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glibc/sysdeps/unix/sysv/linux/csky/pointer_guard.h

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Introduce <pointer_guard.h>, extracted from <sysdep.h> This allows us to define a generic no-op version of PTR_MANGLE and PTR_DEMANGLE. In the future, we can use PTR_MANGLE and PTR_DEMANGLE unconditionally in C sources, avoiding an unintended loss of hardening due to missing include files or unlucky header inclusion ordering. In i386 and x86_64, we can avoid a <tls.h> dependency in the C code by using the computed constant from <tcb-offsets.h>. <sysdep.h> no longer includes these definitions, so there is no cyclic dependency anymore when computing the <tcb-offsets.h> constants. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
2022-10-18 15:00:07 +00:00
/* Pointer obfuscation implenentation. C-SKY version.
Update copyright dates with scripts/update-copyrights
2023-01-06 21:08:04 +00:00
Copyright (C) 2022-2023 Free Software Foundation, Inc.
Introduce <pointer_guard.h>, extracted from <sysdep.h> This allows us to define a generic no-op version of PTR_MANGLE and PTR_DEMANGLE. In the future, we can use PTR_MANGLE and PTR_DEMANGLE unconditionally in C sources, avoiding an unintended loss of hardening due to missing include files or unlucky header inclusion ordering. In i386 and x86_64, we can avoid a <tls.h> dependency in the C code by using the computed constant from <tcb-offsets.h>. <sysdep.h> no longer includes these definitions, so there is no cyclic dependency anymore when computing the <tcb-offsets.h> constants. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
2022-10-18 15:00:07 +00:00
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/>. */
#ifndef POINTER_GUARD_H
#define POINTER_GUARD_H
#if (IS_IN (rtld) \
|| (!defined SHARED && (IS_IN (libc) || IS_IN (libpthread))))
# ifdef __ASSEMBLER__
# define PTR_MANGLE(dst, src, guard) \
grs t0, 1f; \
1: \
lrw guard, 1b@GOTPC; \
addu t0, guard; \
lrw guard, __pointer_chk_guard_local@GOT; \
ldr.w guard, (t0, guard << 0); \
ldw guard, (guard, 0); \
xor dst, src, guard;
# define PTR_DEMANGLE(dst, src, guard) PTR_MANGLE (dst, src, guard)
# define PTR_MANGLE2(dst, src, guard) \
xor dst, src, guard
# define PTR_DEMANGLE2(dst, src, guard) PTR_MANGLE2 (dst, src, guard)
# else
extern uintptr_t __pointer_chk_guard_local;
# define PTR_MANGLE(var) \
(var) = (__typeof (var)) ((uintptr_t) (var) ^ __pointer_chk_guard_local)
# define PTR_DEMANGLE(var) PTR_MANGLE (var)
# endif
#else
# ifdef __ASSEMBLER__
# define PTR_MANGLE(dst, src, guard) \
grs t0, 1f; \
1: \
lrw guard, 1b@GOTPC; \
addu t0, guard; \
lrw guard, __pointer_chk_guard@GOT; \
ldr.w guard, (t0, guard << 0); \
ldw guard, (guard, 0); \
xor dst, src, guard;
# define PTR_DEMANGLE(dst, src, guard) PTR_MANGLE (dst, src, guard)
# define PTR_MANGLE2(dst, src, guard) \
xor dst, src, guard
# define PTR_DEMANGLE2(dst, src, guard) PTR_MANGLE2 (dst, src, guard)
# else
# include <stdint.h>
extern uintptr_t __pointer_chk_guard;
# define PTR_MANGLE(var) \
(var) = (__typeof (var)) ((uintptr_t) (var) ^ __pointer_chk_guard)
# define PTR_DEMANGLE(var) PTR_MANGLE (var)
# endif
#endif
#endif /* POINTER_GUARD_H */
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