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i386: Use _dl_runtime_[resolve|profile]_shstk for SHSTK [BZ #23716] 

When elf_machine_runtime_setup is called to set up resolver, it should
use _dl_runtime_resolve_shstk or _dl_runtime_profile_shstk if SHSTK is
enabled by kernel.

Tested on i686 with and without --enable-cet as well as on CET emulator
with --enable-cet.

	[BZ #23716]
	* sysdeps/i386/dl-cet.c: Removed.
	* sysdeps/i386/dl-machine.h (_dl_runtime_resolve_shstk): New
	prototype.
	(_dl_runtime_profile_shstk): Likewise.
	(elf_machine_runtime_setup): Use _dl_runtime_profile_shstk or
	_dl_runtime_resolve_shstk if SHSTK is enabled by kernel.

Signed-off-by: H.J. Lu <hjl.tools@gmail.com>
This commit is contained in:
H.J. Lu 2018-09-28 13:31:19 -07:00
parent 7a16bdbb9f
commit 7b1f940676
3 changed files with 21 additions and 69 deletions
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10
ChangeLog
View File

@ -1,3 +1,13 @@
2018-09-28 H.J. Lu <hongjiu.lu@intel.com>
[BZ #23716]
* sysdeps/i386/dl-cet.c: Removed.
* sysdeps/i386/dl-machine.h (_dl_runtime_resolve_shstk): New
prototype.
(_dl_runtime_profile_shstk): Likewise.
(elf_machine_runtime_setup): Use _dl_runtime_profile_shstk or
_dl_runtime_resolve_shstk if SHSTK is enabled by kernel.
2018-09-28 Adhemerval Zanella <adhemerval.zanella@linaro.org>
[BZ #23579]

67
sysdeps/i386/dl-cet.c
View File

@ -1,67 +0,0 @@
/* Linux/i386 CET initializers function.
Copyright (C) 2018 Free Software Foundation, Inc.
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/>. */
#define LINKAGE static inline
#define _dl_cet_check cet_check
#include <sysdeps/x86/dl-cet.c>
#undef _dl_cet_check
#ifdef SHARED
void
_dl_cet_check (struct link_map *main_map, const char *program)
{
cet_check (main_map, program);
if ((GL(dl_x86_feature_1)[0] & GNU_PROPERTY_X86_FEATURE_1_SHSTK))
{
/* Replace _dl_runtime_resolve and _dl_runtime_profile with
_dl_runtime_resolve_shstk and _dl_runtime_profile_shstk,
respectively if SHSTK is enabled. */
extern void _dl_runtime_resolve (Elf32_Word) attribute_hidden;
extern void _dl_runtime_resolve_shstk (Elf32_Word) attribute_hidden;
extern void _dl_runtime_profile (Elf32_Word) attribute_hidden;
extern void _dl_runtime_profile_shstk (Elf32_Word) attribute_hidden;
unsigned int i;
struct link_map *l;
Elf32_Addr *got;
if (main_map->l_info[DT_JMPREL])
{
got = (Elf32_Addr *) D_PTR (main_map, l_info[DT_PLTGOT]);
if (got[2] == (Elf32_Addr) &_dl_runtime_resolve)
got[2] = (Elf32_Addr) &_dl_runtime_resolve_shstk;
else if (got[2] == (Elf32_Addr) &_dl_runtime_profile)
got[2] = (Elf32_Addr) &_dl_runtime_profile_shstk;
}
i = main_map->l_searchlist.r_nlist;
while (i-- > 0)
{
l = main_map->l_initfini[i];
if (l->l_info[DT_JMPREL])
{
got = (Elf32_Addr *) D_PTR (l, l_info[DT_PLTGOT]);
if (got[2] == (Elf32_Addr) &_dl_runtime_resolve)
got[2] = (Elf32_Addr) &_dl_runtime_resolve_shstk;
else if (got[2] == (Elf32_Addr) &_dl_runtime_profile)
got[2] = (Elf32_Addr) &_dl_runtime_profile_shstk;
}
}
}
}
#endif

13
sysdeps/i386/dl-machine.h
View File

@ -67,6 +67,11 @@ elf_machine_runtime_setup (struct link_map *l, int lazy, int profile)
Elf32_Addr *got;
extern void _dl_runtime_resolve (Elf32_Word) attribute_hidden;
extern void _dl_runtime_profile (Elf32_Word) attribute_hidden;
extern void _dl_runtime_resolve_shstk (Elf32_Word) attribute_hidden;
extern void _dl_runtime_profile_shstk (Elf32_Word) attribute_hidden;
/* Check if SHSTK is enabled by kernel. */
bool shstk_enabled
= (GL(dl_x86_feature_1)[0] & GNU_PROPERTY_X86_FEATURE_1_SHSTK) != 0;
if (l->l_info[DT_JMPREL] && lazy)
{
@ -93,7 +98,9 @@ elf_machine_runtime_setup (struct link_map *l, int lazy, int profile)
end in this function. */
if (__glibc_unlikely (profile))
{
got[2] = (Elf32_Addr) &_dl_runtime_profile;
got[2] = (shstk_enabled
? (Elf32_Addr) &_dl_runtime_profile_shstk
: (Elf32_Addr) &_dl_runtime_profile);
if (GLRO(dl_profile) != NULL
&& _dl_name_match_p (GLRO(dl_profile), l))
@ -104,7 +111,9 @@ elf_machine_runtime_setup (struct link_map *l, int lazy, int profile)
else
/* This function will get called to fix up the GOT entry indicated by
the offset on the stack, and then jump to the resolved address. */
got[2] = (Elf32_Addr) &_dl_runtime_resolve;
got[2] = (shstk_enabled
? (Elf32_Addr) &_dl_runtime_resolve_shstk
: (Elf32_Addr) &_dl_runtime_resolve);
}
return lazy;