Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
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#include "test_d_path_check_rdonly_mem.skel.h"
13#include "test_d_path_check_types.skel.h"
14
15/* sys_close_range is not around for long time, so let's
16 * make sure we can call it on systems with older glibc
17 */
18#ifndef __NR_close_range
19#ifdef __alpha__
20#define __NR_close_range 546
21#else
22#define __NR_close_range 436
23#endif
24#endif
25
26static int duration;
27
28static struct {
29 __u32 cnt;
30 char paths[MAX_FILES][MAX_PATH_LEN];
31} src;
32
33static int set_pathname(int fd, pid_t pid)
34{
35 char buf[MAX_PATH_LEN];
36
37 snprintf(buf, MAX_PATH_LEN, "/proc/%d/fd/%d", pid, fd);
38 return readlink(buf, src.paths[src.cnt++], MAX_PATH_LEN);
39}
40
41static inline long syscall_close(int fd)
42{
43 return syscall(__NR_close_range,
44 (unsigned int)fd,
45 (unsigned int)fd,
46 0u);
47}
48
49static int trigger_fstat_events(pid_t pid)
50{
51 int sockfd = -1, procfd = -1, devfd = -1;
52 int localfd = -1, indicatorfd = -1;
53 int pipefd[2] = { -1, -1 };
54 struct stat fileStat;
55 int ret = -1;
56
57 /* unmountable pseudo-filesystems */
58 if (CHECK(pipe(pipefd) < 0, "trigger", "pipe failed\n"))
59 return ret;
60 /* unmountable pseudo-filesystems */
61 sockfd = socket(AF_INET, SOCK_STREAM, 0);
62 if (CHECK(sockfd < 0, "trigger", "socket failed\n"))
63 goto out_close;
64 /* mountable pseudo-filesystems */
65 procfd = open("/proc/self/comm", O_RDONLY);
66 if (CHECK(procfd < 0, "trigger", "open /proc/self/comm failed\n"))
67 goto out_close;
68 devfd = open("/dev/urandom", O_RDONLY);
69 if (CHECK(devfd < 0, "trigger", "open /dev/urandom failed\n"))
70 goto out_close;
71 localfd = open("/tmp/d_path_loadgen.txt", O_CREAT | O_RDONLY, 0644);
72 if (CHECK(localfd < 0, "trigger", "open /tmp/d_path_loadgen.txt failed\n"))
73 goto out_close;
74 /* bpf_d_path will return path with (deleted) */
75 remove("/tmp/d_path_loadgen.txt");
76 indicatorfd = open("/tmp/", O_PATH);
77 if (CHECK(indicatorfd < 0, "trigger", "open /tmp/ failed\n"))
78 goto out_close;
79
80 ret = set_pathname(pipefd[0], pid);
81 if (CHECK(ret < 0, "trigger", "set_pathname failed for pipe[0]\n"))
82 goto out_close;
83 ret = set_pathname(pipefd[1], pid);
84 if (CHECK(ret < 0, "trigger", "set_pathname failed for pipe[1]\n"))
85 goto out_close;
86 ret = set_pathname(sockfd, pid);
87 if (CHECK(ret < 0, "trigger", "set_pathname failed for socket\n"))
88 goto out_close;
89 ret = set_pathname(procfd, pid);
90 if (CHECK(ret < 0, "trigger", "set_pathname failed for proc\n"))
91 goto out_close;
92 ret = set_pathname(devfd, pid);
93 if (CHECK(ret < 0, "trigger", "set_pathname failed for dev\n"))
94 goto out_close;
95 ret = set_pathname(localfd, pid);
96 if (CHECK(ret < 0, "trigger", "set_pathname failed for file\n"))
97 goto out_close;
98 ret = set_pathname(indicatorfd, pid);
99 if (CHECK(ret < 0, "trigger", "set_pathname failed for dir\n"))
100 goto out_close;
101
102 /* triggers vfs_getattr */
103 fstat(pipefd[0], &fileStat);
104 fstat(pipefd[1], &fileStat);
105 fstat(sockfd, &fileStat);
106 fstat(procfd, &fileStat);
107 fstat(devfd, &fileStat);
108 fstat(localfd, &fileStat);
109 fstat(indicatorfd, &fileStat);
110
111out_close:
112 /* sys_close no longer triggers filp_close, but we can
113 * call sys_close_range instead which still does
114 */
115 syscall_close(pipefd[0]);
116 syscall_close(pipefd[1]);
117 syscall_close(sockfd);
118 syscall_close(procfd);
119 syscall_close(devfd);
120 syscall_close(localfd);
121 syscall_close(indicatorfd);
122 return ret;
123}
124
125static void attach_and_load(struct test_d_path **skel)
126{
127 int err;
128
129 *skel = test_d_path__open_and_load();
130 if (CHECK(!*skel, "setup", "d_path skeleton failed\n"))
131 goto cleanup;
132
133 err = test_d_path__attach(*skel);
134 if (CHECK(err, "setup", "attach failed: %d\n", err))
135 goto cleanup;
136
137 (*skel)->bss->my_pid = getpid();
138 return;
139
140cleanup:
141 test_d_path__destroy(*skel);
142 *skel = NULL;
143}
144
145static void test_d_path_basic(void)
146{
147 struct test_d_path__bss *bss;
148 struct test_d_path *skel;
149 int err;
150
151 attach_and_load(&skel);
152 if (!skel)
153 goto cleanup;
154
155 bss = skel->bss;
156
157 err = trigger_fstat_events(bss->my_pid);
158 if (err < 0)
159 goto cleanup;
160
161 if (CHECK(!bss->called_stat,
162 "stat",
163 "trampoline for security_inode_getattr was not called\n"))
164 goto cleanup;
165
166 if (CHECK(!bss->called_close,
167 "close",
168 "trampoline for filp_close was not called\n"))
169 goto cleanup;
170
171 for (int i = 0; i < MAX_FILES; i++) {
172 CHECK(strncmp(src.paths[i], bss->paths_stat[i], MAX_PATH_LEN),
173 "check",
174 "failed to get stat path[%d]: %s vs %s\n",
175 i, src.paths[i], bss->paths_stat[i]);
176 CHECK(strncmp(src.paths[i], bss->paths_close[i], MAX_PATH_LEN),
177 "check",
178 "failed to get close path[%d]: %s vs %s\n",
179 i, src.paths[i], bss->paths_close[i]);
180 /* The d_path helper returns size plus NUL char, hence + 1 */
181 CHECK(bss->rets_stat[i] != strlen(bss->paths_stat[i]) + 1,
182 "check",
183 "failed to match stat return [%d]: %d vs %zd [%s]\n",
184 i, bss->rets_stat[i], strlen(bss->paths_stat[i]) + 1,
185 bss->paths_stat[i]);
186 CHECK(bss->rets_close[i] != strlen(bss->paths_stat[i]) + 1,
187 "check",
188 "failed to match stat return [%d]: %d vs %zd [%s]\n",
189 i, bss->rets_close[i], strlen(bss->paths_close[i]) + 1,
190 bss->paths_stat[i]);
191 }
192
193cleanup:
194 test_d_path__destroy(skel);
195}
196
197static void test_d_path_check_rdonly_mem(void)
198{
199 struct test_d_path_check_rdonly_mem *skel;
200
201 skel = test_d_path_check_rdonly_mem__open_and_load();
202 ASSERT_ERR_PTR(skel, "unexpected_load_overwriting_rdonly_mem");
203
204 test_d_path_check_rdonly_mem__destroy(skel);
205}
206
207static void test_d_path_check_types(void)
208{
209 struct test_d_path_check_types *skel;
210
211 skel = test_d_path_check_types__open_and_load();
212 ASSERT_ERR_PTR(skel, "unexpected_load_passing_wrong_type");
213
214 test_d_path_check_types__destroy(skel);
215}
216
217/* Check if the verifier correctly generates code for
218 * accessing the memory modified by d_path helper.
219 */
220static void test_d_path_mem_access(void)
221{
222 int localfd = -1;
223 char path_template[] = "/dev/shm/d_path_loadgen.XXXXXX";
224 struct test_d_path__bss *bss;
225 struct test_d_path *skel;
226
227 attach_and_load(&skel);
228 if (!skel)
229 goto cleanup;
230
231 bss = skel->bss;
232
233 localfd = mkstemp(path_template);
234 if (CHECK(localfd < 0, "trigger", "mkstemp failed\n"))
235 goto cleanup;
236
237 if (CHECK(fallocate(localfd, 0, 0, 1024) < 0, "trigger", "fallocate failed\n"))
238 goto cleanup;
239 remove(path_template);
240
241 if (CHECK(!bss->path_match_fallocate, "check",
242 "failed to read fallocate path"))
243 goto cleanup;
244
245cleanup:
246 syscall_close(localfd);
247 test_d_path__destroy(skel);
248}
249
250void test_d_path(void)
251{
252 if (test__start_subtest("basic"))
253 test_d_path_basic();
254
255 if (test__start_subtest("check_rdonly_mem"))
256 test_d_path_check_rdonly_mem();
257
258 if (test__start_subtest("check_alloc_mem"))
259 test_d_path_check_types();
260
261 if (test__start_subtest("check_mem_access"))
262 test_d_path_mem_access();
263}