sysdeps/unix/sysv/linux/x86_64/pointer_guard.h

   1 /* Pointer obfuscation implenentation.  x86-64 version.
   2    Copyright (C) 2005-2024 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <https://www.gnu.org/licenses/>.  */
  18
  19 #ifndef POINTER_GUARD_H
  20 #define POINTER_GUARD_H
  21
  22 #include <x86-lp_size.h>
  23 #include <tcb-offsets.h>
  24
  25 #if IS_IN (rtld)
  26 /* We cannot use the thread descriptor because in ld.so we use setjmp
  27    earlier than the descriptor is initialized.  */
  28 # ifdef __ASSEMBLER__
  29 #  define PTR_MANGLE(reg)       xor __pointer_chk_guard_local(%rip), reg;    \
  30                                 rol $2*LP_SIZE+1, reg
  31 #  define PTR_DEMANGLE(reg)     ror $2*LP_SIZE+1, reg;                       \
  32                                 xor __pointer_chk_guard_local(%rip), reg
  33 # else
  34 #  define PTR_MANGLE(reg)       asm ("xor __pointer_chk_guard_local(%%rip), %0\n" \
  35                                      "rol $2*" LP_SIZE "+1, %0"                   \
  36                                      : "=r" (reg) : "0" (reg))
  37 #  define PTR_DEMANGLE(reg)     asm ("ror $2*" LP_SIZE "+1, %0\n"                 \
  38                                      "xor __pointer_chk_guard_local(%%rip), %0"   \
  39                                      : "=r" (reg) : "0" (reg))
  40 # endif
  41 #else
  42 # ifdef __ASSEMBLER__
  43 #  define PTR_MANGLE(reg)       xor %fs:POINTER_GUARD, reg;                   \
  44                                 rol $2*LP_SIZE+1, reg
  45 #  define PTR_DEMANGLE(reg)     ror $2*LP_SIZE+1, reg;                        \
  46                                 xor %fs:POINTER_GUARD, reg
  47 # else
  48 #  define PTR_MANGLE(var)       asm ("xor %%fs:%c2, %0\n"                     \
  49                                      "rol $2*" LP_SIZE "+1, %0"               \
  50                                      : "=r" (var)                             \
  51                                      : "0" (var),                             \
  52                                        "i" (POINTER_GUARD))
  53 #  define PTR_DEMANGLE(var)     asm ("ror $2*" LP_SIZE "+1, %0\n"             \
  54                                      "xor %%fs:%c2, %0"                       \
  55                                      : "=r" (var)                             \
  56                                      : "0" (var),                             \
  57                                        "i" (POINTER_GUARD))
  58 # endif
  59 #endif
  60
  61 #endif /* POINTER_GUARD_H */