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/* AUTH PAM handling
*
* Copyright (C) 2017 Andrew Cagney
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version. See <https://www.gnu.org/licenses/gpl2.txt>.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* for more details.
*/
#include <stdlib.h>
#include <sys/wait.h> /* for WIFEXITED() et.al. */
#include <signal.h> /* for kill() and signals in general */
#include "constants.h"
#include "defs.h"
#include "log.h"
#include "pam_auth.h"
#include "pam_conv.h"
#include "event.h"
#include "state.h"
#include "connections.h"
#include "id.h"
#include "pluto_stats.h"
#include "log.h"
#include "ip_address.h"
#include "demux.h"
#include "deltatime.h"
#include "monotime.h"
#include "server_fork.h"
/* information for tracking pamauth PAM work in flight */
struct pamauth {
so_serial_t serialno;
struct pam_thread_arg ptarg;
monotime_t start_time;
pamauth_callback_t *callback;
pid_t child;
};
static void pfree_pamauth(struct pamauth *x)
{
pfree(x->ptarg.name);
pfree(x->ptarg.password);
pfree(x->ptarg.c_name);
pfree(x);
}
/*
* Abort the transaction, disconnecting it from state.
*
* Need to pass in serialno so that something sane can be logged when
* the pamauth request has already been deleted. Need to pass in
* st_callback, but only when it needs to notify an abort.
*/
void pamauth_abort(struct state *st)
{
struct pamauth *pamauth = st->st_pamauth;
if (pamauth == NULL) {
pexpect_fail(st->st_logger, HERE,
"PAM: #%lu: main-process: no process to abort (already aborted?)",
st->st_serialno);
} else {
st->st_pamauth = NULL; /* aborted */
pstats_pamauth_aborted++;
passert(pamauth->serialno == st->st_serialno);
log_state(RC_LOG, st, "PAM: #%lu: main-process: aborting authentication PAM-process for '%s'",
st->st_serialno, pamauth->ptarg.name);
/*
* Don't hold back.
*
* XXX: need to fix child so that more friendly
* SIGTERM is handled - currently the forked process
* has it blocked by libvent.
*/
kill(pamauth->child, SIGKILL);
/*
* pamauth is deleted by pamauth_pam_callback() _after_
* the process exits and the callback has been called.
*/
}
}
/*
* This is the callback from server_fork() when the process dies.
*
* On the main thread; notify the state (if it is present) of the
* pamauth result, and then release everything.
*/
static server_fork_cb pam_callback; /* type assertion */
static void pam_callback(struct state *st,
struct msg_digest *md,
int status, void *arg,
struct logger *logger)
{
struct pamauth *pamauth = arg;
pstats_pamauth_stopped++;
bool success = WIFEXITED(status) && WEXITSTATUS(status) == 0;
deltatime_buf db;
dbg("PAM: #%lu: main-process cleaning up PAM-process for user '%s' result %s time elapsed %s seconds%s",
pamauth->serialno,
pamauth->ptarg.name,
success ? "SUCCESS" : "FAILURE",
str_deltatime(monotimediff(mononow(), pamauth->start_time), &db),
(st == NULL ? " (state deleted)" :
st->st_pamauth == NULL ? " (aborted)" :
""));
/*
* Try to find the corresponding state.
*
* Since this is running on the main thread, it and
* Xauth_abort() can't get into a race.
*/
if (st != NULL) {
st->st_pamauth = NULL; /* all done */
llog(RC_LOG, logger,
"PAM: #%lu: completed for user '%s' with status %s",
pamauth->serialno, pamauth->ptarg.name,
success ? "SUCCESS" : "FAILURE");
pamauth->callback(st, md, pamauth->ptarg.name, success);
}
pfree_pamauth(pamauth);
}
/*
* Perform the authentication in the child process.
*/
static int pam_child(void *arg, struct logger *logger)
{
struct pamauth *pamauth = arg;
dbg("PAM: #%lu: PAM-process authenticating user '%s'",
pamauth->serialno,
pamauth->ptarg.name);
bool success = do_pam_authentication(&pamauth->ptarg, logger);
dbg("PAM: #%lu: PAM-process completed for user '%s' with result %s",
pamauth->serialno, pamauth->ptarg.name,
success ? "SUCCESS" : "FAILURE");
return success ? 0 : 1;
}
void auth_fork_pam_process(struct state *st,
const char *name,
const char *password,
const char *atype,
pamauth_callback_t *callback)
{
so_serial_t serialno = st->st_serialno;
/* now start the pamauth child process */
struct pamauth *pamauth = alloc_thing(struct pamauth, "pamauth arg");
pamauth->callback = callback;
pamauth->serialno = serialno;
pamauth->start_time = mononow();
/* fill in pam_thread_arg with info for the child process */
pamauth->ptarg.name = clone_str(name, "pam name");
pamauth->ptarg.password = clone_str(password, "pam password");
pamauth->ptarg.c_name = clone_str(st->st_connection->name, "pam connection name");
pamauth->ptarg.rhost = endpoint_address(&st->st_remote_endpoint);
pamauth->ptarg.st_serialno = serialno;
pamauth->ptarg.c_instance_serial = st->st_connection->instance_serial;
pamauth->ptarg.atype = atype;
dbg("PAM: #%lu: main-process starting PAM-process for authenticating user '%s'",
pamauth->serialno, pamauth->ptarg.name);
pamauth->child = server_fork("pamauth", pamauth->serialno,
pam_child, pam_callback, pamauth,
st->st_logger);
if (pamauth->child < 0) {
log_state(RC_LOG, st, "PAM: #%lu: creation of PAM-process for user '%s' failed",
pamauth->serialno, pamauth->ptarg.name);
pfree_pamauth(pamauth);
return;
}
st->st_pamauth = pamauth;
pstats_pamauth_started++;
}
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