1 // SPDX-License-Identifier: GPL-2.0
2 #define _GNU_SOURCE
3 #include <test_progs.h>
4 #include <sys/stat.h>
5 #include <linux/sched.h>
6 #include <sys/syscall.h>
7 
8 #define MAX_PATH_LEN		128
9 #define MAX_FILES		7
10 
11 #include "test_d_path.skel.h"
12 
13 static int duration;
14 
15 static struct {
16 	__u32 cnt;
17 	char paths[MAX_FILES][MAX_PATH_LEN];
18 } src;
19 
20 static int set_pathname(int fd, pid_t pid)
21 {
22 	char buf[MAX_PATH_LEN];
23 
24 	snprintf(buf, MAX_PATH_LEN, "/proc/%d/fd/%d", pid, fd);
25 	return readlink(buf, src.paths[src.cnt++], MAX_PATH_LEN);
26 }
27 
28 static int trigger_fstat_events(pid_t pid)
29 {
30 	int sockfd = -1, procfd = -1, devfd = -1;
31 	int localfd = -1, indicatorfd = -1;
32 	int pipefd[2] = { -1, -1 };
33 	struct stat fileStat;
34 	int ret = -1;
35 
36 	/* unmountable pseudo-filesystems */
37 	if (CHECK(pipe(pipefd) < 0, "trigger", "pipe failed\n"))
38 		return ret;
39 	/* unmountable pseudo-filesystems */
40 	sockfd = socket(AF_INET, SOCK_STREAM, 0);
41 	if (CHECK(sockfd < 0, "trigger", "socket failed\n"))
42 		goto out_close;
43 	/* mountable pseudo-filesystems */
44 	procfd = open("/proc/self/comm", O_RDONLY);
45 	if (CHECK(procfd < 0, "trigger", "open /proc/self/comm failed\n"))
46 		goto out_close;
47 	devfd = open("/dev/urandom", O_RDONLY);
48 	if (CHECK(devfd < 0, "trigger", "open /dev/urandom failed\n"))
49 		goto out_close;
50 	localfd = open("/tmp/d_path_loadgen.txt", O_CREAT | O_RDONLY, 0644);
51 	if (CHECK(localfd < 0, "trigger", "open /tmp/d_path_loadgen.txt failed\n"))
52 		goto out_close;
53 	/* bpf_d_path will return path with (deleted) */
54 	remove("/tmp/d_path_loadgen.txt");
55 	indicatorfd = open("/tmp/", O_PATH);
56 	if (CHECK(indicatorfd < 0, "trigger", "open /tmp/ failed\n"))
57 		goto out_close;
58 
59 	ret = set_pathname(pipefd[0], pid);
60 	if (CHECK(ret < 0, "trigger", "set_pathname failed for pipe[0]\n"))
61 		goto out_close;
62 	ret = set_pathname(pipefd[1], pid);
63 	if (CHECK(ret < 0, "trigger", "set_pathname failed for pipe[1]\n"))
64 		goto out_close;
65 	ret = set_pathname(sockfd, pid);
66 	if (CHECK(ret < 0, "trigger", "set_pathname failed for socket\n"))
67 		goto out_close;
68 	ret = set_pathname(procfd, pid);
69 	if (CHECK(ret < 0, "trigger", "set_pathname failed for proc\n"))
70 		goto out_close;
71 	ret = set_pathname(devfd, pid);
72 	if (CHECK(ret < 0, "trigger", "set_pathname failed for dev\n"))
73 		goto out_close;
74 	ret = set_pathname(localfd, pid);
75 	if (CHECK(ret < 0, "trigger", "set_pathname failed for file\n"))
76 		goto out_close;
77 	ret = set_pathname(indicatorfd, pid);
78 	if (CHECK(ret < 0, "trigger", "set_pathname failed for dir\n"))
79 		goto out_close;
80 
81 	/* triggers vfs_getattr */
82 	fstat(pipefd[0], &fileStat);
83 	fstat(pipefd[1], &fileStat);
84 	fstat(sockfd, &fileStat);
85 	fstat(procfd, &fileStat);
86 	fstat(devfd, &fileStat);
87 	fstat(localfd, &fileStat);
88 	fstat(indicatorfd, &fileStat);
89 
90 out_close:
91 	/* triggers filp_close */
92 	close(pipefd[0]);
93 	close(pipefd[1]);
94 	close(sockfd);
95 	close(procfd);
96 	close(devfd);
97 	close(localfd);
98 	close(indicatorfd);
99 	return ret;
100 }
101 
102 void test_d_path(void)
103 {
104 	struct test_d_path__bss *bss;
105 	struct test_d_path *skel;
106 	int err;
107 
108 	skel = test_d_path__open_and_load();
109 	if (CHECK(!skel, "setup", "d_path skeleton failed\n"))
110 		goto cleanup;
111 
112 	err = test_d_path__attach(skel);
113 	if (CHECK(err, "setup", "attach failed: %d\n", err))
114 		goto cleanup;
115 
116 	bss = skel->bss;
117 	bss->my_pid = getpid();
118 
119 	err = trigger_fstat_events(bss->my_pid);
120 	if (err < 0)
121 		goto cleanup;
122 
123 	if (CHECK(!bss->called_stat,
124 		  "stat",
125 		  "trampoline for security_inode_getattr was not called\n"))
126 		goto cleanup;
127 
128 	if (CHECK(!bss->called_close,
129 		  "close",
130 		  "trampoline for filp_close was not called\n"))
131 		goto cleanup;
132 
133 	for (int i = 0; i < MAX_FILES; i++) {
134 		CHECK(strncmp(src.paths[i], bss->paths_stat[i], MAX_PATH_LEN),
135 		      "check",
136 		      "failed to get stat path[%d]: %s vs %s\n",
137 		      i, src.paths[i], bss->paths_stat[i]);
138 		CHECK(strncmp(src.paths[i], bss->paths_close[i], MAX_PATH_LEN),
139 		      "check",
140 		      "failed to get close path[%d]: %s vs %s\n",
141 		      i, src.paths[i], bss->paths_close[i]);
142 		/* The d_path helper returns size plus NUL char, hence + 1 */
143 		CHECK(bss->rets_stat[i] != strlen(bss->paths_stat[i]) + 1,
144 		      "check",
145 		      "failed to match stat return [%d]: %d vs %zd [%s]\n",
146 		      i, bss->rets_stat[i], strlen(bss->paths_stat[i]) + 1,
147 		      bss->paths_stat[i]);
148 		CHECK(bss->rets_close[i] != strlen(bss->paths_stat[i]) + 1,
149 		      "check",
150 		      "failed to match stat return [%d]: %d vs %zd [%s]\n",
151 		      i, bss->rets_close[i], strlen(bss->paths_close[i]) + 1,
152 		      bss->paths_stat[i]);
153 	}
154 
155 cleanup:
156 	test_d_path__destroy(skel);
157 }
158