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author | Florian Weimer <fweimer@redhat.com> | 2022-10-18 17:00:07 +0200 |
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committer | Florian Weimer <fweimer@redhat.com> | 2022-10-18 17:03:55 +0200 |
commit | 88f4b6929c26f9240a4b0b7dcc62922f02544a09 (patch) | |
tree | 72acb4a359d3ec56729a910386bd1a002bd69e3c /sysdeps/unix/sysv/linux/x86_64/sysdep.h | |
parent | 246f37d6b1c4c6c0a6365df8783e62e3adf208e8 (diff) | |
download | glibc-88f4b6929c26f9240a4b0b7dcc62922f02544a09.tar.gz glibc-88f4b6929c26f9240a4b0b7dcc62922f02544a09.tar.xz glibc-88f4b6929c26f9240a4b0b7dcc62922f02544a09.zip |
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/unix/sysv/linux/x86_64/sysdep.h')
-rw-r--r-- | sysdeps/unix/sysv/linux/x86_64/sysdep.h | 40 |
1 files changed, 0 insertions, 40 deletions
diff --git a/sysdeps/unix/sysv/linux/x86_64/sysdep.h b/sysdeps/unix/sysv/linux/x86_64/sysdep.h index 740abefcfd..5e4d7827d7 100644 --- a/sysdeps/unix/sysv/linux/x86_64/sysdep.h +++ b/sysdeps/unix/sysv/linux/x86_64/sysdep.h @@ -381,46 +381,6 @@ #endif /* __ASSEMBLER__ */ - -/* Pointer mangling support. */ -#if IS_IN (rtld) -/* We cannot use the thread descriptor because in ld.so we use setjmp - earlier than the descriptor is initialized. */ -# ifdef __ASSEMBLER__ -# define PTR_MANGLE(reg) xor __pointer_chk_guard_local(%rip), reg; \ - rol $2*LP_SIZE+1, reg -# define PTR_DEMANGLE(reg) ror $2*LP_SIZE+1, reg; \ - xor __pointer_chk_guard_local(%rip), reg -# else -# define PTR_MANGLE(reg) asm ("xor __pointer_chk_guard_local(%%rip), %0\n" \ - "rol $2*" LP_SIZE "+1, %0" \ - : "=r" (reg) : "0" (reg)) -# define PTR_DEMANGLE(reg) asm ("ror $2*" LP_SIZE "+1, %0\n" \ - "xor __pointer_chk_guard_local(%%rip), %0" \ - : "=r" (reg) : "0" (reg)) -# endif -#else -# ifdef __ASSEMBLER__ -# define PTR_MANGLE(reg) xor %fs:POINTER_GUARD, reg; \ - rol $2*LP_SIZE+1, reg -# define PTR_DEMANGLE(reg) ror $2*LP_SIZE+1, reg; \ - xor %fs:POINTER_GUARD, reg -# else -# define PTR_MANGLE(var) asm ("xor %%fs:%c2, %0\n" \ - "rol $2*" LP_SIZE "+1, %0" \ - : "=r" (var) \ - : "0" (var), \ - "i" (offsetof (tcbhead_t, \ - pointer_guard))) -# define PTR_DEMANGLE(var) asm ("ror $2*" LP_SIZE "+1, %0\n" \ - "xor %%fs:%c2, %0" \ - : "=r" (var) \ - : "0" (var), \ - "i" (offsetof (tcbhead_t, \ - pointer_guard))) -# endif -#endif - /* How to pass the off{64}_t argument on p{readv,writev}{64}. */ #undef LO_HI_LONG #define LO_HI_LONG(val) (val), 0 |