[T106][ZXW-22]7520V3SCV2.01.01.02P42U09_VEC_V0.8_AP_VEC origin source commit
Change-Id: Ic6e05d89ecd62fc34f82b23dcf306c93764aec4b
diff --git a/ap/libc/glibc/glibc-2.22/nscd/selinux.c b/ap/libc/glibc/glibc-2.22/nscd/selinux.c
new file mode 100644
index 0000000..806763f
--- /dev/null
+++ b/ap/libc/glibc/glibc-2.22/nscd/selinux.c
@@ -0,0 +1,453 @@
+/* SELinux access controls for nscd.
+ Copyright (C) 2004-2015 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, see
+ <http://www.gnu.org/licenses/>. */
+
+#include "config.h"
+#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 <unistd.h>
+#include <sys/prctl.h>
+#include <selinux/avc.h>
+#include <selinux/selinux.h>
+#ifdef HAVE_LIBAUDIT
+# include <libaudit.h>
+#endif
+
+#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 request type to AVC permission name. */
+static const char *perms[LASTREQ] =
+{
+ [GETPWBYNAME] = "getpwd",
+ [GETPWBYUID] = "getpwd",
+ [GETGRBYNAME] = "getgrp",
+ [GETGRBYGID] = "getgrp",
+ [GETHOSTBYNAME] = "gethost",
+ [GETHOSTBYNAMEv6] = "gethost",
+ [GETHOSTBYADDR] = "gethost",
+ [GETHOSTBYADDRv6] = "gethost",
+ [SHUTDOWN] = "admin",
+ [GETSTAT] = "getstat",
+ [INVALIDATE] = "admin",
+ [GETFDPW] = "shmempwd",
+ [GETFDGR] = "shmemgrp",
+ [GETFDHST] = "shmemhost",
+ [GETAI] = "gethost",
+ [INITGROUPS] = "getgrp",
+ [GETSERVBYNAME] = "getserv",
+ [GETSERVBYPORT] = "getserv",
+ [GETFDSERV] = "shmemserv",
+ [GETNETGRENT] = "getnetgrp",
+ [INNETGR] = "getnetgrp",
+ [GETFDNETGR] = "shmemnetgrp",
+};
+
+/* 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;
+
+#ifdef HAVE_LIBAUDIT
+/* Prototype for supporting the audit daemon */
+static void log_callback (const char *fmt, ...);
+#endif
+
+/* 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 =
+{
+#ifdef HAVE_LIBAUDIT
+ .func_log = log_callback,
+#else
+ .func_log = dbg_log,
+#endif
+ .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
+};
+
+#ifdef HAVE_LIBAUDIT
+/* The audit system's netlink socket descriptor */
+static int audit_fd = -1;
+
+/* When an avc denial occurs, log it to audit system */
+static void
+log_callback (const char *fmt, ...)
+{
+ if (audit_fd >= 0)
+ {
+ va_list ap;
+ va_start (ap, fmt);
+
+ char *buf;
+ int e = vasprintf (&buf, fmt, ap);
+ if (e < 0)
+ {
+ buf = alloca (BUFSIZ);
+ vsnprintf (buf, BUFSIZ, fmt, ap);
+ }
+
+ /* FIXME: need to attribute this to real user, using getuid for now */
+ audit_log_user_avc_message (audit_fd, AUDIT_USER_AVC, buf, NULL, NULL,
+ NULL, getuid ());
+
+ if (e >= 0)
+ free (buf);
+
+ va_end (ap);
+ }
+}
+
+/* Initialize the connection to the audit system */
+static void
+audit_init (void)
+{
+ audit_fd = audit_open ();
+ if (audit_fd < 0
+ /* If kernel doesn't support audit, bail out */
+ && errno != EINVAL && errno != EPROTONOSUPPORT && errno != EAFNOSUPPORT)
+ dbg_log (_("Failed opening connection to the audit subsystem: %m"));
+}
+
+
+# ifdef HAVE_LIBCAP
+static const cap_value_t new_cap_list[] =
+ { CAP_AUDIT_WRITE };
+# define nnew_cap_list (sizeof (new_cap_list) / sizeof (new_cap_list[0]))
+static const cap_value_t tmp_cap_list[] =
+ { CAP_AUDIT_WRITE, CAP_SETUID, CAP_SETGID };
+# define ntmp_cap_list (sizeof (tmp_cap_list) / sizeof (tmp_cap_list[0]))
+
+cap_t
+preserve_capabilities (void)
+{
+ if (getuid () != 0)
+ /* Not root, then we cannot preserve anything. */
+ return NULL;
+
+ if (prctl (PR_SET_KEEPCAPS, 1) == -1)
+ {
+ dbg_log (_("Failed to set keep-capabilities"));
+ do_exit (EXIT_FAILURE, errno, _("prctl(KEEPCAPS) failed"));
+ /* NOTREACHED */
+ }
+
+ cap_t tmp_caps = cap_init ();
+ cap_t new_caps = NULL;
+ if (tmp_caps != NULL)
+ new_caps = cap_init ();
+
+ if (tmp_caps == NULL || new_caps == NULL)
+ {
+ if (tmp_caps != NULL)
+ cap_free (tmp_caps);
+
+ dbg_log (_("Failed to initialize drop of capabilities"));
+ do_exit (EXIT_FAILURE, 0, _("cap_init failed"));
+ }
+
+ /* There is no reason why these should not work. */
+ cap_set_flag (new_caps, CAP_PERMITTED, nnew_cap_list,
+ (cap_value_t *) new_cap_list, CAP_SET);
+ cap_set_flag (new_caps, CAP_EFFECTIVE, nnew_cap_list,
+ (cap_value_t *) new_cap_list, CAP_SET);
+
+ cap_set_flag (tmp_caps, CAP_PERMITTED, ntmp_cap_list,
+ (cap_value_t *) tmp_cap_list, CAP_SET);
+ cap_set_flag (tmp_caps, CAP_EFFECTIVE, ntmp_cap_list,
+ (cap_value_t *) tmp_cap_list, CAP_SET);
+
+ int res = cap_set_proc (tmp_caps);
+
+ cap_free (tmp_caps);
+
+ if (__glibc_unlikely (res != 0))
+ {
+ cap_free (new_caps);
+ dbg_log (_("Failed to drop capabilities"));
+ do_exit (EXIT_FAILURE, 0, _("cap_set_proc failed"));
+ }
+
+ return new_caps;
+}
+
+void
+install_real_capabilities (cap_t new_caps)
+{
+ /* If we have no capabilities there is nothing to do here. */
+ if (new_caps == NULL)
+ return;
+
+ if (cap_set_proc (new_caps))
+ {
+ cap_free (new_caps);
+ dbg_log (_("Failed to drop capabilities"));
+ do_exit (EXIT_FAILURE, 0, _("cap_set_proc failed"));
+ /* NOTREACHED */
+ }
+
+ cap_free (new_caps);
+
+ if (prctl (PR_SET_KEEPCAPS, 0) == -1)
+ {
+ dbg_log (_("Failed to unset keep-capabilities"));
+ do_exit (EXIT_FAILURE, errno, _("prctl(KEEPCAPS) failed"));
+ /* NOTREACHED */
+ }
+}
+# endif /* HAVE_LIBCAP */
+#endif /* HAVE_LIBAUDIT */
+
+/* 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"));
+ do_exit (EXIT_FAILURE, 0, NULL);
+ }
+}
+
+
+/* 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)
+ do_exit (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)
+ do_exit (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)
+ do_exit (EXIT_FAILURE, errno, _("Failed to start AVC"));
+ else
+ dbg_log (_("Access Vector Cache (AVC) started"));
+#ifdef HAVE_LIBAUDIT
+ audit_init ();
+#endif
+}
+
+
+/* Check the permission from the caller (via getpeercon) to nscd.
+ Returns 0 if access is allowed, 1 if denied, and -1 on error.
+
+ The SELinux policy, enablement, and permission bits are all dynamic and the
+ caching done by glibc is not entirely correct. This nscd support should be
+ rewritten to use selinux_check_permission. A rewrite is risky though and
+ requires some refactoring. Currently we use symbolic mappings instead of
+ compile time constants (which SELinux upstream says are going away), and we
+ use security_deny_unknown to determine what to do if selinux-policy* doesn't
+ have a definition for the the permission or object class we are looking
+ up. */
+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;
+ security_class_t sc_nscd;
+ access_vector_t perm;
+ int avc_deny_unknown;
+
+ /* Check if SELinux denys or allows unknown object classes
+ and permissions. It is 0 if they are allowed, 1 if they
+ are not allowed and -1 on error. */
+ if ((avc_deny_unknown = security_deny_unknown ()) == -1)
+ dbg_log (_("Error querying policy for undefined object classes "
+ "or permissions."));
+
+ /* Get the security class for nscd. If this fails we will likely be
+ unable to do anything unless avc_deny_unknown is 0. */
+ sc_nscd = string_to_security_class ("nscd");
+ if (sc_nscd == 0 && avc_deny_unknown == 1)
+ dbg_log (_("Error getting security class for nscd."));
+
+ /* Convert permission to AVC bits. */
+ perm = string_to_av_perm (sc_nscd, perms[req]);
+ if (perm == 0 && avc_deny_unknown == 1)
+ dbg_log (_("Error translating permission name "
+ "\"%s\" to access vector bit."), perms[req]);
+
+ /* If the nscd security class was not found or perms were not
+ found and AVC does not deny unknown values then allow it. */
+ if ((sc_nscd == 0 || perm == 0) && avc_deny_unknown == 0)
+ return 0;
+
+ 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;
+ }
+
+ /* The SELinux API for avc_has_perm conflates access denied and error into
+ the return code -1, while nscd_request_avs_has_perm has distinct error
+ (-1) and denied (1) return codes. We map the avc_has_perm access denied or
+ error into an access denied at the nscd interface level (we do accurately
+ report error for the getpeercon, getcon, and avc_context_to_sid interfaces
+ used above). */
+ rc = avc_has_perm (ssid, tsid, sc_nscd, perm, &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);
+}
+
+#endif /* HAVE_SELINUX */