/src/sudo/lib/iolog/iolog_openat.c
Line | Count | Source |
1 | | /* |
2 | | * SPDX-License-Identifier: ISC |
3 | | * |
4 | | * Copyright (c) 2009-2021 Todd C. Miller <Todd.Miller@sudo.ws> |
5 | | * |
6 | | * Permission to use, copy, modify, and distribute this software for any |
7 | | * purpose with or without fee is hereby granted, provided that the above |
8 | | * copyright notice and this permission notice appear in all copies. |
9 | | * |
10 | | * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES |
11 | | * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF |
12 | | * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR |
13 | | * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES |
14 | | * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN |
15 | | * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF |
16 | | * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. |
17 | | */ |
18 | | |
19 | | #include <config.h> |
20 | | |
21 | | #include <sys/stat.h> |
22 | | #include <stdio.h> |
23 | | #include <stdlib.h> |
24 | | #ifdef HAVE_STDBOOL_H |
25 | | # include <stdbool.h> |
26 | | #else |
27 | | # include <compat/stdbool.h> |
28 | | #endif |
29 | | #include <errno.h> |
30 | | #include <fcntl.h> |
31 | | #include <unistd.h> |
32 | | |
33 | | #include <sudo_compat.h> |
34 | | #include <sudo_debug.h> |
35 | | #include <sudo_fatal.h> |
36 | | #include <sudo_gettext.h> |
37 | | #include <sudo_iolog.h> |
38 | | #include <sudo_util.h> |
39 | | |
40 | | /* |
41 | | * Wrapper for openat(2) that sets umask and retries as iolog_uid/iolog_gid |
42 | | * if openat(2) returns EACCES. |
43 | | */ |
44 | | int |
45 | | iolog_openat(int dfd, const char *path, int flags) |
46 | 821 | { |
47 | 821 | const mode_t iolog_filemode = iolog_get_file_mode(); |
48 | 821 | const mode_t iolog_dirmode = iolog_get_dir_mode(); |
49 | 821 | mode_t omask = S_IRWXG|S_IRWXO; |
50 | 821 | int fd; |
51 | 821 | debug_decl(iolog_openat, SUDO_DEBUG_UTIL); |
52 | | |
53 | 821 | if (ISSET(flags, O_CREAT)) { |
54 | | /* umask must not be more restrictive than the file modes. */ |
55 | 0 | omask = umask(ACCESSPERMS & ~(iolog_filemode|iolog_dirmode)); |
56 | 0 | } |
57 | 821 | fd = openat(dfd, path, flags, iolog_filemode); |
58 | 821 | if (fd == -1 && errno == EACCES) { |
59 | | /* Enable write bit if it is missing. */ |
60 | 0 | struct stat sb; |
61 | 0 | if (fstatat(dfd, path, &sb, 0) == 0) { |
62 | 0 | mode_t write_bits = iolog_filemode & (S_IWUSR|S_IWGRP|S_IWOTH); |
63 | 0 | if ((sb.st_mode & write_bits) != write_bits) { |
64 | 0 | if (fchmodat(dfd, path, iolog_filemode, 0) == 0) |
65 | 0 | fd = openat(dfd, path, flags, iolog_filemode); |
66 | 0 | } |
67 | 0 | } |
68 | 0 | } |
69 | 821 | if (fd == -1 && errno == EACCES) { |
70 | | /* Try again as the I/O log owner (for NFS). */ |
71 | 0 | if (iolog_swapids(false)) { |
72 | 0 | fd = openat(dfd, path, flags, iolog_filemode); |
73 | 0 | if (!iolog_swapids(true)) { |
74 | | /* iolog_swapids() warns on error. */ |
75 | 0 | if (fd != -1) { |
76 | 0 | close(fd); |
77 | 0 | fd = -1; |
78 | 0 | } |
79 | 0 | } |
80 | 0 | } |
81 | 0 | } |
82 | 821 | if (ISSET(flags, O_CREAT)) |
83 | 0 | umask(omask); |
84 | 821 | debug_return_int(fd); |
85 | 821 | } |