rtld: limit self loading check to normal mode only

Commit glibc-2.14~10 disallowed rtld self loading to avoid a segfault
that used to happen when rtld was loading itself in normal mode.
Unfortunately, that commit disallowed all modes of self loading,
including those that used to work before.  This change limits the check
for self loading to normal mode only, so that instruments like ldd could
handle rtld properly.

diff --git a/ChangeLog b/ChangeLog
index ffdcfc1eb2c42848e936f774cb9f975052b0bec3..a77ef92d76a908d5bdd9374e967368997effb168 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,11 @@
+2012-09-19  Dmitry V. Levin  <ldv@altlinux.org>
+
+       [BZ #14579]
+       * elf/rtld.c (dl_main): Limit the check for self loading to normal
+       mode only.
+       * elf/tst-rtld-load-self.sh: New test.
+       * elf/Makefile: Run it.
+
 2012-09-18  Joseph Myers  <joseph@codesourcery.com>
 
        * sysdeps/wordsize-64/Makefile [$(subdir) = misc]

diff --git a/NEWS b/NEWS
index adcb741b027d95ba7413f3500de793d0f450e1e3..d9dfd2084124bc80acc0159ffa5682d5aeebca9e 100644 (file)
--- a/NEWS
+++ b/NEWS
@@ -13,8 +13,8 @@ Version 2.17
   13542, 13717, 13696, 13939, 13966, 14042, 14090, 14166, 14150, 14151,
   14154, 14157, 14166, 14173, 14195, 14237, 14252, 14283, 14298, 14303,
   14307, 14328, 14331, 14336, 14337, 14347, 14349, 14459, 14476, 14505,
-  14510, 14516, 14518, 14519, 14532, 14538, 14544, 14545, 14576, 14583,
-  14587
+  14510, 14516, 14518, 14519, 14532, 14538, 14544, 14545, 14576, 14579,
+  14583, 14587.
 
 * Support for STT_GNU_IFUNC symbols added for s390 and s390x.
   Optimized versions of memcpy, memset, and memcmp added for System z10 and

diff --git a/elf/Makefile b/elf/Makefile
index b99937624c019788c08f2f496d03736920bd6050..c844739adcdad9db6019c14ca9c68839b9a17457 100644 (file)
--- a/elf/Makefile
+++ b/elf/Makefile
@@ -434,7 +434,7 @@ generated += $(addsuffix .so,$(strip $(modules-names)))
 
 ifeq (yes,$(build-shared))
 ifeq ($(cross-compiling),no)
-tests: $(objpfx)tst-pathopt.out
+tests: $(objpfx)tst-pathopt.out $(objpfx)tst-rtld-load-self.out
 endif
 endif
 
@@ -707,6 +707,9 @@ $(objpfx)tst-pathopt.out: tst-pathopt.sh $(objpfx)tst-pathopt \
                          $(objpfx)pathoptobj.so
        $(SHELL) -e $< $(common-objpfx)
 
+$(objpfx)tst-rtld-load-self.out: tst-rtld-load-self.sh $(objpfx)ld.so
+       $(SHELL) $^ > $@
+
 $(objpfx)initfirst: $(libdl)
 $(objpfx)initfirst.out: $(objpfx)firstobj.so
 

diff --git a/elf/rtld.c b/elf/rtld.c
index fc221ace2544d5a6acc8089cd744f018b1d12796..ed0a86bb3d7f81d4c089e5b3c1b4c82254e2d740 100644 (file)
--- a/elf/rtld.c
+++ b/elf/rtld.c
@@ -1093,7 +1093,8 @@ of this helper program; chances are you did not intend to run this program.\n\
       /* Now the map for the main executable is available.  */
       main_map = GL(dl_ns)[LM_ID_BASE]._ns_loaded;
 
-      if (GL(dl_rtld_map).l_info[DT_SONAME] != NULL
+      if (__builtin_expect (mode, normal) == normal
+         && GL(dl_rtld_map).l_info[DT_SONAME] != NULL
          && main_map->l_info[DT_SONAME] != NULL
          && strcmp ((const char *) D_PTR (&GL(dl_rtld_map), l_info[DT_STRTAB])
                     + GL(dl_rtld_map).l_info[DT_SONAME]->d_un.d_val,

diff --git a/elf/tst-rtld-load-self.sh b/elf/tst-rtld-load-self.sh
new file mode 100755 (executable)
index 0000000..f4c5dea
--- /dev/null
+++ b/elf/tst-rtld-load-self.sh
@@ -0,0 +1,46 @@
+#! /bin/sh
+# Test how rtld loads itself.
+# Copyright (C) 2012 Free Software Foundation, Inc.
+# This file is part of the GNU C Library.
+#
+
+# 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/>.
+
+set -e
+
+rtld=$1
+result=0
+
+echo '# normal mode'
+$rtld $rtld 2>&1 && rc=0 || rc=$?
+echo "# exit status $rc"
+test $rc -le 127 || result=1
+
+echo '# list mode'
+$rtld --list $rtld 2>&1 && rc=0 || rc=$?
+echo "# exit status $rc"
+test $rc -eq 0 || result=1
+
+echo '# verify mode'
+$rtld --verify $rtld 2>&1 && rc=0 || rc=$?
+echo "# exit status $rc"
+test $rc -eq 2 || result=1
+
+echo '# trace mode'
+LD_TRACE_LOADED_OBJECTS=1 $rtld $rtld 2>&1 && rc=0 || rc=$?
+echo "# exit status $rc"
+test $rc -eq 0 || result=1
+
+exit $result