diff options
Diffstat (limited to 'loginutils')
| -rw-r--r-- | loginutils/login.c | 2 | ||||
| -rw-r--r-- | loginutils/su.c | 33 | ||||
| -rw-r--r-- | loginutils/sulogin.c | 2 |
3 files changed, 31 insertions, 6 deletions
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); } |