bionic/libc/bionic/__strlcpy_chk.cpp
Nick Kralevich e2617290fc FORTIFY_SOURCE: emphasize prevention in error messages.
FORTIFY_SOURCE prevents buffer overflows from occurring.
However, the error message often implies that we only
detect it, not prevent it.

Bring more clarity to the error messages by emphasizing
prevention over detection.

Change-Id: I5f3e1478673bdfc589e6cc4199fce8e52e197a24
2013-10-04 08:57:17 -07:00

54 lines
2.1 KiB
C++

/*
* 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.
*/
#include <string.h>
#include <stdlib.h>
#include "libc_logging.h"
/*
* __strlcpy_chk. Called in place of strlcpy() when we know the
* size of the buffer we're writing into.
*
* 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 strlcpy check is called if _FORTIFY_SOURCE is defined and
* greater than 0.
*/
extern "C" size_t __strlcpy_chk(char *dest, const char *src,
size_t supplied_size, size_t dest_len_from_compiler)
{
if (__predict_false(supplied_size > dest_len_from_compiler)) {
__fortify_chk_fail("strlcpy buffer overflow prevented", 0);
}
return strlcpy(dest, src, supplied_size);
}