.end -> .wen

[exim.git] / src / README.UPDATING

diff --git a/src/README.UPDATING b/src/README.UPDATING
index 81e767efea826ca550b1de7743b1cdc99eb5cfb7..e685b8ec3d4aed6544f8c3067d85fb2c7d6805dc 100644 (file)
--- a/src/README.UPDATING
+++ b/src/README.UPDATING
@@ -26,9 +26,12 @@ 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 4.78
+Exim version 4.80

 -----------------
 
 -----------------
 

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

  * 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
    of values with embedded newlines, which caused spool file corruption.
  * 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
    of values with embedded newlines, which caused spool file corruption.


@@ -63,6 +66,11 @@ Exim version 4.78
    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
  * 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


@@ -77,16 +85,18 @@ Exim version 4.78
    new option, you can safely force it off before upgrading, to decouple
    configuration changes from the binary upgrade while remaining RFC compliant.
 
    new option, you can safely force it off before upgrading, to decouple
    configuration changes from the binary upgrade while remaining RFC compliant.
 

- * The GnuTLS support has been mostly rewritten, to use 2.12.x APIs.  As part
-   of this, these three options are no longer supported:
+ * The GnuTLS support has been mostly rewritten, to use APIs which don't cause
+   deprecation warnings in GnuTLS 2.12.x.  As part of this, these three options
+   are no longer supported:

 
      gnutls_require_kx
      gnutls_require_mac
      gnutls_require_protocols
 
 
      gnutls_require_kx
      gnutls_require_mac
      gnutls_require_protocols
 

-   Their functionality is entirely subsumed into tls_require_ciphers, which is
-   no longer parsed apart by Exim but is instead given to
-   gnutls_priority_init(3), which is no longer an Exim list.  See:
+   Their functionality is entirely subsumed into tls_require_ciphers.  In turn,
+   tls_require_ciphers is no longer an Exim list and is not parsed by Exim, but
+   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.gnu.org/software/gnutls/manual/html_node/Priority-Strings.html
 


@@ -96,11 +106,35 @@ Exim version 4.78
    parsing entirely and the presence of the options will be a configuration
    error.
 
    parsing entirely and the presence of the options will be a configuration
    error.
 

+   Note that by default, GnuTLS will not accept RSA-MD5 signatures in chains.
+   A tls_require_ciphers value of NORMAL:%VERIFY_ALLOW_SIGN_RSA_MD5 may
+   re-enable support, but this is not supported by the Exim maintainers.
+   Our test suite no longer includes MD5-based certificates.
+

    This rewrite means that Exim will continue to build against GnuTLS in the
    future, brings Exim closer to other GnuTLS applications and lets us add
    support for SNI and other features more readily.  We regret that it wasn't
    feasible to retain the three dropped options.
 
    This rewrite means that Exim will continue to build against GnuTLS in the
    future, brings Exim closer to other GnuTLS applications and lets us add
    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).
+

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


@@ -111,6 +145,9 @@ Exim version 4.77
    problem.  Prior to this release, supported values were "TLS1" and "SSL3",
    so you should be able to update configuration prior to update.
 
    problem.  Prior to this release, supported values were "TLS1" and "SSL3",
    so you should be able to update configuration prior to update.
 

+    [nb: gnutls_require_protocols removed in Exim 4.80, instead use
+         tls_require_ciphers to provide a priority string; see notes above]
+

  * The match_<type>{string1}{string2} expansion conditions no longer subject
    string2 to string expansion, unless Exim was built with the new
    "EXPAND_LISTMATCH_RHS" option.  Too many people have inadvertently created
  * The match_<type>{string1}{string2} expansion conditions no longer subject
    string2 to string expansion, unless Exim was built with the new
    "EXPAND_LISTMATCH_RHS" option.  Too many people have inadvertently created