include/ssp/ssp.h

   1 /*      $NetBSD: ssp.h,v 1.13 2015/09/03 20:43:47 plunky Exp $  */
   2
   3 /*-
   4  *
   5  * SPDX-License-Identifier: BSD-2-Clause
   6  *
   7  * Copyright (c) 2006, 2011 The NetBSD Foundation, Inc.
   8  * All rights reserved.
   9  *
  10  * This code is derived from software contributed to The NetBSD Foundation
  11  * by Christos Zoulas.
  12  *
  13  * Redistribution and use in source and binary forms, with or without
  14  * modification, are permitted provided that the following conditions
  15  * are met:
  16  * 1. Redistributions of source code must retain the above copyright
  17  *    notice, this list of conditions and the following disclaimer.
  18  * 2. Redistributions in binary form must reproduce the above copyright
  19  *    notice, this list of conditions and the following disclaimer in the
  20  *    documentation and/or other materials provided with the distribution.
  21  *
  22  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
  23  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
  24  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  25  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
  26  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  27  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  28  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  29  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  30  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  31  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  32  * POSSIBILITY OF SUCH DAMAGE.
  33  */
  34 #ifndef _SSP_SSP_H_
  35 #define _SSP_SSP_H_
  36
  37 #include <sys/cdefs.h>
  38
  39 #if !defined(__cplusplus)
  40 # if defined(_FORTIFY_SOURCE) && _FORTIFY_SOURCE > 0 && \
  41      (__OPTIMIZE__ > 0 || defined(__clang__))
  42 #  if _FORTIFY_SOURCE > 1
  43 #   define __SSP_FORTIFY_LEVEL 2
  44 #  else
  45 #   define __SSP_FORTIFY_LEVEL 1
  46 #  endif
  47 # else
  48 #  define __SSP_FORTIFY_LEVEL 0
  49 # endif
  50 #else
  51 # define __SSP_FORTIFY_LEVEL 0
  52 #endif
  53
  54 #define __ssp_var(type) __CONCAT(__ssp_ ## type, __COUNTER__)
  55
  56 /* __ssp_real is used by the implementation in libc */
  57 #if __SSP_FORTIFY_LEVEL == 0
  58 #define __ssp_real_(fun)        fun
  59 #else
  60 #define __ssp_real_(fun)        __ssp_real_ ## fun
  61 #endif
  62 #define __ssp_real(fun)         __ssp_real_(fun)
  63
  64 #define __ssp_inline static __inline __attribute__((__always_inline__))
  65
  66 #define __ssp_bos(ptr) __builtin_object_size(ptr, __SSP_FORTIFY_LEVEL > 1)
  67 #define __ssp_bos0(ptr) __builtin_object_size(ptr, 0)
  68
  69 #define __ssp_check(buf, len, bos) \
  70         if (bos(buf) != (size_t)-1 && (size_t)len > bos(buf)) \
  71                 __chk_fail()
  72
  73 #define __ssp_redirect_raw_impl(rtype, fun, symbol, args) \
  74 rtype __ssp_real_(fun) args __RENAME(symbol); \
  75 __ssp_inline rtype fun args __RENAME(__ssp_protected_ ## fun); \
  76 __ssp_inline rtype fun args
  77
  78 #define __ssp_redirect_raw(rtype, fun, symbol, args, call, cond, bos, len) \
  79 __ssp_redirect_raw_impl(rtype, fun, symbol, args) { \
  80         if (cond) \
  81                 __ssp_check(__buf, len, bos); \
  82         return __ssp_real_(fun) call; \
  83 }
  84
  85 #define __ssp_redirect(rtype, fun, args, call) \
  86     __ssp_redirect_raw(rtype, fun, fun, args, call, 1, __ssp_bos, __len)
  87 #define __ssp_redirect0(rtype, fun, args, call) \
  88     __ssp_redirect_raw(rtype, fun, fun, args, call, 1, __ssp_bos0, __len)
  89
  90 #include <machine/_limits.h>
  91
  92 __ssp_inline int
  93 __ssp_overlap(const void *leftp, const void *rightp, __size_t sz)
  94 {
  95         __uintptr_t left = (__uintptr_t)leftp;
  96         __uintptr_t right = (__uintptr_t)rightp;
  97
  98         if (left <= right)
  99                 return (__SIZE_T_MAX - sz < left || right < left + sz);
 100
 101         return (__SIZE_T_MAX - sz < right || left < right + sz);
 102 }
 103
 104 #include <sys/_iovec.h>
 105
 106 __BEGIN_DECLS
 107 void __stack_chk_fail(void) __dead2;
 108 void __chk_fail(void) __dead2;
 109 __END_DECLS
 110
 111 __ssp_inline void
 112 __ssp_check_iovec(const struct iovec *iov, int iovcnt)
 113 {
 114         const size_t iovsz = __ssp_bos(iov);
 115         int i;
 116
 117         if (iovsz != (size_t)-1 && iovsz / sizeof(*iov) < (size_t)iovcnt)
 118                 __chk_fail();
 119
 120         for (i = 0; i < iovcnt; i++) {
 121                 if (__ssp_bos(iov[i].iov_base) < iov[i].iov_len)
 122                         __chk_fail();
 123         }
 124 }
 125
 126 #endif /* _SSP_SSP_H_ */