UTF8: Cert namechecks always use a-label

[users/heiko/exim.git] / doc / doc-txt / experimental-spec.txt

diff --git a/doc/doc-txt/experimental-spec.txt b/doc/doc-txt/experimental-spec.txt
index 2f44fce26fb7ff7be6788c832265f4842e70c34a..d446f6b67716c19932c4e29cf4f85d6f5f48d231 100644 (file)
--- a/doc/doc-txt/experimental-spec.txt
+++ b/doc/doc-txt/experimental-spec.txt
@@ -623,10 +623,10 @@ exim will send these forensic emails.  It's also advised that you
 configure a dmarc_forensic_sender because the default sender address
 construction might be inadequate.
 
 configure a dmarc_forensic_sender because the default sender address
 construction might be inadequate.
 

-  control = dmarc_forensic_enable
+  control = dmarc_enable_forensic

 
 (AGAIN: You can choose not to send these forensic reports by simply
 
 (AGAIN: You can choose not to send these forensic reports by simply

-not putting the dmarc_forensic_enable control line at any point in
+not putting the dmarc_enable_forensic control line at any point in

 your exim config.  If you don't tell it to send them, it will not
 send them.)
 
 your exim config.  If you don't tell it to send them, it will not
 send them.)
 


@@ -755,15 +755,16 @@ b. Configure, somewhere before the DATA ACL, the control option to
 
   deny    dmarc_status   = reject
           !authenticated = *
 
   deny    dmarc_status   = reject
           !authenticated = *

-          message        = Message from $domain_used_domain failed sender's DMARC policy, REJECT
+          message        = Message from $dmarc_used_domain failed sender's DMARC policy, REJECT

 
 
 
 
 
 

-Transport post-delivery actions
+Event Actions

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

-An arbitrary per-transport string can be expanded upon various transport events
-and (for SMTP transports) a second string on deferrals caused by a host error.
+(Renamed from TPDA, Transport post-delivery actions)
+
+An arbitrary per-transport string can be expanded upon various transport events.

 Additionally a main-section configuration option can be expanded on some
 per-message events.
 This feature may be used, for example, to write exim internal log information
 Additionally a main-section configuration option can be expanded on some
 per-message events.
 This feature may be used, for example, to write exim internal log information


@@ -771,33 +772,33 @@ This feature may be used, for example, to write exim internal log information
 
 In order to use the feature, you must compile with
 
 
 In order to use the feature, you must compile with
 

-EXPERIMENTAL_TPDA=yes
+EXPERIMENTAL_EVENT=yes

 
 in your Local/Makefile
 
 and define one or both of
 
 in your Local/Makefile
 
 and define one or both of

-- the tpda_event_action option in the transport
-- the delivery_event_action
+- the event_action option in the transport
+- the event_action main option

 to be expanded when the event fires.
 
 to be expanded when the event fires.
 

-A new variable, $tpda_event, is set to the event type when the
+A new variable, $event_name, is set to the event type when the

 expansion is done.  The current list of events is:
 
 expansion is done.  The current list of events is:
 

-       msg:complete            main            per message
-       msg:delivery            transport       per recipient
-       msg:host:defer          transport       per attempt
-       msg:fail:delivery       main            per recipient
-       msg:fail:internal       main            per recipient
-       tcp:connect             transport       per connection
-       tcp:close               transport       per connection
-       tls:cert                transport       per certificate in verification chain
-       smtp:connect            transport       per connection
-
-The expansion is called for all event types, and should use the $tpda_event
+ msg:complete          after  main       per message
+ msg:delivery          after  transport  per recipient
+ msg:host:defer                after  transport  per attempt
+ msg:fail:delivery     after  main       per recipient
+ msg:fail:internal     after  main       per recipient
+ tcp:connect           before transport  per connection
+ tcp:close             after  transport  per connection
+ tls:cert              before both       per certificate in verification chain
+ smtp:connect          after  transport  per connection
+
+The expansion is called for all event types, and should use the $event_name

 value to decide when to act.  The variable data is a colon-separated
 list, describing an event tree.
 
 value to decide when to act.  The variable data is a colon-separated
 list, describing an event tree.
 

-There is an auxilary variable, $tpda_data, for which the
+There is an auxilary variable, $event_data, for which the

 content is event_dependent:
 
        msg:delivery            smtp confirmation mssage
 content is event_dependent:
 
        msg:delivery            smtp confirmation mssage


@@ -805,7 +806,7 @@ content is event_dependent:
        tls:cert                verification chain depth
        smtp:connect            smtp banner
 
        tls:cert                verification chain depth
        smtp:connect            smtp banner
 

-The msg:host:defer event populates one extra variable, $tpda_defer_errno.
+The msg:host:defer event populates one extra variable, $event_defer_errno.

 
 The following variables are likely to be useful depending on the event type:
 
 
 The following variables are likely to be useful depending on the event type:
 


@@ -815,12 +816,12 @@ The following variables are likely to be useful depending on the event type:
        tls_out_peercert
        lookup_dnssec_authenticated, tls_out_dane
        sending_ip_address, sending_port
        tls_out_peercert
        lookup_dnssec_authenticated, tls_out_dane
        sending_ip_address, sending_port

-       message_exim_id
+       message_exim_id, verify_mode

 
 
 An example might look like:
 
 
 
 An example might look like:
 

-tpda_event_action = ${if = {msg:delivery}{$tpda_event} \
+event_action = ${if eq {msg:delivery}{$event_name} \

 {${lookup pgsql {SELECT * FROM record_Delivery( \
     '${quote_pgsql:$sender_address_domain}',\
     '${quote_pgsql:${lc:$sender_address_local_part}}', \
 {${lookup pgsql {SELECT * FROM record_Delivery( \
     '${quote_pgsql:$sender_address_domain}',\
     '${quote_pgsql:${lc:$sender_address_local_part}}', \


@@ -831,12 +832,12 @@ tpda_event_action = ${if = {msg:delivery}{$tpda_event} \
     '${quote_pgsql:$message_exim_id}')}} \
 } {}}
 
     '${quote_pgsql:$message_exim_id}')}} \
 } {}}
 

-The string is expanded for each of the supported events and any
-side-effects will happen.  The result is then discarded.
+The string is expanded when each of the supported events occur
+and any side-effects of the expansion will happen.

 Note that for complex operations an ACL expansion can be used.
 
 
 Note that for complex operations an ACL expansion can be used.
 
 

-The expansion of the tpda_event_action option should normally
+The expansion of the event_action option should normally

 return an empty string.  Should it return anything else the
 following will be forced:
 
 return an empty string.  Should it return anything else the
 following will be forced:
 


@@ -848,8 +849,13 @@ following will be forced:
        tls:cert        refuse verification
        smtp:connect    close connection
 
        tls:cert        refuse verification
        smtp:connect    close connection
 

+No other use is made of the result string.

 
 
 
 

+Known issues:
+- the tls:cert event is only called for the cert chain elements
+  received over the wire, with GnuTLS.  OpenSSL gives the entire
+  chain including thse loaded locally.

 
 
 Redis Lookup
 
 
 Redis Lookup


@@ -1078,82 +1084,39 @@ QUIT
 221 mail.example.net closing connection
 
 
 221 mail.example.net closing connection
 
 

-DSN Support
---------------------------------------------------------------
-
-DSN Support tries to add RFC 3461 support to Exim. It adds support for
-*) the additional parameters for MAIL FROM and RCPT TO
-*) RFC complient MIME DSN messages for all of
-   success, failure and delay notifications
-*) dsn_advertise_hosts main option to select which hosts are able
-   to use the extension
-*) dsn_lasthop router switch to end DSN processing
-
-In case of failure reports this means that the last three parts, the message body
-intro, size info and final text, of the defined template are ignored since there is no
-logical place to put them in the MIME message.
-
-All the other changes are made without changing any defaults
-
-Building exim:
---------------
-
-Define
-EXPERIMENTAL_DSN=YES
-in your Local/Makefile.
-
-Configuration:
---------------
-All DSNs are sent in MIME format if you built exim with EXPERIMENTAL_DSN=YES
-No option needed to activate it, and no way to turn it off.
-
-Failure and delay DSNs are triggered as usual except a sender used NOTIFY=...
-to prevent them.

 
 

-Support for Success DSNs is added and activated by NOTIFY=SUCCESS by clients.

 
 

-Add
-dsn_advertise_hosts = *
-or a more restrictive host_list to announce DSN in EHLO answers
-
-Those hosts can then use NOTIFY,ENVID,RET,ORCPT options.
-
-If a message is relayed to a DSN aware host without changing the envelope
-recipient the options are passed along and no success DSN is generated.
-
-A redirect router will always trigger a success DSN if requested and the DSN
-options are not passed any further.
+SOCKS
+------------------------------------------------------------
+Support for proxying outbound SMTP via a Socks 5 proxy
+(RFC 1928) is included if Exim is compiled with
+EXPERIMENTAL_SOCKS defined.

 
 

-A success DSN always contains the recipient address as submitted by the
-client as required by RFC. Rewritten addresses are never exposed.
+If an smtp transport has a nonempty socks_proxy option
+defined, this is active.  The option is expanded and
+should be a list (colon-separated by default) of
+proxy specifiers.  Each proxy specifier is a list
+(space-separated by default) where the initial element
+is an IP address and any subsequent elements are options.

 
 

-If you used DSN patch up to 1.3 before remove all "dsn_process" switches from
-your routers since you don't need them anymore. There is no way to "gag"
-success DSNs anymore. Announcing DSN means answering as requested.
+Options are a string <name>=<value>.
+These options are currently defined:
+- "auth", with possible values "none" and "name".
+  Using "name" selects username/password authentication
+  per RFC 1929. Default is "none".
+- "name" sets the authentication username. Default is empty.
+- "pass" sets the authentication password. Default is empty.
+- "port" sets the tcp port number for the proxy. Default is 1080.
+- "tmo" sets a connection timeout in seconds for this proxy. Default is 5.

 
 

-You can prevent Exim from passing DSN options along to other DSN aware hosts by defining
-dsn_lasthop
-in a router. Exim will then send the success DSN himself if requested as if
-the next hop does not support DSN.
-Adding it to a redirect router makes no difference.
+Proxies from the list are tried in order until
+one responds.  The timeout for the overall connection
+applies to the set of proxied attempts.

 
 

+If events are used, the remote IP/port during a
+tcp:connect event will be that of the proxy.

 
 

-Certificate name checking
---------------------------------------------------------------
-The X509 certificates used for TLS are supposed be verified
-that they are owned by the expected host.  The coding of TLS
-support to date has not made these checks.

 
 

-If built with EXPERIMENTAL_CERTNAMES defined, code is
-included to do so, and a new smtp transport option
-"tls_verify_cert_hostname" supported which takes a list of
-names for which the checks must be made.  The host must
-also be in "tls_verify_hosts".
-
-Both Subject and Subject-Alternate-Name certificate fields
-are supported, as are wildcard certificates (limited to
-a single wildcard being the initial component of a 3-or-more
-component FQDN).

 
 
 DANE
 
 
 DANE


@@ -1178,6 +1141,10 @@ admins of the target server.   The attack surface presented
 by (a) is thought to be smaller than that of the set
 of root CAs.
 
 by (a) is thought to be smaller than that of the set
 of root CAs.
 

+It also allows the server to declare (implicitly) that
+connections to it should use TLS.  An MITM could simply
+fail to pass on a server's STARTTLS.
+

 DANE scales better than having to maintain (and
 side-channel communicate) copies of server certificates
 for every possible target server.  It also scales
 DANE scales better than having to maintain (and
 side-channel communicate) copies of server certificates
 for every possible target server.  It also scales


@@ -1202,12 +1169,12 @@ There are no changes to Exim specific to server-side
 operation of DANE.
 
 The TLSA record for the server may have "certificate
 operation of DANE.
 
 The TLSA record for the server may have "certificate

-usage" of DANE_TA(2) or DANE_EE(3).  The latter specifies
+usage" of DANE-TA(2) or DANE-EE(3).  The latter specifies

 the End Entity directly, i.e. the certificate involved
 is that of the server (and should be the sole one transmitted
 during the TLS handshake); this is appropriate for a
 single system, using a self-signed certificate.
 the End Entity directly, i.e. the certificate involved
 is that of the server (and should be the sole one transmitted
 during the TLS handshake); this is appropriate for a
 single system, using a self-signed certificate.

-  DANE_TA usage is effectively declaring a specific CA
+  DANE-TA usage is effectively declaring a specific CA

 to be used; this might be a private CA or a public,
 well-known one.  A private CA at simplest is just
 a self-signed certificate which is used to sign
 to be used; this might be a private CA or a public,
 well-known one.  A private CA at simplest is just
 a self-signed certificate which is used to sign


@@ -1219,7 +1186,7 @@ the entire certificate chain from CA to server-certificate.
 If a public CA is used then all clients must be primed with it
 (losing one advantage of DANE) - but the attack surface is
 reduced from all public CAs to that single CA.
 If a public CA is used then all clients must be primed with it
 (losing one advantage of DANE) - but the attack surface is
 reduced from all public CAs to that single CA.

-DANE_TA is commonly used for several services and/or
+DANE-TA is commonly used for several services and/or

 servers, each having a TLSA query-domain CNAME record,
 all of which point to a single TLSA record.
 
 servers, each having a TLSA query-domain CNAME record,
 all of which point to a single TLSA record.
 


@@ -1236,13 +1203,13 @@ is useful for quickly generating TLSA records; and commands like
 
 are workable for 4th-field hashes.
 
 
 are workable for 4th-field hashes.
 

-For use with the DANE_TA model, server certificates
+For use with the DANE-TA model, server certificates

 must have a correct name (SubjectName or SubjectAltName).
 
 The use of OCSP-stapling should be considered, allowing
 for fast revocation of certificates (which would otherwise
 be limited by the DNS TTL on the TLSA records).  However,
 must have a correct name (SubjectName or SubjectAltName).
 
 The use of OCSP-stapling should be considered, allowing
 for fast revocation of certificates (which would otherwise
 be limited by the DNS TTL on the TLSA records).  However,

-this is likely to only be usable with DANE_TA.  NOTE: the
+this is likely to only be usable with DANE-TA.  NOTE: the

 default of requesting OCSP for all hosts is modified iff
 DANE is in use, to:
 
 default of requesting OCSP for all hosts is modified iff
 DANE is in use, to:
 


@@ -1253,10 +1220,10 @@ DANE is in use, to:
 The (new) variable $tls_out_tlsa_usage is a bitfield with
 numbered bits set for TLSA record usage codes.
 The zero above means DANE was not in use,
 The (new) variable $tls_out_tlsa_usage is a bitfield with
 numbered bits set for TLSA record usage codes.
 The zero above means DANE was not in use,

-the four means that only DANE_TA usage TLSA records were
-found. If the definition of hosts_require_ocsp or
-hosts_request_ocsp includes the string "tls_out_tlsa_usage",
-they are re-expanded in time to control the OCSP request.
+the four means that only DANE-TA usage TLSA records were
+found. If the definition of hosts_request_ocsp includes the
+string "tls_out_tlsa_usage", they are re-expanded in time to
+control the OCSP request.

 
 This modification of hosts_request_ocsp is only done if
 it has the default value of "*".  Admins who change it, and
 
 This modification of hosts_request_ocsp is only done if
 it has the default value of "*".  Admins who change it, and


@@ -1271,15 +1238,26 @@ hosts_try_dane and hosts_require_dane.  They do the obvious thing.
 DANE will only be usable if the target host has DNSSEC-secured
 MX, A and TLSA records.
 
 DANE will only be usable if the target host has DNSSEC-secured
 MX, A and TLSA records.
 

+A TLSA lookup will be done if either of the above options match
+and the host-lookup succeded using dnssec.
+If a TLSA lookup is done and succeeds, a DANE-verified TLS connection
+will be required for the host.
+

 (TODO: specify when fallback happens vs. when the host is not used)
 
 (TODO: specify when fallback happens vs. when the host is not used)
 

-If dane is in use the following transport options are ignored:
+If DANE is requested and useable (see above) the following transport
+options are ignored:
+  hosts_require_tls

   tls_verify_hosts
   tls_try_verify_hosts
   tls_verify_certificates
   tls_crl
   tls_verify_cert_hostnames
 
   tls_verify_hosts
   tls_try_verify_hosts
   tls_verify_certificates
   tls_crl
   tls_verify_cert_hostnames
 

+If DANE is not usable, whether requested or not, and CA-anchored
+verification evaluation is wanted, the above variables should be set
+appropriately.
+

 Currently dnssec_request_domains must be active (need to think about that)
 and dnssec_require_domains is ignored.
 
 Currently dnssec_request_domains must be active (need to think about that)
 and dnssec_require_domains is ignored.
 


@@ -1288,10 +1266,77 @@ in the delivery log line will show as "CV=dane".
 
 There is a new variable $tls_out_dane which will have "yes" if
 verification succeeded using DANE and "no" otherwise (only useful
 
 There is a new variable $tls_out_dane which will have "yes" if
 verification succeeded using DANE and "no" otherwise (only useful

-in combination with EXPERIMENTAL_TPDA), and a new variable
+in combination with EXPERIMENTAL_EVENT), and a new variable

 $tls_out_tlsa_usage (detailed above).
 
 
 $tls_out_tlsa_usage (detailed above).
 
 

+
+SMTPUTF8
+------------------------------------------------------------
+Internationalised mail name handling.
+RFCs 6530, 6533, 5890
+
+Compile with EXPERIMENTAL_INTERNATIONAL and libidn.
+
+New main config option smtputf8_advertise_hosts, default '*',
+a host list.  If this matches the sending host and
+accept_8bitmime is true (the default) then the ESMTP option
+SMTPUTF8 will be advertised.
+
+If the sender specifies the SMTPUTF8 option on a MAIL command
+international handling for the message is enabled and
+the expansion variable $message_smtputf8 will have value TRUE.
+
+The option allow_utf8_domains is set to true for this
+message. All DNS lookups are converted to a-label form
+whatever the setting of allow_utf8_domains.
+
+Both localparts and domain are maintained as the original
+utf8 form internally; any matching or regex use will
+require appropriate care.  Filenames created, eg. by
+the appendfile transport, will have utf8 name.
+
+Helo names sent by the smtp transport will have any utf8
+components expanded to a-label form.
+
+Any certificate name checks will be done using the a-label
+form of the name.
+
+Log lines and Received-by: header lines will aquire a "utf8"
+prefix on the protocol element, eg. utf8esmtp.
+
+New expansion operators:
+       ${utf8_domain_to_alabel:str}
+       ${utf8_domain_from_alabel:str}
+       ${utf8_localpart_to_alabel:str}
+       ${utf8_localpart_from_alabel:str}
+
+New "control = utf8_downconvert" ACL modifier,
+sets a flag requiring that addresses are converted to
+a-label form before smtp delivery, for use in a
+Message Submission Agent context.  Can also be
+phrased as "control = utf8_downconvert/1" and is
+mandatory.  The flag defaults to zero and can be cleared
+by "control = utf8_downconvert/0".  The value "-1"
+may also be used, to use a-label for only if the
+destination host does not support SMTPUTF8.
+
+If mua_wrapper is set, the utf8_downconvert control
+defaults to -1 (convert if needed).
+
+
+There is no explicit support for VRFY and EXPN.
+Configurations supporting these should inspect
+$smtp_command_argument for an SMTPUTF8 argument.
+
+There is no support for LMTP on Unix sockets.
+Using the "lmtp" protocol option on an smtp transport,
+for LMTP over TCP, should work as expected.
+
+Known issues:
+ - DSN unitext handling is not present
+ - no provision for converting logging from or to UTF-8
+

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