mirror of https://github.com/sudo-project/sudo.git
128 lines
3.5 KiB
C
128 lines
3.5 KiB
C
/*
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* SPDX-License-Identifier: ISC
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*
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* Copyright (c) 2009-2021 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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#include <stdio.h>
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#include <stdlib.h>
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#ifdef HAVE_STDBOOL_H
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# include <stdbool.h>
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#else
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# include <compat/stdbool.h>
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#endif
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#include <errno.h>
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#include <fcntl.h>
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#include <time.h>
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#include <unistd.h>
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#include <sudo_compat.h>
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#include <sudo_debug.h>
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#include <sudo_iolog.h>
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#include <sudo_util.h>
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static unsigned char const gzip_magic[2] = {0x1f, 0x8b};
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/*
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* Open the specified I/O log file and store in iol.
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* Stores the open file handle which has the close-on-exec flag set.
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*/
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bool
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iolog_open(struct iolog_file *iol, int dfd, int iofd, const char *mode)
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{
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int flags;
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const char *file;
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unsigned char magic[2];
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const uid_t iolog_uid = iolog_get_uid();
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const gid_t iolog_gid = iolog_get_gid();
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debug_decl(iolog_open, SUDO_DEBUG_UTIL);
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if (mode[0] == 'r') {
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flags = mode[1] == '+' ? O_RDWR : O_RDONLY;
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} else if (mode[0] == 'w') {
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flags = O_CREAT|O_TRUNC;
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flags |= mode[1] == '+' ? O_RDWR : O_WRONLY;
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} else {
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sudo_debug_printf(SUDO_DEBUG_ERROR,
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"%s: invalid I/O mode %s", __func__, mode);
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debug_return_bool(false);
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}
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if ((file = iolog_fd_to_name(iofd)) == NULL) {
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sudo_debug_printf(SUDO_DEBUG_ERROR,
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"%s: invalid iofd %d", __func__, iofd);
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debug_return_bool(false);
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}
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iol->writable = false;
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iol->compressed = false;
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if (iol->enabled) {
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int fd = iolog_openat(dfd, file, flags);
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if (fd != -1) {
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if (*mode == 'w') {
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if (fchown(fd, iolog_uid, iolog_gid) != 0) {
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sudo_debug_printf(SUDO_DEBUG_ERROR|SUDO_DEBUG_ERRNO,
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"%s: unable to fchown %d:%d %s", __func__,
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(int)iolog_uid, (int)iolog_gid, file);
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}
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iol->compressed = iolog_get_compress();
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} else {
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/* check for gzip magic number */
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if (pread(fd, magic, sizeof(magic), 0) == ssizeof(magic)) {
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if (magic[0] == gzip_magic[0] && magic[1] == gzip_magic[1])
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iol->compressed = true;
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}
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}
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if (fcntl(fd, F_SETFD, FD_CLOEXEC) != -1) {
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#ifdef HAVE_ZLIB_H
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if (iol->compressed)
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iol->fd.g = gzdopen(fd, mode);
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else
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#endif
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iol->fd.f = fdopen(fd, mode);
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}
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if (iol->fd.v != NULL) {
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switch ((flags & O_ACCMODE)) {
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case O_WRONLY:
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case O_RDWR:
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iol->writable = true;
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break;
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}
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} else {
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int save_errno = errno;
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close(fd);
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errno = save_errno;
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fd = -1;
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}
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}
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if (fd == -1) {
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iol->enabled = false;
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debug_return_bool(false);
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}
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} else {
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if (*mode == 'w') {
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/* Remove old log file in case we recycled sequence numbers. */
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(void)unlinkat(dfd, file, 0);
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}
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}
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debug_return_bool(true);
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}
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