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 #include "safe_macros.h"
43
44 char *TCID = "readlink04";
45 int TST_TOTAL = 1;
46
47 static char *TESTFILE = "./testfile";
48 static char *SYMFILE = "slink_file";
49
50 #define MAX_SIZE 256
51
52 static int exp_val;
53 static char buffer[MAX_SIZE];
54
55 static void setup(void);
56 static void cleanup(void);
57
main(int ac,char ** av)58 int main(int ac, char **av)
59 {
60 int lc;
61
62 tst_parse_opts(ac, av, NULL, NULL);
63
64 setup();
65
66 for (lc = 0; TEST_LOOPING(lc); lc++) {
67
68 tst_count = 0;
69
70 /*
71 * Call readlink(2) to read the contents of
72 * symlink into a buffer.
73 */
74 TEST(readlink(SYMFILE, buffer, sizeof(buffer)));
75
76 if (TEST_RETURN == -1) {
77 tst_resm(TFAIL | TTERRNO, "readlink() on %s failed",
78 SYMFILE);
79 continue;
80 }
81
82 if (TEST_RETURN == exp_val) {
83 /* Check for the contents of buffer */
84 if (memcmp(buffer, TESTFILE, exp_val) != 0) {
85 tst_brkm(TFAIL, cleanup, "TESTFILE %s "
86 "and buffer contents %s "
87 "differ", TESTFILE, buffer);
88 } else {
89 tst_resm(TPASS, "readlink() "
90 "functionality on '%s' is "
91 "correct", SYMFILE);
92 }
93 } else {
94 tst_resm(TFAIL, "readlink() return value %ld "
95 "doesn't match, Expected %d",
96 TEST_RETURN, exp_val);
97 }
98 }
99
100 cleanup();
101 tst_exit();
102 }
103
104 #define FILE_MODE S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH
105
setup(void)106 static void setup(void)
107 {
108 int fd;
109 char *tmp_dir = NULL;
110 struct passwd *pwent;
111
112 tst_require_root();
113
114 TEST_PAUSE;
115
116 tst_tmpdir();
117
118 /* get the name of the temporary directory */
119 if ((tmp_dir = getcwd(tmp_dir, 0)) == NULL)
120 tst_brkm(TBROK, NULL, "getcwd failed");
121
122 if ((pwent = getpwnam("bin")) == NULL)
123 tst_brkm(TBROK, cleanup, "getpwname() failed");
124
125 /* make the tmp directory belong to bin */
126 SAFE_CHOWN(cleanup, tmp_dir, pwent->pw_uid, pwent->pw_gid);
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 SAFE_SYMLINK(cleanup, TESTFILE, SYMFILE);
139
140 /* set up the expected return value from the readlink() call */
141 exp_val = strlen(TESTFILE);
142
143 /* fill the buffer with a known value */
144 memset(buffer, 0, MAX_SIZE);
145
146 /* finally, change the id of the parent process to "nobody" */
147 if ((pwent = getpwnam("nobody")) == NULL)
148 tst_brkm(TBROK, cleanup, "getpwname() failed for nobody");
149
150 SAFE_SETEUID(cleanup, pwent->pw_uid);
151 }
152
cleanup(void)153 static void cleanup(void)
154 {
155 SAFE_SETEUID(NULL, 0);
156
157 tst_rmdir();
158 }
159