1 files changed, 88 insertions, 0 deletions
diff --git a/login/programs/pt_chown.c b/login/programs/pt_chown.c
new file mode 100644
index 0000000000..dbf79fc6ad
--- /dev/null
+++ b/login/programs/pt_chown.c
@@ -0,0 +1,88 @@
+/* Copyright (C) 1998 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by C. Scott Ananian <cananian@alumni.princeton.edu>, 1998.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Library General Public License as
+   published by the Free Software Foundation; either version 2 of the
+   License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Library General Public License for more details.
+
+   You should have received a copy of the GNU Library General Public
+   License along with the GNU C Library; see the file COPYING.LIB.  If not,
+   write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+   Boston, MA 02111-1307, USA.  */
+
+/* pt_chmod.c ... securely implement grantpt in user-land.  */
+
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <errno.h>
+#include <stdio.h>
+#include <grp.h>
+
+#include "pty-internal.h"
+#define Str(x) _Str(x)
+#define _Str(x) #x
+
+void
+usage (void)
+{
+  fprintf (stderr, _("usage: pt_chown FD>&%s\n"
+		     "This program is used internally by grantpt(3).\n"),
+	   Str (PTY_FD));
+  exit (0);
+}
+
+void
+bad_installation (void)
+{
+  fputs (_("pt_chown: installation problem: "
+	   "This program needs to be setuid root.\n"), stderr);
+  exit (FAIL_EXEC);
+}
+
+int
+main (int argc, char **argv)
+{
+  struct group *grp;
+  struct stat s;
+  char *pty;
+  gid_t gid;
+  uid_t uid;
+
+  if (argc != 1)
+    usage ();
+  if (geteuid () != 0)
+    bad_installation ();
+
+  grp = getgrnam (TTY_GROUP);
+  gid = grp ? grp->gr_gid : getgid ();
+  uid = getuid ();
+
+  /* Check that fd is a valid pty master -- call ptsname().  */
+  pty = ptsname (PTY_FD);
+  if (pty == NULL)
+    return errno == EBADF ? FAIL_EBADF : FAIL_EINVAL;
+  close (PTY_FD);
+
+  /* Check that target file is a character device.  */
+  if (stat (pty, &s))
+    return FAIL_EINVAL; /* This should only fail if pty doesn't exist.  */
+  if (!S_ISCHR (s.st_mode))
+    return FAIL_EINVAL;
+
+  if (chmod (pty, 0620))
+    return FAIL_EACCES;  /* XXX: Probably not true. */
+
+  if (chown (pty, uid, gid))
+    return FAIL_EACCES;
+
+  return 0;
+}