1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Copyright (c) International Business Machines Corp., 2001
4 * 07/2001 Ported by Wayne Boyer
5 * Copyright (c) 2019 SUSE LLC <mdoucha@suse.cz>
6 */
7
8 /*
9 * Check that the chdir() syscall returns correct value and error code
10 * in various situations when called with root privileges
11 */
12
13 #include <stdio.h>
14 #include <stdlib.h>
15 #include <sys/types.h>
16 #include <unistd.h>
17 #include <pwd.h>
18
19 #include "tst_test.h"
20
21 #define MNTPOINT "mntpoint"
22
23 #define FILE_NAME "testfile"
24 #define DIR_NAME "subdir"
25 #define BLOCKED_NAME "keep_out"
26 #define LINK_NAME1 "symloop"
27 #define LINK_NAME2 "symloop2"
28 #define TESTUSER "nobody"
29
30 static char *workdir;
31 static int skip_symlinks, skip_blocked;
32 static struct passwd *ltpuser;
33
34 static struct test_case {
35 const char *name;
36 int root_ret, root_err, nobody_ret, nobody_err;
37 } testcase_list[] = {
38 {FILE_NAME, -1, ENOTDIR, -1, ENOTDIR},
39 {BLOCKED_NAME, 0, 0, -1, EACCES},
40 {DIR_NAME, 0, 0, 0, 0},
41 {".", 0, 0, 0, 0},
42 {"..", 0, 0, 0, 0},
43 {"/", 0, 0, 0, 0},
44 {"missing", -1, ENOENT, -1, ENOENT},
45 {LINK_NAME1, -1, ELOOP, -1, ELOOP},
46 };
47
setup(void)48 static void setup(void)
49 {
50 char *cwd;
51 int fd;
52 struct stat statbuf;
53
54 umask(0);
55
56 SAFE_MOUNT(tst_device->dev, MNTPOINT, tst_device->fs_type, 0, NULL);
57
58 cwd = SAFE_GETCWD(NULL, 0);
59 workdir = SAFE_MALLOC(strlen(cwd) + strlen(MNTPOINT) + 2);
60 sprintf(workdir, "%s/%s", cwd, MNTPOINT);
61 free(cwd);
62 SAFE_CHDIR(workdir);
63
64 SAFE_MKDIR(DIR_NAME, 0755);
65 SAFE_MKDIR(BLOCKED_NAME, 0644);
66
67 /* FAT and NTFS override file and directory permissions */
68 SAFE_STAT(BLOCKED_NAME, &statbuf);
69 skip_blocked = statbuf.st_mode & 0111;
70 skip_symlinks = 0;
71 TEST(symlink(LINK_NAME1, LINK_NAME2));
72
73 if (!TST_RET)
74 SAFE_SYMLINK(LINK_NAME2, LINK_NAME1);
75 else if (TST_RET == -1 && (TST_ERR == EPERM || TST_ERR == ENOSYS))
76 skip_symlinks = 1;
77 else
78 tst_brk(TBROK | TTERRNO, "Cannot create symlinks");
79
80 fd = SAFE_CREAT(FILE_NAME, 0644);
81 SAFE_CLOSE(fd);
82
83 if (!ltpuser)
84 ltpuser = SAFE_GETPWNAM(TESTUSER);
85 }
86
check_result(const char * user,const char * name,int retval,int experr)87 static void check_result(const char *user, const char *name, int retval,
88 int experr)
89 {
90 if (TST_RET != retval) {
91 tst_res(TFAIL | TTERRNO,
92 "%s: chdir(\"%s\") returned unexpected value %ld",
93 user, name, TST_RET);
94 return;
95 }
96
97 if (TST_RET != 0 && TST_ERR != experr) {
98 tst_res(TFAIL | TTERRNO,
99 "%s: chdir(\"%s\") returned unexpected error", user,
100 name);
101 return;
102 }
103
104 tst_res(TPASS | TTERRNO, "%s: chdir(\"%s\") returned correct value",
105 user, name);
106 }
107
run(unsigned int n)108 static void run(unsigned int n)
109 {
110 struct test_case *tc = testcase_list + n;
111
112 tst_res(TINFO, "Testing '%s'", tc->name);
113
114 if (tc->root_err == ELOOP && skip_symlinks) {
115 tst_res(TCONF, "Skipping symlink loop test, not supported");
116 return;
117 }
118
119 /* Reset current directory to mountpoint */
120 SAFE_CHDIR(workdir);
121
122 TEST(chdir(tc->name));
123 check_result("root", tc->name, tc->root_ret, tc->root_err);
124
125 if (tc->nobody_err == EACCES && skip_blocked) {
126 tst_res(TCONF, "Skipping unprivileged permission test, "
127 "FS mangles dir mode");
128 return;
129 }
130
131 SAFE_CHDIR(workdir);
132 SAFE_SETEUID(ltpuser->pw_uid);
133 TEST(chdir(tc->name));
134 SAFE_SETEUID(0);
135 check_result(TESTUSER, tc->name, tc->nobody_ret, tc->nobody_err);
136 }
137
cleanup(void)138 static void cleanup(void)
139 {
140 SAFE_CHDIR("..");
141 tst_umount(workdir);
142 free(workdir);
143 }
144
145 static struct tst_test test = {
146 .needs_root = 1,
147 .format_device = 1,
148 .mntpoint = MNTPOINT,
149 .all_filesystems = 1,
150 .test = run,
151 .tcnt = ARRAY_SIZE(testcase_list),
152 .setup = setup,
153 .cleanup = cleanup
154 };
155