diff options
| -rw-r--r-- | ChangeLog | 15 | ||||
| -rw-r--r-- | config.make.in | 1 | ||||
| -rwxr-xr-x | configure | 47 | ||||
| -rw-r--r-- | configure.ac | 35 | ||||
| -rw-r--r-- | elf/Makefile | 4 | ||||
| -rw-r--r-- | elf/dl-reloc.c | 20 | ||||
| -rw-r--r-- | elf/tst-ifunc-textrel.c | 45 |
7 files changed, 155 insertions, 12 deletions
@@ -1,3 +1,18 @@ +2018-09-25 Adam J. Richte <adam_richter2004@yahoo.com> + Adhemerval Zanella <adhemerval.zanella@linaro.org> + Fangrui Song <maskray@google.com> + + [BZ #20480] + * config.make.in (have-textrel_ifunc): New define. + * configure.ac: Add check if linker supports textrel relocation with + ifunc. + * elf/Makefile [have-textrel_ifunc == yes] (ifunc-pie-tests): Add + tst-ifunc-textrel. + (CFLAGS-tst-ifunc-textrel.c): New rule. + * elf/dl-reloc.c (_dl_relocate_object): Use all required flags on + DT_TEXTREL segments, not only PROT_READ and PROT_WRITE. + * elf/tst-ifunc-textrel.c: New file. + 2018-09-25 Joseph Myers <joseph@codesourcery.com> * sysdeps/unix/sysv/linux/sys/procfs.h: Include diff --git a/config.make.in b/config.make.in index a6fe48d..f46bfc2 100644 --- a/config.make.in +++ b/config.make.in @@ -75,6 +75,7 @@ use-default-link = @use_default_link@ output-format = @libc_cv_output_format@ have-cxx-thread_local = @libc_cv_cxx_thread_local@ have-loop-to-function = @libc_cv_cc_loop_to_function@ +have-textrel_ifunc = @libc_cv_textrel_ifunc@ multi-arch = @multi_arch@ @@ -664,6 +664,7 @@ INSTALL_PROGRAM sysnames submachine multi_arch +libc_cv_textrel_ifunc no_stack_protector stack_protector libc_cv_ssp @@ -4052,6 +4053,52 @@ fi { $as_echo "$as_me:${as_lineno-$LINENO}: result: $libc_cv_gcc_indirect_function" >&5 $as_echo "$libc_cv_gcc_indirect_function" >&6; } +# Check if linker supports textrel relocation with ifunc (used on elf/tests). +# Note that it relies on libc_cv_ld_gnu_indirect_function test above. +{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether the linker supports textrels along with ifunc" >&5 +$as_echo_n "checking whether the linker supports textrels along with ifunc... " >&6; } +if ${libc_cv_textrel_ifunc+:} false; then : + $as_echo_n "(cached) " >&6 +else + cat > conftest.S <<EOF +.type foo,%gnu_indirect_function +foo: +.globl _start +_start: +.globl __start +__start: +.data +#ifdef _LP64 +.quad foo +#else +.long foo +#endif +.text +.globl address +address: +#ifdef _LP64 +.quad address +#else +.long address +#endif +EOF +libc_cv_textrel_ifunc=no +if test $libc_cv_ld_gnu_indirect_function = yes; then + if { ac_try='${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS -nostartfiles -nostdlib $no_ssp -pie -o conftest conftest.S' + { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5 + (eval $ac_try) 2>&5 + ac_status=$? + $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5 + test $ac_status = 0; }; }; then + libc_cv_textrel_ifunc=yes + fi +fi +rm -f conftest* +fi +{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $libc_cv_textrel_ifunc" >&5 +$as_echo "$libc_cv_textrel_ifunc" >&6; } + + # Check if gcc warns about alias for function with incompatible types. { $as_echo "$as_me:${as_lineno-$LINENO}: checking if compiler warns about alias for function with incompatible types" >&5 $as_echo_n "checking if compiler warns about alias for function with incompatible types... " >&6; } diff --git a/configure.ac b/configure.ac index 8045d44..e983fd8 100644 --- a/configure.ac +++ b/configure.ac @@ -671,6 +671,41 @@ if ${CC-cc} -c conftest.c -o conftest.o 1>&AS_MESSAGE_LOG_FD \ fi rm -f conftest*]) +# Check if linker supports textrel relocation with ifunc (used on elf/tests). +# Note that it relies on libc_cv_ld_gnu_indirect_function test above. +AC_CACHE_CHECK([whether the linker supports textrels along with ifunc], + libc_cv_textrel_ifunc, [dnl +cat > conftest.S <<EOF +.type foo,%gnu_indirect_function +foo: +.globl _start +_start: +.globl __start +__start: +.data +#ifdef _LP64 +.quad foo +#else +.long foo +#endif +.text +.globl address +address: +#ifdef _LP64 +.quad address +#else +.long address +#endif +EOF +libc_cv_textrel_ifunc=no +if test $libc_cv_ld_gnu_indirect_function = yes; then + if AC_TRY_COMMAND(${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS -nostartfiles -nostdlib $no_ssp -pie -o conftest conftest.S); then + libc_cv_textrel_ifunc=yes + fi +fi +rm -f conftest*]) +AC_SUBST(libc_cv_textrel_ifunc) + # Check if gcc warns about alias for function with incompatible types. AC_CACHE_CHECK([if compiler warns about alias for function with incompatible types], libc_cv_gcc_incompatible_alias, [dnl diff --git a/elf/Makefile b/elf/Makefile index 4a4ca84..037f681 100644 --- a/elf/Makefile +++ b/elf/Makefile @@ -340,6 +340,9 @@ test-internal-extras += $(ifunc-test-modules) ifeq (yes,$(have-fpie)) ifunc-pie-tests = ifuncmain1pie ifuncmain1vispie ifuncmain1staticpie \ ifuncmain5pie ifuncmain6pie ifuncmain7pie +ifeq (yes,$(have-textrel_ifunc)) +ifunc-pie-tests += tst-ifunc-textrel +endif tests-internal += $(ifunc-pie-tests) tests-pie += $(ifunc-pie-tests) endif @@ -1269,6 +1272,7 @@ CFLAGS-ifuncmain1staticpie.c += $(pie-ccflag) CFLAGS-ifuncmain5pie.c += $(pie-ccflag) CFLAGS-ifuncmain6pie.c += $(pie-ccflag) CFLAGS-ifuncmain7pie.c += $(pie-ccflag) +CFLAGS-tst-ifunc-textrel.c += $(pic-ccflag) $(objpfx)ifuncmain1pie: $(objpfx)ifuncmod1.so $(objpfx)ifuncmain1staticpie: $(objpfx)ifuncdep1pic.o diff --git a/elf/dl-reloc.c b/elf/dl-reloc.c index 053916e..164f4ef 100644 --- a/elf/dl-reloc.c +++ b/elf/dl-reloc.c @@ -200,17 +200,6 @@ _dl_relocate_object (struct link_map *l, struct r_scope_elem *scope[], newp->start = PTR_ALIGN_DOWN (ph->p_vaddr, GLRO(dl_pagesize)) + (caddr_t) l->l_addr; - if (__mprotect (newp->start, newp->len, PROT_READ|PROT_WRITE) < 0) - { - errstring = N_("cannot make segment writable for relocation"); - call_error: - _dl_signal_error (errno, l->l_name, NULL, errstring); - } - -#if (PF_R | PF_W | PF_X) == 7 && (PROT_READ | PROT_WRITE | PROT_EXEC) == 7 - newp->prot = (PF_TO_PROT - >> ((ph->p_flags & (PF_R | PF_W | PF_X)) * 4)) & 0xf; -#else newp->prot = 0; if (ph->p_flags & PF_R) newp->prot |= PROT_READ; @@ -218,7 +207,14 @@ _dl_relocate_object (struct link_map *l, struct r_scope_elem *scope[], newp->prot |= PROT_WRITE; if (ph->p_flags & PF_X) newp->prot |= PROT_EXEC; -#endif + + if (__mprotect (newp->start, newp->len, newp->prot|PROT_WRITE) < 0) + { + errstring = N_("cannot make segment writable for relocation"); + call_error: + _dl_signal_error (errno, l->l_name, NULL, errstring); + } + newp->next = textrels; textrels = newp; } diff --git a/elf/tst-ifunc-textrel.c b/elf/tst-ifunc-textrel.c new file mode 100644 index 0000000..d34c4db --- /dev/null +++ b/elf/tst-ifunc-textrel.c @@ -0,0 +1,45 @@ +/* Check DT_TEXTREL/DF_TEXTREL support with ifunc. + Copyright (C) 2018 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + <http://www.gnu.org/licenses/>. */ + +#include <stdint.h> + +/* Force a text relocation in the object. */ +static const uintptr_t +address __attribute__((section(".text"))) = (uintptr_t) &address; + +static uintptr_t +foo_impl (void) +{ + return address; +} + +void * +__attribute__((noinline)) +foo (void) +{ + return (void*) foo_impl; +} +__asm__ (".type foo, %gnu_indirect_function"); + +static int +do_test (void) +{ + return (uintptr_t) foo () != 0 ? 0 : 1; +} + +#include <support/test-driver.c> |