Fix DKIM information leakage

[users/jgh/exim.git] / doc / doc-docbook / spec.xfpt

diff --git a/doc/doc-docbook/spec.xfpt b/doc/doc-docbook/spec.xfpt
index 9cb1e4972efdf60f9275346051986a0a2996c5f5..5324be398358c333fe7506e5ba1cb80d634ce856 100644 (file)
--- a/doc/doc-docbook/spec.xfpt
+++ b/doc/doc-docbook/spec.xfpt
@@ -5043,11 +5043,17 @@ They can be used to conditionally include parts of a configuration
 
 The following classes of macros are defined:
 .display
-&` _HAVE_                     `&  build-time defines
-&` _DRVR_AUTH_                `&  authenticator drivers
-&` _DRVR_RTR_                 `&  router drivers
-&` _DRVR_TPT_                 `&  transport drivers
-&` _OPT_                      `&  configuration option support
+&` _HAVE_*                    `&  build-time defines
+&` _DRIVER_ROUTER_*           `&  router drivers
+&` _DRIVER_TRANSPORT_*        `&  transport drivers
+&` _DRIVER_AUTHENTICATOR_*    `&  authenticator drivers
+&` _OPT_MAIN_*                `&  main config options
+&` _OPT_ROUTERS_*             `&  generic router options
+&` _OPT_TRANSPORTS_*          `&  generic transport options
+&` _OPT_AUTHENTICATORS_*      `&  generic authenticator options
+&` _OPT_ROUTER_*_*            `&  private router options
+&` _OPT_TRANSPORT_*_*         `&  private transport options
+&` _OPT_AUTHENTICATOR_*_*     `&  private authenticator options
 .endd
 
 Use an &"exim -bP macros"& command to get the list of macros.
@@ -17139,17 +17145,19 @@ prior to the 4.80 release, as Debian used to patch Exim to raise the minimum
 acceptable bound from 1024 to 2048.
 
 
-.option tls_eccurve main string&!! prime256v1
+.option tls_eccurve main string&!! &`auto`&
 .cindex TLS "EC cryptography"
-If built with a recent-enough version of OpenSSL,
-this option selects a EC curve for use by Exim.
+This option selects a EC curve for use by Exim.
 
-Curve names of the form &'prime256v1'& are accepted.
-For even more-recent library versions, names of the form &'P-512'&
-are also accepted, plus the special value &'auto'&
-which tells the library to choose.
+After expansion it must contain a valid EC curve parameter, such as
+&`prime256v1`&, &`secp384r1`&, or &`P-512`&. Consult your OpenSSL manual
+for valid selections.
 
-If the option is set to an empty string, no EC curves will be enabled.
+For OpenSSL versions before (and not including) 1.0.2, the string
+&`auto`& selects &`prime256v1`&. For more recent OpenSSL versions
+&`auto`& tells the library to choose.
+
+If the option expands to an empty string, no EC curves will be enabled.
 
 
 .option tls_ocsp_file main string&!! unset
@@ -26804,7 +26812,7 @@ tls:
 .endd
 This accepts a client certificate that is verifiable against any
 of your configured trust-anchors
-which usually means the full set of public CAs)
+(which usually means the full set of public CAs)
 and which has a SAN with a good account name.
 Note that the client cert is on the wire in-clear, including the SAN,
 whereas a plaintext SMTP AUTH done inside TLS is not.
@@ -31668,6 +31676,15 @@ configuration as follows (example):
 .code
 spamd_address = 192.168.99.45 387
 .endd
+The SpamAssassin protocol relies on a TCP half-close from the client.
+If your SpamAssassin client side is running a Linux system with an
+iptables firewall, consider setting
+&%net.netfilter.nf_conntrack_tcp_timeout_close_wait%& to at least the
+timeout, Exim uses when waiting for a response from the SpamAssassin
+server (currently defaulting to 120s).  With a lower value the Linux
+connection tracking may consider your half-closed connection as dead too
+soon.
+
 
 To use Rspamd (which by default listens on all local addresses
 on TCP port 11333)
@@ -38256,6 +38273,7 @@ These options take (expandable) strings as arguments.
 MANDATORY:
 The domain you want to sign with. The result of this expanded
 option is put into the &%$dkim_domain%& expansion variable.
+If it is empty after expansion, DKIM signing is not done.
 
 .option dkim_selector smtp string&!! unset
 MANDATORY:
@@ -38779,7 +38797,7 @@ must be representable in UTF-16.
 .cindex events
 
 The events mechanism in Exim can be used to intercept processing at a number
-of points.  It was originally invented to giave a way to do customised logging
+of points.  It was originally invented to give a way to do customised logging
 actions (for example, to a database) but can also be used to modify some
 processing actions.
 
@@ -38849,7 +38867,7 @@ with the event type:
 The :defer events populate one extra variable: &$event_defer_errno$&.
 
 For complex operations an ACL expansion can be used in &%event_action%&
-however due to the multiple contextx that Exim operates in during
+however due to the multiple contexts that Exim operates in during
 the course of its processing:
 .ilist
 variables set in transport events will not be visible outside that