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/*
* SPDX-License-Identifier: ISC
*
* Copyright (c) 2009-2021 Todd C. Miller <Todd.Miller@sudo.ws>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
/*
* This is an open source non-commercial project. Dear PVS-Studio, please check it.
* PVS-Studio Static Code Analyzer for C, C++ and C#: http://www.viva64.com
*/
#include <config.h>
#include <sys/stat.h>
#include <stdio.h>
#include <stdlib.h>
#ifdef HAVE_STDBOOL_H
# include <stdbool.h>
#else
# include <compat/stdbool.h>
#endif
#include <errno.h>
#include <fcntl.h>
#include <unistd.h>
#include <sudo_compat.h>
#include <sudo_debug.h>
#include <sudo_fatal.h>
#include <sudo_gettext.h>
#include <sudo_iolog.h>
#include <sudo_util.h>
/*
* Wrapper for openat(2) that sets umask and retries as iolog_uid/iolog_gid
* if openat(2) returns EACCES.
*/
int
iolog_openat(int dfd, const char *path, int flags)
{
const mode_t iolog_filemode = iolog_get_file_mode();
const mode_t iolog_dirmode = iolog_get_dir_mode();
mode_t omask = S_IRWXG|S_IRWXO;
int fd;
debug_decl(iolog_openat, SUDO_DEBUG_UTIL);
if (ISSET(flags, O_CREAT)) {
/* umask must not be more restrictive than the file modes. */
omask = umask(ACCESSPERMS & ~(iolog_filemode|iolog_dirmode));
}
fd = openat(dfd, path, flags, iolog_filemode);
if (fd == -1 && errno == EACCES) {
/* Enable write bit if it is missing. */
struct stat sb;
if (fstatat(dfd, path, &sb, 0) == 0) {
mode_t write_bits = iolog_filemode & (S_IWUSR|S_IWGRP|S_IWOTH);
if ((sb.st_mode & write_bits) != write_bits) {
if (fchmodat(dfd, path, iolog_filemode, 0) == 0)
fd = openat(dfd, path, flags, iolog_filemode);
}
}
}
if (fd == -1 && errno == EACCES) {
/* Try again as the I/O log owner (for NFS). */
if (iolog_swapids(false)) {
fd = openat(dfd, path, flags, iolog_filemode);
if (!iolog_swapids(true)) {
/* iolog_swapids() warns on error. */
if (fd != -1) {
close(fd);
fd = -1;
}
}
}
}
if (ISSET(flags, O_CREAT))
umask(omask);
debug_return_int(fd);
}
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