diff options
| -rw-r--r-- | utils/login.c | 117 |
1 files changed, 112 insertions, 5 deletions
diff --git a/utils/login.c b/utils/login.c index 46ba1191..61813228 100644 --- a/utils/login.c +++ b/utils/login.c @@ -29,6 +29,7 @@ #include <pwd.h> #include <grp.h> #include <netdb.h> +#include <time.h> #include <netinet/in.h> #include <arpa/inet.h> @@ -69,6 +70,7 @@ char *default_args[] = { "MOTD=/etc/motd", "PATH=/bin", "NOBODY=login", + "NOAUTH_TIMEOUT=300", /* seconds before unauthed sessions die. */ 0 }; /* Default values for the new environment. */ @@ -100,7 +102,6 @@ static struct argp_option options[] = {"inherit-environ", 'p', 0, 0, "Inherit the parent's environment"}, {"via", 'h', "HOST", 0, "This login is from HOST"}, {"no-passwd", 'f', 0, 0, "Don't ask for passwords"}, - {"no-utmp", 'z', 0, 0, "Don't put an entry in utmp"}, {"paranoid", 'P', 0, 0, "Don't admit that a user doesn't exist"}, {"keep", 'k', 0, 0, "Keep the old available ids, and save the old" "effective ids as available ids"}, @@ -259,6 +260,97 @@ add_entry (char **env, unsigned *env_len, char *entry) error (8, err, "Adding %s", entry); } +/* Return in OWNED whether PID has an owner, or an error. */ +static error_t +check_owned (process_t proc_server, pid_t pid, int *owned) +{ + int flags = PI_FETCH_TASKINFO; + char *waits = 0; + mach_msg_type_number_t num_waits = 0; + struct procinfo _pi, *pi = &_pi; + mach_msg_type_number_t pi_size = sizeof pi; + error_t err = + proc_getprocinfo (proc_server, pid, &flags, (procinfo_t *)&pi, &pi_size, + &waits, &num_waits); + + if (! err) + { + *owned = pi->state & PI_NOTOWNED; + if (pi != &_pi) + vm_deallocate (mach_task_self (), (vm_address_t)pi, pi_size); + } + + return err; +} + +/* Kills the login session PID with signal SIG. */ +static void +kill_login (process_t proc_server, pid_t pid, int sig) +{ + error_t err; + size_t num_pids; + do + { + pid_t _pids[num_pids = 20], *pids = _pids; + err = proc_getloginpids (proc_server, pid, &pids, &num_pids); + if (! err) + { + size_t i; + for (i = 0; i < num_pids; i++) + kill (pids[i], sig); + if (pids != _pids) + vm_deallocate (mach_task_self (), (vm_address_t)pids, num_pids); + } + } + while (!err && num_pids > 0); +} + +/* Forks a process which will kill the login session headed by PID after + TIMEOUT seconds if PID still has no owner. */ +static void +dog (time_t timeout, pid_t pid) +{ + if (fork () == 0) + { + int owned; + error_t err; + process_t proc_server = getproc (); + + sleep (timeout); + + err = check_owned (proc_server, pid, &owned); + if (err == ESRCH) + /* The process has gone away. Maybe someone is trying to play games; + just see if *any* of the remaing processes in the login session + are owned, and give up if so (this can be foiled by setuid + processes, &c, but oh well; they can be set non-executable by + nobody). */ + { + size_t num_pids = 20, i; + pid_t _pids[num_pids], *pids = _pids; + err = proc_getloginpids (proc_server, pid, &pids, &num_pids); + if (! err) + for (i = 0; i < num_pids; i++) + if (check_owned (proc_server, pids[i], &owned) == 0 && owned) + exit (0); /* Give up, luser wins. */ + /* None are owned. Kill session after emitting cryptic, yet + stupid, message. */ + fprintf (stderr, "Beware of dog.\n"); + } + else if (err) + exit (1); /* Impossible error.... XXX */ + else + /* Give normal you-forgot-to-login message. */ + fprintf (stderr, "Login timed out after %ld seconds.\n", timeout); + + /* Kill login session, trying to be nice about it. */ + kill_login (proc_server, pid, SIGHUP); + sleep (5); + kill_login (proc_server, pid, SIGKILL); + exit (0); + } +} + void main(int argc, char *argv[]) { @@ -283,7 +375,6 @@ main(int argc, char *argv[]) int no_args = 0; /* If false, put login params in the env. */ int inherit_environ = 0; /* True if we shouldn't clear our env. */ int no_passwd = 0; /* Don't bother verifying what we're doing. */ - int no_utmp = 0; /* Don't put an entry in utmp. */ int no_login = 0; /* Don't prepend `-' to the shells argv[0]. */ int paranoid = 0; /* Admit no knowledge. */ int retry = 0; /* For some failures, exec a login shell. */ @@ -310,6 +401,7 @@ main(int argc, char *argv[]) mach_port_t auth; /* The new shell's authentication. */ mach_port_t proc_server = getproc (); mach_port_t parent_auth = getauth (); + pid_t pid = getpid (), sid; /* These three functions are to do child-authenticated lookups. See <hurd/lookup.h> for an explanation. */ @@ -337,6 +429,7 @@ main(int argc, char *argv[]) int retry_argc; char **retry_argv; char *via = envz_get (args, args_len, "VIA"); + extern void _argp_unlock_xxx (); /* Secret unknown function. */ error (retry ? 0 : code, err, fmt, str); /* May exit... */ @@ -443,7 +536,6 @@ main(int argc, char *argv[]) case 'a': add_entry (&args, &args_len, arg); break; case 'A': add_entry (&args_defs, &args_defs_len, arg); break; case '0': sh_arg0 = arg; break; - case 'z': no_utmp = 1; break; case 'L': no_login = 1; break; case 'f': no_passwd = 1; break; case 'P': paranoid = 1; break; @@ -670,7 +762,8 @@ main(int argc, char *argv[]) if (eff_uids->num > 0) proc_setowner (proc_server, eff_uids->ids[0], 0); - /* XXX else clear the owner, once there's a proc call to do it. */ + else + proc_setowner (proc_server, 0, 1); /* Clear the owner. */ /* Now start constructing the exec arguments. */ bzero (ints, sizeof (*ints) * INIT_INT_MAX); @@ -853,9 +946,23 @@ main(int argc, char *argv[]) /* No more authentications to fail, so cross our fingers and add our utmp entry. */ - if (! no_utmp) + + err = proc_getsid (proc_server, pid, &sid); + if (!err && pid == sid) + /* Only add utmp entries for the session leader. */ add_utmp_entry (args, args_len, 0, !parent_has_uid (0)); + if (eff_uids->num + avail_uids->num == 0 && parent_uids->num != 0) + /* We're transiting from having some uids to having none, which means + this is probably a new login session. Unless specified otherwise, set + a timer to kill this session if it hasn't aquired any ids by then. */ + { + char *to = envz_get (args, args_len, "NOAUTH_TIMEOUT"); + time_t timeout = to ? atoi (to) : 0; + if (timeout) + dog (timeout, pid); + } + if ((eff_uids->num | eff_gids->num) && !no_login) { char *tty = ttyname (0); |