diff options
Diffstat (limited to 'login/programs/pt_chown.c')
-rw-r--r-- | login/programs/pt_chown.c | 88 |
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 0000000..dbf79fc --- /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; +} |