When following a CNAME chain, if any lookup is insecure the whole must be too

[exim.git] / src / README.UPDATING

diff --git a/src/README.UPDATING b/src/README.UPDATING
index 7ce35dff83a7d75a9f9ccbdb9e6d0a77e7290b9b..590642f3e569e2047f8b4dbe66e4a8059ef4d120 100644 (file)
--- a/src/README.UPDATING
+++ b/src/README.UPDATING
@@ -26,11 +26,42 @@ The rest of this document contains information about changes in 4.xx releases
 that might affect a running system.
 
 
 that might affect a running system.
 
 

+Exim version 4.83
+-----------------
+
+ * SPF condition results renamed "permerror" and "temperror".  The old
+   names are still accepted for back-compatability, for this release.
+
+ * TLS details are now logged on rejects, subject to log selectors.
+
+ * Items in headers_remove lists must now have any embedded list-separators
+   doubled.
+
+ * Attempted use of the deprecated options "gnutls_require_kx" et. al.
+   now result in logged warning.
+
+
+Exim version 4.82
+-----------------
+
+ * New option gnutls_allow_auto_pkcs11 defaults false; if you have GnuTLS 2.12.0
+   or later and do want PKCS11 modules to be autoloaded, then set this option.
+
+ * A per-transport wait-<name> database is no longer updated if the transport
+   sets "connection_max_messages" to 1, as it can not be used and causes
+   unnecessary serialisation and load.  External tools tracking the state of
+   Exim by the hints databases may need modification to take this into account.
+
+ * The av_scanner option can now accept multiple clamd TCP targets, all other
+   setting limitations remain.
+
+

 Exim version 4.80
 -----------------
 
  * BEWARE backwards-incompatible changes in SSL libraries, thus the version
    bump.  See points below for details.
 Exim version 4.80
 -----------------
 
  * BEWARE backwards-incompatible changes in SSL libraries, thus the version
    bump.  See points below for details.

+   Also an LDAP data returned format change.

 
  * The value of $tls_peerdn is now print-escaped when written to the spool file
    in a -tls_peerdn line, and unescaped when read back in.  We received reports
 
  * The value of $tls_peerdn is now print-escaped when written to the spool file
    in a -tls_peerdn line, and unescaped when read back in.  We received reports


@@ -42,6 +73,12 @@ Exim version 4.80
    the message.  No tool has been provided as we believe this is a rare
    occurence.
 
    the message.  No tool has been provided as we believe this is a rare
    occurence.
 

+ * For OpenSSL, SSLv2 is now disabled by default.  (GnuTLS does not support
+   SSLv2).  RFC 6176 prohibits SSLv2 and some informal surveys suggest no
+   actual usage.  You can re-enable with the "openssl_options" Exim option,
+   in the main configuration section.  Note that supporting SSLv2 exposes
+   you to ciphersuite downgrade attacks.
+

  * With OpenSSL 1.0.1+, Exim now supports TLS 1.1 and TLS 1.2.  If built
    against 1.0.1a then you will get a warning message and the
    "openssl_options" value will not parse "no_tlsv1_1": the value changes
  * With OpenSSL 1.0.1+, Exim now supports TLS 1.1 and TLS 1.2.  If built
    against 1.0.1a then you will get a warning message and the
    "openssl_options" value will not parse "no_tlsv1_1": the value changes


@@ -51,8 +88,9 @@ Exim version 4.80
    "openssl_options" gains "no_tlsv1_1", "no_tlsv1_2" and "no_compression".
 
    COMPATIBILITY WARNING: The default value of "openssl_options" is no longer
    "openssl_options" gains "no_tlsv1_1", "no_tlsv1_2" and "no_compression".
 
    COMPATIBILITY WARNING: The default value of "openssl_options" is no longer

-   "+dont_insert_empty_fragments".  We default to unset.  That old default was
-   grandfathered in from before openssl_options became a configuration option.
+   "+dont_insert_empty_fragments".  We default to "+no_sslv2".
+   That old default was grandfathered in from before openssl_options became a
+   configuration option.

    Empty fragments are inserted by default through TLS1.0, to partially defend
    against certain attacks; TLS1.1+ change the protocol so that this is not
    needed.  The DIEF SSL option was required for some old releases of mail
    Empty fragments are inserted by default through TLS1.0, to partially defend
    against certain attacks; TLS1.1+ change the protocol so that this is not
    needed.  The DIEF SSL option was required for some old releases of mail


@@ -66,12 +104,23 @@ Exim version 4.80
    security for compatibility.  Exim is now defaulting to higher security and
    rewarding more modern clients.
 
    security for compatibility.  Exim is now defaulting to higher security and
    rewarding more modern clients.
 

+   If the option tls_dhparams is set and the parameters loaded from the file
+   have a bit-count greater than the new option tls_dh_max_bits, then the file
+   will now be ignored.  If this affects you, raise the tls_dh_max_bits limit.
+   We suspect that most folks are using dated defaults and will not be affected.
+

  * Ldap lookups returning multi-valued attributes now separate the attributes
    with only a comma, not a comma-space sequence.  Also, an actual comma within
    a returned attribute is doubled.  This makes it possible to parse the
    attribute as a comma-separated list.  Note the distinction from multiple
    attributes being returned, where each one is a name=value pair.
 
  * Ldap lookups returning multi-valued attributes now separate the attributes
    with only a comma, not a comma-space sequence.  Also, an actual comma within
    a returned attribute is doubled.  This makes it possible to parse the
    attribute as a comma-separated list.  Note the distinction from multiple
    attributes being returned, where each one is a name=value pair.
 

+   If you are currently splitting the results from LDAP upon a comma, then you
+   should check carefully to see if adjustments are needed.
+
+   This change lets cautious folks distinguish "comma used as separator for
+   joining values" from "comma inside the data".
+

  * accept_8bitmime now defaults on, which is not RFC compliant but is better
    suited to today's Internet.  See http://cr.yp.to/smtp/8bitmime.html for a
    sane rationale.  Those who wish to be strictly RFC compliant, or know that
  * accept_8bitmime now defaults on, which is not RFC compliant but is better
    suited to today's Internet.  See http://cr.yp.to/smtp/8bitmime.html for a
    sane rationale.  Those who wish to be strictly RFC compliant, or know that


@@ -93,7 +142,7 @@ Exim version 4.80
    is instead given to gnutls_priority_init(3), which expects a priority string;
    this behaviour is much closer to the OpenSSL behaviour.  See:
 
    is instead given to gnutls_priority_init(3), which expects a priority string;
    this behaviour is much closer to the OpenSSL behaviour.  See:
 

-     http://www.gnu.org/software/gnutls/manual/html_node/Priority-Strings.html
+     http://www.gnutls.org/manual/html_node/Priority-Strings.html

 
    for fuller documentation of the strings parsed.  The three gnutls_require_*
    options are still parsed by Exim and, for this release, silently ignored.
 
    for fuller documentation of the strings parsed.  The three gnutls_require_*
    options are still parsed by Exim and, for this release, silently ignored.


@@ -111,6 +160,40 @@ Exim version 4.80
    support for SNI and other features more readily.  We regret that it wasn't
    feasible to retain the three dropped options.
 
    support for SNI and other features more readily.  We regret that it wasn't
    feasible to retain the three dropped options.
 

+ * If built with TLS support, then Exim will now validate the value of
+   the main section tls_require_ciphers option at start-up.  Before, this
+   would cause a STARTTLS 4xx failure, now it causes a failure to start.
+   Running with a broken configuration which causes failures that may only
+   be left in the logs has been traded off for something more visible.  This
+   change makes an existing problem more prominent, but we do not believe
+   anyone would deliberately be running with an invalid tls_require_ciphers
+   option.
+
+   This also means that library linkage issues caused by conflicts of some
+   kind might take out the main daemon, not just the delivery or receiving
+   process.  Conceivably some folks might prefer to continue delivering
+   mail plaintext when their binary is broken in this way, if there is a
+   server that is a candidate to receive such mails that does not advertise
+   STARTTLS.  Note that Exim is typically a setuid root binary and given
+   broken linkage problems that cause segfaults, we feel it is safer to
+   fail completely.  (The check is not done as root, to ensure that problems
+   here are not made worse by the check).
+
+ * The "tls_dhparam" option has been updated, so that it can now specify a
+   path or an identifier for a standard DH prime from one of a few RFCs.
+   The default for OpenSSL is no longer to not use DH but instead to use
+   one of these standard primes.  The default for GnuTLS is no longer to use
+   a file in the spool directory, but to use that same standard prime.
+   The option is now used by GnuTLS too.  If it points to a path, then
+   GnuTLS will use that path, instead of a file in the spool directory;
+   GnuTLS will attempt to create it if it does not exist.
+
+   To preserve the previous behaviour of generating files in the spool
+   directory, set "tls_dhparam = historic".  Since prior releases of Exim
+   ignored tls_dhparam when using GnuTLS, this can safely be done before
+   the upgrade.
+
+

 
 Exim version 4.77
 -----------------
 
 Exim version 4.77
 -----------------