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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
15#ifndef __NR_pidfd_open
16#define __NR_pidfd_open 434
17#endif
18
19static inline int sys_pidfd_open(pid_t pid, unsigned int flags)
20{
21 return syscall(__NR_pidfd_open, pid, flags);
22}
23
24static unsigned int duration;
25
26#define TEST_STORAGE_VALUE 0xbeefdead
27
28struct storage {
29 void *inode;
30 unsigned int value;
31 /* Lock ensures that spin locked versions of local stoage operations
32 * also work, most operations in this tests are still single threaded
33 */
34 struct bpf_spin_lock lock;
35};
36
37/* Fork and exec the provided rm binary and return the exit code of the
38 * forked process and its pid.
39 */
40static int run_self_unlink(int *monitored_pid, const char *rm_path)
41{
42 int child_pid, child_status, ret;
43 int null_fd;
44
45 child_pid = fork();
46 if (child_pid == 0) {
47 null_fd = open("/dev/null", O_WRONLY);
48 dup2(null_fd, STDOUT_FILENO);
49 dup2(null_fd, STDERR_FILENO);
50 close(null_fd);
51
52 *monitored_pid = getpid();
53 /* Use the copied /usr/bin/rm to delete itself
54 * /tmp/copy_of_rm /tmp/copy_of_rm.
55 */
56 ret = execlp(rm_path, rm_path, rm_path, NULL);
57 if (ret)
58 exit(errno);
59 } else if (child_pid > 0) {
60 waitpid(child_pid, &child_status, 0);
61 return WEXITSTATUS(child_status);
62 }
63
64 return -EINVAL;
65}
66
67static bool check_syscall_operations(int map_fd, int obj_fd)
68{
69 struct storage val = { .value = TEST_STORAGE_VALUE, .lock = { 0 } },
70 lookup_val = { .value = 0, .lock = { 0 } };
71 int err;
72
73 /* Looking up an existing element should fail initially */
74 err = bpf_map_lookup_elem_flags(map_fd, &obj_fd, &lookup_val,
75 BPF_F_LOCK);
76 if (CHECK(!err || errno != ENOENT, "bpf_map_lookup_elem",
77 "err:%d errno:%d\n", err, errno))
78 return false;
79
80 /* Create a new element */
81 err = bpf_map_update_elem(map_fd, &obj_fd, &val,
82 BPF_NOEXIST | BPF_F_LOCK);
83 if (CHECK(err < 0, "bpf_map_update_elem", "err:%d errno:%d\n", err,
84 errno))
85 return false;
86
87 /* Lookup the newly created element */
88 err = bpf_map_lookup_elem_flags(map_fd, &obj_fd, &lookup_val,
89 BPF_F_LOCK);
90 if (CHECK(err < 0, "bpf_map_lookup_elem", "err:%d errno:%d", err,
91 errno))
92 return false;
93
94 /* Check the value of the newly created element */
95 if (CHECK(lookup_val.value != val.value, "bpf_map_lookup_elem",
96 "value got = %x errno:%d", lookup_val.value, val.value))
97 return false;
98
99 err = bpf_map_delete_elem(map_fd, &obj_fd);
100 if (CHECK(err, "bpf_map_delete_elem()", "err:%d errno:%d\n", err,
101 errno))
102 return false;
103
104 /* The lookup should fail, now that the element has been deleted */
105 err = bpf_map_lookup_elem_flags(map_fd, &obj_fd, &lookup_val,
106 BPF_F_LOCK);
107 if (CHECK(!err || errno != ENOENT, "bpf_map_lookup_elem",
108 "err:%d errno:%d\n", err, errno))
109 return false;
110
111 return true;
112}
113
114void test_test_local_storage(void)
115{
116 char tmp_dir_path[] = "/tmp/local_storageXXXXXX";
117 int err, serv_sk = -1, task_fd = -1, rm_fd = -1;
118 struct local_storage *skel = NULL;
119 char tmp_exec_path[64];
120 char cmd[256];
121
122 skel = local_storage__open_and_load();
123 if (CHECK(!skel, "skel_load", "lsm skeleton failed\n"))
124 goto close_prog;
125
126 err = local_storage__attach(skel);
127 if (CHECK(err, "attach", "lsm attach failed: %d\n", err))
128 goto close_prog;
129
130 task_fd = sys_pidfd_open(getpid(), 0);
131 if (CHECK(task_fd < 0, "pidfd_open",
132 "failed to get pidfd err:%d, errno:%d", task_fd, errno))
133 goto close_prog;
134
135 if (!check_syscall_operations(bpf_map__fd(skel->maps.task_storage_map),
136 task_fd))
137 goto close_prog;
138
139 if (CHECK(!mkdtemp(tmp_dir_path), "mkdtemp",
140 "unable to create tmpdir: %d\n", errno))
141 goto close_prog;
142
143 snprintf(tmp_exec_path, sizeof(tmp_exec_path), "%s/copy_of_rm",
144 tmp_dir_path);
145 snprintf(cmd, sizeof(cmd), "cp /bin/rm %s", tmp_exec_path);
146 if (CHECK_FAIL(system(cmd)))
147 goto close_prog_rmdir;
148
149 rm_fd = open(tmp_exec_path, O_RDONLY);
150 if (CHECK(rm_fd < 0, "open", "failed to open %s err:%d, errno:%d",
151 tmp_exec_path, rm_fd, errno))
152 goto close_prog_rmdir;
153
154 if (!check_syscall_operations(bpf_map__fd(skel->maps.inode_storage_map),
155 rm_fd))
156 goto close_prog_rmdir;
157
158 /* Sets skel->bss->monitored_pid to the pid of the forked child
159 * forks a child process that executes tmp_exec_path and tries to
160 * unlink its executable. This operation should be denied by the loaded
161 * LSM program.
162 */
163 err = run_self_unlink(&skel->bss->monitored_pid, tmp_exec_path);
164 if (CHECK(err != EPERM, "run_self_unlink", "err %d want EPERM\n", err))
165 goto close_prog_rmdir;
166
167 /* Set the process being monitored to be the current process */
168 skel->bss->monitored_pid = getpid();
169
170 /* Move copy_of_rm to a new location so that it triggers the
171 * inode_rename LSM hook with a new_dentry that has a NULL inode ptr.
172 */
173 snprintf(cmd, sizeof(cmd), "mv %s/copy_of_rm %s/check_null_ptr",
174 tmp_dir_path, tmp_dir_path);
175 if (CHECK_FAIL(system(cmd)))
176 goto close_prog_rmdir;
177
178 CHECK(skel->data->inode_storage_result != 0, "inode_storage_result",
179 "inode_local_storage not set\n");
180
181 serv_sk = start_server(AF_INET6, SOCK_STREAM, NULL, 0, 0);
182 if (CHECK(serv_sk < 0, "start_server", "failed to start server\n"))
183 goto close_prog_rmdir;
184
185 CHECK(skel->data->sk_storage_result != 0, "sk_storage_result",
186 "sk_local_storage not set\n");
187
188 if (!check_syscall_operations(bpf_map__fd(skel->maps.sk_storage_map),
189 serv_sk))
190 goto close_prog_rmdir;
191
192close_prog_rmdir:
193 snprintf(cmd, sizeof(cmd), "rm -rf %s", tmp_dir_path);
194 system(cmd);
195close_prog:
196 close(serv_sk);
197 close(rm_fd);
198 close(task_fd);
199 local_storage__destroy(skel);
200}