10a2301598c207fd1b50015984942fee5e8511593Nick Kralevich/* 20a2301598c207fd1b50015984942fee5e8511593Nick Kralevich * Copyright (C) 2012 The Android Open Source Project 30a2301598c207fd1b50015984942fee5e8511593Nick Kralevich * All rights reserved. 40a2301598c207fd1b50015984942fee5e8511593Nick Kralevich * 50a2301598c207fd1b50015984942fee5e8511593Nick Kralevich * Redistribution and use in source and binary forms, with or without 60a2301598c207fd1b50015984942fee5e8511593Nick Kralevich * modification, are permitted provided that the following conditions 70a2301598c207fd1b50015984942fee5e8511593Nick Kralevich * are met: 80a2301598c207fd1b50015984942fee5e8511593Nick Kralevich * * Redistributions of source code must retain the above copyright 90a2301598c207fd1b50015984942fee5e8511593Nick Kralevich * notice, this list of conditions and the following disclaimer. 100a2301598c207fd1b50015984942fee5e8511593Nick Kralevich * * Redistributions in binary form must reproduce the above copyright 110a2301598c207fd1b50015984942fee5e8511593Nick Kralevich * notice, this list of conditions and the following disclaimer in 120a2301598c207fd1b50015984942fee5e8511593Nick Kralevich * the documentation and/or other materials provided with the 130a2301598c207fd1b50015984942fee5e8511593Nick Kralevich * distribution. 140a2301598c207fd1b50015984942fee5e8511593Nick Kralevich * 150a2301598c207fd1b50015984942fee5e8511593Nick Kralevich * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 160a2301598c207fd1b50015984942fee5e8511593Nick Kralevich * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 170a2301598c207fd1b50015984942fee5e8511593Nick Kralevich * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 180a2301598c207fd1b50015984942fee5e8511593Nick Kralevich * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 190a2301598c207fd1b50015984942fee5e8511593Nick Kralevich * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 200a2301598c207fd1b50015984942fee5e8511593Nick Kralevich * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 210a2301598c207fd1b50015984942fee5e8511593Nick Kralevich * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS 220a2301598c207fd1b50015984942fee5e8511593Nick Kralevich * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 230a2301598c207fd1b50015984942fee5e8511593Nick Kralevich * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 240a2301598c207fd1b50015984942fee5e8511593Nick Kralevich * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 250a2301598c207fd1b50015984942fee5e8511593Nick Kralevich * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 260a2301598c207fd1b50015984942fee5e8511593Nick Kralevich * SUCH DAMAGE. 270a2301598c207fd1b50015984942fee5e8511593Nick Kralevich */ 280a2301598c207fd1b50015984942fee5e8511593Nick Kralevich 290a2301598c207fd1b50015984942fee5e8511593Nick Kralevich#include <string.h> 300a2301598c207fd1b50015984942fee5e8511593Nick Kralevich#include <stdlib.h> 318f2a5a0b40fc82126c691d5c30131d908772aab7Elliott Hughes#include "libc_logging.h" 320a2301598c207fd1b50015984942fee5e8511593Nick Kralevich 330a2301598c207fd1b50015984942fee5e8511593Nick Kralevich/* 340a2301598c207fd1b50015984942fee5e8511593Nick Kralevich * Runtime implementation of __builtin____strncat_chk. 350a2301598c207fd1b50015984942fee5e8511593Nick Kralevich * 360a2301598c207fd1b50015984942fee5e8511593Nick Kralevich * See 370a2301598c207fd1b50015984942fee5e8511593Nick Kralevich * http://gcc.gnu.org/onlinedocs/gcc/Object-Size-Checking.html 380a2301598c207fd1b50015984942fee5e8511593Nick Kralevich * http://gcc.gnu.org/ml/gcc-patches/2004-09/msg02055.html 390a2301598c207fd1b50015984942fee5e8511593Nick Kralevich * for details. 400a2301598c207fd1b50015984942fee5e8511593Nick Kralevich * 410a2301598c207fd1b50015984942fee5e8511593Nick Kralevich * This strncat check is called if _FORTIFY_SOURCE is defined and 420a2301598c207fd1b50015984942fee5e8511593Nick Kralevich * greater than 0. 430a2301598c207fd1b50015984942fee5e8511593Nick Kralevich */ 44cf870199d576bdfc339b7fb016c9f6fe7f2c87edNick Kralevichextern "C" char *__strncat_chk( 45cf870199d576bdfc339b7fb016c9f6fe7f2c87edNick Kralevich char* __restrict dest, 46cf870199d576bdfc339b7fb016c9f6fe7f2c87edNick Kralevich const char* __restrict src, 47cf870199d576bdfc339b7fb016c9f6fe7f2c87edNick Kralevich size_t len, size_t dest_buf_size) 480a2301598c207fd1b50015984942fee5e8511593Nick Kralevich{ 49cf870199d576bdfc339b7fb016c9f6fe7f2c87edNick Kralevich if (len == 0) { 50cf870199d576bdfc339b7fb016c9f6fe7f2c87edNick Kralevich return dest; 510a2301598c207fd1b50015984942fee5e8511593Nick Kralevich } 520a2301598c207fd1b50015984942fee5e8511593Nick Kralevich 53cf870199d576bdfc339b7fb016c9f6fe7f2c87edNick Kralevich size_t dest_len = __strlen_chk(dest, dest_buf_size); 54cf870199d576bdfc339b7fb016c9f6fe7f2c87edNick Kralevich char *d = dest + dest_len; 55cf870199d576bdfc339b7fb016c9f6fe7f2c87edNick Kralevich dest_buf_size -= dest_len; 56cf870199d576bdfc339b7fb016c9f6fe7f2c87edNick Kralevich 57cf870199d576bdfc339b7fb016c9f6fe7f2c87edNick Kralevich while (*src != '\0') { 58cf870199d576bdfc339b7fb016c9f6fe7f2c87edNick Kralevich *d++ = *src++; 59cf870199d576bdfc339b7fb016c9f6fe7f2c87edNick Kralevich len--; dest_buf_size--; 60cf870199d576bdfc339b7fb016c9f6fe7f2c87edNick Kralevich 61cf870199d576bdfc339b7fb016c9f6fe7f2c87edNick Kralevich if (__predict_false(dest_buf_size == 0)) { 62cf870199d576bdfc339b7fb016c9f6fe7f2c87edNick Kralevich __fortify_chk_fail("strncat buffer overflow", 63cf870199d576bdfc339b7fb016c9f6fe7f2c87edNick Kralevich BIONIC_EVENT_STRNCAT_BUFFER_OVERFLOW); 64cf870199d576bdfc339b7fb016c9f6fe7f2c87edNick Kralevich } 6576656afc6dd069fcfda5768e6e54bb85e4e99942Nick Kralevich 66cf870199d576bdfc339b7fb016c9f6fe7f2c87edNick Kralevich if (len == 0) { 67cf870199d576bdfc339b7fb016c9f6fe7f2c87edNick Kralevich break; 68cf870199d576bdfc339b7fb016c9f6fe7f2c87edNick Kralevich } 690a2301598c207fd1b50015984942fee5e8511593Nick Kralevich } 700a2301598c207fd1b50015984942fee5e8511593Nick Kralevich 71cf870199d576bdfc339b7fb016c9f6fe7f2c87edNick Kralevich *d = '\0'; 72cf870199d576bdfc339b7fb016c9f6fe7f2c87edNick Kralevich return dest; 730a2301598c207fd1b50015984942fee5e8511593Nick Kralevich} 74