From 4ec0995016801cc5d5cf13baf6e10163861e6852 Mon Sep 17 00:00:00 2001 From: "H.J. Lu" Date: Mon, 14 May 2018 03:55:37 -0700 Subject: [PATCH] x86; Allow IFUNC pointer defined in PDE If IFUNC symbol is defined in position-dependent executable, we should change it to the normal function and set its address to its PLT entry which should be resolved by R_*_IRELATIVE at run-time. All external references should be resolved to its PLT in executable. bfd/ PR ld/23169 * elf-ifunc.c (_bfd_elf_allocate_ifunc_dyn_relocs): Don't issue an error on IFUNC pointer defined in PDE. * elf32-i386.c (elf_i386_finish_dynamic_symbol): Call _bfd_x86_elf_link_fixup_ifunc_symbol. * elf64-x86-64.c (elf_x86_64_finish_dynamic_symbol): Likewise. * elfxx-x86.c (_bfd_x86_elf_link_fixup_ifunc_symbol): New function. * elfxx-x86.h (_bfd_x86_elf_link_fixup_ifunc_symbol): New. ld/ PR ld/23169 * testsuite/ld-ifunc/ifunc-9-i386.d: New file. * testsuite/ld-ifunc/ifunc-9-x86-64.d: Likewise. * testsuite/ld-ifunc/pr23169a.c: Likewise. * testsuite/ld-ifunc/pr23169a.rd: Likewise. * testsuite/ld-ifunc/pr23169b.c: Likewise. * testsuite/ld-ifunc/pr23169b.c: Likewise. * testsuite/ld-ifunc/pr23169c.rd: Likewise. * testsuite/ld-ifunc/pr23169c.rd: Likewise. * testsuite/ld-ifunc/ifunc-9-x86.d: Removed. * testsuite/ld-ifunc/ifunc.exp: Run PR ld/23169 tests. --- bfd/ChangeLog | 12 ++++ bfd/elf-ifunc.c | 9 ++- bfd/elf32-i386.c | 2 + bfd/elf64-x86-64.c | 2 + bfd/elfxx-x86.c | 46 ++++++++++++ bfd/elfxx-x86.h | 4 ++ ld/ChangeLog | 14 ++++ ld/testsuite/ld-ifunc/ifunc-9-i386.d | 9 +++ ld/testsuite/ld-ifunc/ifunc-9-x86-64.d | 9 +++ ld/testsuite/ld-ifunc/ifunc-9-x86.d | 3 - ld/testsuite/ld-ifunc/ifunc.exp | 124 +++++++++++++++++++++++++++++++++ ld/testsuite/ld-ifunc/pr23169a.c | 9 +++ ld/testsuite/ld-ifunc/pr23169a.rd | 6 ++ ld/testsuite/ld-ifunc/pr23169b.c | 23 ++++++ ld/testsuite/ld-ifunc/pr23169b.rd | 3 + ld/testsuite/ld-ifunc/pr23169c.c | 13 ++++ ld/testsuite/ld-ifunc/pr23169c.rd | 6 ++ 17 files changed, 290 insertions(+), 4 deletions(-) create mode 100644 ld/testsuite/ld-ifunc/ifunc-9-i386.d create mode 100644 ld/testsuite/ld-ifunc/ifunc-9-x86-64.d delete mode 100644 ld/testsuite/ld-ifunc/ifunc-9-x86.d create mode 100644 ld/testsuite/ld-ifunc/pr23169a.c create mode 100644 ld/testsuite/ld-ifunc/pr23169a.rd create mode 100644 ld/testsuite/ld-ifunc/pr23169b.c create mode 100644 ld/testsuite/ld-ifunc/pr23169b.rd create mode 100644 ld/testsuite/ld-ifunc/pr23169c.c create mode 100644 ld/testsuite/ld-ifunc/pr23169c.rd diff --git a/bfd/ChangeLog b/bfd/ChangeLog index 10b9679..f8138a1 100644 --- a/bfd/ChangeLog +++ b/bfd/ChangeLog @@ -1,5 +1,17 @@ 2018-05-14 H.J. Lu + PR ld/23169 + * elf-ifunc.c (_bfd_elf_allocate_ifunc_dyn_relocs): Don't issue + an error on IFUNC pointer defined in PDE. + * elf32-i386.c (elf_i386_finish_dynamic_symbol): Call + _bfd_x86_elf_link_fixup_ifunc_symbol. + * elf64-x86-64.c (elf_x86_64_finish_dynamic_symbol): Likewise. + * elfxx-x86.c (_bfd_x86_elf_link_fixup_ifunc_symbol): New + function. + * elfxx-x86.h (_bfd_x86_elf_link_fixup_ifunc_symbol): New. + +2018-05-14 H.J. Lu + PR ld/23162 * elfxx-x86.c (elf_x86_linker_defined): New function. (_bfd_x86_elf_link_check_relocs): Use it to mark __bss_start, diff --git a/bfd/elf-ifunc.c b/bfd/elf-ifunc.c index 5716ab3..b8a3632 100644 --- a/bfd/elf-ifunc.c +++ b/bfd/elf-ifunc.c @@ -131,8 +131,15 @@ _bfd_elf_allocate_ifunc_dyn_relocs (struct bfd_link_info *info, the resolved function may be used. But in non-PIC executable, the address of its .plt slot may be used. Pointer equality may not work correctly. PIE or non-PLT reference should be used if - pointer equality is required here. */ + pointer equality is required here. + + If STT_GNU_IFUNC symbol is defined in position-dependent executable, + backend should change it to the normal function and set its address + to its PLT entry which should be resolved by R_*_IRELATIVE at + run-time. All external references should be resolved to its PLT in + executable. */ if (!need_dynreloc + && !(bfd_link_pde (info) && h->def_regular) && (h->dynindx != -1 || info->export_dynamic) && h->pointer_equality_needed) diff --git a/bfd/elf32-i386.c b/bfd/elf32-i386.c index c1c4ed0..580a591 100644 --- a/bfd/elf32-i386.c +++ b/bfd/elf32-i386.c @@ -3805,6 +3805,8 @@ elf_i386_finish_dynamic_symbol (bfd *output_bfd, sym->st_value = 0; } + _bfd_x86_elf_link_fixup_ifunc_symbol (info, htab, h, sym); + /* Don't generate dynamic GOT relocation against undefined weak symbol in executable. */ if (h->got.offset != (bfd_vma) -1 diff --git a/bfd/elf64-x86-64.c b/bfd/elf64-x86-64.c index a0ebd2c..e5a4dbc 100644 --- a/bfd/elf64-x86-64.c +++ b/bfd/elf64-x86-64.c @@ -4147,6 +4147,8 @@ elf_x86_64_finish_dynamic_symbol (bfd *output_bfd, sym->st_value = 0; } + _bfd_x86_elf_link_fixup_ifunc_symbol (info, htab, h, sym); + /* Don't generate dynamic GOT relocation against undefined weak symbol in executable. */ if (h->got.offset != (bfd_vma) -1 diff --git a/bfd/elfxx-x86.c b/bfd/elfxx-x86.c index 6c1f4c3..936b4c6 100644 --- a/bfd/elfxx-x86.c +++ b/bfd/elfxx-x86.c @@ -1730,6 +1730,52 @@ _bfd_x86_elf_fixup_symbol (struct bfd_link_info *info, return TRUE; } +/* Change the STT_GNU_IFUNC symbol defined in position-dependent + executable into the normal function symbol and set its address + to its PLT entry, which should be resolved by R_*_IRELATIVE at + run-time. */ + +void +_bfd_x86_elf_link_fixup_ifunc_symbol (struct bfd_link_info *info, + struct elf_x86_link_hash_table *htab, + struct elf_link_hash_entry *h, + Elf_Internal_Sym *sym) +{ + if (bfd_link_pde (info) + && h->def_regular + && h->dynindx != -1 + && h->plt.offset != (bfd_vma) -1 + && h->type == STT_GNU_IFUNC + && h->pointer_equality_needed) + { + asection *plt_s; + bfd_vma plt_offset; + bfd *output_bfd = info->output_bfd; + + if (htab->plt_second) + { + struct elf_x86_link_hash_entry *eh + = (struct elf_x86_link_hash_entry *) h; + + plt_s = htab->plt_second; + plt_offset = eh->plt_second.offset; + } + else + { + plt_s = htab->elf.splt; + plt_offset = h->plt.offset; + } + + sym->st_size = 0; + sym->st_info = ELF_ST_INFO (ELF_ST_BIND (sym->st_info), STT_FUNC); + sym->st_shndx + = _bfd_elf_section_from_bfd_section (output_bfd, + plt_s->output_section); + sym->st_value = (plt_s->output_section->vma + + plt_s->output_offset + plt_offset); + } +} + /* Return TRUE if symbol should be hashed in the `.gnu.hash' section. */ bfd_boolean diff --git a/bfd/elfxx-x86.h b/bfd/elfxx-x86.h index efa835e..8f67c23 100644 --- a/bfd/elfxx-x86.h +++ b/bfd/elfxx-x86.h @@ -674,6 +674,10 @@ extern bfd_boolean _bfd_x86_elf_merge_gnu_properties extern bfd * _bfd_x86_elf_link_setup_gnu_properties (struct bfd_link_info *, struct elf_x86_init_table *); +extern void _bfd_x86_elf_link_fixup_ifunc_symbol + (struct bfd_link_info *, struct elf_x86_link_hash_table *, + struct elf_link_hash_entry *, Elf_Internal_Sym *sym); + #define bfd_elf64_mkobject \ _bfd_x86_elf_mkobject #define bfd_elf32_mkobject \ diff --git a/ld/ChangeLog b/ld/ChangeLog index 178ca68..fbc4d59 100644 --- a/ld/ChangeLog +++ b/ld/ChangeLog @@ -1,5 +1,19 @@ 2018-05-14 H.J. Lu + PR ld/23169 + * testsuite/ld-ifunc/ifunc-9-i386.d: New file. + * testsuite/ld-ifunc/ifunc-9-x86-64.d: Likewise. + * testsuite/ld-ifunc/pr23169a.c: Likewise. + * testsuite/ld-ifunc/pr23169a.rd: Likewise. + * testsuite/ld-ifunc/pr23169b.c: Likewise. + * testsuite/ld-ifunc/pr23169b.c: Likewise. + * testsuite/ld-ifunc/pr23169c.rd: Likewise. + * testsuite/ld-ifunc/pr23169c.rd: Likewise. + * testsuite/ld-ifunc/ifunc-9-x86.d: Removed. + * testsuite/ld-ifunc/ifunc.exp: Run PR ld/23169 tests. + +2018-05-14 H.J. Lu + PR ld/23162 * testsuite/ld-elf/pr23162.map: New file. * testsuite/ld-elf/pr23162.rd: Likewise. diff --git a/ld/testsuite/ld-ifunc/ifunc-9-i386.d b/ld/testsuite/ld-ifunc/ifunc-9-i386.d new file mode 100644 index 0000000..754ee2d --- /dev/null +++ b/ld/testsuite/ld-ifunc/ifunc-9-i386.d @@ -0,0 +1,9 @@ +#source: ifunc-9-x86.s +#as: --32 +#ld: -m elf_i386 --export-dynamic +#readelf: -r --wide +#target: x86_64-*-* i?86-*-* + +Relocation section '.rel.plt' at .* +[ ]+Offset[ ]+Info[ ]+Type[ ]+.* +[0-9a-f]+[ ]+[0-9a-f]+[ ]+R_386_IRELATIVE[ ]* diff --git a/ld/testsuite/ld-ifunc/ifunc-9-x86-64.d b/ld/testsuite/ld-ifunc/ifunc-9-x86-64.d new file mode 100644 index 0000000..85c3a69 --- /dev/null +++ b/ld/testsuite/ld-ifunc/ifunc-9-x86-64.d @@ -0,0 +1,9 @@ +#source: ifunc-9-x86.s +#as: --64 +#ld: -melf_x86_64 --export-dynamic +#readelf: -r --wide +#target: x86_64-*-* + +Relocation section '.rela.plt' at .* +[ ]+Offset[ ]+Info[ ]+Type[ ]+.* +[0-9a-f]+[ ]+[0-9a-f]+[ ]+R_X86_64_IRELATIVE[ ]+[0-9a-f]* diff --git a/ld/testsuite/ld-ifunc/ifunc-9-x86.d b/ld/testsuite/ld-ifunc/ifunc-9-x86.d deleted file mode 100644 index 7390dd1..0000000 --- a/ld/testsuite/ld-ifunc/ifunc-9-x86.d +++ /dev/null @@ -1,3 +0,0 @@ -#ld: --export-dynamic -#error: .*dynamic STT_GNU_IFUNC symbol `foo' with pointer equality in `.*.o' can not be used when making an executable; recompile with -fPIE and relink with -pie -#target: x86_64-*-* i?86-*-* diff --git a/ld/testsuite/ld-ifunc/ifunc.exp b/ld/testsuite/ld-ifunc/ifunc.exp index d9cc381..9f4aa73 100644 --- a/ld/testsuite/ld-ifunc/ifunc.exp +++ b/ld/testsuite/ld-ifunc/ifunc.exp @@ -581,6 +581,76 @@ run_cc_link_tests [list \ {} \ "libpr18841cn.so" \ ] \ + [list \ + "Build libpr23169a.so" \ + "-shared" \ + "-fPIC -O2 -g" \ + { pr23169a.c } \ + {} \ + "libpr23169a.so" \ + ] \ + [list \ + "Build libpr23169b.so" \ + "-shared -Wl,-z,now" \ + "-fPIC -O2 -g" \ + { pr23169a.c } \ + {} \ + "libpr23169b.so" \ + ] \ + [list \ + "Build pr23169a" \ + "$NOPIE_LDFLAGS -Wl,--no-as-needed tmpdir/libpr23169a.so" \ + "$NOPIE_CFLAGS -O2 -g" \ + { pr23169b.c pr23169c.c } \ + {{readelf {--dyn-syms} pr23169a.rd} \ + {readelf {-r -W} pr23169b.rd}} \ + "pr23169a" \ + ] \ + [list \ + "Build pr23169b" \ + "-pie -Wl,--no-as-needed tmpdir/libpr23169a.so" \ + "-fPIE -O2 -g" \ + { pr23169b.c pr23169c.c } \ + {{readelf {--dyn-syms} pr23169c.rd} \ + {readelf {-r -W} pr23169b.rd}} \ + "pr23169b" \ + ] \ + [list \ + "Build pr23169c" \ + "$NOPIE_LDFLAGS -Wl,--no-as-needed tmpdir/libpr23169a.so" \ + "-fPIE -O2 -g" \ + { pr23169b.c pr23169c.c } \ + {{readelf {--dyn-syms} pr23169c.rd} \ + {readelf {-r -W} pr23169b.rd}} \ + "pr23169c" \ + ] \ + [list \ + "Build pr23169d" \ + "$NOPIE_LDFLAGS -Wl,--no-as-needed,-z,now tmpdir/libpr23169b.so" \ + "$NOPIE_CFLAGS -O2 -g" \ + { pr23169b.c pr23169c.c } \ + {{readelf {--dyn-syms} pr23169a.rd} \ + {readelf {-r -W} pr23169b.rd}} \ + "pr23169d" \ + ] \ + [list \ + "Build pr23169e" \ + "-pie -Wl,--no-as-needed,-z,now tmpdir/libpr23169b.so" \ + "-fPIE -O2 -g" \ + { pr23169b.c pr23169c.c } \ + {{readelf {--dyn-syms} pr23169c.rd} \ + {readelf {-r -W} pr23169b.rd}} \ + "pr23169e" \ + ] \ + [list \ + "Build pr23169f" \ + "$NOPIE_LDFLAGS -Wl,--no-as-needed,-z,now tmpdir/libpr23169b.so" \ + "-fPIE -O2 -g" \ + { pr23169b.c pr23169c.c } \ + {{readelf {--dyn-syms} pr23169c.rd} \ + {readelf {-r -W} pr23169b.rd}} \ + "pr23169f" \ + ] \ ] run_ld_link_exec_tests [list \ @@ -632,4 +702,58 @@ run_ld_link_exec_tests [list \ "pr18841cn" \ "pr18841.out" \ ] \ + [list \ + "Run pr23169a" \ + "$NOPIE_LDFLAGS -Wl,--no-as-needed tmpdir/libpr23169a.so" \ + "" \ + { pr23169b.c pr23169c.c } \ + "pr23169a" \ + "pass.out" \ + "$NOPIE_CFLAGS -O2 -g" \ + ] \ + [list \ + "Run pr23169b" \ + "-pie -Wl,--no-as-needed tmpdir/libpr23169a.so" \ + "" \ + { pr23169b.c pr23169c.c } \ + "pr23169b" \ + "pass.out" \ + "-fPIE -O2 -g" \ + ] \ + [list \ + "Run pr23169c" \ + "$NOPIE_LDFLAGS -Wl,--no-as-needed tmpdir/libpr23169a.so" \ + "" \ + { pr23169b.c pr23169c.c } \ + "pr23169c" \ + "pass.out" \ + "-fPIE -O2 -g" \ + ] \ + [list \ + "Run pr23169d" \ + "$NOPIE_LDFLAGS -Wl,--no-as-needed,-z,now tmpdir/libpr23169b.so" \ + "" \ + { pr23169b.c pr23169c.c } \ + "pr23169d" \ + "pass.out" \ + "$NOPIE_CFLAGS -O2 -g" \ + ] \ + [list \ + "Run pr23169e" \ + "-pie -Wl,--no-as-needed,-z,now tmpdir/libpr23169b.so" \ + "" \ + { pr23169b.c pr23169c.c } \ + "pr23169e" \ + "pass.out" \ + "-fPIE -O2 -g" \ + ] \ + [list \ + "Run pr23169f" \ + "$NOPIE_LDFLAGS -Wl,--no-as-needed,-z,now tmpdir/libpr23169b.so" \ + "" \ + { pr23169b.c pr23169c.c } \ + "pr23169f" \ + "pass.out" \ + "-fPIE -O2 -g" \ + ] \ ] diff --git a/ld/testsuite/ld-ifunc/pr23169a.c b/ld/testsuite/ld-ifunc/pr23169a.c new file mode 100644 index 0000000..02bf220 --- /dev/null +++ b/ld/testsuite/ld-ifunc/pr23169a.c @@ -0,0 +1,9 @@ +int (*func_p) (void); +extern int func (void); + +void +foo (void) +{ + if (func_p != &func || func_p () != 0xbadbeef) + __builtin_abort (); +} diff --git a/ld/testsuite/ld-ifunc/pr23169a.rd b/ld/testsuite/ld-ifunc/pr23169a.rd new file mode 100644 index 0000000..ca04d8f --- /dev/null +++ b/ld/testsuite/ld-ifunc/pr23169a.rd @@ -0,0 +1,6 @@ + +Symbol table '\.dynsym' contains [0-9]+ entries: + +Num: +Value +Size Type +Bind +Vis +Ndx Name +#... + +[0-9]+: +[a-f0-9]+ +0 +FUNC +GLOBAL +DEFAULT +[0-9]+ +func +#... diff --git a/ld/testsuite/ld-ifunc/pr23169b.c b/ld/testsuite/ld-ifunc/pr23169b.c new file mode 100644 index 0000000..99790d4 --- /dev/null +++ b/ld/testsuite/ld-ifunc/pr23169b.c @@ -0,0 +1,23 @@ +#include + +extern int (*func_p) (void); +extern int func (void); +extern void foo (void); + + +void +bar (void) +{ + if (func_p != &func || func_p () != 0xbadbeef) + __builtin_abort (); +} + +int +main () +{ + func_p = &func; + foo (); + bar (); + printf ("PASS\n"); + return 0; +} diff --git a/ld/testsuite/ld-ifunc/pr23169b.rd b/ld/testsuite/ld-ifunc/pr23169b.rd new file mode 100644 index 0000000..d57a793 --- /dev/null +++ b/ld/testsuite/ld-ifunc/pr23169b.rd @@ -0,0 +1,3 @@ +#failif +[a-f0-9]+ +[0-9a-f]+ +R_.*_* +[a-f0-9]+ +func(| \+ 0) +... diff --git a/ld/testsuite/ld-ifunc/pr23169c.c b/ld/testsuite/ld-ifunc/pr23169c.c new file mode 100644 index 0000000..b530108 --- /dev/null +++ b/ld/testsuite/ld-ifunc/pr23169c.c @@ -0,0 +1,13 @@ +static int +ifunc (void) +{ + return 0xbadbeef; +} + +void func(void) __attribute__((ifunc("resolve_func"))); + +static void * +resolve_func (void) +{ + return ifunc; +} diff --git a/ld/testsuite/ld-ifunc/pr23169c.rd b/ld/testsuite/ld-ifunc/pr23169c.rd new file mode 100644 index 0000000..1c4ba8a --- /dev/null +++ b/ld/testsuite/ld-ifunc/pr23169c.rd @@ -0,0 +1,6 @@ + +Symbol table '\.dynsym' contains [0-9]+ entries: + +Num: +Value +Size Type +Bind +Vis +Ndx Name +#... + +[0-9]+: +[a-f0-9]+ +[0-9]+ +IFUNC +GLOBAL +DEFAULT +[0-9]+ +func +#... -- 2.7.4