1 files changed, 50 insertions, 0 deletions
diff --git a/util/strgutil.c b/util/strgutil.c
index 402881a6e..620fb33bc 100644
--- a/util/strgutil.c
+++ b/util/strgutil.c
@@ -455,6 +455,56 @@ string_count_chr( const char *string, int c )
     return count;
 }
 
+
+/* Check whether the string has characters not valid in an RFC-822
+   address.  To cope with OpenPGP we ignore non-ascii characters
+   so that for example umlauts are legal in an email address.  An
+   OpenPGP user ID must be utf-8 encoded but there is no strict
+   requirement for RFC-822.  Thus to avoid IDNA encoding we put the
+   address verbatim as utf-8 into the user ID under the assumption
+   that mail programs handle IDNA at a lower level and take OpenPGP
+   user IDs as utf-8.  Note that we can't do an utf-8 encoding
+   checking here because in keygen.c this function is called with the
+   native encoding and native to utf-8 encoding is only done  later.  */
+int
+has_invalid_email_chars (const char *s)
+{
+  int at_seen=0;
+  const char *valid_chars=
+    "01234567890_-.abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";
+
+  for ( ; *s; s++ )
+    {
+      if ( *s & 0x80 )
+        continue; /* We only care about ASCII.  */
+      if ( *s == '@' )
+        at_seen=1;
+      else if ( !at_seen && !( !!strchr( valid_chars, *s ) || *s == '+' ) )
+        return 1;
+      else if ( at_seen && !strchr( valid_chars, *s ) )
+        return 1;
+    }
+  return 0;
+}
+
+
+/* Check whether NAME represents a valid mailbox according t
+   RFC822. Returns true if so.  */
+int
+is_valid_mailbox (const char *name)
+{
+  return !( !name
+            || !*name
+            || has_invalid_email_chars (name)
+            || string_count_chr (name,'@') != 1
+            || *name == '@'
+            || name[strlen(name)-1] == '@'
+            || name[strlen(name)-1] == '.'
+            || strstr (name, "..") );
+}
+
+
+
 #ifdef USE_GNUPG_ICONV
 static void
 handle_iconv_error (const char *to, const char *from, int use_fallback)