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authorUlrich Drepper <drepper@redhat.com>2004-09-17 00:04:18 +0000
committerUlrich Drepper <drepper@redhat.com>2004-09-17 00:04:18 +0000
commit74a30a5851087f40ff53f2716374c8870cd4a48a (patch)
tree2ac1d833b6114746a43a48d3113ebf8d1df4b571 /nscd
parent2fff3d93b552dbddc406c41786ecfd0a1074b564 (diff)
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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>.
Diffstat (limited to 'nscd')
-rw-r--r--nscd/Makefile8
-rw-r--r--nscd/connections.c10
-rw-r--r--nscd/nscd.c12
-rw-r--r--nscd/nscd_proto.h4
-rw-r--r--nscd/nscd_stat.c15
-rw-r--r--nscd/selinux.c266
-rw-r--r--nscd/selinux.h55
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 */