1 /* 2 * Copyright (C) 2012 The Android Open Source Project 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * * Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * * Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in 12 * the documentation and/or other materials provided with the 13 * distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 16 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 17 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 18 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 19 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 21 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS 22 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 23 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 24 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 25 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 */ 28 29 #include <string.h> 30 #include <stdlib.h> 31 #include "libc_logging.h" 32 33 /* 34 * Runtime implementation of __builtin____strcat_chk. 35 * 36 * See 37 * http://gcc.gnu.org/onlinedocs/gcc/Object-Size-Checking.html 38 * http://gcc.gnu.org/ml/gcc-patches/2004-09/msg02055.html 39 * for details. 40 * 41 * This strcat check is called if _FORTIFY_SOURCE is defined and 42 * greater than 0. 43 */ 44 extern "C" char* __strcat_chk( 45 char* __restrict dest, 46 const char* __restrict src, 47 size_t dest_buf_size) 48 { 49 char* save = dest; 50 size_t dest_len = __strlen_chk(dest, dest_buf_size); 51 52 dest += dest_len; 53 dest_buf_size -= dest_len; 54 55 while ((*dest++ = *src++) != '\0') { 56 dest_buf_size--; 57 if (__predict_false(dest_buf_size == 0)) { 58 __fortify_chk_fail("strcat buffer overflow", 59 BIONIC_EVENT_STRCAT_BUFFER_OVERFLOW); 60 } 61 } 62 63 return save; 64 } 65