMTP client request is blocked by the <a href="postconf.5.html#reject_multi_recipient_bounce">reject_multi_recipi</a>-
<a href="postconf.5.html#reject_multi_recipient_bounce">ent_bounce</a> restriction.
<b><a href="postconf.5.html#rbl_reply_maps">rbl_reply_maps</a> (empty)</b>
@ -1310,52 +1314,52 @@ SMTPD(8) SMTPD(8)
<b><a href="postconf.5.html#access_map_defer_code">access_map_defer_code</a> (450)</b>
The numerical Postfix SMTP server response code for an <a href="access.5.html"><b>access</b>(5)</a>
map "defer" action, including "<a href="postconf.5.html#defer_if_permit">defer_if_permit</a>" or
map "defer" action, including "<a href="postconf.5.html#defer_if_permit">defer_if_permit</a>" or
"<a href="postconf.5.html#defer_if_reject">defer_if_reject</a>".
<b><a href="postconf.5.html#reject_tempfail_action">reject_tempfail_action</a> (<a href="postconf.5.html#defer_if_permit">defer_if_permit</a>)</b>
The Postfix SMTP server's action when a reject-type restriction
The Postfix SMTP server's action when a reject-type restriction
fails due to a temporary error condition.
<b><a href="postconf.5.html#unknown_helo_hostname_tempfail_action">unknown_helo_hostname_tempfail_action</a> ($<a href="postconf.5.html#reject_tempfail_action">reject_tempfail_action</a>)</b>
The Postfix SMTP server's action when <a href="postconf.5.html#reject_unknown_helo_hostname">reject_unknown_helo_host</a>-
The Postfix SMTP server's action when <a href="postconf.5.html#reject_unknown_helo_hostname">reject_unknown_helo_host</a>-
<a href="postconf.5.html#reject_unknown_helo_hostname">name</a> fails due to a temporary error condition.
<b><a href="postconf.5.html#unknown_address_tempfail_action">unknown_address_tempfail_action</a> ($<a href="postconf.5.html#reject_tempfail_action">reject_tempfail_action</a>)</b>
The Postfix SMTP server's action when
<a href="postconf.5.html#reject_unknown_sender_domain">reject_unknown_sender_domain</a> or <a href="postconf.5.html#reject_unknown_recipient_domain">reject_unknown_recipient_domain</a>
The Postfix SMTP server's action when
<a href="postconf.5.html#reject_unknown_sender_domain">reject_unknown_sender_domain</a> or <a href="postconf.5.html#reject_unknown_recipient_domain">reject_unknown_recipient_domain</a>
fail due to a temporary error condition.
<b>MISCELLANEOUS CONTROLS</b>
<b><a href="postconf.5.html#config_directory">config_directory</a> (see 'postconf -d' output)</b>
The default location of the Postfix <a href="postconf.5.html">main.cf</a> and <a href="master.5.html">master.cf</a> con-
The default location of the Postfix <a href="postconf.5.html">main.cf</a> and <a href="master.5.html">master.cf</a> con-
figuration files.
<b><a href="postconf.5.html#daemon_timeout">daemon_timeout</a> (18000s)</b>
How much time a Postfix daemon process may take to handle a
How much time a Postfix daemon process may take to handle a
request before it is terminated by a built-in watchdog timer.
<b><a href="postconf.5.html#command_directory">command_directory</a> (see 'postconf -d' output)</b>
The location of all postfix administrative commands.
<b><a href="postconf.5.html#double_bounce_sender">double_bounce_sender</a> (double-bounce)</b>
The sender address of postmaster notifications that are gener-
The sender address of postmaster notifications that are gener-
ated by the mail system.
<b><a href="postconf.5.html#ipc_timeout">ipc_timeout</a> (3600s)</b>
The time limit for sending or receiving information over an
The time limit for sending or receiving information over an
internal communication channel.
<b><a href="postconf.5.html#mail_name">mail_name</a> (Postfix)</b>
The mail system name that is displayed in Received: headers, in
The mail system name that is displayed in Received: headers, in
the SMTP greeting banner, and in bounced mail.
<b><a href="postconf.5.html#mail_owner">mail_owner</a> (postfix)</b>
The UNIX system account that owns the Postfix queue and most
The UNIX system account that owns the Postfix queue and most
Postfix daemon processes.
<b><a href="postconf.5.html#max_idle">max_idle</a> (100s)</b>
The maximum amount of time that an idle Postfix daemon process
The maximum amount of time that an idle Postfix daemon process
waits for an incoming connection before terminating voluntarily.
<b><a href="postconf.5.html#max_use">max_use</a> (100)</b>
@ -1366,11 +1370,11 @@ SMTPD(8) SMTPD(8)
The internet hostname of this mail system.
<b><a href="postconf.5.html#mynetworks">mynetworks</a> (see 'postconf -d' output)</b>
The list of "trusted" remote SMTP clients that have more privi-
The list of "trusted" remote SMTP clients that have more privi-
leges than "strangers".
<b><a href="postconf.5.html#myorigin">myorigin</a> ($<a href="postconf.5.html#myhostname">myhostname</a>)</b>
The domain name that locally-posted mail appears to come from,
The domain name that locally-posted mail appears to come from,
and that locally posted mail is delivered to.
<b><a href="postconf.5.html#process_id">process_id</a> (read-only)</b>
@ -1383,24 +1387,24 @@ SMTPD(8) SMTPD(8)
The location of the Postfix top-level queue directory.
<b><a href="postconf.5.html#recipient_delimiter">recipient_delimiter</a> (empty)</b>
The set of characters that can separate an email address local-
The set of characters that can separate an email address local-
part, user name, or a .forward file name from its extension.
<b><a href="postconf.5.html#smtpd_banner">smtpd_banner</a> ($<a href="postconf.5.html#myhostname">myhostname</a> ESMTP $<a href="postconf.5.html#mail_name">mail_name</a>)</b>
The text that follows the 220 status code in the SMTP greeting
The text that follows the 220 status code in the SMTP greeting
banner.
<b><a href="postconf.5.html#syslog_facility">syslog_facility</a> (mail)</b>
The syslog facility of Postfix logging.
<b><a href="postconf.5.html#syslog_name">syslog_name</a> (see 'postconf -d' output)</b>
A prefix that is prepended to the process name in syslog
A prefix that is prepended to the process name in syslog
records, so that, for example, "smtpd" becomes "prefix/smtpd".
Available in Postfix version 2.2 and later:
<b><a href="postconf.5.html#smtpd_forbidden_commands">smtpd_forbidden_commands</a> (CONNECT GET POST <a href="regexp_table.5.html">regexp</a>:{{/^[^A-Z]/ Bogus}})</b>
List of commands that cause the Postfix SMTP server to immedi-
List of commands that cause the Postfix SMTP server to immedi-
ately terminate the session with a 221 code.
Available in Postfix version 2.5 and later:
@ -1417,7 +1421,7 @@ SMTPD(8) SMTPD(8)
Available in Postfix 3.4 and later:
<b><a href="postconf.5.html#smtpd_reject_footer_maps">smtpd_reject_footer_maps</a> (empty)</b>
Lookup tables, indexed by the complete Postfix SMTP server 4xx
Lookup tables, indexed by the complete Postfix SMTP server 4xx
or 5xx response, with reject footer templates.
<b>SEE ALSO</b>

49
postfix/man/man5/postconf.5
View File

@ -11007,10 +11007,51 @@ This feature is available in Postfix 2.0 and later.
Reply with "Error: bare <LF> received" and disconnect
when a remote SMTP client sends a line ending in <LF>, violating
the RFC 5321 requirement that lines must end in <CR><LF>.
This feature is enabled by default with Postfix >= 3.9 but may
not work with non\-standard clients such as netcat. Specify
"smtpd_forbid_bare_newline = no" to disable (not recommended for
an Internet\-connected MTA).
This feature is enabled by default with Postfix >= 3.9. Use
smtpd_forbid_bare_newline_exclusions to exclude non\-standard clients
such as netcat. Specify "smtpd_forbid_bare_newline = no" to disable
(not recommended for an Internet\-connected MTA).
.PP
Example:
.sp
.in +4
.nf
.na
.ft C
# Disconnect remote SMTP clients that send bare newlines, but allow
# local clients with non\-standard SMTP implementations such as netcat,
# fax machines, or load balancer health checks.
#
smtpd_forbid_bare_newline = yes
smtpd_forbid_bare_newline_exclusions = $mynetworks
.fi
.ad
.ft R
.in -4
.PP
This feature is available in Postfix >= 3.9, 3.8.4, 3.7.9,
3.6.13, and 3.5.23.
.SH smtpd_forbid_bare_newline_exclusions (default: $mynetworks)
Exclude the specified clients from smtpd_forbid_bare_newline
enforcement. It uses the same syntax and parent\-domain matching
behavior as mynetworks.
.PP
Example:
.sp
.in +4
.nf
.na
.ft C
# Disconnect remote SMTP clients that send bare newlines, but allow
# local clients with non\-standard SMTP implementations such as netcat,
# fax machines, or load balancer health checks.
#
smtpd_forbid_bare_newline = yes
smtpd_forbid_bare_newline_exclusions = $mynetworks
.fi
.ad
.ft R
.in -4
.PP
This feature is available in Postfix >= 3.9, 3.8.4, 3.7.9,
3.6.13, and 3.5.23.

3
postfix/man/man8/smtpd.8
View File

@ -874,6 +874,9 @@ Available in Postfix 3.9, 3.8.3, 3.7.9, 3.6.13, 3.5.23 and later:
Reply with "Error: bare <LF> received" and disconnect
when a remote SMTP client sends a line ending in <LF>, violating
the RFC 5321 requirement that lines must end in <CR><LF>.
.IP "\fBsmtpd_forbid_bare_newline_exclusions ($mynetworks)\fR"
Exclude the specified clients from smtpd_forbid_bare_newline
enforcement.
.SH "TARPIT CONTROLS"
.na
.nf

1
postfix/mantools/postlink
View File

@ -562,6 +562,7 @@ while (<>) {
s;\bsmtpd_expansion_filter\b;<a href="postconf.5.html#smtpd_expansion_filter">$&</a>;g;
s;\bsmtpd_for[-</bB>]*\n*[ <bB>]*bidden_commands\b;<a href="postconf.5.html#smtpd_forbidden_commands">$&</a>;g;
s;\bsmtpd_for[-</bB>]*\n*[ <bB>]*bid_bare_newline\b;<a href="postconf.5.html#smtpd_forbid_bare_newline">$&</a>;g;
s;\bsmtpd_for[-</bB>]*\n*[ <bB>]*bid_bare_newline_exclusions\b;<a href="postconf.5.html#smtpd_forbid_bare_newline_exclusions">$&</a>;g;
s;\bsmtpd_for[-</bB>]*\n*[ <bB>]*bid_unauth_pipelining\b;<a href="postconf.5.html#smtpd_forbid_unauth_pipelining">$&</a>;g;
s;\bsmtpd_hard_error_limit\b;<a href="postconf.5.html#smtpd_hard_error_limit">$&</a>;g;
s;\bsmtpd_helo_required\b;<a href="postconf.5.html#smtpd_helo_required">$&</a>;g;

43
postfix/proto/postconf.proto
View File

@ -19060,10 +19060,45 @@ MinProtocol = TLSv1
<p> Reply with "Error: bare &lt;LF&gt; received" and disconnect
when a remote SMTP client sends a line ending in &lt;LF&gt;, violating
the RFC 5321 requirement that lines must end in &lt;CR&gt;&lt;LF&gt;.
This feature is enabled by default with Postfix &ge; 3.9 but may
not work with non-standard clients such as netcat. Specify
"smtpd_forbid_bare_newline = no" to disable (not recommended for
an Internet-connected MTA). </p>
This feature is enabled by default with Postfix &ge; 3.9. Use
smtpd_forbid_bare_newline_exclusions to exclude non-standard clients
such as netcat. Specify "smtpd_forbid_bare_newline = no" to disable
(not recommended for an Internet-connected MTA). </p>
<p> Example: </p>
<blockquote>
<pre>
# Disconnect remote SMTP clients that send bare newlines, but allow
# local clients with non-standard SMTP implementations such as netcat,
# fax machines, or load balancer health checks.
#
smtpd_forbid_bare_newline = yes
smtpd_forbid_bare_newline_exclusions = $mynetworks
</pre>
</blockquote>
<p> This feature is available in Postfix &ge; 3.9, 3.8.4, 3.7.9,
3.6.13, and 3.5.23. </p>
%PARAM smtpd_forbid_bare_newline_exclusions $mynetworks
<p> Exclude the specified clients from smtpd_forbid_bare_newline
enforcement. It uses the same syntax and parent-domain matching
behavior as mynetworks. </p>
<p> Example: </p>
<blockquote>
<pre>
# Disconnect remote SMTP clients that send bare newlines, but allow
# local clients with non-standard SMTP implementations such as netcat,
# fax machines, or load balancer health checks.
#
smtpd_forbid_bare_newline = yes
smtpd_forbid_bare_newline_exclusions = $mynetworks
</pre>
</blockquote>
<p> This feature is available in Postfix &ge; 3.9, 3.8.4, 3.7.9,
3.6.13, and 3.5.23. </p>

3
postfix/src/global/mail_params.h
View File

@ -4308,6 +4308,9 @@ extern char *var_smtpd_dns_re_filter;
#define VAR_SMTPD_FORBID_BARE_LF "smtpd_forbid_bare_newline"
#define DEF_SMTPD_FORBID_BARE_LF 1
#define VAR_SMTPD_FORBID_BARE_LF_EXCL "smtpd_forbid_bare_newline_exclusions"
#define DEF_SMTPD_FORBID_BARE_LF_EXCL "$" VAR_MYNETWORKS
/*
* Share TLS sessions through tlsproxy(8).
*/

2
postfix/src/global/mail_version.h
View File

@ -20,7 +20,7 @@
* Patches change both the patchlevel and the release date. Snapshots have no
* patchlevel; they change the release date only.
*/
#define MAIL_RELEASE_DATE "20231219"
#define MAIL_RELEASE_DATE "20231221"
#define MAIL_VERSION_NUMBER "3.9"
#ifdef SNAPSHOT

20
postfix/src/smtpd/smtpd.c
View File

@ -828,6 +828,9 @@
/* Reply with "Error: bare <LF> received" and disconnect
/* when a remote SMTP client sends a line ending in <LF>, violating
/* the RFC 5321 requirement that lines must end in <CR><LF>.
/* .IP "\fBsmtpd_forbid_bare_newline_exclusions ($mynetworks)\fR"
/* Exclude the specified clients from smtpd_forbid_bare_newline
/* enforcement.
/* TARPIT CONTROLS
/* .ad
/* .fi
@ -1539,6 +1542,9 @@ bool var_relay_before_rcpt_checks;
bool var_smtpd_req_deadline;
int var_smtpd_min_data_rate;
char *var_hfrom_format;
bool var_smtpd_forbid_bare_lf;
char *var_smtpd_forbid_bare_lf_excl;
static NAMADR_LIST *bare_lf_excl;
/*
* Silly little macros.
@ -6163,6 +6169,13 @@ static void smtpd_service(VSTREAM *stream, char *service, char **argv)
xforward_allowed = SMTPD_STAND_ALONE((&state)) == 0 &&
namadr_list_match(xforward_hosts, state.name, state.addr);
/*
* Enforce strict SMTP line endings, with compatibility exclusions.
*/
smtp_forbid_bare_lf = SMTPD_STAND_ALONE((&state)) == 0
&& var_smtpd_forbid_bare_lf
&& !namadr_list_match(bare_lf_excl, state.name, state.addr);
/*
* See if we need to turn on verbose logging for this client.
*/
@ -6224,6 +6237,10 @@ static void pre_jail_init(char *unused_name, char **unused_argv)
hogger_list = namadr_list_init(VAR_SMTPD_HOGGERS, MATCH_FLAG_RETURN
| match_parent_style(VAR_SMTPD_HOGGERS),
var_smtpd_hoggers);
bare_lf_excl = namadr_list_init(VAR_SMTPD_FORBID_BARE_LF_EXCL,
MATCH_FLAG_RETURN
| match_parent_style(VAR_MYNETWORKS),
var_smtpd_forbid_bare_lf_excl);
/*
* Open maps before dropping privileges so we can read passwords etc.
@ -6590,7 +6607,7 @@ int main(int argc, char **argv)
VAR_SMTPD_DELAY_OPEN, DEF_SMTPD_DELAY_OPEN, &var_smtpd_delay_open,
VAR_SMTPD_CLIENT_PORT_LOG, DEF_SMTPD_CLIENT_PORT_LOG, &var_smtpd_client_port_log,
VAR_SMTPD_FORBID_UNAUTH_PIPE, DEF_SMTPD_FORBID_UNAUTH_PIPE, &var_smtpd_forbid_unauth_pipe,
VAR_SMTPD_FORBID_BARE_LF, DEF_SMTPD_FORBID_BARE_LF, &smtp_forbid_bare_lf,
VAR_SMTPD_FORBID_BARE_LF, DEF_SMTPD_FORBID_BARE_LF, &var_smtpd_forbid_bare_lf,
0,
};
static const CONFIG_NBOOL_TABLE nbool_table[] = {
@ -6707,6 +6724,7 @@ int main(int argc, char **argv)
VAR_SMTPD_DNS_RE_FILTER, DEF_SMTPD_DNS_RE_FILTER, &var_smtpd_dns_re_filter, 0, 0,
VAR_SMTPD_REJ_FTR_MAPS, DEF_SMTPD_REJ_FTR_MAPS, &var_smtpd_rej_ftr_maps, 0, 0,
VAR_HFROM_FORMAT, DEF_HFROM_FORMAT, &var_hfrom_format, 1, 0,
VAR_SMTPD_FORBID_BARE_LF_EXCL, DEF_SMTPD_FORBID_BARE_LF_EXCL, &var_smtpd_forbid_bare_lf_excl, 0, 0,
0,
};
static const CONFIG_RAW_TABLE raw_table[] = {