diff options
Diffstat (limited to 'loginutils/su.c')
-rw-r--r-- | loginutils/su.c | 90 |
1 files changed, 90 insertions, 0 deletions
diff --git a/loginutils/su.c b/loginutils/su.c new file mode 100644 index 000000000..a23ee932b --- /dev/null +++ b/loginutils/su.c @@ -0,0 +1,90 @@ +/* vi: set sw=4 ts=4: */ +/* + * Mini su implementation for busybox + * + * Licensed under the GPL v2 or later, 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 = getopt32(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(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; +} |