From 2aa6c1735a84f6df11b5f5863a704034b820c925 Mon Sep 17 00:00:00 2001
From: Steve Holme <steve_holme@hotmail.com>
Date: Sat, 8 Feb 2020 00:37:03 +0000
Subject: smtp: Support UTF-8 based host names in the VRFY command

---
 lib/smtp.c              | 34 ++++++++++++++++++++++++++++------
 tests/data/Makefile.inc |  2 +-
 tests/data/test961      |  3 +++
 tests/data/test964      | 48 ++++++++++++++++++++++++++++++++++++++++++++++++
 tests/ftpserver.pl      |  8 +++++++-
 5 files changed, 87 insertions(+), 8 deletions(-)
 create mode 100644 tests/data/test964

diff --git a/lib/smtp.c b/lib/smtp.c
index 1718cc2db..3c3dfcbd9 100644
--- a/lib/smtp.c
+++ b/lib/smtp.c
@@ -485,13 +485,35 @@ static CURLcode smtp_perform_command(struct connectdata *conn)
   struct Curl_easy *data = conn->data;
   struct SMTP *smtp = data->req.protop;
 
-  /* Send the command */
-  if(smtp->rcpt)
-    result = Curl_pp_sendf(&conn->proto.smtpc.pp, "%s %s",
-                           smtp->custom && smtp->custom[0] != '\0' ?
-                           smtp->custom : "VRFY",
-                           smtp->rcpt->data);
+  if(smtp->rcpt) {
+    if((!smtp->custom) || (!smtp->custom[0])) {
+      char *address = NULL;
+      struct hostname host = { NULL, NULL, NULL, NULL };
+
+      /* Parse the mailbox to verify into the local address and host name
+         parts, converting the host name to an IDN A-label if necessary */
+      result = smtp_parse_address(conn, smtp->rcpt->data,
+                                  &address, &host);
+      if(result)
+        return result;
+
+      /* Send the VRFY command (Note: The host name part may be absent when the
+         host is a local system) */
+      result = Curl_pp_sendf(&conn->proto.smtpc.pp, "VRFY %s%s%s",
+                             address,
+                             host.name ? "@" : "",
+                             host.name ? host.name : "");
+
+      Curl_free_idnconverted_hostname(&host);
+      free(address);
+    }
+    else
+      /* Send the custom recipient based command such as the EXPN command */
+      result = Curl_pp_sendf(&conn->proto.smtpc.pp, "%s %s", smtp->custom,
+                             smtp->rcpt->data);
+  }
   else
+    /* Send the non-recipient based command such as HELP */
     result = Curl_pp_sendf(&conn->proto.smtpc.pp, "%s",
                            smtp->custom && smtp->custom[0] != '\0' ?
                            smtp->custom : "HELP");
diff --git a/tests/data/Makefile.inc b/tests/data/Makefile.inc
index 8d2ef14ce..5215f442f 100644
--- a/tests/data/Makefile.inc
+++ b/tests/data/Makefile.inc
@@ -109,7 +109,7 @@ test927 test928 test929 test930 test931 test932 test933 test934 test935 \
 test936 test937 test938 test939 test940 test941 test942 test943 test944 \
 test945 test946 test947 test948 test949 test950 test951 test952 test953 \
 test954 test955 test956 test957 test958 test959 test960 test961 test962 \
-test963 \
+test963 test964 \
 \
 test1000 test1001 test1002 test1003 test1004 test1005 test1006 test1007 \
 test1008 test1009 test1010 test1011 test1012 test1013 test1014 test1015 \
diff --git a/tests/data/test961 b/tests/data/test961
index 80ebca887..2e70cb404 100644
--- a/tests/data/test961
+++ b/tests/data/test961
@@ -17,6 +17,9 @@ VRFY
 <server>
 smtp
 </server>
+<features>
+!idn
+</features>
 <setenv>
 LC_ALL=en_US.UTF-8
 LC_CTYPE=en_US.UTF-8
diff --git a/tests/data/test964 b/tests/data/test964
new file mode 100644
index 000000000..326cdd21e
--- /dev/null
+++ b/tests/data/test964
@@ -0,0 +1,48 @@
+<testcase>
+<info>
+<keywords>
+SMTP
+VRFY
+IDN
+</keywords>
+</info>
+
+#
+# Server-side
+<reply>
+</reply>
+
+#
+# Client-side
+<client>
+<server>
+smtp
+</server>
+<features>
+idn
+</features>
+<setenv>
+LC_ALL=en_US.UTF-8
+LC_CTYPE=en_US.UTF-8
+</setenv>
+<precheck>
+perl -MI18N::Langinfo=langinfo,CODESET -e 'die "Needs a UTF-8 locale" if (lc(langinfo(CODESET())) ne "utf-8");'
+</precheck>
+ <name>
+SMTP external VRFY without SMTPUTF8 support (IDN Enabled) - UTF-8 based recipient (host part only)
+ </name>
+<command>
+smtp://%HOSTIP:%SMTPPORT/964 --mail-rcpt user@åäö.se
+</command>
+</client>
+
+#
+# Verify data after the test has been "shot"
+<verify>
+<protocol>
+EHLO 964
+VRFY user@xn--4cab6c.se
+QUIT
+</protocol>
+</verify>
+</testcase>
diff --git a/tests/ftpserver.pl b/tests/ftpserver.pl
index 6709769d7..59a1665bd 100755
--- a/tests/ftpserver.pl
+++ b/tests/ftpserver.pl
@@ -1040,7 +1040,13 @@ sub VRFY_smtp {
             my @data = getreplydata($smtp_client);
 
             if(!@data) {
-              push @data, "250 <$username\@example.com>\r\n"
+                if ($username !~
+                    /^([a-zA-Z0-9._%+-]+)\@(([a-zA-Z0-9-]+)\.)+([a-zA-Z]{2,4})$/) {
+                  push @data, "250 <$username\@example.com>\r\n"
+                }
+                else {
+                  push @data, "250 <$username>\r\n"
+                }
             }
 
             for my $d (@data) {
-- 
cgit v1.2.3