1 // SPDX-License-Identifier: GPL-2.0
2 // Copyright (c) 2018 Facebook
3
4 #include <stdio.h>
5 #include <unistd.h>
6
7 #include <arpa/inet.h>
8 #include <sys/types.h>
9 #include <sys/socket.h>
10
11 #include <linux/filter.h>
12
13 #include <bpf/bpf.h>
14
15 #include "cgroup_helpers.h"
16 #include <bpf/bpf_endian.h>
17 #include "bpf_util.h"
18
19 #define CG_PATH "/foo"
20 #define MAX_INSNS 512
21
22 char bpf_log_buf[BPF_LOG_BUF_SIZE];
23 static bool verbose = false;
24
25 struct sock_test {
26 const char *descr;
27 /* BPF prog properties */
28 struct bpf_insn insns[MAX_INSNS];
29 enum bpf_attach_type expected_attach_type;
30 enum bpf_attach_type attach_type;
31 /* Socket properties */
32 int domain;
33 int type;
34 /* Endpoint to bind() to */
35 const char *ip;
36 unsigned short port;
37 unsigned short port_retry;
38 /* Expected test result */
39 enum {
40 LOAD_REJECT,
41 ATTACH_REJECT,
42 BIND_REJECT,
43 SUCCESS,
44 RETRY_SUCCESS,
45 RETRY_REJECT
46 } result;
47 };
48
49 static struct sock_test tests[] = {
50 {
51 .descr = "bind4 load with invalid access: src_ip6",
52 .insns = {
53 BPF_MOV64_REG(BPF_REG_6, BPF_REG_1),
54 BPF_LDX_MEM(BPF_W, BPF_REG_7, BPF_REG_6,
55 offsetof(struct bpf_sock, src_ip6[0])),
56 BPF_MOV64_IMM(BPF_REG_0, 1),
57 BPF_EXIT_INSN(),
58 },
59 .expected_attach_type = BPF_CGROUP_INET4_POST_BIND,
60 .attach_type = BPF_CGROUP_INET4_POST_BIND,
61 .result = LOAD_REJECT,
62 },
63 {
64 .descr = "bind4 load with invalid access: mark",
65 .insns = {
66 BPF_MOV64_REG(BPF_REG_6, BPF_REG_1),
67 BPF_LDX_MEM(BPF_W, BPF_REG_7, BPF_REG_6,
68 offsetof(struct bpf_sock, mark)),
69 BPF_MOV64_IMM(BPF_REG_0, 1),
70 BPF_EXIT_INSN(),
71 },
72 .expected_attach_type = BPF_CGROUP_INET4_POST_BIND,
73 .attach_type = BPF_CGROUP_INET4_POST_BIND,
74 .result = LOAD_REJECT,
75 },
76 {
77 .descr = "bind6 load with invalid access: src_ip4",
78 .insns = {
79 BPF_MOV64_REG(BPF_REG_6, BPF_REG_1),
80 BPF_LDX_MEM(BPF_W, BPF_REG_7, BPF_REG_6,
81 offsetof(struct bpf_sock, src_ip4)),
82 BPF_MOV64_IMM(BPF_REG_0, 1),
83 BPF_EXIT_INSN(),
84 },
85 .expected_attach_type = BPF_CGROUP_INET6_POST_BIND,
86 .attach_type = BPF_CGROUP_INET6_POST_BIND,
87 .result = LOAD_REJECT,
88 },
89 {
90 .descr = "sock_create load with invalid access: src_port",
91 .insns = {
92 BPF_MOV64_REG(BPF_REG_6, BPF_REG_1),
93 BPF_LDX_MEM(BPF_W, BPF_REG_7, BPF_REG_6,
94 offsetof(struct bpf_sock, src_port)),
95 BPF_MOV64_IMM(BPF_REG_0, 1),
96 BPF_EXIT_INSN(),
97 },
98 .expected_attach_type = BPF_CGROUP_INET_SOCK_CREATE,
99 .attach_type = BPF_CGROUP_INET_SOCK_CREATE,
100 .result = LOAD_REJECT,
101 },
102 {
103 .descr = "sock_create load w/o expected_attach_type (compat mode)",
104 .insns = {
105 BPF_MOV64_IMM(BPF_REG_0, 1),
106 BPF_EXIT_INSN(),
107 },
108 .expected_attach_type = 0,
109 .attach_type = BPF_CGROUP_INET_SOCK_CREATE,
110 .domain = AF_INET,
111 .type = SOCK_STREAM,
112 .ip = "127.0.0.1",
113 .port = 8097,
114 .result = SUCCESS,
115 },
116 {
117 .descr = "sock_create load w/ expected_attach_type",
118 .insns = {
119 BPF_MOV64_IMM(BPF_REG_0, 1),
120 BPF_EXIT_INSN(),
121 },
122 .expected_attach_type = BPF_CGROUP_INET_SOCK_CREATE,
123 .attach_type = BPF_CGROUP_INET_SOCK_CREATE,
124 .domain = AF_INET,
125 .type = SOCK_STREAM,
126 .ip = "127.0.0.1",
127 .port = 8097,
128 .result = SUCCESS,
129 },
130 {
131 .descr = "attach type mismatch bind4 vs bind6",
132 .insns = {
133 BPF_MOV64_IMM(BPF_REG_0, 1),
134 BPF_EXIT_INSN(),
135 },
136 .expected_attach_type = BPF_CGROUP_INET4_POST_BIND,
137 .attach_type = BPF_CGROUP_INET6_POST_BIND,
138 .result = ATTACH_REJECT,
139 },
140 {
141 .descr = "attach type mismatch bind6 vs bind4",
142 .insns = {
143 BPF_MOV64_IMM(BPF_REG_0, 1),
144 BPF_EXIT_INSN(),
145 },
146 .expected_attach_type = BPF_CGROUP_INET6_POST_BIND,
147 .attach_type = BPF_CGROUP_INET4_POST_BIND,
148 .result = ATTACH_REJECT,
149 },
150 {
151 .descr = "attach type mismatch default vs bind4",
152 .insns = {
153 BPF_MOV64_IMM(BPF_REG_0, 1),
154 BPF_EXIT_INSN(),
155 },
156 .expected_attach_type = 0,
157 .attach_type = BPF_CGROUP_INET4_POST_BIND,
158 .result = ATTACH_REJECT,
159 },
160 {
161 .descr = "attach type mismatch bind6 vs sock_create",
162 .insns = {
163 BPF_MOV64_IMM(BPF_REG_0, 1),
164 BPF_EXIT_INSN(),
165 },
166 .expected_attach_type = BPF_CGROUP_INET6_POST_BIND,
167 .attach_type = BPF_CGROUP_INET_SOCK_CREATE,
168 .result = ATTACH_REJECT,
169 },
170 {
171 .descr = "bind4 reject all",
172 .insns = {
173 BPF_MOV64_IMM(BPF_REG_0, 0),
174 BPF_EXIT_INSN(),
175 },
176 .expected_attach_type = BPF_CGROUP_INET4_POST_BIND,
177 .attach_type = BPF_CGROUP_INET4_POST_BIND,
178 .domain = AF_INET,
179 .type = SOCK_STREAM,
180 .ip = "0.0.0.0",
181 .result = BIND_REJECT,
182 },
183 {
184 .descr = "bind6 reject all",
185 .insns = {
186 BPF_MOV64_IMM(BPF_REG_0, 0),
187 BPF_EXIT_INSN(),
188 },
189 .expected_attach_type = BPF_CGROUP_INET6_POST_BIND,
190 .attach_type = BPF_CGROUP_INET6_POST_BIND,
191 .domain = AF_INET6,
192 .type = SOCK_STREAM,
193 .ip = "::",
194 .result = BIND_REJECT,
195 },
196 {
197 .descr = "bind6 deny specific IP & port",
198 .insns = {
199 BPF_MOV64_REG(BPF_REG_6, BPF_REG_1),
200
201 /* if (ip == expected && port == expected) */
202 BPF_LDX_MEM(BPF_W, BPF_REG_7, BPF_REG_6,
203 offsetof(struct bpf_sock, src_ip6[3])),
204 BPF_JMP_IMM(BPF_JNE, BPF_REG_7,
205 __bpf_constant_ntohl(0x00000001), 4),
206 BPF_LDX_MEM(BPF_W, BPF_REG_7, BPF_REG_6,
207 offsetof(struct bpf_sock, src_port)),
208 BPF_JMP_IMM(BPF_JNE, BPF_REG_7, 0x2001, 2),
209
210 /* return DENY; */
211 BPF_MOV64_IMM(BPF_REG_0, 0),
212 BPF_JMP_A(1),
213
214 /* else return ALLOW; */
215 BPF_MOV64_IMM(BPF_REG_0, 1),
216 BPF_EXIT_INSN(),
217 },
218 .expected_attach_type = BPF_CGROUP_INET6_POST_BIND,
219 .attach_type = BPF_CGROUP_INET6_POST_BIND,
220 .domain = AF_INET6,
221 .type = SOCK_STREAM,
222 .ip = "::1",
223 .port = 8193,
224 .result = BIND_REJECT,
225 },
226 {
227 .descr = "bind4 allow specific IP & port",
228 .insns = {
229 BPF_MOV64_REG(BPF_REG_6, BPF_REG_1),
230
231 /* if (ip == expected && port == expected) */
232 BPF_LDX_MEM(BPF_W, BPF_REG_7, BPF_REG_6,
233 offsetof(struct bpf_sock, src_ip4)),
234 BPF_JMP_IMM(BPF_JNE, BPF_REG_7,
235 __bpf_constant_ntohl(0x7F000001), 4),
236 BPF_LDX_MEM(BPF_W, BPF_REG_7, BPF_REG_6,
237 offsetof(struct bpf_sock, src_port)),
238 BPF_JMP_IMM(BPF_JNE, BPF_REG_7, 0x1002, 2),
239
240 /* return ALLOW; */
241 BPF_MOV64_IMM(BPF_REG_0, 1),
242 BPF_JMP_A(1),
243
244 /* else return DENY; */
245 BPF_MOV64_IMM(BPF_REG_0, 0),
246 BPF_EXIT_INSN(),
247 },
248 .expected_attach_type = BPF_CGROUP_INET4_POST_BIND,
249 .attach_type = BPF_CGROUP_INET4_POST_BIND,
250 .domain = AF_INET,
251 .type = SOCK_STREAM,
252 .ip = "127.0.0.1",
253 .port = 4098,
254 .result = SUCCESS,
255 },
256 {
257 .descr = "bind4 deny specific IP & port of TCP, and retry",
258 .insns = {
259 BPF_MOV64_REG(BPF_REG_6, BPF_REG_1),
260
261 /* if (ip == expected && port == expected) */
262 BPF_LDX_MEM(BPF_W, BPF_REG_7, BPF_REG_6,
263 offsetof(struct bpf_sock, src_ip4)),
264 BPF_JMP_IMM(BPF_JNE, BPF_REG_7,
265 __bpf_constant_ntohl(0x7F000001), 4),
266 BPF_LDX_MEM(BPF_W, BPF_REG_7, BPF_REG_6,
267 offsetof(struct bpf_sock, src_port)),
268 BPF_JMP_IMM(BPF_JNE, BPF_REG_7, 0x1002, 2),
269
270 /* return DENY; */
271 BPF_MOV64_IMM(BPF_REG_0, 0),
272 BPF_JMP_A(1),
273
274 /* else return ALLOW; */
275 BPF_MOV64_IMM(BPF_REG_0, 1),
276 BPF_EXIT_INSN(),
277 },
278 .expected_attach_type = BPF_CGROUP_INET4_POST_BIND,
279 .attach_type = BPF_CGROUP_INET4_POST_BIND,
280 .domain = AF_INET,
281 .type = SOCK_STREAM,
282 .ip = "127.0.0.1",
283 .port = 4098,
284 .port_retry = 5000,
285 .result = RETRY_SUCCESS,
286 },
287 {
288 .descr = "bind4 deny specific IP & port of UDP, and retry",
289 .insns = {
290 BPF_MOV64_REG(BPF_REG_6, BPF_REG_1),
291
292 /* if (ip == expected && port == expected) */
293 BPF_LDX_MEM(BPF_W, BPF_REG_7, BPF_REG_6,
294 offsetof(struct bpf_sock, src_ip4)),
295 BPF_JMP_IMM(BPF_JNE, BPF_REG_7,
296 __bpf_constant_ntohl(0x7F000001), 4),
297 BPF_LDX_MEM(BPF_W, BPF_REG_7, BPF_REG_6,
298 offsetof(struct bpf_sock, src_port)),
299 BPF_JMP_IMM(BPF_JNE, BPF_REG_7, 0x1002, 2),
300
301 /* return DENY; */
302 BPF_MOV64_IMM(BPF_REG_0, 0),
303 BPF_JMP_A(1),
304
305 /* else return ALLOW; */
306 BPF_MOV64_IMM(BPF_REG_0, 1),
307 BPF_EXIT_INSN(),
308 },
309 .expected_attach_type = BPF_CGROUP_INET4_POST_BIND,
310 .attach_type = BPF_CGROUP_INET4_POST_BIND,
311 .domain = AF_INET,
312 .type = SOCK_DGRAM,
313 .ip = "127.0.0.1",
314 .port = 4098,
315 .port_retry = 5000,
316 .result = RETRY_SUCCESS,
317 },
318 {
319 .descr = "bind6 deny specific IP & port, and retry",
320 .insns = {
321 BPF_MOV64_REG(BPF_REG_6, BPF_REG_1),
322
323 /* if (ip == expected && port == expected) */
324 BPF_LDX_MEM(BPF_W, BPF_REG_7, BPF_REG_6,
325 offsetof(struct bpf_sock, src_ip6[3])),
326 BPF_JMP_IMM(BPF_JNE, BPF_REG_7,
327 __bpf_constant_ntohl(0x00000001), 4),
328 BPF_LDX_MEM(BPF_W, BPF_REG_7, BPF_REG_6,
329 offsetof(struct bpf_sock, src_port)),
330 BPF_JMP_IMM(BPF_JNE, BPF_REG_7, 0x2001, 2),
331
332 /* return DENY; */
333 BPF_MOV64_IMM(BPF_REG_0, 0),
334 BPF_JMP_A(1),
335
336 /* else return ALLOW; */
337 BPF_MOV64_IMM(BPF_REG_0, 1),
338 BPF_EXIT_INSN(),
339 },
340 .expected_attach_type = BPF_CGROUP_INET6_POST_BIND,
341 .attach_type = BPF_CGROUP_INET6_POST_BIND,
342 .domain = AF_INET6,
343 .type = SOCK_STREAM,
344 .ip = "::1",
345 .port = 8193,
346 .port_retry = 9000,
347 .result = RETRY_SUCCESS,
348 },
349 {
350 .descr = "bind4 allow all",
351 .insns = {
352 BPF_MOV64_IMM(BPF_REG_0, 1),
353 BPF_EXIT_INSN(),
354 },
355 .expected_attach_type = BPF_CGROUP_INET4_POST_BIND,
356 .attach_type = BPF_CGROUP_INET4_POST_BIND,
357 .domain = AF_INET,
358 .type = SOCK_STREAM,
359 .ip = "0.0.0.0",
360 .result = SUCCESS,
361 },
362 {
363 .descr = "bind6 allow all",
364 .insns = {
365 BPF_MOV64_IMM(BPF_REG_0, 1),
366 BPF_EXIT_INSN(),
367 },
368 .expected_attach_type = BPF_CGROUP_INET6_POST_BIND,
369 .attach_type = BPF_CGROUP_INET6_POST_BIND,
370 .domain = AF_INET6,
371 .type = SOCK_STREAM,
372 .ip = "::",
373 .result = SUCCESS,
374 },
375 };
376
probe_prog_length(const struct bpf_insn * fp)377 static size_t probe_prog_length(const struct bpf_insn *fp)
378 {
379 size_t len;
380
381 for (len = MAX_INSNS - 1; len > 0; --len)
382 if (fp[len].code != 0 || fp[len].imm != 0)
383 break;
384 return len + 1;
385 }
386
load_sock_prog(const struct bpf_insn * prog,enum bpf_attach_type attach_type)387 static int load_sock_prog(const struct bpf_insn *prog,
388 enum bpf_attach_type attach_type)
389 {
390 LIBBPF_OPTS(bpf_prog_load_opts, opts);
391 int ret, insn_cnt;
392
393 insn_cnt = probe_prog_length(prog);
394
395 opts.expected_attach_type = attach_type;
396 opts.log_buf = bpf_log_buf;
397 opts.log_size = BPF_LOG_BUF_SIZE;
398 opts.log_level = 2;
399
400 ret = bpf_prog_load(BPF_PROG_TYPE_CGROUP_SOCK, NULL, "GPL", prog, insn_cnt, &opts);
401 if (verbose && ret < 0)
402 fprintf(stderr, "%s\n", bpf_log_buf);
403
404 return ret;
405 }
406
attach_sock_prog(int cgfd,int progfd,enum bpf_attach_type attach_type)407 static int attach_sock_prog(int cgfd, int progfd,
408 enum bpf_attach_type attach_type)
409 {
410 return bpf_prog_attach(progfd, cgfd, attach_type, BPF_F_ALLOW_OVERRIDE);
411 }
412
bind_sock(int domain,int type,const char * ip,unsigned short port,unsigned short port_retry)413 static int bind_sock(int domain, int type, const char *ip,
414 unsigned short port, unsigned short port_retry)
415 {
416 struct sockaddr_storage addr;
417 struct sockaddr_in6 *addr6;
418 struct sockaddr_in *addr4;
419 int sockfd = -1;
420 socklen_t len;
421 int res = SUCCESS;
422
423 sockfd = socket(domain, type, 0);
424 if (sockfd < 0)
425 goto err;
426
427 memset(&addr, 0, sizeof(addr));
428
429 if (domain == AF_INET) {
430 len = sizeof(struct sockaddr_in);
431 addr4 = (struct sockaddr_in *)&addr;
432 addr4->sin_family = domain;
433 addr4->sin_port = htons(port);
434 if (inet_pton(domain, ip, (void *)&addr4->sin_addr) != 1)
435 goto err;
436 } else if (domain == AF_INET6) {
437 len = sizeof(struct sockaddr_in6);
438 addr6 = (struct sockaddr_in6 *)&addr;
439 addr6->sin6_family = domain;
440 addr6->sin6_port = htons(port);
441 if (inet_pton(domain, ip, (void *)&addr6->sin6_addr) != 1)
442 goto err;
443 } else {
444 goto err;
445 }
446
447 if (bind(sockfd, (const struct sockaddr *)&addr, len) == -1) {
448 /* sys_bind() may fail for different reasons, errno has to be
449 * checked to confirm that BPF program rejected it.
450 */
451 if (errno != EPERM)
452 goto err;
453 if (port_retry)
454 goto retry;
455 res = BIND_REJECT;
456 goto out;
457 }
458
459 goto out;
460 retry:
461 if (domain == AF_INET)
462 addr4->sin_port = htons(port_retry);
463 else
464 addr6->sin6_port = htons(port_retry);
465 if (bind(sockfd, (const struct sockaddr *)&addr, len) == -1) {
466 if (errno != EPERM)
467 goto err;
468 res = RETRY_REJECT;
469 } else {
470 res = RETRY_SUCCESS;
471 }
472 goto out;
473 err:
474 res = -1;
475 out:
476 close(sockfd);
477 return res;
478 }
479
run_test_case(int cgfd,const struct sock_test * test)480 static int run_test_case(int cgfd, const struct sock_test *test)
481 {
482 int progfd = -1;
483 int err = 0;
484 int res;
485
486 printf("Test case: %s .. ", test->descr);
487 progfd = load_sock_prog(test->insns, test->expected_attach_type);
488 if (progfd < 0) {
489 if (test->result == LOAD_REJECT)
490 goto out;
491 else
492 goto err;
493 }
494
495 if (attach_sock_prog(cgfd, progfd, test->attach_type) < 0) {
496 if (test->result == ATTACH_REJECT)
497 goto out;
498 else
499 goto err;
500 }
501
502 res = bind_sock(test->domain, test->type, test->ip, test->port,
503 test->port_retry);
504 if (res > 0 && test->result == res)
505 goto out;
506
507 err:
508 err = -1;
509 out:
510 /* Detaching w/o checking return code: best effort attempt. */
511 if (progfd != -1)
512 bpf_prog_detach(cgfd, test->attach_type);
513 close(progfd);
514 printf("[%s]\n", err ? "FAIL" : "PASS");
515 return err;
516 }
517
run_tests(int cgfd)518 static int run_tests(int cgfd)
519 {
520 int passes = 0;
521 int fails = 0;
522 int i;
523
524 for (i = 0; i < ARRAY_SIZE(tests); ++i) {
525 if (run_test_case(cgfd, &tests[i]))
526 ++fails;
527 else
528 ++passes;
529 }
530 printf("Summary: %d PASSED, %d FAILED\n", passes, fails);
531 return fails ? -1 : 0;
532 }
533
main(int argc,char ** argv)534 int main(int argc, char **argv)
535 {
536 int cgfd = -1;
537 int err = 0;
538
539 cgfd = cgroup_setup_and_join(CG_PATH);
540 if (cgfd < 0)
541 goto err;
542
543 /* Use libbpf 1.0 API mode */
544 libbpf_set_strict_mode(LIBBPF_STRICT_ALL);
545
546 if (run_tests(cgfd))
547 goto err;
548
549 goto out;
550 err:
551 err = -1;
552 out:
553 close(cgfd);
554 cleanup_cgroup_environment();
555 return err;
556 }
557