[821] | 1 | /* vi: set sw=4 ts=4: */
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[1765] | 2 | /*
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| 3 | * Mini sulogin implementation for busybox
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| 4 | *
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[2725] | 5 | * Licensed under GPLv2 or later, see file LICENSE in this source tree.
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[1765] | 6 | */
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[3621] | 7 | //config:config SULOGIN
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| 8 | //config: bool "sulogin"
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| 9 | //config: default y
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| 10 | //config: select FEATURE_SYSLOG
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| 11 | //config: help
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| 12 | //config: sulogin is invoked when the system goes into single user
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| 13 | //config: mode (this is done through an entry in inittab).
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[1765] | 14 |
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[3621] | 15 | //applet:IF_SULOGIN(APPLET(sulogin, BB_DIR_SBIN, BB_SUID_DROP))
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| 16 |
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| 17 | //kbuild:lib-$(CONFIG_SULOGIN) += sulogin.o
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| 18 |
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[3232] | 19 | //usage:#define sulogin_trivial_usage
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| 20 | //usage: "[-t N] [TTY]"
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| 21 | //usage:#define sulogin_full_usage "\n\n"
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| 22 | //usage: "Single user login\n"
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| 23 | //usage: "\n -t N Timeout"
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| 24 |
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[2725] | 25 | #include "libbb.h"
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[821] | 26 | #include <syslog.h>
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| 27 |
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[2725] | 28 | int sulogin_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
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| 29 | int sulogin_main(int argc UNUSED_PARAM, char **argv)
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[821] | 30 | {
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| 31 | int timeout = 0;
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| 32 | struct passwd *pwd;
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[1765] | 33 | const char *shell;
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[821] | 34 |
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[3621] | 35 | /* Note: sulogin is not a suid app. It is meant to be run by init
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| 36 | * for single user / emergency mode. init starts it as root.
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| 37 | * Normal users (potentially malisious ones) can only run it under
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| 38 | * their UID, therefore no paranoia here is warranted:
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| 39 | * $LD_LIBRARY_PATH in env, TTY = /dev/sda
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| 40 | * are no more dangerous here than in e.g. cp applet.
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| 41 | */
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| 42 |
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[1765] | 43 | logmode = LOGMODE_BOTH;
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| 44 | openlog(applet_name, 0, LOG_AUTH);
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| 45 |
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[2725] | 46 | opt_complementary = "t+"; /* -t N */
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| 47 | getopt32(argv, "t:", &timeout);
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| 48 | argv += optind;
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[1765] | 49 |
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[2725] | 50 | if (argv[0]) {
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[1765] | 51 | close(0);
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| 52 | close(1);
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[2725] | 53 | dup(xopen(argv[0], O_RDWR));
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[1765] | 54 | close(2);
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| 55 | dup(0);
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[821] | 56 | }
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[1765] | 57 |
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| 58 | pwd = getpwuid(0);
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| 59 | if (!pwd) {
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[3621] | 60 | bb_error_msg_and_die("no password entry for root");
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[821] | 61 | }
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[1765] | 62 |
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[821] | 63 | while (1) {
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[2725] | 64 | int r;
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| 65 |
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[3621] | 66 | r = ask_and_check_password_extended(pwd, timeout,
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| 67 | "Give root password for system maintenance\n"
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| 68 | "(or type Control-D for normal startup):"
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| 69 | );
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| 70 | if (r < 0) {
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| 71 | /* ^D, ^C, timeout, or read error */
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| 72 | bb_error_msg("normal startup");
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[1765] | 73 | return 0;
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[821] | 74 | }
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[3621] | 75 | if (r > 0) {
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[821] | 76 | break;
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| 77 | }
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[3232] | 78 | bb_do_delay(LOGIN_FAIL_DELAY);
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[3621] | 79 | bb_error_msg("Login incorrect");
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[821] | 80 | }
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| 81 |
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[3621] | 82 | bb_error_msg("starting shell for system maintenance");
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[821] | 83 |
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[2725] | 84 | IF_SELINUX(renew_current_security_context());
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[821] | 85 |
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[1765] | 86 | shell = getenv("SUSHELL");
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[2725] | 87 | if (!shell)
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| 88 | shell = getenv("sushell");
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| 89 | if (!shell)
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| 90 | shell = pwd->pw_shell;
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[1765] | 91 |
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[2725] | 92 | /* Exec login shell with no additional parameters. Never returns. */
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| 93 | run_shell(shell, 1, NULL, NULL);
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[821] | 94 | }
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