smtp: Support the SMTPUTF8 extension in the VRFY command

lib/smtp.c

@@ -491,6 +491,12 @@ static CURLcode smtp_perform_command(struct connectdata *conn)
       char *address = NULL;
       struct hostname host = { NULL, NULL, NULL, NULL };
 
+      /* We notify the server we are sending UTF-8 data if a) it supports the
+         SMTPUTF8 extension and b) The mailbox contains UTF-8 charaacters, in
+         either the local address or host name parts. This is regardless of
+         whether the host name is encoded using IDN ACE */
+      bool utf8 = FALSE;
+
       /* 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,
@@ -498,12 +504,19 @@ static CURLcode smtp_perform_command(struct connectdata *conn)
       if(result)
         return result;
 
+      /* Establish whether we should report SMTPUTF8 to the server for this
+         mailbox as per RFC-6531 sect. 3.1 point 6 */
+      utf8 = (conn->proto.smtpc.utf8_supported) &&
+             ((host.encalloc) || (!Curl_is_ASCII_name(address)) ||
+              (!Curl_is_ASCII_name(host.name)));
+
       /* 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",
+      result = Curl_pp_sendf(&conn->proto.smtpc.pp, "VRFY %s%s%s%s",
                              address,
                              host.name ? "@" : "",
-                             host.name ? host.name : "");
+                             host.name ? host.name : "",
+                             utf8 ? " SMTPUTF8" : "");
 
       Curl_free_idnconverted_hostname(&host);
       free(address);

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 test964 test965 test966 \
+test963 test964 test965 test966 test967 test968 \
 \
 test1000 test1001 test1002 test1003 test1004 test1005 test1006 test1007 \
 test1008 test1009 test1010 test1011 test1012 test1013 test1014 test1015 \

tests/data/test967

@@ -0,0 +1,54 @@
+<testcase>
+<info>
+<keywords>
+SMTP
+VRFY
+IDN
+</keywords>
+</info>
+
+#
+# Server-side
+<reply>
+<servercmd>
+CAPA SMTPUTF8
+</servercmd>
+<data>
+252 Send some mail and I'll try my best
+</data>
+</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 with SMTPUTF8 support
+ </name>
+<command>
+smtp://%HOSTIP:%SMTPPORT/967 --mail-rcpt Användaren@åäö.se
+</command>
+</client>
+
+#
+# Verify data after the test has been "shot"
+<verify>
+<protocol>
+EHLO 967
+VRFY Användaren@xn--4cab6c.se SMTPUTF8
+QUIT
+</protocol>
+</verify>
+</testcase>

tests/data/test968

@@ -0,0 +1,51 @@
+<testcase>
+<info>
+<keywords>
+SMTP
+VRFY
+IDN
+</keywords>
+</info>
+
+#
+# Server-side
+<reply>
+<servercmd>
+CAPA SMTPUTF8
+</servercmd>
+</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 VRFY with SMTPUTF8 support
+ </name>
+<command>
+smtp://%HOSTIP:%SMTPPORT/968 --mail-rcpt Användaren
+</command>
+</client>
+
+#
+# Verify data after the test has been "shot"
+<verify>
+<protocol>
+EHLO 968
+VRFY Användaren SMTPUTF8
+QUIT
+</protocol>
+</verify>
+</testcase>

tests/ftpserver.pl

@@ -1037,13 +1037,15 @@ sub VRFY_smtp {
         sendcontrol "501 Unrecognized parameter\r\n";
     }
     else {
+        my $smtputf8 = grep /^SMTPUTF8$/, @capabilities;
+
         # Validate the username (only a valid local or external username is
         # allowed, such as user or user@example.com)
-        if ($username !~
+        if ((!$smtputf8 && $username =~
-            /^([a-zA-Z0-9._%+-]+)(\@(([a-zA-Z0-9-]+)\.)+([a-zA-Z]{2,4}))?$/) {
+            /^([a-zA-Z0-9._%+-]+)(\@(([a-zA-Z0-9-]+)\.)+([a-zA-Z]{2,4}))?$/) ||
-            sendcontrol "501 Invalid address\r\n";
+            ($smtputf8 && $username =~
-        }
+            /^([a-zA-Z0-9\x{80}-\x{ff}._%+-]+)(\@(([a-zA-Z0-9\x{80}-\x{ff}-]+)\.)+([a-zA-Z]{2,4}))?$/)) {
-        else {
+
             my @data = getreplydata($smtp_client);
 
             if(!@data) {
@@ -1060,6 +1062,9 @@ sub VRFY_smtp {
                 sendcontrol $d;
             }
         }
+        else {
+            sendcontrol "501 Invalid address\r\n";
+        }
     }
 
     return 0;