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/*
* Copyright (C) 2014 The Android Open Source Project
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#undef _FORTIFY_SOURCE
#include <string.h>
#include <stdlib.h>
#include "private/libc_logging.h"
/*
* Runtime implementation of __builtin____stpncpy_chk.
*
* See
* http://gcc.gnu.org/onlinedocs/gcc/Object-Size-Checking.html
* http://gcc.gnu.org/ml/gcc-patches/2004-09/msg02055.html
* for details.
*
* This stpncpy check is called if _FORTIFY_SOURCE is defined and
* greater than 0.
*/
extern "C" char* __stpncpy_chk(char* __restrict dest, const char* __restrict src,
size_t len, size_t dest_len) {
if (__predict_false(len > dest_len)) {
__fortify_chk_fail("stpncpy: prevented write past end of buffer",
BIONIC_EVENT_STPNCPY_BUFFER_OVERFLOW);
}
return stpncpy(dest, src, len);
}
/*
* __stpncpy_chk2
*
* This is a variant of __stpncpy_chk, but it also checks to make
* sure we don't read beyond the end of "src". The code for this is
* based on the original version of stpncpy, but modified to check
* how much we read from "src" at the end of the copy operation.
*/
extern "C" char* __stpncpy_chk2(char* __restrict dst, const char* __restrict src,
size_t n, size_t dest_len, size_t src_len)
{
if (__predict_false(n > dest_len)) {
__fortify_chk_fail("stpncpy: prevented write past end of buffer",
BIONIC_EVENT_STPNCPY_BUFFER_OVERFLOW);
}
if (n != 0) {
char* d = dst;
const char* s = src;
do {
if ((*d++ = *s++) == 0) {
/* NUL pad the remaining n-1 bytes */
while (--n != 0) {
*d++ = 0;
}
break;
}
} while (--n != 0);
size_t s_copy_len = static_cast<size_t>(s - src);
if (__predict_false(s_copy_len > src_len)) {
__fortify_chk_fail("stpncpy: prevented read past end of buffer", 0);
}
}
return dst;
}
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