Differential D3043 Diff 6880 lib/libc/secure/__strncat_chk.c

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lib/libc/secure/__strncat_chk.c

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				/*-
				* Copyright (C) 2012 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.
				*
				* bionic rev: d807b9a12d3e49132b095df3d883618452033b51
				*
				* $FreeBSD$
				*/

				#undef _FORTIFY_SOURCE

				#include <sys/cdefs.h>
				#include <secure/security.h>
				#include <string.h>
				#include <stdlib.h>
				#include "secure/_string.h"

				char *
				__strncat_chk(char __restrict dest, const char __restrict src,
				size_t len, size_t dest_buf_size)
				{
				size_t dest_len;
				char *d;

				if (len == 0)
				return (dest);

				dest_len = __strlen_chk(dest, dest_buf_size);
				d = dest + dest_len;
				dest_buf_size -= dest_len;

				while (*src != '\0') {
				d++ = src++;
				len--;
				dest_buf_size--;

				if (__predict_false(dest_buf_size == 0))
				__fortify_chk_fail(
				"strncat: prevented write past end of buffer");
				if (len == 0)
				break;
				}
				*d = '\0';

				return (dest);
				}