146 lines
3.8 KiB
C
146 lines
3.8 KiB
C
/*
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* SPDX-License-Identifier: ISC
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*
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* Copyright (c) 2004-2005, 2007, 2010, 2012-2015, 2017-2018
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* Todd C. Miller <Todd.Miller@sudo.ws>
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*
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* Permission to use, copy, modify, and distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*/
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/*
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* This is an open source non-commercial project. Dear PVS-Studio, please check it.
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* PVS-Studio Static Code Analyzer for C, C++ and C#: http://www.viva64.com
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*/
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#include <config.h>
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#ifndef HAVE_CLOSEFROM
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#include <sys/types.h>
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#include <unistd.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <fcntl.h>
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#include <limits.h>
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#ifdef HAVE_PSTAT_GETPROC
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# include <sys/pstat.h>
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#else
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# include <dirent.h>
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#endif
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#include "sudo_compat.h"
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#include "sudo_util.h"
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#include "pathnames.h"
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#ifndef OPEN_MAX
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# define OPEN_MAX 256
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#endif
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/*
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* Close all file descriptors greater than or equal to lowfd.
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* This is the expensive (fallback) method.
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*/
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static void
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closefrom_fallback(int lowfd)
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{
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long fd, maxfd;
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/*
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* Fall back on sysconf(_SC_OPEN_MAX). This is equivalent to
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* checking the RLIMIT_NOFILE soft limit. It is possible for
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* there to be open file descriptors past this limit but there's
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* not much we can do about that since the hard limit may be
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* RLIM_INFINITY (LLONG_MAX or ULLONG_MAX on modern systems).
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*/
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maxfd = sysconf(_SC_OPEN_MAX);
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if (maxfd < OPEN_MAX)
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maxfd = OPEN_MAX;
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/* Make sure we didn't get RLIM_INFINITY as the upper limit. */
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if (maxfd > INT_MAX)
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maxfd = INT_MAX;
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for (fd = lowfd; fd < maxfd; fd++) {
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#ifdef __APPLE__
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/* Avoid potential libdispatch crash when we close its fds. */
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(void) fcntl((int) fd, F_SETFD, FD_CLOEXEC);
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#else
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(void) close((int) fd);
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#endif
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}
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}
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/*
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* Close all file descriptors greater than or equal to lowfd.
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* We try the fast way first, falling back on the slow method.
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*/
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void
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sudo_closefrom(int lowfd)
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{
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#if defined(HAVE_PSTAT_GETPROC)
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struct pst_status pstat;
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#elif defined(HAVE_DIRFD)
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const char *path;
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DIR *dirp;
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#endif
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/* Try the fast method first, if possible. */
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#if defined(HAVE_FCNTL_CLOSEM)
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if (fcntl(lowfd, F_CLOSEM, 0) != -1)
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return;
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#endif
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#if defined(HAVE_PSTAT_GETPROC)
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/*
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* EOVERFLOW is not a fatal error for the fields we use.
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* See the "EOVERFLOW Error" section of pstat_getvminfo(3).
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*/
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if (pstat_getproc(&pstat, sizeof(pstat), 0, getpid()) != -1 ||
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errno == EOVERFLOW) {
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int fd;
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for (fd = lowfd; fd <= pstat.pst_highestfd; fd++)
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(void) close(fd);
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return;
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}
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#elif defined(HAVE_DIRFD)
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/* Use /proc/self/fd (or /dev/fd on macOS) if it exists. */
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# ifdef __APPLE__
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path = _PATH_DEV "fd";
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# else
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path = "/proc/self/fd";
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# endif
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if ((dirp = opendir(path)) != NULL) {
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struct dirent *dent;
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while ((dent = readdir(dirp)) != NULL) {
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const char *errstr;
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int fd = sudo_strtonum(dent->d_name, lowfd, INT_MAX, &errstr);
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if (errstr == NULL && fd != dirfd(dirp)) {
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# ifdef __APPLE__
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/* Avoid potential libdispatch crash when we close its fds. */
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(void) fcntl(fd, F_SETFD, FD_CLOEXEC);
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# else
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(void) close(fd);
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# endif
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}
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}
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(void) closedir(dirp);
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return;
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}
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#endif /* HAVE_DIRFD */
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/* Do things the slow way. */
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closefrom_fallback(lowfd);
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}
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#endif /* HAVE_CLOSEFROM */
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