1303 files changed, 32187 insertions, 57138 deletions
diff --git a/loginutils/su.c b/loginutils/su.c index c51f26f..24ffbde 100644 --- a/loginutils/su.c +++ b/loginutils/su.c @@ -4,19 +4,44 @@ * * Licensed under GPLv2 or later, see file LICENSE in this source tree. */ - -#include "libbb.h" -#include <syslog.h> +//config:config SU +//config: bool "su" +//config: default y +//config: select FEATURE_SYSLOG +//config: help +//config: su is used to become another user during a login session. +//config: Invoked without a username, su defaults to becoming the super user. +//config: +//config: Note that Busybox binary must be setuid root for this applet to +//config: work properly. +//config: +//config:config FEATURE_SU_SYSLOG +//config: bool "Enable su to write to syslog" +//config: default y +//config: depends on SU +//config: +//config:config FEATURE_SU_CHECKS_SHELLS +//config: bool "Enable su to check user's shell to be listed in /etc/shells" +//config: depends on SU +//config: default y + +//applet:/* Needs to be run by root or be suid root - needs to change uid and gid: */ +//applet:IF_SU(APPLET(su, BB_DIR_BIN, BB_SUID_REQUIRE)) + +//kbuild:lib-$(CONFIG_SU) += su.o //usage:#define su_trivial_usage -//usage: "[OPTIONS] [-] [USER]" +//usage: "[-lmp] [-] [-s SH] [USER [SCRIPT ARGS / -c 'CMD' ARG0 ARGS]]" //usage:#define su_full_usage "\n\n" //usage: "Run shell under USER (by default, root)\n" -//usage: "\n -,-l Clear environment, run shell as login shell" +//usage: "\n -,-l Clear environment, go to home dir, run shell as login shell" //usage: "\n -p,-m Do not set new $HOME, $SHELL, $USER, $LOGNAME" //usage: "\n -c CMD Command to pass to 'sh -c'" //usage: "\n -s SH Shell to use instead of user's default" +#include "libbb.h" +#include <syslog.h> + #if ENABLE_FEATURE_SU_CHECKS_SHELLS /* Return 1 if SHELL is a restricted shell (one not returned by * getusershell), else 0, meaning it is a standard shell. */ @@ -56,8 +81,12 @@ int su_main(int argc UNUSED_PARAM, char **argv) #endif const char *old_user; + /* Note: we don't use "'+': stop at first non-option" idiom here. + * For su, "SCRIPT ARGS" or "-c CMD ARGS" do not stop option parsing: + * ARGS starting with dash will be treated as su options, + * not passed to shell. (Tested on util-linux 2.28). + */ flags = getopt32(argv, "mplc:s:", &opt_command, &opt_shell); - //argc -= optind; argv += optind; if (argv[0] && LONE_DASH(argv[0])) { @@ -101,6 +130,7 @@ int su_main(int argc UNUSED_PARAM, char **argv) if (ENABLE_FEATURE_SU_SYSLOG) syslog(LOG_NOTICE, "%c %s %s:%s", '-', tty, old_user, opt_username); + bb_do_delay(LOGIN_FAIL_DELAY); bb_error_msg_and_die("incorrect password"); } @@ -136,8 +166,29 @@ int su_main(int argc UNUSED_PARAM, char **argv) pw); IF_SELINUX(set_current_security_context(NULL);) + if (opt_command) { + *--argv = opt_command; + *--argv = (char*)"-c"; + } + + /* A nasty ioctl exists which can stuff data into input queue: + * #include <sys/ioctl.h> + * int main() { + * const char *msg = "echo $UID\n"; + * while (*msg) ioctl(0, TIOCSTI, *msg++); + * return 0; + * } + * With "su USER -c EXPLOIT" run by root, exploit can make root shell + * read as input and execute arbitrary command. + * It's debatable whether we need to protect against this + * (root may hesitate to run unknown scripts interactively). + * + * Some versions of su run -c CMD in a different session: + * ioctl(TIOCSTI) works only on the controlling tty. + */ + /* Never returns */ - run_shell(opt_shell, flags & SU_OPT_l, opt_command, (const char**)argv); + run_shell(opt_shell, flags & SU_OPT_l, (const char**)argv); /* return EXIT_FAILURE; - not reached */ } |