annotate compat/closefrom.c @ 33:fa93d2ff9c62

Prevent potential division by zero Add safeguard ensuring that there is at least one possible character to generate passwords from in order to exclude the possibility of a division by zero error in rand_uniform.
author Guido Berhoerster <guido+pwm@berhoerster.name>
date Tue, 30 Jul 2019 20:38:08 +0200
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1 /*
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2 * Copyright (C) 2017 Guido Berhoerster <guido+pwm@berhoerster.name>
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3 *
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4 * Permission is hereby granted, free of charge, to any person obtaining
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5 * a copy of this software and associated documentation files (the
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6 * "Software"), to deal in the Software without restriction, including
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7 * without limitation the rights to use, copy, modify, merge, publish,
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8 * distribute, sublicense, and/or sell copies of the Software, and to
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9 * permit persons to whom the Software is furnished to do so, subject to
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10 * the following conditions:
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11 *
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12 * The above copyright notice and this permission notice shall be included
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13 * in all copies or substantial portions of the Software.
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14 *
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15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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16 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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17 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
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18 * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
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19 * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
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20 * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
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21 * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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22 */
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23
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24 #include <errno.h>
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25 #include <fcntl.h>
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26 #include <unistd.h>
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27
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28 int
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29 closefrom(int fd_min)
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30 {
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31 #ifdef F_CLOSEM
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32 return fcntl(fd_min, F_CLOSEM, 0);
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33 #else /* !F_CLOSEM */
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34 int fd_max;
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35 int fd;
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36
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37 fd_max = sysconf(_SC_OPEN_MAX);
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38 for (fd = fd_min; fd < fd_max; fd++) {
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39 if ((close(fd) < 0) && (errno != EBADF)) {
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40 return (-1);
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41 }
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42 }
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43
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44 return (0);
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45 #endif /* !F_CLOSEM */
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46 }