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 char *file_name;
35 static char *blocked_name;
36 static char *dir_name;
37 static char *cwd_name;
38 static char *parent_name;
39 static char *root_name;
40 static char *missing_name;
41 static char *link_name;
42
43 static struct test_case {
44 char **name;
45 int root_ret, root_err, nobody_ret, nobody_err;
46 } testcase_list[] = {
47 {&file_name, -1, ENOTDIR, -1, ENOTDIR},
48 {&blocked_name, 0, 0, -1, EACCES},
49 {&dir_name, 0, 0, 0, 0},
50 {&cwd_name, 0, 0, 0, 0},
51 {&parent_name, 0, 0, 0, 0},
52 {&root_name, 0, 0, 0, 0},
53 {&missing_name, -1, ENOENT, -1, ENOENT},
54 {&link_name, -1, ELOOP, -1, ELOOP},
55 };
56
setup(void)57 static void setup(void)
58 {
59 char *cwd;
60 int fd;
61 struct stat statbuf;
62
63 umask(0);
64
65 cwd = SAFE_GETCWD(NULL, 0);
66 workdir = SAFE_MALLOC(strlen(cwd) + strlen(MNTPOINT) + 2);
67 sprintf(workdir, "%s/%s", cwd, MNTPOINT);
68 free(cwd);
69 SAFE_CHDIR(workdir);
70
71 SAFE_MKDIR(DIR_NAME, 0755);
72 SAFE_MKDIR(BLOCKED_NAME, 0644);
73
74 /* FAT and NTFS override file and directory permissions */
75 SAFE_STAT(BLOCKED_NAME, &statbuf);
76 skip_blocked = statbuf.st_mode & 0111;
77 skip_symlinks = 0;
78 TEST(symlink(LINK_NAME1, LINK_NAME2));
79
80 if (!TST_RET)
81 SAFE_SYMLINK(LINK_NAME2, LINK_NAME1);
82 else if (TST_RET == -1 && (TST_ERR == EPERM || TST_ERR == ENOSYS))
83 skip_symlinks = 1;
84 else
85 tst_brk(TBROK | TTERRNO, "Cannot create symlinks");
86
87 fd = SAFE_CREAT(FILE_NAME, 0644);
88 SAFE_CLOSE(fd);
89
90 if (!ltpuser)
91 ltpuser = SAFE_GETPWNAM(TESTUSER);
92 }
93
check_result(const char * user,const char * name,int retval,int experr)94 static void check_result(const char *user, const char *name, int retval,
95 int experr)
96 {
97 if (TST_RET != retval) {
98 tst_res(TFAIL | TTERRNO,
99 "%s: chdir(\"%s\") returned unexpected value %ld",
100 user, name, TST_RET);
101 return;
102 }
103
104 if (TST_RET != 0 && TST_ERR != experr) {
105 tst_res(TFAIL | TTERRNO,
106 "%s: chdir(\"%s\") returned unexpected error", user,
107 name);
108 return;
109 }
110
111 tst_res(TPASS | TTERRNO, "%s: chdir(\"%s\") returned correct value",
112 user, name);
113 }
114
run(unsigned int n)115 static void run(unsigned int n)
116 {
117 struct test_case *tc = testcase_list + n;
118
119 tst_res(TINFO, "Testing '%s'", *tc->name);
120
121 if (tc->root_err == ELOOP && skip_symlinks) {
122 tst_res(TCONF, "Skipping symlink loop test, not supported");
123 return;
124 }
125
126 /* Reset current directory to mountpoint */
127 SAFE_CHDIR(workdir);
128
129 TEST(chdir(*tc->name));
130 check_result("root", *tc->name, tc->root_ret, tc->root_err);
131
132 if (tc->nobody_err == EACCES && skip_blocked) {
133 tst_res(TCONF, "Skipping unprivileged permission test, "
134 "FS mangles dir mode");
135 return;
136 }
137
138 SAFE_CHDIR(workdir);
139 SAFE_SETEUID(ltpuser->pw_uid);
140 TEST(chdir(*tc->name));
141 SAFE_SETEUID(0);
142 check_result(TESTUSER, *tc->name, tc->nobody_ret, tc->nobody_err);
143 }
144
cleanup(void)145 static void cleanup(void)
146 {
147 SAFE_CHDIR("..");
148 free(workdir);
149 }
150
151 static struct tst_test test = {
152 .needs_root = 1,
153 .mount_device = 1,
154 .mntpoint = MNTPOINT,
155 .all_filesystems = 1,
156 .test = run,
157 .tcnt = ARRAY_SIZE(testcase_list),
158 .setup = setup,
159 .cleanup = cleanup,
160 .bufs = (struct tst_buffers []) {
161 {&file_name, .str = FILE_NAME},
162 {&blocked_name, .str = BLOCKED_NAME},
163 {&dir_name, .str = DIR_NAME},
164 {&cwd_name, .str = "."},
165 {&parent_name, .str = ".."},
166 {&root_name, .str = "/"},
167 {&missing_name, .str = "does_not_exist"},
168 {&link_name, .str = LINK_NAME1},
169 {}
170 }
171 };
172