Mostly equivalent upstream commit:

commit 0699f766b10c86912b75f35bef697106b70c1cf6

Author: Carlos O'Donell <carlos@redhat.com>

Date:   Thu Apr 10 18:31:53 2014 -0400

    nscd: Make SELinux checks dynamic.

diff --git glibc-2.17-c758a686/nscd/selinux.c glibc-2.17-c758a686/nscd/selinux.c

index 0866c44..ba55b04 100644

--- glibc-2.17-c758a686/nscd/selinux.c

+++ glibc-2.17-c758a686/nscd/selinux.c

@@ -44,35 +44,31 @@

 /* Global variable to tell if the kernel has SELinux support.  */

 int selinux_enabled;

-/* Define mappings of access vector permissions to request types.  */

-static const access_vector_t perms[LASTREQ] =

+/* Define mappings of request type to AVC permission name.  */

+static const char *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,

-#ifdef NSCD__GETSERV

-  [GETSERVBYNAME] = NSCD__GETSERV,

-  [GETSERVBYPORT] = NSCD__GETSERV,

-  [GETFDSERV] = NSCD__SHMEMSERV,

-#endif

-#ifdef NSCD__GETNETGRP

-  [GETNETGRENT] = NSCD__GETNETGRP,

-  [INNETGR] = NSCD__GETNETGRP,

-  [GETFDNETGR] = NSCD__SHMEMNETGRP,

-#endif

+  [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.  */

@@ -344,7 +340,18 @@ nscd_avc_init (void)

 /* Check the permission from the caller (via getpeercon) to nscd.

-   Returns 0 if access is allowed, 1 if denied, and -1 on error.  */

+   Returns 0 if access is allowed, 1 if denied, and -1 on error.

+

+   Implementation note:

+   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 fist.

+   Instead we use symbolic mappings instead of compile time

+   constants (which selinux upstream says are going away), and 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)

 {

@@ -354,6 +361,33 @@ nscd_request_avc_has_perm (int fd, request_type req)

   security_id_t ssid = NULL;

   security_id_t tsid = NULL;

   int rc = -1;

+  security_class_t sc_nscd = 0;

+  access_vector_t perm = 0;

+  int avc_deny_unknown = 0;

+

+  /* 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.  */

+  if ((sc_nscd = string_to_security_class ("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)

     {

@@ -372,15 +406,7 @@ nscd_request_avc_has_perm (int fd, request_type req)

       goto out;

     }

-#ifndef NSCD__GETSERV

-  if (perms[req] == 0)

-    {

-      dbg_log (_("compile-time support for database policy missing"));

-      goto out;

-    }

-#endif

-

-  rc = avc_has_perm (ssid, tsid, SECCLASS_NSCD, perms[req], &aeref, NULL) < 0;

+  rc = avc_has_perm (ssid, tsid, sc_nscd, perm, &aeref, NULL) < 0;

 out:

   if (scon)