Home | History | Annotate | Download | only in bionic
      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