1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
|
// SPDX-License-Identifier: GPL-2.0
// Copyright (c) 2018 Facebook
#include <stdio.h>
#include <unistd.h>
#include <arpa/inet.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <linux/filter.h>
#include <bpf/bpf.h>
#include "cgroup_helpers.h"
#include "bpf_rlimit.h"
#include "bpf_util.h"
#define CG_PATH "/foo"
#define MAX_INSNS 512
char bpf_log_buf[BPF_LOG_BUF_SIZE];
struct sock_test {
const char *descr;
/* BPF prog properties */
struct bpf_insn insns[MAX_INSNS];
enum bpf_attach_type expected_attach_type;
enum bpf_attach_type attach_type;
/* Socket properties */
int domain;
int type;
/* Endpoint to bind() to */
const char *ip;
unsigned short port;
/* Expected test result */
enum {
LOAD_REJECT,
ATTACH_REJECT,
BIND_REJECT,
SUCCESS,
} result;
};
static struct sock_test tests[] = {
{
"bind4 load with invalid access: src_ip6",
.insns = {
BPF_MOV64_REG(BPF_REG_6, BPF_REG_1),
BPF_LDX_MEM(BPF_W, BPF_REG_7, BPF_REG_6,
offsetof(struct bpf_sock, src_ip6[0])),
BPF_MOV64_IMM(BPF_REG_0, 1),
BPF_EXIT_INSN(),
},
BPF_CGROUP_INET4_POST_BIND,
BPF_CGROUP_INET4_POST_BIND,
0,
0,
NULL,
0,
LOAD_REJECT,
},
{
"bind4 load with invalid access: mark",
.insns = {
BPF_MOV64_REG(BPF_REG_6, BPF_REG_1),
BPF_LDX_MEM(BPF_W, BPF_REG_7, BPF_REG_6,
offsetof(struct bpf_sock, mark)),
BPF_MOV64_IMM(BPF_REG_0, 1),
BPF_EXIT_INSN(),
},
BPF_CGROUP_INET4_POST_BIND,
BPF_CGROUP_INET4_POST_BIND,
0,
0,
NULL,
0,
LOAD_REJECT,
},
{
"bind6 load with invalid access: src_ip4",
.insns = {
BPF_MOV64_REG(BPF_REG_6, BPF_REG_1),
BPF_LDX_MEM(BPF_W, BPF_REG_7, BPF_REG_6,
offsetof(struct bpf_sock, src_ip4)),
BPF_MOV64_IMM(BPF_REG_0, 1),
BPF_EXIT_INSN(),
},
BPF_CGROUP_INET6_POST_BIND,
BPF_CGROUP_INET6_POST_BIND,
0,
0,
NULL,
0,
LOAD_REJECT,
},
{
"sock_create load with invalid access: src_port",
.insns = {
BPF_MOV64_REG(BPF_REG_6, BPF_REG_1),
BPF_LDX_MEM(BPF_W, BPF_REG_7, BPF_REG_6,
offsetof(struct bpf_sock, src_port)),
BPF_MOV64_IMM(BPF_REG_0, 1),
BPF_EXIT_INSN(),
},
BPF_CGROUP_INET_SOCK_CREATE,
BPF_CGROUP_INET_SOCK_CREATE,
0,
0,
NULL,
0,
LOAD_REJECT,
},
{
"sock_create load w/o expected_attach_type (compat mode)",
.insns = {
BPF_MOV64_IMM(BPF_REG_0, 1),
BPF_EXIT_INSN(),
},
0,
BPF_CGROUP_INET_SOCK_CREATE,
AF_INET,
SOCK_STREAM,
"127.0.0.1",
8097,
SUCCESS,
},
{
"sock_create load w/ expected_attach_type",
.insns = {
BPF_MOV64_IMM(BPF_REG_0, 1),
BPF_EXIT_INSN(),
},
BPF_CGROUP_INET_SOCK_CREATE,
BPF_CGROUP_INET_SOCK_CREATE,
AF_INET,
SOCK_STREAM,
"127.0.0.1",
8097,
SUCCESS,
},
{
"attach type mismatch bind4 vs bind6",
.insns = {
BPF_MOV64_IMM(BPF_REG_0, 1),
BPF_EXIT_INSN(),
},
BPF_CGROUP_INET4_POST_BIND,
BPF_CGROUP_INET6_POST_BIND,
0,
0,
NULL,
0,
ATTACH_REJECT,
},
{
"attach type mismatch bind6 vs bind4",
.insns = {
BPF_MOV64_IMM(BPF_REG_0, 1),
BPF_EXIT_INSN(),
},
BPF_CGROUP_INET6_POST_BIND,
BPF_CGROUP_INET4_POST_BIND,
0,
0,
NULL,
0,
ATTACH_REJECT,
},
{
"attach type mismatch default vs bind4",
.insns = {
BPF_MOV64_IMM(BPF_REG_0, 1),
BPF_EXIT_INSN(),
},
0,
BPF_CGROUP_INET4_POST_BIND,
0,
0,
NULL,
0,
ATTACH_REJECT,
},
{
"attach type mismatch bind6 vs sock_create",
.insns = {
BPF_MOV64_IMM(BPF_REG_0, 1),
BPF_EXIT_INSN(),
},
BPF_CGROUP_INET6_POST_BIND,
BPF_CGROUP_INET_SOCK_CREATE,
0,
0,
NULL,
0,
ATTACH_REJECT,
},
{
"bind4 reject all",
.insns = {
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
BPF_CGROUP_INET4_POST_BIND,
BPF_CGROUP_INET4_POST_BIND,
AF_INET,
SOCK_STREAM,
"0.0.0.0",
0,
BIND_REJECT,
},
{
"bind6 reject all",
.insns = {
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
BPF_CGROUP_INET6_POST_BIND,
BPF_CGROUP_INET6_POST_BIND,
AF_INET6,
SOCK_STREAM,
"::",
0,
BIND_REJECT,
},
{
"bind6 deny specific IP & port",
.insns = {
BPF_MOV64_REG(BPF_REG_6, BPF_REG_1),
/* if (ip == expected && port == expected) */
BPF_LDX_MEM(BPF_W, BPF_REG_7, BPF_REG_6,
offsetof(struct bpf_sock, src_ip6[3])),
BPF_JMP_IMM(BPF_JNE, BPF_REG_7, 0x01000000, 4),
BPF_LDX_MEM(BPF_W, BPF_REG_7, BPF_REG_6,
offsetof(struct bpf_sock, src_port)),
BPF_JMP_IMM(BPF_JNE, BPF_REG_7, 0x2001, 2),
/* return DENY; */
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_JMP_A(1),
/* else return ALLOW; */
BPF_MOV64_IMM(BPF_REG_0, 1),
BPF_EXIT_INSN(),
},
BPF_CGROUP_INET6_POST_BIND,
BPF_CGROUP_INET6_POST_BIND,
AF_INET6,
SOCK_STREAM,
"::1",
8193,
BIND_REJECT,
},
{
"bind4 allow specific IP & port",
.insns = {
BPF_MOV64_REG(BPF_REG_6, BPF_REG_1),
/* if (ip == expected && port == expected) */
BPF_LDX_MEM(BPF_W, BPF_REG_7, BPF_REG_6,
offsetof(struct bpf_sock, src_ip4)),
BPF_JMP_IMM(BPF_JNE, BPF_REG_7, 0x0100007F, 4),
BPF_LDX_MEM(BPF_W, BPF_REG_7, BPF_REG_6,
offsetof(struct bpf_sock, src_port)),
BPF_JMP_IMM(BPF_JNE, BPF_REG_7, 0x1002, 2),
/* return ALLOW; */
BPF_MOV64_IMM(BPF_REG_0, 1),
BPF_JMP_A(1),
/* else return DENY; */
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
BPF_CGROUP_INET4_POST_BIND,
BPF_CGROUP_INET4_POST_BIND,
AF_INET,
SOCK_STREAM,
"127.0.0.1",
4098,
SUCCESS,
},
{
"bind4 allow all",
.insns = {
BPF_MOV64_IMM(BPF_REG_0, 1),
BPF_EXIT_INSN(),
},
BPF_CGROUP_INET4_POST_BIND,
BPF_CGROUP_INET4_POST_BIND,
AF_INET,
SOCK_STREAM,
"0.0.0.0",
0,
SUCCESS,
},
{
"bind6 allow all",
.insns = {
BPF_MOV64_IMM(BPF_REG_0, 1),
BPF_EXIT_INSN(),
},
BPF_CGROUP_INET6_POST_BIND,
BPF_CGROUP_INET6_POST_BIND,
AF_INET6,
SOCK_STREAM,
"::",
0,
SUCCESS,
},
};
static size_t probe_prog_length(const struct bpf_insn *fp)
{
size_t len;
for (len = MAX_INSNS - 1; len > 0; --len)
if (fp[len].code != 0 || fp[len].imm != 0)
break;
return len + 1;
}
static int load_sock_prog(const struct bpf_insn *prog,
enum bpf_attach_type attach_type)
{
struct bpf_load_program_attr attr;
memset(&attr, 0, sizeof(struct bpf_load_program_attr));
attr.prog_type = BPF_PROG_TYPE_CGROUP_SOCK;
attr.expected_attach_type = attach_type;
attr.insns = prog;
attr.insns_cnt = probe_prog_length(attr.insns);
attr.license = "GPL";
return bpf_load_program_xattr(&attr, bpf_log_buf, BPF_LOG_BUF_SIZE);
}
static int attach_sock_prog(int cgfd, int progfd,
enum bpf_attach_type attach_type)
{
return bpf_prog_attach(progfd, cgfd, attach_type, BPF_F_ALLOW_OVERRIDE);
}
static int bind_sock(int domain, int type, const char *ip, unsigned short port)
{
struct sockaddr_storage addr;
struct sockaddr_in6 *addr6;
struct sockaddr_in *addr4;
int sockfd = -1;
socklen_t len;
int err = 0;
sockfd = socket(domain, type, 0);
if (sockfd < 0)
goto err;
memset(&addr, 0, sizeof(addr));
if (domain == AF_INET) {
len = sizeof(struct sockaddr_in);
addr4 = (struct sockaddr_in *)&addr;
addr4->sin_family = domain;
addr4->sin_port = htons(port);
if (inet_pton(domain, ip, (void *)&addr4->sin_addr) != 1)
goto err;
} else if (domain == AF_INET6) {
len = sizeof(struct sockaddr_in6);
addr6 = (struct sockaddr_in6 *)&addr;
addr6->sin6_family = domain;
addr6->sin6_port = htons(port);
if (inet_pton(domain, ip, (void *)&addr6->sin6_addr) != 1)
goto err;
} else {
goto err;
}
if (bind(sockfd, (const struct sockaddr *)&addr, len) == -1)
goto err;
goto out;
err:
err = -1;
out:
close(sockfd);
return err;
}
static int run_test_case(int cgfd, const struct sock_test *test)
{
int progfd = -1;
int err = 0;
printf("Test case: %s .. ", test->descr);
progfd = load_sock_prog(test->insns, test->expected_attach_type);
if (progfd < 0) {
if (test->result == LOAD_REJECT)
goto out;
else
goto err;
}
if (attach_sock_prog(cgfd, progfd, test->attach_type) == -1) {
if (test->result == ATTACH_REJECT)
goto out;
else
goto err;
}
if (bind_sock(test->domain, test->type, test->ip, test->port) == -1) {
/* sys_bind() may fail for different reasons, errno has to be
* checked to confirm that BPF program rejected it.
*/
if (test->result == BIND_REJECT && errno == EPERM)
goto out;
else
goto err;
}
if (test->result != SUCCESS)
goto err;
goto out;
err:
err = -1;
out:
/* Detaching w/o checking return code: best effort attempt. */
if (progfd != -1)
bpf_prog_detach(cgfd, test->attach_type);
close(progfd);
printf("[%s]\n", err ? "FAIL" : "PASS");
return err;
}
static int run_tests(int cgfd)
{
int passes = 0;
int fails = 0;
int i;
for (i = 0; i < ARRAY_SIZE(tests); ++i) {
if (run_test_case(cgfd, &tests[i]))
++fails;
else
++passes;
}
printf("Summary: %d PASSED, %d FAILED\n", passes, fails);
return fails ? -1 : 0;
}
int main(int argc, char **argv)
{
int cgfd = -1;
int err = 0;
if (setup_cgroup_environment())
goto err;
cgfd = create_and_get_cgroup(CG_PATH);
if (cgfd < 0)
goto err;
if (join_cgroup(CG_PATH))
goto err;
if (run_tests(cgfd))
goto err;
goto out;
err:
err = -1;
out:
close(cgfd);
cleanup_cgroup_environment();
return err;
}
|
