93501d3ab8
This change detects programs reading beyond the end of "src" when calling strncpy. Change-Id: Ie1b42de923385d62552b22c27b2d4713ab77ee03
92 lines
3.1 KiB
C++
92 lines
3.1 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____strncpy_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 strncpy 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* __strncpy_chk(char* __restrict dest, const char* __restrict src,
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size_t len, size_t dest_len)
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{
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if (__predict_false(len > dest_len)) {
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__fortify_chk_fail("strncpy dest buffer overflow",
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BIONIC_EVENT_STRNCPY_BUFFER_OVERFLOW);
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}
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return strncpy(dest, src, len);
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}
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/*
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* __strncpy_chk2
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*
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* This is a variant of __strncpy_chk, but it also checks to make
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* sure we don't read beyond the end of "src". The code for this is
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* based on the original version of strncpy, but modified to check
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* how much we read from "src" at the end of the copy operation.
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*/
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extern "C" char* __strncpy_chk2(char* __restrict dst, const char* __restrict src,
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size_t n, size_t dest_len, size_t src_len)
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{
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if (__predict_false(n > dest_len)) {
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__fortify_chk_fail("strncpy dest buffer overflow",
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BIONIC_EVENT_STRNCPY_BUFFER_OVERFLOW);
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}
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if (n != 0) {
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char* d = dst;
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const char* s = src;
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do {
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if ((*d++ = *s++) == 0) {
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/* NUL pad the remaining n-1 bytes */
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while (--n != 0) {
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*d++ = 0;
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}
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break;
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}
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} while (--n != 0);
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size_t s_copy_len = static_cast<size_t>(s - src);
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if (__predict_false(s_copy_len > src_len)) {
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__fortify_chk_fail("strncpy read beyond end of src buffer", 0);
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}
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}
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return dst;
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}
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