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cneiraAlexei Starovoitov
cneira
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Alexei Starovoitov
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tools/testing/selftests/bpf: Add self-tests for new helper bpf_get_ns_current_pid_tgid.
Self tests added for new helper bpf_get_ns_current_pid_tgid Signed-off-by: Carlos Neira <cneirabustos@gmail.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20200304204157.58695-4-cneirabustos@gmail.com
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‎tools/testing/selftests/bpf/.gitignore‎

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@@ -31,6 +31,7 @@ test_tcp_check_syncookie_user
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test_sysctl
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test_hashmap
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test_btf_dump
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test_current_pid_tgid_new_ns
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xdping
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test_cpp
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*.skel.h

‎tools/testing/selftests/bpf/Makefile‎

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@@ -32,7 +32,8 @@ TEST_GEN_PROGS = test_verifier test_tag test_maps test_lru_map test_lpm_map test
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test_sock test_btf test_sockmap get_cgroup_id_user test_socket_cookie \
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test_cgroup_storage \
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test_netcnt test_tcpnotify_user test_sock_fields test_sysctl test_hashmap \
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test_progs-no_alu32
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test_progs-no_alu32 \
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test_current_pid_tgid_new_ns
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# Also test bpf-gcc, if present
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ifneq ($(BPF_GCC),)

‎tools/testing/selftests/bpf/prog_tests/ns_current_pid_tgid.c‎

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// SPDX-License-Identifier: GPL-2.0
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/* Copyright (c) 2020 Carlos Neira cneirabustos@gmail.com */
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#include <test_progs.h>
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#include <sys/stat.h>
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#include <sys/types.h>
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#include <unistd.h>
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#include <sys/syscall.h>
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struct bss {
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__u64 dev;
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__u64 ino;
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__u64 pid_tgid;
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__u64 user_pid_tgid;
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};
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void test_ns_current_pid_tgid(void)
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{
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const char *probe_name = "raw_tracepoint/sys_enter";
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const char *file = "test_ns_current_pid_tgid.o";
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int err, key = 0, duration = 0;
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struct bpf_link *link = NULL;
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struct bpf_program *prog;
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struct bpf_map *bss_map;
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struct bpf_object *obj;
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struct bss bss;
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struct stat st;
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__u64 id;
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obj = bpf_object__open_file(file, NULL);
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if (CHECK(IS_ERR(obj), "obj_open", "err %ld\n", PTR_ERR(obj)))
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return;
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err = bpf_object__load(obj);
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if (CHECK(err, "obj_load", "err %d errno %d\n", err, errno))
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goto cleanup;
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bss_map = bpf_object__find_map_by_name(obj, "test_ns_.bss");
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if (CHECK(!bss_map, "find_bss_map", "failed\n"))
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goto cleanup;
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prog = bpf_object__find_program_by_title(obj, probe_name);
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if (CHECK(!prog, "find_prog", "prog '%s' not found\n",
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probe_name))
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goto cleanup;
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memset(&bss, 0, sizeof(bss));
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pid_t tid = syscall(SYS_gettid);
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pid_t pid = getpid();
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id = (__u64) tid << 32 | pid;
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bss.user_pid_tgid = id;
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if (CHECK_FAIL(stat("/proc/self/ns/pid", &st))) {
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perror("Failed to stat /proc/self/ns/pid");
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goto cleanup;
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}
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bss.dev = st.st_dev;
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bss.ino = st.st_ino;
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err = bpf_map_update_elem(bpf_map__fd(bss_map), &key, &bss, 0);
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if (CHECK(err, "setting_bss", "failed to set bss : %d\n", err))
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goto cleanup;
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link = bpf_program__attach_raw_tracepoint(prog, "sys_enter");
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if (CHECK(IS_ERR(link), "attach_raw_tp", "err %ld\n",
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PTR_ERR(link))) {
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link = NULL;
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goto cleanup;
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}
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/* trigger some syscalls */
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usleep(1);
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err = bpf_map_lookup_elem(bpf_map__fd(bss_map), &key, &bss);
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if (CHECK(err, "set_bss", "failed to get bss : %d\n", err))
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goto cleanup;
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if (CHECK(id != bss.pid_tgid, "Compare user pid/tgid vs. bpf pid/tgid",
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"User pid/tgid %llu BPF pid/tgid %llu\n", id, bss.pid_tgid))
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goto cleanup;
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cleanup:
83+
if (!link) {
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bpf_link__destroy(link);
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link = NULL;
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}
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bpf_object__close(obj);
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}

‎tools/testing/selftests/bpf/progs/test_ns_current_pid_tgid.c‎

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@@ -0,0 +1,37 @@
1+
// SPDX-License-Identifier: GPL-2.0
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/* Copyright (c) 2019 Carlos Neira cneirabustos@gmail.com */
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4+
#include <linux/bpf.h>
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#include <stdint.h>
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#include <bpf/bpf_helpers.h>
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static volatile struct {
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__u64 dev;
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__u64 ino;
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__u64 pid_tgid;
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__u64 user_pid_tgid;
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} res;
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SEC("raw_tracepoint/sys_enter")
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int trace(void *ctx)
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{
18+
__u64 ns_pid_tgid, expected_pid;
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struct bpf_pidns_info nsdata;
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__u32 key = 0;
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if (bpf_get_ns_current_pid_tgid(res.dev, res.ino, &nsdata,
23+
sizeof(struct bpf_pidns_info)))
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return 0;
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ns_pid_tgid = (__u64)nsdata.tgid << 32 | nsdata.pid;
27+
expected_pid = res.user_pid_tgid;
28+
29+
if (expected_pid != ns_pid_tgid)
30+
return 0;
31+
32+
res.pid_tgid = ns_pid_tgid;
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34+
return 0;
35+
}
36+
37+
char _license[] SEC("license") = "GPL";

‎tools/testing/selftests/bpf/test_current_pid_tgid_new_ns.c‎

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@@ -0,0 +1,159 @@
1+
// SPDX-License-Identifier: GPL-2.0
2+
/* Copyright (c) 2020 Carlos Neira cneirabustos@gmail.com */
3+
#define _GNU_SOURCE
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#include <sys/stat.h>
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#include <sys/types.h>
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#include <unistd.h>
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#include <sys/syscall.h>
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#include <sched.h>
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#include <sys/wait.h>
10+
#include <sys/mount.h>
11+
#include "test_progs.h"
12+
13+
#define CHECK_NEWNS(condition, tag, format...) ({ \
14+
int __ret = !!(condition); \
15+
if (__ret) { \
16+
printf("%s:FAIL:%s ", __func__, tag); \
17+
printf(format); \
18+
} else { \
19+
printf("%s:PASS:%s\n", __func__, tag); \
20+
} \
21+
__ret; \
22+
})
23+
24+
struct bss {
25+
__u64 dev;
26+
__u64 ino;
27+
__u64 pid_tgid;
28+
__u64 user_pid_tgid;
29+
};
30+
31+
int main(int argc, char **argv)
32+
{
33+
pid_t pid;
34+
int exit_code = 1;
35+
struct stat st;
36+
37+
printf("Testing bpf_get_ns_current_pid_tgid helper in new ns\n");
38+
39+
if (stat("/proc/self/ns/pid", &st)) {
40+
perror("stat failed on /proc/self/ns/pid ns\n");
41+
printf("%s:FAILED\n", argv[0]);
42+
return exit_code;
43+
}
44+
45+
if (CHECK_NEWNS(unshare(CLONE_NEWPID | CLONE_NEWNS),
46+
"unshare CLONE_NEWPID | CLONE_NEWNS", "error errno=%d\n", errno))
47+
return exit_code;
48+
49+
pid = fork();
50+
if (pid == -1) {
51+
perror("Fork() failed\n");
52+
printf("%s:FAILED\n", argv[0]);
53+
return exit_code;
54+
}
55+
56+
if (pid > 0) {
57+
int status;
58+
59+
usleep(5);
60+
waitpid(pid, &status, 0);
61+
return 0;
62+
} else {
63+
64+
pid = fork();
65+
if (pid == -1) {
66+
perror("Fork() failed\n");
67+
printf("%s:FAILED\n", argv[0]);
68+
return exit_code;
69+
}
70+
71+
if (pid > 0) {
72+
int status;
73+
waitpid(pid, &status, 0);
74+
return 0;
75+
} else {
76+
if (CHECK_NEWNS(mount("none", "/proc", NULL, MS_PRIVATE|MS_REC, NULL),
77+
"Unmounting proc", "Cannot umount proc! errno=%d\n", errno))
78+
return exit_code;
79+
80+
if (CHECK_NEWNS(mount("proc", "/proc", "proc", MS_NOSUID|MS_NOEXEC|MS_NODEV, NULL),
81+
"Mounting proc", "Cannot mount proc! errno=%d\n", errno))
82+
return exit_code;
83+
84+
const char *probe_name = "raw_tracepoint/sys_enter";
85+
const char *file = "test_ns_current_pid_tgid.o";
86+
struct bpf_link *link = NULL;
87+
struct bpf_program *prog;
88+
struct bpf_map *bss_map;
89+
struct bpf_object *obj;
90+
int exit_code = 1;
91+
int err, key = 0;
92+
struct bss bss;
93+
struct stat st;
94+
__u64 id;
95+
96+
obj = bpf_object__open_file(file, NULL);
97+
if (CHECK_NEWNS(IS_ERR(obj), "obj_open", "err %ld\n", PTR_ERR(obj)))
98+
return exit_code;
99+
100+
err = bpf_object__load(obj);
101+
if (CHECK_NEWNS(err, "obj_load", "err %d errno %d\n", err, errno))
102+
goto cleanup;
103+
104+
bss_map = bpf_object__find_map_by_name(obj, "test_ns_.bss");
105+
if (CHECK_NEWNS(!bss_map, "find_bss_map", "failed\n"))
106+
goto cleanup;
107+
108+
prog = bpf_object__find_program_by_title(obj, probe_name);
109+
if (CHECK_NEWNS(!prog, "find_prog", "prog '%s' not found\n",
110+
probe_name))
111+
goto cleanup;
112+
113+
memset(&bss, 0, sizeof(bss));
114+
pid_t tid = syscall(SYS_gettid);
115+
pid_t pid = getpid();
116+
117+
id = (__u64) tid << 32 | pid;
118+
bss.user_pid_tgid = id;
119+
120+
if (CHECK_NEWNS(stat("/proc/self/ns/pid", &st),
121+
"stat new ns", "Failed to stat /proc/self/ns/pid errno=%d\n", errno))
122+
goto cleanup;
123+
124+
bss.dev = st.st_dev;
125+
bss.ino = st.st_ino;
126+
127+
err = bpf_map_update_elem(bpf_map__fd(bss_map), &key, &bss, 0);
128+
if (CHECK_NEWNS(err, "setting_bss", "failed to set bss : %d\n", err))
129+
goto cleanup;
130+
131+
link = bpf_program__attach_raw_tracepoint(prog, "sys_enter");
132+
if (CHECK_NEWNS(IS_ERR(link), "attach_raw_tp", "err %ld\n",
133+
PTR_ERR(link))) {
134+
link = NULL;
135+
goto cleanup;
136+
}
137+
138+
/* trigger some syscalls */
139+
usleep(1);
140+
141+
err = bpf_map_lookup_elem(bpf_map__fd(bss_map), &key, &bss);
142+
if (CHECK_NEWNS(err, "set_bss", "failed to get bss : %d\n", err))
143+
goto cleanup;
144+
145+
if (CHECK_NEWNS(id != bss.pid_tgid, "Compare user pid/tgid vs. bpf pid/tgid",
146+
"User pid/tgid %llu BPF pid/tgid %llu\n", id, bss.pid_tgid))
147+
goto cleanup;
148+
149+
exit_code = 0;
150+
printf("%s:PASS\n", argv[0]);
151+
cleanup:
152+
if (!link) {
153+
bpf_link__destroy(link);
154+
link = NULL;
155+
}
156+
bpf_object__close(obj);
157+
}
158+
}
159+
}

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