1 /*
2 * Copyright (c) International Business Machines Corp., 2001
3 * Copyright (c) 2013 Cyril Hrubis <chrubis@suse.cz>
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 2 of the License, or
8 * (at your option) any later version.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
13 * the GNU General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
18 */
19
20 /*
21 * Test Name : readlink04
22 *
23 * Test Description :
24 * Verify that, readlink call will succeed to read the contents of the
25 * symbolic link if invoked by non-root user who is not the owner of the
26 * symbolic link.
27 *
28 * Expected Result:
29 * readlink() should return the contents of symbolic link path in the
30 * specified buffer on success.
31 */
32
33 #include <stdlib.h>
34 #include <pwd.h>
35 #include <sys/types.h>
36 #include <sys/stat.h>
37 #include <fcntl.h>
38 #include <sys/wait.h>
39 #include <errno.h>
40 #include <string.h>
41 #include "test.h"
42
43 char *TCID = "readlink04";
44 int TST_TOTAL = 1;
45
46 static char *TESTFILE = "./testfile";
47 static char *SYMFILE = "slink_file";
48
49 #define MAX_SIZE 256
50
51 static int exp_val;
52 static char buffer[MAX_SIZE];
53
54 static void setup(void);
55 static void cleanup(void);
56
main(int ac,char ** av)57 int main(int ac, char **av)
58 {
59 int lc;
60
61 tst_parse_opts(ac, av, NULL, NULL);
62
63 setup();
64
65 for (lc = 0; TEST_LOOPING(lc); lc++) {
66
67 tst_count = 0;
68
69 /*
70 * Call readlink(2) to read the contents of
71 * symlink into a buffer.
72 */
73 TEST(readlink(SYMFILE, buffer, sizeof(buffer)));
74
75 if (TEST_RETURN == -1) {
76 tst_resm(TFAIL | TTERRNO, "readlink() on %s failed",
77 SYMFILE);
78 continue;
79 }
80
81 if (TEST_RETURN == exp_val) {
82 /* Check for the contents of buffer */
83 if (memcmp(buffer, TESTFILE, exp_val) != 0) {
84 tst_brkm(TFAIL, cleanup, "TESTFILE %s "
85 "and buffer contents %s "
86 "differ", TESTFILE, buffer);
87 } else {
88 tst_resm(TPASS, "readlink() "
89 "functionality on '%s' is "
90 "correct", SYMFILE);
91 }
92 } else {
93 tst_resm(TFAIL, "readlink() return value %ld "
94 "doesn't match, Expected %d",
95 TEST_RETURN, exp_val);
96 }
97 }
98
99 cleanup();
100 tst_exit();
101 }
102
103 #define FILE_MODE S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH
104
setup(void)105 static void setup(void)
106 {
107 int fd;
108 char *tmp_dir = NULL;
109 struct passwd *pwent;
110
111 tst_require_root();
112
113 TEST_PAUSE;
114
115 tst_tmpdir();
116
117 /* get the name of the temporary directory */
118 if ((tmp_dir = getcwd(tmp_dir, 0)) == NULL)
119 tst_brkm(TBROK, NULL, "getcwd failed");
120
121 if ((pwent = getpwnam("bin")) == NULL)
122 tst_brkm(TBROK, cleanup, "getpwname() failed");
123
124 /* make the tmp directory belong to bin */
125 if (chown(tmp_dir, pwent->pw_uid, pwent->pw_gid) == -1)
126 tst_brkm(TBROK, cleanup, "chown() failed");
127
128 if (chmod(tmp_dir, 0711) != 0)
129 tst_brkm(TBROK|TERRNO, cleanup, "chmod(%s) failed", tmp_dir);
130
131 /* create test file and symlink */
132 if ((fd = open(TESTFILE, O_RDWR | O_CREAT, FILE_MODE)) == -1)
133 tst_brkm(TBROK|TERRNO, cleanup, "open(%s) failed", TESTFILE);
134
135 if (close(fd))
136 tst_brkm(TBROK|TERRNO, cleanup, "close(%s) failed", TESTFILE);
137
138 if (symlink(TESTFILE, SYMFILE) < 0) {
139 tst_brkm(TBROK|TERRNO, cleanup, "symlink(%s, %s) failed",
140 TESTFILE, SYMFILE);
141 }
142
143 /* set up the expected return value from the readlink() call */
144 exp_val = strlen(TESTFILE);
145
146 /* fill the buffer with a known value */
147 memset(buffer, 0, MAX_SIZE);
148
149 /* finally, change the id of the parent process to "nobody" */
150 if ((pwent = getpwnam("nobody")) == NULL)
151 tst_brkm(TBROK, cleanup, "getpwname() failed for nobody");
152
153 if (seteuid(pwent->pw_uid) == -1)
154 tst_brkm(TBROK, cleanup, "seteuid() failed for nobody");
155 }
156
cleanup(void)157 static void cleanup(void)
158 {
159 if (seteuid(0) == -1)
160 tst_brkm(TBROK, NULL, "failed to set process id to root");
161
162 tst_rmdir();
163 }
164