Update.

2004-09-16  Ulrich Drepper  <drepper@redhat.com>

	* configure.in: Add test for required SELinux features.
	* config.make.in: Add have-selinux entry.
	* config.h.in: Add HAVE_SELINUX entry.
	* nscd/Makefile (nscd-modules): Add selinux.
	(CFLAGS-selinux.c): Add -fpie.
	Define selinux-LIBS and use in link line.
	* nscd/connections.c (handle_request): Check access SELinux permissions
	before processing request.
	* nscd/nscd.c (main): Initialize selinux_enabled and stop avc thread.
	* nscd/nscd_stat.c: Transmit and print AVC statistics.
	* nscd/selinux.c: New file.
	* nscd/selinux.h: New file.

2004-09-16  Jakub Jelinek  <jakub@redhat.com>

	* nscd/nscd_helper.c (__nscd_unmap, get_mapping): Use __munmap
	instead of munmap.

	* nscd/Makefile (CFLAGS-aicache.c): Set to -fpie.

2004-09-16  Thorsten Kukuk  <kukuk@suse.de>

	* sysdeps/posix/getaddrinfo.c (gaih_inet): Check
	__nss_not_use_nscd_hosts variable if nscd should be used or not.

2004-09-16  Ulrich Drepper  <drepper@redhat.com>

	* nscd/nscd_proto.h: Define NSS_NSCD_RETRY.
	Add __nscd_getai prototype.
	* nss/getXXbyYY_r.c: Remode definition of NSS_NSCD_RETRY.
	* nscd/nscd-client.h: Remove __nscd_getai prototype.
	* nscd/nscd_getai.c: Include nscd_proto.h.

	* elf/ldd.bash.in: Add support for SELinux environments.
	Patch by Stephen Smalley <sds@epoch.ncsc.mil>.

7 files changed, 369 insertions, 1 deletions

diff --git a/nscd/Makefile b/nscd/Makefile
index 3e6a8b5..d24bf9c 100644
--- a/nscd/Makefile
+++ b/nscd/Makefile
@@ -51,6 +51,11 @@ otherlibs += $(nssobjdir)/libnss_files.a $(resolvobjdir)/libnss_dns.a \
 	     $(resolvobjdir)/libresolv.a
 endif
 
+ifeq (yes,$(have-selinux))
+nscd-modules += selinux
+selinux-LIBS := -lselinux
+endif
+
 distribute := nscd.h nscd-client.h dbg_log.h \
 	      $(addsuffix .c, $(filter-out xmalloc, $(nscd-modules))) \
 	      nscd_nischeck.c TODO nscd.conf nscd.init nscd_proto.h \
@@ -83,6 +88,7 @@ CFLAGS-xstrdup.c = -fpie
 CFLAGS-mem.c = -fpie
 CFLAGS-nscd_setup_thread.c = -fpie
 CFLAGS-aicache.c = -fpie
+CFLAGS-selinux.c = -fpie
 
 $(objpfx)nscd: $(addprefix $(objpfx),$(nscd-modules:=.o))
 	$(LINK.o) -pie -Wl,-O1 \
@@ -91,7 +97,7 @@ $(objpfx)nscd: $(addprefix $(objpfx),$(nscd-modules:=.o))
 	  $(extra-B-$(@F:lib%.so=%).so) $(load-map-file) \
 	  $(LDFLAGS) $(LDFLAGS-$(@F)) \
 	  -L$(subst :, -L,$(rpath-link)) -Wl,-rpath-link=$(rpath-link) \
-	  -o $@ $^ $(common-objpfx)libc_nonshared.a
+	  -o $@ $^ $(selinux-LIBS) $(common-objpfx)libc_nonshared.a
 endif
 
 # This makes sure -DNOT_IN_libc is passed for all these modules.
diff --git a/nscd/connections.c b/nscd/connections.c
index fe33c76..164fdfb 100644
--- a/nscd/connections.c
+++ b/nscd/connections.c
@@ -41,6 +41,7 @@
 
 #include "nscd.h"
 #include "dbg_log.h"
+#include "selinux.h"
 
 
 /* Number of bytes of data we initially reserve for each hash table bucket.  */
@@ -592,6 +593,15 @@ cannot handle old request version %d; current version is %d"),
       return;
     }
 
+  /* Make the SELinux check before we go on to the standard checks.  We
+     need to verify that the request type is valid, since it has not
+     yet been checked at this point.  */
+  if (selinux_enabled
+      && __builtin_expect (req->type, GETPWBYNAME) >= GETPWBYNAME
+      && __builtin_expect (req->type, LASTREQ) < LASTREQ
+      && nscd_request_avc_has_perm (fd, req->type) != 0)
+    return;
+
   struct database_dyn *db = serv2db[req->type];
 
   if ((__builtin_expect (req->type, GETPWBYNAME) >= GETPWBYNAME
diff --git a/nscd/nscd.c b/nscd/nscd.c
index facea5e..b0e7a20 100644
--- a/nscd/nscd.c
+++ b/nscd/nscd.c
@@ -44,6 +44,7 @@
 
 #include "dbg_log.h"
 #include "nscd.h"
+#include "selinux.h"
 #include "../nss/nsswitch.h"
 #include <device-nrs.h>
 
@@ -126,6 +127,9 @@ main (int argc, char **argv)
   /* Set the text message domain.  */
   textdomain (PACKAGE);
 
+  /* Determine if the kernel has SELinux support.  */
+  nscd_selinux_enabled (&selinux_enabled);
+
   /* Parse and process arguments.  */
   argp_parse (&argp, argc, argv, 0, &remaining, NULL);
 
@@ -244,6 +248,10 @@ main (int argc, char **argv)
       signal (SIGTSTP, SIG_IGN);
     }
 
+  /* Start the SELinux AVC.  */
+  if (selinux_enabled)
+    nscd_avc_init ();
+
   signal (SIGINT, termination_handler);
   signal (SIGQUIT, termination_handler);
   signal (SIGTERM, termination_handler);
@@ -421,6 +429,10 @@ termination_handler (int signum)
       // XXX async OK?
       msync (dbs[cnt].head, dbs[cnt].memsize, MS_ASYNC);
 
+  /* Shutdown the SELinux AVC.  */
+  if (selinux_enabled)
+    nscd_avc_destroy ();
+
   _exit (EXIT_SUCCESS);
 }
 
diff --git a/nscd/nscd_proto.h b/nscd/nscd_proto.h
index b0ee03c..eb685a5 100644
--- a/nscd/nscd_proto.h
+++ b/nscd/nscd_proto.h
@@ -27,6 +27,10 @@
 /* Interval in which we transfer retry to contact the NSCD.  */
 #define NSS_NSCD_RETRY	100
 
+/* Type needed in the interfaces.  */
+struct nscd_ai_result;
+
+
 /* Variables for communication between NSCD handler functions and NSS.  */
 extern int __nss_not_use_nscd_passwd attribute_hidden;
 extern int __nss_not_use_nscd_group attribute_hidden;
diff --git a/nscd/nscd_stat.c b/nscd/nscd_stat.c
index ebdfeac..3e3be5b 100644
--- a/nscd/nscd_stat.c
+++ b/nscd/nscd_stat.c
@@ -29,6 +29,12 @@
 
 #include "nscd.h"
 #include "dbg_log.h"
+#include "selinux.h"
+#ifdef HAVE_SELINUX
+# include <selinux/selinux.h>
+# include <selinux/avc.h>
+#endif /* HAVE_SELINUX */
+
 
 /* We use this to make sure the receiver is the same.  */
 static const char compilation[21] = __DATE__ " " __TIME__;
@@ -71,6 +77,9 @@ struct statdata
   unsigned long int client_queued;
   int ndbs;
   struct dbstat dbs[lastdb];
+#ifdef HAVE_SELINUX
+  struct avc_cache_stats cstats;
+#endif /* HAVE_SELINUX */
 };
 
 
@@ -113,6 +122,9 @@ send_stats (int fd, struct database_dyn dbs[lastdb])
 	}
     }
 
+  if (selinux_enabled)
+    nscd_avc_cache_stats (&data.cstats);
+
   if (TEMP_FAILURE_RETRY (write (fd, &data, sizeof (data))) != sizeof (data))
     {
       char buf[256];
@@ -276,6 +288,9 @@ receive_print_stats (void)
 	      data.dbs[i].addfailed, check_file, dbnames[i]);
     }
 
+  if (selinux_enabled)
+    nscd_avc_print_stats (&data.cstats);
+
   close (fd);
 
   exit (0);
diff --git a/nscd/selinux.c b/nscd/selinux.c
new file mode 100644
index 0000000..0f975f7
--- /dev/null
+++ b/nscd/selinux.c
@@ -0,0 +1,266 @@
+/* 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
+};
+
+/* 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 */
diff --git a/nscd/selinux.h b/nscd/selinux.h
new file mode 100644
index 0000000..b9eb053
--- /dev/null
+++ b/nscd/selinux.h
@@ -0,0 +1,55 @@
+/* Header for nscd SELinux access controls.
+   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.  */
+
+#ifndef _SELINUX_H
+#define _SELINUX_H 1
+
+#include "nscd.h"
+
+#ifdef HAVE_SELINUX
+/* Global variable to tell if the kernel has SELinux support.  */
+extern int selinux_enabled;
+
+/* Define this for AVC stat usage.  */
+struct avc_cache_stats;
+
+/* Initialize the userspace AVC.  */
+extern void nscd_avc_init (void);
+/* Destroy the userspace AVC.  */
+extern void nscd_avc_destroy (void);
+/* Determine if we are running on an SELinux kernel.  */
+extern void nscd_selinux_enabled (int *selinux_enabled);
+/* Check if the client has permission for the request type.  */
+extern int nscd_request_avc_has_perm (int fd, request_type req);
+/* Initialize AVC statistic information.  */
+extern void nscd_avc_cache_stats (struct avc_cache_stats *cstats);
+/* Display statistics on AVC usage.  */
+extern void nscd_avc_print_stats (struct avc_cache_stats *cstats);
+#else
+# define selinux_enabled 0
+# define nscd_avc_init() (void) 0
+# define nscd_avc_destroy() (void) 0
+# define nscd_selinux_enabled(selinux_enabled) (void) 0
+# define nscd_request_avc_has_perm(fd, req) 0
+# define nscd_avc_cache_stats(cstats) (void) 0
+# define nscd_avc_print_stats(cstats) (void) 0
+#endif /* HAVE_SELINUX */
+
+#endif /* _SELINUX_H */