[821] | 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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