diff -ur Linux-PAM-1.1.1.orig/modules/pam_xauth/pam_xauth.c Linux-PAM-1.1.1/modules/pam_xauth/pam_xauth.c
--- Linux-PAM-1.1.1.orig/modules/pam_xauth/pam_xauth.c	2009-11-04 13:04:53.000000000 +0100
+++ Linux-PAM-1.1.1/modules/pam_xauth/pam_xauth.c	2009-12-30 17:14:59.000000000 +0100
@@ -88,7 +88,7 @@
  * given input on stdin, and storing any output it generates. */
 static int
 run_coprocess(const char *input, char **output,
-	      uid_t uid, gid_t gid, const char *command, ...)
+	      uid_t uid, gid_t gid, const char *name, const char *command, ...)
 {
 	int ipipe[2], opipe[2], i;
 	char buf[LINE_MAX];
@@ -127,7 +127,11 @@
 		int maxopened;
 		/* Drop privileges. */
 		setgid(gid);
+               /* Mandrake Linux specific:
+                * we need to set the extra groups because in high security levels
+                * access to /usr/X11R6/bin dir is controlled by a group */
 		setgroups(0, NULL);
+                initgroups(name, gid);
 		setuid(uid);
 		/* Initialize the argument list. */
 		memset(args, 0, sizeof(args));
@@ -154,6 +158,7 @@
 		}
 		/* Run the command. */
 		execv(command, args);
+		syslog(LOG_ERR, "pam_xauth: execvp of %s failed: %m", command);
 		/* Never reached. */
 		_exit(1);
 	}
@@ -464,7 +469,7 @@
 			   (unsigned long) getuid(), (unsigned long) getgid());
 	}
 	if (run_coprocess(NULL, &cookie,
-			  getuid(), getgid(),
+			  getuid(), getgid(), rpwd->pw_name,
 			  xauth, "-f", cookiefile, "nlist", display,
 			  NULL) == 0) {
 		int save_errno;
@@ -522,7 +527,7 @@
 						       (unsigned long) getgid());
 					}
 					run_coprocess(NULL, &cookie,
-						      getuid(), getgid(),
+						      getuid(), getgid(), rpwd->pw_name,
 						      xauth, "-f", cookiefile,
 						      "nlist", t, NULL);
 				}
@@ -670,7 +675,7 @@
 				  (unsigned long) tpwd->pw_gid);
 		}
 		run_coprocess(cookie, &tmp,
-			      tpwd->pw_uid, tpwd->pw_gid,
+			      tpwd->pw_uid, tpwd->pw_gid, tpwd->pw_name,
 			      xauth, "-f", cookiefile, "nmerge", "-", NULL);
 
 		/* We don't need to keep a copy of these around any more. */