From ed26f0f0eb4242706d2012e4abe0152071bb305b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Petr=20Men=C5=A1=C3=ADk?= <pemensik@redhat.com>
Date: Tue, 25 Sep 2018 18:08:46 +0200
Subject: [PATCH] Disable IDN from environment as documented

Manual page of host contained instructions to disable IDN processing
when it was built with libidn2. When refactoring IDN support however,
support for disabling IDN in host and nslookup was lost. Use also
environment variable and document it for nslookup, host and dig.

Support variable CHARSET=ASCII to disable IDN, supported in downstream
RH patch since RHEL 5.
---
 bin/dig/dig.docbook      |  4 +++-
 bin/dig/dighost.c        |  9 +++++++--
 bin/dig/host.docbook     |  2 +-
 bin/dig/nslookup.docbook | 15 +++++++++++++++
 4 files changed, 26 insertions(+), 4 deletions(-)

diff --git a/bin/dig/dig.docbook b/bin/dig/dig.docbook
index bd7510e..5cc696f 100644
--- a/bin/dig/dig.docbook
+++ b/bin/dig/dig.docbook
@@ -1288,7 +1288,9 @@ dig +qr www.isc.org any -x 127.0.0.1 isc.org ns +noqr
       reply from the server.
       If you'd like to turn off the IDN support for some reason, use
       parameters <parameter>+noidnin</parameter> and
-      <parameter>+noidnout</parameter>.
+      <parameter>+noidnout</parameter> or define
+      the <envar>IDN_DISABLE</envar> environment variable.
+
     </para>
   </refsection>
 
diff --git a/bin/dig/dighost.c b/bin/dig/dighost.c
index 341ed80..bb8702c 100644
--- a/bin/dig/dighost.c
+++ b/bin/dig/dighost.c
@@ -825,12 +825,17 @@ make_empty_lookup(void) {
 	looknew->seenbadcookie = false;
 	looknew->badcookie = true;
 #ifdef WITH_IDN_SUPPORT
-	looknew->idnin = true;
+	looknew->idnin = (getenv("IDN_DISABLE") == NULL);
+	if (looknew->idnin) {
+		const char *charset = getenv("CHARSET");
+		if (charset && !strcmp(charset, "ASCII"))
+			looknew->idnin = false;
+	}
 #else
 	looknew->idnin = false;
 #endif
 #ifdef WITH_IDN_OUT_SUPPORT
-	looknew->idnout = true;
+	looknew->idnout = looknew->idnin;
 #else
 	looknew->idnout = false;
 #endif
diff --git a/bin/dig/host.docbook b/bin/dig/host.docbook
index 9c3aeaa..42cbbf9 100644
--- a/bin/dig/host.docbook
+++ b/bin/dig/host.docbook
@@ -378,7 +378,7 @@
       <command>host</command> appropriately converts character encoding of
       domain name before sending a request to DNS server or displaying a
       reply from the server.
-      If you'd like to turn off the IDN support for some reason, defines
+      If you'd like to turn off the IDN support for some reason, define
       the <envar>IDN_DISABLE</envar> environment variable.
       The IDN support is disabled if the variable is set when
       <command>host</command> runs.
diff --git a/bin/dig/nslookup.docbook b/bin/dig/nslookup.docbook
index 3aff4e9..86a09c6 100644
--- a/bin/dig/nslookup.docbook
+++ b/bin/dig/nslookup.docbook
@@ -478,6 +478,21 @@ nslookup -query=hinfo  -timeout=10
     </para>
   </refsection>
 
+  <refsection><info><title>IDN SUPPORT</title></info>
+
+    <para>
+      If <command>nslookup</command> has been built with IDN (internationalized
+      domain name) support, it can accept and display non-ASCII domain names.
+      <command>nslookup</command> appropriately converts character encoding of
+      domain name before sending a request to DNS server or displaying a
+      reply from the server.
+      If you'd like to turn off the IDN support for some reason, define
+      the <envar>IDN_DISABLE</envar> environment variable.
+      The IDN support is disabled if the variable is set when
+      <command>nslookup</command> runs.
+    </para>
+  </refsection>
+
   <refsection><info><title>FILES</title></info>
 
     <para><filename>/etc/resolv.conf</filename>
-- 
2.14.4