| Message ID | 20241028220114.3943735-1-hjl.tools@gmail.com |
|---|---|
| State | New |
| Headers | show |
| Series | [v7] elf: Handle static PIE with non-zero load address [BZ #31799] | expand |
On Mon, Oct 28, 2024 at 3:11 PM H.J. Lu <hjl.tools@gmail.com> wrote: > > For a static PIE with non-zero load address, its PT_DYNAMIC segment > entries contain the relocated values for the load address in static PIE. > Since static PIE usually doesn't have PT_PHDR segment, use p_vaddr of > the PT_LOAD segment with offset == 0 as the load address in static PIE > and adjust the entries of PT_DYNAMIC segment in static PIE by properly > setting the l_addr field for static PIE. This fixes BZ #31799. > > Signed-off-by: H.J. Lu <hjl.tools@gmail.com> > --- > configure | 74 ++++++++++++++++++++++++++++++++++++ > configure.ac | 36 ++++++++++++++++++ > elf/Makefile | 20 ++++++++++ > elf/dl-reloc-static-pie.c | 30 +++++++++++---- > elf/tst-pie-address-static.c | 19 +++++++++ > elf/tst-pie-address.c | 28 ++++++++++++++ > 6 files changed, 200 insertions(+), 7 deletions(-) > create mode 100644 elf/tst-pie-address-static.c > create mode 100644 elf/tst-pie-address.c > > diff --git a/configure b/configure > index 9c0c0dce03..9bcf62dca5 100755 > --- a/configure > +++ b/configure > @@ -8107,6 +8107,80 @@ printf "%s\n" "$libc_cv_cc_pie_default" >&6; } > config_vars="$config_vars > cc-pie-default = $libc_cv_cc_pie_default" > > +# Get Position Dependent Executable (PDE) load address to be used to > +# load static Position Independent Executable (PIE) at a known working > +# non-zero load address. This is only used by glibc tests to verify > +# that PIE and static PIE with non-zero load address work correctly. > +{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking PDE load address" >&5 > +printf %s "checking PDE load address... " >&6; } > +if test ${libc_cv_pde_load_address+y} > +then : > + printf %s "(cached) " >&6 > +else case e in #( > + e) cat > conftest.S <<EOF > +.globl _start > +_start: > +.globl __start > +__start: > +EOF > +if test $libc_cv_cc_pie_default = yes; then > + pde_ld_flags="-no-pie" > +fi > +if ${CC-cc} $pde_ld_flags $CFLAGS $CPPFLAGS $LDFLAGS \ > + -nostartfiles -nostdlib $no_ssp \ > + -o conftest conftest.S 1>&5 2>&5; then > + # Get the load address of the first PT_LOAD segment. > + libc_cv_pde_load_address=$(LC_ALL=C $READELF -Wl conftest \ > + | $AWK '/LOAD/ { print $3; exit 0; }') > +else > + as_fn_error $? "${CC-cc} can not create PDE" "$LINENO" 5 > +fi > +rm -f conftest* ;; > +esac > +fi > +{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $libc_cv_pde_load_address" >&5 > +printf "%s\n" "$libc_cv_pde_load_address" >&6; } > +config_vars="$config_vars > +pde-load-address = $libc_cv_pde_load_address" > + > +# Get the linker command-line option to load executable at a non-zero > +# load address. This is only used by glibc tests to verify that PIE and > +# static PIE with non-zero load address work correctly. > +{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for linker that supports -Ttext-segment=$libc_cv_pde_load_address" >&5 > +printf %s "checking for linker that supports -Ttext-segment=$libc_cv_pde_load_address... " >&6; } > +libc_linker_feature=no > +cat > conftest.c <<EOF > +int _start (void) { return 42; } > +EOF > +if { ac_try='${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS $no_ssp > + -Wl,-Ttext-segment=$libc_cv_pde_load_address -nostdlib -nostartfiles > + -fPIC -shared -o conftest.so conftest.c > + 1>&5' > + { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5 > + (eval $ac_try) 2>&5 > + ac_status=$? > + printf "%s\n" "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5 > + test $ac_status = 0; }; } > +then > + if ${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS $no_ssp -Wl,-Ttext-segment=$libc_cv_pde_load_address -nostdlib \ > + -nostartfiles -fPIC -shared -o conftest.so conftest.c 2>&1 \ > + | grep "warning: -Ttext-segment=$libc_cv_pde_load_address ignored" > /dev/null 2>&1; then > + true > + else > + libc_linker_feature=yes > + fi > +fi > +rm -f conftest* > +if test $libc_linker_feature = yes; then > + libc_cv_load_address_ldflag=-Wl,-Ttext-segment > +else > + libc_cv_load_address_ldflag= > +fi > +{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $libc_linker_feature" >&5 > +printf "%s\n" "$libc_linker_feature" >&6; } > +config_vars="$config_vars > +load-address-ldflag = $libc_cv_load_address_ldflag" > + > { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking if we can build programs as PIE" >&5 > printf %s "checking if we can build programs as PIE... " >&6; } > cat confdefs.h - <<_ACEOF >conftest.$ac_ext > diff --git a/configure.ac b/configure.ac > index d5a00461ff..895bd5267d 100644 > --- a/configure.ac > +++ b/configure.ac > @@ -1763,6 +1763,42 @@ fi > rm -f conftest.*]) > LIBC_CONFIG_VAR([cc-pie-default], [$libc_cv_cc_pie_default]) > > +# Get Position Dependent Executable (PDE) load address to be used to > +# load static Position Independent Executable (PIE) at a known working > +# non-zero load address. This is only used by glibc tests to verify > +# that PIE and static PIE with non-zero load address work correctly. > +AC_CACHE_CHECK([PDE load address], > + libc_cv_pde_load_address, [dnl > +cat > conftest.S <<EOF > +.globl _start > +_start: > +.globl __start > +__start: > +EOF > +if test $libc_cv_cc_pie_default = yes; then > + pde_ld_flags="-no-pie" > +fi > +if ${CC-cc} $pde_ld_flags $CFLAGS $CPPFLAGS $LDFLAGS \ > + -nostartfiles -nostdlib $no_ssp \ > + -o conftest conftest.S 1>&AS_MESSAGE_LOG_FD 2>&AS_MESSAGE_LOG_FD; then > + # Get the load address of the first PT_LOAD segment. > + libc_cv_pde_load_address=$(LC_ALL=C $READELF -Wl conftest \ > + | $AWK '/LOAD/ { print $3; exit 0; }') > +else > + AC_MSG_ERROR([${CC-cc} can not create PDE]) > +fi > +rm -f conftest*]) > +LIBC_CONFIG_VAR([pde-load-address], [$libc_cv_pde_load_address]) > + > +# Get the linker command-line option to load executable at a non-zero > +# load address. This is only used by glibc tests to verify that PIE and > +# static PIE with non-zero load address work correctly. > +LIBC_LINKER_FEATURE([-Ttext-segment=$libc_cv_pde_load_address], > + [-Wl,-Ttext-segment=$libc_cv_pde_load_address], > + [libc_cv_load_address_ldflag=-Wl,-Ttext-segment], > + [libc_cv_load_address_ldflag=]) > +LIBC_CONFIG_VAR([load-address-ldflag], [$libc_cv_load_address_ldflag]) > + > AC_MSG_CHECKING(if we can build programs as PIE) > AC_COMPILE_IFELSE([AC_LANG_SOURCE([[#ifdef PIE_UNSUPPORTED > # error PIE is not supported > diff --git a/elf/Makefile b/elf/Makefile > index 9cfe738919..4eaca7af67 100644 > --- a/elf/Makefile > +++ b/elf/Makefile > @@ -1091,6 +1091,25 @@ tests-pie += \ > tst-pie1 \ > tst-pie2 \ > # tests-pie > +ifneq (,$(load-address-ldflag)) > +tests += \ > + tst-pie-address \ > + # tests > +tests-pie += \ > + tst-pie-address \ > + # tests-pie > +LDFLAGS-tst-pie-address += $(load-address-ldflag)=$(pde-load-address) > +ifeq (yes,$(enable-static-pie)) > +tests += \ > + tst-pie-address-static \ > + # tests > +tests-static += \ > + tst-pie-address-static \ > + # tests-static > +LDFLAGS-tst-pie-address-static += \ > + $(load-address-ldflag)=$(pde-load-address) > +endif > +endif > ifeq (yes,$(have-protected-data)) > tests += vismain > tests-pie += vismain > @@ -1937,6 +1956,7 @@ $(objpfx)tst-array5-static-cmp.out: tst-array5-static.exp \ > > CFLAGS-tst-pie1.c += $(pie-ccflag) > CFLAGS-tst-pie2.c += $(pie-ccflag) > +CFLAGS-tst-pie-address.c += $(pie-ccflag) > > $(objpfx)tst-piemod1.so: $(libsupport) > $(objpfx)tst-pie1: $(objpfx)tst-piemod1.so > diff --git a/elf/dl-reloc-static-pie.c b/elf/dl-reloc-static-pie.c > index 10c23d0bf0..bfee89dfc3 100644 > --- a/elf/dl-reloc-static-pie.c > +++ b/elf/dl-reloc-static-pie.c > @@ -37,21 +37,37 @@ _dl_relocate_static_pie (void) > { > struct link_map *main_map = _dl_get_dl_main_map (); > > - /* Figure out the run-time load address of static PIE. */ > - main_map->l_addr = elf_machine_load_address (); > - > - /* Read our own dynamic section and fill in the info array. */ > - main_map->l_ld = ((void *) main_map->l_addr + elf_machine_dynamic ()); > - > + /* NB: elf_machine_load_address () returns the run-time load address > + of static PIE. The l_addr field contains the difference between the > + link-time load address in the ELF file and the run-time load address > + in memory. We must subtract the link-time load address of static PIE, > + which can be non-zero, when computing the l_addr field. Since static > + PIE usually doesn't have PT_PHDR segment, use p_vaddr of the PT_LOAD > + segment with offset == 0 as the load address of static PIE. */ > + ElfW(Addr) file_p_vaddr = 0; > const ElfW(Phdr) *ph, *phdr = GL(dl_phdr); > size_t phnum = GL(dl_phnum); > for (ph = phdr; ph < &phdr[phnum]; ++ph) > - if (ph->p_type == PT_DYNAMIC) > + switch (ph->p_type) > { > + case PT_LOAD: > + if (ph->p_offset == 0) > + file_p_vaddr = ph->p_vaddr; > + break; > + case PT_DYNAMIC: > main_map->l_ld_readonly = (ph->p_flags & PF_W) == 0; > break; > + default: > + break; > } > > + /* Figure out the run-time load address of static PIE. */ > + ElfW(Addr) l_addr = elf_machine_load_address (); > + main_map->l_addr = l_addr - file_p_vaddr; > + > + /* Read our own dynamic section and fill in the info array. */ > + main_map->l_ld = ((void *) l_addr + elf_machine_dynamic ()); > + > elf_get_dynamic_info (main_map, false, true); > > # ifdef ELF_MACHINE_BEFORE_RTLD_RELOC > diff --git a/elf/tst-pie-address-static.c b/elf/tst-pie-address-static.c > new file mode 100644 > index 0000000000..be2831e9d6 > --- /dev/null > +++ b/elf/tst-pie-address-static.c > @@ -0,0 +1,19 @@ > +/* Test static PIE with non-zero load address. > + Copyright (C) 2024 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 > + <https://www.gnu.org/licenses/>. */ > + > +#include "tst-pie-address.c" > diff --git a/elf/tst-pie-address.c b/elf/tst-pie-address.c > new file mode 100644 > index 0000000000..aa1ca0a9fd > --- /dev/null > +++ b/elf/tst-pie-address.c > @@ -0,0 +1,28 @@ > +/* Test PIE with non-zero load address. > + Copyright (C) 2024 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 > + <https://www.gnu.org/licenses/>. */ > + > +#include <stdio.h> > + > +static int > +do_test (void) > +{ > + printf ("Hello\n"); > + return 0; > +} > + > +#include <support/test-driver.c> > -- > 2.47.0 > LGTM. Think Carlos was also going to take a look at this (from monday review minutes), so please wait for Carlos to take a look too before pushing.
On Tue, Oct 29, 2024 at 1:33 PM Noah Goldstein <goldstein.w.n@gmail.com> wrote: > > On Mon, Oct 28, 2024 at 3:11 PM H.J. Lu <hjl.tools@gmail.com> wrote: > > > > For a static PIE with non-zero load address, its PT_DYNAMIC segment > > entries contain the relocated values for the load address in static PIE. > > Since static PIE usually doesn't have PT_PHDR segment, use p_vaddr of > > the PT_LOAD segment with offset == 0 as the load address in static PIE > > and adjust the entries of PT_DYNAMIC segment in static PIE by properly > > setting the l_addr field for static PIE. This fixes BZ #31799. > > > > Signed-off-by: H.J. Lu <hjl.tools@gmail.com> > > --- > > configure | 74 ++++++++++++++++++++++++++++++++++++ > > configure.ac | 36 ++++++++++++++++++ > > elf/Makefile | 20 ++++++++++ > > elf/dl-reloc-static-pie.c | 30 +++++++++++---- > > elf/tst-pie-address-static.c | 19 +++++++++ > > elf/tst-pie-address.c | 28 ++++++++++++++ > > 6 files changed, 200 insertions(+), 7 deletions(-) > > create mode 100644 elf/tst-pie-address-static.c > > create mode 100644 elf/tst-pie-address.c > > > > diff --git a/configure b/configure > > index 9c0c0dce03..9bcf62dca5 100755 > > --- a/configure > > +++ b/configure > > @@ -8107,6 +8107,80 @@ printf "%s\n" "$libc_cv_cc_pie_default" >&6; } > > config_vars="$config_vars > > cc-pie-default = $libc_cv_cc_pie_default" > > > > +# Get Position Dependent Executable (PDE) load address to be used to > > +# load static Position Independent Executable (PIE) at a known working > > +# non-zero load address. This is only used by glibc tests to verify > > +# that PIE and static PIE with non-zero load address work correctly. > > +{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking PDE load address" >&5 > > +printf %s "checking PDE load address... " >&6; } > > +if test ${libc_cv_pde_load_address+y} > > +then : > > + printf %s "(cached) " >&6 > > +else case e in #( > > + e) cat > conftest.S <<EOF > > +.globl _start > > +_start: > > +.globl __start > > +__start: > > +EOF > > +if test $libc_cv_cc_pie_default = yes; then > > + pde_ld_flags="-no-pie" > > +fi > > +if ${CC-cc} $pde_ld_flags $CFLAGS $CPPFLAGS $LDFLAGS \ > > + -nostartfiles -nostdlib $no_ssp \ > > + -o conftest conftest.S 1>&5 2>&5; then > > + # Get the load address of the first PT_LOAD segment. > > + libc_cv_pde_load_address=$(LC_ALL=C $READELF -Wl conftest \ > > + | $AWK '/LOAD/ { print $3; exit 0; }') > > +else > > + as_fn_error $? "${CC-cc} can not create PDE" "$LINENO" 5 > > +fi > > +rm -f conftest* ;; > > +esac > > +fi > > +{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $libc_cv_pde_load_address" >&5 > > +printf "%s\n" "$libc_cv_pde_load_address" >&6; } > > +config_vars="$config_vars > > +pde-load-address = $libc_cv_pde_load_address" > > + > > +# Get the linker command-line option to load executable at a non-zero > > +# load address. This is only used by glibc tests to verify that PIE and > > +# static PIE with non-zero load address work correctly. > > +{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for linker that supports -Ttext-segment=$libc_cv_pde_load_address" >&5 > > +printf %s "checking for linker that supports -Ttext-segment=$libc_cv_pde_load_address... " >&6; } > > +libc_linker_feature=no > > +cat > conftest.c <<EOF > > +int _start (void) { return 42; } > > +EOF > > +if { ac_try='${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS $no_ssp > > + -Wl,-Ttext-segment=$libc_cv_pde_load_address -nostdlib -nostartfiles > > + -fPIC -shared -o conftest.so conftest.c > > + 1>&5' > > + { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5 > > + (eval $ac_try) 2>&5 > > + ac_status=$? > > + printf "%s\n" "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5 > > + test $ac_status = 0; }; } > > +then > > + if ${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS $no_ssp -Wl,-Ttext-segment=$libc_cv_pde_load_address -nostdlib \ > > + -nostartfiles -fPIC -shared -o conftest.so conftest.c 2>&1 \ > > + | grep "warning: -Ttext-segment=$libc_cv_pde_load_address ignored" > /dev/null 2>&1; then > > + true > > + else > > + libc_linker_feature=yes > > + fi > > +fi > > +rm -f conftest* > > +if test $libc_linker_feature = yes; then > > + libc_cv_load_address_ldflag=-Wl,-Ttext-segment > > +else > > + libc_cv_load_address_ldflag= > > +fi > > +{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $libc_linker_feature" >&5 > > +printf "%s\n" "$libc_linker_feature" >&6; } > > +config_vars="$config_vars > > +load-address-ldflag = $libc_cv_load_address_ldflag" > > + > > { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking if we can build programs as PIE" >&5 > > printf %s "checking if we can build programs as PIE... " >&6; } > > cat confdefs.h - <<_ACEOF >conftest.$ac_ext > > diff --git a/configure.ac b/configure.ac > > index d5a00461ff..895bd5267d 100644 > > --- a/configure.ac > > +++ b/configure.ac > > @@ -1763,6 +1763,42 @@ fi > > rm -f conftest.*]) > > LIBC_CONFIG_VAR([cc-pie-default], [$libc_cv_cc_pie_default]) > > > > +# Get Position Dependent Executable (PDE) load address to be used to > > +# load static Position Independent Executable (PIE) at a known working > > +# non-zero load address. This is only used by glibc tests to verify > > +# that PIE and static PIE with non-zero load address work correctly. > > +AC_CACHE_CHECK([PDE load address], > > + libc_cv_pde_load_address, [dnl > > +cat > conftest.S <<EOF > > +.globl _start > > +_start: > > +.globl __start > > +__start: > > +EOF > > +if test $libc_cv_cc_pie_default = yes; then > > + pde_ld_flags="-no-pie" > > +fi > > +if ${CC-cc} $pde_ld_flags $CFLAGS $CPPFLAGS $LDFLAGS \ > > + -nostartfiles -nostdlib $no_ssp \ > > + -o conftest conftest.S 1>&AS_MESSAGE_LOG_FD 2>&AS_MESSAGE_LOG_FD; then > > + # Get the load address of the first PT_LOAD segment. > > + libc_cv_pde_load_address=$(LC_ALL=C $READELF -Wl conftest \ > > + | $AWK '/LOAD/ { print $3; exit 0; }') > > +else > > + AC_MSG_ERROR([${CC-cc} can not create PDE]) > > +fi > > +rm -f conftest*]) > > +LIBC_CONFIG_VAR([pde-load-address], [$libc_cv_pde_load_address]) > > + > > +# Get the linker command-line option to load executable at a non-zero > > +# load address. This is only used by glibc tests to verify that PIE and > > +# static PIE with non-zero load address work correctly. > > +LIBC_LINKER_FEATURE([-Ttext-segment=$libc_cv_pde_load_address], > > + [-Wl,-Ttext-segment=$libc_cv_pde_load_address], > > + [libc_cv_load_address_ldflag=-Wl,-Ttext-segment], > > + [libc_cv_load_address_ldflag=]) > > +LIBC_CONFIG_VAR([load-address-ldflag], [$libc_cv_load_address_ldflag]) > > + > > AC_MSG_CHECKING(if we can build programs as PIE) > > AC_COMPILE_IFELSE([AC_LANG_SOURCE([[#ifdef PIE_UNSUPPORTED > > # error PIE is not supported > > diff --git a/elf/Makefile b/elf/Makefile > > index 9cfe738919..4eaca7af67 100644 > > --- a/elf/Makefile > > +++ b/elf/Makefile > > @@ -1091,6 +1091,25 @@ tests-pie += \ > > tst-pie1 \ > > tst-pie2 \ > > # tests-pie > > +ifneq (,$(load-address-ldflag)) > > +tests += \ > > + tst-pie-address \ > > + # tests > > +tests-pie += \ > > + tst-pie-address \ > > + # tests-pie > > +LDFLAGS-tst-pie-address += $(load-address-ldflag)=$(pde-load-address) > > +ifeq (yes,$(enable-static-pie)) > > +tests += \ > > + tst-pie-address-static \ > > + # tests > > +tests-static += \ > > + tst-pie-address-static \ > > + # tests-static > > +LDFLAGS-tst-pie-address-static += \ > > + $(load-address-ldflag)=$(pde-load-address) > > +endif > > +endif > > ifeq (yes,$(have-protected-data)) > > tests += vismain > > tests-pie += vismain > > @@ -1937,6 +1956,7 @@ $(objpfx)tst-array5-static-cmp.out: tst-array5-static.exp \ > > > > CFLAGS-tst-pie1.c += $(pie-ccflag) > > CFLAGS-tst-pie2.c += $(pie-ccflag) > > +CFLAGS-tst-pie-address.c += $(pie-ccflag) > > > > $(objpfx)tst-piemod1.so: $(libsupport) > > $(objpfx)tst-pie1: $(objpfx)tst-piemod1.so > > diff --git a/elf/dl-reloc-static-pie.c b/elf/dl-reloc-static-pie.c > > index 10c23d0bf0..bfee89dfc3 100644 > > --- a/elf/dl-reloc-static-pie.c > > +++ b/elf/dl-reloc-static-pie.c > > @@ -37,21 +37,37 @@ _dl_relocate_static_pie (void) > > { > > struct link_map *main_map = _dl_get_dl_main_map (); > > > > - /* Figure out the run-time load address of static PIE. */ > > - main_map->l_addr = elf_machine_load_address (); > > - > > - /* Read our own dynamic section and fill in the info array. */ > > - main_map->l_ld = ((void *) main_map->l_addr + elf_machine_dynamic ()); > > - > > + /* NB: elf_machine_load_address () returns the run-time load address > > + of static PIE. The l_addr field contains the difference between the > > + link-time load address in the ELF file and the run-time load address > > + in memory. We must subtract the link-time load address of static PIE, > > + which can be non-zero, when computing the l_addr field. Since static > > + PIE usually doesn't have PT_PHDR segment, use p_vaddr of the PT_LOAD > > + segment with offset == 0 as the load address of static PIE. */ > > + ElfW(Addr) file_p_vaddr = 0; > > const ElfW(Phdr) *ph, *phdr = GL(dl_phdr); > > size_t phnum = GL(dl_phnum); > > for (ph = phdr; ph < &phdr[phnum]; ++ph) > > - if (ph->p_type == PT_DYNAMIC) > > + switch (ph->p_type) > > { > > + case PT_LOAD: > > + if (ph->p_offset == 0) > > + file_p_vaddr = ph->p_vaddr; > > + break; > > + case PT_DYNAMIC: > > main_map->l_ld_readonly = (ph->p_flags & PF_W) == 0; > > break; > > + default: > > + break; > > } > > > > + /* Figure out the run-time load address of static PIE. */ > > + ElfW(Addr) l_addr = elf_machine_load_address (); > > + main_map->l_addr = l_addr - file_p_vaddr; > > + > > + /* Read our own dynamic section and fill in the info array. */ > > + main_map->l_ld = ((void *) l_addr + elf_machine_dynamic ()); > > + > > elf_get_dynamic_info (main_map, false, true); > > > > # ifdef ELF_MACHINE_BEFORE_RTLD_RELOC > > diff --git a/elf/tst-pie-address-static.c b/elf/tst-pie-address-static.c > > new file mode 100644 > > index 0000000000..be2831e9d6 > > --- /dev/null > > +++ b/elf/tst-pie-address-static.c > > @@ -0,0 +1,19 @@ > > +/* Test static PIE with non-zero load address. > > + Copyright (C) 2024 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 > > + <https://www.gnu.org/licenses/>. */ > > + > > +#include "tst-pie-address.c" > > diff --git a/elf/tst-pie-address.c b/elf/tst-pie-address.c > > new file mode 100644 > > index 0000000000..aa1ca0a9fd > > --- /dev/null > > +++ b/elf/tst-pie-address.c > > @@ -0,0 +1,28 @@ > > +/* Test PIE with non-zero load address. > > + Copyright (C) 2024 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 > > + <https://www.gnu.org/licenses/>. */ > > + > > +#include <stdio.h> > > + > > +static int > > +do_test (void) > > +{ > > + printf ("Hello\n"); > > + return 0; > > +} > > + > > +#include <support/test-driver.c> > > -- > > 2.47.0 > > > > LGTM. > > Think Carlos was also going to take a look at this (from monday review > minutes), so please wait for Carlos to take a look too before pushing. Hi Carlos, Do you have comments? Thanks.
On Thu, Oct 31, 2024 at 7:55 AM H.J. Lu <hjl.tools@gmail.com> wrote: > > On Tue, Oct 29, 2024 at 1:33 PM Noah Goldstein <goldstein.w.n@gmail.com> wrote: > > > > On Mon, Oct 28, 2024 at 3:11 PM H.J. Lu <hjl.tools@gmail.com> wrote: > > > > > > For a static PIE with non-zero load address, its PT_DYNAMIC segment > > > entries contain the relocated values for the load address in static PIE. > > > Since static PIE usually doesn't have PT_PHDR segment, use p_vaddr of > > > the PT_LOAD segment with offset == 0 as the load address in static PIE > > > and adjust the entries of PT_DYNAMIC segment in static PIE by properly > > > setting the l_addr field for static PIE. This fixes BZ #31799. > > > > > > Signed-off-by: H.J. Lu <hjl.tools@gmail.com> > > > --- > > > configure | 74 ++++++++++++++++++++++++++++++++++++ > > > configure.ac | 36 ++++++++++++++++++ > > > elf/Makefile | 20 ++++++++++ > > > elf/dl-reloc-static-pie.c | 30 +++++++++++---- > > > elf/tst-pie-address-static.c | 19 +++++++++ > > > elf/tst-pie-address.c | 28 ++++++++++++++ > > > 6 files changed, 200 insertions(+), 7 deletions(-) > > > create mode 100644 elf/tst-pie-address-static.c > > > create mode 100644 elf/tst-pie-address.c > > > > > > diff --git a/configure b/configure > > > index 9c0c0dce03..9bcf62dca5 100755 > > > --- a/configure > > > +++ b/configure > > > @@ -8107,6 +8107,80 @@ printf "%s\n" "$libc_cv_cc_pie_default" >&6; } > > > config_vars="$config_vars > > > cc-pie-default = $libc_cv_cc_pie_default" > > > > > > +# Get Position Dependent Executable (PDE) load address to be used to > > > +# load static Position Independent Executable (PIE) at a known working > > > +# non-zero load address. This is only used by glibc tests to verify > > > +# that PIE and static PIE with non-zero load address work correctly. > > > +{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking PDE load address" >&5 > > > +printf %s "checking PDE load address... " >&6; } > > > +if test ${libc_cv_pde_load_address+y} > > > +then : > > > + printf %s "(cached) " >&6 > > > +else case e in #( > > > + e) cat > conftest.S <<EOF > > > +.globl _start > > > +_start: > > > +.globl __start > > > +__start: > > > +EOF > > > +if test $libc_cv_cc_pie_default = yes; then > > > + pde_ld_flags="-no-pie" > > > +fi > > > +if ${CC-cc} $pde_ld_flags $CFLAGS $CPPFLAGS $LDFLAGS \ > > > + -nostartfiles -nostdlib $no_ssp \ > > > + -o conftest conftest.S 1>&5 2>&5; then > > > + # Get the load address of the first PT_LOAD segment. > > > + libc_cv_pde_load_address=$(LC_ALL=C $READELF -Wl conftest \ > > > + | $AWK '/LOAD/ { print $3; exit 0; }') > > > +else > > > + as_fn_error $? "${CC-cc} can not create PDE" "$LINENO" 5 > > > +fi > > > +rm -f conftest* ;; > > > +esac > > > +fi > > > +{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $libc_cv_pde_load_address" >&5 > > > +printf "%s\n" "$libc_cv_pde_load_address" >&6; } > > > +config_vars="$config_vars > > > +pde-load-address = $libc_cv_pde_load_address" > > > + > > > +# Get the linker command-line option to load executable at a non-zero > > > +# load address. This is only used by glibc tests to verify that PIE and > > > +# static PIE with non-zero load address work correctly. > > > +{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for linker that supports -Ttext-segment=$libc_cv_pde_load_address" >&5 > > > +printf %s "checking for linker that supports -Ttext-segment=$libc_cv_pde_load_address... " >&6; } > > > +libc_linker_feature=no > > > +cat > conftest.c <<EOF > > > +int _start (void) { return 42; } > > > +EOF > > > +if { ac_try='${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS $no_ssp > > > + -Wl,-Ttext-segment=$libc_cv_pde_load_address -nostdlib -nostartfiles > > > + -fPIC -shared -o conftest.so conftest.c > > > + 1>&5' > > > + { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5 > > > + (eval $ac_try) 2>&5 > > > + ac_status=$? > > > + printf "%s\n" "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5 > > > + test $ac_status = 0; }; } > > > +then > > > + if ${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS $no_ssp -Wl,-Ttext-segment=$libc_cv_pde_load_address -nostdlib \ > > > + -nostartfiles -fPIC -shared -o conftest.so conftest.c 2>&1 \ > > > + | grep "warning: -Ttext-segment=$libc_cv_pde_load_address ignored" > /dev/null 2>&1; then > > > + true > > > + else > > > + libc_linker_feature=yes > > > + fi > > > +fi > > > +rm -f conftest* > > > +if test $libc_linker_feature = yes; then > > > + libc_cv_load_address_ldflag=-Wl,-Ttext-segment > > > +else > > > + libc_cv_load_address_ldflag= > > > +fi > > > +{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $libc_linker_feature" >&5 > > > +printf "%s\n" "$libc_linker_feature" >&6; } > > > +config_vars="$config_vars > > > +load-address-ldflag = $libc_cv_load_address_ldflag" > > > + > > > { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking if we can build programs as PIE" >&5 > > > printf %s "checking if we can build programs as PIE... " >&6; } > > > cat confdefs.h - <<_ACEOF >conftest.$ac_ext > > > diff --git a/configure.ac b/configure.ac > > > index d5a00461ff..895bd5267d 100644 > > > --- a/configure.ac > > > +++ b/configure.ac > > > @@ -1763,6 +1763,42 @@ fi > > > rm -f conftest.*]) > > > LIBC_CONFIG_VAR([cc-pie-default], [$libc_cv_cc_pie_default]) > > > > > > +# Get Position Dependent Executable (PDE) load address to be used to > > > +# load static Position Independent Executable (PIE) at a known working > > > +# non-zero load address. This is only used by glibc tests to verify > > > +# that PIE and static PIE with non-zero load address work correctly. > > > +AC_CACHE_CHECK([PDE load address], > > > + libc_cv_pde_load_address, [dnl > > > +cat > conftest.S <<EOF > > > +.globl _start > > > +_start: > > > +.globl __start > > > +__start: > > > +EOF > > > +if test $libc_cv_cc_pie_default = yes; then > > > + pde_ld_flags="-no-pie" > > > +fi > > > +if ${CC-cc} $pde_ld_flags $CFLAGS $CPPFLAGS $LDFLAGS \ > > > + -nostartfiles -nostdlib $no_ssp \ > > > + -o conftest conftest.S 1>&AS_MESSAGE_LOG_FD 2>&AS_MESSAGE_LOG_FD; then > > > + # Get the load address of the first PT_LOAD segment. > > > + libc_cv_pde_load_address=$(LC_ALL=C $READELF -Wl conftest \ > > > + | $AWK '/LOAD/ { print $3; exit 0; }') > > > +else > > > + AC_MSG_ERROR([${CC-cc} can not create PDE]) > > > +fi > > > +rm -f conftest*]) > > > +LIBC_CONFIG_VAR([pde-load-address], [$libc_cv_pde_load_address]) > > > + > > > +# Get the linker command-line option to load executable at a non-zero > > > +# load address. This is only used by glibc tests to verify that PIE and > > > +# static PIE with non-zero load address work correctly. > > > +LIBC_LINKER_FEATURE([-Ttext-segment=$libc_cv_pde_load_address], > > > + [-Wl,-Ttext-segment=$libc_cv_pde_load_address], > > > + [libc_cv_load_address_ldflag=-Wl,-Ttext-segment], > > > + [libc_cv_load_address_ldflag=]) > > > +LIBC_CONFIG_VAR([load-address-ldflag], [$libc_cv_load_address_ldflag]) > > > + > > > AC_MSG_CHECKING(if we can build programs as PIE) > > > AC_COMPILE_IFELSE([AC_LANG_SOURCE([[#ifdef PIE_UNSUPPORTED > > > # error PIE is not supported > > > diff --git a/elf/Makefile b/elf/Makefile > > > index 9cfe738919..4eaca7af67 100644 > > > --- a/elf/Makefile > > > +++ b/elf/Makefile > > > @@ -1091,6 +1091,25 @@ tests-pie += \ > > > tst-pie1 \ > > > tst-pie2 \ > > > # tests-pie > > > +ifneq (,$(load-address-ldflag)) > > > +tests += \ > > > + tst-pie-address \ > > > + # tests > > > +tests-pie += \ > > > + tst-pie-address \ > > > + # tests-pie > > > +LDFLAGS-tst-pie-address += $(load-address-ldflag)=$(pde-load-address) > > > +ifeq (yes,$(enable-static-pie)) > > > +tests += \ > > > + tst-pie-address-static \ > > > + # tests > > > +tests-static += \ > > > + tst-pie-address-static \ > > > + # tests-static > > > +LDFLAGS-tst-pie-address-static += \ > > > + $(load-address-ldflag)=$(pde-load-address) > > > +endif > > > +endif > > > ifeq (yes,$(have-protected-data)) > > > tests += vismain > > > tests-pie += vismain > > > @@ -1937,6 +1956,7 @@ $(objpfx)tst-array5-static-cmp.out: tst-array5-static.exp \ > > > > > > CFLAGS-tst-pie1.c += $(pie-ccflag) > > > CFLAGS-tst-pie2.c += $(pie-ccflag) > > > +CFLAGS-tst-pie-address.c += $(pie-ccflag) > > > > > > $(objpfx)tst-piemod1.so: $(libsupport) > > > $(objpfx)tst-pie1: $(objpfx)tst-piemod1.so > > > diff --git a/elf/dl-reloc-static-pie.c b/elf/dl-reloc-static-pie.c > > > index 10c23d0bf0..bfee89dfc3 100644 > > > --- a/elf/dl-reloc-static-pie.c > > > +++ b/elf/dl-reloc-static-pie.c > > > @@ -37,21 +37,37 @@ _dl_relocate_static_pie (void) > > > { > > > struct link_map *main_map = _dl_get_dl_main_map (); > > > > > > - /* Figure out the run-time load address of static PIE. */ > > > - main_map->l_addr = elf_machine_load_address (); > > > - > > > - /* Read our own dynamic section and fill in the info array. */ > > > - main_map->l_ld = ((void *) main_map->l_addr + elf_machine_dynamic ()); > > > - > > > + /* NB: elf_machine_load_address () returns the run-time load address > > > + of static PIE. The l_addr field contains the difference between the > > > + link-time load address in the ELF file and the run-time load address > > > + in memory. We must subtract the link-time load address of static PIE, > > > + which can be non-zero, when computing the l_addr field. Since static > > > + PIE usually doesn't have PT_PHDR segment, use p_vaddr of the PT_LOAD > > > + segment with offset == 0 as the load address of static PIE. */ > > > + ElfW(Addr) file_p_vaddr = 0; > > > const ElfW(Phdr) *ph, *phdr = GL(dl_phdr); > > > size_t phnum = GL(dl_phnum); > > > for (ph = phdr; ph < &phdr[phnum]; ++ph) > > > - if (ph->p_type == PT_DYNAMIC) > > > + switch (ph->p_type) > > > { > > > + case PT_LOAD: > > > + if (ph->p_offset == 0) > > > + file_p_vaddr = ph->p_vaddr; > > > + break; > > > + case PT_DYNAMIC: > > > main_map->l_ld_readonly = (ph->p_flags & PF_W) == 0; > > > break; > > > + default: > > > + break; > > > } > > > > > > + /* Figure out the run-time load address of static PIE. */ > > > + ElfW(Addr) l_addr = elf_machine_load_address (); > > > + main_map->l_addr = l_addr - file_p_vaddr; > > > + > > > + /* Read our own dynamic section and fill in the info array. */ > > > + main_map->l_ld = ((void *) l_addr + elf_machine_dynamic ()); > > > + > > > elf_get_dynamic_info (main_map, false, true); > > > > > > # ifdef ELF_MACHINE_BEFORE_RTLD_RELOC > > > diff --git a/elf/tst-pie-address-static.c b/elf/tst-pie-address-static.c > > > new file mode 100644 > > > index 0000000000..be2831e9d6 > > > --- /dev/null > > > +++ b/elf/tst-pie-address-static.c > > > @@ -0,0 +1,19 @@ > > > +/* Test static PIE with non-zero load address. > > > + Copyright (C) 2024 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 > > > + <https://www.gnu.org/licenses/>. */ > > > + > > > +#include "tst-pie-address.c" > > > diff --git a/elf/tst-pie-address.c b/elf/tst-pie-address.c > > > new file mode 100644 > > > index 0000000000..aa1ca0a9fd > > > --- /dev/null > > > +++ b/elf/tst-pie-address.c > > > @@ -0,0 +1,28 @@ > > > +/* Test PIE with non-zero load address. > > > + Copyright (C) 2024 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 > > > + <https://www.gnu.org/licenses/>. */ > > > + > > > +#include <stdio.h> > > > + > > > +static int > > > +do_test (void) > > > +{ > > > + printf ("Hello\n"); > > > + return 0; > > > +} > > > + > > > +#include <support/test-driver.c> > > > -- > > > 2.47.0 > > > > > > > LGTM. > > > > Think Carlos was also going to take a look at this (from monday review > > minutes), so please wait for Carlos to take a look too before pushing. > > Hi Carlos, > > Do you have comments? > > Thanks. > I will check it in tomorrow. Thanks.
On Sun, Nov 3, 2024 at 5:19 PM H.J. Lu <hjl.tools@gmail.com> wrote: > > On Thu, Oct 31, 2024 at 7:55 AM H.J. Lu <hjl.tools@gmail.com> wrote: > > > > On Tue, Oct 29, 2024 at 1:33 PM Noah Goldstein <goldstein.w.n@gmail.com> wrote: > > > > > > On Mon, Oct 28, 2024 at 3:11 PM H.J. Lu <hjl.tools@gmail.com> wrote: > > > > > > > > For a static PIE with non-zero load address, its PT_DYNAMIC segment > > > > entries contain the relocated values for the load address in static PIE. > > > > Since static PIE usually doesn't have PT_PHDR segment, use p_vaddr of > > > > the PT_LOAD segment with offset == 0 as the load address in static PIE > > > > and adjust the entries of PT_DYNAMIC segment in static PIE by properly > > > > setting the l_addr field for static PIE. This fixes BZ #31799. > > > > > > > > Signed-off-by: H.J. Lu <hjl.tools@gmail.com> > > > > --- > > > > configure | 74 ++++++++++++++++++++++++++++++++++++ > > > > configure.ac | 36 ++++++++++++++++++ > > > > elf/Makefile | 20 ++++++++++ > > > > elf/dl-reloc-static-pie.c | 30 +++++++++++---- > > > > elf/tst-pie-address-static.c | 19 +++++++++ > > > > elf/tst-pie-address.c | 28 ++++++++++++++ > > > > 6 files changed, 200 insertions(+), 7 deletions(-) > > > > create mode 100644 elf/tst-pie-address-static.c > > > > create mode 100644 elf/tst-pie-address.c > > > > > > > > diff --git a/configure b/configure > > > > index 9c0c0dce03..9bcf62dca5 100755 > > > > --- a/configure > > > > +++ b/configure > > > > @@ -8107,6 +8107,80 @@ printf "%s\n" "$libc_cv_cc_pie_default" >&6; } > > > > config_vars="$config_vars > > > > cc-pie-default = $libc_cv_cc_pie_default" > > > > > > > > +# Get Position Dependent Executable (PDE) load address to be used to > > > > +# load static Position Independent Executable (PIE) at a known working > > > > +# non-zero load address. This is only used by glibc tests to verify > > > > +# that PIE and static PIE with non-zero load address work correctly. > > > > +{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking PDE load address" >&5 > > > > +printf %s "checking PDE load address... " >&6; } > > > > +if test ${libc_cv_pde_load_address+y} > > > > +then : > > > > + printf %s "(cached) " >&6 > > > > +else case e in #( > > > > + e) cat > conftest.S <<EOF > > > > +.globl _start > > > > +_start: > > > > +.globl __start > > > > +__start: > > > > +EOF > > > > +if test $libc_cv_cc_pie_default = yes; then > > > > + pde_ld_flags="-no-pie" > > > > +fi > > > > +if ${CC-cc} $pde_ld_flags $CFLAGS $CPPFLAGS $LDFLAGS \ > > > > + -nostartfiles -nostdlib $no_ssp \ > > > > + -o conftest conftest.S 1>&5 2>&5; then > > > > + # Get the load address of the first PT_LOAD segment. > > > > + libc_cv_pde_load_address=$(LC_ALL=C $READELF -Wl conftest \ > > > > + | $AWK '/LOAD/ { print $3; exit 0; }') > > > > +else > > > > + as_fn_error $? "${CC-cc} can not create PDE" "$LINENO" 5 > > > > +fi > > > > +rm -f conftest* ;; > > > > +esac > > > > +fi > > > > +{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $libc_cv_pde_load_address" >&5 > > > > +printf "%s\n" "$libc_cv_pde_load_address" >&6; } > > > > +config_vars="$config_vars > > > > +pde-load-address = $libc_cv_pde_load_address" > > > > + > > > > +# Get the linker command-line option to load executable at a non-zero > > > > +# load address. This is only used by glibc tests to verify that PIE and > > > > +# static PIE with non-zero load address work correctly. > > > > +{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for linker that supports -Ttext-segment=$libc_cv_pde_load_address" >&5 > > > > +printf %s "checking for linker that supports -Ttext-segment=$libc_cv_pde_load_address... " >&6; } > > > > +libc_linker_feature=no > > > > +cat > conftest.c <<EOF > > > > +int _start (void) { return 42; } > > > > +EOF > > > > +if { ac_try='${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS $no_ssp > > > > + -Wl,-Ttext-segment=$libc_cv_pde_load_address -nostdlib -nostartfiles > > > > + -fPIC -shared -o conftest.so conftest.c > > > > + 1>&5' > > > > + { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5 > > > > + (eval $ac_try) 2>&5 > > > > + ac_status=$? > > > > + printf "%s\n" "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5 > > > > + test $ac_status = 0; }; } > > > > +then > > > > + if ${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS $no_ssp -Wl,-Ttext-segment=$libc_cv_pde_load_address -nostdlib \ > > > > + -nostartfiles -fPIC -shared -o conftest.so conftest.c 2>&1 \ > > > > + | grep "warning: -Ttext-segment=$libc_cv_pde_load_address ignored" > /dev/null 2>&1; then > > > > + true > > > > + else > > > > + libc_linker_feature=yes > > > > + fi > > > > +fi > > > > +rm -f conftest* > > > > +if test $libc_linker_feature = yes; then > > > > + libc_cv_load_address_ldflag=-Wl,-Ttext-segment > > > > +else > > > > + libc_cv_load_address_ldflag= > > > > +fi > > > > +{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $libc_linker_feature" >&5 > > > > +printf "%s\n" "$libc_linker_feature" >&6; } > > > > +config_vars="$config_vars > > > > +load-address-ldflag = $libc_cv_load_address_ldflag" > > > > + > > > > { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking if we can build programs as PIE" >&5 > > > > printf %s "checking if we can build programs as PIE... " >&6; } > > > > cat confdefs.h - <<_ACEOF >conftest.$ac_ext > > > > diff --git a/configure.ac b/configure.ac > > > > index d5a00461ff..895bd5267d 100644 > > > > --- a/configure.ac > > > > +++ b/configure.ac > > > > @@ -1763,6 +1763,42 @@ fi > > > > rm -f conftest.*]) > > > > LIBC_CONFIG_VAR([cc-pie-default], [$libc_cv_cc_pie_default]) > > > > > > > > +# Get Position Dependent Executable (PDE) load address to be used to > > > > +# load static Position Independent Executable (PIE) at a known working > > > > +# non-zero load address. This is only used by glibc tests to verify > > > > +# that PIE and static PIE with non-zero load address work correctly. > > > > +AC_CACHE_CHECK([PDE load address], > > > > + libc_cv_pde_load_address, [dnl > > > > +cat > conftest.S <<EOF > > > > +.globl _start > > > > +_start: > > > > +.globl __start > > > > +__start: > > > > +EOF > > > > +if test $libc_cv_cc_pie_default = yes; then > > > > + pde_ld_flags="-no-pie" > > > > +fi > > > > +if ${CC-cc} $pde_ld_flags $CFLAGS $CPPFLAGS $LDFLAGS \ > > > > + -nostartfiles -nostdlib $no_ssp \ > > > > + -o conftest conftest.S 1>&AS_MESSAGE_LOG_FD 2>&AS_MESSAGE_LOG_FD; then > > > > + # Get the load address of the first PT_LOAD segment. > > > > + libc_cv_pde_load_address=$(LC_ALL=C $READELF -Wl conftest \ > > > > + | $AWK '/LOAD/ { print $3; exit 0; }') > > > > +else > > > > + AC_MSG_ERROR([${CC-cc} can not create PDE]) > > > > +fi > > > > +rm -f conftest*]) > > > > +LIBC_CONFIG_VAR([pde-load-address], [$libc_cv_pde_load_address]) > > > > + > > > > +# Get the linker command-line option to load executable at a non-zero > > > > +# load address. This is only used by glibc tests to verify that PIE and > > > > +# static PIE with non-zero load address work correctly. > > > > +LIBC_LINKER_FEATURE([-Ttext-segment=$libc_cv_pde_load_address], > > > > + [-Wl,-Ttext-segment=$libc_cv_pde_load_address], > > > > + [libc_cv_load_address_ldflag=-Wl,-Ttext-segment], > > > > + [libc_cv_load_address_ldflag=]) > > > > +LIBC_CONFIG_VAR([load-address-ldflag], [$libc_cv_load_address_ldflag]) > > > > + > > > > AC_MSG_CHECKING(if we can build programs as PIE) > > > > AC_COMPILE_IFELSE([AC_LANG_SOURCE([[#ifdef PIE_UNSUPPORTED > > > > # error PIE is not supported > > > > diff --git a/elf/Makefile b/elf/Makefile > > > > index 9cfe738919..4eaca7af67 100644 > > > > --- a/elf/Makefile > > > > +++ b/elf/Makefile > > > > @@ -1091,6 +1091,25 @@ tests-pie += \ > > > > tst-pie1 \ > > > > tst-pie2 \ > > > > # tests-pie > > > > +ifneq (,$(load-address-ldflag)) > > > > +tests += \ > > > > + tst-pie-address \ > > > > + # tests > > > > +tests-pie += \ > > > > + tst-pie-address \ > > > > + # tests-pie > > > > +LDFLAGS-tst-pie-address += $(load-address-ldflag)=$(pde-load-address) > > > > +ifeq (yes,$(enable-static-pie)) > > > > +tests += \ > > > > + tst-pie-address-static \ > > > > + # tests > > > > +tests-static += \ > > > > + tst-pie-address-static \ > > > > + # tests-static > > > > +LDFLAGS-tst-pie-address-static += \ > > > > + $(load-address-ldflag)=$(pde-load-address) > > > > +endif > > > > +endif > > > > ifeq (yes,$(have-protected-data)) > > > > tests += vismain > > > > tests-pie += vismain > > > > @@ -1937,6 +1956,7 @@ $(objpfx)tst-array5-static-cmp.out: tst-array5-static.exp \ > > > > > > > > CFLAGS-tst-pie1.c += $(pie-ccflag) > > > > CFLAGS-tst-pie2.c += $(pie-ccflag) > > > > +CFLAGS-tst-pie-address.c += $(pie-ccflag) > > > > > > > > $(objpfx)tst-piemod1.so: $(libsupport) > > > > $(objpfx)tst-pie1: $(objpfx)tst-piemod1.so > > > > diff --git a/elf/dl-reloc-static-pie.c b/elf/dl-reloc-static-pie.c > > > > index 10c23d0bf0..bfee89dfc3 100644 > > > > --- a/elf/dl-reloc-static-pie.c > > > > +++ b/elf/dl-reloc-static-pie.c > > > > @@ -37,21 +37,37 @@ _dl_relocate_static_pie (void) > > > > { > > > > struct link_map *main_map = _dl_get_dl_main_map (); > > > > > > > > - /* Figure out the run-time load address of static PIE. */ > > > > - main_map->l_addr = elf_machine_load_address (); > > > > - > > > > - /* Read our own dynamic section and fill in the info array. */ > > > > - main_map->l_ld = ((void *) main_map->l_addr + elf_machine_dynamic ()); > > > > - > > > > + /* NB: elf_machine_load_address () returns the run-time load address > > > > + of static PIE. The l_addr field contains the difference between the > > > > + link-time load address in the ELF file and the run-time load address > > > > + in memory. We must subtract the link-time load address of static PIE, > > > > + which can be non-zero, when computing the l_addr field. Since static > > > > + PIE usually doesn't have PT_PHDR segment, use p_vaddr of the PT_LOAD > > > > + segment with offset == 0 as the load address of static PIE. */ > > > > + ElfW(Addr) file_p_vaddr = 0; > > > > const ElfW(Phdr) *ph, *phdr = GL(dl_phdr); > > > > size_t phnum = GL(dl_phnum); > > > > for (ph = phdr; ph < &phdr[phnum]; ++ph) > > > > - if (ph->p_type == PT_DYNAMIC) > > > > + switch (ph->p_type) > > > > { > > > > + case PT_LOAD: > > > > + if (ph->p_offset == 0) > > > > + file_p_vaddr = ph->p_vaddr; > > > > + break; > > > > + case PT_DYNAMIC: > > > > main_map->l_ld_readonly = (ph->p_flags & PF_W) == 0; > > > > break; > > > > + default: > > > > + break; > > > > } > > > > > > > > + /* Figure out the run-time load address of static PIE. */ > > > > + ElfW(Addr) l_addr = elf_machine_load_address (); > > > > + main_map->l_addr = l_addr - file_p_vaddr; > > > > + > > > > + /* Read our own dynamic section and fill in the info array. */ > > > > + main_map->l_ld = ((void *) l_addr + elf_machine_dynamic ()); > > > > + > > > > elf_get_dynamic_info (main_map, false, true); > > > > > > > > # ifdef ELF_MACHINE_BEFORE_RTLD_RELOC > > > > diff --git a/elf/tst-pie-address-static.c b/elf/tst-pie-address-static.c > > > > new file mode 100644 > > > > index 0000000000..be2831e9d6 > > > > --- /dev/null > > > > +++ b/elf/tst-pie-address-static.c > > > > @@ -0,0 +1,19 @@ > > > > +/* Test static PIE with non-zero load address. > > > > + Copyright (C) 2024 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 > > > > + <https://www.gnu.org/licenses/>. */ > > > > + > > > > +#include "tst-pie-address.c" > > > > diff --git a/elf/tst-pie-address.c b/elf/tst-pie-address.c > > > > new file mode 100644 > > > > index 0000000000..aa1ca0a9fd > > > > --- /dev/null > > > > +++ b/elf/tst-pie-address.c > > > > @@ -0,0 +1,28 @@ > > > > +/* Test PIE with non-zero load address. > > > > + Copyright (C) 2024 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 > > > > + <https://www.gnu.org/licenses/>. */ > > > > + > > > > +#include <stdio.h> > > > > + > > > > +static int > > > > +do_test (void) > > > > +{ > > > > + printf ("Hello\n"); > > > > + return 0; > > > > +} > > > > + > > > > +#include <support/test-driver.c> > > > > -- > > > > 2.47.0 > > > > > > > > > > LGTM. > > > > > > Think Carlos was also going to take a look at this (from monday review > > > minutes), so please wait for Carlos to take a look too before pushing. > > > > Hi Carlos, > > > > Do you have comments? > > > > Thanks. > > > > I will check it in tomorrow. > > Thanks. At least according to meeting notes, Carlos still wants to review this. > > -- > H.J.
On Tue, Nov 5, 2024, 12:39 AM Noah Goldstein <goldstein.w.n@gmail.com> wrote: > On Sun, Nov 3, 2024 at 5:19 PM H.J. Lu <hjl.tools@gmail.com> wrote: > > > > On Thu, Oct 31, 2024 at 7:55 AM H.J. Lu <hjl.tools@gmail.com> wrote: > > > > > > On Tue, Oct 29, 2024 at 1:33 PM Noah Goldstein < > goldstein.w.n@gmail.com> wrote: > > > > > > > > On Mon, Oct 28, 2024 at 3:11 PM H.J. Lu <hjl.tools@gmail.com> wrote: > > > > > > > > > > For a static PIE with non-zero load address, its PT_DYNAMIC segment > > > > > entries contain the relocated values for the load address in > static PIE. > > > > > Since static PIE usually doesn't have PT_PHDR segment, use p_vaddr > of > > > > > the PT_LOAD segment with offset == 0 as the load address in static > PIE > > > > > and adjust the entries of PT_DYNAMIC segment in static PIE by > properly > > > > > setting the l_addr field for static PIE. This fixes BZ #31799. > > > > > > > > > > Signed-off-by: H.J. Lu <hjl.tools@gmail.com> > > > > > --- > > > > > configure | 74 > ++++++++++++++++++++++++++++++++++++ > > > > > configure.ac | 36 ++++++++++++++++++ > > > > > elf/Makefile | 20 ++++++++++ > > > > > elf/dl-reloc-static-pie.c | 30 +++++++++++---- > > > > > elf/tst-pie-address-static.c | 19 +++++++++ > > > > > elf/tst-pie-address.c | 28 ++++++++++++++ > > > > > 6 files changed, 200 insertions(+), 7 deletions(-) > > > > > create mode 100644 elf/tst-pie-address-static.c > > > > > create mode 100644 elf/tst-pie-address.c > > > > > > > > > > diff --git a/configure b/configure > > > > > index 9c0c0dce03..9bcf62dca5 100755 > > > > > --- a/configure > > > > > +++ b/configure > > > > > @@ -8107,6 +8107,80 @@ printf "%s\n" "$libc_cv_cc_pie_default" > >&6; } > > > > > config_vars="$config_vars > > > > > cc-pie-default = $libc_cv_cc_pie_default" > > > > > > > > > > +# Get Position Dependent Executable (PDE) load address to be used > to > > > > > +# load static Position Independent Executable (PIE) at a known > working > > > > > +# non-zero load address. This is only used by glibc tests to > verify > > > > > +# that PIE and static PIE with non-zero load address work > correctly. > > > > > +{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking PDE load > address" >&5 > > > > > +printf %s "checking PDE load address... " >&6; } > > > > > +if test ${libc_cv_pde_load_address+y} > > > > > +then : > > > > > + printf %s "(cached) " >&6 > > > > > +else case e in #( > > > > > + e) cat > conftest.S <<EOF > > > > > +.globl _start > > > > > +_start: > > > > > +.globl __start > > > > > +__start: > > > > > +EOF > > > > > +if test $libc_cv_cc_pie_default = yes; then > > > > > + pde_ld_flags="-no-pie" > > > > > +fi > > > > > +if ${CC-cc} $pde_ld_flags $CFLAGS $CPPFLAGS $LDFLAGS \ > > > > > + -nostartfiles -nostdlib $no_ssp \ > > > > > + -o conftest conftest.S 1>&5 2>&5; then > > > > > + # Get the load address of the first PT_LOAD segment. > > > > > + libc_cv_pde_load_address=$(LC_ALL=C $READELF -Wl conftest \ > > > > > + | $AWK '/LOAD/ { print $3; exit 0; }') > > > > > +else > > > > > + as_fn_error $? "${CC-cc} can not create PDE" "$LINENO" 5 > > > > > +fi > > > > > +rm -f conftest* ;; > > > > > +esac > > > > > +fi > > > > > +{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: > $libc_cv_pde_load_address" >&5 > > > > > +printf "%s\n" "$libc_cv_pde_load_address" >&6; } > > > > > +config_vars="$config_vars > > > > > +pde-load-address = $libc_cv_pde_load_address" > > > > > + > > > > > +# Get the linker command-line option to load executable at a > non-zero > > > > > +# load address. This is only used by glibc tests to verify that > PIE and > > > > > +# static PIE with non-zero load address work correctly. > > > > > +{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for linker > that supports -Ttext-segment=$libc_cv_pde_load_address" >&5 > > > > > +printf %s "checking for linker that supports > -Ttext-segment=$libc_cv_pde_load_address... " >&6; } > > > > > +libc_linker_feature=no > > > > > +cat > conftest.c <<EOF > > > > > +int _start (void) { return 42; } > > > > > +EOF > > > > > +if { ac_try='${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS $no_ssp > > > > > + -Wl,-Ttext-segment=$libc_cv_pde_load_address > -nostdlib -nostartfiles > > > > > + -fPIC -shared -o conftest.so conftest.c > > > > > + 1>&5' > > > > > + { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; > } >&5 > > > > > + (eval $ac_try) 2>&5 > > > > > + ac_status=$? > > > > > + printf "%s\n" "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" > >&5 > > > > > + test $ac_status = 0; }; } > > > > > +then > > > > > + if ${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS $no_ssp > -Wl,-Ttext-segment=$libc_cv_pde_load_address -nostdlib \ > > > > > + -nostartfiles -fPIC -shared -o conftest.so conftest.c 2>&1 \ > > > > > + | grep "warning: -Ttext-segment=$libc_cv_pde_load_address > ignored" > /dev/null 2>&1; then > > > > > + true > > > > > + else > > > > > + libc_linker_feature=yes > > > > > + fi > > > > > +fi > > > > > +rm -f conftest* > > > > > +if test $libc_linker_feature = yes; then > > > > > + libc_cv_load_address_ldflag=-Wl,-Ttext-segment > > > > > +else > > > > > + libc_cv_load_address_ldflag= > > > > > +fi > > > > > +{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: > $libc_linker_feature" >&5 > > > > > +printf "%s\n" "$libc_linker_feature" >&6; } > > > > > +config_vars="$config_vars > > > > > +load-address-ldflag = $libc_cv_load_address_ldflag" > > > > > + > > > > > { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking if we can > build programs as PIE" >&5 > > > > > printf %s "checking if we can build programs as PIE... " >&6; } > > > > > cat confdefs.h - <<_ACEOF >conftest.$ac_ext > > > > > diff --git a/configure.ac b/configure.ac > > > > > index d5a00461ff..895bd5267d 100644 > > > > > --- a/configure.ac > > > > > +++ b/configure.ac > > > > > @@ -1763,6 +1763,42 @@ fi > > > > > rm -f conftest.*]) > > > > > LIBC_CONFIG_VAR([cc-pie-default], [$libc_cv_cc_pie_default]) > > > > > > > > > > +# Get Position Dependent Executable (PDE) load address to be used > to > > > > > +# load static Position Independent Executable (PIE) at a known > working > > > > > +# non-zero load address. This is only used by glibc tests to > verify > > > > > +# that PIE and static PIE with non-zero load address work > correctly. > > > > > +AC_CACHE_CHECK([PDE load address], > > > > > + libc_cv_pde_load_address, [dnl > > > > > +cat > conftest.S <<EOF > > > > > +.globl _start > > > > > +_start: > > > > > +.globl __start > > > > > +__start: > > > > > +EOF > > > > > +if test $libc_cv_cc_pie_default = yes; then > > > > > + pde_ld_flags="-no-pie" > > > > > +fi > > > > > +if ${CC-cc} $pde_ld_flags $CFLAGS $CPPFLAGS $LDFLAGS \ > > > > > + -nostartfiles -nostdlib $no_ssp \ > > > > > + -o conftest conftest.S 1>&AS_MESSAGE_LOG_FD > 2>&AS_MESSAGE_LOG_FD; then > > > > > + # Get the load address of the first PT_LOAD segment. > > > > > + libc_cv_pde_load_address=$(LC_ALL=C $READELF -Wl conftest \ > > > > > + | $AWK '/LOAD/ { print $3; exit 0; }') > > > > > +else > > > > > + AC_MSG_ERROR([${CC-cc} can not create PDE]) > > > > > +fi > > > > > +rm -f conftest*]) > > > > > +LIBC_CONFIG_VAR([pde-load-address], [$libc_cv_pde_load_address]) > > > > > + > > > > > +# Get the linker command-line option to load executable at a > non-zero > > > > > +# load address. This is only used by glibc tests to verify that > PIE and > > > > > +# static PIE with non-zero load address work correctly. > > > > > +LIBC_LINKER_FEATURE([-Ttext-segment=$libc_cv_pde_load_address], > > > > > + [-Wl,-Ttext-segment=$libc_cv_pde_load_address], > > > > > + > [libc_cv_load_address_ldflag=-Wl,-Ttext-segment], > > > > > + [libc_cv_load_address_ldflag=]) > > > > > +LIBC_CONFIG_VAR([load-address-ldflag], > [$libc_cv_load_address_ldflag]) > > > > > + > > > > > AC_MSG_CHECKING(if we can build programs as PIE) > > > > > AC_COMPILE_IFELSE([AC_LANG_SOURCE([[#ifdef PIE_UNSUPPORTED > > > > > # error PIE is not supported > > > > > diff --git a/elf/Makefile b/elf/Makefile > > > > > index 9cfe738919..4eaca7af67 100644 > > > > > --- a/elf/Makefile > > > > > +++ b/elf/Makefile > > > > > @@ -1091,6 +1091,25 @@ tests-pie += \ > > > > > tst-pie1 \ > > > > > tst-pie2 \ > > > > > # tests-pie > > > > > +ifneq (,$(load-address-ldflag)) > > > > > +tests += \ > > > > > + tst-pie-address \ > > > > > + # tests > > > > > +tests-pie += \ > > > > > + tst-pie-address \ > > > > > + # tests-pie > > > > > +LDFLAGS-tst-pie-address += > $(load-address-ldflag)=$(pde-load-address) > > > > > +ifeq (yes,$(enable-static-pie)) > > > > > +tests += \ > > > > > + tst-pie-address-static \ > > > > > + # tests > > > > > +tests-static += \ > > > > > + tst-pie-address-static \ > > > > > + # tests-static > > > > > +LDFLAGS-tst-pie-address-static += \ > > > > > + $(load-address-ldflag)=$(pde-load-address) > > > > > +endif > > > > > +endif > > > > > ifeq (yes,$(have-protected-data)) > > > > > tests += vismain > > > > > tests-pie += vismain > > > > > @@ -1937,6 +1956,7 @@ $(objpfx)tst-array5-static-cmp.out: > tst-array5-static.exp \ > > > > > > > > > > CFLAGS-tst-pie1.c += $(pie-ccflag) > > > > > CFLAGS-tst-pie2.c += $(pie-ccflag) > > > > > +CFLAGS-tst-pie-address.c += $(pie-ccflag) > > > > > > > > > > $(objpfx)tst-piemod1.so: $(libsupport) > > > > > $(objpfx)tst-pie1: $(objpfx)tst-piemod1.so > > > > > diff --git a/elf/dl-reloc-static-pie.c b/elf/dl-reloc-static-pie.c > > > > > index 10c23d0bf0..bfee89dfc3 100644 > > > > > --- a/elf/dl-reloc-static-pie.c > > > > > +++ b/elf/dl-reloc-static-pie.c > > > > > @@ -37,21 +37,37 @@ _dl_relocate_static_pie (void) > > > > > { > > > > > struct link_map *main_map = _dl_get_dl_main_map (); > > > > > > > > > > - /* Figure out the run-time load address of static PIE. */ > > > > > - main_map->l_addr = elf_machine_load_address (); > > > > > - > > > > > - /* Read our own dynamic section and fill in the info array. */ > > > > > - main_map->l_ld = ((void *) main_map->l_addr + > elf_machine_dynamic ()); > > > > > - > > > > > + /* NB: elf_machine_load_address () returns the run-time load > address > > > > > + of static PIE. The l_addr field contains the difference > between the > > > > > + link-time load address in the ELF file and the run-time load > address > > > > > + in memory. We must subtract the link-time load address of > static PIE, > > > > > + which can be non-zero, when computing the l_addr field. > Since static > > > > > + PIE usually doesn't have PT_PHDR segment, use p_vaddr of the > PT_LOAD > > > > > + segment with offset == 0 as the load address of static PIE. > */ > > > > > + ElfW(Addr) file_p_vaddr = 0; > > > > > const ElfW(Phdr) *ph, *phdr = GL(dl_phdr); > > > > > size_t phnum = GL(dl_phnum); > > > > > for (ph = phdr; ph < &phdr[phnum]; ++ph) > > > > > - if (ph->p_type == PT_DYNAMIC) > > > > > + switch (ph->p_type) > > > > > { > > > > > + case PT_LOAD: > > > > > + if (ph->p_offset == 0) > > > > > + file_p_vaddr = ph->p_vaddr; > > > > > + break; > > > > > + case PT_DYNAMIC: > > > > > main_map->l_ld_readonly = (ph->p_flags & PF_W) == 0; > > > > > break; > > > > > + default: > > > > > + break; > > > > > } > > > > > > > > > > + /* Figure out the run-time load address of static PIE. */ > > > > > + ElfW(Addr) l_addr = elf_machine_load_address (); > > > > > + main_map->l_addr = l_addr - file_p_vaddr; > > > > > + > > > > > + /* Read our own dynamic section and fill in the info array. */ > > > > > + main_map->l_ld = ((void *) l_addr + elf_machine_dynamic ()); > > > > > + > > > > > elf_get_dynamic_info (main_map, false, true); > > > > > > > > > > # ifdef ELF_MACHINE_BEFORE_RTLD_RELOC > > > > > diff --git a/elf/tst-pie-address-static.c > b/elf/tst-pie-address-static.c > > > > > new file mode 100644 > > > > > index 0000000000..be2831e9d6 > > > > > --- /dev/null > > > > > +++ b/elf/tst-pie-address-static.c > > > > > @@ -0,0 +1,19 @@ > > > > > +/* Test static PIE with non-zero load address. > > > > > + Copyright (C) 2024 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 > > > > > + <https://www.gnu.org/licenses/>. */ > > > > > + > > > > > +#include "tst-pie-address.c" > > > > > diff --git a/elf/tst-pie-address.c b/elf/tst-pie-address.c > > > > > new file mode 100644 > > > > > index 0000000000..aa1ca0a9fd > > > > > --- /dev/null > > > > > +++ b/elf/tst-pie-address.c > > > > > @@ -0,0 +1,28 @@ > > > > > +/* Test PIE with non-zero load address. > > > > > + Copyright (C) 2024 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 > > > > > + <https://www.gnu.org/licenses/>. */ > > > > > + > > > > > +#include <stdio.h> > > > > > + > > > > > +static int > > > > > +do_test (void) > > > > > +{ > > > > > + printf ("Hello\n"); > > > > > + return 0; > > > > > +} > > > > > + > > > > > +#include <support/test-driver.c> > > > > > -- > > > > > 2.47.0 > > > > > > > > > > > > > LGTM. > > > > > > > > Think Carlos was also going to take a look at this (from monday > review > > > > minutes), so please wait for Carlos to take a look too before > pushing. > > > > > > Hi Carlos, > > > > > > Do you have comments? > > > > > > Thanks. > > > > > > > I will check it in tomorrow. > > > > Thanks. > > At least according to meeting notes, Carlos still wants to review this. > Hi Carlos, Any estimate when you can review it? > > > -- > > H.J. > >
On Tue, Nov 5, 2024, 5:37 AM H.J. Lu <hjl.tools@gmail.com> wrote: > > On Tue, Nov 5, 2024, 12:39 AM Noah Goldstein <goldstein.w.n@gmail.com> > wrote: > >> On Sun, Nov 3, 2024 at 5:19 PM H.J. Lu <hjl.tools@gmail.com> wrote: >> > >> > On Thu, Oct 31, 2024 at 7:55 AM H.J. Lu <hjl.tools@gmail.com> wrote: >> > > >> > > On Tue, Oct 29, 2024 at 1:33 PM Noah Goldstein < >> goldstein.w.n@gmail.com> wrote: >> > > > >> > > > On Mon, Oct 28, 2024 at 3:11 PM H.J. Lu <hjl.tools@gmail.com> >> wrote: >> > > > > >> > > > > For a static PIE with non-zero load address, its PT_DYNAMIC >> segment >> > > > > entries contain the relocated values for the load address in >> static PIE. >> > > > > Since static PIE usually doesn't have PT_PHDR segment, use >> p_vaddr of >> > > > > the PT_LOAD segment with offset == 0 as the load address in >> static PIE >> > > > > and adjust the entries of PT_DYNAMIC segment in static PIE by >> properly >> > > > > setting the l_addr field for static PIE. This fixes BZ #31799. >> > > > > >> > > > > Signed-off-by: H.J. Lu <hjl.tools@gmail.com> >> > > > > --- >> > > > > configure | 74 >> ++++++++++++++++++++++++++++++++++++ >> > > > > configure.ac | 36 ++++++++++++++++++ >> > > > > elf/Makefile | 20 ++++++++++ >> > > > > elf/dl-reloc-static-pie.c | 30 +++++++++++---- >> > > > > elf/tst-pie-address-static.c | 19 +++++++++ >> > > > > elf/tst-pie-address.c | 28 ++++++++++++++ >> > > > > 6 files changed, 200 insertions(+), 7 deletions(-) >> > > > > create mode 100644 elf/tst-pie-address-static.c >> > > > > create mode 100644 elf/tst-pie-address.c >> > > > > >> > > > > diff --git a/configure b/configure >> > > > > index 9c0c0dce03..9bcf62dca5 100755 >> > > > > --- a/configure >> > > > > +++ b/configure >> > > > > @@ -8107,6 +8107,80 @@ printf "%s\n" "$libc_cv_cc_pie_default" >> >&6; } >> > > > > config_vars="$config_vars >> > > > > cc-pie-default = $libc_cv_cc_pie_default" >> > > > > >> > > > > +# Get Position Dependent Executable (PDE) load address to be >> used to >> > > > > +# load static Position Independent Executable (PIE) at a known >> working >> > > > > +# non-zero load address. This is only used by glibc tests to >> verify >> > > > > +# that PIE and static PIE with non-zero load address work >> correctly. >> > > > > +{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking PDE load >> address" >&5 >> > > > > +printf %s "checking PDE load address... " >&6; } >> > > > > +if test ${libc_cv_pde_load_address+y} >> > > > > +then : >> > > > > + printf %s "(cached) " >&6 >> > > > > +else case e in #( >> > > > > + e) cat > conftest.S <<EOF >> > > > > +.globl _start >> > > > > +_start: >> > > > > +.globl __start >> > > > > +__start: >> > > > > +EOF >> > > > > +if test $libc_cv_cc_pie_default = yes; then >> > > > > + pde_ld_flags="-no-pie" >> > > > > +fi >> > > > > +if ${CC-cc} $pde_ld_flags $CFLAGS $CPPFLAGS $LDFLAGS \ >> > > > > + -nostartfiles -nostdlib $no_ssp \ >> > > > > + -o conftest conftest.S 1>&5 2>&5; then >> > > > > + # Get the load address of the first PT_LOAD segment. >> > > > > + libc_cv_pde_load_address=$(LC_ALL=C $READELF -Wl conftest \ >> > > > > + | $AWK '/LOAD/ { print $3; exit 0; >> }') >> > > > > +else >> > > > > + as_fn_error $? "${CC-cc} can not create PDE" "$LINENO" 5 >> > > > > +fi >> > > > > +rm -f conftest* ;; >> > > > > +esac >> > > > > +fi >> > > > > +{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: >> $libc_cv_pde_load_address" >&5 >> > > > > +printf "%s\n" "$libc_cv_pde_load_address" >&6; } >> > > > > +config_vars="$config_vars >> > > > > +pde-load-address = $libc_cv_pde_load_address" >> > > > > + >> > > > > +# Get the linker command-line option to load executable at a >> non-zero >> > > > > +# load address. This is only used by glibc tests to verify that >> PIE and >> > > > > +# static PIE with non-zero load address work correctly. >> > > > > +{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for >> linker that supports -Ttext-segment=$libc_cv_pde_load_address" >&5 >> > > > > +printf %s "checking for linker that supports >> -Ttext-segment=$libc_cv_pde_load_address... " >&6; } >> > > > > +libc_linker_feature=no >> > > > > +cat > conftest.c <<EOF >> > > > > +int _start (void) { return 42; } >> > > > > +EOF >> > > > > +if { ac_try='${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS $no_ssp >> > > > > + -Wl,-Ttext-segment=$libc_cv_pde_load_address >> -nostdlib -nostartfiles >> > > > > + -fPIC -shared -o conftest.so conftest.c >> > > > > + 1>&5' >> > > > > + { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; >> } >&5 >> > > > > + (eval $ac_try) 2>&5 >> > > > > + ac_status=$? >> > > > > + printf "%s\n" "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >> >&5 >> > > > > + test $ac_status = 0; }; } >> > > > > +then >> > > > > + if ${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS $no_ssp >> -Wl,-Ttext-segment=$libc_cv_pde_load_address -nostdlib \ >> > > > > + -nostartfiles -fPIC -shared -o conftest.so conftest.c 2>&1 >> \ >> > > > > + | grep "warning: -Ttext-segment=$libc_cv_pde_load_address >> ignored" > /dev/null 2>&1; then >> > > > > + true >> > > > > + else >> > > > > + libc_linker_feature=yes >> > > > > + fi >> > > > > +fi >> > > > > +rm -f conftest* >> > > > > +if test $libc_linker_feature = yes; then >> > > > > + libc_cv_load_address_ldflag=-Wl,-Ttext-segment >> > > > > +else >> > > > > + libc_cv_load_address_ldflag= >> > > > > +fi >> > > > > +{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: >> $libc_linker_feature" >&5 >> > > > > +printf "%s\n" "$libc_linker_feature" >&6; } >> > > > > +config_vars="$config_vars >> > > > > +load-address-ldflag = $libc_cv_load_address_ldflag" >> > > > > + >> > > > > { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking if we can >> build programs as PIE" >&5 >> > > > > printf %s "checking if we can build programs as PIE... " >&6; } >> > > > > cat confdefs.h - <<_ACEOF >conftest.$ac_ext >> > > > > diff --git a/configure.ac b/configure.ac >> > > > > index d5a00461ff..895bd5267d 100644 >> > > > > --- a/configure.ac >> > > > > +++ b/configure.ac >> > > > > @@ -1763,6 +1763,42 @@ fi >> > > > > rm -f conftest.*]) >> > > > > LIBC_CONFIG_VAR([cc-pie-default], [$libc_cv_cc_pie_default]) >> > > > > >> > > > > +# Get Position Dependent Executable (PDE) load address to be >> used to >> > > > > +# load static Position Independent Executable (PIE) at a known >> working >> > > > > +# non-zero load address. This is only used by glibc tests to >> verify >> > > > > +# that PIE and static PIE with non-zero load address work >> correctly. >> > > > > +AC_CACHE_CHECK([PDE load address], >> > > > > + libc_cv_pde_load_address, [dnl >> > > > > +cat > conftest.S <<EOF >> > > > > +.globl _start >> > > > > +_start: >> > > > > +.globl __start >> > > > > +__start: >> > > > > +EOF >> > > > > +if test $libc_cv_cc_pie_default = yes; then >> > > > > + pde_ld_flags="-no-pie" >> > > > > +fi >> > > > > +if ${CC-cc} $pde_ld_flags $CFLAGS $CPPFLAGS $LDFLAGS \ >> > > > > + -nostartfiles -nostdlib $no_ssp \ >> > > > > + -o conftest conftest.S 1>&AS_MESSAGE_LOG_FD >> 2>&AS_MESSAGE_LOG_FD; then >> > > > > + # Get the load address of the first PT_LOAD segment. >> > > > > + libc_cv_pde_load_address=$(LC_ALL=C $READELF -Wl conftest \ >> > > > > + | $AWK '/LOAD/ { print $3; exit 0; >> }') >> > > > > +else >> > > > > + AC_MSG_ERROR([${CC-cc} can not create PDE]) >> > > > > +fi >> > > > > +rm -f conftest*]) >> > > > > +LIBC_CONFIG_VAR([pde-load-address], [$libc_cv_pde_load_address]) >> > > > > + >> > > > > +# Get the linker command-line option to load executable at a >> non-zero >> > > > > +# load address. This is only used by glibc tests to verify that >> PIE and >> > > > > +# static PIE with non-zero load address work correctly. >> > > > > +LIBC_LINKER_FEATURE([-Ttext-segment=$libc_cv_pde_load_address], >> > > > > + >> [-Wl,-Ttext-segment=$libc_cv_pde_load_address], >> > > > > + >> [libc_cv_load_address_ldflag=-Wl,-Ttext-segment], >> > > > > + [libc_cv_load_address_ldflag=]) >> > > > > +LIBC_CONFIG_VAR([load-address-ldflag], >> [$libc_cv_load_address_ldflag]) >> > > > > + >> > > > > AC_MSG_CHECKING(if we can build programs as PIE) >> > > > > AC_COMPILE_IFELSE([AC_LANG_SOURCE([[#ifdef PIE_UNSUPPORTED >> > > > > # error PIE is not supported >> > > > > diff --git a/elf/Makefile b/elf/Makefile >> > > > > index 9cfe738919..4eaca7af67 100644 >> > > > > --- a/elf/Makefile >> > > > > +++ b/elf/Makefile >> > > > > @@ -1091,6 +1091,25 @@ tests-pie += \ >> > > > > tst-pie1 \ >> > > > > tst-pie2 \ >> > > > > # tests-pie >> > > > > +ifneq (,$(load-address-ldflag)) >> > > > > +tests += \ >> > > > > + tst-pie-address \ >> > > > > + # tests >> > > > > +tests-pie += \ >> > > > > + tst-pie-address \ >> > > > > + # tests-pie >> > > > > +LDFLAGS-tst-pie-address += >> $(load-address-ldflag)=$(pde-load-address) >> > > > > +ifeq (yes,$(enable-static-pie)) >> > > > > +tests += \ >> > > > > + tst-pie-address-static \ >> > > > > + # tests >> > > > > +tests-static += \ >> > > > > + tst-pie-address-static \ >> > > > > + # tests-static >> > > > > +LDFLAGS-tst-pie-address-static += \ >> > > > > + $(load-address-ldflag)=$(pde-load-address) >> > > > > +endif >> > > > > +endif >> > > > > ifeq (yes,$(have-protected-data)) >> > > > > tests += vismain >> > > > > tests-pie += vismain >> > > > > @@ -1937,6 +1956,7 @@ $(objpfx)tst-array5-static-cmp.out: >> tst-array5-static.exp \ >> > > > > >> > > > > CFLAGS-tst-pie1.c += $(pie-ccflag) >> > > > > CFLAGS-tst-pie2.c += $(pie-ccflag) >> > > > > +CFLAGS-tst-pie-address.c += $(pie-ccflag) >> > > > > >> > > > > $(objpfx)tst-piemod1.so: $(libsupport) >> > > > > $(objpfx)tst-pie1: $(objpfx)tst-piemod1.so >> > > > > diff --git a/elf/dl-reloc-static-pie.c b/elf/dl-reloc-static-pie.c >> > > > > index 10c23d0bf0..bfee89dfc3 100644 >> > > > > --- a/elf/dl-reloc-static-pie.c >> > > > > +++ b/elf/dl-reloc-static-pie.c >> > > > > @@ -37,21 +37,37 @@ _dl_relocate_static_pie (void) >> > > > > { >> > > > > struct link_map *main_map = _dl_get_dl_main_map (); >> > > > > >> > > > > - /* Figure out the run-time load address of static PIE. */ >> > > > > - main_map->l_addr = elf_machine_load_address (); >> > > > > - >> > > > > - /* Read our own dynamic section and fill in the info array. */ >> > > > > - main_map->l_ld = ((void *) main_map->l_addr + >> elf_machine_dynamic ()); >> > > > > - >> > > > > + /* NB: elf_machine_load_address () returns the run-time load >> address >> > > > > + of static PIE. The l_addr field contains the difference >> between the >> > > > > + link-time load address in the ELF file and the run-time >> load address >> > > > > + in memory. We must subtract the link-time load address of >> static PIE, >> > > > > + which can be non-zero, when computing the l_addr field. >> Since static >> > > > > + PIE usually doesn't have PT_PHDR segment, use p_vaddr of >> the PT_LOAD >> > > > > + segment with offset == 0 as the load address of static >> PIE. */ >> > > > > + ElfW(Addr) file_p_vaddr = 0; >> > > > > const ElfW(Phdr) *ph, *phdr = GL(dl_phdr); >> > > > > size_t phnum = GL(dl_phnum); >> > > > > for (ph = phdr; ph < &phdr[phnum]; ++ph) >> > > > > - if (ph->p_type == PT_DYNAMIC) >> > > > > + switch (ph->p_type) >> > > > > { >> > > > > + case PT_LOAD: >> > > > > + if (ph->p_offset == 0) >> > > > > + file_p_vaddr = ph->p_vaddr; >> > > > > + break; >> > > > > + case PT_DYNAMIC: >> > > > > main_map->l_ld_readonly = (ph->p_flags & PF_W) == 0; >> > > > > break; >> > > > > + default: >> > > > > + break; >> > > > > } >> > > > > >> > > > > + /* Figure out the run-time load address of static PIE. */ >> > > > > + ElfW(Addr) l_addr = elf_machine_load_address (); >> > > > > + main_map->l_addr = l_addr - file_p_vaddr; >> > > > > + >> > > > > + /* Read our own dynamic section and fill in the info array. */ >> > > > > + main_map->l_ld = ((void *) l_addr + elf_machine_dynamic ()); >> > > > > + >> > > > > elf_get_dynamic_info (main_map, false, true); >> > > > > >> > > > > # ifdef ELF_MACHINE_BEFORE_RTLD_RELOC >> > > > > diff --git a/elf/tst-pie-address-static.c >> b/elf/tst-pie-address-static.c >> > > > > new file mode 100644 >> > > > > index 0000000000..be2831e9d6 >> > > > > --- /dev/null >> > > > > +++ b/elf/tst-pie-address-static.c >> > > > > @@ -0,0 +1,19 @@ >> > > > > +/* Test static PIE with non-zero load address. >> > > > > + Copyright (C) 2024 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 >> > > > > + <https://www.gnu.org/licenses/>. */ >> > > > > + >> > > > > +#include "tst-pie-address.c" >> > > > > diff --git a/elf/tst-pie-address.c b/elf/tst-pie-address.c >> > > > > new file mode 100644 >> > > > > index 0000000000..aa1ca0a9fd >> > > > > --- /dev/null >> > > > > +++ b/elf/tst-pie-address.c >> > > > > @@ -0,0 +1,28 @@ >> > > > > +/* Test PIE with non-zero load address. >> > > > > + Copyright (C) 2024 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 >> > > > > + <https://www.gnu.org/licenses/>. */ >> > > > > + >> > > > > +#include <stdio.h> >> > > > > + >> > > > > +static int >> > > > > +do_test (void) >> > > > > +{ >> > > > > + printf ("Hello\n"); >> > > > > + return 0; >> > > > > +} >> > > > > + >> > > > > +#include <support/test-driver.c> >> > > > > -- >> > > > > 2.47.0 >> > > > > >> > > > >> > > > LGTM. >> > > > >> > > > Think Carlos was also going to take a look at this (from monday >> review >> > > > minutes), so please wait for Carlos to take a look too before >> pushing. >> > > >> > > Hi Carlos, >> > > >> > > Do you have comments? >> > > >> > > Thanks. >> > > >> > >> > I will check it in tomorrow. >> > >> > Thanks. >> >> At least according to meeting notes, Carlos still wants to review this. >> > > Hi Carlos, > > Any estimate when you can review it? > I will check it in this week. > > >> > -- >> > H.J. >> >> >>
diff --git a/configure b/configure index 9c0c0dce03..9bcf62dca5 100755 --- a/configure +++ b/configure @@ -8107,6 +8107,80 @@ printf "%s\n" "$libc_cv_cc_pie_default" >&6; } config_vars="$config_vars cc-pie-default = $libc_cv_cc_pie_default" +# Get Position Dependent Executable (PDE) load address to be used to +# load static Position Independent Executable (PIE) at a known working +# non-zero load address. This is only used by glibc tests to verify +# that PIE and static PIE with non-zero load address work correctly. +{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking PDE load address" >&5 +printf %s "checking PDE load address... " >&6; } +if test ${libc_cv_pde_load_address+y} +then : + printf %s "(cached) " >&6 +else case e in #( + e) cat > conftest.S <<EOF +.globl _start +_start: +.globl __start +__start: +EOF +if test $libc_cv_cc_pie_default = yes; then + pde_ld_flags="-no-pie" +fi +if ${CC-cc} $pde_ld_flags $CFLAGS $CPPFLAGS $LDFLAGS \ + -nostartfiles -nostdlib $no_ssp \ + -o conftest conftest.S 1>&5 2>&5; then + # Get the load address of the first PT_LOAD segment. + libc_cv_pde_load_address=$(LC_ALL=C $READELF -Wl conftest \ + | $AWK '/LOAD/ { print $3; exit 0; }') +else + as_fn_error $? "${CC-cc} can not create PDE" "$LINENO" 5 +fi +rm -f conftest* ;; +esac +fi +{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $libc_cv_pde_load_address" >&5 +printf "%s\n" "$libc_cv_pde_load_address" >&6; } +config_vars="$config_vars +pde-load-address = $libc_cv_pde_load_address" + +# Get the linker command-line option to load executable at a non-zero +# load address. This is only used by glibc tests to verify that PIE and +# static PIE with non-zero load address work correctly. +{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for linker that supports -Ttext-segment=$libc_cv_pde_load_address" >&5 +printf %s "checking for linker that supports -Ttext-segment=$libc_cv_pde_load_address... " >&6; } +libc_linker_feature=no +cat > conftest.c <<EOF +int _start (void) { return 42; } +EOF +if { ac_try='${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS $no_ssp + -Wl,-Ttext-segment=$libc_cv_pde_load_address -nostdlib -nostartfiles + -fPIC -shared -o conftest.so conftest.c + 1>&5' + { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5 + (eval $ac_try) 2>&5 + ac_status=$? + printf "%s\n" "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5 + test $ac_status = 0; }; } +then + if ${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS $no_ssp -Wl,-Ttext-segment=$libc_cv_pde_load_address -nostdlib \ + -nostartfiles -fPIC -shared -o conftest.so conftest.c 2>&1 \ + | grep "warning: -Ttext-segment=$libc_cv_pde_load_address ignored" > /dev/null 2>&1; then + true + else + libc_linker_feature=yes + fi +fi +rm -f conftest* +if test $libc_linker_feature = yes; then + libc_cv_load_address_ldflag=-Wl,-Ttext-segment +else + libc_cv_load_address_ldflag= +fi +{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $libc_linker_feature" >&5 +printf "%s\n" "$libc_linker_feature" >&6; } +config_vars="$config_vars +load-address-ldflag = $libc_cv_load_address_ldflag" + { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking if we can build programs as PIE" >&5 printf %s "checking if we can build programs as PIE... " >&6; } cat confdefs.h - <<_ACEOF >conftest.$ac_ext diff --git a/configure.ac b/configure.ac index d5a00461ff..895bd5267d 100644 --- a/configure.ac +++ b/configure.ac @@ -1763,6 +1763,42 @@ fi rm -f conftest.*]) LIBC_CONFIG_VAR([cc-pie-default], [$libc_cv_cc_pie_default]) +# Get Position Dependent Executable (PDE) load address to be used to +# load static Position Independent Executable (PIE) at a known working +# non-zero load address. This is only used by glibc tests to verify +# that PIE and static PIE with non-zero load address work correctly. +AC_CACHE_CHECK([PDE load address], + libc_cv_pde_load_address, [dnl +cat > conftest.S <<EOF +.globl _start +_start: +.globl __start +__start: +EOF +if test $libc_cv_cc_pie_default = yes; then + pde_ld_flags="-no-pie" +fi +if ${CC-cc} $pde_ld_flags $CFLAGS $CPPFLAGS $LDFLAGS \ + -nostartfiles -nostdlib $no_ssp \ + -o conftest conftest.S 1>&AS_MESSAGE_LOG_FD 2>&AS_MESSAGE_LOG_FD; then + # Get the load address of the first PT_LOAD segment. + libc_cv_pde_load_address=$(LC_ALL=C $READELF -Wl conftest \ + | $AWK '/LOAD/ { print $3; exit 0; }') +else + AC_MSG_ERROR([${CC-cc} can not create PDE]) +fi +rm -f conftest*]) +LIBC_CONFIG_VAR([pde-load-address], [$libc_cv_pde_load_address]) + +# Get the linker command-line option to load executable at a non-zero +# load address. This is only used by glibc tests to verify that PIE and +# static PIE with non-zero load address work correctly. +LIBC_LINKER_FEATURE([-Ttext-segment=$libc_cv_pde_load_address], + [-Wl,-Ttext-segment=$libc_cv_pde_load_address], + [libc_cv_load_address_ldflag=-Wl,-Ttext-segment], + [libc_cv_load_address_ldflag=]) +LIBC_CONFIG_VAR([load-address-ldflag], [$libc_cv_load_address_ldflag]) + AC_MSG_CHECKING(if we can build programs as PIE) AC_COMPILE_IFELSE([AC_LANG_SOURCE([[#ifdef PIE_UNSUPPORTED # error PIE is not supported diff --git a/elf/Makefile b/elf/Makefile index 9cfe738919..4eaca7af67 100644 --- a/elf/Makefile +++ b/elf/Makefile @@ -1091,6 +1091,25 @@ tests-pie += \ tst-pie1 \ tst-pie2 \ # tests-pie +ifneq (,$(load-address-ldflag)) +tests += \ + tst-pie-address \ + # tests +tests-pie += \ + tst-pie-address \ + # tests-pie +LDFLAGS-tst-pie-address += $(load-address-ldflag)=$(pde-load-address) +ifeq (yes,$(enable-static-pie)) +tests += \ + tst-pie-address-static \ + # tests +tests-static += \ + tst-pie-address-static \ + # tests-static +LDFLAGS-tst-pie-address-static += \ + $(load-address-ldflag)=$(pde-load-address) +endif +endif ifeq (yes,$(have-protected-data)) tests += vismain tests-pie += vismain @@ -1937,6 +1956,7 @@ $(objpfx)tst-array5-static-cmp.out: tst-array5-static.exp \ CFLAGS-tst-pie1.c += $(pie-ccflag) CFLAGS-tst-pie2.c += $(pie-ccflag) +CFLAGS-tst-pie-address.c += $(pie-ccflag) $(objpfx)tst-piemod1.so: $(libsupport) $(objpfx)tst-pie1: $(objpfx)tst-piemod1.so diff --git a/elf/dl-reloc-static-pie.c b/elf/dl-reloc-static-pie.c index 10c23d0bf0..bfee89dfc3 100644 --- a/elf/dl-reloc-static-pie.c +++ b/elf/dl-reloc-static-pie.c @@ -37,21 +37,37 @@ _dl_relocate_static_pie (void) { struct link_map *main_map = _dl_get_dl_main_map (); - /* Figure out the run-time load address of static PIE. */ - main_map->l_addr = elf_machine_load_address (); - - /* Read our own dynamic section and fill in the info array. */ - main_map->l_ld = ((void *) main_map->l_addr + elf_machine_dynamic ()); - + /* NB: elf_machine_load_address () returns the run-time load address + of static PIE. The l_addr field contains the difference between the + link-time load address in the ELF file and the run-time load address + in memory. We must subtract the link-time load address of static PIE, + which can be non-zero, when computing the l_addr field. Since static + PIE usually doesn't have PT_PHDR segment, use p_vaddr of the PT_LOAD + segment with offset == 0 as the load address of static PIE. */ + ElfW(Addr) file_p_vaddr = 0; const ElfW(Phdr) *ph, *phdr = GL(dl_phdr); size_t phnum = GL(dl_phnum); for (ph = phdr; ph < &phdr[phnum]; ++ph) - if (ph->p_type == PT_DYNAMIC) + switch (ph->p_type) { + case PT_LOAD: + if (ph->p_offset == 0) + file_p_vaddr = ph->p_vaddr; + break; + case PT_DYNAMIC: main_map->l_ld_readonly = (ph->p_flags & PF_W) == 0; break; + default: + break; } + /* Figure out the run-time load address of static PIE. */ + ElfW(Addr) l_addr = elf_machine_load_address (); + main_map->l_addr = l_addr - file_p_vaddr; + + /* Read our own dynamic section and fill in the info array. */ + main_map->l_ld = ((void *) l_addr + elf_machine_dynamic ()); + elf_get_dynamic_info (main_map, false, true); # ifdef ELF_MACHINE_BEFORE_RTLD_RELOC diff --git a/elf/tst-pie-address-static.c b/elf/tst-pie-address-static.c new file mode 100644 index 0000000000..be2831e9d6 --- /dev/null +++ b/elf/tst-pie-address-static.c @@ -0,0 +1,19 @@ +/* Test static PIE with non-zero load address. + Copyright (C) 2024 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 + <https://www.gnu.org/licenses/>. */ + +#include "tst-pie-address.c" diff --git a/elf/tst-pie-address.c b/elf/tst-pie-address.c new file mode 100644 index 0000000000..aa1ca0a9fd --- /dev/null +++ b/elf/tst-pie-address.c @@ -0,0 +1,28 @@ +/* Test PIE with non-zero load address. + Copyright (C) 2024 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 + <https://www.gnu.org/licenses/>. */ + +#include <stdio.h> + +static int +do_test (void) +{ + printf ("Hello\n"); + return 0; +} + +#include <support/test-driver.c>
For a static PIE with non-zero load address, its PT_DYNAMIC segment entries contain the relocated values for the load address in static PIE. Since static PIE usually doesn't have PT_PHDR segment, use p_vaddr of the PT_LOAD segment with offset == 0 as the load address in static PIE and adjust the entries of PT_DYNAMIC segment in static PIE by properly setting the l_addr field for static PIE. This fixes BZ #31799. Signed-off-by: H.J. Lu <hjl.tools@gmail.com> --- configure | 74 ++++++++++++++++++++++++++++++++++++ configure.ac | 36 ++++++++++++++++++ elf/Makefile | 20 ++++++++++ elf/dl-reloc-static-pie.c | 30 +++++++++++---- elf/tst-pie-address-static.c | 19 +++++++++ elf/tst-pie-address.c | 28 ++++++++++++++ 6 files changed, 200 insertions(+), 7 deletions(-) create mode 100644 elf/tst-pie-address-static.c create mode 100644 elf/tst-pie-address.c