268 lines
6.4 KiB
C
268 lines
6.4 KiB
C
/* SELinux access controls for nscd.
|
|
Copyright (C) 2004 Free Software Foundation, Inc.
|
|
This file is part of the GNU C Library.
|
|
Contributed by Matthew Rickard <mjricka@epoch.ncsc.mil>, 2004.
|
|
|
|
The GNU C Library is free software; you can redistribute it and/or
|
|
modify it under the terms of the GNU Lesser General Public
|
|
License as published by the Free Software Foundation; either
|
|
version 2.1 of the License, or (at your option) any later version.
|
|
|
|
The GNU C Library 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
|
|
Lesser General Public License for more details.
|
|
|
|
You should have received a copy of the GNU Lesser General Public
|
|
License along with the GNU C Library; if not, write to the Free
|
|
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
|
|
02111-1307 USA. */
|
|
|
|
#include <error.h>
|
|
#include <errno.h>
|
|
#include <libintl.h>
|
|
#include <pthread.h>
|
|
#include <stdarg.h>
|
|
#include <stdio.h>
|
|
#include <stdlib.h>
|
|
#include <syslog.h>
|
|
#include <selinux/av_permissions.h>
|
|
#include <selinux/avc.h>
|
|
#include <selinux/flask.h>
|
|
#include <selinux/selinux.h>
|
|
|
|
#include "dbg_log.h"
|
|
#include "selinux.h"
|
|
|
|
|
|
#ifdef HAVE_SELINUX
|
|
/* Global variable to tell if the kernel has SELinux support. */
|
|
int selinux_enabled;
|
|
|
|
/* Define mappings of access vector permissions to request types. */
|
|
static const int perms[LASTREQ] =
|
|
{
|
|
[GETPWBYNAME] = NSCD__GETPWD,
|
|
[GETPWBYUID] = NSCD__GETPWD,
|
|
[GETGRBYNAME] = NSCD__GETGRP,
|
|
[GETGRBYGID] = NSCD__GETGRP,
|
|
[GETHOSTBYNAME] = NSCD__GETHOST,
|
|
[GETHOSTBYNAMEv6] = NSCD__GETHOST,
|
|
[GETHOSTBYADDR] = NSCD__GETHOST,
|
|
[GETHOSTBYADDRv6] = NSCD__GETHOST,
|
|
[GETSTAT] = NSCD__GETSTAT,
|
|
[SHUTDOWN] = NSCD__ADMIN,
|
|
[INVALIDATE] = NSCD__ADMIN,
|
|
[GETFDPW] = NSCD__SHMEMPWD,
|
|
[GETFDGR] = NSCD__SHMEMGRP,
|
|
[GETFDHST] = NSCD__SHMEMHOST,
|
|
[GETAI] = NSCD__GETHOST,
|
|
[INITGROUPS] = NSCD__GETGRP
|
|
};
|
|
|
|
/* Store an entry ref to speed AVC decisions. */
|
|
static struct avc_entry_ref aeref;
|
|
|
|
/* Thread to listen for SELinux status changes via netlink. */
|
|
static pthread_t avc_notify_thread;
|
|
|
|
/* Prototypes for AVC callback functions. */
|
|
static void *avc_create_thread (void (*run) (void));
|
|
static void avc_stop_thread (void *thread);
|
|
static void *avc_alloc_lock (void);
|
|
static void avc_get_lock (void *lock);
|
|
static void avc_release_lock (void *lock);
|
|
static void avc_free_lock (void *lock);
|
|
|
|
/* AVC callback structures for use in avc_init. */
|
|
static const struct avc_log_callback log_cb =
|
|
{
|
|
.func_log = dbg_log,
|
|
.func_audit = NULL
|
|
};
|
|
static const struct avc_thread_callback thread_cb =
|
|
{
|
|
.func_create_thread = avc_create_thread,
|
|
.func_stop_thread = avc_stop_thread
|
|
};
|
|
static const struct avc_lock_callback lock_cb =
|
|
{
|
|
.func_alloc_lock = avc_alloc_lock,
|
|
.func_get_lock = avc_get_lock,
|
|
.func_release_lock = avc_release_lock,
|
|
.func_free_lock = avc_free_lock
|
|
};
|
|
|
|
|
|
/* Determine if we are running on an SELinux kernel. Set selinux_enabled
|
|
to the result. */
|
|
void
|
|
nscd_selinux_enabled (int *selinux_enabled)
|
|
{
|
|
*selinux_enabled = is_selinux_enabled ();
|
|
if (*selinux_enabled < 0)
|
|
{
|
|
dbg_log (_("Failed to determine if kernel supports SELinux"));
|
|
exit (EXIT_FAILURE);
|
|
}
|
|
}
|
|
|
|
|
|
/* Create thread for AVC netlink notification. */
|
|
static void *
|
|
avc_create_thread (void (*run) (void))
|
|
{
|
|
int rc;
|
|
|
|
rc =
|
|
pthread_create (&avc_notify_thread, NULL, (void *(*) (void *)) run, NULL);
|
|
if (rc != 0)
|
|
error (EXIT_FAILURE, rc, _("Failed to start AVC thread"));
|
|
|
|
return &avc_notify_thread;
|
|
}
|
|
|
|
|
|
/* Stop AVC netlink thread. */
|
|
static void
|
|
avc_stop_thread (void *thread)
|
|
{
|
|
pthread_cancel (*(pthread_t *) thread);
|
|
}
|
|
|
|
|
|
/* Allocate a new AVC lock. */
|
|
static void *
|
|
avc_alloc_lock (void)
|
|
{
|
|
pthread_mutex_t *avc_mutex;
|
|
|
|
avc_mutex = malloc (sizeof (pthread_mutex_t));
|
|
if (avc_mutex == NULL)
|
|
error (EXIT_FAILURE, errno, _("Failed to create AVC lock"));
|
|
pthread_mutex_init (avc_mutex, NULL);
|
|
|
|
return avc_mutex;
|
|
}
|
|
|
|
|
|
/* Acquire an AVC lock. */
|
|
static void
|
|
avc_get_lock (void *lock)
|
|
{
|
|
pthread_mutex_lock (lock);
|
|
}
|
|
|
|
|
|
/* Release an AVC lock. */
|
|
static void
|
|
avc_release_lock (void *lock)
|
|
{
|
|
pthread_mutex_unlock (lock);
|
|
}
|
|
|
|
|
|
/* Free an AVC lock. */
|
|
static void
|
|
avc_free_lock (void *lock)
|
|
{
|
|
pthread_mutex_destroy (lock);
|
|
free (lock);
|
|
}
|
|
|
|
|
|
/* Initialize the user space access vector cache (AVC) for NSCD along with
|
|
log/thread/lock callbacks. */
|
|
void
|
|
nscd_avc_init (void)
|
|
{
|
|
avc_entry_ref_init (&aeref);
|
|
|
|
if (avc_init ("avc", NULL, &log_cb, &thread_cb, &lock_cb) < 0)
|
|
error (EXIT_FAILURE, errno, _("Failed to start AVC"));
|
|
else
|
|
dbg_log (_("Access Vector Cache (AVC) started"));
|
|
}
|
|
|
|
|
|
/* Check the permission from the caller (via getpeercon) to nscd.
|
|
Returns 0 if access is allowed, 1 if denied, and -1 on error. */
|
|
int
|
|
nscd_request_avc_has_perm (int fd, request_type req)
|
|
{
|
|
/* Initialize to NULL so we know what to free in case of failure. */
|
|
security_context_t scon = NULL;
|
|
security_context_t tcon = NULL;
|
|
security_id_t ssid = NULL;
|
|
security_id_t tsid = NULL;
|
|
int rc = -1;
|
|
|
|
if (getpeercon (fd, &scon) < 0)
|
|
{
|
|
dbg_log (_("Error getting context of socket peer"));
|
|
goto out;
|
|
}
|
|
if (getcon (&tcon) < 0)
|
|
{
|
|
dbg_log (_("Error getting context of nscd"));
|
|
goto out;
|
|
}
|
|
if (avc_context_to_sid (scon, &ssid) < 0
|
|
|| avc_context_to_sid (tcon, &tsid) < 0)
|
|
{
|
|
dbg_log (_("Error getting sid from context"));
|
|
goto out;
|
|
}
|
|
|
|
rc = avc_has_perm (ssid, tsid, SECCLASS_NSCD, perms[req], &aeref, NULL) < 0;
|
|
|
|
out:
|
|
if (scon)
|
|
freecon (scon);
|
|
if (tcon)
|
|
freecon (tcon);
|
|
if (ssid)
|
|
sidput (ssid);
|
|
if (tsid)
|
|
sidput (tsid);
|
|
|
|
return rc;
|
|
}
|
|
|
|
|
|
/* Wrapper to get AVC statistics. */
|
|
void
|
|
nscd_avc_cache_stats (struct avc_cache_stats *cstats)
|
|
{
|
|
avc_cache_stats (cstats);
|
|
}
|
|
|
|
|
|
/* Print the AVC statistics to stdout. */
|
|
void
|
|
nscd_avc_print_stats (struct avc_cache_stats *cstats)
|
|
{
|
|
printf (_("\nSELinux AVC Statistics:\n\n"
|
|
"%15u entry lookups\n"
|
|
"%15u entry hits\n"
|
|
"%15u entry misses\n"
|
|
"%15u entry discards\n"
|
|
"%15u CAV lookups\n"
|
|
"%15u CAV hits\n"
|
|
"%15u CAV probes\n"
|
|
"%15u CAV misses\n"),
|
|
cstats->entry_lookups, cstats->entry_hits, cstats->entry_misses,
|
|
cstats->entry_discards, cstats->cav_lookups, cstats->cav_hits,
|
|
cstats->cav_probes, cstats->cav_misses);
|
|
}
|
|
|
|
|
|
/* Clean up the AVC before exiting. */
|
|
void
|
|
nscd_avc_destroy (void)
|
|
{
|
|
avc_destroy ();
|
|
}
|
|
|
|
#endif /* HAVE_SELINUX */
|