1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Copyright (c) 2022 FUJITSU LIMITED. All rights reserved.
4 * Author: Yang Xu <[email protected]>
5 */
6
7 /*\
8 * [Description]
9 *
10 * Check setgid strip logic whether works correctly when creating tmpfile under
11 * filesystem without POSIX ACL supported(by using noacl mount option). Test it
12 * with umask S_IXGRP and also check file mode whether has filtered S_IXGRP.
13 *
14 * Fixed in:
15 *
16 * commit ac6800e279a22b28f4fc21439843025a0d5bf03e
17 * Author: Yang Xu <[email protected]>
18 * Date: Thu July 14 14:11:26 2022 +0800
19 *
20 * fs: Add missing umask strip in vfs_tmpfile
21 *
22 * The most code is pasted form creat09.c.
23 */
24
25 #define _GNU_SOURCE
26 #include <stdlib.h>
27 #include <sys/types.h>
28 #include <pwd.h>
29 #include <sys/mount.h>
30 #include <unistd.h>
31 #include <stdio.h>
32 #include "tst_test.h"
33 #include "lapi/fcntl.h"
34 #include "tst_uid.h"
35 #include "tst_safe_file_at.h"
36
37 #define MODE_RWX 0777
38 #define MODE_SGID (S_ISGID|0777)
39 #define MNTPOINT "mntpoint"
40 #define WORKDIR MNTPOINT "/testdir"
41 #define OPEN_FILE "open.tmp"
42
43 static gid_t free_gid;
44 static int tmpfile_fd = -1, dir_fd = -1, mount_flag;
45 static struct passwd *ltpuser;
46
do_mount(const char * source,const char * target,const char * filesystemtype,unsigned long mountflags,const void * data)47 static void do_mount(const char *source, const char *target,
48 const char *filesystemtype, unsigned long mountflags,
49 const void *data)
50 {
51 TEST(mount(source, target, filesystemtype, mountflags, data));
52
53 if (TST_RET == -1 && TST_ERR == EINVAL)
54 tst_brk(TCONF, "Kernel does not support noacl feature");
55
56 if (TST_RET == -1) {
57 tst_brk(TBROK | TTERRNO, "mount(%s, %s, %s, %lu, %p) failed",
58 source, target, filesystemtype, mountflags, data);
59 }
60
61 if (TST_RET)
62 tst_brk(TBROK, "Invalid mount return value %ld", TST_RET);
63
64 mount_flag = 1;
65 }
66
open_tmpfile_supported(int dirfd)67 static void open_tmpfile_supported(int dirfd)
68 {
69 TEST(openat(dirfd, ".", O_TMPFILE | O_RDWR, S_IXGRP | S_ISGID));
70
71 if (TST_RET == -1) {
72 if (errno == ENOTSUP)
73 tst_brk(TCONF, "fs doesn't support O_TMPFILE");
74 else
75 tst_brk(TBROK | TTERRNO, "openat(%d, O_TMPFILE) failed", dirfd);
76 }
77
78 if (TST_RET < 0)
79 tst_brk(TBROK, "Invalid openat return value %ld", TST_RET);
80
81 SAFE_CLOSE(TST_RET);
82 }
83
setup(void)84 static void setup(void)
85 {
86 struct stat buf;
87
88 ltpuser = SAFE_GETPWNAM("nobody");
89
90 do_mount(tst_device->dev, MNTPOINT, tst_device->fs_type, 0, "noacl");
91
92 tst_res(TINFO, "User nobody: uid = %d, gid = %d", (int)ltpuser->pw_uid,
93 (int)ltpuser->pw_gid);
94 free_gid = tst_get_free_gid(ltpuser->pw_gid);
95
96 /* Create directories and set permissions */
97 SAFE_MKDIR(WORKDIR, MODE_RWX);
98 dir_fd = SAFE_OPEN(WORKDIR, O_RDONLY, O_DIRECTORY);
99 open_tmpfile_supported(dir_fd);
100
101 SAFE_CHOWN(WORKDIR, ltpuser->pw_uid, free_gid);
102 SAFE_CHMOD(WORKDIR, MODE_SGID);
103 SAFE_STAT(WORKDIR, &buf);
104
105 if (!(buf.st_mode & S_ISGID))
106 tst_brk(TBROK, "%s: Setgid bit not set", WORKDIR);
107
108 if (buf.st_gid != free_gid) {
109 tst_brk(TBROK, "%s: Incorrect group, %u != %u", WORKDIR,
110 buf.st_gid, free_gid);
111 }
112
113 /* Switch user */
114 SAFE_SETGID(ltpuser->pw_gid);
115 SAFE_SETREUID(-1, ltpuser->pw_uid);
116 }
117
file_test(int dfd,const char * path,int flags)118 static void file_test(int dfd, const char *path, int flags)
119 {
120 struct stat buf;
121
122 SAFE_FSTATAT(dfd, path, &buf, flags);
123
124 TST_EXP_EQ_LI(buf.st_gid, free_gid);
125
126 if (buf.st_mode & S_ISGID)
127 tst_res(TFAIL, "%s: Setgid bit is set", path);
128 else
129 tst_res(TPASS, "%s: Setgid bit not set", path);
130
131 if (buf.st_mode & S_IXGRP)
132 tst_res(TFAIL, "%s: S_IXGRP bit is set", path);
133 else
134 tst_res(TPASS, "%s: S_IXGRP bit is not set", path);
135 }
136
run(void)137 static void run(void)
138 {
139 char path[PATH_MAX];
140
141 umask(S_IXGRP);
142 tmpfile_fd = SAFE_OPENAT(dir_fd, ".", O_TMPFILE | O_RDWR, MODE_SGID);
143 snprintf(path, PATH_MAX, "/proc/self/fd/%d", tmpfile_fd);
144 SAFE_LINKAT(AT_FDCWD, path, dir_fd, OPEN_FILE, AT_SYMLINK_FOLLOW);
145 file_test(dir_fd, OPEN_FILE, 0);
146 SAFE_CLOSE(tmpfile_fd);
147 /* Cleanup between loops */
148 tst_purge_dir(WORKDIR);
149 }
150
cleanup(void)151 static void cleanup(void)
152 {
153 SAFE_SETREUID(-1, 0);
154
155 if (tmpfile_fd >= 0)
156 SAFE_CLOSE(tmpfile_fd);
157 if (dir_fd >= 0)
158 SAFE_CLOSE(dir_fd);
159 if (mount_flag && tst_umount(MNTPOINT))
160 tst_res(TWARN | TERRNO, "umount(%s)", MNTPOINT);
161 }
162
163 static struct tst_test test = {
164 .test_all = run,
165 .setup = setup,
166 .cleanup = cleanup,
167 .needs_root = 1,
168 .all_filesystems = 1,
169 .format_device = 1,
170 .mntpoint = MNTPOINT,
171 .skip_filesystems = (const char*[]) {
172 "exfat",
173 "ntfs",
174 "vfat",
175 NULL
176 },
177 .tags = (const struct tst_tag[]) {
178 {"linux-git", "ac6800e279a2"},
179 {"linux-git", "426b4ca2d6a5"},
180 {}
181 },
182 };
183