-PH/01 The format in which GnuTLS parameters are written to the gnutls-param
- file in the spool directory has been changed. This change has been made
- to alleviate problems that some people had with the generation of the
- parameters by Exim when /dev/random was exhausted. In this situation,
- Exim would hang until /dev/random acquired some more entropy.
-
- The new code exports and imports the DH and RSA parameters in PEM
- format. This means that the parameters can be generated externally using
- the certtool command that is part of GnuTLS.
-
- To replace the parameters with new ones, instead of deleting the file
- and letting Exim re-create it, you can generate new parameters using
- certtool and, when this has been done, replace Exim's cache file by
- renaming. The relevant commands are something like this:
-
- # rm -f new.params
- # touch new.params
- # chown exim:exim new.params
- # chmod 0400 new.params
- # certtool --generate-privkey --bits 512 >new.params
- # echo "" >>new.params
- # certtool --generate-dh-params --bits 1024 >> new.params
- # mv new.params params
-
- If Exim never has to generate the parameters itself, the possibility of
- stalling is removed.
-
-PH/02 A new expansion item for dynamically loading and calling a locally-
- written C function is now provided, if Exim is compiled with
-
- EXPAND_DLFUNC=yes
-
- set in Local/Makefile. The facility is not included by default (a
- suitable error is given if you try to use it when it is not there.)
-
- If you enable EXPAND_DLFUNC, you should also be aware of the new redirect
- router option forbid_filter_dlfunc. If you have unprivileged users on
- your system who are permitted to create filter files, you might want to
- set forbid_filter_dlfunc=true in the appropriate router, to stop them
- using ${dlfunc to run code within Exim.
-
- You load and call an external function like this:
-
- ${dlfunc{/some/file}{function}{arg1}{arg2}...}
-
- Once loaded, Exim remembers the dynamically loaded object so that it
- doesn't reload the same object file in the same Exim process (but of
- course Exim does start new processes frequently).
-
- There may be from zero to eight arguments to the function. When compiling
- a local function that is to be called in this way, local_scan.h should be
- included. The Exim variables and functions that are defined by that API
- are also available for dynamically loaded functions. The function itself
- must have the following type:
-
- int dlfunction(uschar **yield, int argc, uschar *argv[])
-
- Where "uschar" is a typedef for "unsigned char" in local_scan.h. The
- function should return one of the following values:
-
- OK Success. The string that is placed in "yield" is put into
- the expanded string that is being built.
-
- FAIL A non-forced expansion failure occurs, with the error
- message taken from "yield", if it is set.
-
- FAIL_FORCED A forced expansion failure occurs, with the error message
- taken from "yield" if it is set.
-
- ERROR Same as FAIL, except that a panic log entry is written.
-
- When compiling a function that is to be used in this way with gcc,
- you need to add -shared to the gcc command. Also, in the Exim build-time
- configuration, you must add -export-dynamic to EXTRALIBS.
-
-TF/01 $received_time is a new expansion variable containing the time and date
- as a number of seconds since the start of the Unix epoch when the
- current message was received.
-
-PH/03 There is a new value for RADIUS_LIB_TYPE that can be set in
- Local/Makefile. It is RADIUSCLIENTNEW, and it requests that the new API,
- in use from radiusclient 0.4.0 onwards, be used. It does not appear to be
- possible to detect the different versions automatically.
-
-PH/04 There is a new option called acl_not_smtp_mime that allows you to scan
- MIME parts in non-SMTP messages. It operates in exactly the same way as
- acl_smtp_mime
-
-PH/05 It is now possible to redefine a macro within the configuration file.
- The macro must have been previously defined within the configuration (or
- an included file). A definition on the command line using the -D option
- causes all definitions and redefinitions within the file to be ignored.
- In other words, -D overrides any values that are set in the file.
- Redefinition is specified by using '==' instead of '='. For example:
-
- MAC1 = initial value
- ...
- MAC1 == updated value
-
- Redefinition does not alter the order in which the macros are applied to
- the subsequent lines of the configuration file. It is still the same
- order in which the macros were originally defined. All that changes is
- the macro's value. Redefinition makes it possible to accumulate values.
- For example:
-
- MAC1 = initial value
- ...
- MAC1 == MAC1 and something added
-
- This can be helpful in situations where the configuration file is built
- from a number of other files.
-
-PH/06 Macros may now be defined or redefined between router, transport,
- authenticator, or ACL definitions, as well as in the main part of the
- configuration. They may not, however, be changed within an individual
- driver or ACL, or in the local_scan, retry, or rewrite sections of the
- configuration.
-
-PH/07 $acl_verify_message is now set immediately after the failure of a
- verification in an ACL, and so is available in subsequent modifiers. In
- particular, the message can be preserved by coding like this:
-
- warn !verify = sender
- set acl_m0 = $acl_verify_message
-
- Previously, $acl_verify_message was set only while expanding "message"
- and "log_message" when a very denied access.
-
-PH/08 The redirect router has two new options, sieve_useraddress and
- sieve_subaddress. These are passed to a Sieve filter to specify the :user
- and :subaddress parts of an address. Both options are unset by default.
- However, when a Sieve filter is run, if sieve_useraddress is unset, the
- entire original local part (including any prefix or suffix) is used for
- :user. An unset subaddress is treated as an empty subaddress.