1 | /* Bounded-pointer checking macros for C. |
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2 | Copyright (C) 2000 Free Software Foundation, Inc. |
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3 | This file is part of the GNU C Library. |
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4 | Contributed by Greg McGary <greg@mcgary.org> |
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5 | |
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6 | The GNU C Library is free software; you can redistribute it and/or |
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7 | modify it under the terms of the GNU Lesser General Public |
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8 | License as published by the Free Software Foundation; either |
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9 | version 2.1 of the License, or (at your option) any later version. |
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10 | |
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11 | The GNU C Library is distributed in the hope that it will be useful, |
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12 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
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13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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14 | Lesser General Public License for more details. |
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15 | |
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16 | You should have received a copy of the GNU Lesser General Public |
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17 | License along with the GNU C Library; if not, write to the Free |
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18 | Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA |
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19 | 02111-1307 USA. */ |
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20 | |
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21 | #ifndef _bp_checks_h_ |
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22 | #define _bp_checks_h_ 1 |
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23 | |
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24 | #if __BOUNDED_POINTERS__ |
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25 | |
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26 | # define BOUNDS_VIOLATED (__builtin_trap (), 0) |
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27 | |
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28 | /* Verify that pointer's value >= low. Return pointer value. */ |
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29 | # define CHECK_BOUNDS_LOW(ARG) \ |
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30 | (((__ptrvalue (ARG) < __ptrlow (ARG)) && BOUNDS_VIOLATED), \ |
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31 | __ptrvalue (ARG)) |
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32 | |
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33 | /* Verify that pointer's value < high. Return pointer value. */ |
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34 | # define CHECK_BOUNDS_HIGH(ARG) \ |
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35 | (((__ptrvalue (ARG) > __ptrhigh (ARG)) && BOUNDS_VIOLATED), \ |
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36 | __ptrvalue (ARG)) |
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37 | |
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38 | # define _CHECK_N(ARG, N, COND) \ |
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39 | (((COND) \ |
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40 | && (__ptrvalue (ARG) < __ptrlow (ARG) \ |
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41 | || __ptrvalue (ARG) + (N) > __ptrhigh (ARG)) \ |
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42 | && BOUNDS_VIOLATED), \ |
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43 | __ptrvalue (ARG)) |
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44 | |
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45 | extern void *__unbounded __ubp_memchr (const void *__unbounded, int, unsigned); |
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46 | |
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47 | # define _CHECK_STRING(ARG, COND) \ |
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48 | (((COND) \ |
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49 | && (__ptrvalue (ARG) < __ptrlow (ARG) \ |
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50 | || !__ubp_memchr (__ptrvalue (ARG), '\0', \ |
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51 | (__ptrhigh (ARG) - __ptrvalue (ARG)))) \ |
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52 | && BOUNDS_VIOLATED), \ |
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53 | __ptrvalue (ARG)) |
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54 | |
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55 | /* Check bounds of a pointer seated to an array of N objects. */ |
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56 | # define CHECK_N(ARG, N) _CHECK_N ((ARG), (N), 1) |
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57 | /* Same as CHECK_N, but tolerate ARG == NULL. */ |
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58 | # define CHECK_N_NULL_OK(ARG, N) _CHECK_N ((ARG), (N), __ptrvalue (ARG)) |
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59 | |
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60 | /* Check bounds of a pointer seated to a single object. */ |
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61 | # define CHECK_1(ARG) CHECK_N ((ARG), 1) |
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62 | /* Same as CHECK_1, but tolerate ARG == NULL. */ |
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63 | # define CHECK_1_NULL_OK(ARG) CHECK_N_NULL_OK ((ARG), 1) |
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64 | |
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65 | /* Check for NUL-terminator within string's bounds. */ |
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66 | # define CHECK_STRING(ARG) _CHECK_STRING ((ARG), 1) |
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67 | /* Same as CHECK_STRING, but tolerate ARG == NULL. */ |
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68 | # define CHECK_STRING_NULL_OK(ARG) _CHECK_STRING ((ARG), __ptrvalue (ARG)) |
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69 | |
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70 | /* Check bounds of signal syscall args with type sigset_t. */ |
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71 | # define CHECK_SIGSET(SET) CHECK_N ((SET), _NSIG / (8 * sizeof *(SET))) |
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72 | /* Same as CHECK_SIGSET, but tolerate SET == NULL. */ |
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73 | # define CHECK_SIGSET_NULL_OK(SET) CHECK_N_NULL_OK ((SET), _NSIG / (8 * sizeof *(SET))) |
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74 | |
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75 | # if defined (_IOC_SIZESHIFT) && defined (_IOC_SIZEBITS) |
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76 | /* Extract the size of the ioctl data and check its bounds. */ |
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77 | # define CHECK_IOCTL(ARG, CMD) \ |
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78 | CHECK_N ((const char *) (ARG), \ |
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79 | (((CMD) >> _IOC_SIZESHIFT) & ((1 << _IOC_SIZEBITS) - 1))) |
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80 | # else |
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81 | /* We don't know the size of the ioctl data, so the best we can do |
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82 | is check that the first byte is within bounds. */ |
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83 | # define CHECK_IOCTL(ARG, CMD) CHECK_1 ((const char *) ARG) |
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84 | # endif |
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85 | |
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86 | /* Check bounds of `struct flock *' for the locking fcntl commands. */ |
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87 | # define CHECK_FCNTL(ARG, CMD) \ |
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88 | (((CMD) == F_GETLK || (CMD) == F_SETLK || (CMD) == F_SETLKW) \ |
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89 | ? CHECK_1 ((struct flock *) ARG) : (unsigned long) (ARG)) |
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90 | |
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91 | /* Check bounds of an array of mincore residency-status flags that |
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92 | cover a region of NBYTES. Such a vector occupies one byte per page |
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93 | of memory. */ |
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94 | # define CHECK_N_PAGES(ARG, NBYTES) \ |
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95 | ({ int _page_size_ = sysconf (_SC_PAGE_SIZE); \ |
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96 | CHECK_N ((const char *) (ARG), \ |
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97 | ((NBYTES) + _page_size_ - 1) / _page_size_); }) |
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98 | |
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99 | /* Return a bounded pointer with value PTR that satisfies CHECK_N (PTR, N). */ |
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100 | # define BOUNDED_N(PTR, N) \ |
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101 | ({ __typeof (PTR) __bounded _p_; \ |
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102 | __ptrvalue _p_ = __ptrlow _p_ = __ptrvalue (PTR); \ |
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103 | __ptrhigh _p_ = __ptrvalue _p_ + (N); \ |
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104 | _p_; }) |
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105 | |
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106 | #else /* !__BOUNDED_POINTERS__ */ |
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107 | |
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108 | /* Do nothing if not compiling with -fbounded-pointers. */ |
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109 | |
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110 | # define BOUNDS_VIOLATED |
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111 | # define CHECK_BOUNDS_LOW(ARG) (ARG) |
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112 | # define CHECK_BOUNDS_HIGH(ARG) (ARG) |
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113 | # define CHECK_1(ARG) (ARG) |
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114 | # define CHECK_1_NULL_OK(ARG) (ARG) |
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115 | # define CHECK_N(ARG, N) (ARG) |
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116 | # define CHECK_N_NULL_OK(ARG, N) (ARG) |
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117 | # define CHECK_STRING(ARG) (ARG) |
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118 | # define CHECK_SIGSET(SET) (SET) |
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119 | # define CHECK_SIGSET_NULL_OK(SET) (SET) |
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120 | # define CHECK_IOCTL(ARG, CMD) (ARG) |
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121 | # define CHECK_FCNTL(ARG, CMD) (ARG) |
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122 | # define CHECK_N_PAGES(ARG, NBYTES) (ARG) |
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123 | # define BOUNDED_N(PTR, N) (PTR) |
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124 | |
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125 | #endif /* !__BOUNDED_POINTERS__ */ |
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126 | |
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127 | #define BOUNDED_1(PTR) BOUNDED_N (PTR, 1) |
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128 | |
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129 | #endif /* _bp_checks_h_ */ |
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