| 1 | /* vi: set sw=4 ts=4: */
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| 2 | /*
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| 3 | * Mini sulogin implementation for busybox
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| 4 | *
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| 5 | * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
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| 6 | */
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| 7 |
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| 8 | #include <syslog.h>
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| 9 |
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| 10 | #include "libbb.h"
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| 11 |
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| 12 | static const char *const forbid[] = {
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| 13 | "ENV",
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| 14 | "BASH_ENV",
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| 15 | "HOME",
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| 16 | "IFS",
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| 17 | "PATH",
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| 18 | "SHELL",
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| 19 | "LD_LIBRARY_PATH",
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| 20 | "LD_PRELOAD",
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| 21 | "LD_TRACE_LOADED_OBJECTS",
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| 22 | "LD_BIND_NOW",
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| 23 | "LD_AOUT_LIBRARY_PATH",
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| 24 | "LD_AOUT_PRELOAD",
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| 25 | "LD_NOWARN",
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| 26 | "LD_KEEPDIR",
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| 27 | (char *) 0
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| 28 | };
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| 29 |
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| 30 |
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| 31 | static void catchalarm(int ATTRIBUTE_UNUSED junk)
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| 32 | {
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| 33 | exit(EXIT_FAILURE);
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| 34 | }
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| 35 |
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| 36 |
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| 37 | int sulogin_main(int argc, char **argv);
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| 38 | int sulogin_main(int argc, char **argv)
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| 39 | {
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| 40 | char *cp;
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| 41 | int timeout = 0;
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| 42 | char *timeout_arg;
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| 43 | const char *const *p;
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| 44 | struct passwd *pwd;
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| 45 | const char *shell;
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| 46 | #if ENABLE_FEATURE_SHADOWPASSWDS
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| 47 | /* Using _r function to avoid pulling in static buffers */
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| 48 | char buffer[256];
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| 49 | struct spwd spw;
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| 50 | struct spwd *result;
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| 51 | #endif
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| 52 |
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| 53 | logmode = LOGMODE_BOTH;
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| 54 | openlog(applet_name, 0, LOG_AUTH);
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| 55 |
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| 56 | if (getopt32(argv, "t:", &timeout_arg)) {
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| 57 | timeout = xatoi_u(timeout_arg);
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| 58 | }
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| 59 |
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| 60 | if (argv[optind]) {
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| 61 | close(0);
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| 62 | close(1);
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| 63 | dup(xopen(argv[optind], O_RDWR));
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| 64 | close(2);
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| 65 | dup(0);
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| 66 | }
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| 67 |
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| 68 | if (!isatty(0) || !isatty(1) || !isatty(2)) {
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| 69 | logmode = LOGMODE_SYSLOG;
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| 70 | bb_error_msg_and_die("not a tty");
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| 71 | }
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| 72 |
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| 73 | /* Clear out anything dangerous from the environment */
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| 74 | for (p = forbid; *p; p++)
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| 75 | unsetenv(*p);
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| 76 |
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| 77 | signal(SIGALRM, catchalarm);
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| 78 |
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| 79 | pwd = getpwuid(0);
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| 80 | if (!pwd) {
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| 81 | goto auth_error;
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| 82 | }
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| 83 |
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| 84 | #if ENABLE_FEATURE_SHADOWPASSWDS
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| 85 | if (getspnam_r(pwd->pw_name, &spw, buffer, sizeof(buffer), &result)) {
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| 86 | goto auth_error;
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| 87 | }
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| 88 | pwd->pw_passwd = spw.sp_pwdp;
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| 89 | #endif
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| 90 |
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| 91 | while (1) {
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| 92 | /* cp points to a static buffer that is zeroed every time */
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| 93 | cp = bb_askpass(timeout,
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| 94 | "Give root password for system maintenance\n"
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| 95 | "(or type Control-D for normal startup):");
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| 96 |
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| 97 | if (!cp || !*cp) {
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| 98 | bb_info_msg("Normal startup");
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| 99 | return 0;
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| 100 | }
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| 101 | if (strcmp(pw_encrypt(cp, pwd->pw_passwd), pwd->pw_passwd) == 0) {
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| 102 | break;
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| 103 | }
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| 104 | bb_do_delay(FAIL_DELAY);
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| 105 | bb_error_msg("login incorrect");
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| 106 | }
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| 107 | memset(cp, 0, strlen(cp));
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| 108 | signal(SIGALRM, SIG_DFL);
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| 109 |
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| 110 | bb_info_msg("System Maintenance Mode");
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| 111 |
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| 112 | USE_SELINUX(renew_current_security_context());
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| 113 |
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| 114 | shell = getenv("SUSHELL");
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| 115 | if (!shell) shell = getenv("sushell");
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| 116 | if (!shell) {
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| 117 | shell = "/bin/sh";
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| 118 | if (pwd->pw_shell[0])
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| 119 | shell = pwd->pw_shell;
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| 120 | }
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| 121 | run_shell(shell, 1, 0, 0);
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| 122 | /* never returns */
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| 123 |
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| 124 | auth_error:
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| 125 | bb_error_msg_and_die("no password entry for 'root'");
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| 126 | }
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