1 | /* vi: set sw=4 ts=4: */
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2 | /*
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3 | Licensed under the GPL v2, see the file LICENSE in this tarball.
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4 | */
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5 |
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6 | #include <fcntl.h>
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7 | #include <signal.h>
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8 | #include <stdio.h>
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9 | #include <stdlib.h>
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10 | #include <string.h>
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11 | #include <syslog.h>
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12 | #include <termios.h>
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13 | #include <unistd.h>
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14 | #include <utmp.h>
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15 | #include <sys/resource.h>
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16 | #include <sys/stat.h>
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17 | #include <sys/types.h>
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18 | #include <ctype.h>
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19 | #include <time.h>
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20 |
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21 | #include "busybox.h"
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22 |
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23 | /* The shell to run if none is given in the user's passwd entry. */
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24 | #ifndef DEFAULT_SHELL
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25 | #define DEFAULT_SHELL "/bin/sh"
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26 | #endif
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27 |
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28 | /* Default user. */
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29 | #define DEFAULT_USER "root"
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30 |
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31 | /* #define SYSLOG_SUCCESS */
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32 | #define SYSLOG_FAILURE
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33 |
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34 |
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35 | #if defined( SYSLOG_SUCCESS ) || defined( SYSLOG_FAILURE )
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36 | /* Log the fact that someone has run su */
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37 |
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38 | # if defined( SYSLOG_SUCCESS ) && defined( SYSLOG_FAILURE )
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39 | static void log_su (const char *successful, const char *old_user,
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40 | const char *tty)
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41 | {
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42 | syslog ( LOG_NOTICE, "%s%s on %s", successful, old_user, tty);
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43 | }
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44 | # define log_su_successful(cu, u, tty) if(!cu) log_su("", u, tty)
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45 | # define log_su_failure(cu, u, tty) if(!cu) log_su("FAILED SU ", u, tty)
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46 | # else
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47 | /* partial logging */
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48 | # if !defined( SYSLOG_SUCESS )
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49 | # define log_su_successful(cu, u, tty)
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50 | # define log_su_failure(cu, u, t) if(!cu) \
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51 | syslog(LOG_NOTICE, "FAILED SU %s on %s", u, t)
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52 | # else
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53 | # define log_su_successful(cu, u, t) if(!cu) \
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54 | syslog(LOG_NOTICE, "%s on %s", u, t)
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55 | # define log_su_failure(cu, u, tty)
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56 | # endif
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57 | # endif
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58 | #else
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59 | /* logging not used */
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60 | # define log_su_successful(cu, u, tty)
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61 | # define log_su_failure(cu, u, tty)
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62 | #endif
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63 |
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64 |
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65 | int su_main ( int argc, char **argv )
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66 | {
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67 | unsigned long flags;
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68 | char *opt_shell = 0;
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69 | char *opt_command = 0;
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70 | char *opt_username = DEFAULT_USER;
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71 | char **opt_args = 0;
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72 | struct passwd *pw;
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73 | uid_t cur_uid = getuid();
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74 |
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75 | #if defined( SYSLOG_SUCCESS ) || defined( SYSLOG_FAILURE )
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76 | const char *tty;
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77 | const char *old_user;
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78 | #endif
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79 |
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80 | flags = bb_getopt_ulflags(argc, argv, "mplc:s:",
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81 | &opt_command, &opt_shell);
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82 | #define SU_OPT_m (3)
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83 | #define SU_OPT_p (3)
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84 | #define SU_OPT_l (4)
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85 |
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86 | if (optind < argc && argv[optind][0] == '-' && argv[optind][1] == 0) {
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87 | flags |= SU_OPT_l;
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88 | ++optind;
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89 | }
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90 |
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91 | /* get user if specified */
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92 | if ( optind < argc )
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93 | opt_username = argv [optind++];
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94 |
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95 | if ( optind < argc )
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96 | opt_args = argv + optind;
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97 |
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98 | #if defined( SYSLOG_SUCCESS ) || defined( SYSLOG_FAILURE )
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99 | #ifdef CONFIG_FEATURE_UTMP
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100 | /* The utmp entry (via getlogin) is probably the best way to identify
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101 | the user, especially if someone su's from a su-shell. */
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102 | old_user = getlogin ( );
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103 | if ( !old_user )
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104 | #endif
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105 | {
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106 | /* getlogin can fail -- usually due to lack of utmp entry.
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107 | Resort to getpwuid. */
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108 | pw = getpwuid ( cur_uid );
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109 | old_user = ( pw ? pw->pw_name : "" );
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110 | }
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111 | tty = ttyname ( 2 );
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112 | if(!tty)
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113 | tty = "none";
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114 |
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115 | openlog ( bb_applet_name, 0, LOG_AUTH );
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116 | #endif
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117 |
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118 | pw = getpwnam ( opt_username );
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119 | if ( !pw )
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120 | bb_error_msg_and_die ( "user %s does not exist", opt_username );
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121 |
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122 | /* Make sure pw->pw_shell is non-NULL. It may be NULL when NEW_USER
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123 | is a username that is retrieved via NIS (YP), but that doesn't have
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124 | a default shell listed. */
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125 | if ( !pw->pw_shell || !pw->pw_shell [0] )
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126 | pw->pw_shell = (char *) DEFAULT_SHELL;
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127 |
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128 | if ((( cur_uid == 0 ) || correct_password ( pw ))) {
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129 | log_su_successful(pw->pw_uid, old_user, tty );
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130 | } else {
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131 | log_su_failure (pw->pw_uid, old_user, tty );
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132 | bb_error_msg_and_die ( "incorrect password" );
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133 | }
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134 |
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135 | #if defined( SYSLOG_SUCCESS ) || defined( SYSLOG_FAILURE )
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136 | closelog();
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137 | #endif
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138 |
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139 | if ( !opt_shell && (flags & SU_OPT_p))
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140 | opt_shell = getenv ( "SHELL" );
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141 |
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142 | if ( opt_shell && cur_uid && restricted_shell ( pw->pw_shell )) {
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143 | /* The user being su'd to has a nonstandard shell, and so is
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144 | probably a uucp account or has restricted access. Don't
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145 | compromise the account by allowing access with a standard
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146 | shell. */
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147 | fputs ( "using restricted shell\n", stderr );
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148 | opt_shell = 0;
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149 | }
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150 |
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151 | if ( !opt_shell )
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152 | opt_shell = pw->pw_shell;
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153 |
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154 | change_identity ( pw );
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155 | setup_environment(opt_shell, flags & SU_OPT_l, !(flags & SU_OPT_p), pw);
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156 | #if ENABLE_SELINUX
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157 | set_current_security_context(NULL);
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158 | #endif
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159 | run_shell(opt_shell, flags & SU_OPT_l, opt_command, (const char**)opt_args);
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160 |
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161 | return EXIT_FAILURE;
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162 | }
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