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1// SPDX-License-Identifier: GPL-2.0
2
3/*
4 * Copyright (C) 2020 Google LLC.
5 */
6
7#include <asm-generic/errno-base.h>
8#include <sys/stat.h>
9#include <test_progs.h>
10#include <linux/limits.h>
11
12#include "local_storage.skel.h"
13#include "network_helpers.h"
14#include "task_local_storage_helpers.h"
15
16#define TEST_STORAGE_VALUE 0xbeefdead
17
18struct storage {
19 void *inode;
20 unsigned int value;
21};
22
23/* Fork and exec the provided rm binary and return the exit code of the
24 * forked process and its pid.
25 */
26static int run_self_unlink(struct local_storage *skel, const char *rm_path)
27{
28 int child_pid, child_status, ret;
29 int null_fd;
30
31 child_pid = fork();
32 if (child_pid == 0) {
33 null_fd = open("/dev/null", O_WRONLY);
34 dup2(null_fd, STDOUT_FILENO);
35 dup2(null_fd, STDERR_FILENO);
36 close(null_fd);
37
38 skel->bss->monitored_pid = getpid();
39 /* Use the copied /usr/bin/rm to delete itself
40 * /tmp/copy_of_rm /tmp/copy_of_rm.
41 */
42 ret = execlp(rm_path, rm_path, rm_path, NULL);
43 if (ret)
44 exit(errno);
45 } else if (child_pid > 0) {
46 waitpid(child_pid, &child_status, 0);
47 ASSERT_EQ(skel->data->task_storage_result, 0, "task_storage_result");
48 return WEXITSTATUS(child_status);
49 }
50
51 return -EINVAL;
52}
53
54static bool check_syscall_operations(int map_fd, int obj_fd)
55{
56 struct storage val = { .value = TEST_STORAGE_VALUE },
57 lookup_val = { .value = 0 };
58 int err;
59
60 /* Looking up an existing element should fail initially */
61 err = bpf_map_lookup_elem_flags(map_fd, &obj_fd, &lookup_val, 0);
62 if (!ASSERT_EQ(err, -ENOENT, "bpf_map_lookup_elem"))
63 return false;
64
65 /* Create a new element */
66 err = bpf_map_update_elem(map_fd, &obj_fd, &val, BPF_NOEXIST);
67 if (!ASSERT_OK(err, "bpf_map_update_elem"))
68 return false;
69
70 /* Lookup the newly created element */
71 err = bpf_map_lookup_elem_flags(map_fd, &obj_fd, &lookup_val, 0);
72 if (!ASSERT_OK(err, "bpf_map_lookup_elem"))
73 return false;
74
75 /* Check the value of the newly created element */
76 if (!ASSERT_EQ(lookup_val.value, val.value, "bpf_map_lookup_elem"))
77 return false;
78
79 err = bpf_map_delete_elem(map_fd, &obj_fd);
80 if (!ASSERT_OK(err, "bpf_map_delete_elem()"))
81 return false;
82
83 /* The lookup should fail, now that the element has been deleted */
84 err = bpf_map_lookup_elem_flags(map_fd, &obj_fd, &lookup_val, 0);
85 if (!ASSERT_EQ(err, -ENOENT, "bpf_map_lookup_elem"))
86 return false;
87
88 return true;
89}
90
91void test_test_local_storage(void)
92{
93 char tmp_dir_path[] = "/tmp/local_storageXXXXXX";
94 int err, serv_sk = -1, task_fd = -1, rm_fd = -1;
95 struct local_storage *skel = NULL;
96 char tmp_exec_path[64];
97 char cmd[256];
98
99 skel = local_storage__open_and_load();
100 if (!ASSERT_OK_PTR(skel, "skel_load"))
101 goto close_prog;
102
103 err = local_storage__attach(skel);
104 if (!ASSERT_OK(err, "attach"))
105 goto close_prog;
106
107 task_fd = sys_pidfd_open(getpid(), 0);
108 if (!ASSERT_GE(task_fd, 0, "pidfd_open"))
109 goto close_prog;
110
111 if (!check_syscall_operations(bpf_map__fd(skel->maps.task_storage_map),
112 task_fd))
113 goto close_prog;
114
115 if (!ASSERT_OK_PTR(mkdtemp(tmp_dir_path), "mkdtemp"))
116 goto close_prog;
117
118 snprintf(tmp_exec_path, sizeof(tmp_exec_path), "%s/copy_of_rm",
119 tmp_dir_path);
120 snprintf(cmd, sizeof(cmd), "cp /bin/rm %s", tmp_exec_path);
121 if (!ASSERT_OK(system(cmd), "system(cp)"))
122 goto close_prog_rmdir;
123
124 rm_fd = open(tmp_exec_path, O_RDONLY);
125 if (!ASSERT_GE(rm_fd, 0, "open(tmp_exec_path)"))
126 goto close_prog_rmdir;
127
128 if (!check_syscall_operations(bpf_map__fd(skel->maps.inode_storage_map),
129 rm_fd))
130 goto close_prog_rmdir;
131
132 /* Sets skel->bss->monitored_pid to the pid of the forked child
133 * forks a child process that executes tmp_exec_path and tries to
134 * unlink its executable. This operation should be denied by the loaded
135 * LSM program.
136 */
137 err = run_self_unlink(skel, tmp_exec_path);
138 if (!ASSERT_EQ(err, EPERM, "run_self_unlink"))
139 goto close_prog_rmdir;
140
141 /* Set the process being monitored to be the current process */
142 skel->bss->monitored_pid = getpid();
143
144 /* Move copy_of_rm to a new location so that it triggers the
145 * inode_rename LSM hook with a new_dentry that has a NULL inode ptr.
146 */
147 snprintf(cmd, sizeof(cmd), "mv %s/copy_of_rm %s/check_null_ptr",
148 tmp_dir_path, tmp_dir_path);
149 if (!ASSERT_OK(system(cmd), "system(mv)"))
150 goto close_prog_rmdir;
151
152 ASSERT_EQ(skel->data->inode_storage_result, 0, "inode_storage_result");
153
154 serv_sk = start_server(AF_INET6, SOCK_STREAM, NULL, 0, 0);
155 if (!ASSERT_GE(serv_sk, 0, "start_server"))
156 goto close_prog_rmdir;
157
158 ASSERT_EQ(skel->data->sk_storage_result, 0, "sk_storage_result");
159
160 if (!check_syscall_operations(bpf_map__fd(skel->maps.sk_storage_map),
161 serv_sk))
162 goto close_prog_rmdir;
163
164close_prog_rmdir:
165 snprintf(cmd, sizeof(cmd), "rm -rf %s", tmp_dir_path);
166 system(cmd);
167close_prog:
168 close(serv_sk);
169 close(rm_fd);
170 close(task_fd);
171 local_storage__destroy(skel);
172}
1// SPDX-License-Identifier: GPL-2.0
2
3/*
4 * Copyright (C) 2020 Google LLC.
5 */
6
7#include <asm-generic/errno-base.h>
8#include <sys/stat.h>
9#include <test_progs.h>
10#include <linux/limits.h>
11
12#include "local_storage.skel.h"
13#include "network_helpers.h"
14#include "task_local_storage_helpers.h"
15
16static unsigned int duration;
17
18#define TEST_STORAGE_VALUE 0xbeefdead
19
20struct storage {
21 void *inode;
22 unsigned int value;
23};
24
25/* Fork and exec the provided rm binary and return the exit code of the
26 * forked process and its pid.
27 */
28static int run_self_unlink(int *monitored_pid, const char *rm_path)
29{
30 int child_pid, child_status, ret;
31 int null_fd;
32
33 child_pid = fork();
34 if (child_pid == 0) {
35 null_fd = open("/dev/null", O_WRONLY);
36 dup2(null_fd, STDOUT_FILENO);
37 dup2(null_fd, STDERR_FILENO);
38 close(null_fd);
39
40 *monitored_pid = getpid();
41 /* Use the copied /usr/bin/rm to delete itself
42 * /tmp/copy_of_rm /tmp/copy_of_rm.
43 */
44 ret = execlp(rm_path, rm_path, rm_path, NULL);
45 if (ret)
46 exit(errno);
47 } else if (child_pid > 0) {
48 waitpid(child_pid, &child_status, 0);
49 return WEXITSTATUS(child_status);
50 }
51
52 return -EINVAL;
53}
54
55static bool check_syscall_operations(int map_fd, int obj_fd)
56{
57 struct storage val = { .value = TEST_STORAGE_VALUE },
58 lookup_val = { .value = 0 };
59 int err;
60
61 /* Looking up an existing element should fail initially */
62 err = bpf_map_lookup_elem_flags(map_fd, &obj_fd, &lookup_val, 0);
63 if (CHECK(!err || errno != ENOENT, "bpf_map_lookup_elem",
64 "err:%d errno:%d\n", err, errno))
65 return false;
66
67 /* Create a new element */
68 err = bpf_map_update_elem(map_fd, &obj_fd, &val, BPF_NOEXIST);
69 if (CHECK(err < 0, "bpf_map_update_elem", "err:%d errno:%d\n", err,
70 errno))
71 return false;
72
73 /* Lookup the newly created element */
74 err = bpf_map_lookup_elem_flags(map_fd, &obj_fd, &lookup_val, 0);
75 if (CHECK(err < 0, "bpf_map_lookup_elem", "err:%d errno:%d", err,
76 errno))
77 return false;
78
79 /* Check the value of the newly created element */
80 if (CHECK(lookup_val.value != val.value, "bpf_map_lookup_elem",
81 "value got = %x errno:%d", lookup_val.value, val.value))
82 return false;
83
84 err = bpf_map_delete_elem(map_fd, &obj_fd);
85 if (CHECK(err, "bpf_map_delete_elem()", "err:%d errno:%d\n", err,
86 errno))
87 return false;
88
89 /* The lookup should fail, now that the element has been deleted */
90 err = bpf_map_lookup_elem_flags(map_fd, &obj_fd, &lookup_val, 0);
91 if (CHECK(!err || errno != ENOENT, "bpf_map_lookup_elem",
92 "err:%d errno:%d\n", err, errno))
93 return false;
94
95 return true;
96}
97
98void test_test_local_storage(void)
99{
100 char tmp_dir_path[] = "/tmp/local_storageXXXXXX";
101 int err, serv_sk = -1, task_fd = -1, rm_fd = -1;
102 struct local_storage *skel = NULL;
103 char tmp_exec_path[64];
104 char cmd[256];
105
106 skel = local_storage__open_and_load();
107 if (CHECK(!skel, "skel_load", "lsm skeleton failed\n"))
108 goto close_prog;
109
110 err = local_storage__attach(skel);
111 if (CHECK(err, "attach", "lsm attach failed: %d\n", err))
112 goto close_prog;
113
114 task_fd = sys_pidfd_open(getpid(), 0);
115 if (CHECK(task_fd < 0, "pidfd_open",
116 "failed to get pidfd err:%d, errno:%d", task_fd, errno))
117 goto close_prog;
118
119 if (!check_syscall_operations(bpf_map__fd(skel->maps.task_storage_map),
120 task_fd))
121 goto close_prog;
122
123 if (CHECK(!mkdtemp(tmp_dir_path), "mkdtemp",
124 "unable to create tmpdir: %d\n", errno))
125 goto close_prog;
126
127 snprintf(tmp_exec_path, sizeof(tmp_exec_path), "%s/copy_of_rm",
128 tmp_dir_path);
129 snprintf(cmd, sizeof(cmd), "cp /bin/rm %s", tmp_exec_path);
130 if (CHECK_FAIL(system(cmd)))
131 goto close_prog_rmdir;
132
133 rm_fd = open(tmp_exec_path, O_RDONLY);
134 if (CHECK(rm_fd < 0, "open", "failed to open %s err:%d, errno:%d",
135 tmp_exec_path, rm_fd, errno))
136 goto close_prog_rmdir;
137
138 if (!check_syscall_operations(bpf_map__fd(skel->maps.inode_storage_map),
139 rm_fd))
140 goto close_prog_rmdir;
141
142 /* Sets skel->bss->monitored_pid to the pid of the forked child
143 * forks a child process that executes tmp_exec_path and tries to
144 * unlink its executable. This operation should be denied by the loaded
145 * LSM program.
146 */
147 err = run_self_unlink(&skel->bss->monitored_pid, tmp_exec_path);
148 if (CHECK(err != EPERM, "run_self_unlink", "err %d want EPERM\n", err))
149 goto close_prog_rmdir;
150
151 /* Set the process being monitored to be the current process */
152 skel->bss->monitored_pid = getpid();
153
154 /* Move copy_of_rm to a new location so that it triggers the
155 * inode_rename LSM hook with a new_dentry that has a NULL inode ptr.
156 */
157 snprintf(cmd, sizeof(cmd), "mv %s/copy_of_rm %s/check_null_ptr",
158 tmp_dir_path, tmp_dir_path);
159 if (CHECK_FAIL(system(cmd)))
160 goto close_prog_rmdir;
161
162 CHECK(skel->data->inode_storage_result != 0, "inode_storage_result",
163 "inode_local_storage not set\n");
164
165 serv_sk = start_server(AF_INET6, SOCK_STREAM, NULL, 0, 0);
166 if (CHECK(serv_sk < 0, "start_server", "failed to start server\n"))
167 goto close_prog_rmdir;
168
169 CHECK(skel->data->sk_storage_result != 0, "sk_storage_result",
170 "sk_local_storage not set\n");
171
172 if (!check_syscall_operations(bpf_map__fd(skel->maps.sk_storage_map),
173 serv_sk))
174 goto close_prog_rmdir;
175
176close_prog_rmdir:
177 snprintf(cmd, sizeof(cmd), "rm -rf %s", tmp_dir_path);
178 system(cmd);
179close_prog:
180 close(serv_sk);
181 close(rm_fd);
182 close(task_fd);
183 local_storage__destroy(skel);
184}