Fix: a non ascii byte will trigger BadAddress error

If a byte in DBusString *unescaped isn't a ascii byte, which will be
cast to char (signed char on most of platform), so that's the issue
unsigned char cast to signed char. e.g. "\303\266" is a valid unicode
character, if everything goes right, it will be escaped to "%c3%b6".
However, in fact, it escaped to "%<garbage-byte>3%<garbage-byte>6".

_dbus_string_append_byte_as_hex() take an int parameter, so negative
byte is valid, but cause get a negative index in array. So garbage value
will get. e.g. '\303' --> hexdigits[((signed byte)(-61)) >> 4] is
hexdigits[-4].

Bug: https://bugs.freedesktop.org/show_bug.cgi?id=53499
Sgne-off-by: Chengwei Yang <chengwei.yang@intel.com>
[fixed whitespace -smcv]
Reviewed-by: Simon McVittie <simon.mcvittie@collabora.co.uk>

1 files changed, 3 insertions, 3 deletions

diff --git a/dbus/dbus-address.c b/dbus/dbus-address.c
index 90484dc1..f3d48d0a 100644
--- a/dbus/dbus-address.c
+++ b/dbus/dbus-address.c
@@ -104,15 +104,15 @@ dbus_bool_t
 _dbus_address_append_escaped (DBusString       *escaped,
                               const DBusString *unescaped)
 {
-  const char *p;
-  const char *end;
+  const unsigned char *p;
+  const unsigned char *end;
   dbus_bool_t ret;
   int orig_len;
 
   ret = FALSE;
 
   orig_len = _dbus_string_get_length (escaped);
-  p = _dbus_string_get_const_data (unescaped);
+  p = (const unsigned char *) _dbus_string_get_const_data (unescaped);
   end = p + _dbus_string_get_length (unescaped);
   while (p != end)
     {