1 /*
2  * Copyright (c) Kerlabs 2008.
3  * Copyright (c) International Business Machines  Corp., 2008
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  * Created by Renaud Lottiaux
20  */
21 
22 /*
23  * Check if setreuid behaves correctly with file permissions.
24  * The test creates a file as ROOT with permissions 0644, does a setreuid
25  * and then tries to open the file with RDWR permissions.
26  * The same test is done in a fork to check if new UIDs are correctly
27  * passed to the son.
28  */
29 
30 #include <errno.h>
31 #include <sys/types.h>
32 #include <sys/stat.h>
33 #include <sys/wait.h>
34 #include <fcntl.h>
35 #include <unistd.h>
36 #include <pwd.h>
37 
38 #include "test.h"
39 #include "safe_macros.h"
40 #include "compat_16.h"
41 
42 TCID_DEFINE(setreuid07);
43 int TST_TOTAL = 1;
44 
45 static char testfile[256] = "";
46 static struct passwd *ltpuser;
47 
48 static int fd = -1;
49 
50 static void setup(void);
51 static void cleanup(void);
52 static void do_master_child(void);
53 
54 int main(int ac, char **av)
55 {
56 	pid_t pid;
57 
58 	tst_parse_opts(ac, av, NULL, NULL);
59 
60 	setup();
61 
62 	pid = FORK_OR_VFORK();
63 	if (pid < 0)
64 		tst_brkm(TBROK, cleanup, "Fork failed");
65 
66 	if (pid == 0)
67 		do_master_child();
68 
69 	tst_record_childstatus(cleanup, pid);
70 
71 	cleanup();
72 	tst_exit();
73 }
74 
75 static void do_master_child(void)
76 {
77 	int lc;
78 	int pid;
79 	int status;
80 
81 	for (lc = 0; TEST_LOOPING(lc); lc++) {
82 		int tst_fd;
83 
84 		tst_count = 0;
85 
86 		if (SETREUID(NULL, 0, ltpuser->pw_uid) == -1) {
87 			perror("setreuid failed");
88 			exit(TFAIL);
89 		}
90 
91 		/* Test 1: Check the process with new uid cannot open the file
92 		 *         with RDWR permissions.
93 		 */
94 		TEST(tst_fd = open(testfile, O_RDWR));
95 
96 		if (TEST_RETURN != -1) {
97 			printf("open succeeded unexpectedly\n");
98 			close(tst_fd);
99 			exit(TFAIL);
100 		}
101 
102 		if (TEST_ERRNO == EACCES) {
103 			printf("open failed with EACCES as expected\n");
104 		} else {
105 			perror("open failed unexpectedly");
106 			exit(TFAIL);
107 		}
108 
109 		/* Test 2: Check a son process cannot open the file
110 		 *         with RDWR permissions.
111 		 */
112 		pid = FORK_OR_VFORK();
113 		if (pid < 0)
114 			tst_brkm(TBROK, cleanup, "Fork failed");
115 
116 		if (pid == 0) {
117 			int tst_fd2;
118 
119 			/* Test to open the file in son process */
120 			TEST(tst_fd2 = open(testfile, O_RDWR));
121 
122 			if (TEST_RETURN != -1) {
123 				printf("call succeeded unexpectedly\n");
124 				close(tst_fd2);
125 				exit(TFAIL);
126 			}
127 
128 			if (TEST_ERRNO == EACCES) {
129 				printf("open failed with EACCES as expected\n");
130 				exit(TPASS);
131 			} else {
132 				printf("open failed unexpectedly\n");
133 				exit(TFAIL);
134 			}
135 		} else {
136 			/* Wait for son completion */
137 			if (waitpid(pid, &status, 0) == -1) {
138 				perror("waitpid failed");
139 				exit(TFAIL);
140 			}
141 			if (!WIFEXITED(status) || (WEXITSTATUS(status) != 0))
142 				exit(WEXITSTATUS(status));
143 		}
144 
145 		/* Test 3: Fallback to initial uid and check we can again open
146 		 *         the file with RDWR permissions.
147 		 */
148 		tst_count++;
149 		if (SETREUID(NULL, 0, 0) == -1) {
150 			perror("setreuid failed");
151 			exit(TFAIL);
152 		}
153 
154 		TEST(tst_fd = open(testfile, O_RDWR));
155 
156 		if (TEST_RETURN == -1) {
157 			perror("open failed unexpectedly");
158 			exit(TFAIL);
159 		} else {
160 			printf("open call succeeded\n");
161 			close(tst_fd);
162 		}
163 	}
164 	exit(TPASS);
165 }
166 
167 static void setup(void)
168 {
169 	tst_require_root();
170 
171 	ltpuser = getpwnam("nobody");
172 	if (ltpuser == NULL)
173 		tst_brkm(TBROK, NULL, "nobody must be a valid user.");
174 
175 	tst_tmpdir();
176 
177 	sprintf(testfile, "setreuid07file%d.tst", getpid());
178 
179 	/* Create test file */
180 	fd = SAFE_OPEN(cleanup, testfile, O_CREAT | O_RDWR, 0644);
181 
182 	tst_sig(FORK, DEF_HANDLER, cleanup);
183 
184 	TEST_PAUSE;
185 }
186 
187 static void cleanup(void)
188 {
189 	close(fd);
190 
191 	tst_rmdir();
192 }
193