diff options
Diffstat (limited to 'winsup/cygwin/fhandler_socket.cc')
| -rw-r--r-- | winsup/cygwin/fhandler_socket.cc | 22 |
1 files changed, 17 insertions, 5 deletions
diff --git a/winsup/cygwin/fhandler_socket.cc b/winsup/cygwin/fhandler_socket.cc index c0df1fb66..2a39d387e 100644 --- a/winsup/cygwin/fhandler_socket.cc +++ b/winsup/cygwin/fhandler_socket.cc @@ -911,17 +911,29 @@ fhandler_socket::bind (const struct sockaddr *name, int namelen) (const char *) &on, sizeof on); debug_printf ("%d = setsockopt (SO_EXCLUSIVEADDRUSE), %E", ret); } - else + else if (!wincap.has_enhanced_socket_security ()) { debug_printf ("SO_REUSEADDR set"); /* There's a bug in SO_REUSEADDR handling in WinSock. Per standards, we must not be able to reuse a complete duplicate of a local TCP address (same IP, same port), even if SO_REUSEADDR has been set. That's unfortunately - possible in WinSock. So we're testing here if the local - address is already in use and don't bind, if so. This - only works for OSes with IP Helper support. */ - if (get_socket_type () == SOCK_STREAM + possible in WinSock. + + So we're testing here if the local address is already in + use and don't bind, if so. This only works for OSes with + IP Helper support and is, of course, still prone to races. + + However, we don't have to do this on systems supporting + "enhanced socket security" (2K3 and later). On these + systems the default binding behaviour is exactly as you'd + expect for SO_REUSEADDR, while setting SO_REUSEADDR re-enables + the wrong behaviour. So all we have to do on these newer + systems is never to set SO_REUSEADDR but only to note that + it has been set for the above SO_EXCLUSIVEADDRUSE setting. + See setsockopt() in net.cc. */ + if (name->sa_family == AF_INET + && get_socket_type () == SOCK_STREAM && wincap.has_ip_helper_lib () && address_in_use ((struct sockaddr_in *) name)) { |