Add setsockopt(sd, SOL_SOCKET, SO_PEERCRED, NULL, 0) to disable

	initial handshake on AF_LOCAL sockets.
	* fhandler.h (class fhandler_socket): Add no_getpeereid status flag.
	(fhandler_socket::af_local_set_no_getpeereid): New prototype.
	* fhandler_socket.cc (fhandler_socket::af_local_connect): Skip handshake
	if no_getpeereid is set.  Add debug output.
	(fhandler_socket::af_local_accept): Likewise.
	(fhandler_socket::af_local_set_no_getpeereid): New function.
	(fhandler_socket::af_local_copy): Copy no_getpeereid.
	(fhandler_socket::getpeereid): Fail if no_getpeereid is set.
	* net.cc (cygwin_setsockopt): Add SO_PEERCRED for AF_LOCAL/SOCK_STREAM
	sockets.  Add comment to explain why we need it.
	* include/cygwin/version.h (CYGWIN_VERSION_API_MINOR): Bump.

1 files changed, 33 insertions, 2 deletions

diff --git a/winsup/cygwin/fhandler_socket.cc b/winsup/cygwin/fhandler_socket.cc
index e2750ea72..ff150448e 100644
--- a/winsup/cygwin/fhandler_socket.cc
+++ b/winsup/cygwin/fhandler_socket.cc
@@ -401,7 +401,10 @@ fhandler_socket::af_local_connect ()
   if (get_addr_family () != AF_LOCAL || get_socket_type () != SOCK_STREAM)
     return 0;
 
-  debug_printf ("af_local_connect called");
+  debug_printf ("af_local_connect called, no_getpeereid=%d", no_getpeereid ());
+  if (no_getpeereid ())
+    return 0;
+
   connect_state (connect_credxchg);
   af_local_setblocking (orig_async_io, orig_is_nonblocking);
   if (!af_local_send_secret () || !af_local_recv_secret ()
@@ -421,7 +424,10 @@ fhandler_socket::af_local_accept ()
 {
   bool orig_async_io, orig_is_nonblocking;
 
-  debug_printf ("af_local_accept called");
+  debug_printf ("af_local_accept called, no_getpeereid=%d", no_getpeereid ());
+  if (no_getpeereid ())
+    return 0;
+
   connect_state (connect_credxchg);
   af_local_setblocking (orig_async_io, orig_is_nonblocking);
   if (!af_local_recv_secret () || !af_local_send_secret ()
@@ -437,6 +443,25 @@ fhandler_socket::af_local_accept ()
   return 0;
 }
 
+int
+fhandler_socket::af_local_set_no_getpeereid ()
+{
+  if (get_addr_family () != AF_LOCAL || get_socket_type () != SOCK_STREAM)
+    {
+      set_errno (EINVAL);
+      return -1;
+    }
+  if (connect_state () != unconnected)
+    {
+      set_errno (EALREADY);
+      return -1;
+    }
+
+  debug_printf ("no_getpeereid set");
+  no_getpeereid (true);
+  return 0;
+}
+
 void
 fhandler_socket::af_local_set_cred ()
 {
@@ -461,6 +486,7 @@ fhandler_socket::af_local_copy (fhandler_socket *sock)
   sock->sec_peer_pid = sec_peer_pid;
   sock->sec_peer_uid = sec_peer_uid;
   sock->sec_peer_gid = sec_peer_gid;
+  sock->no_getpeereid (no_getpeereid ());
 }
 
 void
@@ -2303,6 +2329,11 @@ fhandler_socket::getpeereid (pid_t *pid, uid_t *euid, gid_t *egid)
       set_errno (EINVAL);
       return -1;
     }
+  if (no_getpeereid ())
+    {
+      set_errno (ENOTSUP);
+      return -1;
+    }
   if (connect_state () != connected)
     {
       set_errno (ENOTCONN);