catch insidious syntax error

1 files changed, 3 insertions, 0 deletions

diff --git a/qmail-smtpd.c b/qmail-smtpd.c
index 7d062a2..1064008 100644
--- a/qmail-smtpd.c
+++ b/qmail-smtpd.c
@@ -171,6 +171,7 @@ char *arg;
     arg += i + 1;
   else { /* partner should go read rfc 821 */
     terminator = ' ';
+/* The following fails insidiously if there's no ':' */
     arg += str_chr(arg,':');
     if (*arg == ':') ++arg;
     while (*arg == ' ') ++arg;
@@ -211,7 +212,9 @@ char *arg;
           }
   }
 
+/* returning 0 will provoke a "555 syntax error" */
   if (addr.len > 900) return 0;
+  if (addr.len == 0 || addr.s[0] == 0) return 0;
   return 1;
 }