1 /*
2  * Copyright (c) 2019 Alexey Dobriyan <adobriyan@gmail.com>
3  *
4  * Permission to use, copy, modify, and distribute this software for any
5  * purpose with or without fee is hereby granted, provided that the above
6  * copyright notice and this permission notice appear in all copies.
7  *
8  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
9  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
10  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
11  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
12  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
13  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
14  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
15  */
16 /* Test that pointing #! script interpreter to self doesn't recurse. */
17 #include <errno.h>
18 #include <sched.h>
19 #include <stdio.h>
20 #include <string.h>
21 #include <sys/types.h>
22 #include <sys/stat.h>
23 #include <fcntl.h>
24 #include <sys/mount.h>
25 #include <unistd.h>
26 
main(void)27 int main(void)
28 {
29 	if (unshare(CLONE_NEWNS) == -1) {
30 		if (errno == ENOSYS || errno == EPERM) {
31 			fprintf(stderr, "error: unshare, errno %d\n", errno);
32 			return 4;
33 		}
34 		fprintf(stderr, "error: unshare, errno %d\n", errno);
35 		return 1;
36 	}
37 	if (mount(NULL, "/", NULL, MS_PRIVATE|MS_REC, NULL) == -1) {
38 		fprintf(stderr, "error: mount '/', errno %d\n", errno);
39 		return 1;
40 	}
41 	/* Require "exec" filesystem. */
42 	if (mount(NULL, "/tmp", "ramfs", 0, NULL) == -1) {
43 		fprintf(stderr, "error: mount ramfs, errno %d\n", errno);
44 		return 1;
45 	}
46 
47 #define FILENAME "/tmp/1"
48 
49 	int fd = creat(FILENAME, 0700);
50 	if (fd == -1) {
51 		fprintf(stderr, "error: creat, errno %d\n", errno);
52 		return 1;
53 	}
54 #define S "#!" FILENAME "\n"
55 	if (write(fd, S, strlen(S)) != strlen(S)) {
56 		fprintf(stderr, "error: write, errno %d\n", errno);
57 		return 1;
58 	}
59 	close(fd);
60 
61 	int rv = execve(FILENAME, NULL, NULL);
62 	if (rv == -1 && errno == ELOOP) {
63 		return 0;
64 	}
65 	fprintf(stderr, "error: execve, rv %d, errno %d\n", rv, errno);
66 	return 1;
67 }
68