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Diffstat (limited to 'login/programs/pt_chown.c')
-rw-r--r--login/programs/pt_chown.c88
1 files changed, 88 insertions, 0 deletions
diff --git a/login/programs/pt_chown.c b/login/programs/pt_chown.c
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+++ b/login/programs/pt_chown.c
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+/* 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;
+}