diff options
Diffstat (limited to 'nscd')
| -rw-r--r-- | nscd/Makefile | 8 | ||||
| -rw-r--r-- | nscd/connections.c | 10 | ||||
| -rw-r--r-- | nscd/nscd.c | 12 | ||||
| -rw-r--r-- | nscd/nscd_proto.h | 4 | ||||
| -rw-r--r-- | nscd/nscd_stat.c | 15 | ||||
| -rw-r--r-- | nscd/selinux.c | 266 | ||||
| -rw-r--r-- | nscd/selinux.h | 55 |
7 files changed, 369 insertions, 1 deletions
diff --git a/nscd/Makefile b/nscd/Makefile index 3e6a8b5182..d24bf9c2a6 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 fe33c76bcf..164fdfbc84 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 facea5ecdb..b0e7a20947 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 b0ee03cd84..eb685a5eb0 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 ebdfeac1d4..3e3be5bc8c 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 0000000000..0f975f71f6 --- /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 0000000000..b9eb053aa0 --- /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 */ |