X-Git-Url: https://git.exim.org/exim.git/blobdiff_plain/f4952db2835a261d478321c930db5af27496e598..exim-4_85_RC4:/doc/doc-txt/experimental-spec.txt diff --git a/doc/doc-txt/experimental-spec.txt b/doc/doc-txt/experimental-spec.txt index e7a0d0668..4a2a04bb4 100644 --- a/doc/doc-txt/experimental-spec.txt +++ b/doc/doc-txt/experimental-spec.txt @@ -759,11 +759,12 @@ b. Configure, somewhere before the DATA ACL, the control option to -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 @@ -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 -EXPERIMENTAL_TPDA=yes +EXPERIMENTAL_EVENT=yes 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. -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: - 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. -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 @@ -805,7 +806,7 @@ content is event_dependent: 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: @@ -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 - message_exim_id + message_exim_id, verify_mode 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}}', \ @@ -831,12 +832,12 @@ tpda_event_action = ${if = {msg:delivery}{$tpda_event} \ '${quote_pgsql:$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. -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: @@ -848,8 +849,13 @@ following will be forced: 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 @@ -1138,6 +1144,8 @@ the next hop does not support DSN. Adding it to a redirect router makes no difference. + + Certificate name checking -------------------------------------------------------------- The X509 certificates used for TLS are supposed be verified @@ -1145,16 +1153,33 @@ 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". +included to do so for server certificates, and a new smtp transport option +"tls_verify_cert_hostnames" supported which takes a hostlist +which must match the target host for the additional checks must be made. +The option currently defaults to empty, but this may change in +the future. "*" is probably a suitable value. +Whether certificate verification is done at all, and the result of +it failing, is stll under the control of "tls_verify_hosts" nad +"tls_try_verify_hosts". + +The name being checked is that for the host, generally +the result of an MX lookup. 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). +The equivalent check on the server for client certificates is not +implemented. At least one major email provider is using a client +certificate which fails this check. They do not retry either without +the client certificate or in clear. + +It is possible to duplicate the effect of this checking by +creative use of Events. + + + DANE ------------------------------------------------------------ @@ -1277,12 +1302,13 @@ 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 the TLSA lookup succeeds, a TLS connection will be required -for the host. +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) -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 @@ -1290,6 +1316,10 @@ If dane is in use the following transport options are ignored: 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. @@ -1298,7 +1328,7 @@ 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 -in combination with EXPERIMENTAL_TPDA), and a new variable +in combination with EXPERIMENTAL_EVENT), and a new variable $tls_out_tlsa_usage (detailed above).