Refactor common uses of list-checking

[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 2d34de0f76d2e9a7c5c3f29e30ee90c2e8143070..d57cbf9038a1373755c692ef33f4c40879f6b3f8 100644 (file)
--- a/doc/doc-txt/experimental-spec.txt
+++ b/doc/doc-txt/experimental-spec.txt
@@ -791,7 +791,7 @@ expansion is done.  The current list of events is:
  msg:fail:internal     after  main       per recipient
  tcp:connect           before transport  per connection
  tcp:close             after  transport  per connection
- tls:cert              before transport  per certificate in verification chain
+ 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
@@ -816,7 +816,7 @@ 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:
@@ -852,6 +852,10 @@ following will be forced:
 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
@@ -1140,6 +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
@@ -1147,16 +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
 ------------------------------------------------------------
@@ -1300,7 +1323,7 @@ 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).