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1// SPDX-License-Identifier: GPL-2.0
2#include <linux/bpf.h>
3#include <test_progs.h>
4#include "cgroup_helpers.h"
5
6#define TEST_NS "sock_post_bind"
7
8static char bpf_log_buf[4096];
9
10static struct sock_post_bind_test {
11 const char *descr;
12 /* BPF prog properties */
13 const struct bpf_insn insns[64];
14 enum bpf_attach_type attach_type;
15 enum bpf_attach_type expected_attach_type;
16 /* Socket properties */
17 int domain;
18 int type;
19 /* Endpoint to bind() to */
20 const char *ip;
21 unsigned short port;
22 unsigned short port_retry;
23
24 /* Expected test result */
25 enum {
26 ATTACH_REJECT,
27 BIND_REJECT,
28 SUCCESS,
29 RETRY_SUCCESS,
30 RETRY_REJECT
31 } result;
32} tests[] = {
33 {
34 .descr = "attach type mismatch bind4 vs bind6",
35 .insns = {
36 BPF_MOV64_IMM(BPF_REG_0, 1),
37 BPF_EXIT_INSN(),
38 },
39 .expected_attach_type = BPF_CGROUP_INET4_POST_BIND,
40 .attach_type = BPF_CGROUP_INET6_POST_BIND,
41 .result = ATTACH_REJECT,
42 },
43 {
44 .descr = "attach type mismatch bind6 vs bind4",
45 .insns = {
46 BPF_MOV64_IMM(BPF_REG_0, 1),
47 BPF_EXIT_INSN(),
48 },
49 .expected_attach_type = BPF_CGROUP_INET6_POST_BIND,
50 .attach_type = BPF_CGROUP_INET4_POST_BIND,
51 .result = ATTACH_REJECT,
52 },
53 {
54 .descr = "attach type mismatch default vs bind4",
55 .insns = {
56 BPF_MOV64_IMM(BPF_REG_0, 1),
57 BPF_EXIT_INSN(),
58 },
59 .expected_attach_type = 0,
60 .attach_type = BPF_CGROUP_INET4_POST_BIND,
61 .result = ATTACH_REJECT,
62 },
63 {
64 .descr = "attach type mismatch bind6 vs sock_create",
65 .insns = {
66 BPF_MOV64_IMM(BPF_REG_0, 1),
67 BPF_EXIT_INSN(),
68 },
69 .expected_attach_type = BPF_CGROUP_INET6_POST_BIND,
70 .attach_type = BPF_CGROUP_INET_SOCK_CREATE,
71 .result = ATTACH_REJECT,
72 },
73 {
74 .descr = "bind4 reject all",
75 .insns = {
76 BPF_MOV64_IMM(BPF_REG_0, 0),
77 BPF_EXIT_INSN(),
78 },
79 .expected_attach_type = BPF_CGROUP_INET4_POST_BIND,
80 .attach_type = BPF_CGROUP_INET4_POST_BIND,
81 .domain = AF_INET,
82 .type = SOCK_STREAM,
83 .ip = "0.0.0.0",
84 .result = BIND_REJECT,
85 },
86 {
87 .descr = "bind6 reject all",
88 .insns = {
89 BPF_MOV64_IMM(BPF_REG_0, 0),
90 BPF_EXIT_INSN(),
91 },
92 .expected_attach_type = BPF_CGROUP_INET6_POST_BIND,
93 .attach_type = BPF_CGROUP_INET6_POST_BIND,
94 .domain = AF_INET6,
95 .type = SOCK_STREAM,
96 .ip = "::",
97 .result = BIND_REJECT,
98 },
99 {
100 .descr = "bind6 deny specific IP & port",
101 .insns = {
102 BPF_MOV64_REG(BPF_REG_6, BPF_REG_1),
103
104 /* if (ip == expected && port == expected) */
105 BPF_LDX_MEM(BPF_W, BPF_REG_7, BPF_REG_6,
106 offsetof(struct bpf_sock, src_ip6[3])),
107 BPF_JMP_IMM(BPF_JNE, BPF_REG_7,
108 __bpf_constant_ntohl(0x00000001), 4),
109 BPF_LDX_MEM(BPF_W, BPF_REG_7, BPF_REG_6,
110 offsetof(struct bpf_sock, src_port)),
111 BPF_JMP_IMM(BPF_JNE, BPF_REG_7, 0x2001, 2),
112
113 /* return DENY; */
114 BPF_MOV64_IMM(BPF_REG_0, 0),
115 BPF_JMP_A(1),
116
117 /* else return ALLOW; */
118 BPF_MOV64_IMM(BPF_REG_0, 1),
119 BPF_EXIT_INSN(),
120 },
121 .expected_attach_type = BPF_CGROUP_INET6_POST_BIND,
122 .attach_type = BPF_CGROUP_INET6_POST_BIND,
123 .domain = AF_INET6,
124 .type = SOCK_STREAM,
125 .ip = "::1",
126 .port = 8193,
127 .result = BIND_REJECT,
128 },
129 {
130 .descr = "bind4 allow specific IP & port",
131 .insns = {
132 BPF_MOV64_REG(BPF_REG_6, BPF_REG_1),
133
134 /* if (ip == expected && port == expected) */
135 BPF_LDX_MEM(BPF_W, BPF_REG_7, BPF_REG_6,
136 offsetof(struct bpf_sock, src_ip4)),
137 BPF_JMP_IMM(BPF_JNE, BPF_REG_7,
138 __bpf_constant_ntohl(0x7F000001), 4),
139 BPF_LDX_MEM(BPF_W, BPF_REG_7, BPF_REG_6,
140 offsetof(struct bpf_sock, src_port)),
141 BPF_JMP_IMM(BPF_JNE, BPF_REG_7, 0x1002, 2),
142
143 /* return ALLOW; */
144 BPF_MOV64_IMM(BPF_REG_0, 1),
145 BPF_JMP_A(1),
146
147 /* else return DENY; */
148 BPF_MOV64_IMM(BPF_REG_0, 0),
149 BPF_EXIT_INSN(),
150 },
151 .expected_attach_type = BPF_CGROUP_INET4_POST_BIND,
152 .attach_type = BPF_CGROUP_INET4_POST_BIND,
153 .domain = AF_INET,
154 .type = SOCK_STREAM,
155 .ip = "127.0.0.1",
156 .port = 4098,
157 .result = SUCCESS,
158 },
159 {
160 .descr = "bind4 deny specific IP & port of TCP, and retry",
161 .insns = {
162 BPF_MOV64_REG(BPF_REG_6, BPF_REG_1),
163
164 /* if (ip == expected && port == expected) */
165 BPF_LDX_MEM(BPF_W, BPF_REG_7, BPF_REG_6,
166 offsetof(struct bpf_sock, src_ip4)),
167 BPF_JMP_IMM(BPF_JNE, BPF_REG_7,
168 __bpf_constant_ntohl(0x7F000001), 4),
169 BPF_LDX_MEM(BPF_W, BPF_REG_7, BPF_REG_6,
170 offsetof(struct bpf_sock, src_port)),
171 BPF_JMP_IMM(BPF_JNE, BPF_REG_7, 0x1002, 2),
172
173 /* return DENY; */
174 BPF_MOV64_IMM(BPF_REG_0, 0),
175 BPF_JMP_A(1),
176
177 /* else return ALLOW; */
178 BPF_MOV64_IMM(BPF_REG_0, 1),
179 BPF_EXIT_INSN(),
180 },
181 .expected_attach_type = BPF_CGROUP_INET4_POST_BIND,
182 .attach_type = BPF_CGROUP_INET4_POST_BIND,
183 .domain = AF_INET,
184 .type = SOCK_STREAM,
185 .ip = "127.0.0.1",
186 .port = 4098,
187 .port_retry = 5000,
188 .result = RETRY_SUCCESS,
189 },
190 {
191 .descr = "bind4 deny specific IP & port of UDP, and retry",
192 .insns = {
193 BPF_MOV64_REG(BPF_REG_6, BPF_REG_1),
194
195 /* if (ip == expected && port == expected) */
196 BPF_LDX_MEM(BPF_W, BPF_REG_7, BPF_REG_6,
197 offsetof(struct bpf_sock, src_ip4)),
198 BPF_JMP_IMM(BPF_JNE, BPF_REG_7,
199 __bpf_constant_ntohl(0x7F000001), 4),
200 BPF_LDX_MEM(BPF_W, BPF_REG_7, BPF_REG_6,
201 offsetof(struct bpf_sock, src_port)),
202 BPF_JMP_IMM(BPF_JNE, BPF_REG_7, 0x1002, 2),
203
204 /* return DENY; */
205 BPF_MOV64_IMM(BPF_REG_0, 0),
206 BPF_JMP_A(1),
207
208 /* else return ALLOW; */
209 BPF_MOV64_IMM(BPF_REG_0, 1),
210 BPF_EXIT_INSN(),
211 },
212 .expected_attach_type = BPF_CGROUP_INET4_POST_BIND,
213 .attach_type = BPF_CGROUP_INET4_POST_BIND,
214 .domain = AF_INET,
215 .type = SOCK_DGRAM,
216 .ip = "127.0.0.1",
217 .port = 4098,
218 .port_retry = 5000,
219 .result = RETRY_SUCCESS,
220 },
221 {
222 .descr = "bind6 deny specific IP & port, and retry",
223 .insns = {
224 BPF_MOV64_REG(BPF_REG_6, BPF_REG_1),
225
226 /* if (ip == expected && port == expected) */
227 BPF_LDX_MEM(BPF_W, BPF_REG_7, BPF_REG_6,
228 offsetof(struct bpf_sock, src_ip6[3])),
229 BPF_JMP_IMM(BPF_JNE, BPF_REG_7,
230 __bpf_constant_ntohl(0x00000001), 4),
231 BPF_LDX_MEM(BPF_W, BPF_REG_7, BPF_REG_6,
232 offsetof(struct bpf_sock, src_port)),
233 BPF_JMP_IMM(BPF_JNE, BPF_REG_7, 0x2001, 2),
234
235 /* return DENY; */
236 BPF_MOV64_IMM(BPF_REG_0, 0),
237 BPF_JMP_A(1),
238
239 /* else return ALLOW; */
240 BPF_MOV64_IMM(BPF_REG_0, 1),
241 BPF_EXIT_INSN(),
242 },
243 .expected_attach_type = BPF_CGROUP_INET6_POST_BIND,
244 .attach_type = BPF_CGROUP_INET6_POST_BIND,
245 .domain = AF_INET6,
246 .type = SOCK_STREAM,
247 .ip = "::1",
248 .port = 8193,
249 .port_retry = 9000,
250 .result = RETRY_SUCCESS,
251 },
252 {
253 .descr = "bind4 allow all",
254 .insns = {
255 BPF_MOV64_IMM(BPF_REG_0, 1),
256 BPF_EXIT_INSN(),
257 },
258 .expected_attach_type = BPF_CGROUP_INET4_POST_BIND,
259 .attach_type = BPF_CGROUP_INET4_POST_BIND,
260 .domain = AF_INET,
261 .type = SOCK_STREAM,
262 .ip = "0.0.0.0",
263 .result = SUCCESS,
264 },
265 {
266 .descr = "bind6 allow all",
267 .insns = {
268 BPF_MOV64_IMM(BPF_REG_0, 1),
269 BPF_EXIT_INSN(),
270 },
271 .expected_attach_type = BPF_CGROUP_INET6_POST_BIND,
272 .attach_type = BPF_CGROUP_INET6_POST_BIND,
273 .domain = AF_INET6,
274 .type = SOCK_STREAM,
275 .ip = "::",
276 .result = SUCCESS,
277 },
278};
279
280static int load_prog(const struct bpf_insn *insns,
281 enum bpf_attach_type expected_attach_type)
282{
283 LIBBPF_OPTS(bpf_prog_load_opts, opts,
284 .expected_attach_type = expected_attach_type,
285 .log_level = 2,
286 .log_buf = bpf_log_buf,
287 .log_size = sizeof(bpf_log_buf),
288 );
289 int fd, insns_cnt = 0;
290
291 for (;
292 insns[insns_cnt].code != (BPF_JMP | BPF_EXIT);
293 insns_cnt++) {
294 }
295 insns_cnt++;
296
297 fd = bpf_prog_load(BPF_PROG_TYPE_CGROUP_SOCK, NULL, "GPL", insns,
298 insns_cnt, &opts);
299 if (fd < 0)
300 fprintf(stderr, "%s\n", bpf_log_buf);
301
302 return fd;
303}
304
305static int bind_sock(int domain, int type, const char *ip,
306 unsigned short port, unsigned short port_retry)
307{
308 struct sockaddr_storage addr;
309 struct sockaddr_in6 *addr6;
310 struct sockaddr_in *addr4;
311 int sockfd = -1;
312 socklen_t len;
313 int res = SUCCESS;
314
315 sockfd = socket(domain, type, 0);
316 if (sockfd < 0)
317 goto err;
318
319 memset(&addr, 0, sizeof(addr));
320
321 if (domain == AF_INET) {
322 len = sizeof(struct sockaddr_in);
323 addr4 = (struct sockaddr_in *)&addr;
324 addr4->sin_family = domain;
325 addr4->sin_port = htons(port);
326 if (inet_pton(domain, ip, (void *)&addr4->sin_addr) != 1)
327 goto err;
328 } else if (domain == AF_INET6) {
329 len = sizeof(struct sockaddr_in6);
330 addr6 = (struct sockaddr_in6 *)&addr;
331 addr6->sin6_family = domain;
332 addr6->sin6_port = htons(port);
333 if (inet_pton(domain, ip, (void *)&addr6->sin6_addr) != 1)
334 goto err;
335 } else {
336 goto err;
337 }
338
339 if (bind(sockfd, (const struct sockaddr *)&addr, len) == -1) {
340 /* sys_bind() may fail for different reasons, errno has to be
341 * checked to confirm that BPF program rejected it.
342 */
343 if (errno != EPERM)
344 goto err;
345 if (port_retry)
346 goto retry;
347 res = BIND_REJECT;
348 goto out;
349 }
350
351 goto out;
352retry:
353 if (domain == AF_INET)
354 addr4->sin_port = htons(port_retry);
355 else
356 addr6->sin6_port = htons(port_retry);
357 if (bind(sockfd, (const struct sockaddr *)&addr, len) == -1) {
358 if (errno != EPERM)
359 goto err;
360 res = RETRY_REJECT;
361 } else {
362 res = RETRY_SUCCESS;
363 }
364 goto out;
365err:
366 res = -1;
367out:
368 close(sockfd);
369 return res;
370}
371
372static int run_test(int cgroup_fd, struct sock_post_bind_test *test)
373{
374 int err, prog_fd, res, ret = 0;
375
376 prog_fd = load_prog(test->insns, test->expected_attach_type);
377 if (prog_fd < 0)
378 goto err;
379
380 err = bpf_prog_attach(prog_fd, cgroup_fd, test->attach_type, 0);
381 if (err < 0) {
382 if (test->result == ATTACH_REJECT)
383 goto out;
384 else
385 goto err;
386 }
387
388 res = bind_sock(test->domain, test->type, test->ip, test->port,
389 test->port_retry);
390 if (res > 0 && test->result == res)
391 goto out;
392err:
393 ret = -1;
394out:
395 /* Detaching w/o checking return code: best effort attempt. */
396 if (prog_fd != -1)
397 bpf_prog_detach(cgroup_fd, test->attach_type);
398 close(prog_fd);
399 return ret;
400}
401
402void test_sock_post_bind(void)
403{
404 struct netns_obj *ns;
405 int cgroup_fd;
406 int i;
407
408 cgroup_fd = test__join_cgroup("/post_bind");
409 if (!ASSERT_OK_FD(cgroup_fd, "join_cgroup"))
410 return;
411
412 ns = netns_new(TEST_NS, true);
413 if (!ASSERT_OK_PTR(ns, "netns_new"))
414 goto cleanup;
415
416 for (i = 0; i < ARRAY_SIZE(tests); i++) {
417 if (!test__start_subtest(tests[i].descr))
418 continue;
419
420 ASSERT_OK(run_test(cgroup_fd, &tests[i]), tests[i].descr);
421 }
422
423cleanup:
424 netns_free(ns);
425 close(cgroup_fd);
426}