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| author | Florian Weimer <fweimer@redhat.com> | 2022-10-18 17:00:07 +0200 |
|---|---|---|
| committer | Florian Weimer <fweimer@redhat.com> | 2022-10-18 17:03:55 +0200 |
| commit | 88f4b6929c26f9240a4b0b7dcc62922f02544a09 (patch) | |
| tree | 72acb4a359d3ec56729a910386bd1a002bd69e3c /sysdeps/arm/sysdep.h | |
| parent | 246f37d6b1c4c6c0a6365df8783e62e3adf208e8 (diff) | |
| download | glibc-88f4b6929c26f9240a4b0b7dcc62922f02544a09.zip glibc-88f4b6929c26f9240a4b0b7dcc62922f02544a09.tar.gz glibc-88f4b6929c26f9240a4b0b7dcc62922f02544a09.tar.bz2 | |
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>
Diffstat (limited to 'sysdeps/arm/sysdep.h')
| -rw-r--r-- | sysdeps/arm/sysdep.h | 44 |
1 files changed, 0 insertions, 44 deletions
diff --git a/sysdeps/arm/sysdep.h b/sysdeps/arm/sysdep.h index f19146b..ffd848d 100644 --- a/sysdeps/arm/sysdep.h +++ b/sysdeps/arm/sysdep.h @@ -293,47 +293,3 @@ #else # define PC_OFS 8 #endif - -/* Pointer mangling support. */ -#if (IS_IN (rtld) \ - || (!defined SHARED && (IS_IN (libc) || IS_IN (libpthread)))) -# ifdef __ASSEMBLER__ -# define PTR_MANGLE_LOAD(guard, tmp) \ - LDR_HIDDEN (guard, tmp, C_SYMBOL_NAME(__pointer_chk_guard_local), 0) -# define PTR_MANGLE(dst, src, guard, tmp) \ - PTR_MANGLE_LOAD(guard, tmp); \ - PTR_MANGLE2(dst, src, guard) -/* Use PTR_MANGLE2 for efficiency if guard is already loaded. */ -# define PTR_MANGLE2(dst, src, guard) \ - eor dst, src, guard -# define PTR_DEMANGLE(dst, src, guard, tmp) \ - PTR_MANGLE (dst, src, guard, tmp) -# define PTR_DEMANGLE2(dst, src, guard) \ - PTR_MANGLE2 (dst, src, guard) -# else -extern uintptr_t __pointer_chk_guard_local attribute_relro attribute_hidden; -# 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_LOAD(guard, tmp) \ - LDR_GLOBAL (guard, tmp, C_SYMBOL_NAME(__pointer_chk_guard), 0); -# define PTR_MANGLE(dst, src, guard, tmp) \ - PTR_MANGLE_LOAD(guard, tmp); \ - PTR_MANGLE2(dst, src, guard) -/* Use PTR_MANGLE2 for efficiency if guard is already loaded. */ -# define PTR_MANGLE2(dst, src, guard) \ - eor dst, src, guard -# define PTR_DEMANGLE(dst, src, guard, tmp) \ - PTR_MANGLE (dst, src, guard, tmp) -# define PTR_DEMANGLE2(dst, src, guard) \ - PTR_MANGLE2 (dst, src, guard) -# else -extern uintptr_t __pointer_chk_guard attribute_relro; -# define PTR_MANGLE(var) \ - (var) = (__typeof (var)) ((uintptr_t) (var) ^ __pointer_chk_guard) -# define PTR_DEMANGLE(var) PTR_MANGLE (var) -# endif -#endif |