* cygheap.h (cygheap_user::issetuid): New method.

* dtable.cc (dtable::vfork_child_dup): Use new method to determine if we are in
"setuid mode."
* fork.cc (fork_parent): Ditto.
* spawn.cc (spawn_guts): Ditto.
* syscalls.cc (seteuid32): Ditto.
(setegid32): Ditto.
* environ.cc (spenv::retrieve): (Suggested by Pierre Humblet) Do potential
recalculation of cygheap_user stuff when in setuid mode.  Return special value
when environment variable exists but should not be added.
(build_env): Don't add retrieved value to dstp if it is 'dont_add'.

1 files changed, 3 insertions, 4 deletions

diff --git a/winsup/cygwin/fork.cc b/winsup/cygwin/fork.cc
index 7a7cac0ba..e6fb91037 100644
--- a/winsup/cygwin/fork.cc
+++ b/winsup/cygwin/fork.cc
@@ -441,7 +441,7 @@ fork_parent (HANDLE& hParent, dll *&first_dll,
   si.cbReserved2 = sizeof(ch);
 
   /* Remove impersonation */
-  if (cygheap->user.impersonated && cygheap->user.token != INVALID_HANDLE_VALUE)
+  if (cygheap->user.issetuid ())
     RevertToSelf ();
 
   ch.parent = hParent;
@@ -490,8 +490,7 @@ fork_parent (HANDLE& hParent, dll *&first_dll,
       ForceCloseHandle(subproc_ready);
       ForceCloseHandle(forker_finished);
       /* Restore impersonation */
-      if (cygheap->user.impersonated
-	  && cygheap->user.token != INVALID_HANDLE_VALUE)
+      if (cygheap->user.issetuid ())
 	ImpersonateLoggedOnUser (cygheap->user.token);
       cygheap_setup_for_child_cleanup (newheap, &ch, 0);
       return -1;
@@ -519,7 +518,7 @@ fork_parent (HANDLE& hParent, dll *&first_dll,
   strcpy(forked->progname, myself->progname);
 
   /* Restore impersonation */
-  if (cygheap->user.impersonated && cygheap->user.token != INVALID_HANDLE_VALUE)
+  if (cygheap->user.issetuid ())
     ImpersonateLoggedOnUser (cygheap->user.token);
 
   ProtectHandle (pi.hThread);