From 3a06d0148235262301a342c4af37f024820b126f Mon Sep 17 00:00:00 2001
From: "Heiko Schlittermann (HS12-RIPE)" <hs@schlittermann.de>
Date: Sat, 3 Apr 2021 09:29:13 +0200
Subject: [PATCH] update doc

---
 doc/doc-docbook/spec.xfpt | 29 +++++++++++++++++++++++++++++
 doc/doc-txt/NewStuff      |  3 +++
 2 files changed, 32 insertions(+)

diff --git a/doc/doc-docbook/spec.xfpt b/doc/doc-docbook/spec.xfpt
index a76103688..5d368654a 100644
--- a/doc/doc-docbook/spec.xfpt
+++ b/doc/doc-docbook/spec.xfpt
@@ -237,6 +237,14 @@
   <secondary>failure report</secondary>
   <see><emphasis>bounce message</emphasis></see>
 </indexterm>
+<indexterm role="concept">
+  <primary>de-tainting</primary>
+  <see><emphasis>tainting, de-tainting</emphasis></see>
+</indexterm>
+<indexterm role="concept">
+  <primary>detainting</primary>
+  <see><emphasis>tainting, de-tainting</emphasis></see>
+</indexterm>
 <indexterm role="concept">
   <primary>dialup</primary>
   <see><emphasis>intermittently connected hosts</emphasis></see>
@@ -9578,6 +9586,8 @@ reasons,
 and expansion of data deriving from the sender (&"tainted data"&)
 .new
 is not permitted (including acessing a file using a tainted name).
+The main config option &%allow_insecure_tainted_data%& can be used as
+mitigation during uprades to more secure configurations.
 .wen
 
 .new
@@ -14557,6 +14567,7 @@ listed in more than one group.
 .section "Miscellaneous" "SECID96"
 .table2
 .row &%add_environment%&             "environment variables"
+.row &%allow_insecure_tainted_data%& "turn taint errors into warnings"
 .row &%bi_command%&                  "to run for &%-bi%& command line option"
 .row &%debug_store%&                 "do extra internal checks"
 .row &%disable_ipv6%&                "do no IPv6 processing"
@@ -15167,6 +15178,18 @@ domains (defined in the named domain list &%local_domains%& in the default
 configuration). This &"magic string"& matches the domain literal form of all
 the local host's IP addresses.
 
+.new
+.option allow_insecure_tainted_data main boolean false
+.cindex "de-tainting"
+.oindex "allow_insecure_tainted_data"
+The handling of tainted data may break older (pre 4.94) configurations.
+Setting this option to "true" turns taint errors (which result in a temporary
+message rejection) into warnings. This option is meant as mitigation only
+and deprecated already today. Future releases of Exim may ignore it.
+The &%taint%& log selector can be used to suppress even the warnings.
+.wen
+
+
 
 .option allow_mx_to_ip main boolean false
 .cindex "MX record" "pointing to IP address"
@@ -38646,6 +38669,7 @@ selection marked by asterisks:
 &` smtp_protocol_error        `&  SMTP protocol errors
 &` smtp_syntax_error          `&  SMTP syntax errors
 &` subject                    `&  contents of &'Subject:'& on <= lines
+&`*taint                      `&  taint errors or warnings
 &`*tls_certificate_verified   `&  certificate verification status
 &`*tls_cipher                 `&  TLS cipher suite on <= and => lines
 &` tls_peerdn                 `&  TLS peer DN on <= and => lines
@@ -39044,6 +39068,11 @@ using a CA trust anchor,
 &`CV=dane`& if using a DNS trust anchor,
 and &`CV=no`& if not.
 .next
+.cindex "log" "Taint warnings"
+&%taint%&: Log warnings about tainted data. This selector can't be
+turned of if &%allow_insecure_tainted_data%& is false (which is the
+default).
+.next
 .cindex "log" "TLS cipher"
 .cindex "TLS" "logging cipher"
 &%tls_cipher%&: When a message is sent or received over an encrypted
diff --git a/doc/doc-txt/NewStuff b/doc/doc-txt/NewStuff
index 50f7b4357..0edba6664 100644
--- a/doc/doc-txt/NewStuff
+++ b/doc/doc-txt/NewStuff
@@ -48,6 +48,9 @@ Version 4.95
 
 13. Option "smtp_accept_msx_per_connection" is now expanded.
 
+13. A main config option "allow_insecure_tainted_data" allows to turn
+    taint errors into warnings.
+
 Version 4.94
 ------------
 
-- 
2.30.2