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Issue an error for read-only segment with dynamic IFUNC relocations

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To load an ELF binary with DT_TEXTREL tag, the dynamic linker calls
__mprotect on the read-only segment with PROT_READ|PROT_WRITE before
applying dynamic relocation.  It leads to segfault when performing
IFUNC relocations since the read-only segment has no execute permission.
This patch changes x86 linker to issue an error for read-only segment
with dynamic IFUNC relocations.  Other backends with IFUNC support
may need a similar change.

bfd/

	PR ld/18801
	* elf32-i386.c (elf_i386_size_dynamic_sections): Issue an error
	for read-only segment with dynamic IFUNC relocations.
	* elf64-x86-64.c (elf_x86_64_size_dynamic_sections): Likewise.

ld/testsuite/

	PR ld/18801
	* ld-i386/i386.exp: Run pr18801.
	* ld-x86-64/x86-64.exp: Likewise.
	* ld-i386/pr18801.d: New file.
	* ld-i386/pr18801.s: Likewise.
	* ld-x86-64/pr18801.d: Likewise.
	* ld-x86-64/pr18801.s: Likewise.
This commit is contained in:
H.J. Lu 2015-08-13 04:31:38 -07:00
parent 4ab90a7a90
commit 8efa2874ab
10 changed files with 73 additions and 0 deletions
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7
bfd/ChangeLog
View File

@ -1,3 +1,10 @@
2015-08-13 H.J. Lu <hongjiu.lu@intel.com>
PR ld/18801
* elf32-i386.c (elf_i386_size_dynamic_sections): Issue an error
for read-only segment with dynamic IFUNC relocations.
* elf64-x86-64.c (elf_x86_64_size_dynamic_sections): Likewise.
2015-08-12 Simon Dardis <simon.dardis@imgtec.com>
* elfxx-mips.c (STUB_MOVE): Change to use 'or' only.

9
bfd/elf32-i386.c
View File

@ -3152,6 +3152,15 @@ elf_i386_size_dynamic_sections (bfd *output_bfd, struct bfd_link_info *info)
if ((info->flags & DF_TEXTREL) != 0)
{
if ((elf_tdata (output_bfd)->has_gnu_symbols
& elf_gnu_symbol_ifunc) == elf_gnu_symbol_ifunc)
{
info->callbacks->einfo
(_("%P%X: read-only segment has dynamic IFUNC relocations; recompile with -fPIC\n"));
bfd_set_error (bfd_error_bad_value);
return FALSE;
}
if (!add_dynamic_entry (DT_TEXTREL, 0))
return FALSE;
}

9
bfd/elf64-x86-64.c
View File

@ -3513,6 +3513,15 @@ elf_x86_64_size_dynamic_sections (bfd *output_bfd,
if ((info->flags & DF_TEXTREL) != 0)
{
if ((elf_tdata (output_bfd)->has_gnu_symbols
& elf_gnu_symbol_ifunc) == elf_gnu_symbol_ifunc)
{
info->callbacks->einfo
(_("%P%X: read-only segment has dynamic IFUNC relocations; recompile with -fPIC\n"));
bfd_set_error (bfd_error_bad_value);
return FALSE;
}
if (!add_dynamic_entry (DT_TEXTREL, 0))
return FALSE;
}

10
ld/testsuite/ChangeLog
View File

@ -1,3 +1,13 @@
2015-08-13 H.J. Lu <hongjiu.lu@intel.com>
PR ld/18801
* ld-i386/i386.exp: Run pr18801.
* ld-x86-64/x86-64.exp: Likewise.
* ld-i386/pr18801.d: New file.
* ld-i386/pr18801.s: Likewise.
* ld-x86-64/pr18801.d: Likewise.
* ld-x86-64/pr18801.s: Likewise.
2015-08-12 Simon Dardis <simon.dardis@imgtec.com>
* ld-mips-elf/compressed-plt-1-n32-mips16.od: Update test.

1
ld/testsuite/ld-i386/i386.exp
View File

@ -309,6 +309,7 @@ run_dump_test "pr14215"
run_dump_test "pr17057"
run_dump_test "pr17935-1"
run_dump_test "pr17935-2"
run_dump_test "pr18801"
run_dump_test "pr18815"
# Add $PLT_CFLAGS if PLT is expected.

3
ld/testsuite/ld-i386/pr18801.d Normal file
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@ -0,0 +1,3 @@
#as: --32
#ld: -m elf_i386 -pie
#error: read-only segment has dynamic IFUNC relocations; recompile with -fPIC

15
ld/testsuite/ld-i386/pr18801.s Normal file
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@ -0,0 +1,15 @@
.text
.type selector, %function
foo:
movl $0, %eax
ret
selector:
mov $foo, %eax
ret
.type selector, %gnu_indirect_function
.globl _start
_start:
mov $selector, %eax
call *%eax
ret
.section .note.GNU-stack,"",@progbits

3
ld/testsuite/ld-x86-64/pr18801.d Normal file
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@ -0,0 +1,3 @@
#as: --64
#ld: -melf_x86_64 -pie
#error: read-only segment has dynamic IFUNC relocations; recompile with -fPIC

15
ld/testsuite/ld-x86-64/pr18801.s Normal file
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@ -0,0 +1,15 @@
.text
.type selector, %function
foo:
movl $0, %eax
ret
selector:
movabs $foo, %rax
ret
.type selector, %gnu_indirect_function
.globl _start
_start:
movabs $selector, %rax
call *%rax
ret
.section .note.GNU-stack,"",@progbits

1
ld/testsuite/ld-x86-64/x86-64.exp
View File

@ -325,6 +325,7 @@ run_dump_test "pr17935-1"
run_dump_test "pr17935-2"
run_dump_test "pr18160"
run_dump_test "pr18176"
run_dump_test "pr18801"
run_dump_test "pr18815"
# Add $PLT_CFLAGS if PLT is expected.