ld: Add a linker configure option --enable-relro

Add a configure option --enable-relro to decide whether -z relro should
be enabled in ELF linker by default.  Default to yes for all Linux
targets, except FRV, HPPA, IA64 and MIPS, since many relro tests fail
on these targets.

	PR ld/20283
	* NEWS: Mention --enable-relro.
	* configure.ac: Add --enable-relro.
	(DEFAULT_LD_Z_RELRO): New.  Set by --enable-relro.
	* configure.tgt (ac_default_ld_z_relro): Default it to 1 for
	some Linux targets.
	* config.in: Regenerated.
	* configure: Likewise.
	* emultempl/elf32.em (gld${EMULATION_NAME}_before_parse): Set
	link_info.relro to DEFAULT_LD_Z_RELRO.
	* testsuite/config/default.exp (ld_elf_shared_opt): New.
	* testsuite/lib/ld-lib.exp (run_dump_test): Pass
	$ld_elf_shared_opt to ld for ELF targets with shared object
	support.
	(run_ld_link_tests): Likewise.

diff --git a/ld/ChangeLog b/ld/ChangeLog
index 7a2d781fc7bda5f05fcaaa02a9bb4fb6d3056f43..8c85993b60580cd06e2456403375eff07fad58da 100644 (file)
--- a/ld/ChangeLog
+++ b/ld/ChangeLog
@@ -1,3 +1,21 @@
+2016-06-22  H.J. Lu  <hongjiu.lu@intel.com>
+
+       PR ld/20283
+       * NEWS: Mention --enable-relro.
+       * configure.ac: Add --enable-relro.
+       (DEFAULT_LD_Z_RELRO): New.  Set by --enable-relro.
+       * configure.tgt (ac_default_ld_z_relro): Default it to 1 for
+       some Linux targets.
+       * config.in: Regenerated.
+       * configure: Likewise.
+       * emultempl/elf32.em (gld${EMULATION_NAME}_before_parse): Set
+       link_info.relro to DEFAULT_LD_Z_RELRO.
+       * testsuite/config/default.exp (ld_elf_shared_opt): New.
+       * testsuite/lib/ld-lib.exp (run_dump_test): Pass
+       $ld_elf_shared_opt to ld for ELF targets with shared object
+       support.
+       (run_ld_link_tests): Likewise.
+
 2016-06-21  Maciej W. Rozycki  <macro@imgtec.com>
 
        * testsuite/ld-mips-elf/mode-change-error-1a.s: Trigger an error

diff --git a/ld/NEWS b/ld/NEWS
index 228fddf71031ab6caf8e8f8b32c3117d00d7eacd..b373f7cc97deb2b8b9604ae7fa6f53a2c8913b3a 100644 (file)
--- a/ld/NEWS
+++ b/ld/NEWS
@@ -1,5 +1,9 @@
 -*- text -*-
 
+* Add a configure option --enable-relro to decide whether -z relro should
+  be enabled in ELF linker by default.  Default to yes for all Linux
+  targets except FRV, HPPA, IA64 and MIPS.
+
 * Support for -z noreloc-overflow in the x86-64 ELF linker to disable
   relocation overflow check.
 

diff --git a/ld/config.in b/ld/config.in
index 276fb776da0eec0180c58148f100a751787313b1..2c6d698b6ce14b091b21aa592a6e9d666f345188 100644 (file)
--- a/ld/config.in
+++ b/ld/config.in
@@ -10,6 +10,9 @@
 /* Define if you want compressed debug sections by default. */
 #undef DEFAULT_FLAG_COMPRESS_DEBUG
 
+/* Define to 1 if you want to enable -z relro in ELF linker by default. */
+#undef DEFAULT_LD_Z_RELRO
+
 /* Define to 1 if translation of program messages to the user's native
    language is requested. */
 #undef ENABLE_NLS

diff --git a/ld/configure b/ld/configure
index da93e0723a3dcb88a0c9a147ac3cc2657cbb5306..a469ad464a44dd64da19ae1820ece893a318aaa5 100755 (executable)
--- a/ld/configure
+++ b/ld/configure
@@ -791,6 +791,7 @@ with_sysroot
 enable_gold
 enable_got
 enable_compressed_debug_sections
+enable_relro
 enable_werror
 enable_build_warnings
 enable_nls
@@ -1449,6 +1450,7 @@ Optional Features:
                           multigot)
   --enable-compressed-debug-sections={all,ld,none}
                           compress debug sections by default]
+  --enable-relro          enable -z relro in ELF linker by default
   --enable-werror         treat compile warnings as errors
   --enable-build-warnings enable build-time compiler warnings
   --disable-nls           do not use Native Language Support
@@ -11721,7 +11723,7 @@ else
   lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
   lt_status=$lt_dlunknown
   cat > conftest.$ac_ext <<_LT_EOF
-#line 11724 "configure"
+#line 11726 "configure"
 #include "confdefs.h"
 
 #if HAVE_DLFCN_H
@@ -11827,7 +11829,7 @@ else
   lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
   lt_status=$lt_dlunknown
   cat > conftest.$ac_ext <<_LT_EOF
-#line 11830 "configure"
+#line 11832 "configure"
 #include "confdefs.h"
 
 #if HAVE_DLFCN_H
@@ -15541,6 +15543,17 @@ if test "${enable_compressed_debug_sections+set}" = set; then :
 esac
 fi
 
+# Decide if -z relro should be enabled in ELF linker by default.
+ac_default_ld_z_relro=unset
+# Provide a configure time option to override our default.
+# Check whether --enable-relro was given.
+if test "${enable_relro+set}" = set; then :
+  enableval=$enable_relro; case "${enableval}" in
+  yes)  ac_default_ld_z_relro=1 ;;
+  no)  ac_default_ld_z_relro=0 ;;
+esac
+fi
+
 
 # Set the 'development' global.
 . $srcdir/../bfd/development.sh
@@ -17147,6 +17160,15 @@ $as_echo "#define DEFAULT_FLAG_COMPRESS_DEBUG 1" >>confdefs.h
 
 fi
 
+if test "${ac_default_ld_z_relro}" = unset; then
+  ac_default_ld_z_relro=0
+fi
+
+cat >>confdefs.h <<_ACEOF
+#define DEFAULT_LD_Z_RELRO $ac_default_ld_z_relro
+_ACEOF
+
+
 
 
 

diff --git a/ld/configure.ac b/ld/configure.ac
index 65425060c02ef6029a5df6d312614d02e3bcc79c..d17281f0a0cb42ab22b5edfb33467bb9463a789d 100644 (file)
--- a/ld/configure.ac
+++ b/ld/configure.ac
@@ -155,6 +155,17 @@ AC_ARG_ENABLE(compressed_debug_sections,
   ,no, | ,none,)  ac_default_compressed_debug_sections=no ;;
 esac])dnl
 
+# Decide if -z relro should be enabled in ELF linker by default.
+ac_default_ld_z_relro=unset
+# Provide a configure time option to override our default.
+AC_ARG_ENABLE(relro,
+             AS_HELP_STRING([--enable-relro],
+             [enable -z relro in ELF linker by default]),
+[case "${enableval}" in
+  yes)  ac_default_ld_z_relro=1 ;;
+  no)  ac_default_ld_z_relro=0 ;;
+esac])dnl
+
 AM_BINUTILS_WARNINGS
 
 AM_LC_MESSAGES
@@ -376,6 +387,13 @@ if test x$ac_default_compressed_debug_sections = xyes ; then
   AC_DEFINE(DEFAULT_FLAG_COMPRESS_DEBUG, 1, [Define if you want compressed debug sections by default.])
 fi
 
+if test "${ac_default_ld_z_relro}" = unset; then
+  ac_default_ld_z_relro=0
+fi
+AC_DEFINE_UNQUOTED(DEFAULT_LD_Z_RELRO,
+  $ac_default_ld_z_relro,
+  [Define to 1 if you want to enable -z relro in ELF linker by default.])
+
 AC_SUBST(elf_list_options)
 AC_SUBST(elf_shlib_list_options)
 AC_SUBST(elf_plt_unwind_list_options)

diff --git a/ld/configure.tgt b/ld/configure.tgt
index 625194342e7bb38465956ff6a7fac6d0f170d269..a3db9091243145a57d909be1da6f1efe80d5568f 100644 (file)
--- a/ld/configure.tgt
+++ b/ld/configure.tgt
@@ -882,3 +882,28 @@ alpha*-*-*)
   ;;
 
 esac
+
+case "${target}" in
+frv-*-* | hppa*-*-* | ia64-*-* | mips*-*-*)
+  # Don't enable -z relro by default since many relro tests fail on these
+  # targets:
+  # FAIL: strip -z relro (relro1)
+  # FAIL: strip -z relro -shared (relro1)
+  # FAIL: objcopy -z relro (relro1)
+  # FAIL: objcopy -z relro -shared (relro1)
+  # FAIL: objcopy -z relro (tdata1)
+  # FAIL: objcopy -shared -z relro (tdata1)
+  # FAIL: objcopy -z relro (tdata2)
+  # FAIL: objcopy -shared -z relro (tdata2)
+  # FAIL: objcopy -z relro (tdata3)
+  # FAIL: objcopy -shared -z relro (tdata3)
+  # FAIL: objcopy -shared -z relro (tbss1)
+  # FAIL: objcopy -shared -z relro (tbss2)
+  # FAIL: objcopy -shared -z relro (tbss3)
+  ;;
+*-*-linux*)
+  if test ${ac_default_ld_z_relro} = unset; then
+    ac_default_ld_z_relro=1
+  fi
+  ;;
+esac

diff --git a/ld/emultempl/elf32.em b/ld/emultempl/elf32.em
index c2ad2022ceed804dda1caa17ca64c03f2ad08ba0..47fa549a9afef3c5d5a5538574dba5a7788fb4d6 100644 (file)
--- a/ld/emultempl/elf32.em
+++ b/ld/emultempl/elf32.em
@@ -105,6 +105,7 @@ gld${EMULATION_NAME}_before_parse (void)
   config.separate_code = `if test "x${SEPARATE_CODE}" = xyes ; then echo TRUE ; else echo FALSE ; fi`;
   `if test -n "$CALL_NOP_BYTE" ; then echo link_info.call_nop_byte = $CALL_NOP_BYTE; fi`;
   link_info.check_relocs_after_open_input = `if test "x${CHECK_RELOCS_AFTER_OPEN_INPUT}" = xyes ; then echo TRUE ; else echo FALSE ; fi`;
+  link_info.relro = DEFAULT_LD_Z_RELRO;
 }
 
 EOF

diff --git a/ld/testsuite/config/default.exp b/ld/testsuite/config/default.exp
index 8ccad111b5f930bcd4b599e34471657301a410c0..208c0d3b03d62c3419a7c60d6c6e4931c51992aa 100644 (file)
--- a/ld/testsuite/config/default.exp
+++ b/ld/testsuite/config/default.exp
@@ -76,6 +76,9 @@ if {[file exists tmpdir/libpath.exp]} {
     }
 }
 
+# Many ELF testcases expect that "-z relro" is off.
+set ld_elf_shared_opt "-z norelro"
+
 # The "make check" target in the Makefile passes in
 # "CC=$(CC_FOR_TARGET)".  But, if the user invokes runtest directly
 # (as when testing an installed linker), these flags may not be set.  

diff --git a/ld/testsuite/lib/ld-lib.exp b/ld/testsuite/lib/ld-lib.exp
index 29af846427a1a2816bffb3ad139d4227263c8be5..62f97689ac5fb5c17d6309a7cc2036a07cbe9d5d 100644 (file)
--- a/ld/testsuite/lib/ld-lib.exp
+++ b/ld/testsuite/lib/ld-lib.exp
@@ -589,6 +589,13 @@ proc run_dump_test { name {extra_options {}} } {
     global OBJDUMPFLAGS NMFLAGS ASFLAGS OBJCOPYFLAGS READELFFLAGS LDFLAGS
     global host_triplet runtests
     global env verbose
+    global ld_elf_shared_opt
+
+    if { [is_elf_format] && [check_shared_lib_support] } {
+       set ld_extra_opt "$ld_elf_shared_opt"
+    } else {
+       set ld_extra_opt ""
+    }
 
     if [string match "*/*" $name] {
        set file $name
@@ -912,7 +919,7 @@ proc run_dump_test { name {extra_options {}} } {
 
        # Add -L$srcdir/$subdir so that the linker command can use
        # linker scripts in the source directory.
-       set cmd "$LD $LDFLAGS -L$srcdir/$subdir \
+       set cmd "$LD $ld_extra_opt $LDFLAGS -L$srcdir/$subdir \
                   $opts(ld) -o $objfile $objfiles $opts(ld_after_inputfiles)"
 
         # If needed then check for, or add a -Map option.
@@ -1166,6 +1173,13 @@ proc run_ld_link_tests { ldtests } {
     global CFLAGS
     global runtests
     global exec_output
+    global ld_elf_shared_opt
+
+    if { [is_elf_format] && [check_shared_lib_support] } {
+       set ld_extra_opt "$ld_elf_shared_opt"
+    } else {
+       set ld_extra_opt ""
+    }
 
     foreach testitem $ldtests {
        set testname [lindex $testitem 0]
@@ -1228,7 +1242,7 @@ proc run_ld_link_tests { ldtests } {
            if { ![ar_simple_create $ar $ld_options $binfile "$objfiles $ld_after"] } {
                set failed 1
            }
-       } elseif { ![ld_simple_link $ld $binfile "-L$srcdir/$subdir $ld_options $objfiles $ld_after"] } {
+       } elseif { ![ld_simple_link $ld $binfile "$ld_extra_opt -L$srcdir/$subdir $ld_options $objfiles $ld_after"] } {
            set maybe_failed 1
            set ld_output "$exec_output"
        }