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elf: Do not run IFUNC resolvers for LD_DEBUG=unused [BZ #24214]

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This commit adds missing skip_ifunc checks to aarch64, arm, i386,
sparc, and x86_64.  A new test case ensures that IRELATIVE IFUNC
resolvers do not run in various diagnostic modes of the dynamic
loader.

Reviewed-By: Szabolcs Nagy <szabolcs.nagy@arm.com>
This commit is contained in:
Florian Weimer 2019-11-29 17:55:22 +01:00
parent 61a7c9df71
commit 4db71d2f98
9 changed files with 114 additions and 10 deletions
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16
elf/Makefile
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@ -348,6 +348,7 @@ tests-ifuncstatic := ifuncmain1static ifuncmain1picstatic \
tests-static += $(tests-ifuncstatic)
tests-internal += $(tests-ifuncstatic)
ifeq (yes,$(build-shared))
tests += tst-ifunc-fault-lazy tst-ifunc-fault-bindnow
# Note: sysdeps/x86_64/ifuncmain8.c uses ifuncmain8.
tests-internal += \
ifuncmain1 ifuncmain1pic ifuncmain1vis ifuncmain1vispic \
@ -1354,6 +1355,21 @@ $(objpfx)ifuncmain5static: $(addprefix $(objpfx),ifuncdep5.o)
$(objpfx)ifuncmain5staticpic: $(addprefix $(objpfx),ifuncdep5pic.o)
$(objpfx)ifuncmain5picstatic: $(addprefix $(objpfx),ifuncdep5pic.o)
LDFLAGS-tst-ifunc-fault-lazy = -Wl,-z,lazy
LDFLAGS-tst-ifunc-fault-bindnow = -Wl,-z,now
define tst-ifunc-fault-script
( $(objpfx)ld.so --verify --library-path $(objpfx) $^ \
&& LD_TRACE_LOADED_OBJECTS=1 $(objpfx)ld.so --library-path $(objpfx) $^ \
&& LD_TRACE_LOADED_OBJECTS=1 LD_DEBUG=unused \
$(objpfx)ld.so --library-path $(objpfx) $^ \
) > $@; $(evaluate-test)
endef
$(objpfx)tst-ifunc-fault-lazy.out: $(objpfx)tst-ifunc-fault-lazy $(objpfx)ld.so
$(tst-ifunc-fault-script)
$(objpfx)tst-ifunc-fault-bindnow.out: $(objpfx)tst-ifunc-fault-bindnow \
$(objpfx)ld.so
$(tst-ifunc-fault-script)
$(objpfx)tst-unique1: $(libdl)
$(objpfx)tst-unique1.out: $(objpfx)tst-unique1mod1.so \
$(objpfx)tst-unique1mod2.so

21
elf/tst-ifunc-fault-bindnow.c Normal file
View File

@ -0,0 +1,21 @@
/* Program with local IFUNC resolver which crashes. BIND_NOW variant.
Copyright (C) 2019 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/>. */
/* The code is the same as the lazy variant. It is just linked
differently. */
#include "tst-ifunc-fault-lazy.c"

57
elf/tst-ifunc-fault-lazy.c Normal file
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@ -0,0 +1,57 @@
/* Program with local IFUNC resolver which crashes, for testing bug 24214.
Copyright (C) 2019 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/>. */
/* The construct below is expected to produce an IRELATIVE relocation
with an IFUNC resolver that crashes. ldd should not performs such
relocations. */
#include <config.h>
#ifdef HAVE_GCC_IFUNC
# include <stddef.h>
static void
implementation (void)
{
/* Produce a crash, without depending on any relocations. */
volatile char *volatile p = NULL;
*p = 0;
}
static __typeof__ (implementation) *
resolver (void)
{
/* Produce a crash, without depending on any relocations. */
volatile char *volatile p = NULL;
*p = 0;
return implementation;
}
static void magic (void) __attribute__ ((ifunc ("resolver")));
void (*magic_ptr) (void) = magic;
#endif /* HAVE_GCC_IFUNC */
/* The program is expected not to run. */
int
main (void)
{
return 1;
}

3
sysdeps/aarch64/dl-machine.h
View File

@ -358,7 +358,8 @@ elf_machine_rela (struct link_map *map, const ElfW(Rela) *reloc,
case AARCH64_R(IRELATIVE):
value = map->l_addr + reloc->r_addend;
value = elf_ifunc_invoke (value);
if (__glibc_likely (!skip_ifunc))
value = elf_ifunc_invoke (value);
*reloc_addr = value;
break;

6
sysdeps/arm/dl-machine.h
View File

@ -522,7 +522,8 @@ elf_machine_rel (struct link_map *map, const Elf32_Rel *reloc,
break;
case R_ARM_IRELATIVE:
value = map->l_addr + *reloc_addr;
value = ((Elf32_Addr (*) (int)) value) (GLRO(dl_hwcap));
if (__glibc_likely (!skip_ifunc))
value = ((Elf32_Addr (*) (int)) value) (GLRO(dl_hwcap));
*reloc_addr = value;
break;
#endif
@ -614,7 +615,8 @@ elf_machine_rela (struct link_map *map, const Elf32_Rela *reloc,
break;
case R_ARM_IRELATIVE:
value = map->l_addr + reloc->r_addend;
value = ((Elf32_Addr (*) (int)) value) (GLRO(dl_hwcap));
if (__glibc_likely (!skip_ifunc))
value = ((Elf32_Addr (*) (int)) value) (GLRO(dl_hwcap));
*reloc_addr = value;
break;
#endif

6
sysdeps/i386/dl-machine.h
View File

@ -480,7 +480,8 @@ elf_machine_rel (struct link_map *map, const Elf32_Rel *reloc,
break;
case R_386_IRELATIVE:
value = map->l_addr + *reloc_addr;
value = ((Elf32_Addr (*) (void)) value) ();
if (__glibc_likely (!skip_ifunc))
value = ((Elf32_Addr (*) (void)) value) ();
*reloc_addr = value;
break;
default:
@ -627,7 +628,8 @@ elf_machine_rela (struct link_map *map, const Elf32_Rela *reloc,
# endif /* !RESOLVE_CONFLICT_FIND_MAP */
case R_386_IRELATIVE:
value = map->l_addr + reloc->r_addend;
value = ((Elf32_Addr (*) (void)) value) ();
if (__glibc_likely (!skip_ifunc))
value = ((Elf32_Addr (*) (void)) value) ();
*reloc_addr = value;
break;
default:

6
sysdeps/sparc/sparc32/dl-machine.h
View File

@ -425,11 +425,13 @@ elf_machine_rela (struct link_map *map, const Elf32_Rela *reloc,
*reloc_addr = value;
break;
case R_SPARC_IRELATIVE:
value = ((Elf32_Addr (*) (int)) value) (GLRO(dl_hwcap));
if (__glibc_likely (!skip_ifunc))
value = ((Elf32_Addr (*) (int)) value) (GLRO(dl_hwcap));
*reloc_addr = value;
break;
case R_SPARC_JMP_IREL:
value = ((Elf32_Addr (*) (int)) value) (GLRO(dl_hwcap));
if (__glibc_likely (!skip_ifunc))
value = ((Elf32_Addr (*) (int)) value) (GLRO(dl_hwcap));
/* Fall thru */
case R_SPARC_JMP_SLOT:
{

6
sysdeps/sparc/sparc64/dl-machine.h
View File

@ -450,11 +450,13 @@ elf_machine_rela (struct link_map *map, const Elf64_Rela *reloc,
*reloc_addr = value;
break;
case R_SPARC_IRELATIVE:
value = ((Elf64_Addr (*) (int)) value) (GLRO(dl_hwcap));
if (__glibc_likely (!skip_ifunc))
value = ((Elf64_Addr (*) (int)) value) (GLRO(dl_hwcap));
*reloc_addr = value;
break;
case R_SPARC_JMP_IREL:
value = ((Elf64_Addr (*) (int)) value) (GLRO(dl_hwcap));
if (__glibc_likely (!skip_ifunc))
value = ((Elf64_Addr (*) (int)) value) (GLRO(dl_hwcap));
/* 'high' is always zero, for large PLT entries the linker
emits an R_SPARC_IRELATIVE. */
#ifdef RESOLVE_CONFLICT_FIND_MAP

3
sysdeps/x86_64/dl-machine.h
View File

@ -512,7 +512,8 @@ elf_machine_rela (struct link_map *map, const ElfW(Rela) *reloc,
# endif
case R_X86_64_IRELATIVE:
value = map->l_addr + reloc->r_addend;
value = ((ElfW(Addr) (*) (void)) value) ();
if (__glibc_likely (!skip_ifunc))
value = ((ElfW(Addr) (*) (void)) value) ();
*reloc_addr = value;
break;
default: