cf870199d5
__strcat_chk and __strncat_chk are slightly inefficient, because they end up traversing over the same memory region two times. This change optimizes __strcat_chk / __strncat_chk so they only access the memory once. Although I haven't benchmarked these changes, it should improve the performance of these functions. __strlen_chk - expose this function, even if -D_FORTIFY_SOURCE isn't defined. This is needed to compile libc itself without -D_FORTIFY_SOURCE. Change-Id: Id2c70dff55a276b47c59db27a03734d659f84b74
64 lines
2.3 KiB
C++
64 lines
2.3 KiB
C++
/*
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* Copyright (C) 2012 The Android Open Source Project
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* * Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* * Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
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* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <string.h>
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#include <stdlib.h>
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#include "libc_logging.h"
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/*
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* Runtime implementation of __builtin____strcat_chk.
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*
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* See
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* http://gcc.gnu.org/onlinedocs/gcc/Object-Size-Checking.html
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* http://gcc.gnu.org/ml/gcc-patches/2004-09/msg02055.html
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* for details.
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*
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* This strcat check is called if _FORTIFY_SOURCE is defined and
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* greater than 0.
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*/
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extern "C" char* __strcat_chk(
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char* __restrict dest,
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const char* __restrict src,
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size_t dest_buf_size)
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{
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char* save = dest;
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size_t dest_len = __strlen_chk(dest, dest_buf_size);
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dest += dest_len;
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dest_buf_size -= dest_len;
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while ((*dest++ = *src++) != '\0') {
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dest_buf_size--;
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if (__predict_false(dest_buf_size == 0)) {
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__fortify_chk_fail("strcat buffer overflow",
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BIONIC_EVENT_STRCAT_BUFFER_OVERFLOW);
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}
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}
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return save;
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}
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