| /* vi: set sw=4 ts=4: */ |
| /* |
| * Mini su implementation for busybox |
| * |
| * Licensed under the GPL v2, see the file LICENSE in this tarball. |
| */ |
| |
| #include "busybox.h" |
| #include <syslog.h> |
| |
| int su_main ( int argc, char **argv ) |
| { |
| unsigned long flags; |
| char *opt_shell = 0; |
| char *opt_command = 0; |
| char *opt_username = "root"; |
| char **opt_args = 0; |
| struct passwd *pw; |
| uid_t cur_uid = getuid(); |
| const char *tty; |
| char *old_user; |
| |
| flags = bb_getopt_ulflags(argc, argv, "mplc:s:", &opt_command, &opt_shell); |
| #define SU_OPT_mp (3) |
| #define SU_OPT_l (4) |
| |
| if (optind < argc && argv[optind][0] == '-' && argv[optind][1] == 0) { |
| flags |= SU_OPT_l; |
| ++optind; |
| } |
| |
| /* get user if specified */ |
| if (optind < argc) opt_username = argv [optind++]; |
| |
| if (optind < argc) opt_args = argv + optind; |
| |
| if (ENABLE_SU_SYSLOG) { |
| /* The utmp entry (via getlogin) is probably the best way to identify |
| the user, especially if someone su's from a su-shell. |
| But getlogin can fail -- usually due to lack of utmp entry. |
| in this case resort to getpwuid. */ |
| old_user = xstrdup(USE_FEATURE_UTMP(getlogin() ? : ) (pw = getpwuid(cur_uid)) ? pw->pw_name : ""); |
| tty = ttyname(2) ? : "none"; |
| openlog(bb_applet_name, 0, LOG_AUTH); |
| } |
| |
| pw = getpwnam(opt_username); |
| if (!pw) bb_error_msg_and_die("Unknown id: %s", opt_username); |
| |
| /* Make sure pw->pw_shell is non-NULL. It may be NULL when NEW_USER |
| is a username that is retrieved via NIS (YP), but that doesn't have |
| a default shell listed. */ |
| if (!pw->pw_shell || !pw->pw_shell[0]) pw->pw_shell = (char *)DEFAULT_SHELL; |
| |
| if ((cur_uid == 0) || correct_password(pw)) { |
| if (ENABLE_SU_SYSLOG) |
| syslog(LOG_NOTICE, "+ %s %s:%s", tty, old_user, opt_username); |
| } else { |
| if (ENABLE_SU_SYSLOG) |
| syslog(LOG_NOTICE, "- %s %s:%s", tty, old_user, opt_username); |
| bb_error_msg_and_die("incorrect password"); |
| } |
| |
| if (ENABLE_FEATURE_CLEAN_UP && ENABLE_SU_SYSLOG) { |
| closelog(); |
| free(old_user); |
| } |
| |
| if (!opt_shell && (flags & SU_OPT_mp)) opt_shell = getenv("SHELL"); |
| |
| if (opt_shell && cur_uid && restricted_shell(pw->pw_shell)) { |
| /* The user being su'd to has a nonstandard shell, and so is |
| probably a uucp account or has restricted access. Don't |
| compromise the account by allowing access with a standard |
| shell. */ |
| bb_error_msg("using restricted shell"); |
| opt_shell = 0; |
| } |
| |
| if (!opt_shell) opt_shell = pw->pw_shell; |
| |
| change_identity(pw); |
| setup_environment(opt_shell, flags & SU_OPT_l, !(flags & SU_OPT_mp), pw); |
| USE_SELINUX(set_current_security_context(NULL);) |
| |
| /* Never returns */ |
| run_shell(opt_shell, flags & SU_OPT_l, opt_command, (const char**)opt_args); |
| |
| return EXIT_FAILURE; |
| } |