[PATCH v5 3/3] ld: Add --enable-memory-seal configure option
H.J. Lu
hjl.tools@gmail.com
Thu Jan 2 21:49:13 GMT 2025
On Fri, Jan 3, 2025 at 3:20 AM Adhemerval Zanella
<adhemerval.zanella@linaro.org> wrote:
>
> Add --enable-memory-seal linker configure option to enable memory
> sealing (GNU_PROPERTY_MEMORY_SEAL) by default.
>
> Change-Id: I4ce4ff33657f0f09b1ceb06210b6fcaa501f1799
> ---
> binutils/testsuite/lib/binutils-common.exp | 22 +++++++++++++
> ld/NEWS | 3 +-
> ld/config.in | 3 ++
> ld/configure | 38 ++++++++++++++++++----
> ld/configure.ac | 17 ++++++++++
> ld/emultempl/elf.em | 1 +
> ld/lexsup.c | 7 ++++
> ld/testsuite/config/default.exp | 8 +++++
> ld/testsuite/ld-srec/srec.exp | 4 +++
> ld/testsuite/lib/ld-lib.exp | 6 ++++
> 10 files changed, 101 insertions(+), 8 deletions(-)
>
> diff --git a/binutils/testsuite/lib/binutils-common.exp b/binutils/testsuite/lib/binutils-common.exp
> index daf12eb0fbb..72664d84bcc 100644
> --- a/binutils/testsuite/lib/binutils-common.exp
> +++ b/binutils/testsuite/lib/binutils-common.exp
> @@ -408,6 +408,25 @@ proc check_relro_support { } {
> return $relro_available_saved
> }
>
> +proc check_memory_seal_support { } {
> + global memory_seal_available_saved
> + global ld
> +
> + if {![info exists memory_seal_available_saved]} {
> + remote_file host delete nomemory_seal
> + set ld_output [remote_exec host $ld "-z nomemory-seal"]
> + if { [string first "not supported" $ld_output] >= 0
> + || [string first "unrecognized option" $ld_output] >= 0
> + || [string first "-z nomemory-seal ignored" $ld_output] >= 0
> + || [string first "cannot find nomemory-seal" $ld_output] >= 0 } {
> + set memory_seal_available_saved 0
> + } else {
> + set memory_seal_available_saved 1
> + }
> + }
> + return $memory_seal_available_saved
> +}
> +
> # Check for support of the .noinit section, used for data that is not
> # initialized at load, or during the application's initialization sequence.
> proc supports_noinit_section {} {
> @@ -1401,6 +1420,9 @@ proc run_dump_test { name {extra_options {}} } {
> if [check_relro_support] {
> set ld_extra_opt "-z norelro"
> }
> + if [check_memory_seal_support] {
> + append ld_extra_opt " -z nomemory-seal"
> + }
>
> # Add -L$srcdir/$subdir so that the linker command can use
> # linker scripts in the source directory.
> diff --git a/ld/NEWS b/ld/NEWS
> index 5d5fec4aed3..4aa5408d88f 100644
> --- a/ld/NEWS
> +++ b/ld/NEWS
> @@ -34,7 +34,8 @@ Changes in 2.43:
> * Add -plugin-save-temps to store plugin intermediate files permanently.
>
> * Add -z memory-seal/-z nomemory-seal options to ELF linker to mark the
> - object to memory sealed.
> + object to memory sealed. Also added --enable-memory-seal configure option
> + to enable the memory sealing by default.
>
> Changes in 2.42:
>
> diff --git a/ld/config.in b/ld/config.in
> index 633105a43ad..ed838463856 100644
> --- a/ld/config.in
> +++ b/ld/config.in
> @@ -60,6 +60,9 @@
> default. */
> #undef DEFAULT_LD_Z_SEPARATE_CODE
>
> +/* Define to 1 if you want to enable -z memory-seal in ELF linker by default. */
> +#undef DEFAULT_LD_Z_MEMORY_SEAL
> +
> /* Define to 1 if you want to set DT_RUNPATH instead of DT_RPATH by default.
> */
> #undef DEFAULT_NEW_DTAGS
> diff --git a/ld/configure b/ld/configure
> index 0b4197d1c4f..f34141bb238 100755
> --- a/ld/configure
> +++ b/ld/configure
> @@ -854,6 +854,7 @@ enable_textrel_check
> enable_separate_code
> enable_rosegment
> enable_mark_plt
> +enable_memory_seal
> enable_warn_execstack
> enable_error_execstack
> enable_warn_rwx_segments
> @@ -1551,6 +1552,7 @@ Optional Features:
> --enable-separate-code enable -z separate-code in ELF linker by default
> --enable-rosegment enable --rosegment in the ELF linker by default
> --enable-mark-plt enable -z mark-plt in ELF x86-64 linker by default
> + --enable-memory-seal enable -z memory-seal in ELF linker by default
> --enable-warn-execstack enable warnings when creating an executable stack
> --enable-error-execstack
> turn executable stack warnings into errors
> @@ -11686,7 +11688,7 @@ else
> lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
> lt_status=$lt_dlunknown
> cat > conftest.$ac_ext <<_LT_EOF
> -#line 11689 "configure"
> +#line 11691 "configure"
> #include "confdefs.h"
>
> #if HAVE_DLFCN_H
> @@ -11792,7 +11794,7 @@ else
> lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
> lt_status=$lt_dlunknown
> cat > conftest.$ac_ext <<_LT_EOF
> -#line 11795 "configure"
> +#line 11797 "configure"
> #include "confdefs.h"
>
> #if HAVE_DLFCN_H
> @@ -15251,7 +15253,7 @@ else
> We can't simply define LARGE_OFF_T to be 9223372036854775807,
> since some C++ compilers masquerading as C compilers
> incorrectly reject 9223372036854775807. */
> -#define LARGE_OFF_T (((off_t) 1 << 62) - 1 + ((off_t) 1 << 62))
> +#define LARGE_OFF_T ((((off_t) 1 << 31) << 31) - 1 + (((off_t) 1 << 31) << 31))
> int off_t_is_large[(LARGE_OFF_T % 2147483629 == 721
> && LARGE_OFF_T % 2147483647 == 1)
> ? 1 : -1];
> @@ -15297,7 +15299,7 @@ else
> We can't simply define LARGE_OFF_T to be 9223372036854775807,
> since some C++ compilers masquerading as C compilers
> incorrectly reject 9223372036854775807. */
> -#define LARGE_OFF_T (((off_t) 1 << 62) - 1 + ((off_t) 1 << 62))
> +#define LARGE_OFF_T ((((off_t) 1 << 31) << 31) - 1 + (((off_t) 1 << 31) << 31))
> int off_t_is_large[(LARGE_OFF_T % 2147483629 == 721
> && LARGE_OFF_T % 2147483647 == 1)
> ? 1 : -1];
> @@ -15321,7 +15323,7 @@ rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
> We can't simply define LARGE_OFF_T to be 9223372036854775807,
> since some C++ compilers masquerading as C compilers
> incorrectly reject 9223372036854775807. */
> -#define LARGE_OFF_T (((off_t) 1 << 62) - 1 + ((off_t) 1 << 62))
> +#define LARGE_OFF_T ((((off_t) 1 << 31) << 31) - 1 + (((off_t) 1 << 31) << 31))
> int off_t_is_large[(LARGE_OFF_T % 2147483629 == 721
> && LARGE_OFF_T % 2147483647 == 1)
> ? 1 : -1];
> @@ -15366,7 +15368,7 @@ else
> We can't simply define LARGE_OFF_T to be 9223372036854775807,
> since some C++ compilers masquerading as C compilers
> incorrectly reject 9223372036854775807. */
> -#define LARGE_OFF_T (((off_t) 1 << 62) - 1 + ((off_t) 1 << 62))
> +#define LARGE_OFF_T ((((off_t) 1 << 31) << 31) - 1 + (((off_t) 1 << 31) << 31))
> int off_t_is_large[(LARGE_OFF_T % 2147483629 == 721
> && LARGE_OFF_T % 2147483647 == 1)
> ? 1 : -1];
> @@ -15390,7 +15392,7 @@ rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
> We can't simply define LARGE_OFF_T to be 9223372036854775807,
> since some C++ compilers masquerading as C compilers
> incorrectly reject 9223372036854775807. */
> -#define LARGE_OFF_T (((off_t) 1 << 62) - 1 + ((off_t) 1 << 62))
> +#define LARGE_OFF_T ((((off_t) 1 << 31) << 31) - 1 + (((off_t) 1 << 31) << 31))
> int off_t_is_large[(LARGE_OFF_T % 2147483629 == 721
> && LARGE_OFF_T % 2147483647 == 1)
> ? 1 : -1];
> @@ -15709,6 +15711,17 @@ esac
> fi
>
>
> +# Decide if -z memory-seal should be enabled in ELF linker by default.
> +ac_default_ld_z_memory_seal=unset
> +# Check whether --enable-memory-seal was given.
> +if test "${enable_memory_seal+set}" = set; then :
> + enableval=$enable_memory_seal; case "${enableval}" in
> + yes) ac_default_ld_z_memory_seal=1 ;;
> + no) ac_default_ld_z_memory_seal=0 ;;
> +esac
> +fi
> +
> +
>
> # By default warn when an executable stack is created due to object files
> # requesting such, not when the user specifies -z execstack.
> @@ -18965,6 +18978,8 @@ main ()
> if (*(data + i) != *(data3 + i))
> return 14;
> close (fd);
> + free (data);
> + free (data3);
> return 0;
> }
> _ACEOF
> @@ -19444,6 +19459,15 @@ cat >>confdefs.h <<_ACEOF
> _ACEOF
>
>
> +if test "${ac_default_ld_z_memory_seal}" = unset; then
> + ac_default_ld_z_memory_seal=0
> +fi
> +
> +cat >>confdefs.h <<_ACEOF
> +#define DEFAULT_LD_Z_MEMORY_SEAL $ac_default_ld_z_memory_seal
> +_ACEOF
> +
> +
>
>
> cat >>confdefs.h <<_ACEOF
> diff --git a/ld/configure.ac b/ld/configure.ac
> index 004fa31d877..228f2ee4089 100644
> --- a/ld/configure.ac
> +++ b/ld/configure.ac
> @@ -232,6 +232,16 @@ AC_ARG_ENABLE(mark-plt,
> no) ac_default_ld_z_mark_plt=0 ;;
> esac])
>
> +# Decide if -z memory-seal should be enabled in ELF linker by default.
> +ac_default_ld_z_memory_seal=unset
> +AC_ARG_ENABLE(memory-seal,
> + AS_HELP_STRING([--enable-memory-seal],
> + [enable -z memory-seal in ELF linker by default]),
> +[case "${enableval}" in
> + yes) ac_default_ld_z_memory_seal=1 ;;
> + no) ac_default_ld_z_memory_seal=0 ;;
> +esac])
> +
>
> # By default warn when an executable stack is created due to object files
> # requesting such, not when the user specifies -z execstack.
> @@ -617,6 +627,13 @@ AC_DEFINE_UNQUOTED(DEFAULT_LD_Z_MARK_PLT,
> $ac_default_ld_z_mark_plt,
> [Define to 1 if you want to enable -z mark-plt in ELF x86-64 linker by default.])
>
> +if test "${ac_default_ld_z_memory_seal}" = unset; then
> + ac_default_ld_z_memory_seal=0
> +fi
> +AC_DEFINE_UNQUOTED(DEFAULT_LD_Z_MEMORY_SEAL,
> + $ac_default_ld_z_memory_seal,
> + [Define to 1 if you want to enable -z memory_seal in ELF linker by default.])
> +
>
> AC_DEFINE_UNQUOTED(DEFAULT_LD_WARN_EXECSTACK,
> $ac_default_ld_warn_execstack,
> diff --git a/ld/emultempl/elf.em b/ld/emultempl/elf.em
> index 9a14eae749e..d8fb034697b 100644
> --- a/ld/emultempl/elf.em
> +++ b/ld/emultempl/elf.em
> @@ -99,6 +99,7 @@ fragment <<EOF
> link_info.default_execstack = DEFAULT_LD_EXECSTACK;
> link_info.error_execstack = DEFAULT_LD_ERROR_EXECSTACK;
> link_info.warn_is_error_for_rwx_segments = DEFAULT_LD_ERROR_RWX_SEGMENTS;
> + link_info.memory_seal = DEFAULT_LD_Z_MEMORY_SEAL;
> }
>
> EOF
> diff --git a/ld/lexsup.c b/ld/lexsup.c
> index 9cf1a9a033b..5399aa45b72 100644
> --- a/ld/lexsup.c
> +++ b/ld/lexsup.c
> @@ -2265,10 +2265,17 @@ elf_shlib_list_options (FILE *file)
> fprintf (file, _("\
> -z textoff Don't treat DT_TEXTREL in output as error\n"));
> }
> +#if DEFAULT_LD_Z_MEMORY_SEAL
> + fprintf (file, _("\
> + -z memory-seal Mark object be memory sealed (default)\n"));
> + fprintf (file, _("\
> + -z nomemory-seal Don't mark oject to be memory sealed\n"));
> +#else
> fprintf (file, _("\
> -z memory-seal Mark object be memory sealed\n"));
> fprintf (file, _("\
> -z nomemory-seal Don't mark oject to be memory sealed (default)\n"));
> +#endif
> }
>
> static void
> diff --git a/ld/testsuite/config/default.exp b/ld/testsuite/config/default.exp
> index 95ff4f19e7a..f93fb30ab07 100644
> --- a/ld/testsuite/config/default.exp
> +++ b/ld/testsuite/config/default.exp
> @@ -382,6 +382,14 @@ if { ![info exists NO_DT_RELR_CC_LDFLAGS] } then {
> }
> }
>
> +if { ![info exists NO_MEMORY_SEAL_LDFLAGS] } then {
> + if { [check_memory_seal_support] } then {
> + set NO_MEMORY_SEAL_LDFLAGS "-z nomemory-seal"
> + } else {
> + set NO_MEMORY_SEAL_LDFLAGS {}
> + }
> +}
> +
> # Set LD_CLASS to "64bit" for a 64-bit *host* linker.
> if { ![info exists LD_CLASS] } then {
> set REAL_LD [findfile $base_dir/.libs/ld-new .libs/ld-new $LD [transform ld]]
> diff --git a/ld/testsuite/ld-srec/srec.exp b/ld/testsuite/ld-srec/srec.exp
> index 49ca7454d86..bec59130425 100644
> --- a/ld/testsuite/ld-srec/srec.exp
> +++ b/ld/testsuite/ld-srec/srec.exp
> @@ -226,12 +226,15 @@ proc run_srec_test { test objs } {
> global objcopy
> global sizeof_headers
> global host_triplet
> + global extra_flags
>
> # Tell the ELF linker to not do anything clever with .eh_frame,
> # not to put anything in small data, and define various symbols.
> set flags "--traditional-format -G 0 -e 0 "
> append flags [ld_link_defsyms]
>
> + append flags " $extra_flags"
> +
> # If the linker script uses SIZEOF_HEADERS, use a -Ttext argument
> # to force both the normal link and the S-record link to be put in
> # the same place. We don't always use -Ttext because it interacts
> @@ -345,6 +348,7 @@ set test2 "S-records with constructors"
> # See whether the default linker script uses SIZEOF_HEADERS.
> set exec_output [run_host_cmd "$ld" "--verbose"]
> set sizeof_headers [string match "*SIZEOF_HEADERS*" $exec_output]
> +set extra_flags " $NO_MEMORY_SEAL_LDFLAGS"
>
> # First test linking a C program. We don't require any libraries. We
> # link it normally, and objcopy to the S-record format, and then link
> diff --git a/ld/testsuite/lib/ld-lib.exp b/ld/testsuite/lib/ld-lib.exp
> index 6182d3e066a..c4653d4946b 100644
> --- a/ld/testsuite/lib/ld-lib.exp
> +++ b/ld/testsuite/lib/ld-lib.exp
> @@ -460,6 +460,9 @@ proc run_ld_link_tests { ldtests args } {
> if [check_relro_support] {
> append ld_extra_opt " -z norelro"
> }
> + if [check_memory_seal_support] {
> + append ld_extra_opt " -z nomemory-seal"
> + }
>
> foreach testitem $ldtests {
> set testname [lindex $testitem 0]
> @@ -977,6 +980,9 @@ proc run_cc_link_tests { ldtests } {
> set failed 1
> }
> } else {
> + if [check_memory_seal_support] {
> + append ldflags " -z nomemory-seal"
> + }
> if { [string match "" $STATIC_LDFLAGS] \
> && [regexp -- ".* \[-\]+static .*" " $board_cflags $board_ldflags $ldflags $objfiles "] } {
> untested $testname
> --
> 2.43.0
>
As the GNU property owner, it looks OK to me. Please apply if
there are no objections from other binutils maintainers after a few
days.
Thanks.
--
H.J.
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