a89864a20b
I'll need at least one more pass, because there's some upstream code lurking in libc/bionic, but this is still a step in the right direction. Change-Id: I55927315972da8327ae01c5240ed587db17e8462
72 lines
2.6 KiB
C
72 lines
2.6 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 <private/logd.h>
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#include <safe_iop.h>
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/*
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* Runtime implementation of __builtin____strncat_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 strncat check is called if _FORTIFY_SOURCE is defined and
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* greater than 0.
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*/
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char *__strncat_chk (char *dest, const char *src,
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size_t len, size_t dest_buf_size)
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{
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// TODO: optimize so we don't scan src/dest twice.
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size_t dest_len = strlen(dest);
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size_t src_len = strlen(src);
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if (src_len > len) {
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src_len = len;
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}
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size_t sum;
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// sum = src_len + dest_len + 1 (with overflow protection)
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if (!safe_add3(&sum, src_len, dest_len, 1U)) {
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__libc_android_log_print(ANDROID_LOG_FATAL, "libc",
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"*** strncat integer overflow detected ***\n");
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__libc_android_log_event_uid(BIONIC_EVENT_STRNCAT_INTEGER_OVERFLOW);
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abort();
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}
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if (sum > dest_buf_size) {
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__libc_android_log_print(ANDROID_LOG_FATAL, "libc",
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"*** strncat buffer overflow detected ***\n");
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__libc_android_log_event_uid(BIONIC_EVENT_STRNCAT_BUFFER_OVERFLOW);
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abort();
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}
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return strncat(dest, src, len);
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}
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