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      1 /*	$NetBSD: ssp.h,v 1.16 2023/11/15 03:14:16 christos Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 2006, 2011, 2023 The NetBSD Foundation, Inc.
      5  * All rights reserved.
      6  *
      7  * This code is derived from software contributed to The NetBSD Foundation
      8  * by Christos Zoulas.
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted provided that the following conditions
     12  * are met:
     13  * 1. Redistributions of source code must retain the above copyright
     14  *    notice, this list of conditions and the following disclaimer.
     15  * 2. Redistributions in binary form must reproduce the above copyright
     16  *    notice, this list of conditions and the following disclaimer in the
     17  *    documentation and/or other materials provided with the distribution.
     18  *
     19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     29  * POSSIBILITY OF SUCH DAMAGE.
     30  */
     31 #ifndef _SSP_SSP_H_
     32 #define _SSP_SSP_H_
     33 
     34 #include <sys/cdefs.h>
     35 
     36 #if !defined(__cplusplus)
     37 # if _FORTIFY_SOURCE > 0 && !defined(__lint__) && \
     38      (__OPTIMIZE__ > 0 || defined(__clang__)) && __GNUC_PREREQ__(4, 1)
     39 #  if _FORTIFY_SOURCE > 2 && __has_builtin(__builtin_dynamic_object_size)
     40 #   define __SSP_FORTIFY_LEVEL 3
     41 #  elif _FORTIFY_SOURCE > 1
     42 #   define __SSP_FORTIFY_LEVEL 2
     43 #  else
     44 #   define __SSP_FORTIFY_LEVEL 1
     45 #  endif
     46 # else
     47 #  define __SSP_FORTIFY_LEVEL 0
     48 # endif
     49 #else
     50 # define __SSP_FORTIFY_LEVEL 0
     51 #endif
     52 
     53 /* __ssp_real is used by the implementation in libc */
     54 #if __SSP_FORTIFY_LEVEL == 0
     55 #define __ssp_real_(fun)	fun
     56 #else
     57 #define __ssp_real_(fun)	__ssp_real_ ## fun
     58 #endif
     59 #define __ssp_real(fun)		__ssp_real_(fun)
     60 
     61 #ifndef __ssp_inline
     62 #define __ssp_inline extern __inline \
     63     __attribute__((__always_inline__, __gnu_inline__))
     64 #endif
     65 
     66 #if __SSP_FORTIFY_LEVEL > 2
     67 # define __ssp_bos(ptr) __builtin_dynamic_object_size(ptr, 1)
     68 # define __ssp_bos0(ptr) __builtin_dynamic_object_size(ptr, 0)
     69 #else
     70 # define __ssp_bos(ptr) __builtin_object_size(ptr, __SSP_FORTIFY_LEVEL > 1)
     71 # define __ssp_bos0(ptr) __builtin_object_size(ptr, 0)
     72 #endif
     73 
     74 #define __ssp_check(buf, len, bos) \
     75 	if (bos(buf) != (size_t)-1 && len > bos(buf)) \
     76 		__chk_fail()
     77 #define __ssp_redirect_raw(rtype, fun, symbol, args, call, cond, bos) \
     78 rtype __ssp_real_(fun) args __RENAME(symbol); \
     79 __ssp_inline rtype fun args __RENAME(__ssp_protected_ ## fun); \
     80 __ssp_inline rtype fun args { \
     81 	if (cond) \
     82 		__ssp_check(__buf, __len, bos); \
     83 	return __ssp_real_(fun) call; \
     84 }
     85 
     86 #define __ssp_redirect(rtype, fun, args, call) \
     87     __ssp_redirect_raw(rtype, fun, fun, args, call, 1, __ssp_bos)
     88 #define __ssp_redirect0(rtype, fun, args, call) \
     89     __ssp_redirect_raw(rtype, fun, fun, args, call, 1, __ssp_bos0)
     90 
     91 #define __ssp_overlap(a, b, l) \
     92     (((a) <= (b) && (b) < (a) + (l)) || ((b) <= (a) && (a) < (b) + (l)))
     93 
     94 __BEGIN_DECLS
     95 void __stack_chk_fail(void) __dead;
     96 void __chk_fail(void) __dead;
     97 __END_DECLS
     98 
     99 #endif /* _SSP_SSP_H_ */
    100