sysdeps/generic/bp-checks.h

   1 /* Bounded-pointer checking macros for C.
   2    Copyright (C) 2000 Free Software Foundation, Inc.
   3    Contributed by Greg McGary <greg@mcgary.org>
   4
   5    This file is part of the GNU C Library.  Its master source is NOT part of
   6    the C library, however.  The master source lives in the GNU MP Library.
   7
   8    The GNU C Library is free software; you can redistribute it and/or
   9    modify it under the terms of the GNU Library General Public License as
  10    published by the Free Software Foundation; either version 2 of the
  11    License, or (at your option) any later version.
  12
  13    The GNU C Library is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16    Library General Public License for more details.
  17
  18    You should have received a copy of the GNU Library General Public
  19    License along with the GNU C Library; see the file COPYING.LIB.  If not,
  20    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  21    Boston, MA 02111-1307, USA.  */
  22
  23 #ifndef _bp_checks_h_
  24 #define _bp_checks_h_ 1
  25
  26 #if __BOUNDED_POINTERS__
  27
  28 # define BOUNDS_VIOLATED (__builtin_trap (), 0)
  29
  30 /* Verify that pointer's value >= low.  Return pointer value.  */
  31 # define CHECK_BOUNDS_LOW(ARG)                                  \
  32   (((__ptrvalue (ARG) < __ptrlow (ARG)) && BOUNDS_VIOLATED),    \
  33    __ptrvalue (ARG))
  34
  35 /* Verify that pointer's value < high.  Return pointer value.  */
  36 # define CHECK_BOUNDS_HIGH(ARG)                         \
  37   (((__ptrvalue (ARG) > __ptrhigh (ARG)) && BOUNDS_VIOLATED),   \
  38    __ptrvalue (ARG))
  39
  40 # define _CHECK_N(ARG, N, COND)                         \
  41   (((COND)                                              \
  42     && (__ptrvalue (ARG) < __ptrlow (ARG)               \
  43         || __ptrvalue (ARG) + (N) > __ptrhigh (ARG))    \
  44     && BOUNDS_VIOLATED),                                \
  45    __ptrvalue (ARG))
  46
  47 extern void *__unbounded __ubp_memchr (const void *__unbounded, int, unsigned);
  48
  49 # define _CHECK_STRING(ARG, COND)                               \
  50   (((COND)                                                      \
  51     && (__ptrvalue (ARG) < __ptrlow (ARG)                       \
  52         || !__ubp_memchr (__ptrvalue (ARG), '\0',                       \
  53                       (__ptrhigh (ARG) - __ptrvalue (ARG))))    \
  54     && BOUNDS_VIOLATED),                                        \
  55    __ptrvalue (ARG))
  56
  57 /* Check bounds of a pointer seated to an array of N objects.  */
  58 # define CHECK_N(ARG, N) _CHECK_N ((ARG), (N), 1)
  59 /* Same as CHECK_N, but tolerate ARG == NULL.  */
  60 # define CHECK_N_NULL_OK(ARG, N) _CHECK_N ((ARG), (N), __ptrvalue (ARG))
  61
  62 /* Check bounds of a pointer seated to a single object.  */
  63 # define CHECK_1(ARG) CHECK_N ((ARG), 1)
  64 /* Same as CHECK_1, but tolerate ARG == NULL.  */
  65 # define CHECK_1_NULL_OK(ARG) CHECK_N_NULL_OK ((ARG), 1)
  66
  67 /* Check for NUL-terminator within string's bounds.  */
  68 # define CHECK_STRING(ARG) _CHECK_STRING ((ARG), 1)
  69 /* Same as CHECK_STRING, but tolerate ARG == NULL.  */
  70 # define CHECK_STRING_NULL_OK(ARG) _CHECK_STRING ((ARG), __ptrvalue (ARG))
  71
  72 /* Check bounds of signal syscall args with type sigset_t.  */
  73 # define CHECK_SIGSET(SET) CHECK_N ((SET), _NSIG / (8 * sizeof *(SET)))
  74 /* Same as CHECK_SIGSET, but tolerate SET == NULL.  */
  75 # define CHECK_SIGSET_NULL_OK(SET) CHECK_N_NULL_OK ((SET), _NSIG / (8 * sizeof *(SET)))
  76
  77 # if defined (_IOC_SIZESHIFT) && defined (_IOC_SIZEBITS)
  78 /* Extract the size of the ioctl data and check its bounds.  */
  79 #  define CHECK_IOCTL(ARG, CMD)                                         \
  80   CHECK_N ((const char *) (ARG),                                        \
  81            (((CMD) >> _IOC_SIZESHIFT) & ((1 << _IOC_SIZEBITS) - 1)))
  82 # else
  83 /* We don't know the size of the ioctl data, so the best we can do
  84    is check that the first byte is within bounds.  */
  85 #  define CHECK_IOCTL(ARG, CMD) CHECK_1 ((const char *) ARG)
  86 # endif
  87
  88 /* Check bounds of `struct flock *' for the locking fcntl commands.  */
  89 # define CHECK_FCNTL(ARG, CMD)                                  \
  90   (((CMD) == F_GETLK || (CMD) == F_SETLK || (CMD) == F_SETLKW)  \
  91    ? CHECK_1 ((struct flock *) ARG) : (unsigned long) (ARG))
  92
  93 /* Return a bounded pointer with value PTR that satisfies CHECK_N (PTR, N).  */
  94 # define BOUNDED_N(PTR, N)                              \
  95   ({ __typeof (PTR) __bounded _p_;                      \
  96      __ptrvalue _p_ = __ptrlow _p_ = __ptrvalue (PTR);  \
  97      __ptrhigh _p_ = __ptrvalue _p_ + (N);              \
  98      _p_; })
  99
 100 #else /* !__BOUNDED_POINTERS__ */
 101
 102 /* Do nothing if not compiling with -fbounded-pointers.  */
 103
 104 # define BOUNDS_VIOLATED
 105 # define CHECK_BOUNDS_LOW(ARG) (ARG)
 106 # define CHECK_BOUNDS_HIGH(ARG) (ARG)
 107 # define CHECK_1(ARG) (ARG)
 108 # define CHECK_1_NULL_OK(ARG) (ARG)
 109 # define CHECK_N(ARG, N) (ARG)
 110 # define CHECK_N_NULL_OK(ARG, N) (ARG)
 111 # define CHECK_STRING(ARG) (ARG)
 112 # define CHECK_SIGSET(SET) (SET)
 113 # define CHECK_SIGSET_NULL_OK(SET) (SET)
 114 # define CHECK_IOCTL(ARG, CMD) (ARG)
 115 # define CHECK_FCNTL(ARG, CMD) (ARG)
 116 # define BOUNDED_N(PTR, N) (PTR)
 117
 118 #endif /* !__BOUNDED_POINTERS__ */
 119
 120 #define BOUNDED_1(PTR) BOUNDED_N (PTR, 1)
 121
 122 #endif /* _bp_checks_h_ */