postfix-3.7.0

[Bruce Dubbs]

New minor version.

[Bruce Dubbs]

This is the Postfix 3.7 (stable) release.

The stable Postfix release is called postfix-3.7.x where 3=major release number, 7=minor release number, x=patchlevel. The stable release never changes except for patches that address bugs or emergencies. Patches change the patchlevel and the release date.

New features are developed in snapshot releases. These are called postfix-3.8-yyyymmdd where yyyymmdd is the release date (yyyy=year, mm=month, dd=day). Patches are never issued for snapshot releases; instead, a new snapshot is released.

The mail_release_date configuration parameter (format: yyyymmdd) specifies the release date of a stable release or snapshot release.

If you upgrade from Postfix 3.5 or earlier, read RELEASE_NOTES-3.6 before proceeding.

License change

This software is distributed with a dual license: in addition to the historical IBM Public License 1.0, it is now also distributed with the more recent Eclipse Public License 2.0. Recipients can choose to take the software under the license of their choice. Those who are more comfortable with the IPL can continue with that license.

Major changes - configuration

• [Feature 20210605] Support to inline the content of small cidr:, pcre:, and regexp: tables in Postfix parameter values.

Major changes - lmdb support

• [Feature 20210605] Overhauled the LMDB client's error handling, and added integration tests for future-proofing. There are no visible changes in documented behavior.

Major changes - logging

• Feature 20211127] Support for the pcre2 library (the legacy pcre library is no longer maintained). The Postfix build procedure automatically detects if the pcre2 library is installed, and if it is unavailable, the Postfix build procedure will detect if the legacy pcre library is installed. See PCRE_README if you need to build Postfix with a specific library.

Major changes - security

• [Feature 20220102] Postfix programs now randomize the initial state of in-memory hash tables, to defend against hash collision attacks involving a large number of attacker-chosen lookup keys. Presently, the only known opportunity for such attacks involves remote SMTP client IPv6 addresses in the anvil(8) service. The attack would require making hundreds of short-lived connections per second from thousands of different IP addresses, because the anvil(8) service drops inactive counters after 100s. Other in-memory hash tables with attacker-chosen lookup keys are by design limited in size. The fix is cheap, and therefore implemented for all Postfix in-memory hash tables.

• [Feature 20211030] The postqueue command now sanitizes non-printable characters (such as newlines) in strings before they are formatted as json or as legacy output. These outputs are piped into other programs that are run by administrative users. This closes a hypothetical opportunity for privilege escalation.

• [Feature 20210815] Updated defense against remote clients or servers that 'trickle' SMTP or LMTP traffic, based on per-request deadlines and minimum data rates.

Per-request deadlines:

• The new {smtpd,smtp,lmtp}_per_request_deadline parameters replace {smtpd,smtp,lmtp}_per_record_deadline, with backwards compatible default settings. This defense is enabled by default in the Postfix SMTP server in case of overload.

• The new smtpd_per_record_deadline parameter limits the combined time for the Postfix SMTP server to receive a request and to send a response, while the new {smtp,lmtp}_per_record_deadline parameters limit the combined time for the Postfix SMTP or LMTP client to send a request and to receive a response.

Minimum data rates:

• The new smtpd_min_data_rate parameter enforces a minimum plaintext data transfer rate for DATA and BDAT requests, but only when smtpd_per_record_deadline is enabled. After a read operation transfers N plaintext bytes (possibly after TLS decryption), and after the DATA or BDAT request deadline is decreased by the elapsed time of that read operation, the DATA or BDAT request deadline is increased by N/smtpd_min_data_rate seconds. However, the deadline is never increased beyond the smtpd_timeout value. The default minimum data rate is 500 (bytes/second) but is still subject to change.

• The new {smtp,lmtp}_min_data_rate parameters enforce the corresponding minimum DATA transfer rates for the Postfix SMTP and LMTP client.

Major changes - tls support

• [Cleanup 20220121] The new tlsproxy_client_security_level parameter replaces tlsproxy_client_level, and the new tlsproxy_client_policy_maps parameter replaces tlsproxy_client_policy. This is for consistent parameter naming (tlsproxy_client_xxx corresponds to smtp_tls_xxx). This change was made with backwards-compatible default settings.

• [Feature 20210926] Postfix was updated to support OpenSSL 3.0.0 API features, and to work around OpenSSL 3.0.0 bit-rot (avoid using deprecated API features).

Other code health

• [typos] Typo fixes by

• [pre-release checks] Added pre-release checks to detect a) new typos in documentation and source-code comments, b) missing entries in the postfix-files file (some documentation would not be installed), c) missing rules in the postlink script (some text would not have a hyperlink in documentation), and d) missing map-based $parameter names in the proxy_read_maps default value (the proxymap daemon would not automatically authorize some proxied maps).

• [memory stream] Improved support for memory-based streams made it possible to inline small cidr:, pcre:, and regexp: maps in Postfix parameter values, and to eliminate some ad-hoc code that converted tlsproxy(8) protocol data to or from serialized form.

[Bruce Dubbs]

Fixed at revision 9fc3125db6dff495e7f76c6f23b66385840e7f20

Package updates and a typo.
    Update to harfbuzz-3.3.2.
    Update to ed-1.18.
    Update to postfix-3.7.0.
    Update to libreoffice-7.3.0.3.
    Update to inkscape-1.1.2.
    Fix typo in vim.