2006-04-26 James Antill <james.antill@redhat.com>

	    Ulrich Drepper  <drepper@redhat.com>

	* config.make.in: Add have-libcap.
	* configure.in: Check for libcap.
	* nscd/Makefile (selinux-LIBS): Add -lcap if possible.
	* nscd/connections.c (finish_drop_privileges): When libcap is available
	call preserve_capabilities and install_real_capabilities.
	* nscd/selinux.c: Define preserve_capabilities and
	install_real_capabilities.
	* nscd/selinux.h: Declare preserve_capabilities and
	install_real_capabilities.

ChangeLog

@@ -1,3 +1,16 @@
+2006-04-26  James Antill  <james.antill@redhat.com>
+	    Ulrich Drepper  <drepper@redhat.com>
+
+	* config.make.in: Add have-libcap.
+	* configure.in: Check for libcap.
+	* nscd/Makefile (selinux-LIBS): Add -lcap if possible.
+	* nscd/connections.c (finish_drop_privileges): When libcap is available
+	call preserve_capabilities and install_real_capabilities.
+	* nscd/selinux.c: Define preserve_capabilities and
+	install_real_capabilities.
+	* nscd/selinux.h: Declare preserve_capabilities and
+	install_real_capabilities.
+
 2006-04-26  Ulrich Drepper  <drepper@redhat.com>
 
 	* locale/iso-4217.def: Update.

config.make.in

@@ -61,6 +61,7 @@ have-fpie = @libc_cv_fpie@
 have-ssp = @libc_cv_ssp@
 have-selinux = @have_selinux@
 have-libaudit = @have_libaudit@
+have-libcap = @have_libcap@
 have-cc-with-libunwind = @libc_cv_cc_with_libunwind@
 fno-unit-at-a-time = @fno_unit_at_a_time@
 bind-now = @bindnow@

configure

@@ -313,7 +313,7 @@ ac_includes_default="\
 # include <unistd.h>
 #endif"
 
-ac_subst_vars='SHELL PATH_SEPARATOR PACKAGE_NAME PACKAGE_TARNAME PACKAGE_VERSION PACKAGE_STRING PACKAGE_BUGREPORT exec_prefix prefix program_transform_name bindir sbindir libexecdir datadir sysconfdir sharedstatedir localstatedir libdir includedir oldincludedir infodir mandir build_alias host_alias target_alias DEFS ECHO_C ECHO_N ECHO_T LIBS with_fp with_cvs enable_check_abi oldest_abi bindnow force_install all_warnings build build_cpu build_vendor build_os host host_cpu host_vendor host_os subdirs add_ons add_on_subdirs base_machine submachine sysnames sysdeps_add_ons INSTALL_PROGRAM INSTALL_SCRIPT INSTALL_DATA LN_S CC CFLAGS LDFLAGS CPPFLAGS ac_ct_CC OBJEXT BUILD_CC cross_compiling CPP CXX CXXFLAGS ac_ct_CXX AR OBJDUMP RANLIB ac_ct_RANLIB MIG AS LD PWD_P MAKE MSGFMT MAKEINFO SED AUTOCONF SYSINCLUDES CXX_SYSINCLUDES libc_cv_gcc_static_libgcc BASH libc_cv_have_bash2 KSH libc_cv_have_ksh AWK PERL INSTALL_INFO BISON VERSIONING libc_cv_asm_protected_directive libc_cv_cc_with_libunwind libc_cv_z_nodelete libc_cv_z_nodlopen libc_cv_z_initfirst libc_cv_z_relro libc_cv_Bgroup libc_cv_libgcc_s_suffix libc_cv_as_needed ASFLAGS_config libc_cv_z_combreloc libc_cv_z_execstack libc_cv_fpie fno_unit_at_a_time libc_cv_ssp libc_cv_have_initfini no_whole_archive exceptions LIBGD have_libaudit have_selinux EGREP sizeof_long_double libc_cv_gcc_unwind_find_fde uname_sysname uname_release uname_version old_glibc_headers libc_cv_slibdir libc_cv_localedir libc_cv_sysconfdir libc_cv_rootsbindir libc_cv_forced_unwind use_ldconfig ldd_rewrite_script elf xcoff static shared pic_default profile omitfp bounded static_nss nopic_initfini DEFINES mach_interface_list VERSION RELEASE LIBOBJS LTLIBOBJS'
+ac_subst_vars='SHELL PATH_SEPARATOR PACKAGE_NAME PACKAGE_TARNAME PACKAGE_VERSION PACKAGE_STRING PACKAGE_BUGREPORT exec_prefix prefix program_transform_name bindir sbindir libexecdir datadir sysconfdir sharedstatedir localstatedir libdir includedir oldincludedir infodir mandir build_alias host_alias target_alias DEFS ECHO_C ECHO_N ECHO_T LIBS with_fp with_cvs enable_check_abi oldest_abi bindnow force_install all_warnings build build_cpu build_vendor build_os host host_cpu host_vendor host_os subdirs add_ons add_on_subdirs base_machine submachine sysnames sysdeps_add_ons INSTALL_PROGRAM INSTALL_SCRIPT INSTALL_DATA LN_S CC CFLAGS LDFLAGS CPPFLAGS ac_ct_CC OBJEXT BUILD_CC cross_compiling CPP CXX CXXFLAGS ac_ct_CXX AR OBJDUMP RANLIB ac_ct_RANLIB MIG AS LD PWD_P MAKE MSGFMT MAKEINFO SED AUTOCONF SYSINCLUDES CXX_SYSINCLUDES libc_cv_gcc_static_libgcc BASH libc_cv_have_bash2 KSH libc_cv_have_ksh AWK PERL INSTALL_INFO BISON VERSIONING libc_cv_asm_protected_directive libc_cv_cc_with_libunwind libc_cv_z_nodelete libc_cv_z_nodlopen libc_cv_z_initfirst libc_cv_z_relro libc_cv_Bgroup libc_cv_libgcc_s_suffix libc_cv_as_needed ASFLAGS_config libc_cv_z_combreloc libc_cv_z_execstack libc_cv_fpie fno_unit_at_a_time libc_cv_ssp libc_cv_have_initfini no_whole_archive exceptions LIBGD have_libaudit have_libcap have_selinux EGREP sizeof_long_double libc_cv_gcc_unwind_find_fde uname_sysname uname_release uname_version old_glibc_headers libc_cv_slibdir libc_cv_localedir libc_cv_sysconfdir libc_cv_rootsbindir libc_cv_forced_unwind use_ldconfig ldd_rewrite_script elf xcoff static shared pic_default profile omitfp bounded static_nss nopic_initfini DEFINES mach_interface_list VERSION RELEASE LIBOBJS LTLIBOBJS'
 ac_subst_files=''
 
 # Initialize some variables set by options.
@@ -6831,6 +6831,86 @@ _ACEOF
 
   fi
 
+
+  # See if we have the libcap library
+  echo "$as_me:$LINENO: checking for cap_init in -lcap" >&5
+echo $ECHO_N "checking for cap_init in -lcap... $ECHO_C" >&6
+if test "${ac_cv_lib_cap_cap_init+set}" = set; then
+  echo $ECHO_N "(cached) $ECHO_C" >&6
+else
+  ac_check_lib_save_LIBS=$LIBS
+LIBS="-lcap  $LIBS"
+cat >conftest.$ac_ext <<_ACEOF
+/* confdefs.h.  */
+_ACEOF
+cat confdefs.h >>conftest.$ac_ext
+cat >>conftest.$ac_ext <<_ACEOF
+/* end confdefs.h.  */
+
+/* Override any gcc2 internal prototype to avoid an error.  */
+#ifdef __cplusplus
+extern "C"
+#endif
+/* We use char because int might match the return type of a gcc2
+   builtin and then its argument prototype would still apply.  */
+char cap_init ();
+int
+main ()
+{
+cap_init ();
+  ;
+  return 0;
+}
+_ACEOF
+rm -f conftest.$ac_objext conftest$ac_exeext
+if { (eval echo "$as_me:$LINENO: \"$ac_link\"") >&5
+  (eval $ac_link) 2>conftest.er1
+  ac_status=$?
+  grep -v '^ *+' conftest.er1 >conftest.err
+  rm -f conftest.er1
+  cat conftest.err >&5
+  echo "$as_me:$LINENO: \$? = $ac_status" >&5
+  (exit $ac_status); } &&
+	 { ac_try='test -z "$ac_c_werror_flag"
+			 || test ! -s conftest.err'
+  { (eval echo "$as_me:$LINENO: \"$ac_try\"") >&5
+  (eval $ac_try) 2>&5
+  ac_status=$?
+  echo "$as_me:$LINENO: \$? = $ac_status" >&5
+  (exit $ac_status); }; } &&
+	 { ac_try='test -s conftest$ac_exeext'
+  { (eval echo "$as_me:$LINENO: \"$ac_try\"") >&5
+  (eval $ac_try) 2>&5
+  ac_status=$?
+  echo "$as_me:$LINENO: \$? = $ac_status" >&5
+  (exit $ac_status); }; }; then
+  ac_cv_lib_cap_cap_init=yes
+else
+  echo "$as_me: failed program was:" >&5
+sed 's/^/| /' conftest.$ac_ext >&5
+
+ac_cv_lib_cap_cap_init=no
+fi
+rm -f conftest.err conftest.$ac_objext \
+      conftest$ac_exeext conftest.$ac_ext
+LIBS=$ac_check_lib_save_LIBS
+fi
+echo "$as_me:$LINENO: result: $ac_cv_lib_cap_cap_init" >&5
+echo "${ECHO_T}$ac_cv_lib_cap_cap_init" >&6
+if test $ac_cv_lib_cap_cap_init = yes; then
+  have_libcap=yes
+else
+  have_libcap=no
+fi
+
+  if test "x$have_libcap" = xyes; then
+
+cat >>confdefs.h <<\_ACEOF
+#define HAVE_LIBCAP 1
+_ACEOF
+
+  fi
+
 fi
 
 
@@ -8423,6 +8503,7 @@ s,@no_whole_archive@,$no_whole_archive,;t t
 s,@exceptions@,$exceptions,;t t
 s,@LIBGD@,$LIBGD,;t t
 s,@have_libaudit@,$have_libaudit,;t t
+s,@have_libcap@,$have_libcap,;t t
 s,@have_selinux@,$have_selinux,;t t
 s,@EGREP@,$EGREP,;t t
 s,@sizeof_long_double@,$sizeof_long_double,;t t

configure.in

@@ -1982,6 +1982,13 @@ if test "x$have_selinux" = xyes; then
     AC_DEFINE(HAVE_LIBAUDIT, 1, [SELinux libaudit support])
   fi
   AC_SUBST(have_libaudit)
+
+  # See if we have the libcap library
+  AC_CHECK_LIB(cap, cap_init, have_libcap=yes, have_libcap=no)
+  if test "x$have_libcap" = xyes; then
+    AC_DEFINE(HAVE_LIBCAP, 1, [SELinux libcap support])
+  fi
+  AC_SUBST(have_libcap)
 fi
 AC_SUBST(have_selinux)
 

nscd/Makefile

@@ -55,10 +55,13 @@ all-nscd-modules := $(nscd-modules) selinux
 ifeq (yes,$(have-selinux))
 ifeq (yes,$(have-libaudit))
 libaudit = -laudit
+ifeq (yes,$(have-libcap))
+libcap = -lcap
+endif
 endif
 
 nscd-modules += selinux
-selinux-LIBS := -lselinux $(libaudit)
+selinux-LIBS := -lselinux $(libaudit) $(libcap)
 
 # The configure.in check for libselinux and its headers did not use
 # $SYSINCLUDES.  The directory specified by --with-headers usually

nscd/connections.c

@@ -1859,6 +1859,11 @@ begin_drop_privileges (void)
 static void
 finish_drop_privileges (void)
 {
+#if defined HAVE_LIBAUDIT && defined HAVE_LIBCAP
+  /* We need to preserve the capabilities to connect to the audit daemon.  */
+  cap_t new_caps = preserve_capabilities ();
+#endif
+
   if (setgroups (server_ngroups, server_groups) == -1)
     {
       dbg_log (_("Failed to run nscd as user '%s'"), server_user);
@@ -1878,4 +1883,9 @@ finish_drop_privileges (void)
       perror ("setuid");
       exit (4);
     }
+
+#if defined HAVE_LIBAUDIT && defined HAVE_LIBCAP
+  /* Remove the temporary capabilities.  */
+  install_real_capabilities (new_caps);
+#endif
 }

nscd/selinux.c

@@ -28,12 +28,13 @@
 #include <stdlib.h>
 #include <syslog.h>
 #include <unistd.h>
+#include <sys/prctl.h>
 #include <selinux/av_permissions.h>
 #include <selinux/avc.h>
 #include <selinux/flask.h>
 #include <selinux/selinux.h>
 #ifdef HAVE_LIBAUDIT
-#include <libaudit.h>
+# include <libaudit.h>
 #endif
 
 #include "dbg_log.h"
@@ -149,6 +150,90 @@ audit_init (void)
       && 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"));
+      error (EXIT_FAILURE, errno, _("prctl(KEEPCAPS) failed"));
+      /* NOTREACHED */
+    }
+
+  cap_t tmp_caps = cap_init ();
+  cap_t new_caps;
+  if (tmp_caps != NULL)
+    new_caps = cap_init ();
+
+  if (tmp_caps == NULL || new_caps == NULL)
+    {
+      if (tmp_caps != NULL)
+	free_caps (tmp_caps);
+
+      dbg_log (_("Failed to initialize drop of capabilities"));
+      error (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, new_cap_list, CAP_SET);
+  cap_set_flag (new_caps, CAP_EFFECTIVE, nnew_cap_list, new_cap_list, CAP_SET);
+
+  cap_set_flag (tmp_caps, CAP_PERMITTED, ntmp_cap_list, tmp_cap_list, CAP_SET);
+  cap_set_flag (tmp_caps, CAP_EFFECTIVE, ntmp_cap_list, tmp_cap_list, CAP_SET);
+
+  int res = cap_set_proc (tmp_caps);
+
+  cap_free (tmp_caps);
+
+  if (__builtin_expect (res != 0, 0))
+    {
+      cap_free (new_caps);
+      dbg_log (_("Failed to drop capabilities\n"));
+      error (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"));
+      error (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"));
+      error (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

nscd/selinux.h

@@ -1,5 +1,5 @@
 /* Header for nscd SELinux access controls.
-   Copyright (C) 2004 Free Software Foundation, Inc.
+   Copyright (C) 2004, 2006 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
    Contributed by Matthew Rickard <mjricka@epoch.ncsc.mil>, 2004.
 
@@ -22,6 +22,9 @@
 #define _SELINUX_H 1
 
 #include "nscd.h"
+#ifdef HAVE_LIBCAP
+# include <sys/capabilities.h>
+#endif
 
 #ifdef HAVE_SELINUX
 /* Global variable to tell if the kernel has SELinux support.  */
@@ -42,6 +45,13 @@ extern int nscd_request_avc_has_perm (int fd, request_type req);
 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);
+
+# ifdef HAVE_LIBCAP
+/* Preserve capabilities to connect to connnect to the audit daemon.  */
+extern cap_t preserve_capabilities (void);
+/* Install final capabilities.  */
+extern void install_real_capabilities (cap_t new_caps);
+# endif
 #else
 # define selinux_enabled 0
 # define nscd_avc_init() (void) 0