1950a58e24d1019eb9d814dbb16f111a6b61e3f23Christopher Ferris/* 2950a58e24d1019eb9d814dbb16f111a6b61e3f23Christopher Ferris * Copyright (C) 2014 The Android Open Source Project 3950a58e24d1019eb9d814dbb16f111a6b61e3f23Christopher Ferris * All rights reserved. 4950a58e24d1019eb9d814dbb16f111a6b61e3f23Christopher Ferris * 5950a58e24d1019eb9d814dbb16f111a6b61e3f23Christopher Ferris * Redistribution and use in source and binary forms, with or without 6950a58e24d1019eb9d814dbb16f111a6b61e3f23Christopher Ferris * modification, are permitted provided that the following conditions 7950a58e24d1019eb9d814dbb16f111a6b61e3f23Christopher Ferris * are met: 8950a58e24d1019eb9d814dbb16f111a6b61e3f23Christopher Ferris * * Redistributions of source code must retain the above copyright 9950a58e24d1019eb9d814dbb16f111a6b61e3f23Christopher Ferris * notice, this list of conditions and the following disclaimer. 10950a58e24d1019eb9d814dbb16f111a6b61e3f23Christopher Ferris * * Redistributions in binary form must reproduce the above copyright 11950a58e24d1019eb9d814dbb16f111a6b61e3f23Christopher Ferris * notice, this list of conditions and the following disclaimer in 12950a58e24d1019eb9d814dbb16f111a6b61e3f23Christopher Ferris * the documentation and/or other materials provided with the 13950a58e24d1019eb9d814dbb16f111a6b61e3f23Christopher Ferris * distribution. 14950a58e24d1019eb9d814dbb16f111a6b61e3f23Christopher Ferris * 15950a58e24d1019eb9d814dbb16f111a6b61e3f23Christopher Ferris * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 16950a58e24d1019eb9d814dbb16f111a6b61e3f23Christopher Ferris * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 17950a58e24d1019eb9d814dbb16f111a6b61e3f23Christopher Ferris * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 18950a58e24d1019eb9d814dbb16f111a6b61e3f23Christopher Ferris * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 19950a58e24d1019eb9d814dbb16f111a6b61e3f23Christopher Ferris * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 20950a58e24d1019eb9d814dbb16f111a6b61e3f23Christopher Ferris * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 21950a58e24d1019eb9d814dbb16f111a6b61e3f23Christopher Ferris * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS 22950a58e24d1019eb9d814dbb16f111a6b61e3f23Christopher Ferris * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 23950a58e24d1019eb9d814dbb16f111a6b61e3f23Christopher Ferris * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 24950a58e24d1019eb9d814dbb16f111a6b61e3f23Christopher Ferris * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 25950a58e24d1019eb9d814dbb16f111a6b61e3f23Christopher Ferris * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26950a58e24d1019eb9d814dbb16f111a6b61e3f23Christopher Ferris * SUCH DAMAGE. 27950a58e24d1019eb9d814dbb16f111a6b61e3f23Christopher Ferris */ 28950a58e24d1019eb9d814dbb16f111a6b61e3f23Christopher Ferris 29950a58e24d1019eb9d814dbb16f111a6b61e3f23Christopher Ferris#undef _FORTIFY_SOURCE 30950a58e24d1019eb9d814dbb16f111a6b61e3f23Christopher Ferris 31950a58e24d1019eb9d814dbb16f111a6b61e3f23Christopher Ferris#include <string.h> 32950a58e24d1019eb9d814dbb16f111a6b61e3f23Christopher Ferris#include <stdlib.h> 33950a58e24d1019eb9d814dbb16f111a6b61e3f23Christopher Ferris#include "private/libc_logging.h" 34950a58e24d1019eb9d814dbb16f111a6b61e3f23Christopher Ferris 35950a58e24d1019eb9d814dbb16f111a6b61e3f23Christopher Ferris/* 36950a58e24d1019eb9d814dbb16f111a6b61e3f23Christopher Ferris * Runtime implementation of __builtin____stpncpy_chk. 37950a58e24d1019eb9d814dbb16f111a6b61e3f23Christopher Ferris * 38950a58e24d1019eb9d814dbb16f111a6b61e3f23Christopher Ferris * See 39950a58e24d1019eb9d814dbb16f111a6b61e3f23Christopher Ferris * http://gcc.gnu.org/onlinedocs/gcc/Object-Size-Checking.html 40950a58e24d1019eb9d814dbb16f111a6b61e3f23Christopher Ferris * http://gcc.gnu.org/ml/gcc-patches/2004-09/msg02055.html 41950a58e24d1019eb9d814dbb16f111a6b61e3f23Christopher Ferris * for details. 42950a58e24d1019eb9d814dbb16f111a6b61e3f23Christopher Ferris * 43950a58e24d1019eb9d814dbb16f111a6b61e3f23Christopher Ferris * This stpncpy check is called if _FORTIFY_SOURCE is defined and 44950a58e24d1019eb9d814dbb16f111a6b61e3f23Christopher Ferris * greater than 0. 45950a58e24d1019eb9d814dbb16f111a6b61e3f23Christopher Ferris */ 46950a58e24d1019eb9d814dbb16f111a6b61e3f23Christopher Ferrisextern "C" char* __stpncpy_chk(char* __restrict dest, const char* __restrict src, 47950a58e24d1019eb9d814dbb16f111a6b61e3f23Christopher Ferris size_t len, size_t dest_len) { 48950a58e24d1019eb9d814dbb16f111a6b61e3f23Christopher Ferris if (__predict_false(len > dest_len)) { 49950a58e24d1019eb9d814dbb16f111a6b61e3f23Christopher Ferris __fortify_chk_fail("stpncpy: prevented write past end of buffer", 50950a58e24d1019eb9d814dbb16f111a6b61e3f23Christopher Ferris BIONIC_EVENT_STPNCPY_BUFFER_OVERFLOW); 51950a58e24d1019eb9d814dbb16f111a6b61e3f23Christopher Ferris } 52950a58e24d1019eb9d814dbb16f111a6b61e3f23Christopher Ferris 53950a58e24d1019eb9d814dbb16f111a6b61e3f23Christopher Ferris return stpncpy(dest, src, len); 54950a58e24d1019eb9d814dbb16f111a6b61e3f23Christopher Ferris} 55950a58e24d1019eb9d814dbb16f111a6b61e3f23Christopher Ferris 56950a58e24d1019eb9d814dbb16f111a6b61e3f23Christopher Ferris/* 57950a58e24d1019eb9d814dbb16f111a6b61e3f23Christopher Ferris * __stpncpy_chk2 58950a58e24d1019eb9d814dbb16f111a6b61e3f23Christopher Ferris * 59950a58e24d1019eb9d814dbb16f111a6b61e3f23Christopher Ferris * This is a variant of __stpncpy_chk, but it also checks to make 60950a58e24d1019eb9d814dbb16f111a6b61e3f23Christopher Ferris * sure we don't read beyond the end of "src". The code for this is 61950a58e24d1019eb9d814dbb16f111a6b61e3f23Christopher Ferris * based on the original version of stpncpy, but modified to check 62950a58e24d1019eb9d814dbb16f111a6b61e3f23Christopher Ferris * how much we read from "src" at the end of the copy operation. 63950a58e24d1019eb9d814dbb16f111a6b61e3f23Christopher Ferris */ 64950a58e24d1019eb9d814dbb16f111a6b61e3f23Christopher Ferrisextern "C" char* __stpncpy_chk2(char* __restrict dst, const char* __restrict src, 65950a58e24d1019eb9d814dbb16f111a6b61e3f23Christopher Ferris size_t n, size_t dest_len, size_t src_len) 66950a58e24d1019eb9d814dbb16f111a6b61e3f23Christopher Ferris{ 67950a58e24d1019eb9d814dbb16f111a6b61e3f23Christopher Ferris if (__predict_false(n > dest_len)) { 68950a58e24d1019eb9d814dbb16f111a6b61e3f23Christopher Ferris __fortify_chk_fail("stpncpy: prevented write past end of buffer", 69950a58e24d1019eb9d814dbb16f111a6b61e3f23Christopher Ferris BIONIC_EVENT_STPNCPY_BUFFER_OVERFLOW); 70950a58e24d1019eb9d814dbb16f111a6b61e3f23Christopher Ferris } 71950a58e24d1019eb9d814dbb16f111a6b61e3f23Christopher Ferris if (n != 0) { 72950a58e24d1019eb9d814dbb16f111a6b61e3f23Christopher Ferris char* d = dst; 73950a58e24d1019eb9d814dbb16f111a6b61e3f23Christopher Ferris const char* s = src; 74950a58e24d1019eb9d814dbb16f111a6b61e3f23Christopher Ferris 75950a58e24d1019eb9d814dbb16f111a6b61e3f23Christopher Ferris do { 76950a58e24d1019eb9d814dbb16f111a6b61e3f23Christopher Ferris if ((*d++ = *s++) == 0) { 77950a58e24d1019eb9d814dbb16f111a6b61e3f23Christopher Ferris /* NUL pad the remaining n-1 bytes */ 78950a58e24d1019eb9d814dbb16f111a6b61e3f23Christopher Ferris while (--n != 0) { 79950a58e24d1019eb9d814dbb16f111a6b61e3f23Christopher Ferris *d++ = 0; 80950a58e24d1019eb9d814dbb16f111a6b61e3f23Christopher Ferris } 81950a58e24d1019eb9d814dbb16f111a6b61e3f23Christopher Ferris break; 82950a58e24d1019eb9d814dbb16f111a6b61e3f23Christopher Ferris } 83950a58e24d1019eb9d814dbb16f111a6b61e3f23Christopher Ferris } while (--n != 0); 84950a58e24d1019eb9d814dbb16f111a6b61e3f23Christopher Ferris 85950a58e24d1019eb9d814dbb16f111a6b61e3f23Christopher Ferris size_t s_copy_len = static_cast<size_t>(s - src); 86950a58e24d1019eb9d814dbb16f111a6b61e3f23Christopher Ferris if (__predict_false(s_copy_len > src_len)) { 87950a58e24d1019eb9d814dbb16f111a6b61e3f23Christopher Ferris __fortify_chk_fail("stpncpy: prevented read past end of buffer", 0); 88950a58e24d1019eb9d814dbb16f111a6b61e3f23Christopher Ferris } 89950a58e24d1019eb9d814dbb16f111a6b61e3f23Christopher Ferris } 90950a58e24d1019eb9d814dbb16f111a6b61e3f23Christopher Ferris 91950a58e24d1019eb9d814dbb16f111a6b61e3f23Christopher Ferris return dst; 92950a58e24d1019eb9d814dbb16f111a6b61e3f23Christopher Ferris} 93