diff options
Diffstat (limited to 'REORG.TODO/login/programs/pt_chown.c')
| -rw-r--r-- | REORG.TODO/login/programs/pt_chown.c | 215 |
1 files changed, 215 insertions, 0 deletions
diff --git a/REORG.TODO/login/programs/pt_chown.c b/REORG.TODO/login/programs/pt_chown.c new file mode 100644 index 0000000000..f12064bea5 --- /dev/null +++ b/REORG.TODO/login/programs/pt_chown.c @@ -0,0 +1,215 @@ +/* pt_chmod - helper program for `grantpt'. + Copyright (C) 1998-2017 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 Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 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 + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + <http://www.gnu.org/licenses/>. */ + +#include <argp.h> +#include <errno.h> +#include <error.h> +#include <grp.h> +#include <libintl.h> +#include <locale.h> +#include <signal.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <sys/stat.h> +#include <unistd.h> +#ifdef HAVE_LIBCAP +# include <sys/capability.h> +# include <sys/prctl.h> +#endif + +#include "pty-private.h" + +/* Get libc version number. */ +#include "../version.h" + +#define PACKAGE _libc_intl_domainname + +/* Name and version of program. */ +static void print_version (FILE *stream, struct argp_state *state); +void (*argp_program_version_hook) (FILE *, struct argp_state *) = print_version; + +/* Function to print some extra text in the help message. */ +static char *more_help (int key, const char *text, void *input); + +/* Data structure to communicate with argp functions. */ +static struct argp argp = +{ + NULL, NULL, NULL, NULL, NULL, more_help +}; + + +/* Print the version information. */ +static void +print_version (FILE *stream, struct argp_state *state) +{ + fprintf (stream, "pt_chown %s%s\n", PKGVERSION, VERSION); + fprintf (stream, gettext ("\ +Copyright (C) %s Free Software Foundation, Inc.\n\ +This is free software; see the source for copying conditions. There is NO\n\ +warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.\n\ +"), "2017"); +} + +static char * +more_help (int key, const char *text, void *input) +{ + char *cp; + char *tp; + + switch (key) + { + case ARGP_KEY_HELP_PRE_DOC: + asprintf (&cp, gettext ("\ +Set the owner, group and access permission of the slave pseudo\ + terminal corresponding to the master pseudo terminal passed on\ + file descriptor `%d'. This is the helper program for the\ + `grantpt' function. It is not intended to be run directly from\ + the command line.\n"), + PTY_FILENO); + return cp; + case ARGP_KEY_HELP_EXTRA: + /* We print some extra information. */ + if (asprintf (&tp, gettext ("\ +For bug reporting instructions, please see:\n\ +%s.\n"), REPORT_BUGS_TO) < 0) + return NULL; + if (asprintf (&cp, gettext ("\ +The owner is set to the current user, the group is set to `%s',\ + and the access permission is set to `%o'.\n\n\ +%s"), + TTY_GROUP, S_IRUSR|S_IWUSR|S_IWGRP, tp) < 0) + { + free (tp); + return NULL; + } + return cp; + default: + break; + } + return (char *) text; +} + +static int +do_pt_chown (void) +{ + char *pty; + struct stat64 st; + struct group *p; + gid_t gid; + + /* Check that PTY_FILENO is a valid master pseudo terminal. */ + pty = ptsname (PTY_FILENO); + if (pty == NULL) + return errno == EBADF ? FAIL_EBADF : FAIL_EINVAL; + + /* Check that the returned slave pseudo terminal is a + character device. */ + if (stat64 (pty, &st) < 0 || !S_ISCHR (st.st_mode)) + return FAIL_EINVAL; + + /* Get the group ID of the special `tty' group. */ + p = getgrnam (TTY_GROUP); + gid = p ? p->gr_gid : getgid (); + + /* Set the owner to the real user ID, and the group to that special + group ID. */ + if (chown (pty, getuid (), gid) < 0) + return FAIL_EACCES; + + /* Set the permission mode to readable and writable by the owner, + and writable by the group. */ + if ((st.st_mode & ACCESSPERMS) != (S_IRUSR|S_IWUSR|S_IWGRP) + && chmod (pty, S_IRUSR|S_IWUSR|S_IWGRP) < 0) + return FAIL_EACCES; + + return 0; +} + + +int +main (int argc, char *argv[]) +{ + uid_t euid = geteuid (); + uid_t uid = getuid (); + int remaining; + sigset_t signalset; + + /* Clear any signal mask from the parent process. */ + sigemptyset (&signalset); + sigprocmask (SIG_SETMASK, &signalset, NULL); + + if (argc == 1 && euid == 0) + { +#ifdef HAVE_LIBCAP + /* Drop privileges. */ + if (uid != euid) + { + static const cap_value_t cap_list[] = + { CAP_CHOWN, CAP_FOWNER }; +# define ncap_list (sizeof (cap_list) / sizeof (cap_list[0])) + cap_t caps = cap_init (); + if (caps == NULL) + return FAIL_ENOMEM; + + /* There is no reason why these should not work. */ + cap_set_flag (caps, CAP_PERMITTED, ncap_list, cap_list, CAP_SET); + cap_set_flag (caps, CAP_EFFECTIVE, ncap_list, cap_list, CAP_SET); + + int res = cap_set_proc (caps); + + cap_free (caps); + + if (__glibc_unlikely (res != 0)) + return FAIL_EXEC; + } +#endif + + /* Normal invocation of this program is with no arguments and + with privileges. */ + return do_pt_chown (); + } + + /* We aren't going to be using privileges, so drop them right now. */ + setuid (uid); + + /* Set locale via LC_ALL. */ + setlocale (LC_ALL, ""); + + /* Set the text message domain. */ + textdomain (PACKAGE); + + /* parse and process arguments. */ + argp_parse (&argp, argc, argv, 0, &remaining, NULL); + + if (remaining < argc) + { + /* We should not be called with any non-option parameters. */ + error (0, 0, gettext ("too many arguments")); + argp_help (&argp, stdout, ARGP_HELP_SEE | ARGP_HELP_EXIT_ERR, + program_invocation_short_name); + return EXIT_FAILURE; + } + + /* Check if we are properly installed. */ + if (euid != 0) + error (FAIL_EXEC, 0, gettext ("needs to be installed setuid `root'")); + + return EXIT_SUCCESS; +} |