samples/bpf/test_cgrp2_attach2.c

   1 /* eBPF example program:
   2  *
   3  * - Creates arraymap in kernel with 4 bytes keys and 8 byte values
   4  *
   5  * - Loads eBPF program
   6  *
   7  *   The eBPF program accesses the map passed in to store two pieces of
   8  *   information. The number of invocations of the program, which maps
   9  *   to the number of packets received, is stored to key 0. Key 1 is
  10  *   incremented on each iteration by the number of bytes stored in
  11  *   the skb. The program also stores the number of received bytes
  12  *   in the cgroup storage.
  13  *
  14  * - Attaches the new program to a cgroup using BPF_PROG_ATTACH
  15  *
  16  * - Every second, reads map[0] and map[1] to see how many bytes and
  17  *   packets were seen on any socket of tasks in the given cgroup.
  18  */
  19
  20 #define _GNU_SOURCE
  21
  22 #include <stdio.h>
  23 #include <stdlib.h>
  24 #include <assert.h>
  25 #include <sys/resource.h>
  26 #include <sys/time.h>
  27 #include <unistd.h>
  28
  29 #include <linux/bpf.h>
  30 #include <bpf/bpf.h>
  31
  32 #include "bpf_insn.h"
  33 #include "bpf_rlimit.h"
  34 #include "cgroup_helpers.h"
  35
  36 #define FOO             "/foo"
  37 #define BAR             "/foo/bar/"
  38 #define PING_CMD        "ping -c1 -w1 127.0.0.1 > /dev/null"
  39
  40 char bpf_log_buf[BPF_LOG_BUF_SIZE];
  41
  42 static int prog_load(int verdict)
  43 {
  44         int ret;
  45         struct bpf_insn prog[] = {
  46                 BPF_MOV64_IMM(BPF_REG_0, verdict), /* r0 = verdict */
  47                 BPF_EXIT_INSN(),
  48         };
  49         size_t insns_cnt = sizeof(prog) / sizeof(struct bpf_insn);
  50
  51         ret = bpf_load_program(BPF_PROG_TYPE_CGROUP_SKB,
  52                                prog, insns_cnt, "GPL", 0,
  53                                bpf_log_buf, BPF_LOG_BUF_SIZE);
  54
  55         if (ret < 0) {
  56                 log_err("Loading program");
  57                 printf("Output from verifier:\n%s\n-------\n", bpf_log_buf);
  58                 return 0;
  59         }
  60         return ret;
  61 }
  62
  63 static int test_foo_bar(void)
  64 {
  65         int drop_prog, allow_prog, foo = 0, bar = 0, rc = 0;
  66
  67         allow_prog = prog_load(1);
  68         if (!allow_prog)
  69                 goto err;
  70
  71         drop_prog = prog_load(0);
  72         if (!drop_prog)
  73                 goto err;
  74
  75         if (setup_cgroup_environment())
  76                 goto err;
  77
  78         /* Create cgroup /foo, get fd, and join it */
  79         foo = create_and_get_cgroup(FOO);
  80         if (!foo)
  81                 goto err;
  82
  83         if (join_cgroup(FOO))
  84                 goto err;
  85
  86         if (bpf_prog_attach(drop_prog, foo, BPF_CGROUP_INET_EGRESS,
  87                             BPF_F_ALLOW_OVERRIDE)) {
  88                 log_err("Attaching prog to /foo");
  89                 goto err;
  90         }
  91
  92         printf("Attached DROP prog. This ping in cgroup /foo should fail...\n");
  93         assert(system(PING_CMD) != 0);
  94
  95         /* Create cgroup /foo/bar, get fd, and join it */
  96         bar = create_and_get_cgroup(BAR);
  97         if (!bar)
  98                 goto err;
  99
 100         if (join_cgroup(BAR))
 101                 goto err;
 102
 103         printf("Attached DROP prog. This ping in cgroup /foo/bar should fail...\n");
 104         assert(system(PING_CMD) != 0);
 105
 106         if (bpf_prog_attach(allow_prog, bar, BPF_CGROUP_INET_EGRESS,
 107                             BPF_F_ALLOW_OVERRIDE)) {
 108                 log_err("Attaching prog to /foo/bar");
 109                 goto err;
 110         }
 111
 112         printf("Attached PASS prog. This ping in cgroup /foo/bar should pass...\n");
 113         assert(system(PING_CMD) == 0);
 114
 115         if (bpf_prog_detach(bar, BPF_CGROUP_INET_EGRESS)) {
 116                 log_err("Detaching program from /foo/bar");
 117                 goto err;
 118         }
 119
 120         printf("Detached PASS from /foo/bar while DROP is attached to /foo.\n"
 121                "This ping in cgroup /foo/bar should fail...\n");
 122         assert(system(PING_CMD) != 0);
 123
 124         if (bpf_prog_attach(allow_prog, bar, BPF_CGROUP_INET_EGRESS,
 125                             BPF_F_ALLOW_OVERRIDE)) {
 126                 log_err("Attaching prog to /foo/bar");
 127                 goto err;
 128         }
 129
 130         if (bpf_prog_detach(foo, BPF_CGROUP_INET_EGRESS)) {
 131                 log_err("Detaching program from /foo");
 132                 goto err;
 133         }
 134
 135         printf("Attached PASS from /foo/bar and detached DROP from /foo.\n"
 136                "This ping in cgroup /foo/bar should pass...\n");
 137         assert(system(PING_CMD) == 0);
 138
 139         if (bpf_prog_attach(allow_prog, bar, BPF_CGROUP_INET_EGRESS,
 140                             BPF_F_ALLOW_OVERRIDE)) {
 141                 log_err("Attaching prog to /foo/bar");
 142                 goto err;
 143         }
 144
 145         if (!bpf_prog_attach(allow_prog, bar, BPF_CGROUP_INET_EGRESS, 0)) {
 146                 errno = 0;
 147                 log_err("Unexpected success attaching prog to /foo/bar");
 148                 goto err;
 149         }
 150
 151         if (bpf_prog_detach(bar, BPF_CGROUP_INET_EGRESS)) {
 152                 log_err("Detaching program from /foo/bar");
 153                 goto err;
 154         }
 155
 156         if (!bpf_prog_detach(foo, BPF_CGROUP_INET_EGRESS)) {
 157                 errno = 0;
 158                 log_err("Unexpected success in double detach from /foo");
 159                 goto err;
 160         }
 161
 162         if (bpf_prog_attach(allow_prog, foo, BPF_CGROUP_INET_EGRESS, 0)) {
 163                 log_err("Attaching non-overridable prog to /foo");
 164                 goto err;
 165         }
 166
 167         if (!bpf_prog_attach(allow_prog, bar, BPF_CGROUP_INET_EGRESS, 0)) {
 168                 errno = 0;
 169                 log_err("Unexpected success attaching non-overridable prog to /foo/bar");
 170                 goto err;
 171         }
 172
 173         if (!bpf_prog_attach(allow_prog, bar, BPF_CGROUP_INET_EGRESS,
 174                              BPF_F_ALLOW_OVERRIDE)) {
 175                 errno = 0;
 176                 log_err("Unexpected success attaching overridable prog to /foo/bar");
 177                 goto err;
 178         }
 179
 180         if (!bpf_prog_attach(allow_prog, foo, BPF_CGROUP_INET_EGRESS,
 181                              BPF_F_ALLOW_OVERRIDE)) {
 182                 errno = 0;
 183                 log_err("Unexpected success attaching overridable prog to /foo");
 184                 goto err;
 185         }
 186
 187         if (bpf_prog_attach(drop_prog, foo, BPF_CGROUP_INET_EGRESS, 0)) {
 188                 log_err("Attaching different non-overridable prog to /foo");
 189                 goto err;
 190         }
 191
 192         goto out;
 193
 194 err:
 195         rc = 1;
 196
 197 out:
 198         close(foo);
 199         close(bar);
 200         cleanup_cgroup_environment();
 201         if (!rc)
 202                 printf("### override:PASS\n");
 203         else
 204                 printf("### override:FAIL\n");
 205         return rc;
 206 }
 207
 208 static int map_fd = -1;
 209
 210 static int prog_load_cnt(int verdict, int val)
 211 {
 212         int cgroup_storage_fd;
 213
 214         if (map_fd < 0)
 215                 map_fd = bpf_create_map(BPF_MAP_TYPE_ARRAY, 4, 8, 1, 0);
 216         if (map_fd < 0) {
 217                 printf("failed to create map '%s'\n", strerror(errno));
 218                 return -1;
 219         }
 220
 221         cgroup_storage_fd = bpf_create_map(BPF_MAP_TYPE_CGROUP_STORAGE,
 222                                 sizeof(struct bpf_cgroup_storage_key), 8, 0, 0);
 223         if (cgroup_storage_fd < 0) {
 224                 printf("failed to create map '%s'\n", strerror(errno));
 225                 return -1;
 226         }
 227
 228         struct bpf_insn prog[] = {
 229                 BPF_MOV32_IMM(BPF_REG_0, 0),
 230                 BPF_STX_MEM(BPF_W, BPF_REG_10, BPF_REG_0, -4), /* *(u32 *)(fp - 4) = r0 */
 231                 BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
 232                 BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -4), /* r2 = fp - 4 */
 233                 BPF_LD_MAP_FD(BPF_REG_1, map_fd),
 234                 BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_map_lookup_elem),
 235                 BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 2),
 236                 BPF_MOV64_IMM(BPF_REG_1, val), /* r1 = 1 */
 237                 BPF_RAW_INSN(BPF_STX | BPF_XADD | BPF_DW, BPF_REG_0, BPF_REG_1, 0, 0), /* xadd r0 += r1 */
 238                 BPF_LD_MAP_FD(BPF_REG_1, cgroup_storage_fd),
 239                 BPF_MOV64_IMM(BPF_REG_2, 0),
 240                 BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_get_local_storage),
 241                 BPF_MOV64_IMM(BPF_REG_1, val),
 242                 BPF_RAW_INSN(BPF_STX | BPF_XADD | BPF_W, BPF_REG_0, BPF_REG_1, 0, 0),
 243                 BPF_MOV64_IMM(BPF_REG_0, verdict), /* r0 = verdict */
 244                 BPF_EXIT_INSN(),
 245         };
 246         size_t insns_cnt = sizeof(prog) / sizeof(struct bpf_insn);
 247         int ret;
 248
 249         ret = bpf_load_program(BPF_PROG_TYPE_CGROUP_SKB,
 250                                prog, insns_cnt, "GPL", 0,
 251                                bpf_log_buf, BPF_LOG_BUF_SIZE);
 252
 253         if (ret < 0) {
 254                 log_err("Loading program");
 255                 printf("Output from verifier:\n%s\n-------\n", bpf_log_buf);
 256                 return 0;
 257         }
 258         close(cgroup_storage_fd);
 259         return ret;
 260 }
 261
 262
 263 static int test_multiprog(void)
 264 {
 265         __u32 prog_ids[4], prog_cnt = 0, attach_flags, saved_prog_id;
 266         int cg1 = 0, cg2 = 0, cg3 = 0, cg4 = 0, cg5 = 0, key = 0;
 267         int drop_prog, allow_prog[6] = {}, rc = 0;
 268         unsigned long long value;
 269         int i = 0;
 270
 271         for (i = 0; i < 6; i++) {
 272                 allow_prog[i] = prog_load_cnt(1, 1 << i);
 273                 if (!allow_prog[i])
 274                         goto err;
 275         }
 276         drop_prog = prog_load_cnt(0, 1);
 277         if (!drop_prog)
 278                 goto err;
 279
 280         if (setup_cgroup_environment())
 281                 goto err;
 282
 283         cg1 = create_and_get_cgroup("/cg1");
 284         if (!cg1)
 285                 goto err;
 286         cg2 = create_and_get_cgroup("/cg1/cg2");
 287         if (!cg2)
 288                 goto err;
 289         cg3 = create_and_get_cgroup("/cg1/cg2/cg3");
 290         if (!cg3)
 291                 goto err;
 292         cg4 = create_and_get_cgroup("/cg1/cg2/cg3/cg4");
 293         if (!cg4)
 294                 goto err;
 295         cg5 = create_and_get_cgroup("/cg1/cg2/cg3/cg4/cg5");
 296         if (!cg5)
 297                 goto err;
 298
 299         if (join_cgroup("/cg1/cg2/cg3/cg4/cg5"))
 300                 goto err;
 301
 302         if (bpf_prog_attach(allow_prog[0], cg1, BPF_CGROUP_INET_EGRESS,
 303                             BPF_F_ALLOW_MULTI)) {
 304                 log_err("Attaching prog to cg1");
 305                 goto err;
 306         }
 307         if (!bpf_prog_attach(allow_prog[0], cg1, BPF_CGROUP_INET_EGRESS,
 308                              BPF_F_ALLOW_MULTI)) {
 309                 log_err("Unexpected success attaching the same prog to cg1");
 310                 goto err;
 311         }
 312         if (bpf_prog_attach(allow_prog[1], cg1, BPF_CGROUP_INET_EGRESS,
 313                             BPF_F_ALLOW_MULTI)) {
 314                 log_err("Attaching prog2 to cg1");
 315                 goto err;
 316         }
 317         if (bpf_prog_attach(allow_prog[2], cg2, BPF_CGROUP_INET_EGRESS,
 318                             BPF_F_ALLOW_OVERRIDE)) {
 319                 log_err("Attaching prog to cg2");
 320                 goto err;
 321         }
 322         if (bpf_prog_attach(allow_prog[3], cg3, BPF_CGROUP_INET_EGRESS,
 323                             BPF_F_ALLOW_MULTI)) {
 324                 log_err("Attaching prog to cg3");
 325                 goto err;
 326         }
 327         if (bpf_prog_attach(allow_prog[4], cg4, BPF_CGROUP_INET_EGRESS,
 328                             BPF_F_ALLOW_OVERRIDE)) {
 329                 log_err("Attaching prog to cg4");
 330                 goto err;
 331         }
 332         if (bpf_prog_attach(allow_prog[5], cg5, BPF_CGROUP_INET_EGRESS, 0)) {
 333                 log_err("Attaching prog to cg5");
 334                 goto err;
 335         }
 336         assert(system(PING_CMD) == 0);
 337         assert(bpf_map_lookup_elem(map_fd, &key, &value) == 0);
 338         assert(value == 1 + 2 + 8 + 32);
 339
 340         /* query the number of effective progs in cg5 */
 341         assert(bpf_prog_query(cg5, BPF_CGROUP_INET_EGRESS, BPF_F_QUERY_EFFECTIVE,
 342                               NULL, NULL, &prog_cnt) == 0);
 343         assert(prog_cnt == 4);
 344         /* retrieve prog_ids of effective progs in cg5 */
 345         assert(bpf_prog_query(cg5, BPF_CGROUP_INET_EGRESS, BPF_F_QUERY_EFFECTIVE,
 346                               &attach_flags, prog_ids, &prog_cnt) == 0);
 347         assert(prog_cnt == 4);
 348         assert(attach_flags == 0);
 349         saved_prog_id = prog_ids[0];
 350         /* check enospc handling */
 351         prog_ids[0] = 0;
 352         prog_cnt = 2;
 353         assert(bpf_prog_query(cg5, BPF_CGROUP_INET_EGRESS, BPF_F_QUERY_EFFECTIVE,
 354                               &attach_flags, prog_ids, &prog_cnt) == -1 &&
 355                errno == ENOSPC);
 356         assert(prog_cnt == 4);
 357         /* check that prog_ids are returned even when buffer is too small */
 358         assert(prog_ids[0] == saved_prog_id);
 359         /* retrieve prog_id of single attached prog in cg5 */
 360         prog_ids[0] = 0;
 361         assert(bpf_prog_query(cg5, BPF_CGROUP_INET_EGRESS, 0,
 362                               NULL, prog_ids, &prog_cnt) == 0);
 363         assert(prog_cnt == 1);
 364         assert(prog_ids[0] == saved_prog_id);
 365
 366         /* detach bottom program and ping again */
 367         if (bpf_prog_detach2(-1, cg5, BPF_CGROUP_INET_EGRESS)) {
 368                 log_err("Detaching prog from cg5");
 369                 goto err;
 370         }
 371         value = 0;
 372         assert(bpf_map_update_elem(map_fd, &key, &value, 0) == 0);
 373         assert(system(PING_CMD) == 0);
 374         assert(bpf_map_lookup_elem(map_fd, &key, &value) == 0);
 375         assert(value == 1 + 2 + 8 + 16);
 376
 377         /* detach 3rd from bottom program and ping again */
 378         errno = 0;
 379         if (!bpf_prog_detach2(0, cg3, BPF_CGROUP_INET_EGRESS)) {
 380                 log_err("Unexpected success on detach from cg3");
 381                 goto err;
 382         }
 383         if (bpf_prog_detach2(allow_prog[3], cg3, BPF_CGROUP_INET_EGRESS)) {
 384                 log_err("Detaching from cg3");
 385                 goto err;
 386         }
 387         value = 0;
 388         assert(bpf_map_update_elem(map_fd, &key, &value, 0) == 0);
 389         assert(system(PING_CMD) == 0);
 390         assert(bpf_map_lookup_elem(map_fd, &key, &value) == 0);
 391         assert(value == 1 + 2 + 16);
 392
 393         /* detach 2nd from bottom program and ping again */
 394         if (bpf_prog_detach2(-1, cg4, BPF_CGROUP_INET_EGRESS)) {
 395                 log_err("Detaching prog from cg4");
 396                 goto err;
 397         }
 398         value = 0;
 399         assert(bpf_map_update_elem(map_fd, &key, &value, 0) == 0);
 400         assert(system(PING_CMD) == 0);
 401         assert(bpf_map_lookup_elem(map_fd, &key, &value) == 0);
 402         assert(value == 1 + 2 + 4);
 403
 404         prog_cnt = 4;
 405         assert(bpf_prog_query(cg5, BPF_CGROUP_INET_EGRESS, BPF_F_QUERY_EFFECTIVE,
 406                               &attach_flags, prog_ids, &prog_cnt) == 0);
 407         assert(prog_cnt == 3);
 408         assert(attach_flags == 0);
 409         assert(bpf_prog_query(cg5, BPF_CGROUP_INET_EGRESS, 0,
 410                               NULL, prog_ids, &prog_cnt) == 0);
 411         assert(prog_cnt == 0);
 412         goto out;
 413 err:
 414         rc = 1;
 415
 416 out:
 417         for (i = 0; i < 6; i++)
 418                 if (allow_prog[i] > 0)
 419                         close(allow_prog[i]);
 420         close(cg1);
 421         close(cg2);
 422         close(cg3);
 423         close(cg4);
 424         close(cg5);
 425         cleanup_cgroup_environment();
 426         if (!rc)
 427                 printf("### multi:PASS\n");
 428         else
 429                 printf("### multi:FAIL\n");
 430         return rc;
 431 }
 432
 433 int main(int argc, char **argv)
 434 {
 435         int rc = 0;
 436
 437         rc = test_foo_bar();
 438         if (rc)
 439                 return rc;
 440
 441         return test_multiprog();
 442 }