| Message ID | 20220207235127.1807294-5-hjl.tools@gmail.com |
|---|---|
| State | New |
| Headers | show |
| Series | Support DT_RELR relative relocation format | expand |
On 2022-02-07, H.J. Lu wrote: >Enable DT_RELR in glibc shared libraries and position independent >executables (PIE) automatically if linker supports -z pack-relative-relocs. > >Also add a new configuration option, --disable-default-dt-relr, to >avoid DT_RELR usage in glibc shared libraries and PIEs. >--- > INSTALL | 6 ++++++ > Makeconfig | 19 +++++++++++++++++++ > Makerules | 2 ++ > configure | 18 ++++++++++++++++++ > configure.ac | 13 +++++++++++++ > elf/Makefile | 4 +++- > manual/install.texi | 5 +++++ > 7 files changed, 66 insertions(+), 1 deletion(-) > >diff --git a/INSTALL b/INSTALL >index 63c022d6b9..4a6506f11f 100644 >--- a/INSTALL >+++ b/INSTALL >@@ -133,6 +133,12 @@ if 'CFLAGS' is specified it must enable optimization. For example: > used with the GCC option, -static-pie, which is available with GCC > 8 or above, to create static PIE. > >+'--disable-default-dt-relr' >+ Don't enable DT_RELR in glibc shared libraries and position >+ independent executables (PIE). By default, DT_RELR is enabled in >+ glibc shared libraries and position independent executables on >+ targets that support it. >+ > '--enable-cet' > '--enable-cet=permissive' > Enable Intel Control-flow Enforcement Technology (CET) support. >diff --git a/Makeconfig b/Makeconfig >index 47db08d6ae..70c0acc065 100644 >--- a/Makeconfig >+++ b/Makeconfig >@@ -358,6 +358,23 @@ else > real-static-start-installed-name = $(static-start-installed-name) > endif > >+# Linker option to enable and disable DT-RELR. >+ifeq ($(have-dt-relr),yes) >+dt-relr-ldflag = -Wl,-z,pack-relative-relocs >+no-dt-relr-ldflag = -Wl,-z,nopack-relative-relocs >+else >+dt-relr-ldflag = >+no-dt-relr-ldflag = >+endif >+ >+# Default linker option for DT-RELR. >+ifeq (yes,$(build-dt-relr-default)) >+default-rt-relr-ldflag = $(dt-relr-ldflag) >+else >+default-rt-relr-ldflag = $(no-dt-relr-ldflag) >+endif >+LDFLAGS-rtld += $(default-rt-relr-ldflag) >+ > ifeq (yesyes,$(build-shared)$(have-z-combreloc)) > combreloc-LDFLAGS = -Wl,-z,combreloc > LDFLAGS.so += $(combreloc-LDFLAGS) >@@ -419,6 +436,7 @@ link-extra-libs-tests = $(libsupport) > # Command for linking PIE programs with the C library. > ifndef +link-pie > +link-pie-before-inputs = $(if $($(@F)-no-pie),$(no-pie-ldflag),-pie) \ >+ $(if $($(@F)-no-dt-relr),$(no-dt-relr-ldflag),$(default-rt-relr-ldflag)) \ > -Wl,-O1 -nostdlib -nostartfiles \ > $(sysdep-LDFLAGS) $(LDFLAGS) $(LDFLAGS-$(@F)) \ > $(combreloc-LDFLAGS) $(relro-LDFLAGS) $(hashstyle-LDFLAGS) \ >@@ -451,6 +469,7 @@ endif > ifndef +link-static > +link-static-before-inputs = -nostdlib -nostartfiles -static \ > $(if $($(@F)-no-pie),$(no-pie-ldflag),$(static-pie-ldflag)) \ >+ $(if $($(@F)-no-dt-relr),$(no-dt-relr-ldflag),$(default-rt-relr-ldflag)) \ > $(sysdep-LDFLAGS) $(LDFLAGS) $(LDFLAGS-$(@F)) \ > $(firstword $(CRT-$(@F)) $(csu-objpfx)$(real-static-start-installed-name)) \ > $(+preinit) $(+prectorT) >diff --git a/Makerules b/Makerules >index 5de2cec6be..260c7b7253 100644 >--- a/Makerules >+++ b/Makerules >@@ -536,6 +536,7 @@ lib%.so: lib%_pic.a $(+preinit) $(+postinit) $(link-libc-deps) > define build-shlib-helper > $(LINK.o) -shared -static-libgcc -Wl,-O1 $(sysdep-LDFLAGS) \ > $(if $($(@F)-no-z-defs)$(no-z-defs),,-Wl,-z,defs) $(rtld-LDFLAGS) \ >+ $(if $($(@F)-no-dt-relr),$(no-dt-relr-ldflag),$(default-rt-relr-ldflag)) \ > $(extra-B-$(@F:lib%.so=%).so) -B$(csu-objpfx) \ > $(extra-B-$(@F:lib%.so=%).so) $(load-map-file) \ > -Wl,-soname=lib$(libprefix)$(@F:lib%.so=%).so$($(@F)-version) \ >@@ -595,6 +596,7 @@ endef > define build-module-helper > $(LINK.o) -shared -static-libgcc $(sysdep-LDFLAGS) $(rtld-LDFLAGS) \ > $(if $($(@F)-no-z-defs)$(no-z-defs),,-Wl,-z,defs) \ >+ $(if $($(@F)-no-dt-relr),$(no-dt-relr-ldflag),$(default-rt-relr-ldflag)) \ > -B$(csu-objpfx) $(load-map-file) \ > $(LDFLAGS.so) $(LDFLAGS-$(@F:%.so=%).so) \ > $(link-test-modules-rpath-link) \ >diff --git a/configure b/configure >index 9156e29fe9..ee4137a977 100755 >--- a/configure >+++ b/configure >@@ -768,6 +768,7 @@ enable_sanity_checks > enable_shared > enable_profile > enable_default_pie >+enable_default_dt_relr > enable_timezone_tools > enable_hardcoded_path_in_tests > enable_hidden_plt >@@ -1425,6 +1426,7 @@ Optional Features: > --enable-profile build profiled library [default=no] > --disable-default-pie Do not build glibc programs and the testsuite as PIE > [default=no] >+ --disable-dt-relr Do not enable DT_RELR in glibc[default=no] > --disable-timezone-tools > do not install timezone tools [default=install] > --enable-hardcoded-path-in-tests >@@ -3441,6 +3443,13 @@ else > default_pie=yes > fi > >+# Check whether --enable-default-dt-relr was given. >+if test "${enable_default_dt_relr+set}" = set; then : >+ enableval=$enable_default_dt_relr; default_dt_relr=$enableval >+else >+ default_dt_relr=yes >+fi >+ > # Check whether --enable-timezone-tools was given. > if test "${enable_timezone_tools+set}" = set; then : > enableval=$enable_timezone_tools; enable_timezone_tools=$enableval >@@ -7136,6 +7145,15 @@ fi > config_vars="$config_vars > enable-static-pie = $libc_cv_static_pie" > >+# Disable build-dt-relr-default if linker does not support it or glibc is >+# configured with --disable-default-dt-relr. >+build_dt_relr_default=$default_dt_relr >+if test "x$build_dt_relr_default" != xno; then >+ build_dt_relr_default=$libc_cv_dt_relr >+fi >+config_vars="$config_vars >+build-dt-relr-default = $build_dt_relr_default" >+ > # Set the `multidir' variable by grabbing the variable from the compiler. > # We do it once and save the result in a generated makefile. > libc_cv_multidir=`${CC-cc} $CFLAGS $CPPFLAGS -print-multi-directory` >diff --git a/configure.ac b/configure.ac >index 5c09871fee..680b036ffa 100644 >--- a/configure.ac >+++ b/configure.ac >@@ -197,6 +197,11 @@ AC_ARG_ENABLE([default-pie], > [Do not build glibc programs and the testsuite as PIE @<:@default=no@:>@]), > [default_pie=$enableval], > [default_pie=yes]) >+AC_ARG_ENABLE([default-dt-relr], >+ AS_HELP_STRING([--disable-dt-relr], >+ [Do not enable DT_RELR in glibc@<:@default=no@:>@]), >+ [default_dt_relr=$enableval], >+ [default_dt_relr=yes]) > AC_ARG_ENABLE([timezone-tools], > AS_HELP_STRING([--disable-timezone-tools], > [do not install timezone tools @<:@default=install@:>@]), >@@ -1914,6 +1919,14 @@ if test "$libc_cv_static_pie" = "yes"; then > fi > LIBC_CONFIG_VAR([enable-static-pie], [$libc_cv_static_pie]) > >+# Disable build-dt-relr-default if linker does not support it or glibc is >+# configured with --disable-default-dt-relr. >+build_dt_relr_default=$default_dt_relr >+if test "x$build_dt_relr_default" != xno; then >+ build_dt_relr_default=$libc_cv_dt_relr >+fi >+LIBC_CONFIG_VAR([build-dt-relr-default], [$build_dt_relr_default]) >+ > # Set the `multidir' variable by grabbing the variable from the compiler. > # We do it once and save the result in a generated makefile. > libc_cv_multidir=`${CC-cc} $CFLAGS $CPPFLAGS -print-multi-directory` >diff --git a/elf/Makefile b/elf/Makefile >index a6515e8a21..1727f5acc0 100644 >--- a/elf/Makefile >+++ b/elf/Makefile >@@ -1570,6 +1570,7 @@ $(objpfx)nodlopen2.out: $(objpfx)nodlopenmod2.so > > $(objpfx)filtmod1.so: $(objpfx)filtmod1.os $(objpfx)filtmod2.so > $(LINK.o) -shared -o $@ -B$(csu-objpfx) $(LDFLAGS.so) \ >+ $(default-rt-relr-ldflag) \ > -L$(subst :, -L,$(rpath-link)) \ > -Wl,-rpath-link=$(rpath-link) \ > $< -Wl,-F,$(objpfx)filtmod2.so >@@ -2376,7 +2377,7 @@ $(objpfx)tst-big-note: $(objpfx)tst-big-note-lib.so > # artificial, large note in tst-big-note-lib.o and invalidate the > # test. > $(objpfx)tst-big-note-lib.so: $(objpfx)tst-big-note-lib.o >- $(LINK.o) -shared -o $@ $(LDFLAGS.so) $< >+ $(LINK.o) -shared -o $@ $(LDFLAGS.so) $(default-rt-relr-ldflag) $< > > $(objpfx)tst-unwind-ctor: $(objpfx)tst-unwind-ctor-lib.so > >@@ -2682,6 +2683,7 @@ $(objpfx)tst-ro-dynamic: $(objpfx)tst-ro-dynamic-mod.so > $(objpfx)tst-ro-dynamic-mod.so: $(objpfx)tst-ro-dynamic-mod.os \ > tst-ro-dynamic-mod.map > $(LINK.o) -nostdlib -nostartfiles -shared -o $@ \ >+ $(default-rt-relr-ldflag) \ > -Wl,--script=tst-ro-dynamic-mod.map \ > $(objpfx)tst-ro-dynamic-mod.os > >diff --git a/manual/install.texi b/manual/install.texi >index 29c52f2927..04ea996561 100644 >--- a/manual/install.texi >+++ b/manual/install.texi >@@ -161,6 +161,11 @@ and architecture support it, static executables are built as static PIE and the > resulting glibc can be used with the GCC option, -static-pie, which is > available with GCC 8 or above, to create static PIE. > >+@item --disable-default-dt-relr >+Don't enable DT_RELR in glibc shared libraries and position independent >+executables (PIE). By default, DT_RELR is enabled in glibc shared >+libraries and position independent executables on targets that support it. >+ > @item --enable-cet > @itemx --enable-cet=permissive > Enable Intel Control-flow Enforcement Technology (CET) support. When >-- >2.34.1 > I have read an early version of this serires. This still looks good to me. Reviewed-by: Fangrui Song <maskray@google.com>
diff --git a/INSTALL b/INSTALL index 63c022d6b9..4a6506f11f 100644 --- a/INSTALL +++ b/INSTALL @@ -133,6 +133,12 @@ if 'CFLAGS' is specified it must enable optimization. For example: used with the GCC option, -static-pie, which is available with GCC 8 or above, to create static PIE. +'--disable-default-dt-relr' + Don't enable DT_RELR in glibc shared libraries and position + independent executables (PIE). By default, DT_RELR is enabled in + glibc shared libraries and position independent executables on + targets that support it. + '--enable-cet' '--enable-cet=permissive' Enable Intel Control-flow Enforcement Technology (CET) support. diff --git a/Makeconfig b/Makeconfig index 47db08d6ae..70c0acc065 100644 --- a/Makeconfig +++ b/Makeconfig @@ -358,6 +358,23 @@ else real-static-start-installed-name = $(static-start-installed-name) endif +# Linker option to enable and disable DT-RELR. +ifeq ($(have-dt-relr),yes) +dt-relr-ldflag = -Wl,-z,pack-relative-relocs +no-dt-relr-ldflag = -Wl,-z,nopack-relative-relocs +else +dt-relr-ldflag = +no-dt-relr-ldflag = +endif + +# Default linker option for DT-RELR. +ifeq (yes,$(build-dt-relr-default)) +default-rt-relr-ldflag = $(dt-relr-ldflag) +else +default-rt-relr-ldflag = $(no-dt-relr-ldflag) +endif +LDFLAGS-rtld += $(default-rt-relr-ldflag) + ifeq (yesyes,$(build-shared)$(have-z-combreloc)) combreloc-LDFLAGS = -Wl,-z,combreloc LDFLAGS.so += $(combreloc-LDFLAGS) @@ -419,6 +436,7 @@ link-extra-libs-tests = $(libsupport) # Command for linking PIE programs with the C library. ifndef +link-pie +link-pie-before-inputs = $(if $($(@F)-no-pie),$(no-pie-ldflag),-pie) \ + $(if $($(@F)-no-dt-relr),$(no-dt-relr-ldflag),$(default-rt-relr-ldflag)) \ -Wl,-O1 -nostdlib -nostartfiles \ $(sysdep-LDFLAGS) $(LDFLAGS) $(LDFLAGS-$(@F)) \ $(combreloc-LDFLAGS) $(relro-LDFLAGS) $(hashstyle-LDFLAGS) \ @@ -451,6 +469,7 @@ endif ifndef +link-static +link-static-before-inputs = -nostdlib -nostartfiles -static \ $(if $($(@F)-no-pie),$(no-pie-ldflag),$(static-pie-ldflag)) \ + $(if $($(@F)-no-dt-relr),$(no-dt-relr-ldflag),$(default-rt-relr-ldflag)) \ $(sysdep-LDFLAGS) $(LDFLAGS) $(LDFLAGS-$(@F)) \ $(firstword $(CRT-$(@F)) $(csu-objpfx)$(real-static-start-installed-name)) \ $(+preinit) $(+prectorT) diff --git a/Makerules b/Makerules index 5de2cec6be..260c7b7253 100644 --- a/Makerules +++ b/Makerules @@ -536,6 +536,7 @@ lib%.so: lib%_pic.a $(+preinit) $(+postinit) $(link-libc-deps) define build-shlib-helper $(LINK.o) -shared -static-libgcc -Wl,-O1 $(sysdep-LDFLAGS) \ $(if $($(@F)-no-z-defs)$(no-z-defs),,-Wl,-z,defs) $(rtld-LDFLAGS) \ + $(if $($(@F)-no-dt-relr),$(no-dt-relr-ldflag),$(default-rt-relr-ldflag)) \ $(extra-B-$(@F:lib%.so=%).so) -B$(csu-objpfx) \ $(extra-B-$(@F:lib%.so=%).so) $(load-map-file) \ -Wl,-soname=lib$(libprefix)$(@F:lib%.so=%).so$($(@F)-version) \ @@ -595,6 +596,7 @@ endef define build-module-helper $(LINK.o) -shared -static-libgcc $(sysdep-LDFLAGS) $(rtld-LDFLAGS) \ $(if $($(@F)-no-z-defs)$(no-z-defs),,-Wl,-z,defs) \ + $(if $($(@F)-no-dt-relr),$(no-dt-relr-ldflag),$(default-rt-relr-ldflag)) \ -B$(csu-objpfx) $(load-map-file) \ $(LDFLAGS.so) $(LDFLAGS-$(@F:%.so=%).so) \ $(link-test-modules-rpath-link) \ diff --git a/configure b/configure index 9156e29fe9..ee4137a977 100755 --- a/configure +++ b/configure @@ -768,6 +768,7 @@ enable_sanity_checks enable_shared enable_profile enable_default_pie +enable_default_dt_relr enable_timezone_tools enable_hardcoded_path_in_tests enable_hidden_plt @@ -1425,6 +1426,7 @@ Optional Features: --enable-profile build profiled library [default=no] --disable-default-pie Do not build glibc programs and the testsuite as PIE [default=no] + --disable-dt-relr Do not enable DT_RELR in glibc[default=no] --disable-timezone-tools do not install timezone tools [default=install] --enable-hardcoded-path-in-tests @@ -3441,6 +3443,13 @@ else default_pie=yes fi +# Check whether --enable-default-dt-relr was given. +if test "${enable_default_dt_relr+set}" = set; then : + enableval=$enable_default_dt_relr; default_dt_relr=$enableval +else + default_dt_relr=yes +fi + # Check whether --enable-timezone-tools was given. if test "${enable_timezone_tools+set}" = set; then : enableval=$enable_timezone_tools; enable_timezone_tools=$enableval @@ -7136,6 +7145,15 @@ fi config_vars="$config_vars enable-static-pie = $libc_cv_static_pie" +# Disable build-dt-relr-default if linker does not support it or glibc is +# configured with --disable-default-dt-relr. +build_dt_relr_default=$default_dt_relr +if test "x$build_dt_relr_default" != xno; then + build_dt_relr_default=$libc_cv_dt_relr +fi +config_vars="$config_vars +build-dt-relr-default = $build_dt_relr_default" + # Set the `multidir' variable by grabbing the variable from the compiler. # We do it once and save the result in a generated makefile. libc_cv_multidir=`${CC-cc} $CFLAGS $CPPFLAGS -print-multi-directory` diff --git a/configure.ac b/configure.ac index 5c09871fee..680b036ffa 100644 --- a/configure.ac +++ b/configure.ac @@ -197,6 +197,11 @@ AC_ARG_ENABLE([default-pie], [Do not build glibc programs and the testsuite as PIE @<:@default=no@:>@]), [default_pie=$enableval], [default_pie=yes]) +AC_ARG_ENABLE([default-dt-relr], + AS_HELP_STRING([--disable-dt-relr], + [Do not enable DT_RELR in glibc@<:@default=no@:>@]), + [default_dt_relr=$enableval], + [default_dt_relr=yes]) AC_ARG_ENABLE([timezone-tools], AS_HELP_STRING([--disable-timezone-tools], [do not install timezone tools @<:@default=install@:>@]), @@ -1914,6 +1919,14 @@ if test "$libc_cv_static_pie" = "yes"; then fi LIBC_CONFIG_VAR([enable-static-pie], [$libc_cv_static_pie]) +# Disable build-dt-relr-default if linker does not support it or glibc is +# configured with --disable-default-dt-relr. +build_dt_relr_default=$default_dt_relr +if test "x$build_dt_relr_default" != xno; then + build_dt_relr_default=$libc_cv_dt_relr +fi +LIBC_CONFIG_VAR([build-dt-relr-default], [$build_dt_relr_default]) + # Set the `multidir' variable by grabbing the variable from the compiler. # We do it once and save the result in a generated makefile. libc_cv_multidir=`${CC-cc} $CFLAGS $CPPFLAGS -print-multi-directory` diff --git a/elf/Makefile b/elf/Makefile index a6515e8a21..1727f5acc0 100644 --- a/elf/Makefile +++ b/elf/Makefile @@ -1570,6 +1570,7 @@ $(objpfx)nodlopen2.out: $(objpfx)nodlopenmod2.so $(objpfx)filtmod1.so: $(objpfx)filtmod1.os $(objpfx)filtmod2.so $(LINK.o) -shared -o $@ -B$(csu-objpfx) $(LDFLAGS.so) \ + $(default-rt-relr-ldflag) \ -L$(subst :, -L,$(rpath-link)) \ -Wl,-rpath-link=$(rpath-link) \ $< -Wl,-F,$(objpfx)filtmod2.so @@ -2376,7 +2377,7 @@ $(objpfx)tst-big-note: $(objpfx)tst-big-note-lib.so # artificial, large note in tst-big-note-lib.o and invalidate the # test. $(objpfx)tst-big-note-lib.so: $(objpfx)tst-big-note-lib.o - $(LINK.o) -shared -o $@ $(LDFLAGS.so) $< + $(LINK.o) -shared -o $@ $(LDFLAGS.so) $(default-rt-relr-ldflag) $< $(objpfx)tst-unwind-ctor: $(objpfx)tst-unwind-ctor-lib.so @@ -2682,6 +2683,7 @@ $(objpfx)tst-ro-dynamic: $(objpfx)tst-ro-dynamic-mod.so $(objpfx)tst-ro-dynamic-mod.so: $(objpfx)tst-ro-dynamic-mod.os \ tst-ro-dynamic-mod.map $(LINK.o) -nostdlib -nostartfiles -shared -o $@ \ + $(default-rt-relr-ldflag) \ -Wl,--script=tst-ro-dynamic-mod.map \ $(objpfx)tst-ro-dynamic-mod.os diff --git a/manual/install.texi b/manual/install.texi index 29c52f2927..04ea996561 100644 --- a/manual/install.texi +++ b/manual/install.texi @@ -161,6 +161,11 @@ and architecture support it, static executables are built as static PIE and the resulting glibc can be used with the GCC option, -static-pie, which is available with GCC 8 or above, to create static PIE. +@item --disable-default-dt-relr +Don't enable DT_RELR in glibc shared libraries and position independent +executables (PIE). By default, DT_RELR is enabled in glibc shared +libraries and position independent executables on targets that support it. + @item --enable-cet @itemx --enable-cet=permissive Enable Intel Control-flow Enforcement Technology (CET) support. When