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