diff options
| -rw-r--r-- | include/libbb.h | 2 | ||||
| -rw-r--r-- | libbb/executable.c | 2 | ||||
| -rw-r--r-- | libbb/run_shell.c | 29 | ||||
| -rw-r--r-- | loginutils/login.c | 2 | ||||
| -rw-r--r-- | loginutils/su.c | 33 | ||||
| -rw-r--r-- | loginutils/sulogin.c | 2 |
6 files changed, 45 insertions, 25 deletions
diff --git a/include/libbb.h b/include/libbb.h index 3752df9..20fc732 100644 --- a/include/libbb.h +++ b/include/libbb.h @@ -1341,7 +1341,7 @@ char *bb_simplify_abs_path_inplace(char *path) FAST_FUNC; #endif extern void bb_do_delay(int seconds) FAST_FUNC; extern void change_identity(const struct passwd *pw) FAST_FUNC; -extern void run_shell(const char *shell, int loginshell, const char *command, const char **additional_args) NORETURN FAST_FUNC; +extern void run_shell(const char *shell, int loginshell, const char **args) NORETURN FAST_FUNC; /* Returns $SHELL, getpwuid(getuid())->pw_shell, or DEFAULT_SHELL. * Note that getpwuid result might need xstrdup'ing diff --git a/libbb/executable.c b/libbb/executable.c index 05e7031..3a1d4ff 100644 --- a/libbb/executable.c +++ b/libbb/executable.c @@ -97,5 +97,5 @@ void FAST_FUNC exec_prog_or_SHELL(char **argv) if (argv[0]) { BB_EXECVP_or_die(argv); } - run_shell(getenv("SHELL"), /*login:*/ 1, NULL, NULL); + run_shell(getenv("SHELL"), /*login:*/ 1, NULL); } diff --git a/libbb/run_shell.c b/libbb/run_shell.c index 4d92c3c..b6b9360 100644 --- a/libbb/run_shell.c +++ b/libbb/run_shell.c @@ -50,19 +50,17 @@ void FAST_FUNC set_current_security_context(security_context_t sid) #endif /* Run SHELL, or DEFAULT_SHELL if SHELL is "" or NULL. - * If COMMAND is nonzero, pass it to the shell with the -c option. - * If ADDITIONAL_ARGS is nonzero, pass it to the shell as more - * arguments. */ -void FAST_FUNC run_shell(const char *shell, int loginshell, const char *command, const char **additional_args) + * If ADDITIONAL_ARGS is not NULL, pass them to the shell. + */ +void FAST_FUNC run_shell(const char *shell, int loginshell, const char **additional_args) { const char **args; - int argno; - int additional_args_cnt = 0; - for (args = additional_args; args && *args; args++) - additional_args_cnt++; + args = additional_args; + while (args && *args) + args++; - args = xmalloc(sizeof(char*) * (4 + additional_args_cnt)); + args = xmalloc(sizeof(char*) * (2 + (args - additional_args))); if (!shell || !shell[0]) shell = DEFAULT_SHELL; @@ -70,16 +68,13 @@ void FAST_FUNC run_shell(const char *shell, int loginshell, const char *command, args[0] = bb_get_last_path_component_nostrip(shell); if (loginshell) args[0] = xasprintf("-%s", args[0]); - argno = 1; - if (command) { - args[argno++] = "-c"; - args[argno++] = command; - } + args[1] = NULL; if (additional_args) { - for (; *additional_args; ++additional_args) - args[argno++] = *additional_args; + int cnt = 1; + for (;;) + if ((args[cnt++] = *additional_args++) == NULL) + break; } - args[argno] = NULL; #if ENABLE_SELINUX if (current_sid) diff --git a/loginutils/login.c b/loginutils/login.c index 94b6c45..52abc18 100644 --- a/loginutils/login.c +++ b/loginutils/login.c @@ -618,7 +618,7 @@ int login_main(int argc UNUSED_PARAM, char **argv) signal(SIGINT, SIG_DFL); /* Exec login shell with no additional parameters */ - run_shell(pw->pw_shell, 1, NULL, NULL); + run_shell(pw->pw_shell, 1, NULL); /* return EXIT_FAILURE; - not reached */ } diff --git a/loginutils/su.c b/loginutils/su.c index 3c0e8c1..24ffbde 100644 --- a/loginutils/su.c +++ b/loginutils/su.c @@ -31,10 +31,10 @@ //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" @@ -81,8 +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])) { @@ -162,8 +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 */ } diff --git a/loginutils/sulogin.c b/loginutils/sulogin.c index 6befea9..2e32e2b 100644 --- a/loginutils/sulogin.c +++ b/loginutils/sulogin.c @@ -89,5 +89,5 @@ int sulogin_main(int argc UNUSED_PARAM, char **argv) shell = pwd->pw_shell; /* Exec login shell with no additional parameters. Never returns. */ - run_shell(shell, 1, NULL, NULL); + run_shell(shell, 1, NULL); } |