From: Jeremy Harris <jgh146exb@wizmail.org>
Date: Thu, 29 Dec 2016 15:55:45 +0000 (+0000)
Subject: I18N: avoid trying to downconvert all-ascii domain names.
X-Git-Tag: exim-4_89_RC1~56
X-Git-Url: https://git.exim.org/users/jgh/exim.git/commitdiff_plain/496e0df604efcc9b4d3c8878c7563f01cb0f44ea

I18N: avoid trying to downconvert all-ascii domain names.

With the IDNA-2008 handling downconversion results in lowercasing;
so avoid doing that if possible.
---

diff --git a/src/src/utf8.c b/src/src/utf8.c
index be5bcb078..e8690fc39 100644
--- a/src/src/utf8.c
+++ b/src/src/utf8.c
@@ -52,6 +52,10 @@ uschar * s1, * s;
 int rc;
 
 #ifdef SUPPORT_I18N_2008
+/* Avoid lowercasing plain-ascii domains */
+if (!string_is_utf8(utf8))
+  return string_copy(utf8);
+
 /* Only lowercase is accepted by the library call.  A pity since we lose
 any mixed-case annotation.  This does not really matter for a domain. */
   {